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llvm-project/clang/lib/Sema/SemaChecking.cpp

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//===--- SemaChecking.cpp - Extra Semantic Checking -----------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements extra semantic analysis beyond what is enforced
// by the C type system.
//
//===----------------------------------------------------------------------===//
#include "clang/Sema/Initialization.h"
#include "clang/Sema/Sema.h"
#include "clang/Sema/SemaInternal.h"
#include "clang/Sema/Initialization.h"
#include "clang/Sema/Lookup.h"
#include "clang/Sema/ScopeInfo.h"
#include "clang/Analysis/Analyses/FormatString.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/CharUnits.h"
#include "clang/AST/DeclCXX.h"
#include "clang/AST/DeclObjC.h"
#include "clang/AST/Expr.h"
#include "clang/AST/ExprCXX.h"
#include "clang/AST/ExprObjC.h"
#include "clang/AST/EvaluatedExprVisitor.h"
#include "clang/AST/DeclObjC.h"
#include "clang/AST/StmtCXX.h"
#include "clang/AST/StmtObjC.h"
#include "clang/Lex/Preprocessor.h"
#include "llvm/ADT/BitVector.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/Support/raw_ostream.h"
#include "clang/Basic/TargetBuiltins.h"
#include "clang/Basic/TargetInfo.h"
#include "clang/Basic/ConvertUTF.h"
#include <limits>
using namespace clang;
using namespace sema;
SourceLocation Sema::getLocationOfStringLiteralByte(const StringLiteral *SL,
unsigned ByteNo) const {
return SL->getLocationOfByte(ByteNo, PP.getSourceManager(),
PP.getLangOpts(), PP.getTargetInfo());
}
/// Checks that a call expression's argument count is the desired number.
/// This is useful when doing custom type-checking. Returns true on error.
static bool checkArgCount(Sema &S, CallExpr *call, unsigned desiredArgCount) {
unsigned argCount = call->getNumArgs();
if (argCount == desiredArgCount) return false;
if (argCount < desiredArgCount)
return S.Diag(call->getLocEnd(), diag::err_typecheck_call_too_few_args)
<< 0 /*function call*/ << desiredArgCount << argCount
<< call->getSourceRange();
// Highlight all the excess arguments.
SourceRange range(call->getArg(desiredArgCount)->getLocStart(),
call->getArg(argCount - 1)->getLocEnd());
return S.Diag(range.getBegin(), diag::err_typecheck_call_too_many_args)
<< 0 /*function call*/ << desiredArgCount << argCount
<< call->getArg(1)->getSourceRange();
}
/// Check that the first argument to __builtin_annotation is an integer
/// and the second argument is a non-wide string literal.
static bool SemaBuiltinAnnotation(Sema &S, CallExpr *TheCall) {
if (checkArgCount(S, TheCall, 2))
return true;
// First argument should be an integer.
Expr *ValArg = TheCall->getArg(0);
QualType Ty = ValArg->getType();
if (!Ty->isIntegerType()) {
S.Diag(ValArg->getLocStart(), diag::err_builtin_annotation_first_arg)
<< ValArg->getSourceRange();
return true;
}
// Second argument should be a constant string.
Expr *StrArg = TheCall->getArg(1)->IgnoreParenCasts();
StringLiteral *Literal = dyn_cast<StringLiteral>(StrArg);
if (!Literal || !Literal->isAscii()) {
S.Diag(StrArg->getLocStart(), diag::err_builtin_annotation_second_arg)
<< StrArg->getSourceRange();
return true;
}
TheCall->setType(Ty);
return false;
}
ExprResult
Sema::CheckBuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall) {
ExprResult TheCallResult(Owned(TheCall));
// Find out if any arguments are required to be integer constant expressions.
unsigned ICEArguments = 0;
ASTContext::GetBuiltinTypeError Error;
Context.GetBuiltinType(BuiltinID, Error, &ICEArguments);
if (Error != ASTContext::GE_None)
ICEArguments = 0; // Don't diagnose previously diagnosed errors.
// If any arguments are required to be ICE's, check and diagnose.
for (unsigned ArgNo = 0; ICEArguments != 0; ++ArgNo) {
// Skip arguments not required to be ICE's.
if ((ICEArguments & (1 << ArgNo)) == 0) continue;
llvm::APSInt Result;
if (SemaBuiltinConstantArg(TheCall, ArgNo, Result))
return true;
ICEArguments &= ~(1 << ArgNo);
}
switch (BuiltinID) {
case Builtin::BI__builtin___CFStringMakeConstantString:
assert(TheCall->getNumArgs() == 1 &&
"Wrong # arguments to builtin CFStringMakeConstantString");
if (CheckObjCString(TheCall->getArg(0)))
return ExprError();
break;
case Builtin::BI__builtin_stdarg_start:
case Builtin::BI__builtin_va_start:
if (SemaBuiltinVAStart(TheCall))
return ExprError();
break;
case Builtin::BI__builtin_isgreater:
case Builtin::BI__builtin_isgreaterequal:
case Builtin::BI__builtin_isless:
case Builtin::BI__builtin_islessequal:
case Builtin::BI__builtin_islessgreater:
case Builtin::BI__builtin_isunordered:
if (SemaBuiltinUnorderedCompare(TheCall))
return ExprError();
break;
case Builtin::BI__builtin_fpclassify:
if (SemaBuiltinFPClassification(TheCall, 6))
return ExprError();
break;
case Builtin::BI__builtin_isfinite:
case Builtin::BI__builtin_isinf:
case Builtin::BI__builtin_isinf_sign:
case Builtin::BI__builtin_isnan:
case Builtin::BI__builtin_isnormal:
if (SemaBuiltinFPClassification(TheCall, 1))
return ExprError();
break;
case Builtin::BI__builtin_shufflevector:
return SemaBuiltinShuffleVector(TheCall);
// TheCall will be freed by the smart pointer here, but that's fine, since
// SemaBuiltinShuffleVector guts it, but then doesn't release it.
case Builtin::BI__builtin_prefetch:
if (SemaBuiltinPrefetch(TheCall))
return ExprError();
break;
case Builtin::BI__builtin_object_size:
if (SemaBuiltinObjectSize(TheCall))
return ExprError();
break;
case Builtin::BI__builtin_longjmp:
if (SemaBuiltinLongjmp(TheCall))
return ExprError();
break;
case Builtin::BI__builtin_classify_type:
if (checkArgCount(*this, TheCall, 1)) return true;
TheCall->setType(Context.IntTy);
break;
case Builtin::BI__builtin_constant_p:
if (checkArgCount(*this, TheCall, 1)) return true;
TheCall->setType(Context.IntTy);
break;
case Builtin::BI__sync_fetch_and_add:
case Builtin::BI__sync_fetch_and_add_1:
case Builtin::BI__sync_fetch_and_add_2:
case Builtin::BI__sync_fetch_and_add_4:
case Builtin::BI__sync_fetch_and_add_8:
case Builtin::BI__sync_fetch_and_add_16:
case Builtin::BI__sync_fetch_and_sub:
case Builtin::BI__sync_fetch_and_sub_1:
case Builtin::BI__sync_fetch_and_sub_2:
case Builtin::BI__sync_fetch_and_sub_4:
case Builtin::BI__sync_fetch_and_sub_8:
case Builtin::BI__sync_fetch_and_sub_16:
case Builtin::BI__sync_fetch_and_or:
case Builtin::BI__sync_fetch_and_or_1:
case Builtin::BI__sync_fetch_and_or_2:
case Builtin::BI__sync_fetch_and_or_4:
case Builtin::BI__sync_fetch_and_or_8:
case Builtin::BI__sync_fetch_and_or_16:
case Builtin::BI__sync_fetch_and_and:
case Builtin::BI__sync_fetch_and_and_1:
case Builtin::BI__sync_fetch_and_and_2:
case Builtin::BI__sync_fetch_and_and_4:
case Builtin::BI__sync_fetch_and_and_8:
case Builtin::BI__sync_fetch_and_and_16:
case Builtin::BI__sync_fetch_and_xor:
case Builtin::BI__sync_fetch_and_xor_1:
case Builtin::BI__sync_fetch_and_xor_2:
case Builtin::BI__sync_fetch_and_xor_4:
case Builtin::BI__sync_fetch_and_xor_8:
case Builtin::BI__sync_fetch_and_xor_16:
case Builtin::BI__sync_add_and_fetch:
case Builtin::BI__sync_add_and_fetch_1:
case Builtin::BI__sync_add_and_fetch_2:
case Builtin::BI__sync_add_and_fetch_4:
case Builtin::BI__sync_add_and_fetch_8:
case Builtin::BI__sync_add_and_fetch_16:
case Builtin::BI__sync_sub_and_fetch:
case Builtin::BI__sync_sub_and_fetch_1:
case Builtin::BI__sync_sub_and_fetch_2:
case Builtin::BI__sync_sub_and_fetch_4:
case Builtin::BI__sync_sub_and_fetch_8:
case Builtin::BI__sync_sub_and_fetch_16:
case Builtin::BI__sync_and_and_fetch:
case Builtin::BI__sync_and_and_fetch_1:
case Builtin::BI__sync_and_and_fetch_2:
case Builtin::BI__sync_and_and_fetch_4:
case Builtin::BI__sync_and_and_fetch_8:
case Builtin::BI__sync_and_and_fetch_16:
case Builtin::BI__sync_or_and_fetch:
case Builtin::BI__sync_or_and_fetch_1:
case Builtin::BI__sync_or_and_fetch_2:
case Builtin::BI__sync_or_and_fetch_4:
case Builtin::BI__sync_or_and_fetch_8:
case Builtin::BI__sync_or_and_fetch_16:
case Builtin::BI__sync_xor_and_fetch:
case Builtin::BI__sync_xor_and_fetch_1:
case Builtin::BI__sync_xor_and_fetch_2:
case Builtin::BI__sync_xor_and_fetch_4:
case Builtin::BI__sync_xor_and_fetch_8:
case Builtin::BI__sync_xor_and_fetch_16:
case Builtin::BI__sync_val_compare_and_swap:
case Builtin::BI__sync_val_compare_and_swap_1:
case Builtin::BI__sync_val_compare_and_swap_2:
case Builtin::BI__sync_val_compare_and_swap_4:
case Builtin::BI__sync_val_compare_and_swap_8:
case Builtin::BI__sync_val_compare_and_swap_16:
case Builtin::BI__sync_bool_compare_and_swap:
case Builtin::BI__sync_bool_compare_and_swap_1:
case Builtin::BI__sync_bool_compare_and_swap_2:
case Builtin::BI__sync_bool_compare_and_swap_4:
case Builtin::BI__sync_bool_compare_and_swap_8:
case Builtin::BI__sync_bool_compare_and_swap_16:
case Builtin::BI__sync_lock_test_and_set:
case Builtin::BI__sync_lock_test_and_set_1:
case Builtin::BI__sync_lock_test_and_set_2:
case Builtin::BI__sync_lock_test_and_set_4:
case Builtin::BI__sync_lock_test_and_set_8:
case Builtin::BI__sync_lock_test_and_set_16:
case Builtin::BI__sync_lock_release:
case Builtin::BI__sync_lock_release_1:
case Builtin::BI__sync_lock_release_2:
case Builtin::BI__sync_lock_release_4:
case Builtin::BI__sync_lock_release_8:
case Builtin::BI__sync_lock_release_16:
case Builtin::BI__sync_swap:
case Builtin::BI__sync_swap_1:
case Builtin::BI__sync_swap_2:
case Builtin::BI__sync_swap_4:
case Builtin::BI__sync_swap_8:
case Builtin::BI__sync_swap_16:
return SemaBuiltinAtomicOverloaded(move(TheCallResult));
#define BUILTIN(ID, TYPE, ATTRS)
#define ATOMIC_BUILTIN(ID, TYPE, ATTRS) \
case Builtin::BI##ID: \
return SemaAtomicOpsOverloaded(move(TheCallResult), AtomicExpr::AO##ID);
#include "clang/Basic/Builtins.def"
case Builtin::BI__builtin_annotation:
if (SemaBuiltinAnnotation(*this, TheCall))
return ExprError();
break;
}
// Since the target specific builtins for each arch overlap, only check those
// of the arch we are compiling for.
if (BuiltinID >= Builtin::FirstTSBuiltin) {
switch (Context.getTargetInfo().getTriple().getArch()) {
case llvm::Triple::arm:
case llvm::Triple::thumb:
if (CheckARMBuiltinFunctionCall(BuiltinID, TheCall))
return ExprError();
break;
default:
break;
}
}
return move(TheCallResult);
}
// Get the valid immediate range for the specified NEON type code.
static unsigned RFT(unsigned t, bool shift = false) {
NeonTypeFlags Type(t);
int IsQuad = Type.isQuad();
switch (Type.getEltType()) {
case NeonTypeFlags::Int8:
case NeonTypeFlags::Poly8:
return shift ? 7 : (8 << IsQuad) - 1;
case NeonTypeFlags::Int16:
case NeonTypeFlags::Poly16:
return shift ? 15 : (4 << IsQuad) - 1;
case NeonTypeFlags::Int32:
return shift ? 31 : (2 << IsQuad) - 1;
case NeonTypeFlags::Int64:
return shift ? 63 : (1 << IsQuad) - 1;
case NeonTypeFlags::Float16:
assert(!shift && "cannot shift float types!");
return (4 << IsQuad) - 1;
case NeonTypeFlags::Float32:
assert(!shift && "cannot shift float types!");
return (2 << IsQuad) - 1;
}
llvm_unreachable("Invalid NeonTypeFlag!");
}
/// getNeonEltType - Return the QualType corresponding to the elements of
/// the vector type specified by the NeonTypeFlags. This is used to check
/// the pointer arguments for Neon load/store intrinsics.
static QualType getNeonEltType(NeonTypeFlags Flags, ASTContext &Context) {
switch (Flags.getEltType()) {
case NeonTypeFlags::Int8:
return Flags.isUnsigned() ? Context.UnsignedCharTy : Context.SignedCharTy;
case NeonTypeFlags::Int16:
return Flags.isUnsigned() ? Context.UnsignedShortTy : Context.ShortTy;
case NeonTypeFlags::Int32:
return Flags.isUnsigned() ? Context.UnsignedIntTy : Context.IntTy;
case NeonTypeFlags::Int64:
return Flags.isUnsigned() ? Context.UnsignedLongLongTy : Context.LongLongTy;
case NeonTypeFlags::Poly8:
return Context.SignedCharTy;
case NeonTypeFlags::Poly16:
return Context.ShortTy;
case NeonTypeFlags::Float16:
return Context.UnsignedShortTy;
case NeonTypeFlags::Float32:
return Context.FloatTy;
}
llvm_unreachable("Invalid NeonTypeFlag!");
}
bool Sema::CheckARMBuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall) {
llvm::APSInt Result;
unsigned mask = 0;
unsigned TV = 0;
int PtrArgNum = -1;
bool HasConstPtr = false;
switch (BuiltinID) {
#define GET_NEON_OVERLOAD_CHECK
#include "clang/Basic/arm_neon.inc"
#undef GET_NEON_OVERLOAD_CHECK
}
// For NEON intrinsics which are overloaded on vector element type, validate
// the immediate which specifies which variant to emit.
unsigned ImmArg = TheCall->getNumArgs()-1;
if (mask) {
if (SemaBuiltinConstantArg(TheCall, ImmArg, Result))
return true;
TV = Result.getLimitedValue(64);
if ((TV > 63) || (mask & (1 << TV)) == 0)
return Diag(TheCall->getLocStart(), diag::err_invalid_neon_type_code)
<< TheCall->getArg(ImmArg)->getSourceRange();
}
if (PtrArgNum >= 0) {
// Check that pointer arguments have the specified type.
Expr *Arg = TheCall->getArg(PtrArgNum);
if (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(Arg))
Arg = ICE->getSubExpr();
ExprResult RHS = DefaultFunctionArrayLvalueConversion(Arg);
QualType RHSTy = RHS.get()->getType();
QualType EltTy = getNeonEltType(NeonTypeFlags(TV), Context);
if (HasConstPtr)
EltTy = EltTy.withConst();
QualType LHSTy = Context.getPointerType(EltTy);
AssignConvertType ConvTy;
ConvTy = CheckSingleAssignmentConstraints(LHSTy, RHS);
if (RHS.isInvalid())
return true;
if (DiagnoseAssignmentResult(ConvTy, Arg->getLocStart(), LHSTy, RHSTy,
RHS.get(), AA_Assigning))
return true;
}
// For NEON intrinsics which take an immediate value as part of the
// instruction, range check them here.
unsigned i = 0, l = 0, u = 0;
switch (BuiltinID) {
default: return false;
case ARM::BI__builtin_arm_ssat: i = 1; l = 1; u = 31; break;
case ARM::BI__builtin_arm_usat: i = 1; u = 31; break;
case ARM::BI__builtin_arm_vcvtr_f:
case ARM::BI__builtin_arm_vcvtr_d: i = 1; u = 1; break;
#define GET_NEON_IMMEDIATE_CHECK
#include "clang/Basic/arm_neon.inc"
#undef GET_NEON_IMMEDIATE_CHECK
};
// Check that the immediate argument is actually a constant.
if (SemaBuiltinConstantArg(TheCall, i, Result))
return true;
// Range check against the upper/lower values for this isntruction.
unsigned Val = Result.getZExtValue();
if (Val < l || Val > (u + l))
return Diag(TheCall->getLocStart(), diag::err_argument_invalid_range)
<< l << u+l << TheCall->getArg(i)->getSourceRange();
// FIXME: VFP Intrinsics should error if VFP not present.
return false;
}
/// Given a FunctionDecl's FormatAttr, attempts to populate the FomatStringInfo
/// parameter with the FormatAttr's correct format_idx and firstDataArg.
/// Returns true when the format fits the function and the FormatStringInfo has
/// been populated.
bool Sema::getFormatStringInfo(const FormatAttr *Format, bool IsCXXMember,
FormatStringInfo *FSI) {
FSI->HasVAListArg = Format->getFirstArg() == 0;
FSI->FormatIdx = Format->getFormatIdx() - 1;
FSI->FirstDataArg = FSI->HasVAListArg ? 0 : Format->getFirstArg() - 1;
// The way the format attribute works in GCC, the implicit this argument
// of member functions is counted. However, it doesn't appear in our own
// lists, so decrement format_idx in that case.
if (IsCXXMember) {
if(FSI->FormatIdx == 0)
return false;
--FSI->FormatIdx;
if (FSI->FirstDataArg != 0)
--FSI->FirstDataArg;
}
return true;
}
/// Handles the checks for format strings, non-POD arguments to vararg
/// functions, and NULL arguments passed to non-NULL parameters.
void Sema::checkCall(NamedDecl *FDecl, Expr **Args,
unsigned NumArgs,
unsigned NumProtoArgs,
bool IsMemberFunction,
SourceLocation Loc,
SourceRange Range,
VariadicCallType CallType) {
// FIXME: This mechanism should be abstracted to be less fragile and
// more efficient. For example, just map function ids to custom
// handlers.
// Printf and scanf checking.
bool HandledFormatString = false;
for (specific_attr_iterator<FormatAttr>
I = FDecl->specific_attr_begin<FormatAttr>(),
E = FDecl->specific_attr_end<FormatAttr>(); I != E ; ++I)
if (CheckFormatArguments(*I, Args, NumArgs, IsMemberFunction, Loc, Range))
HandledFormatString = true;
// Refuse POD arguments that weren't caught by the format string
// checks above.
if (!HandledFormatString && CallType != VariadicDoesNotApply)
for (unsigned ArgIdx = NumProtoArgs; ArgIdx < NumArgs; ++ArgIdx)
variadicArgumentPODCheck(Args[ArgIdx], CallType);
for (specific_attr_iterator<NonNullAttr>
I = FDecl->specific_attr_begin<NonNullAttr>(),
E = FDecl->specific_attr_end<NonNullAttr>(); I != E; ++I)
CheckNonNullArguments(*I, Args, Loc);
}
/// CheckConstructorCall - Check a constructor call for correctness and safety
/// properties not enforced by the C type system.
void Sema::CheckConstructorCall(FunctionDecl *FDecl, Expr **Args,
unsigned NumArgs,
const FunctionProtoType *Proto,
SourceLocation Loc) {
VariadicCallType CallType =
Proto->isVariadic() ? VariadicConstructor : VariadicDoesNotApply;
checkCall(FDecl, Args, NumArgs, Proto->getNumArgs(),
/*IsMemberFunction=*/true, Loc, SourceRange(), CallType);
}
/// CheckFunctionCall - Check a direct function call for various correctness
/// and safety properties not strictly enforced by the C type system.
bool Sema::CheckFunctionCall(FunctionDecl *FDecl, CallExpr *TheCall,
const FunctionProtoType *Proto) {
bool IsMemberFunction = isa<CXXMemberCallExpr>(TheCall);
VariadicCallType CallType = getVariadicCallType(FDecl, Proto,
TheCall->getCallee());
unsigned NumProtoArgs = Proto ? Proto->getNumArgs() : 0;
checkCall(FDecl, TheCall->getArgs(), TheCall->getNumArgs(), NumProtoArgs,
IsMemberFunction, TheCall->getRParenLoc(),
TheCall->getCallee()->getSourceRange(), CallType);
IdentifierInfo *FnInfo = FDecl->getIdentifier();
// None of the checks below are needed for functions that don't have
// simple names (e.g., C++ conversion functions).
if (!FnInfo)
return false;
unsigned CMId = FDecl->getMemoryFunctionKind();
if (CMId == 0)
return false;
// Handle memory setting and copying functions.
if (CMId == Builtin::BIstrlcpy || CMId == Builtin::BIstrlcat)
CheckStrlcpycatArguments(TheCall, FnInfo);
else if (CMId == Builtin::BIstrncat)
CheckStrncatArguments(TheCall, FnInfo);
else
CheckMemaccessArguments(TheCall, CMId, FnInfo);
return false;
}
bool Sema::CheckObjCMethodCall(ObjCMethodDecl *Method, SourceLocation lbrac,
Expr **Args, unsigned NumArgs) {
VariadicCallType CallType =
Method->isVariadic() ? VariadicMethod : VariadicDoesNotApply;
checkCall(Method, Args, NumArgs, Method->param_size(),
/*IsMemberFunction=*/false,
lbrac, Method->getSourceRange(), CallType);
return false;
}
bool Sema::CheckBlockCall(NamedDecl *NDecl, CallExpr *TheCall,
const FunctionProtoType *Proto) {
const VarDecl *V = dyn_cast<VarDecl>(NDecl);
if (!V)
return false;
QualType Ty = V->getType();
if (!Ty->isBlockPointerType())
return false;
VariadicCallType CallType =
Proto && Proto->isVariadic() ? VariadicBlock : VariadicDoesNotApply ;
unsigned NumProtoArgs = Proto ? Proto->getNumArgs() : 0;
checkCall(NDecl, TheCall->getArgs(), TheCall->getNumArgs(),
NumProtoArgs, /*IsMemberFunction=*/false,
TheCall->getRParenLoc(),
TheCall->getCallee()->getSourceRange(), CallType);
return false;
}
ExprResult Sema::SemaAtomicOpsOverloaded(ExprResult TheCallResult,
AtomicExpr::AtomicOp Op) {
CallExpr *TheCall = cast<CallExpr>(TheCallResult.get());
DeclRefExpr *DRE =cast<DeclRefExpr>(TheCall->getCallee()->IgnoreParenCasts());
// All these operations take one of the following forms:
enum {
// C __c11_atomic_init(A *, C)
Init,
// C __c11_atomic_load(A *, int)
Load,
// void __atomic_load(A *, CP, int)
Copy,
// C __c11_atomic_add(A *, M, int)
Arithmetic,
// C __atomic_exchange_n(A *, CP, int)
Xchg,
// void __atomic_exchange(A *, C *, CP, int)
GNUXchg,
// bool __c11_atomic_compare_exchange_strong(A *, C *, CP, int, int)
C11CmpXchg,
// bool __atomic_compare_exchange(A *, C *, CP, bool, int, int)
GNUCmpXchg
} Form = Init;
const unsigned NumArgs[] = { 2, 2, 3, 3, 3, 4, 5, 6 };
const unsigned NumVals[] = { 1, 0, 1, 1, 1, 2, 2, 3 };
// where:
// C is an appropriate type,
// A is volatile _Atomic(C) for __c11 builtins and is C for GNU builtins,
// CP is C for __c11 builtins and GNU _n builtins and is C * otherwise,
// M is C if C is an integer, and ptrdiff_t if C is a pointer, and
// the int parameters are for orderings.
assert(AtomicExpr::AO__c11_atomic_init == 0 &&
AtomicExpr::AO__c11_atomic_fetch_xor + 1 == AtomicExpr::AO__atomic_load
&& "need to update code for modified C11 atomics");
bool IsC11 = Op >= AtomicExpr::AO__c11_atomic_init &&
Op <= AtomicExpr::AO__c11_atomic_fetch_xor;
bool IsN = Op == AtomicExpr::AO__atomic_load_n ||
Op == AtomicExpr::AO__atomic_store_n ||
Op == AtomicExpr::AO__atomic_exchange_n ||
Op == AtomicExpr::AO__atomic_compare_exchange_n;
bool IsAddSub = false;
switch (Op) {
case AtomicExpr::AO__c11_atomic_init:
Form = Init;
break;
case AtomicExpr::AO__c11_atomic_load:
case AtomicExpr::AO__atomic_load_n:
Form = Load;
break;
case AtomicExpr::AO__c11_atomic_store:
case AtomicExpr::AO__atomic_load:
case AtomicExpr::AO__atomic_store:
case AtomicExpr::AO__atomic_store_n:
Form = Copy;
break;
case AtomicExpr::AO__c11_atomic_fetch_add:
case AtomicExpr::AO__c11_atomic_fetch_sub:
case AtomicExpr::AO__atomic_fetch_add:
case AtomicExpr::AO__atomic_fetch_sub:
case AtomicExpr::AO__atomic_add_fetch:
case AtomicExpr::AO__atomic_sub_fetch:
IsAddSub = true;
// Fall through.
case AtomicExpr::AO__c11_atomic_fetch_and:
case AtomicExpr::AO__c11_atomic_fetch_or:
case AtomicExpr::AO__c11_atomic_fetch_xor:
case AtomicExpr::AO__atomic_fetch_and:
case AtomicExpr::AO__atomic_fetch_or:
case AtomicExpr::AO__atomic_fetch_xor:
case AtomicExpr::AO__atomic_fetch_nand:
case AtomicExpr::AO__atomic_and_fetch:
case AtomicExpr::AO__atomic_or_fetch:
case AtomicExpr::AO__atomic_xor_fetch:
case AtomicExpr::AO__atomic_nand_fetch:
Form = Arithmetic;
break;
case AtomicExpr::AO__c11_atomic_exchange:
case AtomicExpr::AO__atomic_exchange_n:
Form = Xchg;
break;
case AtomicExpr::AO__atomic_exchange:
Form = GNUXchg;
break;
case AtomicExpr::AO__c11_atomic_compare_exchange_strong:
case AtomicExpr::AO__c11_atomic_compare_exchange_weak:
Form = C11CmpXchg;
break;
case AtomicExpr::AO__atomic_compare_exchange:
case AtomicExpr::AO__atomic_compare_exchange_n:
Form = GNUCmpXchg;
break;
}
// Check we have the right number of arguments.
if (TheCall->getNumArgs() < NumArgs[Form]) {
Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args)
<< 0 << NumArgs[Form] << TheCall->getNumArgs()
<< TheCall->getCallee()->getSourceRange();
return ExprError();
} else if (TheCall->getNumArgs() > NumArgs[Form]) {
Diag(TheCall->getArg(NumArgs[Form])->getLocStart(),
diag::err_typecheck_call_too_many_args)
<< 0 << NumArgs[Form] << TheCall->getNumArgs()
<< TheCall->getCallee()->getSourceRange();
return ExprError();
}
// Inspect the first argument of the atomic operation.
Expr *Ptr = TheCall->getArg(0);
Ptr = DefaultFunctionArrayLvalueConversion(Ptr).get();
const PointerType *pointerType = Ptr->getType()->getAs<PointerType>();
if (!pointerType) {
Diag(DRE->getLocStart(), diag::err_atomic_builtin_must_be_pointer)
<< Ptr->getType() << Ptr->getSourceRange();
return ExprError();
}
// For a __c11 builtin, this should be a pointer to an _Atomic type.
QualType AtomTy = pointerType->getPointeeType(); // 'A'
QualType ValType = AtomTy; // 'C'
if (IsC11) {
if (!AtomTy->isAtomicType()) {
Diag(DRE->getLocStart(), diag::err_atomic_op_needs_atomic)
<< Ptr->getType() << Ptr->getSourceRange();
return ExprError();
}
ValType = AtomTy->getAs<AtomicType>()->getValueType();
}
// For an arithmetic operation, the implied arithmetic must be well-formed.
if (Form == Arithmetic) {
// gcc does not enforce these rules for GNU atomics, but we do so for sanity.
if (IsAddSub && !ValType->isIntegerType() && !ValType->isPointerType()) {
Diag(DRE->getLocStart(), diag::err_atomic_op_needs_atomic_int_or_ptr)
<< IsC11 << Ptr->getType() << Ptr->getSourceRange();
return ExprError();
}
if (!IsAddSub && !ValType->isIntegerType()) {
Diag(DRE->getLocStart(), diag::err_atomic_op_bitwise_needs_atomic_int)
<< IsC11 << Ptr->getType() << Ptr->getSourceRange();
return ExprError();
}
} else if (IsN && !ValType->isIntegerType() && !ValType->isPointerType()) {
// For __atomic_*_n operations, the value type must be a scalar integral or
// pointer type which is 1, 2, 4, 8 or 16 bytes in length.
Diag(DRE->getLocStart(), diag::err_atomic_op_needs_atomic_int_or_ptr)
<< IsC11 << Ptr->getType() << Ptr->getSourceRange();
return ExprError();
}
if (!IsC11 && !AtomTy.isTriviallyCopyableType(Context)) {
// For GNU atomics, require a trivially-copyable type. This is not part of
// the GNU atomics specification, but we enforce it for sanity.
Diag(DRE->getLocStart(), diag::err_atomic_op_needs_trivial_copy)
<< Ptr->getType() << Ptr->getSourceRange();
return ExprError();
}
// FIXME: For any builtin other than a load, the ValType must not be
// const-qualified.
switch (ValType.getObjCLifetime()) {
case Qualifiers::OCL_None:
case Qualifiers::OCL_ExplicitNone:
// okay
break;
case Qualifiers::OCL_Weak:
case Qualifiers::OCL_Strong:
case Qualifiers::OCL_Autoreleasing:
// FIXME: Can this happen? By this point, ValType should be known
// to be trivially copyable.
Diag(DRE->getLocStart(), diag::err_arc_atomic_ownership)
<< ValType << Ptr->getSourceRange();
return ExprError();
}
QualType ResultType = ValType;
if (Form == Copy || Form == GNUXchg || Form == Init)
ResultType = Context.VoidTy;
else if (Form == C11CmpXchg || Form == GNUCmpXchg)
ResultType = Context.BoolTy;
// The type of a parameter passed 'by value'. In the GNU atomics, such
// arguments are actually passed as pointers.
QualType ByValType = ValType; // 'CP'
if (!IsC11 && !IsN)
ByValType = Ptr->getType();
// The first argument --- the pointer --- has a fixed type; we
// deduce the types of the rest of the arguments accordingly. Walk
// the remaining arguments, converting them to the deduced value type.
for (unsigned i = 1; i != NumArgs[Form]; ++i) {
QualType Ty;
if (i < NumVals[Form] + 1) {
switch (i) {
case 1:
// The second argument is the non-atomic operand. For arithmetic, this
// is always passed by value, and for a compare_exchange it is always
// passed by address. For the rest, GNU uses by-address and C11 uses
// by-value.
assert(Form != Load);
if (Form == Init || (Form == Arithmetic && ValType->isIntegerType()))
Ty = ValType;
else if (Form == Copy || Form == Xchg)
Ty = ByValType;
else if (Form == Arithmetic)
Ty = Context.getPointerDiffType();
else
Ty = Context.getPointerType(ValType.getUnqualifiedType());
break;
case 2:
// The third argument to compare_exchange / GNU exchange is a
// (pointer to a) desired value.
Ty = ByValType;
break;
case 3:
// The fourth argument to GNU compare_exchange is a 'weak' flag.
Ty = Context.BoolTy;
break;
}
} else {
// The order(s) are always converted to int.
Ty = Context.IntTy;
}
InitializedEntity Entity =
InitializedEntity::InitializeParameter(Context, Ty, false);
ExprResult Arg = TheCall->getArg(i);
Arg = PerformCopyInitialization(Entity, SourceLocation(), Arg);
if (Arg.isInvalid())
return true;
TheCall->setArg(i, Arg.get());
}
// Permute the arguments into a 'consistent' order.
SmallVector<Expr*, 5> SubExprs;
SubExprs.push_back(Ptr);
switch (Form) {
case Init:
// Note, AtomicExpr::getVal1() has a special case for this atomic.
SubExprs.push_back(TheCall->getArg(1)); // Val1
break;
case Load:
SubExprs.push_back(TheCall->getArg(1)); // Order
break;
case Copy:
case Arithmetic:
case Xchg:
SubExprs.push_back(TheCall->getArg(2)); // Order
SubExprs.push_back(TheCall->getArg(1)); // Val1
break;
case GNUXchg:
// Note, AtomicExpr::getVal2() has a special case for this atomic.
SubExprs.push_back(TheCall->getArg(3)); // Order
SubExprs.push_back(TheCall->getArg(1)); // Val1
SubExprs.push_back(TheCall->getArg(2)); // Val2
break;
case C11CmpXchg:
SubExprs.push_back(TheCall->getArg(3)); // Order
SubExprs.push_back(TheCall->getArg(1)); // Val1
SubExprs.push_back(TheCall->getArg(4)); // OrderFail
SubExprs.push_back(TheCall->getArg(2)); // Val2
break;
case GNUCmpXchg:
SubExprs.push_back(TheCall->getArg(4)); // Order
SubExprs.push_back(TheCall->getArg(1)); // Val1
SubExprs.push_back(TheCall->getArg(5)); // OrderFail
SubExprs.push_back(TheCall->getArg(2)); // Val2
SubExprs.push_back(TheCall->getArg(3)); // Weak
break;
}
return Owned(new (Context) AtomicExpr(TheCall->getCallee()->getLocStart(),
SubExprs.data(), SubExprs.size(),
ResultType, Op,
TheCall->getRParenLoc()));
}
/// checkBuiltinArgument - Given a call to a builtin function, perform
/// normal type-checking on the given argument, updating the call in
/// place. This is useful when a builtin function requires custom
/// type-checking for some of its arguments but not necessarily all of
/// them.
///
/// Returns true on error.
static bool checkBuiltinArgument(Sema &S, CallExpr *E, unsigned ArgIndex) {
FunctionDecl *Fn = E->getDirectCallee();
assert(Fn && "builtin call without direct callee!");
ParmVarDecl *Param = Fn->getParamDecl(ArgIndex);
InitializedEntity Entity =
InitializedEntity::InitializeParameter(S.Context, Param);
ExprResult Arg = E->getArg(0);
Arg = S.PerformCopyInitialization(Entity, SourceLocation(), Arg);
if (Arg.isInvalid())
return true;
E->setArg(ArgIndex, Arg.take());
return false;
}
/// SemaBuiltinAtomicOverloaded - We have a call to a function like
/// __sync_fetch_and_add, which is an overloaded function based on the pointer
/// type of its first argument. The main ActOnCallExpr routines have already
/// promoted the types of arguments because all of these calls are prototyped as
/// void(...).
///
/// This function goes through and does final semantic checking for these
/// builtins,
ExprResult
Sema::SemaBuiltinAtomicOverloaded(ExprResult TheCallResult) {
CallExpr *TheCall = (CallExpr *)TheCallResult.get();
DeclRefExpr *DRE =cast<DeclRefExpr>(TheCall->getCallee()->IgnoreParenCasts());
FunctionDecl *FDecl = cast<FunctionDecl>(DRE->getDecl());
// Ensure that we have at least one argument to do type inference from.
if (TheCall->getNumArgs() < 1) {
Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args_at_least)
<< 0 << 1 << TheCall->getNumArgs()
<< TheCall->getCallee()->getSourceRange();
return ExprError();
}
// Inspect the first argument of the atomic builtin. This should always be
// a pointer type, whose element is an integral scalar or pointer type.
// Because it is a pointer type, we don't have to worry about any implicit
// casts here.
// FIXME: We don't allow floating point scalars as input.
Expr *FirstArg = TheCall->getArg(0);
ExprResult FirstArgResult = DefaultFunctionArrayLvalueConversion(FirstArg);
if (FirstArgResult.isInvalid())
return ExprError();
FirstArg = FirstArgResult.take();
TheCall->setArg(0, FirstArg);
const PointerType *pointerType = FirstArg->getType()->getAs<PointerType>();
if (!pointerType) {
Diag(DRE->getLocStart(), diag::err_atomic_builtin_must_be_pointer)
<< FirstArg->getType() << FirstArg->getSourceRange();
return ExprError();
}
QualType ValType = pointerType->getPointeeType();
if (!ValType->isIntegerType() && !ValType->isAnyPointerType() &&
!ValType->isBlockPointerType()) {
Diag(DRE->getLocStart(), diag::err_atomic_builtin_must_be_pointer_intptr)
<< FirstArg->getType() << FirstArg->getSourceRange();
return ExprError();
}
switch (ValType.getObjCLifetime()) {
case Qualifiers::OCL_None:
case Qualifiers::OCL_ExplicitNone:
// okay
break;
case Qualifiers::OCL_Weak:
case Qualifiers::OCL_Strong:
case Qualifiers::OCL_Autoreleasing:
Diag(DRE->getLocStart(), diag::err_arc_atomic_ownership)
<< ValType << FirstArg->getSourceRange();
return ExprError();
}
// Strip any qualifiers off ValType.
ValType = ValType.getUnqualifiedType();
// The majority of builtins return a value, but a few have special return
// types, so allow them to override appropriately below.
QualType ResultType = ValType;
// We need to figure out which concrete builtin this maps onto. For example,
// __sync_fetch_and_add with a 2 byte object turns into
// __sync_fetch_and_add_2.
#define BUILTIN_ROW(x) \
{ Builtin::BI##x##_1, Builtin::BI##x##_2, Builtin::BI##x##_4, \
Builtin::BI##x##_8, Builtin::BI##x##_16 }
static const unsigned BuiltinIndices[][5] = {
BUILTIN_ROW(__sync_fetch_and_add),
BUILTIN_ROW(__sync_fetch_and_sub),
BUILTIN_ROW(__sync_fetch_and_or),
BUILTIN_ROW(__sync_fetch_and_and),
BUILTIN_ROW(__sync_fetch_and_xor),
BUILTIN_ROW(__sync_add_and_fetch),
BUILTIN_ROW(__sync_sub_and_fetch),
BUILTIN_ROW(__sync_and_and_fetch),
BUILTIN_ROW(__sync_or_and_fetch),
BUILTIN_ROW(__sync_xor_and_fetch),
BUILTIN_ROW(__sync_val_compare_and_swap),
BUILTIN_ROW(__sync_bool_compare_and_swap),
BUILTIN_ROW(__sync_lock_test_and_set),
BUILTIN_ROW(__sync_lock_release),
BUILTIN_ROW(__sync_swap)
};
#undef BUILTIN_ROW
// Determine the index of the size.
unsigned SizeIndex;
switch (Context.getTypeSizeInChars(ValType).getQuantity()) {
case 1: SizeIndex = 0; break;
case 2: SizeIndex = 1; break;
case 4: SizeIndex = 2; break;
case 8: SizeIndex = 3; break;
case 16: SizeIndex = 4; break;
default:
Diag(DRE->getLocStart(), diag::err_atomic_builtin_pointer_size)
<< FirstArg->getType() << FirstArg->getSourceRange();
return ExprError();
}
// Each of these builtins has one pointer argument, followed by some number of
// values (0, 1 or 2) followed by a potentially empty varags list of stuff
// that we ignore. Find out which row of BuiltinIndices to read from as well
// as the number of fixed args.
unsigned BuiltinID = FDecl->getBuiltinID();
unsigned BuiltinIndex, NumFixed = 1;
switch (BuiltinID) {
default: llvm_unreachable("Unknown overloaded atomic builtin!");
case Builtin::BI__sync_fetch_and_add:
case Builtin::BI__sync_fetch_and_add_1:
case Builtin::BI__sync_fetch_and_add_2:
case Builtin::BI__sync_fetch_and_add_4:
case Builtin::BI__sync_fetch_and_add_8:
case Builtin::BI__sync_fetch_and_add_16:
BuiltinIndex = 0;
break;
case Builtin::BI__sync_fetch_and_sub:
case Builtin::BI__sync_fetch_and_sub_1:
case Builtin::BI__sync_fetch_and_sub_2:
case Builtin::BI__sync_fetch_and_sub_4:
case Builtin::BI__sync_fetch_and_sub_8:
case Builtin::BI__sync_fetch_and_sub_16:
BuiltinIndex = 1;
break;
case Builtin::BI__sync_fetch_and_or:
case Builtin::BI__sync_fetch_and_or_1:
case Builtin::BI__sync_fetch_and_or_2:
case Builtin::BI__sync_fetch_and_or_4:
case Builtin::BI__sync_fetch_and_or_8:
case Builtin::BI__sync_fetch_and_or_16:
BuiltinIndex = 2;
break;
case Builtin::BI__sync_fetch_and_and:
case Builtin::BI__sync_fetch_and_and_1:
case Builtin::BI__sync_fetch_and_and_2:
case Builtin::BI__sync_fetch_and_and_4:
case Builtin::BI__sync_fetch_and_and_8:
case Builtin::BI__sync_fetch_and_and_16:
BuiltinIndex = 3;
break;
case Builtin::BI__sync_fetch_and_xor:
case Builtin::BI__sync_fetch_and_xor_1:
case Builtin::BI__sync_fetch_and_xor_2:
case Builtin::BI__sync_fetch_and_xor_4:
case Builtin::BI__sync_fetch_and_xor_8:
case Builtin::BI__sync_fetch_and_xor_16:
BuiltinIndex = 4;
break;
case Builtin::BI__sync_add_and_fetch:
case Builtin::BI__sync_add_and_fetch_1:
case Builtin::BI__sync_add_and_fetch_2:
case Builtin::BI__sync_add_and_fetch_4:
case Builtin::BI__sync_add_and_fetch_8:
case Builtin::BI__sync_add_and_fetch_16:
BuiltinIndex = 5;
break;
case Builtin::BI__sync_sub_and_fetch:
case Builtin::BI__sync_sub_and_fetch_1:
case Builtin::BI__sync_sub_and_fetch_2:
case Builtin::BI__sync_sub_and_fetch_4:
case Builtin::BI__sync_sub_and_fetch_8:
case Builtin::BI__sync_sub_and_fetch_16:
BuiltinIndex = 6;
break;
case Builtin::BI__sync_and_and_fetch:
case Builtin::BI__sync_and_and_fetch_1:
case Builtin::BI__sync_and_and_fetch_2:
case Builtin::BI__sync_and_and_fetch_4:
case Builtin::BI__sync_and_and_fetch_8:
case Builtin::BI__sync_and_and_fetch_16:
BuiltinIndex = 7;
break;
case Builtin::BI__sync_or_and_fetch:
case Builtin::BI__sync_or_and_fetch_1:
case Builtin::BI__sync_or_and_fetch_2:
case Builtin::BI__sync_or_and_fetch_4:
case Builtin::BI__sync_or_and_fetch_8:
case Builtin::BI__sync_or_and_fetch_16:
BuiltinIndex = 8;
break;
case Builtin::BI__sync_xor_and_fetch:
case Builtin::BI__sync_xor_and_fetch_1:
case Builtin::BI__sync_xor_and_fetch_2:
case Builtin::BI__sync_xor_and_fetch_4:
case Builtin::BI__sync_xor_and_fetch_8:
case Builtin::BI__sync_xor_and_fetch_16:
BuiltinIndex = 9;
break;
case Builtin::BI__sync_val_compare_and_swap:
case Builtin::BI__sync_val_compare_and_swap_1:
case Builtin::BI__sync_val_compare_and_swap_2:
case Builtin::BI__sync_val_compare_and_swap_4:
case Builtin::BI__sync_val_compare_and_swap_8:
case Builtin::BI__sync_val_compare_and_swap_16:
BuiltinIndex = 10;
NumFixed = 2;
break;
case Builtin::BI__sync_bool_compare_and_swap:
case Builtin::BI__sync_bool_compare_and_swap_1:
case Builtin::BI__sync_bool_compare_and_swap_2:
case Builtin::BI__sync_bool_compare_and_swap_4:
case Builtin::BI__sync_bool_compare_and_swap_8:
case Builtin::BI__sync_bool_compare_and_swap_16:
BuiltinIndex = 11;
NumFixed = 2;
ResultType = Context.BoolTy;
break;
case Builtin::BI__sync_lock_test_and_set:
case Builtin::BI__sync_lock_test_and_set_1:
case Builtin::BI__sync_lock_test_and_set_2:
case Builtin::BI__sync_lock_test_and_set_4:
case Builtin::BI__sync_lock_test_and_set_8:
case Builtin::BI__sync_lock_test_and_set_16:
BuiltinIndex = 12;
break;
case Builtin::BI__sync_lock_release:
case Builtin::BI__sync_lock_release_1:
case Builtin::BI__sync_lock_release_2:
case Builtin::BI__sync_lock_release_4:
case Builtin::BI__sync_lock_release_8:
case Builtin::BI__sync_lock_release_16:
BuiltinIndex = 13;
NumFixed = 0;
ResultType = Context.VoidTy;
break;
case Builtin::BI__sync_swap:
case Builtin::BI__sync_swap_1:
case Builtin::BI__sync_swap_2:
case Builtin::BI__sync_swap_4:
case Builtin::BI__sync_swap_8:
case Builtin::BI__sync_swap_16:
BuiltinIndex = 14;
break;
}
// Now that we know how many fixed arguments we expect, first check that we
// have at least that many.
if (TheCall->getNumArgs() < 1+NumFixed) {
Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args_at_least)
<< 0 << 1+NumFixed << TheCall->getNumArgs()
<< TheCall->getCallee()->getSourceRange();
return ExprError();
}
// Get the decl for the concrete builtin from this, we can tell what the
// concrete integer type we should convert to is.
unsigned NewBuiltinID = BuiltinIndices[BuiltinIndex][SizeIndex];
const char *NewBuiltinName = Context.BuiltinInfo.GetName(NewBuiltinID);
IdentifierInfo *NewBuiltinII = PP.getIdentifierInfo(NewBuiltinName);
FunctionDecl *NewBuiltinDecl =
cast<FunctionDecl>(LazilyCreateBuiltin(NewBuiltinII, NewBuiltinID,
TUScope, false, DRE->getLocStart()));
// The first argument --- the pointer --- has a fixed type; we
// deduce the types of the rest of the arguments accordingly. Walk
// the remaining arguments, converting them to the deduced value type.
for (unsigned i = 0; i != NumFixed; ++i) {
ExprResult Arg = TheCall->getArg(i+1);
// GCC does an implicit conversion to the pointer or integer ValType. This
// can fail in some cases (1i -> int**), check for this error case now.
// Initialize the argument.
InitializedEntity Entity = InitializedEntity::InitializeParameter(Context,
ValType, /*consume*/ false);
Arg = PerformCopyInitialization(Entity, SourceLocation(), Arg);
if (Arg.isInvalid())
return ExprError();
// Okay, we have something that *can* be converted to the right type. Check
// to see if there is a potentially weird extension going on here. This can
// happen when you do an atomic operation on something like an char* and
// pass in 42. The 42 gets converted to char. This is even more strange
// for things like 45.123 -> char, etc.
// FIXME: Do this check.
TheCall->setArg(i+1, Arg.take());
}
ASTContext& Context = this->getASTContext();
// Create a new DeclRefExpr to refer to the new decl.
DeclRefExpr* NewDRE = DeclRefExpr::Create(
Context,
DRE->getQualifierLoc(),
SourceLocation(),
NewBuiltinDecl,
/*enclosing*/ false,
DRE->getLocation(),
NewBuiltinDecl->getType(),
DRE->getValueKind());
// Set the callee in the CallExpr.
// FIXME: This leaks the original parens and implicit casts.
ExprResult PromotedCall = UsualUnaryConversions(NewDRE);
if (PromotedCall.isInvalid())
return ExprError();
TheCall->setCallee(PromotedCall.take());
// Change the result type of the call to match the original value type. This
// is arbitrary, but the codegen for these builtins ins design to handle it
// gracefully.
TheCall->setType(ResultType);
return move(TheCallResult);
}
/// CheckObjCString - Checks that the argument to the builtin
/// CFString constructor is correct
/// Note: It might also make sense to do the UTF-16 conversion here (would
/// simplify the backend).
bool Sema::CheckObjCString(Expr *Arg) {
Arg = Arg->IgnoreParenCasts();
StringLiteral *Literal = dyn_cast<StringLiteral>(Arg);
if (!Literal || !Literal->isAscii()) {
Diag(Arg->getLocStart(), diag::err_cfstring_literal_not_string_constant)
<< Arg->getSourceRange();
return true;
}
if (Literal->containsNonAsciiOrNull()) {
StringRef String = Literal->getString();
unsigned NumBytes = String.size();
SmallVector<UTF16, 128> ToBuf(NumBytes);
const UTF8 *FromPtr = (UTF8 *)String.data();
UTF16 *ToPtr = &ToBuf[0];
ConversionResult Result = ConvertUTF8toUTF16(&FromPtr, FromPtr + NumBytes,
&ToPtr, ToPtr + NumBytes,
strictConversion);
// Check for conversion failure.
if (Result != conversionOK)
Diag(Arg->getLocStart(),
diag::warn_cfstring_truncated) << Arg->getSourceRange();
}
return false;
}
/// SemaBuiltinVAStart - Check the arguments to __builtin_va_start for validity.
/// Emit an error and return true on failure, return false on success.
bool Sema::SemaBuiltinVAStart(CallExpr *TheCall) {
Expr *Fn = TheCall->getCallee();
if (TheCall->getNumArgs() > 2) {
Diag(TheCall->getArg(2)->getLocStart(),
diag::err_typecheck_call_too_many_args)
<< 0 /*function call*/ << 2 << TheCall->getNumArgs()
<< Fn->getSourceRange()
<< SourceRange(TheCall->getArg(2)->getLocStart(),
(*(TheCall->arg_end()-1))->getLocEnd());
return true;
}
if (TheCall->getNumArgs() < 2) {
return Diag(TheCall->getLocEnd(),
diag::err_typecheck_call_too_few_args_at_least)
<< 0 /*function call*/ << 2 << TheCall->getNumArgs();
}
// Type-check the first argument normally.
if (checkBuiltinArgument(*this, TheCall, 0))
return true;
// Determine whether the current function is variadic or not.
BlockScopeInfo *CurBlock = getCurBlock();
bool isVariadic;
if (CurBlock)
isVariadic = CurBlock->TheDecl->isVariadic();
else if (FunctionDecl *FD = getCurFunctionDecl())
isVariadic = FD->isVariadic();
else
isVariadic = getCurMethodDecl()->isVariadic();
if (!isVariadic) {
Diag(Fn->getLocStart(), diag::err_va_start_used_in_non_variadic_function);
return true;
}
// Verify that the second argument to the builtin is the last argument of the
// current function or method.
bool SecondArgIsLastNamedArgument = false;
const Expr *Arg = TheCall->getArg(1)->IgnoreParenCasts();
if (const DeclRefExpr *DR = dyn_cast<DeclRefExpr>(Arg)) {
if (const ParmVarDecl *PV = dyn_cast<ParmVarDecl>(DR->getDecl())) {
// FIXME: This isn't correct for methods (results in bogus warning).
// Get the last formal in the current function.
const ParmVarDecl *LastArg;
if (CurBlock)
LastArg = *(CurBlock->TheDecl->param_end()-1);
else if (FunctionDecl *FD = getCurFunctionDecl())
LastArg = *(FD->param_end()-1);
else
LastArg = *(getCurMethodDecl()->param_end()-1);
SecondArgIsLastNamedArgument = PV == LastArg;
}
}
if (!SecondArgIsLastNamedArgument)
Diag(TheCall->getArg(1)->getLocStart(),
diag::warn_second_parameter_of_va_start_not_last_named_argument);
return false;
}
/// SemaBuiltinUnorderedCompare - Handle functions like __builtin_isgreater and
/// friends. This is declared to take (...), so we have to check everything.
bool Sema::SemaBuiltinUnorderedCompare(CallExpr *TheCall) {
if (TheCall->getNumArgs() < 2)
return Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args)
<< 0 << 2 << TheCall->getNumArgs()/*function call*/;
if (TheCall->getNumArgs() > 2)
return Diag(TheCall->getArg(2)->getLocStart(),
diag::err_typecheck_call_too_many_args)
<< 0 /*function call*/ << 2 << TheCall->getNumArgs()
<< SourceRange(TheCall->getArg(2)->getLocStart(),
(*(TheCall->arg_end()-1))->getLocEnd());
ExprResult OrigArg0 = TheCall->getArg(0);
ExprResult OrigArg1 = TheCall->getArg(1);
// Do standard promotions between the two arguments, returning their common
// type.
QualType Res = UsualArithmeticConversions(OrigArg0, OrigArg1, false);
if (OrigArg0.isInvalid() || OrigArg1.isInvalid())
return true;
// Make sure any conversions are pushed back into the call; this is
// type safe since unordered compare builtins are declared as "_Bool
// foo(...)".
TheCall->setArg(0, OrigArg0.get());
TheCall->setArg(1, OrigArg1.get());
if (OrigArg0.get()->isTypeDependent() || OrigArg1.get()->isTypeDependent())
return false;
// If the common type isn't a real floating type, then the arguments were
// invalid for this operation.
if (Res.isNull() || !Res->isRealFloatingType())
return Diag(OrigArg0.get()->getLocStart(),
diag::err_typecheck_call_invalid_ordered_compare)
<< OrigArg0.get()->getType() << OrigArg1.get()->getType()
<< SourceRange(OrigArg0.get()->getLocStart(), OrigArg1.get()->getLocEnd());
return false;
}
/// SemaBuiltinSemaBuiltinFPClassification - Handle functions like
/// __builtin_isnan and friends. This is declared to take (...), so we have
/// to check everything. We expect the last argument to be a floating point
/// value.
bool Sema::SemaBuiltinFPClassification(CallExpr *TheCall, unsigned NumArgs) {
if (TheCall->getNumArgs() < NumArgs)
return Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args)
<< 0 << NumArgs << TheCall->getNumArgs()/*function call*/;
if (TheCall->getNumArgs() > NumArgs)
return Diag(TheCall->getArg(NumArgs)->getLocStart(),
diag::err_typecheck_call_too_many_args)
<< 0 /*function call*/ << NumArgs << TheCall->getNumArgs()
<< SourceRange(TheCall->getArg(NumArgs)->getLocStart(),
(*(TheCall->arg_end()-1))->getLocEnd());
Expr *OrigArg = TheCall->getArg(NumArgs-1);
if (OrigArg->isTypeDependent())
return false;
// This operation requires a non-_Complex floating-point number.
if (!OrigArg->getType()->isRealFloatingType())
return Diag(OrigArg->getLocStart(),
diag::err_typecheck_call_invalid_unary_fp)
<< OrigArg->getType() << OrigArg->getSourceRange();
// If this is an implicit conversion from float -> double, remove it.
if (ImplicitCastExpr *Cast = dyn_cast<ImplicitCastExpr>(OrigArg)) {
Expr *CastArg = Cast->getSubExpr();
if (CastArg->getType()->isSpecificBuiltinType(BuiltinType::Float)) {
assert(Cast->getType()->isSpecificBuiltinType(BuiltinType::Double) &&
"promotion from float to double is the only expected cast here");
Cast->setSubExpr(0);
TheCall->setArg(NumArgs-1, CastArg);
}
}
return false;
}
/// SemaBuiltinShuffleVector - Handle __builtin_shufflevector.
// This is declared to take (...), so we have to check everything.
ExprResult Sema::SemaBuiltinShuffleVector(CallExpr *TheCall) {
if (TheCall->getNumArgs() < 2)
return ExprError(Diag(TheCall->getLocEnd(),
diag::err_typecheck_call_too_few_args_at_least)
<< 0 /*function call*/ << 2 << TheCall->getNumArgs()
<< TheCall->getSourceRange());
// Determine which of the following types of shufflevector we're checking:
// 1) unary, vector mask: (lhs, mask)
// 2) binary, vector mask: (lhs, rhs, mask)
// 3) binary, scalar mask: (lhs, rhs, index, ..., index)
QualType resType = TheCall->getArg(0)->getType();
unsigned numElements = 0;
if (!TheCall->getArg(0)->isTypeDependent() &&
!TheCall->getArg(1)->isTypeDependent()) {
QualType LHSType = TheCall->getArg(0)->getType();
QualType RHSType = TheCall->getArg(1)->getType();
if (!LHSType->isVectorType() || !RHSType->isVectorType()) {
Diag(TheCall->getLocStart(), diag::err_shufflevector_non_vector)
<< SourceRange(TheCall->getArg(0)->getLocStart(),
TheCall->getArg(1)->getLocEnd());
return ExprError();
}
numElements = LHSType->getAs<VectorType>()->getNumElements();
unsigned numResElements = TheCall->getNumArgs() - 2;
// Check to see if we have a call with 2 vector arguments, the unary shuffle
// with mask. If so, verify that RHS is an integer vector type with the
// same number of elts as lhs.
if (TheCall->getNumArgs() == 2) {
if (!RHSType->hasIntegerRepresentation() ||
RHSType->getAs<VectorType>()->getNumElements() != numElements)
Diag(TheCall->getLocStart(), diag::err_shufflevector_incompatible_vector)
<< SourceRange(TheCall->getArg(1)->getLocStart(),
TheCall->getArg(1)->getLocEnd());
numResElements = numElements;
}
else if (!Context.hasSameUnqualifiedType(LHSType, RHSType)) {
Diag(TheCall->getLocStart(), diag::err_shufflevector_incompatible_vector)
<< SourceRange(TheCall->getArg(0)->getLocStart(),
TheCall->getArg(1)->getLocEnd());
return ExprError();
} else if (numElements != numResElements) {
QualType eltType = LHSType->getAs<VectorType>()->getElementType();
resType = Context.getVectorType(eltType, numResElements,
VectorType::GenericVector);
}
}
for (unsigned i = 2; i < TheCall->getNumArgs(); i++) {
if (TheCall->getArg(i)->isTypeDependent() ||
TheCall->getArg(i)->isValueDependent())
continue;
llvm::APSInt Result(32);
if (!TheCall->getArg(i)->isIntegerConstantExpr(Result, Context))
return ExprError(Diag(TheCall->getLocStart(),
diag::err_shufflevector_nonconstant_argument)
<< TheCall->getArg(i)->getSourceRange());
if (Result.getActiveBits() > 64 || Result.getZExtValue() >= numElements*2)
return ExprError(Diag(TheCall->getLocStart(),
diag::err_shufflevector_argument_too_large)
<< TheCall->getArg(i)->getSourceRange());
}
SmallVector<Expr*, 32> exprs;
for (unsigned i = 0, e = TheCall->getNumArgs(); i != e; i++) {
exprs.push_back(TheCall->getArg(i));
TheCall->setArg(i, 0);
}
return Owned(new (Context) ShuffleVectorExpr(Context, exprs.begin(),
exprs.size(), resType,
TheCall->getCallee()->getLocStart(),
TheCall->getRParenLoc()));
}
/// SemaBuiltinPrefetch - Handle __builtin_prefetch.
// This is declared to take (const void*, ...) and can take two
// optional constant int args.
bool Sema::SemaBuiltinPrefetch(CallExpr *TheCall) {
unsigned NumArgs = TheCall->getNumArgs();
if (NumArgs > 3)
return Diag(TheCall->getLocEnd(),
diag::err_typecheck_call_too_many_args_at_most)
<< 0 /*function call*/ << 3 << NumArgs
<< TheCall->getSourceRange();
// Argument 0 is checked for us and the remaining arguments must be
// constant integers.
for (unsigned i = 1; i != NumArgs; ++i) {
Expr *Arg = TheCall->getArg(i);
llvm::APSInt Result;
if (SemaBuiltinConstantArg(TheCall, i, Result))
return true;
// FIXME: gcc issues a warning and rewrites these to 0. These
// seems especially odd for the third argument since the default
// is 3.
if (i == 1) {
if (Result.getLimitedValue() > 1)
return Diag(TheCall->getLocStart(), diag::err_argument_invalid_range)
<< "0" << "1" << Arg->getSourceRange();
} else {
if (Result.getLimitedValue() > 3)
return Diag(TheCall->getLocStart(), diag::err_argument_invalid_range)
<< "0" << "3" << Arg->getSourceRange();
}
}
return false;
}
/// SemaBuiltinConstantArg - Handle a check if argument ArgNum of CallExpr
/// TheCall is a constant expression.
bool Sema::SemaBuiltinConstantArg(CallExpr *TheCall, int ArgNum,
llvm::APSInt &Result) {
Expr *Arg = TheCall->getArg(ArgNum);
DeclRefExpr *DRE =cast<DeclRefExpr>(TheCall->getCallee()->IgnoreParenCasts());
FunctionDecl *FDecl = cast<FunctionDecl>(DRE->getDecl());
if (Arg->isTypeDependent() || Arg->isValueDependent()) return false;
if (!Arg->isIntegerConstantExpr(Result, Context))
return Diag(TheCall->getLocStart(), diag::err_constant_integer_arg_type)
<< FDecl->getDeclName() << Arg->getSourceRange();
return false;
}
/// SemaBuiltinObjectSize - Handle __builtin_object_size(void *ptr,
/// int type). This simply type checks that type is one of the defined
/// constants (0-3).
// For compatibility check 0-3, llvm only handles 0 and 2.
bool Sema::SemaBuiltinObjectSize(CallExpr *TheCall) {
llvm::APSInt Result;
// Check constant-ness first.
if (SemaBuiltinConstantArg(TheCall, 1, Result))
return true;
Expr *Arg = TheCall->getArg(1);
if (Result.getSExtValue() < 0 || Result.getSExtValue() > 3) {
return Diag(TheCall->getLocStart(), diag::err_argument_invalid_range)
<< "0" << "3" << SourceRange(Arg->getLocStart(), Arg->getLocEnd());
}
return false;
}
/// SemaBuiltinLongjmp - Handle __builtin_longjmp(void *env[5], int val).
/// This checks that val is a constant 1.
bool Sema::SemaBuiltinLongjmp(CallExpr *TheCall) {
Expr *Arg = TheCall->getArg(1);
llvm::APSInt Result;
// TODO: This is less than ideal. Overload this to take a value.
if (SemaBuiltinConstantArg(TheCall, 1, Result))
return true;
if (Result != 1)
return Diag(TheCall->getLocStart(), diag::err_builtin_longjmp_invalid_val)
<< SourceRange(Arg->getLocStart(), Arg->getLocEnd());
return false;
}
// Determine if an expression is a string literal or constant string.
// If this function returns false on the arguments to a function expecting a
// format string, we will usually need to emit a warning.
// True string literals are then checked by CheckFormatString.
Sema::StringLiteralCheckType
Sema::checkFormatStringExpr(const Expr *E, Expr **Args,
unsigned NumArgs, bool HasVAListArg,
unsigned format_idx, unsigned firstDataArg,
FormatStringType Type, bool inFunctionCall) {
tryAgain:
if (E->isTypeDependent() || E->isValueDependent())
return SLCT_NotALiteral;
E = E->IgnoreParenCasts();
if (E->isNullPointerConstant(Context, Expr::NPC_ValueDependentIsNotNull))
// Technically -Wformat-nonliteral does not warn about this case.
// The behavior of printf and friends in this case is implementation
// dependent. Ideally if the format string cannot be null then
// it should have a 'nonnull' attribute in the function prototype.
return SLCT_CheckedLiteral;
switch (E->getStmtClass()) {
case Stmt::BinaryConditionalOperatorClass:
case Stmt::ConditionalOperatorClass: {
// The expression is a literal if both sub-expressions were, and it was
// completely checked only if both sub-expressions were checked.
const AbstractConditionalOperator *C =
cast<AbstractConditionalOperator>(E);
StringLiteralCheckType Left =
checkFormatStringExpr(C->getTrueExpr(), Args, NumArgs,
HasVAListArg, format_idx, firstDataArg,
Type, inFunctionCall);
if (Left == SLCT_NotALiteral)
return SLCT_NotALiteral;
StringLiteralCheckType Right =
checkFormatStringExpr(C->getFalseExpr(), Args, NumArgs,
HasVAListArg, format_idx, firstDataArg,
Type, inFunctionCall);
return Left < Right ? Left : Right;
}
case Stmt::ImplicitCastExprClass: {
E = cast<ImplicitCastExpr>(E)->getSubExpr();
goto tryAgain;
}
case Stmt::OpaqueValueExprClass:
if (const Expr *src = cast<OpaqueValueExpr>(E)->getSourceExpr()) {
E = src;
goto tryAgain;
}
return SLCT_NotALiteral;
case Stmt::PredefinedExprClass:
// While __func__, etc., are technically not string literals, they
// cannot contain format specifiers and thus are not a security
// liability.
return SLCT_UncheckedLiteral;
case Stmt::DeclRefExprClass: {
const DeclRefExpr *DR = cast<DeclRefExpr>(E);
// As an exception, do not flag errors for variables binding to
// const string literals.
if (const VarDecl *VD = dyn_cast<VarDecl>(DR->getDecl())) {
bool isConstant = false;
QualType T = DR->getType();
if (const ArrayType *AT = Context.getAsArrayType(T)) {
isConstant = AT->getElementType().isConstant(Context);
} else if (const PointerType *PT = T->getAs<PointerType>()) {
isConstant = T.isConstant(Context) &&
PT->getPointeeType().isConstant(Context);
} else if (T->isObjCObjectPointerType()) {
// In ObjC, there is usually no "const ObjectPointer" type,
// so don't check if the pointee type is constant.
isConstant = T.isConstant(Context);
}
if (isConstant) {
if (const Expr *Init = VD->getAnyInitializer()) {
// Look through initializers like const char c[] = { "foo" }
if (const InitListExpr *InitList = dyn_cast<InitListExpr>(Init)) {
if (InitList->isStringLiteralInit())
Init = InitList->getInit(0)->IgnoreParenImpCasts();
}
return checkFormatStringExpr(Init, Args, NumArgs,
HasVAListArg, format_idx,
firstDataArg, Type,
/*inFunctionCall*/false);
}
}
// For vprintf* functions (i.e., HasVAListArg==true), we add a
// special check to see if the format string is a function parameter
// of the function calling the printf function. If the function
// has an attribute indicating it is a printf-like function, then we
// should suppress warnings concerning non-literals being used in a call
// to a vprintf function. For example:
//
// void
// logmessage(char const *fmt __attribute__ (format (printf, 1, 2)), ...){
// va_list ap;
// va_start(ap, fmt);
// vprintf(fmt, ap); // Do NOT emit a warning about "fmt".
// ...
//
if (HasVAListArg) {
if (const ParmVarDecl *PV = dyn_cast<ParmVarDecl>(VD)) {
if (const NamedDecl *ND = dyn_cast<NamedDecl>(PV->getDeclContext())) {
int PVIndex = PV->getFunctionScopeIndex() + 1;
for (specific_attr_iterator<FormatAttr>
i = ND->specific_attr_begin<FormatAttr>(),
e = ND->specific_attr_end<FormatAttr>(); i != e ; ++i) {
FormatAttr *PVFormat = *i;
// adjust for implicit parameter
if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(ND))
if (MD->isInstance())
++PVIndex;
// We also check if the formats are compatible.
// We can't pass a 'scanf' string to a 'printf' function.
if (PVIndex == PVFormat->getFormatIdx() &&
Type == GetFormatStringType(PVFormat))
return SLCT_UncheckedLiteral;
}
}
}
}
}
return SLCT_NotALiteral;
}
case Stmt::CallExprClass:
case Stmt::CXXMemberCallExprClass: {
const CallExpr *CE = cast<CallExpr>(E);
if (const NamedDecl *ND = dyn_cast_or_null<NamedDecl>(CE->getCalleeDecl())) {
if (const FormatArgAttr *FA = ND->getAttr<FormatArgAttr>()) {
unsigned ArgIndex = FA->getFormatIdx();
if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(ND))
if (MD->isInstance())
--ArgIndex;
const Expr *Arg = CE->getArg(ArgIndex - 1);
return checkFormatStringExpr(Arg, Args, NumArgs,
HasVAListArg, format_idx, firstDataArg,
Type, inFunctionCall);
} else if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(ND)) {
unsigned BuiltinID = FD->getBuiltinID();
if (BuiltinID == Builtin::BI__builtin___CFStringMakeConstantString ||
BuiltinID == Builtin::BI__builtin___NSStringMakeConstantString) {
const Expr *Arg = CE->getArg(0);
return checkFormatStringExpr(Arg, Args, NumArgs,
HasVAListArg, format_idx,
firstDataArg, Type, inFunctionCall);
}
}
}
return SLCT_NotALiteral;
}
case Stmt::ObjCStringLiteralClass:
case Stmt::StringLiteralClass: {
const StringLiteral *StrE = NULL;
if (const ObjCStringLiteral *ObjCFExpr = dyn_cast<ObjCStringLiteral>(E))
StrE = ObjCFExpr->getString();
else
StrE = cast<StringLiteral>(E);
if (StrE) {
CheckFormatString(StrE, E, Args, NumArgs, HasVAListArg, format_idx,
firstDataArg, Type, inFunctionCall);
return SLCT_CheckedLiteral;
}
return SLCT_NotALiteral;
}
default:
return SLCT_NotALiteral;
}
}
void
Sema::CheckNonNullArguments(const NonNullAttr *NonNull,
const Expr * const *ExprArgs,
SourceLocation CallSiteLoc) {
for (NonNullAttr::args_iterator i = NonNull->args_begin(),
e = NonNull->args_end();
i != e; ++i) {
const Expr *ArgExpr = ExprArgs[*i];
if (ArgExpr->isNullPointerConstant(Context,
Expr::NPC_ValueDependentIsNotNull))
Diag(CallSiteLoc, diag::warn_null_arg) << ArgExpr->getSourceRange();
}
}
Sema::FormatStringType Sema::GetFormatStringType(const FormatAttr *Format) {
return llvm::StringSwitch<FormatStringType>(Format->getType())
.Case("scanf", FST_Scanf)
.Cases("printf", "printf0", FST_Printf)
.Cases("NSString", "CFString", FST_NSString)
.Case("strftime", FST_Strftime)
.Case("strfmon", FST_Strfmon)
.Cases("kprintf", "cmn_err", "vcmn_err", "zcmn_err", FST_Kprintf)
.Default(FST_Unknown);
}
/// CheckPrintfScanfArguments - Check calls to printf and scanf (and similar
/// functions) for correct use of format strings.
/// Returns true if a format string has been fully checked.
bool Sema::CheckFormatArguments(const FormatAttr *Format, CallExpr *TheCall) {
bool IsCXXMember = isa<CXXMemberCallExpr>(TheCall);
return CheckFormatArguments(Format, TheCall->getArgs(),
TheCall->getNumArgs(),
IsCXXMember, TheCall->getRParenLoc(),
TheCall->getCallee()->getSourceRange());
}
bool Sema::CheckFormatArguments(const FormatAttr *Format, Expr **Args,
unsigned NumArgs, bool IsCXXMember,
SourceLocation Loc, SourceRange Range) {
FormatStringInfo FSI;
if (getFormatStringInfo(Format, IsCXXMember, &FSI))
return CheckFormatArguments(Args, NumArgs, FSI.HasVAListArg, FSI.FormatIdx,
FSI.FirstDataArg, GetFormatStringType(Format),
Loc, Range);
return false;
}
bool Sema::CheckFormatArguments(Expr **Args, unsigned NumArgs,
bool HasVAListArg, unsigned format_idx,
unsigned firstDataArg, FormatStringType Type,
SourceLocation Loc, SourceRange Range) {
// CHECK: printf/scanf-like function is called with no format string.
if (format_idx >= NumArgs) {
Diag(Loc, diag::warn_missing_format_string) << Range;
return false;
}
const Expr *OrigFormatExpr = Args[format_idx]->IgnoreParenCasts();
// CHECK: format string is not a string literal.
//
// Dynamically generated format strings are difficult to
// automatically vet at compile time. Requiring that format strings
// are string literals: (1) permits the checking of format strings by
// the compiler and thereby (2) can practically remove the source of
// many format string exploits.
// Format string can be either ObjC string (e.g. @"%d") or
// C string (e.g. "%d")
// ObjC string uses the same format specifiers as C string, so we can use
// the same format string checking logic for both ObjC and C strings.
StringLiteralCheckType CT =
checkFormatStringExpr(OrigFormatExpr, Args, NumArgs, HasVAListArg,
format_idx, firstDataArg, Type);
if (CT != SLCT_NotALiteral)
// Literal format string found, check done!
return CT == SLCT_CheckedLiteral;
// Strftime is particular as it always uses a single 'time' argument,
// so it is safe to pass a non-literal string.
if (Type == FST_Strftime)
return false;
// Do not emit diag when the string param is a macro expansion and the
// format is either NSString or CFString. This is a hack to prevent
// diag when using the NSLocalizedString and CFCopyLocalizedString macros
// which are usually used in place of NS and CF string literals.
if (Type == FST_NSString &&
SourceMgr.isInSystemMacro(Args[format_idx]->getLocStart()))
return false;
// If there are no arguments specified, warn with -Wformat-security, otherwise
// warn only with -Wformat-nonliteral.
if (NumArgs == format_idx+1)
Diag(Args[format_idx]->getLocStart(),
diag::warn_format_nonliteral_noargs)
<< OrigFormatExpr->getSourceRange();
else
Diag(Args[format_idx]->getLocStart(),
diag::warn_format_nonliteral)
<< OrigFormatExpr->getSourceRange();
return false;
}
namespace {
class CheckFormatHandler : public analyze_format_string::FormatStringHandler {
protected:
Sema &S;
const StringLiteral *FExpr;
const Expr *OrigFormatExpr;
const unsigned FirstDataArg;
const unsigned NumDataArgs;
const char *Beg; // Start of format string.
const bool HasVAListArg;
const Expr * const *Args;
const unsigned NumArgs;
unsigned FormatIdx;
llvm::BitVector CoveredArgs;
bool usesPositionalArgs;
bool atFirstArg;
bool inFunctionCall;
public:
CheckFormatHandler(Sema &s, const StringLiteral *fexpr,
const Expr *origFormatExpr, unsigned firstDataArg,
unsigned numDataArgs, const char *beg, bool hasVAListArg,
Expr **args, unsigned numArgs,
unsigned formatIdx, bool inFunctionCall)
: S(s), FExpr(fexpr), OrigFormatExpr(origFormatExpr),
FirstDataArg(firstDataArg), NumDataArgs(numDataArgs),
Beg(beg), HasVAListArg(hasVAListArg),
Args(args), NumArgs(numArgs), FormatIdx(formatIdx),
usesPositionalArgs(false), atFirstArg(true),
inFunctionCall(inFunctionCall) {
CoveredArgs.resize(numDataArgs);
CoveredArgs.reset();
}
void DoneProcessing();
void HandleIncompleteSpecifier(const char *startSpecifier,
unsigned specifierLen);
void HandleNonStandardLengthModifier(
const analyze_format_string::LengthModifier &LM,
const char *startSpecifier, unsigned specifierLen);
void HandleNonStandardConversionSpecifier(
const analyze_format_string::ConversionSpecifier &CS,
const char *startSpecifier, unsigned specifierLen);
void HandleNonStandardConversionSpecification(
const analyze_format_string::LengthModifier &LM,
const analyze_format_string::ConversionSpecifier &CS,
const char *startSpecifier, unsigned specifierLen);
virtual void HandlePosition(const char *startPos, unsigned posLen);
virtual void HandleInvalidPosition(const char *startSpecifier,
unsigned specifierLen,
analyze_format_string::PositionContext p);
virtual void HandleZeroPosition(const char *startPos, unsigned posLen);
void HandleNullChar(const char *nullCharacter);
template <typename Range>
static void EmitFormatDiagnostic(Sema &S, bool inFunctionCall,
const Expr *ArgumentExpr,
PartialDiagnostic PDiag,
SourceLocation StringLoc,
bool IsStringLocation, Range StringRange,
FixItHint Fixit = FixItHint());
protected:
bool HandleInvalidConversionSpecifier(unsigned argIndex, SourceLocation Loc,
const char *startSpec,
unsigned specifierLen,
const char *csStart, unsigned csLen);
void HandlePositionalNonpositionalArgs(SourceLocation Loc,
const char *startSpec,
unsigned specifierLen);
SourceRange getFormatStringRange();
CharSourceRange getSpecifierRange(const char *startSpecifier,
unsigned specifierLen);
SourceLocation getLocationOfByte(const char *x);
const Expr *getDataArg(unsigned i) const;
bool CheckNumArgs(const analyze_format_string::FormatSpecifier &FS,
const analyze_format_string::ConversionSpecifier &CS,
const char *startSpecifier, unsigned specifierLen,
unsigned argIndex);
template <typename Range>
void EmitFormatDiagnostic(PartialDiagnostic PDiag, SourceLocation StringLoc,
bool IsStringLocation, Range StringRange,
FixItHint Fixit = FixItHint());
void CheckPositionalAndNonpositionalArgs(
const analyze_format_string::FormatSpecifier *FS);
};
}
SourceRange CheckFormatHandler::getFormatStringRange() {
return OrigFormatExpr->getSourceRange();
}
CharSourceRange CheckFormatHandler::
getSpecifierRange(const char *startSpecifier, unsigned specifierLen) {
SourceLocation Start = getLocationOfByte(startSpecifier);
SourceLocation End = getLocationOfByte(startSpecifier + specifierLen - 1);
// Advance the end SourceLocation by one due to half-open ranges.
End = End.getLocWithOffset(1);
return CharSourceRange::getCharRange(Start, End);
}
SourceLocation CheckFormatHandler::getLocationOfByte(const char *x) {
return S.getLocationOfStringLiteralByte(FExpr, x - Beg);
}
void CheckFormatHandler::HandleIncompleteSpecifier(const char *startSpecifier,
unsigned specifierLen){
EmitFormatDiagnostic(S.PDiag(diag::warn_printf_incomplete_specifier),
getLocationOfByte(startSpecifier),
/*IsStringLocation*/true,
getSpecifierRange(startSpecifier, specifierLen));
}
void CheckFormatHandler::HandleNonStandardLengthModifier(
const analyze_format_string::LengthModifier &LM,
const char *startSpecifier, unsigned specifierLen) {
EmitFormatDiagnostic(S.PDiag(diag::warn_format_non_standard) << LM.toString()
<< 0,
getLocationOfByte(LM.getStart()),
/*IsStringLocation*/true,
getSpecifierRange(startSpecifier, specifierLen));
}
void CheckFormatHandler::HandleNonStandardConversionSpecifier(
const analyze_format_string::ConversionSpecifier &CS,
const char *startSpecifier, unsigned specifierLen) {
EmitFormatDiagnostic(S.PDiag(diag::warn_format_non_standard) << CS.toString()
<< 1,
getLocationOfByte(CS.getStart()),
/*IsStringLocation*/true,
getSpecifierRange(startSpecifier, specifierLen));
}
void CheckFormatHandler::HandleNonStandardConversionSpecification(
const analyze_format_string::LengthModifier &LM,
const analyze_format_string::ConversionSpecifier &CS,
const char *startSpecifier, unsigned specifierLen) {
EmitFormatDiagnostic(S.PDiag(diag::warn_format_non_standard_conversion_spec)
<< LM.toString() << CS.toString(),
getLocationOfByte(LM.getStart()),
/*IsStringLocation*/true,
getSpecifierRange(startSpecifier, specifierLen));
}
void CheckFormatHandler::HandlePosition(const char *startPos,
unsigned posLen) {
EmitFormatDiagnostic(S.PDiag(diag::warn_format_non_standard_positional_arg),
getLocationOfByte(startPos),
/*IsStringLocation*/true,
getSpecifierRange(startPos, posLen));
}
void
CheckFormatHandler::HandleInvalidPosition(const char *startPos, unsigned posLen,
analyze_format_string::PositionContext p) {
EmitFormatDiagnostic(S.PDiag(diag::warn_format_invalid_positional_specifier)
<< (unsigned) p,
getLocationOfByte(startPos), /*IsStringLocation*/true,
getSpecifierRange(startPos, posLen));
}
void CheckFormatHandler::HandleZeroPosition(const char *startPos,
unsigned posLen) {
EmitFormatDiagnostic(S.PDiag(diag::warn_format_zero_positional_specifier),
getLocationOfByte(startPos),
/*IsStringLocation*/true,
getSpecifierRange(startPos, posLen));
}
void CheckFormatHandler::HandleNullChar(const char *nullCharacter) {
if (!isa<ObjCStringLiteral>(OrigFormatExpr)) {
// The presence of a null character is likely an error.
EmitFormatDiagnostic(
S.PDiag(diag::warn_printf_format_string_contains_null_char),
getLocationOfByte(nullCharacter), /*IsStringLocation*/true,
getFormatStringRange());
}
}
const Expr *CheckFormatHandler::getDataArg(unsigned i) const {
return Args[FirstDataArg + i];
}
void CheckFormatHandler::DoneProcessing() {
// Does the number of data arguments exceed the number of
// format conversions in the format string?
if (!HasVAListArg) {
// Find any arguments that weren't covered.
CoveredArgs.flip();
signed notCoveredArg = CoveredArgs.find_first();
if (notCoveredArg >= 0) {
assert((unsigned)notCoveredArg < NumDataArgs);
SourceLocation Loc = getDataArg((unsigned) notCoveredArg)->getLocStart();
if (!S.getSourceManager().isInSystemMacro(Loc)) {
EmitFormatDiagnostic(S.PDiag(diag::warn_printf_data_arg_not_used),
Loc,
/*IsStringLocation*/false, getFormatStringRange());
}
}
}
}
bool
CheckFormatHandler::HandleInvalidConversionSpecifier(unsigned argIndex,
SourceLocation Loc,
const char *startSpec,
unsigned specifierLen,
const char *csStart,
unsigned csLen) {
bool keepGoing = true;
if (argIndex < NumDataArgs) {
// Consider the argument coverered, even though the specifier doesn't
// make sense.
CoveredArgs.set(argIndex);
}
else {
// If argIndex exceeds the number of data arguments we
// don't issue a warning because that is just a cascade of warnings (and
// they may have intended '%%' anyway). We don't want to continue processing
// the format string after this point, however, as we will like just get
// gibberish when trying to match arguments.
keepGoing = false;
}
EmitFormatDiagnostic(S.PDiag(diag::warn_format_invalid_conversion)
<< StringRef(csStart, csLen),
Loc, /*IsStringLocation*/true,
getSpecifierRange(startSpec, specifierLen));
return keepGoing;
}
void
CheckFormatHandler::HandlePositionalNonpositionalArgs(SourceLocation Loc,
const char *startSpec,
unsigned specifierLen) {
EmitFormatDiagnostic(
S.PDiag(diag::warn_format_mix_positional_nonpositional_args),
Loc, /*isStringLoc*/true, getSpecifierRange(startSpec, specifierLen));
}
bool
CheckFormatHandler::CheckNumArgs(
const analyze_format_string::FormatSpecifier &FS,
const analyze_format_string::ConversionSpecifier &CS,
const char *startSpecifier, unsigned specifierLen, unsigned argIndex) {
if (argIndex >= NumDataArgs) {
PartialDiagnostic PDiag = FS.usesPositionalArg()
? (S.PDiag(diag::warn_printf_positional_arg_exceeds_data_args)
<< (argIndex+1) << NumDataArgs)
: S.PDiag(diag::warn_printf_insufficient_data_args);
EmitFormatDiagnostic(
PDiag, getLocationOfByte(CS.getStart()), /*IsStringLocation*/true,
getSpecifierRange(startSpecifier, specifierLen));
return false;
}
return true;
}
template<typename Range>
void CheckFormatHandler::EmitFormatDiagnostic(PartialDiagnostic PDiag,
SourceLocation Loc,
bool IsStringLocation,
Range StringRange,
FixItHint FixIt) {
EmitFormatDiagnostic(S, inFunctionCall, Args[FormatIdx], PDiag,
Loc, IsStringLocation, StringRange, FixIt);
}
/// \brief If the format string is not within the funcion call, emit a note
/// so that the function call and string are in diagnostic messages.
///
/// \param inFunctionCall if true, the format string is within the function
/// call and only one diagnostic message will be produced. Otherwise, an
/// extra note will be emitted pointing to location of the format string.
///
/// \param ArgumentExpr the expression that is passed as the format string
/// argument in the function call. Used for getting locations when two
/// diagnostics are emitted.
///
/// \param PDiag the callee should already have provided any strings for the
/// diagnostic message. This function only adds locations and fixits
/// to diagnostics.
///
/// \param Loc primary location for diagnostic. If two diagnostics are
/// required, one will be at Loc and a new SourceLocation will be created for
/// the other one.
///
/// \param IsStringLocation if true, Loc points to the format string should be
/// used for the note. Otherwise, Loc points to the argument list and will
/// be used with PDiag.
///
/// \param StringRange some or all of the string to highlight. This is
/// templated so it can accept either a CharSourceRange or a SourceRange.
///
/// \param Fixit optional fix it hint for the format string.
template<typename Range>
void CheckFormatHandler::EmitFormatDiagnostic(Sema &S, bool InFunctionCall,
const Expr *ArgumentExpr,
PartialDiagnostic PDiag,
SourceLocation Loc,
bool IsStringLocation,
Range StringRange,
FixItHint FixIt) {
if (InFunctionCall)
S.Diag(Loc, PDiag) << StringRange << FixIt;
else {
S.Diag(IsStringLocation ? ArgumentExpr->getExprLoc() : Loc, PDiag)
<< ArgumentExpr->getSourceRange();
S.Diag(IsStringLocation ? Loc : StringRange.getBegin(),
diag::note_format_string_defined)
<< StringRange << FixIt;
}
}
//===--- CHECK: Printf format string checking ------------------------------===//
namespace {
class CheckPrintfHandler : public CheckFormatHandler {
bool ObjCContext;
public:
CheckPrintfHandler(Sema &s, const StringLiteral *fexpr,
const Expr *origFormatExpr, unsigned firstDataArg,
unsigned numDataArgs, bool isObjC,
const char *beg, bool hasVAListArg,
Expr **Args, unsigned NumArgs,
unsigned formatIdx, bool inFunctionCall)
: CheckFormatHandler(s, fexpr, origFormatExpr, firstDataArg,
numDataArgs, beg, hasVAListArg, Args, NumArgs,
formatIdx, inFunctionCall), ObjCContext(isObjC) {}
bool HandleInvalidPrintfConversionSpecifier(
const analyze_printf::PrintfSpecifier &FS,
const char *startSpecifier,
unsigned specifierLen);
bool HandlePrintfSpecifier(const analyze_printf::PrintfSpecifier &FS,
const char *startSpecifier,
unsigned specifierLen);
bool checkFormatExpr(const analyze_printf::PrintfSpecifier &FS,
const char *StartSpecifier,
unsigned SpecifierLen,
const Expr *E);
bool HandleAmount(const analyze_format_string::OptionalAmount &Amt, unsigned k,
const char *startSpecifier, unsigned specifierLen);
void HandleInvalidAmount(const analyze_printf::PrintfSpecifier &FS,
const analyze_printf::OptionalAmount &Amt,
unsigned type,
const char *startSpecifier, unsigned specifierLen);
void HandleFlag(const analyze_printf::PrintfSpecifier &FS,
const analyze_printf::OptionalFlag &flag,
const char *startSpecifier, unsigned specifierLen);
void HandleIgnoredFlag(const analyze_printf::PrintfSpecifier &FS,
const analyze_printf::OptionalFlag &ignoredFlag,
const analyze_printf::OptionalFlag &flag,
const char *startSpecifier, unsigned specifierLen);
bool checkForCStrMembers(const analyze_printf::ArgTypeResult &ATR,
const Expr *E, const CharSourceRange &CSR);
};
}
bool CheckPrintfHandler::HandleInvalidPrintfConversionSpecifier(
const analyze_printf::PrintfSpecifier &FS,
const char *startSpecifier,
unsigned specifierLen) {
const analyze_printf::PrintfConversionSpecifier &CS =
FS.getConversionSpecifier();
return HandleInvalidConversionSpecifier(FS.getArgIndex(),
getLocationOfByte(CS.getStart()),
startSpecifier, specifierLen,
CS.getStart(), CS.getLength());
}
bool CheckPrintfHandler::HandleAmount(
const analyze_format_string::OptionalAmount &Amt,
unsigned k, const char *startSpecifier,
unsigned specifierLen) {
if (Amt.hasDataArgument()) {
if (!HasVAListArg) {
unsigned argIndex = Amt.getArgIndex();
if (argIndex >= NumDataArgs) {
EmitFormatDiagnostic(S.PDiag(diag::warn_printf_asterisk_missing_arg)
<< k,
getLocationOfByte(Amt.getStart()),
/*IsStringLocation*/true,
getSpecifierRange(startSpecifier, specifierLen));
// Don't do any more checking. We will just emit
// spurious errors.
return false;
}
// Type check the data argument. It should be an 'int'.
// Although not in conformance with C99, we also allow the argument to be
// an 'unsigned int' as that is a reasonably safe case. GCC also
// doesn't emit a warning for that case.
CoveredArgs.set(argIndex);
const Expr *Arg = getDataArg(argIndex);
QualType T = Arg->getType();
const analyze_printf::ArgTypeResult &ATR = Amt.getArgType(S.Context);
assert(ATR.isValid());
if (!ATR.matchesType(S.Context, T)) {
EmitFormatDiagnostic(S.PDiag(diag::warn_printf_asterisk_wrong_type)
<< k << ATR.getRepresentativeTypeName(S.Context)
<< T << Arg->getSourceRange(),
getLocationOfByte(Amt.getStart()),
/*IsStringLocation*/true,
getSpecifierRange(startSpecifier, specifierLen));
// Don't do any more checking. We will just emit
// spurious errors.
return false;
}
}
}
return true;
}
void CheckPrintfHandler::HandleInvalidAmount(
const analyze_printf::PrintfSpecifier &FS,
const analyze_printf::OptionalAmount &Amt,
unsigned type,
const char *startSpecifier,
unsigned specifierLen) {
const analyze_printf::PrintfConversionSpecifier &CS =
FS.getConversionSpecifier();
FixItHint fixit =
Amt.getHowSpecified() == analyze_printf::OptionalAmount::Constant
? FixItHint::CreateRemoval(getSpecifierRange(Amt.getStart(),
Amt.getConstantLength()))
: FixItHint();
EmitFormatDiagnostic(S.PDiag(diag::warn_printf_nonsensical_optional_amount)
<< type << CS.toString(),
getLocationOfByte(Amt.getStart()),
/*IsStringLocation*/true,
getSpecifierRange(startSpecifier, specifierLen),
fixit);
}
void CheckPrintfHandler::HandleFlag(const analyze_printf::PrintfSpecifier &FS,
const analyze_printf::OptionalFlag &flag,
const char *startSpecifier,
unsigned specifierLen) {
// Warn about pointless flag with a fixit removal.
const analyze_printf::PrintfConversionSpecifier &CS =
FS.getConversionSpecifier();
EmitFormatDiagnostic(S.PDiag(diag::warn_printf_nonsensical_flag)
<< flag.toString() << CS.toString(),
getLocationOfByte(flag.getPosition()),
/*IsStringLocation*/true,
getSpecifierRange(startSpecifier, specifierLen),
FixItHint::CreateRemoval(
getSpecifierRange(flag.getPosition(), 1)));
}
void CheckPrintfHandler::HandleIgnoredFlag(
const analyze_printf::PrintfSpecifier &FS,
const analyze_printf::OptionalFlag &ignoredFlag,
const analyze_printf::OptionalFlag &flag,
const char *startSpecifier,
unsigned specifierLen) {
// Warn about ignored flag with a fixit removal.
EmitFormatDiagnostic(S.PDiag(diag::warn_printf_ignored_flag)
<< ignoredFlag.toString() << flag.toString(),
getLocationOfByte(ignoredFlag.getPosition()),
/*IsStringLocation*/true,
getSpecifierRange(startSpecifier, specifierLen),
FixItHint::CreateRemoval(
getSpecifierRange(ignoredFlag.getPosition(), 1)));
}
// Determines if the specified is a C++ class or struct containing
// a member with the specified name and kind (e.g. a CXXMethodDecl named
// "c_str()").
template<typename MemberKind>
static llvm::SmallPtrSet<MemberKind*, 1>
CXXRecordMembersNamed(StringRef Name, Sema &S, QualType Ty) {
const RecordType *RT = Ty->getAs<RecordType>();
llvm::SmallPtrSet<MemberKind*, 1> Results;
if (!RT)
return Results;
const CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(RT->getDecl());
if (!RD)
return Results;
LookupResult R(S, &S.PP.getIdentifierTable().get(Name), SourceLocation(),
Sema::LookupMemberName);
// We just need to include all members of the right kind turned up by the
// filter, at this point.
if (S.LookupQualifiedName(R, RT->getDecl()))
for (LookupResult::iterator I = R.begin(), E = R.end(); I != E; ++I) {
NamedDecl *decl = (*I)->getUnderlyingDecl();
if (MemberKind *FK = dyn_cast<MemberKind>(decl))
Results.insert(FK);
}
return Results;
}
// Check if a (w)string was passed when a (w)char* was needed, and offer a
// better diagnostic if so. ATR is assumed to be valid.
// Returns true when a c_str() conversion method is found.
bool CheckPrintfHandler::checkForCStrMembers(
const analyze_printf::ArgTypeResult &ATR, const Expr *E,
const CharSourceRange &CSR) {
typedef llvm::SmallPtrSet<CXXMethodDecl*, 1> MethodSet;
MethodSet Results =
CXXRecordMembersNamed<CXXMethodDecl>("c_str", S, E->getType());
for (MethodSet::iterator MI = Results.begin(), ME = Results.end();
MI != ME; ++MI) {
const CXXMethodDecl *Method = *MI;
if (Method->getNumParams() == 0 &&
ATR.matchesType(S.Context, Method->getResultType())) {
// FIXME: Suggest parens if the expression needs them.
SourceLocation EndLoc =
S.getPreprocessor().getLocForEndOfToken(E->getLocEnd());
S.Diag(E->getLocStart(), diag::note_printf_c_str)
<< "c_str()"
<< FixItHint::CreateInsertion(EndLoc, ".c_str()");
return true;
}
}
return false;
}
bool
CheckPrintfHandler::HandlePrintfSpecifier(const analyze_printf::PrintfSpecifier
&FS,
const char *startSpecifier,
unsigned specifierLen) {
using namespace analyze_format_string;
using namespace analyze_printf;
const PrintfConversionSpecifier &CS = FS.getConversionSpecifier();
if (FS.consumesDataArgument()) {
if (atFirstArg) {
atFirstArg = false;
usesPositionalArgs = FS.usesPositionalArg();
}
else if (usesPositionalArgs != FS.usesPositionalArg()) {
HandlePositionalNonpositionalArgs(getLocationOfByte(CS.getStart()),
startSpecifier, specifierLen);
return false;
}
}
// First check if the field width, precision, and conversion specifier
// have matching data arguments.
if (!HandleAmount(FS.getFieldWidth(), /* field width */ 0,
startSpecifier, specifierLen)) {
return false;
}
if (!HandleAmount(FS.getPrecision(), /* precision */ 1,
startSpecifier, specifierLen)) {
return false;
}
if (!CS.consumesDataArgument()) {
// FIXME: Technically specifying a precision or field width here
// makes no sense. Worth issuing a warning at some point.
return true;
}
// Consume the argument.
unsigned argIndex = FS.getArgIndex();
if (argIndex < NumDataArgs) {
// The check to see if the argIndex is valid will come later.
// We set the bit here because we may exit early from this
// function if we encounter some other error.
CoveredArgs.set(argIndex);
}
// Check for using an Objective-C specific conversion specifier
// in a non-ObjC literal.
if (!ObjCContext && CS.isObjCArg()) {
return HandleInvalidPrintfConversionSpecifier(FS, startSpecifier,
specifierLen);
}
// Check for invalid use of field width
if (!FS.hasValidFieldWidth()) {
HandleInvalidAmount(FS, FS.getFieldWidth(), /* field width */ 0,
startSpecifier, specifierLen);
}
// Check for invalid use of precision
if (!FS.hasValidPrecision()) {
HandleInvalidAmount(FS, FS.getPrecision(), /* precision */ 1,
startSpecifier, specifierLen);
}
// Check each flag does not conflict with any other component.
if (!FS.hasValidThousandsGroupingPrefix())
HandleFlag(FS, FS.hasThousandsGrouping(), startSpecifier, specifierLen);
if (!FS.hasValidLeadingZeros())
HandleFlag(FS, FS.hasLeadingZeros(), startSpecifier, specifierLen);
if (!FS.hasValidPlusPrefix())
HandleFlag(FS, FS.hasPlusPrefix(), startSpecifier, specifierLen);
if (!FS.hasValidSpacePrefix())
HandleFlag(FS, FS.hasSpacePrefix(), startSpecifier, specifierLen);
if (!FS.hasValidAlternativeForm())
HandleFlag(FS, FS.hasAlternativeForm(), startSpecifier, specifierLen);
if (!FS.hasValidLeftJustified())
HandleFlag(FS, FS.isLeftJustified(), startSpecifier, specifierLen);
// Check that flags are not ignored by another flag
if (FS.hasSpacePrefix() && FS.hasPlusPrefix()) // ' ' ignored by '+'
HandleIgnoredFlag(FS, FS.hasSpacePrefix(), FS.hasPlusPrefix(),
startSpecifier, specifierLen);
if (FS.hasLeadingZeros() && FS.isLeftJustified()) // '0' ignored by '-'
HandleIgnoredFlag(FS, FS.hasLeadingZeros(), FS.isLeftJustified(),
startSpecifier, specifierLen);
// Check the length modifier is valid with the given conversion specifier.
const LengthModifier &LM = FS.getLengthModifier();
if (!FS.hasValidLengthModifier())
EmitFormatDiagnostic(S.PDiag(diag::warn_format_nonsensical_length)
<< LM.toString() << CS.toString(),
getLocationOfByte(LM.getStart()),
/*IsStringLocation*/true,
getSpecifierRange(startSpecifier, specifierLen),
FixItHint::CreateRemoval(
getSpecifierRange(LM.getStart(),
LM.getLength())));
if (!FS.hasStandardLengthModifier())
HandleNonStandardLengthModifier(LM, startSpecifier, specifierLen);
if (!FS.hasStandardConversionSpecifier(S.getLangOpts()))
HandleNonStandardConversionSpecifier(CS, startSpecifier, specifierLen);
if (!FS.hasStandardLengthConversionCombination())
HandleNonStandardConversionSpecification(LM, CS, startSpecifier,
specifierLen);
// Are we using '%n'?
if (CS.getKind() == ConversionSpecifier::nArg) {
// Issue a warning about this being a possible security issue.
EmitFormatDiagnostic(S.PDiag(diag::warn_printf_write_back),
getLocationOfByte(CS.getStart()),
/*IsStringLocation*/true,
getSpecifierRange(startSpecifier, specifierLen));
// Continue checking the other format specifiers.
return true;
}
// The remaining checks depend on the data arguments.
if (HasVAListArg)
return true;
if (!CheckNumArgs(FS, CS, startSpecifier, specifierLen, argIndex))
return false;
return checkFormatExpr(FS, startSpecifier, specifierLen,
getDataArg(argIndex));
}
bool
CheckPrintfHandler::checkFormatExpr(const analyze_printf::PrintfSpecifier &FS,
const char *StartSpecifier,
unsigned SpecifierLen,
const Expr *E) {
using namespace analyze_format_string;
using namespace analyze_printf;
// Now type check the data expression that matches the
// format specifier.
const analyze_printf::ArgTypeResult &ATR = FS.getArgType(S.Context,
ObjCContext);
if (ATR.isValid() && !ATR.matchesType(S.Context, E->getType())) {
// Look through argument promotions for our error message's reported type.
// This includes the integral and floating promotions, but excludes array
// and function pointer decay; seeing that an argument intended to be a
// string has type 'char [6]' is probably more confusing than 'char *'.
if (const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(E)) {
if (ICE->getCastKind() == CK_IntegralCast ||
ICE->getCastKind() == CK_FloatingCast) {
E = ICE->getSubExpr();
// Check if we didn't match because of an implicit cast from a 'char'
// or 'short' to an 'int'. This is done because printf is a varargs
// function.
if (ICE->getType() == S.Context.IntTy ||
ICE->getType() == S.Context.UnsignedIntTy) {
// All further checking is done on the subexpression.
if (ATR.matchesType(S.Context, E->getType()))
return true;
}
}
}
// We may be able to offer a FixItHint if it is a supported type.
PrintfSpecifier fixedFS = FS;
bool success = fixedFS.fixType(E->getType(), S.getLangOpts(),
S.Context, ObjCContext);
if (success) {
// Get the fix string from the fixed format specifier
SmallString<16> buf;
llvm::raw_svector_ostream os(buf);
fixedFS.toString(os);
EmitFormatDiagnostic(
S.PDiag(diag::warn_printf_conversion_argument_type_mismatch)
<< ATR.getRepresentativeTypeName(S.Context) << E->getType()
<< E->getSourceRange(),
E->getLocStart(),
/*IsStringLocation*/false,
getSpecifierRange(StartSpecifier, SpecifierLen),
FixItHint::CreateReplacement(
getSpecifierRange(StartSpecifier, SpecifierLen),
os.str()));
} else {
const CharSourceRange &CSR = getSpecifierRange(StartSpecifier,
SpecifierLen);
// Since the warning for passing non-POD types to variadic functions
// was deferred until now, we emit a warning for non-POD
// arguments here.
if (S.isValidVarArgType(E->getType()) == Sema::VAK_Invalid) {
EmitFormatDiagnostic(
S.PDiag(diag::warn_non_pod_vararg_with_format_string)
<< S.getLangOpts().CPlusPlus0x
<< E->getType()
<< ATR.getRepresentativeTypeName(S.Context)
<< CSR
<< E->getSourceRange(),
E->getLocStart(), /*IsStringLocation*/false, CSR);
checkForCStrMembers(ATR, E, CSR);
} else
EmitFormatDiagnostic(
S.PDiag(diag::warn_printf_conversion_argument_type_mismatch)
<< ATR.getRepresentativeTypeName(S.Context) << E->getType()
<< CSR
<< E->getSourceRange(),
E->getLocStart(), /*IsStringLocation*/false, CSR);
}
}
return true;
}
//===--- CHECK: Scanf format string checking ------------------------------===//
namespace {
class CheckScanfHandler : public CheckFormatHandler {
public:
CheckScanfHandler(Sema &s, const StringLiteral *fexpr,
const Expr *origFormatExpr, unsigned firstDataArg,
unsigned numDataArgs, const char *beg, bool hasVAListArg,
Expr **Args, unsigned NumArgs,
unsigned formatIdx, bool inFunctionCall)
: CheckFormatHandler(s, fexpr, origFormatExpr, firstDataArg,
numDataArgs, beg, hasVAListArg,
Args, NumArgs, formatIdx, inFunctionCall) {}
bool HandleScanfSpecifier(const analyze_scanf::ScanfSpecifier &FS,
const char *startSpecifier,
unsigned specifierLen);
bool HandleInvalidScanfConversionSpecifier(
const analyze_scanf::ScanfSpecifier &FS,
const char *startSpecifier,
unsigned specifierLen);
void HandleIncompleteScanList(const char *start, const char *end);
};
}
void CheckScanfHandler::HandleIncompleteScanList(const char *start,
const char *end) {
EmitFormatDiagnostic(S.PDiag(diag::warn_scanf_scanlist_incomplete),
getLocationOfByte(end), /*IsStringLocation*/true,
getSpecifierRange(start, end - start));
}
bool CheckScanfHandler::HandleInvalidScanfConversionSpecifier(
const analyze_scanf::ScanfSpecifier &FS,
const char *startSpecifier,
unsigned specifierLen) {
const analyze_scanf::ScanfConversionSpecifier &CS =
FS.getConversionSpecifier();
return HandleInvalidConversionSpecifier(FS.getArgIndex(),
getLocationOfByte(CS.getStart()),
startSpecifier, specifierLen,
CS.getStart(), CS.getLength());
}
bool CheckScanfHandler::HandleScanfSpecifier(
const analyze_scanf::ScanfSpecifier &FS,
const char *startSpecifier,
unsigned specifierLen) {
using namespace analyze_scanf;
using namespace analyze_format_string;
const ScanfConversionSpecifier &CS = FS.getConversionSpecifier();
// Handle case where '%' and '*' don't consume an argument. These shouldn't
// be used to decide if we are using positional arguments consistently.
if (FS.consumesDataArgument()) {
if (atFirstArg) {
atFirstArg = false;
usesPositionalArgs = FS.usesPositionalArg();
}
else if (usesPositionalArgs != FS.usesPositionalArg()) {
HandlePositionalNonpositionalArgs(getLocationOfByte(CS.getStart()),
startSpecifier, specifierLen);
return false;
}
}
// Check if the field with is non-zero.
const OptionalAmount &Amt = FS.getFieldWidth();
if (Amt.getHowSpecified() == OptionalAmount::Constant) {
if (Amt.getConstantAmount() == 0) {
const CharSourceRange &R = getSpecifierRange(Amt.getStart(),
Amt.getConstantLength());
EmitFormatDiagnostic(S.PDiag(diag::warn_scanf_nonzero_width),
getLocationOfByte(Amt.getStart()),
/*IsStringLocation*/true, R,
FixItHint::CreateRemoval(R));
}
}
if (!FS.consumesDataArgument()) {
// FIXME: Technically specifying a precision or field width here
// makes no sense. Worth issuing a warning at some point.
return true;
}
// Consume the argument.
unsigned argIndex = FS.getArgIndex();
if (argIndex < NumDataArgs) {
// The check to see if the argIndex is valid will come later.
// We set the bit here because we may exit early from this
// function if we encounter some other error.
CoveredArgs.set(argIndex);
}
// Check the length modifier is valid with the given conversion specifier.
const LengthModifier &LM = FS.getLengthModifier();
if (!FS.hasValidLengthModifier()) {
const CharSourceRange &R = getSpecifierRange(LM.getStart(), LM.getLength());
EmitFormatDiagnostic(S.PDiag(diag::warn_format_nonsensical_length)
<< LM.toString() << CS.toString()
<< getSpecifierRange(startSpecifier, specifierLen),
getLocationOfByte(LM.getStart()),
/*IsStringLocation*/true, R,
FixItHint::CreateRemoval(R));
}
if (!FS.hasStandardLengthModifier())
HandleNonStandardLengthModifier(LM, startSpecifier, specifierLen);
if (!FS.hasStandardConversionSpecifier(S.getLangOpts()))
HandleNonStandardConversionSpecifier(CS, startSpecifier, specifierLen);
if (!FS.hasStandardLengthConversionCombination())
HandleNonStandardConversionSpecification(LM, CS, startSpecifier,
specifierLen);
// The remaining checks depend on the data arguments.
if (HasVAListArg)
return true;
if (!CheckNumArgs(FS, CS, startSpecifier, specifierLen, argIndex))
return false;
// Check that the argument type matches the format specifier.
const Expr *Ex = getDataArg(argIndex);
const analyze_scanf::ScanfArgTypeResult &ATR = FS.getArgType(S.Context);
if (ATR.isValid() && !ATR.matchesType(S.Context, Ex->getType())) {
ScanfSpecifier fixedFS = FS;
bool success = fixedFS.fixType(Ex->getType(), S.getLangOpts(),
S.Context);
if (success) {
// Get the fix string from the fixed format specifier.
SmallString<128> buf;
llvm::raw_svector_ostream os(buf);
fixedFS.toString(os);
EmitFormatDiagnostic(
S.PDiag(diag::warn_printf_conversion_argument_type_mismatch)
<< ATR.getRepresentativeTypeName(S.Context) << Ex->getType()
<< Ex->getSourceRange(),
Ex->getLocStart(),
/*IsStringLocation*/false,
getSpecifierRange(startSpecifier, specifierLen),
FixItHint::CreateReplacement(
getSpecifierRange(startSpecifier, specifierLen),
os.str()));
} else {
EmitFormatDiagnostic(
S.PDiag(diag::warn_printf_conversion_argument_type_mismatch)
<< ATR.getRepresentativeTypeName(S.Context) << Ex->getType()
<< Ex->getSourceRange(),
Ex->getLocStart(),
/*IsStringLocation*/false,
getSpecifierRange(startSpecifier, specifierLen));
}
}
return true;
}
void Sema::CheckFormatString(const StringLiteral *FExpr,
const Expr *OrigFormatExpr,
Expr **Args, unsigned NumArgs,
bool HasVAListArg, unsigned format_idx,
unsigned firstDataArg, FormatStringType Type,
bool inFunctionCall) {
// CHECK: is the format string a wide literal?
if (!FExpr->isAscii() && !FExpr->isUTF8()) {
CheckFormatHandler::EmitFormatDiagnostic(
*this, inFunctionCall, Args[format_idx],
PDiag(diag::warn_format_string_is_wide_literal), FExpr->getLocStart(),
/*IsStringLocation*/true, OrigFormatExpr->getSourceRange());
return;
}
// Str - The format string. NOTE: this is NOT null-terminated!
StringRef StrRef = FExpr->getString();
const char *Str = StrRef.data();
unsigned StrLen = StrRef.size();
const unsigned numDataArgs = NumArgs - firstDataArg;
// CHECK: empty format string?
if (StrLen == 0 && numDataArgs > 0) {
CheckFormatHandler::EmitFormatDiagnostic(
*this, inFunctionCall, Args[format_idx],
PDiag(diag::warn_empty_format_string), FExpr->getLocStart(),
/*IsStringLocation*/true, OrigFormatExpr->getSourceRange());
return;
}
if (Type == FST_Printf || Type == FST_NSString) {
CheckPrintfHandler H(*this, FExpr, OrigFormatExpr, firstDataArg,
numDataArgs, (Type == FST_NSString),
Str, HasVAListArg, Args, NumArgs, format_idx,
inFunctionCall);
if (!analyze_format_string::ParsePrintfString(H, Str, Str + StrLen,
getLangOpts()))
H.DoneProcessing();
} else if (Type == FST_Scanf) {
CheckScanfHandler H(*this, FExpr, OrigFormatExpr, firstDataArg, numDataArgs,
Str, HasVAListArg, Args, NumArgs, format_idx,
inFunctionCall);
if (!analyze_format_string::ParseScanfString(H, Str, Str + StrLen,
getLangOpts()))
H.DoneProcessing();
} // TODO: handle other formats
}
//===--- CHECK: Standard memory functions ---------------------------------===//
/// \brief Determine whether the given type is a dynamic class type (e.g.,
/// whether it has a vtable).
static bool isDynamicClassType(QualType T) {
if (CXXRecordDecl *Record = T->getAsCXXRecordDecl())
if (CXXRecordDecl *Definition = Record->getDefinition())
if (Definition->isDynamicClass())
return true;
return false;
}
/// \brief If E is a sizeof expression, returns its argument expression,
/// otherwise returns NULL.
static const Expr *getSizeOfExprArg(const Expr* E) {
if (const UnaryExprOrTypeTraitExpr *SizeOf =
dyn_cast<UnaryExprOrTypeTraitExpr>(E))
if (SizeOf->getKind() == clang::UETT_SizeOf && !SizeOf->isArgumentType())
return SizeOf->getArgumentExpr()->IgnoreParenImpCasts();
return 0;
}
/// \brief If E is a sizeof expression, returns its argument type.
static QualType getSizeOfArgType(const Expr* E) {
if (const UnaryExprOrTypeTraitExpr *SizeOf =
dyn_cast<UnaryExprOrTypeTraitExpr>(E))
if (SizeOf->getKind() == clang::UETT_SizeOf)
return SizeOf->getTypeOfArgument();
return QualType();
}
/// \brief Check for dangerous or invalid arguments to memset().
///
/// This issues warnings on known problematic, dangerous or unspecified
/// arguments to the standard 'memset', 'memcpy', 'memmove', and 'memcmp'
/// function calls.
///
/// \param Call The call expression to diagnose.
void Sema::CheckMemaccessArguments(const CallExpr *Call,
unsigned BId,
IdentifierInfo *FnName) {
assert(BId != 0);
// It is possible to have a non-standard definition of memset. Validate
// we have enough arguments, and if not, abort further checking.
unsigned ExpectedNumArgs = (BId == Builtin::BIstrndup ? 2 : 3);
if (Call->getNumArgs() < ExpectedNumArgs)
return;
unsigned LastArg = (BId == Builtin::BImemset ||
BId == Builtin::BIstrndup ? 1 : 2);
unsigned LenArg = (BId == Builtin::BIstrndup ? 1 : 2);
const Expr *LenExpr = Call->getArg(LenArg)->IgnoreParenImpCasts();
// We have special checking when the length is a sizeof expression.
QualType SizeOfArgTy = getSizeOfArgType(LenExpr);
const Expr *SizeOfArg = getSizeOfExprArg(LenExpr);
llvm::FoldingSetNodeID SizeOfArgID;
for (unsigned ArgIdx = 0; ArgIdx != LastArg; ++ArgIdx) {
const Expr *Dest = Call->getArg(ArgIdx)->IgnoreParenImpCasts();
SourceRange ArgRange = Call->getArg(ArgIdx)->getSourceRange();
QualType DestTy = Dest->getType();
if (const PointerType *DestPtrTy = DestTy->getAs<PointerType>()) {
QualType PointeeTy = DestPtrTy->getPointeeType();
// Never warn about void type pointers. This can be used to suppress
// false positives.
if (PointeeTy->isVoidType())
continue;
// Catch "memset(p, 0, sizeof(p))" -- needs to be sizeof(*p). Do this by
// actually comparing the expressions for equality. Because computing the
// expression IDs can be expensive, we only do this if the diagnostic is
// enabled.
if (SizeOfArg &&
Diags.getDiagnosticLevel(diag::warn_sizeof_pointer_expr_memaccess,
SizeOfArg->getExprLoc())) {
// We only compute IDs for expressions if the warning is enabled, and
// cache the sizeof arg's ID.
if (SizeOfArgID == llvm::FoldingSetNodeID())
SizeOfArg->Profile(SizeOfArgID, Context, true);
llvm::FoldingSetNodeID DestID;
Dest->Profile(DestID, Context, true);
if (DestID == SizeOfArgID) {
// TODO: For strncpy() and friends, this could suggest sizeof(dst)
// over sizeof(src) as well.
unsigned ActionIdx = 0; // Default is to suggest dereferencing.
StringRef ReadableName = FnName->getName();
if (const UnaryOperator *UnaryOp = dyn_cast<UnaryOperator>(Dest))
if (UnaryOp->getOpcode() == UO_AddrOf)
ActionIdx = 1; // If its an address-of operator, just remove it.
if (Context.getTypeSize(PointeeTy) == Context.getCharWidth())
ActionIdx = 2; // If the pointee's size is sizeof(char),
// suggest an explicit length.
// If the function is defined as a builtin macro, do not show macro
// expansion.
SourceLocation SL = SizeOfArg->getExprLoc();
SourceRange DSR = Dest->getSourceRange();
SourceRange SSR = SizeOfArg->getSourceRange();
SourceManager &SM = PP.getSourceManager();
if (SM.isMacroArgExpansion(SL)) {
ReadableName = Lexer::getImmediateMacroName(SL, SM, LangOpts);
SL = SM.getSpellingLoc(SL);
DSR = SourceRange(SM.getSpellingLoc(DSR.getBegin()),
SM.getSpellingLoc(DSR.getEnd()));
SSR = SourceRange(SM.getSpellingLoc(SSR.getBegin()),
SM.getSpellingLoc(SSR.getEnd()));
}
DiagRuntimeBehavior(SL, SizeOfArg,
PDiag(diag::warn_sizeof_pointer_expr_memaccess)
<< ReadableName
<< PointeeTy
<< DestTy
<< DSR
<< SSR);
DiagRuntimeBehavior(SL, SizeOfArg,
PDiag(diag::warn_sizeof_pointer_expr_memaccess_note)
<< ActionIdx
<< SSR);
break;
}
}
// Also check for cases where the sizeof argument is the exact same
// type as the memory argument, and where it points to a user-defined
// record type.
if (SizeOfArgTy != QualType()) {
if (PointeeTy->isRecordType() &&
Context.typesAreCompatible(SizeOfArgTy, DestTy)) {
DiagRuntimeBehavior(LenExpr->getExprLoc(), Dest,
PDiag(diag::warn_sizeof_pointer_type_memaccess)
<< FnName << SizeOfArgTy << ArgIdx
<< PointeeTy << Dest->getSourceRange()
<< LenExpr->getSourceRange());
break;
}
}
// Always complain about dynamic classes.
if (isDynamicClassType(PointeeTy)) {
unsigned OperationType = 0;
// "overwritten" if we're warning about the destination for any call
// but memcmp; otherwise a verb appropriate to the call.
if (ArgIdx != 0 || BId == Builtin::BImemcmp) {
if (BId == Builtin::BImemcpy)
OperationType = 1;
else if(BId == Builtin::BImemmove)
OperationType = 2;
else if (BId == Builtin::BImemcmp)
OperationType = 3;
}
DiagRuntimeBehavior(
Dest->getExprLoc(), Dest,
PDiag(diag::warn_dyn_class_memaccess)
<< (BId == Builtin::BImemcmp ? ArgIdx + 2 : ArgIdx)
<< FnName << PointeeTy
<< OperationType
<< Call->getCallee()->getSourceRange());
} else if (PointeeTy.hasNonTrivialObjCLifetime() &&
BId != Builtin::BImemset)
DiagRuntimeBehavior(
Dest->getExprLoc(), Dest,
PDiag(diag::warn_arc_object_memaccess)
<< ArgIdx << FnName << PointeeTy
<< Call->getCallee()->getSourceRange());
else
continue;
DiagRuntimeBehavior(
Dest->getExprLoc(), Dest,
PDiag(diag::note_bad_memaccess_silence)
<< FixItHint::CreateInsertion(ArgRange.getBegin(), "(void*)"));
break;
}
}
}
// A little helper routine: ignore addition and subtraction of integer literals.
// This intentionally does not ignore all integer constant expressions because
// we don't want to remove sizeof().
static const Expr *ignoreLiteralAdditions(const Expr *Ex, ASTContext &Ctx) {
Ex = Ex->IgnoreParenCasts();
for (;;) {
const BinaryOperator * BO = dyn_cast<BinaryOperator>(Ex);
if (!BO || !BO->isAdditiveOp())
break;
const Expr *RHS = BO->getRHS()->IgnoreParenCasts();
const Expr *LHS = BO->getLHS()->IgnoreParenCasts();
if (isa<IntegerLiteral>(RHS))
Ex = LHS;
else if (isa<IntegerLiteral>(LHS))
Ex = RHS;
else
break;
}
return Ex;
}
// Warn if the user has made the 'size' argument to strlcpy or strlcat
// be the size of the source, instead of the destination.
void Sema::CheckStrlcpycatArguments(const CallExpr *Call,
IdentifierInfo *FnName) {
// Don't crash if the user has the wrong number of arguments
if (Call->getNumArgs() != 3)
return;
const Expr *SrcArg = ignoreLiteralAdditions(Call->getArg(1), Context);
const Expr *SizeArg = ignoreLiteralAdditions(Call->getArg(2), Context);
const Expr *CompareWithSrc = NULL;
// Look for 'strlcpy(dst, x, sizeof(x))'
if (const Expr *Ex = getSizeOfExprArg(SizeArg))
CompareWithSrc = Ex;
else {
// Look for 'strlcpy(dst, x, strlen(x))'
if (const CallExpr *SizeCall = dyn_cast<CallExpr>(SizeArg)) {
if (SizeCall->isBuiltinCall() == Builtin::BIstrlen
&& SizeCall->getNumArgs() == 1)
CompareWithSrc = ignoreLiteralAdditions(SizeCall->getArg(0), Context);
}
}
if (!CompareWithSrc)
return;
// Determine if the argument to sizeof/strlen is equal to the source
// argument. In principle there's all kinds of things you could do
// here, for instance creating an == expression and evaluating it with
// EvaluateAsBooleanCondition, but this uses a more direct technique:
const DeclRefExpr *SrcArgDRE = dyn_cast<DeclRefExpr>(SrcArg);
if (!SrcArgDRE)
return;
const DeclRefExpr *CompareWithSrcDRE = dyn_cast<DeclRefExpr>(CompareWithSrc);
if (!CompareWithSrcDRE ||
SrcArgDRE->getDecl() != CompareWithSrcDRE->getDecl())
return;
const Expr *OriginalSizeArg = Call->getArg(2);
Diag(CompareWithSrcDRE->getLocStart(), diag::warn_strlcpycat_wrong_size)
<< OriginalSizeArg->getSourceRange() << FnName;
// Output a FIXIT hint if the destination is an array (rather than a
// pointer to an array). This could be enhanced to handle some
// pointers if we know the actual size, like if DstArg is 'array+2'
// we could say 'sizeof(array)-2'.
const Expr *DstArg = Call->getArg(0)->IgnoreParenImpCasts();
QualType DstArgTy = DstArg->getType();
// Only handle constant-sized or VLAs, but not flexible members.
if (const ConstantArrayType *CAT = Context.getAsConstantArrayType(DstArgTy)) {
// Only issue the FIXIT for arrays of size > 1.
if (CAT->getSize().getSExtValue() <= 1)
return;
} else if (!DstArgTy->isVariableArrayType()) {
return;
}
SmallString<128> sizeString;
llvm::raw_svector_ostream OS(sizeString);
OS << "sizeof(";
DstArg->printPretty(OS, Context, 0, getPrintingPolicy());
OS << ")";
Diag(OriginalSizeArg->getLocStart(), diag::note_strlcpycat_wrong_size)
<< FixItHint::CreateReplacement(OriginalSizeArg->getSourceRange(),
OS.str());
}
/// Check if two expressions refer to the same declaration.
static bool referToTheSameDecl(const Expr *E1, const Expr *E2) {
if (const DeclRefExpr *D1 = dyn_cast_or_null<DeclRefExpr>(E1))
if (const DeclRefExpr *D2 = dyn_cast_or_null<DeclRefExpr>(E2))
return D1->getDecl() == D2->getDecl();
return false;
}
static const Expr *getStrlenExprArg(const Expr *E) {
if (const CallExpr *CE = dyn_cast<CallExpr>(E)) {
const FunctionDecl *FD = CE->getDirectCallee();
if (!FD || FD->getMemoryFunctionKind() != Builtin::BIstrlen)
return 0;
return CE->getArg(0)->IgnoreParenCasts();
}
return 0;
}
// Warn on anti-patterns as the 'size' argument to strncat.
// The correct size argument should look like following:
// strncat(dst, src, sizeof(dst) - strlen(dest) - 1);
void Sema::CheckStrncatArguments(const CallExpr *CE,
IdentifierInfo *FnName) {
// Don't crash if the user has the wrong number of arguments.
if (CE->getNumArgs() < 3)
return;
const Expr *DstArg = CE->getArg(0)->IgnoreParenCasts();
const Expr *SrcArg = CE->getArg(1)->IgnoreParenCasts();
const Expr *LenArg = CE->getArg(2)->IgnoreParenCasts();
// Identify common expressions, which are wrongly used as the size argument
// to strncat and may lead to buffer overflows.
unsigned PatternType = 0;
if (const Expr *SizeOfArg = getSizeOfExprArg(LenArg)) {
// - sizeof(dst)
if (referToTheSameDecl(SizeOfArg, DstArg))
PatternType = 1;
// - sizeof(src)
else if (referToTheSameDecl(SizeOfArg, SrcArg))
PatternType = 2;
} else if (const BinaryOperator *BE = dyn_cast<BinaryOperator>(LenArg)) {
if (BE->getOpcode() == BO_Sub) {
const Expr *L = BE->getLHS()->IgnoreParenCasts();
const Expr *R = BE->getRHS()->IgnoreParenCasts();
// - sizeof(dst) - strlen(dst)
if (referToTheSameDecl(DstArg, getSizeOfExprArg(L)) &&
referToTheSameDecl(DstArg, getStrlenExprArg(R)))
PatternType = 1;
// - sizeof(src) - (anything)
else if (referToTheSameDecl(SrcArg, getSizeOfExprArg(L)))
PatternType = 2;
}
}
if (PatternType == 0)
return;
// Generate the diagnostic.
SourceLocation SL = LenArg->getLocStart();
SourceRange SR = LenArg->getSourceRange();
SourceManager &SM = PP.getSourceManager();
// If the function is defined as a builtin macro, do not show macro expansion.
if (SM.isMacroArgExpansion(SL)) {
SL = SM.getSpellingLoc(SL);
SR = SourceRange(SM.getSpellingLoc(SR.getBegin()),
SM.getSpellingLoc(SR.getEnd()));
}
if (PatternType == 1)
Diag(SL, diag::warn_strncat_large_size) << SR;
else
Diag(SL, diag::warn_strncat_src_size) << SR;
// Output a FIXIT hint if the destination is an array (rather than a
// pointer to an array). This could be enhanced to handle some
// pointers if we know the actual size, like if DstArg is 'array+2'
// we could say 'sizeof(array)-2'.
QualType DstArgTy = DstArg->getType();
// Only handle constant-sized or VLAs, but not flexible members.
if (const ConstantArrayType *CAT = Context.getAsConstantArrayType(DstArgTy)) {
// Only issue the FIXIT for arrays of size > 1.
if (CAT->getSize().getSExtValue() <= 1)
return;
} else if (!DstArgTy->isVariableArrayType()) {
return;
}
SmallString<128> sizeString;
llvm::raw_svector_ostream OS(sizeString);
OS << "sizeof(";
DstArg->printPretty(OS, Context, 0, getPrintingPolicy());
OS << ") - ";
OS << "strlen(";
DstArg->printPretty(OS, Context, 0, getPrintingPolicy());
OS << ") - 1";
Diag(SL, diag::note_strncat_wrong_size)
<< FixItHint::CreateReplacement(SR, OS.str());
}
//===--- CHECK: Return Address of Stack Variable --------------------------===//
static Expr *EvalVal(Expr *E, SmallVectorImpl<DeclRefExpr *> &refVars,
Decl *ParentDecl);
static Expr *EvalAddr(Expr* E, SmallVectorImpl<DeclRefExpr *> &refVars,
Decl *ParentDecl);
/// CheckReturnStackAddr - Check if a return statement returns the address
/// of a stack variable.
void
Sema::CheckReturnStackAddr(Expr *RetValExp, QualType lhsType,
SourceLocation ReturnLoc) {
Expr *stackE = 0;
SmallVector<DeclRefExpr *, 8> refVars;
// Perform checking for returned stack addresses, local blocks,
// label addresses or references to temporaries.
if (lhsType->isPointerType() ||
(!getLangOpts().ObjCAutoRefCount && lhsType->isBlockPointerType())) {
stackE = EvalAddr(RetValExp, refVars, /*ParentDecl=*/0);
} else if (lhsType->isReferenceType()) {
stackE = EvalVal(RetValExp, refVars, /*ParentDecl=*/0);
}
if (stackE == 0)
return; // Nothing suspicious was found.
SourceLocation diagLoc;
SourceRange diagRange;
if (refVars.empty()) {
diagLoc = stackE->getLocStart();
diagRange = stackE->getSourceRange();
} else {
// We followed through a reference variable. 'stackE' contains the
// problematic expression but we will warn at the return statement pointing
// at the reference variable. We will later display the "trail" of
// reference variables using notes.
diagLoc = refVars[0]->getLocStart();
diagRange = refVars[0]->getSourceRange();
}
if (DeclRefExpr *DR = dyn_cast<DeclRefExpr>(stackE)) { //address of local var.
Diag(diagLoc, lhsType->isReferenceType() ? diag::warn_ret_stack_ref
: diag::warn_ret_stack_addr)
<< DR->getDecl()->getDeclName() << diagRange;
} else if (isa<BlockExpr>(stackE)) { // local block.
Diag(diagLoc, diag::err_ret_local_block) << diagRange;
} else if (isa<AddrLabelExpr>(stackE)) { // address of label.
Diag(diagLoc, diag::warn_ret_addr_label) << diagRange;
} else { // local temporary.
Diag(diagLoc, lhsType->isReferenceType() ? diag::warn_ret_local_temp_ref
: diag::warn_ret_local_temp_addr)
<< diagRange;
}
// Display the "trail" of reference variables that we followed until we
// found the problematic expression using notes.
for (unsigned i = 0, e = refVars.size(); i != e; ++i) {
VarDecl *VD = cast<VarDecl>(refVars[i]->getDecl());
// If this var binds to another reference var, show the range of the next
// var, otherwise the var binds to the problematic expression, in which case
// show the range of the expression.
SourceRange range = (i < e-1) ? refVars[i+1]->getSourceRange()
: stackE->getSourceRange();
Diag(VD->getLocation(), diag::note_ref_var_local_bind)
<< VD->getDeclName() << range;
}
}
/// EvalAddr - EvalAddr and EvalVal are mutually recursive functions that
/// check if the expression in a return statement evaluates to an address
/// to a location on the stack, a local block, an address of a label, or a
/// reference to local temporary. The recursion is used to traverse the
/// AST of the return expression, with recursion backtracking when we
/// encounter a subexpression that (1) clearly does not lead to one of the
/// above problematic expressions (2) is something we cannot determine leads to
/// a problematic expression based on such local checking.
///
/// Both EvalAddr and EvalVal follow through reference variables to evaluate
/// the expression that they point to. Such variables are added to the
/// 'refVars' vector so that we know what the reference variable "trail" was.
///
/// EvalAddr processes expressions that are pointers that are used as
/// references (and not L-values). EvalVal handles all other values.
/// At the base case of the recursion is a check for the above problematic
/// expressions.
///
/// This implementation handles:
///
/// * pointer-to-pointer casts
/// * implicit conversions from array references to pointers
/// * taking the address of fields
/// * arbitrary interplay between "&" and "*" operators
/// * pointer arithmetic from an address of a stack variable
/// * taking the address of an array element where the array is on the stack
static Expr *EvalAddr(Expr *E, SmallVectorImpl<DeclRefExpr *> &refVars,
Decl *ParentDecl) {
if (E->isTypeDependent())
return NULL;
// We should only be called for evaluating pointer expressions.
assert((E->getType()->isAnyPointerType() ||
E->getType()->isBlockPointerType() ||
E->getType()->isObjCQualifiedIdType()) &&
"EvalAddr only works on pointers");
E = E->IgnoreParens();
// Our "symbolic interpreter" is just a dispatch off the currently
// viewed AST node. We then recursively traverse the AST by calling
// EvalAddr and EvalVal appropriately.
switch (E->getStmtClass()) {
case Stmt::DeclRefExprClass: {
DeclRefExpr *DR = cast<DeclRefExpr>(E);
if (VarDecl *V = dyn_cast<VarDecl>(DR->getDecl()))
// If this is a reference variable, follow through to the expression that
// it points to.
if (V->hasLocalStorage() &&
V->getType()->isReferenceType() && V->hasInit()) {
// Add the reference variable to the "trail".
refVars.push_back(DR);
return EvalAddr(V->getInit(), refVars, ParentDecl);
}
return NULL;
}
case Stmt::UnaryOperatorClass: {
// The only unary operator that make sense to handle here
// is AddrOf. All others don't make sense as pointers.
UnaryOperator *U = cast<UnaryOperator>(E);
if (U->getOpcode() == UO_AddrOf)
return EvalVal(U->getSubExpr(), refVars, ParentDecl);
else
return NULL;
}
case Stmt::BinaryOperatorClass: {
// Handle pointer arithmetic. All other binary operators are not valid
// in this context.
BinaryOperator *B = cast<BinaryOperator>(E);
BinaryOperatorKind op = B->getOpcode();
if (op != BO_Add && op != BO_Sub)
return NULL;
Expr *Base = B->getLHS();
// Determine which argument is the real pointer base. It could be
// the RHS argument instead of the LHS.
if (!Base->getType()->isPointerType()) Base = B->getRHS();
assert (Base->getType()->isPointerType());
return EvalAddr(Base, refVars, ParentDecl);
}
// For conditional operators we need to see if either the LHS or RHS are
// valid DeclRefExpr*s. If one of them is valid, we return it.
case Stmt::ConditionalOperatorClass: {
ConditionalOperator *C = cast<ConditionalOperator>(E);
// Handle the GNU extension for missing LHS.
if (Expr *lhsExpr = C->getLHS()) {
// In C++, we can have a throw-expression, which has 'void' type.
if (!lhsExpr->getType()->isVoidType())
if (Expr* LHS = EvalAddr(lhsExpr, refVars, ParentDecl))
return LHS;
}
// In C++, we can have a throw-expression, which has 'void' type.
if (C->getRHS()->getType()->isVoidType())
return NULL;
return EvalAddr(C->getRHS(), refVars, ParentDecl);
}
case Stmt::BlockExprClass:
if (cast<BlockExpr>(E)->getBlockDecl()->hasCaptures())
return E; // local block.
return NULL;
case Stmt::AddrLabelExprClass:
return E; // address of label.
case Stmt::ExprWithCleanupsClass:
return EvalAddr(cast<ExprWithCleanups>(E)->getSubExpr(), refVars,
ParentDecl);
// For casts, we need to handle conversions from arrays to
// pointer values, and pointer-to-pointer conversions.
case Stmt::ImplicitCastExprClass:
case Stmt::CStyleCastExprClass:
case Stmt::CXXFunctionalCastExprClass:
case Stmt::ObjCBridgedCastExprClass:
case Stmt::CXXStaticCastExprClass:
case Stmt::CXXDynamicCastExprClass:
case Stmt::CXXConstCastExprClass:
case Stmt::CXXReinterpretCastExprClass: {
Expr* SubExpr = cast<CastExpr>(E)->getSubExpr();
switch (cast<CastExpr>(E)->getCastKind()) {
case CK_BitCast:
case CK_LValueToRValue:
case CK_NoOp:
case CK_BaseToDerived:
case CK_DerivedToBase:
case CK_UncheckedDerivedToBase:
case CK_Dynamic:
case CK_CPointerToObjCPointerCast:
case CK_BlockPointerToObjCPointerCast:
case CK_AnyPointerToBlockPointerCast:
return EvalAddr(SubExpr, refVars, ParentDecl);
case CK_ArrayToPointerDecay:
return EvalVal(SubExpr, refVars, ParentDecl);
default:
return 0;
}
}
case Stmt::MaterializeTemporaryExprClass:
if (Expr *Result = EvalAddr(
cast<MaterializeTemporaryExpr>(E)->GetTemporaryExpr(),
refVars, ParentDecl))
return Result;
return E;
// Everything else: we simply don't reason about them.
default:
return NULL;
}
}
/// EvalVal - This function is complements EvalAddr in the mutual recursion.
/// See the comments for EvalAddr for more details.
static Expr *EvalVal(Expr *E, SmallVectorImpl<DeclRefExpr *> &refVars,
Decl *ParentDecl) {
do {
// We should only be called for evaluating non-pointer expressions, or
// expressions with a pointer type that are not used as references but instead
// are l-values (e.g., DeclRefExpr with a pointer type).
// Our "symbolic interpreter" is just a dispatch off the currently
// viewed AST node. We then recursively traverse the AST by calling
// EvalAddr and EvalVal appropriately.
E = E->IgnoreParens();
switch (E->getStmtClass()) {
case Stmt::ImplicitCastExprClass: {
ImplicitCastExpr *IE = cast<ImplicitCastExpr>(E);
if (IE->getValueKind() == VK_LValue) {
E = IE->getSubExpr();
continue;
}
return NULL;
}
case Stmt::ExprWithCleanupsClass:
return EvalVal(cast<ExprWithCleanups>(E)->getSubExpr(), refVars,ParentDecl);
case Stmt::DeclRefExprClass: {
// When we hit a DeclRefExpr we are looking at code that refers to a
// variable's name. If it's not a reference variable we check if it has
// local storage within the function, and if so, return the expression.
DeclRefExpr *DR = cast<DeclRefExpr>(E);
if (VarDecl *V = dyn_cast<VarDecl>(DR->getDecl())) {
// Check if it refers to itself, e.g. "int& i = i;".
if (V == ParentDecl)
return DR;
if (V->hasLocalStorage()) {
if (!V->getType()->isReferenceType())
return DR;
// Reference variable, follow through to the expression that
// it points to.
if (V->hasInit()) {
// Add the reference variable to the "trail".
refVars.push_back(DR);
return EvalVal(V->getInit(), refVars, V);
}
}
}
return NULL;
}
case Stmt::UnaryOperatorClass: {
// The only unary operator that make sense to handle here
// is Deref. All others don't resolve to a "name." This includes
// handling all sorts of rvalues passed to a unary operator.
UnaryOperator *U = cast<UnaryOperator>(E);
if (U->getOpcode() == UO_Deref)
return EvalAddr(U->getSubExpr(), refVars, ParentDecl);
return NULL;
}
case Stmt::ArraySubscriptExprClass: {
// Array subscripts are potential references to data on the stack. We
// retrieve the DeclRefExpr* for the array variable if it indeed
// has local storage.
return EvalAddr(cast<ArraySubscriptExpr>(E)->getBase(), refVars,ParentDecl);
}
case Stmt::ConditionalOperatorClass: {
// For conditional operators we need to see if either the LHS or RHS are
// non-NULL Expr's. If one is non-NULL, we return it.
ConditionalOperator *C = cast<ConditionalOperator>(E);
// Handle the GNU extension for missing LHS.
if (Expr *lhsExpr = C->getLHS())
if (Expr *LHS = EvalVal(lhsExpr, refVars, ParentDecl))
return LHS;
return EvalVal(C->getRHS(), refVars, ParentDecl);
}
// Accesses to members are potential references to data on the stack.
case Stmt::MemberExprClass: {
MemberExpr *M = cast<MemberExpr>(E);
// Check for indirect access. We only want direct field accesses.
if (M->isArrow())
return NULL;
// Check whether the member type is itself a reference, in which case
// we're not going to refer to the member, but to what the member refers to.
if (M->getMemberDecl()->getType()->isReferenceType())
return NULL;
return EvalVal(M->getBase(), refVars, ParentDecl);
}
case Stmt::MaterializeTemporaryExprClass:
if (Expr *Result = EvalVal(
cast<MaterializeTemporaryExpr>(E)->GetTemporaryExpr(),
refVars, ParentDecl))
return Result;
return E;
default:
// Check that we don't return or take the address of a reference to a
// temporary. This is only useful in C++.
if (!E->isTypeDependent() && E->isRValue())
return E;
// Everything else: we simply don't reason about them.
return NULL;
}
} while (true);
}
//===--- CHECK: Floating-Point comparisons (-Wfloat-equal) ---------------===//
/// Check for comparisons of floating point operands using != and ==.
/// Issue a warning if these are no self-comparisons, as they are not likely
/// to do what the programmer intended.
void Sema::CheckFloatComparison(SourceLocation Loc, Expr* LHS, Expr *RHS) {
bool EmitWarning = true;
Expr* LeftExprSansParen = LHS->IgnoreParenImpCasts();
Expr* RightExprSansParen = RHS->IgnoreParenImpCasts();
// Special case: check for x == x (which is OK).
// Do not emit warnings for such cases.
if (DeclRefExpr* DRL = dyn_cast<DeclRefExpr>(LeftExprSansParen))
if (DeclRefExpr* DRR = dyn_cast<DeclRefExpr>(RightExprSansParen))
if (DRL->getDecl() == DRR->getDecl())
EmitWarning = false;
// Special case: check for comparisons against literals that can be exactly
// represented by APFloat. In such cases, do not emit a warning. This
// is a heuristic: often comparison against such literals are used to
// detect if a value in a variable has not changed. This clearly can
// lead to false negatives.
if (EmitWarning) {
if (FloatingLiteral* FLL = dyn_cast<FloatingLiteral>(LeftExprSansParen)) {
if (FLL->isExact())
EmitWarning = false;
} else
if (FloatingLiteral* FLR = dyn_cast<FloatingLiteral>(RightExprSansParen)){
if (FLR->isExact())
EmitWarning = false;
}
}
// Check for comparisons with builtin types.
if (EmitWarning)
if (CallExpr* CL = dyn_cast<CallExpr>(LeftExprSansParen))
if (CL->isBuiltinCall())
EmitWarning = false;
if (EmitWarning)
if (CallExpr* CR = dyn_cast<CallExpr>(RightExprSansParen))
if (CR->isBuiltinCall())
EmitWarning = false;
// Emit the diagnostic.
if (EmitWarning)
Diag(Loc, diag::warn_floatingpoint_eq)
<< LHS->getSourceRange() << RHS->getSourceRange();
}
//===--- CHECK: Integer mixed-sign comparisons (-Wsign-compare) --------===//
//===--- CHECK: Lossy implicit conversions (-Wconversion) --------------===//
namespace {
/// Structure recording the 'active' range of an integer-valued
/// expression.
struct IntRange {
/// The number of bits active in the int.
unsigned Width;
/// True if the int is known not to have negative values.
bool NonNegative;
IntRange(unsigned Width, bool NonNegative)
: Width(Width), NonNegative(NonNegative)
{}
/// Returns the range of the bool type.
static IntRange forBoolType() {
return IntRange(1, true);
}
/// Returns the range of an opaque value of the given integral type.
static IntRange forValueOfType(ASTContext &C, QualType T) {
return forValueOfCanonicalType(C,
T->getCanonicalTypeInternal().getTypePtr());
}
/// Returns the range of an opaque value of a canonical integral type.
static IntRange forValueOfCanonicalType(ASTContext &C, const Type *T) {
assert(T->isCanonicalUnqualified());
if (const VectorType *VT = dyn_cast<VectorType>(T))
T = VT->getElementType().getTypePtr();
if (const ComplexType *CT = dyn_cast<ComplexType>(T))
T = CT->getElementType().getTypePtr();
// For enum types, use the known bit width of the enumerators.
if (const EnumType *ET = dyn_cast<EnumType>(T)) {
EnumDecl *Enum = ET->getDecl();
if (!Enum->isCompleteDefinition())
return IntRange(C.getIntWidth(QualType(T, 0)), false);
unsigned NumPositive = Enum->getNumPositiveBits();
unsigned NumNegative = Enum->getNumNegativeBits();
return IntRange(std::max(NumPositive, NumNegative), NumNegative == 0);
}
const BuiltinType *BT = cast<BuiltinType>(T);
assert(BT->isInteger());
return IntRange(C.getIntWidth(QualType(T, 0)), BT->isUnsignedInteger());
}
/// Returns the "target" range of a canonical integral type, i.e.
/// the range of values expressible in the type.
///
/// This matches forValueOfCanonicalType except that enums have the
/// full range of their type, not the range of their enumerators.
static IntRange forTargetOfCanonicalType(ASTContext &C, const Type *T) {
assert(T->isCanonicalUnqualified());
if (const VectorType *VT = dyn_cast<VectorType>(T))
T = VT->getElementType().getTypePtr();
if (const ComplexType *CT = dyn_cast<ComplexType>(T))
T = CT->getElementType().getTypePtr();
if (const EnumType *ET = dyn_cast<EnumType>(T))
T = C.getCanonicalType(ET->getDecl()->getIntegerType()).getTypePtr();
const BuiltinType *BT = cast<BuiltinType>(T);
assert(BT->isInteger());
return IntRange(C.getIntWidth(QualType(T, 0)), BT->isUnsignedInteger());
}
/// Returns the supremum of two ranges: i.e. their conservative merge.
static IntRange join(IntRange L, IntRange R) {
return IntRange(std::max(L.Width, R.Width),
L.NonNegative && R.NonNegative);
}
/// Returns the infinum of two ranges: i.e. their aggressive merge.
static IntRange meet(IntRange L, IntRange R) {
return IntRange(std::min(L.Width, R.Width),
L.NonNegative || R.NonNegative);
}
};
static IntRange GetValueRange(ASTContext &C, llvm::APSInt &value,
unsigned MaxWidth) {
if (value.isSigned() && value.isNegative())
return IntRange(value.getMinSignedBits(), false);
if (value.getBitWidth() > MaxWidth)
value = value.trunc(MaxWidth);
// isNonNegative() just checks the sign bit without considering
// signedness.
return IntRange(value.getActiveBits(), true);
}
static IntRange GetValueRange(ASTContext &C, APValue &result, QualType Ty,
unsigned MaxWidth) {
if (result.isInt())
return GetValueRange(C, result.getInt(), MaxWidth);
if (result.isVector()) {
IntRange R = GetValueRange(C, result.getVectorElt(0), Ty, MaxWidth);
for (unsigned i = 1, e = result.getVectorLength(); i != e; ++i) {
IntRange El = GetValueRange(C, result.getVectorElt(i), Ty, MaxWidth);
R = IntRange::join(R, El);
}
return R;
}
if (result.isComplexInt()) {
IntRange R = GetValueRange(C, result.getComplexIntReal(), MaxWidth);
IntRange I = GetValueRange(C, result.getComplexIntImag(), MaxWidth);
return IntRange::join(R, I);
}
// This can happen with lossless casts to intptr_t of "based" lvalues.
// Assume it might use arbitrary bits.
// FIXME: The only reason we need to pass the type in here is to get
// the sign right on this one case. It would be nice if APValue
// preserved this.
assert(result.isLValue() || result.isAddrLabelDiff());
return IntRange(MaxWidth, Ty->isUnsignedIntegerOrEnumerationType());
}
/// Pseudo-evaluate the given integer expression, estimating the
/// range of values it might take.
///
/// \param MaxWidth - the width to which the value will be truncated
static IntRange GetExprRange(ASTContext &C, Expr *E, unsigned MaxWidth) {
E = E->IgnoreParens();
// Try a full evaluation first.
Expr::EvalResult result;
if (E->EvaluateAsRValue(result, C))
return GetValueRange(C, result.Val, E->getType(), MaxWidth);
// I think we only want to look through implicit casts here; if the
// user has an explicit widening cast, we should treat the value as
// being of the new, wider type.
if (ImplicitCastExpr *CE = dyn_cast<ImplicitCastExpr>(E)) {
if (CE->getCastKind() == CK_NoOp || CE->getCastKind() == CK_LValueToRValue)
return GetExprRange(C, CE->getSubExpr(), MaxWidth);
IntRange OutputTypeRange = IntRange::forValueOfType(C, CE->getType());
bool isIntegerCast = (CE->getCastKind() == CK_IntegralCast);
// Assume that non-integer casts can span the full range of the type.
if (!isIntegerCast)
return OutputTypeRange;
IntRange SubRange
= GetExprRange(C, CE->getSubExpr(),
std::min(MaxWidth, OutputTypeRange.Width));
// Bail out if the subexpr's range is as wide as the cast type.
if (SubRange.Width >= OutputTypeRange.Width)
return OutputTypeRange;
// Otherwise, we take the smaller width, and we're non-negative if
// either the output type or the subexpr is.
return IntRange(SubRange.Width,
SubRange.NonNegative || OutputTypeRange.NonNegative);
}
if (ConditionalOperator *CO = dyn_cast<ConditionalOperator>(E)) {
// If we can fold the condition, just take that operand.
bool CondResult;
if (CO->getCond()->EvaluateAsBooleanCondition(CondResult, C))
return GetExprRange(C, CondResult ? CO->getTrueExpr()
: CO->getFalseExpr(),
MaxWidth);
// Otherwise, conservatively merge.
IntRange L = GetExprRange(C, CO->getTrueExpr(), MaxWidth);
IntRange R = GetExprRange(C, CO->getFalseExpr(), MaxWidth);
return IntRange::join(L, R);
}
if (BinaryOperator *BO = dyn_cast<BinaryOperator>(E)) {
switch (BO->getOpcode()) {
// Boolean-valued operations are single-bit and positive.
case BO_LAnd:
case BO_LOr:
case BO_LT:
case BO_GT:
case BO_LE:
case BO_GE:
case BO_EQ:
case BO_NE:
return IntRange::forBoolType();
// The type of the assignments is the type of the LHS, so the RHS
// is not necessarily the same type.
case BO_MulAssign:
case BO_DivAssign:
case BO_RemAssign:
case BO_AddAssign:
case BO_SubAssign:
case BO_XorAssign:
case BO_OrAssign:
// TODO: bitfields?
return IntRange::forValueOfType(C, E->getType());
// Simple assignments just pass through the RHS, which will have
// been coerced to the LHS type.
case BO_Assign:
// TODO: bitfields?
return GetExprRange(C, BO->getRHS(), MaxWidth);
// Operations with opaque sources are black-listed.
case BO_PtrMemD:
case BO_PtrMemI:
return IntRange::forValueOfType(C, E->getType());
// Bitwise-and uses the *infinum* of the two source ranges.
case BO_And:
case BO_AndAssign:
return IntRange::meet(GetExprRange(C, BO->getLHS(), MaxWidth),
GetExprRange(C, BO->getRHS(), MaxWidth));
// Left shift gets black-listed based on a judgement call.
case BO_Shl:
// ...except that we want to treat '1 << (blah)' as logically
// positive. It's an important idiom.
if (IntegerLiteral *I
= dyn_cast<IntegerLiteral>(BO->getLHS()->IgnoreParenCasts())) {
if (I->getValue() == 1) {
IntRange R = IntRange::forValueOfType(C, E->getType());
return IntRange(R.Width, /*NonNegative*/ true);
}
}
// fallthrough
case BO_ShlAssign:
return IntRange::forValueOfType(C, E->getType());
// Right shift by a constant can narrow its left argument.
case BO_Shr:
case BO_ShrAssign: {
IntRange L = GetExprRange(C, BO->getLHS(), MaxWidth);
// If the shift amount is a positive constant, drop the width by
// that much.
llvm::APSInt shift;
if (BO->getRHS()->isIntegerConstantExpr(shift, C) &&
shift.isNonNegative()) {
unsigned zext = shift.getZExtValue();
if (zext >= L.Width)
L.Width = (L.NonNegative ? 0 : 1);
else
L.Width -= zext;
}
return L;
}
// Comma acts as its right operand.
case BO_Comma:
return GetExprRange(C, BO->getRHS(), MaxWidth);
// Black-list pointer subtractions.
case BO_Sub:
if (BO->getLHS()->getType()->isPointerType())
return IntRange::forValueOfType(C, E->getType());
break;
// The width of a division result is mostly determined by the size
// of the LHS.
case BO_Div: {
// Don't 'pre-truncate' the operands.
unsigned opWidth = C.getIntWidth(E->getType());
IntRange L = GetExprRange(C, BO->getLHS(), opWidth);
// If the divisor is constant, use that.
llvm::APSInt divisor;
if (BO->getRHS()->isIntegerConstantExpr(divisor, C)) {
unsigned log2 = divisor.logBase2(); // floor(log_2(divisor))
if (log2 >= L.Width)
L.Width = (L.NonNegative ? 0 : 1);
else
L.Width = std::min(L.Width - log2, MaxWidth);
return L;
}
// Otherwise, just use the LHS's width.
IntRange R = GetExprRange(C, BO->getRHS(), opWidth);
return IntRange(L.Width, L.NonNegative && R.NonNegative);
}
// The result of a remainder can't be larger than the result of
// either side.
case BO_Rem: {
// Don't 'pre-truncate' the operands.
unsigned opWidth = C.getIntWidth(E->getType());
IntRange L = GetExprRange(C, BO->getLHS(), opWidth);
IntRange R = GetExprRange(C, BO->getRHS(), opWidth);
IntRange meet = IntRange::meet(L, R);
meet.Width = std::min(meet.Width, MaxWidth);
return meet;
}
// The default behavior is okay for these.
case BO_Mul:
case BO_Add:
case BO_Xor:
case BO_Or:
break;
}
// The default case is to treat the operation as if it were closed
// on the narrowest type that encompasses both operands.
IntRange L = GetExprRange(C, BO->getLHS(), MaxWidth);
IntRange R = GetExprRange(C, BO->getRHS(), MaxWidth);
return IntRange::join(L, R);
}
if (UnaryOperator *UO = dyn_cast<UnaryOperator>(E)) {
switch (UO->getOpcode()) {
// Boolean-valued operations are white-listed.
case UO_LNot:
return IntRange::forBoolType();
// Operations with opaque sources are black-listed.
case UO_Deref:
case UO_AddrOf: // should be impossible
return IntRange::forValueOfType(C, E->getType());
default:
return GetExprRange(C, UO->getSubExpr(), MaxWidth);
}
}
if (dyn_cast<OffsetOfExpr>(E)) {
IntRange::forValueOfType(C, E->getType());
}
if (FieldDecl *BitField = E->getBitField())
return IntRange(BitField->getBitWidthValue(C),
BitField->getType()->isUnsignedIntegerOrEnumerationType());
return IntRange::forValueOfType(C, E->getType());
}
static IntRange GetExprRange(ASTContext &C, Expr *E) {
return GetExprRange(C, E, C.getIntWidth(E->getType()));
}
/// Checks whether the given value, which currently has the given
/// source semantics, has the same value when coerced through the
/// target semantics.
static bool IsSameFloatAfterCast(const llvm::APFloat &value,
const llvm::fltSemantics &Src,
const llvm::fltSemantics &Tgt) {
llvm::APFloat truncated = value;
bool ignored;
truncated.convert(Src, llvm::APFloat::rmNearestTiesToEven, &ignored);
truncated.convert(Tgt, llvm::APFloat::rmNearestTiesToEven, &ignored);
return truncated.bitwiseIsEqual(value);
}
/// Checks whether the given value, which currently has the given
/// source semantics, has the same value when coerced through the
/// target semantics.
///
/// The value might be a vector of floats (or a complex number).
static bool IsSameFloatAfterCast(const APValue &value,
const llvm::fltSemantics &Src,
const llvm::fltSemantics &Tgt) {
if (value.isFloat())
return IsSameFloatAfterCast(value.getFloat(), Src, Tgt);
if (value.isVector()) {
for (unsigned i = 0, e = value.getVectorLength(); i != e; ++i)
if (!IsSameFloatAfterCast(value.getVectorElt(i), Src, Tgt))
return false;
return true;
}
assert(value.isComplexFloat());
return (IsSameFloatAfterCast(value.getComplexFloatReal(), Src, Tgt) &&
IsSameFloatAfterCast(value.getComplexFloatImag(), Src, Tgt));
}
static void AnalyzeImplicitConversions(Sema &S, Expr *E, SourceLocation CC);
static bool IsZero(Sema &S, Expr *E) {
// Suppress cases where we are comparing against an enum constant.
if (const DeclRefExpr *DR =
dyn_cast<DeclRefExpr>(E->IgnoreParenImpCasts()))
if (isa<EnumConstantDecl>(DR->getDecl()))
return false;
// Suppress cases where the '0' value is expanded from a macro.
if (E->getLocStart().isMacroID())
return false;
llvm::APSInt Value;
return E->isIntegerConstantExpr(Value, S.Context) && Value == 0;
}
static bool HasEnumType(Expr *E) {
// Strip off implicit integral promotions.
while (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(E)) {
if (ICE->getCastKind() != CK_IntegralCast &&
ICE->getCastKind() != CK_NoOp)
break;
E = ICE->getSubExpr();
}
return E->getType()->isEnumeralType();
}
static void CheckTrivialUnsignedComparison(Sema &S, BinaryOperator *E) {
BinaryOperatorKind op = E->getOpcode();
if (E->isValueDependent())
return;
if (op == BO_LT && IsZero(S, E->getRHS())) {
S.Diag(E->getOperatorLoc(), diag::warn_lunsigned_always_true_comparison)
<< "< 0" << "false" << HasEnumType(E->getLHS())
<< E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange();
} else if (op == BO_GE && IsZero(S, E->getRHS())) {
S.Diag(E->getOperatorLoc(), diag::warn_lunsigned_always_true_comparison)
<< ">= 0" << "true" << HasEnumType(E->getLHS())
<< E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange();
} else if (op == BO_GT && IsZero(S, E->getLHS())) {
S.Diag(E->getOperatorLoc(), diag::warn_runsigned_always_true_comparison)
<< "0 >" << "false" << HasEnumType(E->getRHS())
<< E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange();
} else if (op == BO_LE && IsZero(S, E->getLHS())) {
S.Diag(E->getOperatorLoc(), diag::warn_runsigned_always_true_comparison)
<< "0 <=" << "true" << HasEnumType(E->getRHS())
<< E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange();
}
}
/// Analyze the operands of the given comparison. Implements the
/// fallback case from AnalyzeComparison.
static void AnalyzeImpConvsInComparison(Sema &S, BinaryOperator *E) {
AnalyzeImplicitConversions(S, E->getLHS(), E->getOperatorLoc());
AnalyzeImplicitConversions(S, E->getRHS(), E->getOperatorLoc());
}
/// \brief Implements -Wsign-compare.
///
/// \param E the binary operator to check for warnings
static void AnalyzeComparison(Sema &S, BinaryOperator *E) {
// The type the comparison is being performed in.
QualType T = E->getLHS()->getType();
assert(S.Context.hasSameUnqualifiedType(T, E->getRHS()->getType())
&& "comparison with mismatched types");
// We don't do anything special if this isn't an unsigned integral
// comparison: we're only interested in integral comparisons, and
// signed comparisons only happen in cases we don't care to warn about.
//
// We also don't care about value-dependent expressions or expressions
// whose result is a constant.
if (!T->hasUnsignedIntegerRepresentation()
|| E->isValueDependent() || E->isIntegerConstantExpr(S.Context))
return AnalyzeImpConvsInComparison(S, E);
Expr *LHS = E->getLHS()->IgnoreParenImpCasts();
Expr *RHS = E->getRHS()->IgnoreParenImpCasts();
// Check to see if one of the (unmodified) operands is of different
// signedness.
Expr *signedOperand, *unsignedOperand;
if (LHS->getType()->hasSignedIntegerRepresentation()) {
assert(!RHS->getType()->hasSignedIntegerRepresentation() &&
"unsigned comparison between two signed integer expressions?");
signedOperand = LHS;
unsignedOperand = RHS;
} else if (RHS->getType()->hasSignedIntegerRepresentation()) {
signedOperand = RHS;
unsignedOperand = LHS;
} else {
CheckTrivialUnsignedComparison(S, E);
return AnalyzeImpConvsInComparison(S, E);
}
// Otherwise, calculate the effective range of the signed operand.
IntRange signedRange = GetExprRange(S.Context, signedOperand);
// Go ahead and analyze implicit conversions in the operands. Note
// that we skip the implicit conversions on both sides.
AnalyzeImplicitConversions(S, LHS, E->getOperatorLoc());
AnalyzeImplicitConversions(S, RHS, E->getOperatorLoc());
// If the signed range is non-negative, -Wsign-compare won't fire,
// but we should still check for comparisons which are always true
// or false.
if (signedRange.NonNegative)
return CheckTrivialUnsignedComparison(S, E);
// For (in)equality comparisons, if the unsigned operand is a
// constant which cannot collide with a overflowed signed operand,
// then reinterpreting the signed operand as unsigned will not
// change the result of the comparison.
if (E->isEqualityOp()) {
unsigned comparisonWidth = S.Context.getIntWidth(T);
IntRange unsignedRange = GetExprRange(S.Context, unsignedOperand);
// We should never be unable to prove that the unsigned operand is
// non-negative.
assert(unsignedRange.NonNegative && "unsigned range includes negative?");
if (unsignedRange.Width < comparisonWidth)
return;
}
S.DiagRuntimeBehavior(E->getOperatorLoc(), E,
S.PDiag(diag::warn_mixed_sign_comparison)
<< LHS->getType() << RHS->getType()
<< LHS->getSourceRange() << RHS->getSourceRange());
}
/// Analyzes an attempt to assign the given value to a bitfield.
///
/// Returns true if there was something fishy about the attempt.
static bool AnalyzeBitFieldAssignment(Sema &S, FieldDecl *Bitfield, Expr *Init,
SourceLocation InitLoc) {
assert(Bitfield->isBitField());
if (Bitfield->isInvalidDecl())
return false;
// White-list bool bitfields.
if (Bitfield->getType()->isBooleanType())
return false;
// Ignore value- or type-dependent expressions.
if (Bitfield->getBitWidth()->isValueDependent() ||
Bitfield->getBitWidth()->isTypeDependent() ||
Init->isValueDependent() ||
Init->isTypeDependent())
return false;
Expr *OriginalInit = Init->IgnoreParenImpCasts();
llvm::APSInt Value;
if (!OriginalInit->EvaluateAsInt(Value, S.Context, Expr::SE_AllowSideEffects))
return false;
unsigned OriginalWidth = Value.getBitWidth();
unsigned FieldWidth = Bitfield->getBitWidthValue(S.Context);
if (OriginalWidth <= FieldWidth)
return false;
// Compute the value which the bitfield will contain.
llvm::APSInt TruncatedValue = Value.trunc(FieldWidth);
TruncatedValue.setIsSigned(Bitfield->getType()->isSignedIntegerType());
// Check whether the stored value is equal to the original value.
TruncatedValue = TruncatedValue.extend(OriginalWidth);
if (Value == TruncatedValue)
return false;
// Special-case bitfields of width 1: booleans are naturally 0/1, and
// therefore don't strictly fit into a signed bitfield of width 1.
if (FieldWidth == 1 && Value == 1)
return false;
std::string PrettyValue = Value.toString(10);
std::string PrettyTrunc = TruncatedValue.toString(10);
S.Diag(InitLoc, diag::warn_impcast_bitfield_precision_constant)
<< PrettyValue << PrettyTrunc << OriginalInit->getType()
<< Init->getSourceRange();
return true;
}
/// Analyze the given simple or compound assignment for warning-worthy
/// operations.
static void AnalyzeAssignment(Sema &S, BinaryOperator *E) {
// Just recurse on the LHS.
AnalyzeImplicitConversions(S, E->getLHS(), E->getOperatorLoc());
// We want to recurse on the RHS as normal unless we're assigning to
// a bitfield.
if (FieldDecl *Bitfield = E->getLHS()->getBitField()) {
if (AnalyzeBitFieldAssignment(S, Bitfield, E->getRHS(),
E->getOperatorLoc())) {
// Recurse, ignoring any implicit conversions on the RHS.
return AnalyzeImplicitConversions(S, E->getRHS()->IgnoreParenImpCasts(),
E->getOperatorLoc());
}
}
AnalyzeImplicitConversions(S, E->getRHS(), E->getOperatorLoc());
}
/// Diagnose an implicit cast; purely a helper for CheckImplicitConversion.
static void DiagnoseImpCast(Sema &S, Expr *E, QualType SourceType, QualType T,
SourceLocation CContext, unsigned diag,
bool pruneControlFlow = false) {
if (pruneControlFlow) {
S.DiagRuntimeBehavior(E->getExprLoc(), E,
S.PDiag(diag)
<< SourceType << T << E->getSourceRange()
<< SourceRange(CContext));
return;
}
S.Diag(E->getExprLoc(), diag)
<< SourceType << T << E->getSourceRange() << SourceRange(CContext);
}
/// Diagnose an implicit cast; purely a helper for CheckImplicitConversion.
static void DiagnoseImpCast(Sema &S, Expr *E, QualType T,
SourceLocation CContext, unsigned diag,
bool pruneControlFlow = false) {
DiagnoseImpCast(S, E, E->getType(), T, CContext, diag, pruneControlFlow);
}
/// Diagnose an implicit cast from a literal expression. Does not warn when the
/// cast wouldn't lose information.
void DiagnoseFloatingLiteralImpCast(Sema &S, FloatingLiteral *FL, QualType T,
SourceLocation CContext) {
// Try to convert the literal exactly to an integer. If we can, don't warn.
bool isExact = false;
const llvm::APFloat &Value = FL->getValue();
llvm::APSInt IntegerValue(S.Context.getIntWidth(T),
T->hasUnsignedIntegerRepresentation());
if (Value.convertToInteger(IntegerValue,
llvm::APFloat::rmTowardZero, &isExact)
== llvm::APFloat::opOK && isExact)
return;
SmallString<16> PrettySourceValue;
Value.toString(PrettySourceValue);
SmallString<16> PrettyTargetValue;
if (T->isSpecificBuiltinType(BuiltinType::Bool))
PrettyTargetValue = IntegerValue == 0 ? "false" : "true";
else
IntegerValue.toString(PrettyTargetValue);
S.Diag(FL->getExprLoc(), diag::warn_impcast_literal_float_to_integer)
<< FL->getType() << T.getUnqualifiedType() << PrettySourceValue
<< PrettyTargetValue << FL->getSourceRange() << SourceRange(CContext);
}
std::string PrettyPrintInRange(const llvm::APSInt &Value, IntRange Range) {
if (!Range.Width) return "0";
llvm::APSInt ValueInRange = Value;
ValueInRange.setIsSigned(!Range.NonNegative);
ValueInRange = ValueInRange.trunc(Range.Width);
return ValueInRange.toString(10);
}
void CheckImplicitConversion(Sema &S, Expr *E, QualType T,
SourceLocation CC, bool *ICContext = 0) {
if (E->isTypeDependent() || E->isValueDependent()) return;
const Type *Source = S.Context.getCanonicalType(E->getType()).getTypePtr();
const Type *Target = S.Context.getCanonicalType(T).getTypePtr();
if (Source == Target) return;
if (Target->isDependentType()) return;
// If the conversion context location is invalid don't complain. We also
// don't want to emit a warning if the issue occurs from the expansion of
// a system macro. The problem is that 'getSpellingLoc()' is slow, so we
// delay this check as long as possible. Once we detect we are in that
// scenario, we just return.
if (CC.isInvalid())
return;
// Diagnose implicit casts to bool.
if (Target->isSpecificBuiltinType(BuiltinType::Bool)) {
if (isa<StringLiteral>(E))
// Warn on string literal to bool. Checks for string literals in logical
// expressions, for instances, assert(0 && "error here"), is prevented
// by a check in AnalyzeImplicitConversions().
return DiagnoseImpCast(S, E, T, CC,
diag::warn_impcast_string_literal_to_bool);
if (Source->isFunctionType()) {
// Warn on function to bool. Checks free functions and static member
// functions. Weakly imported functions are excluded from the check,
// since it's common to test their value to check whether the linker
// found a definition for them.
ValueDecl *D = 0;
if (DeclRefExpr* R = dyn_cast<DeclRefExpr>(E)) {
D = R->getDecl();
} else if (MemberExpr *M = dyn_cast<MemberExpr>(E)) {
D = M->getMemberDecl();
}
if (D && !D->isWeak()) {
if (FunctionDecl* F = dyn_cast<FunctionDecl>(D)) {
S.Diag(E->getExprLoc(), diag::warn_impcast_function_to_bool)
<< F << E->getSourceRange() << SourceRange(CC);
S.Diag(E->getExprLoc(), diag::note_function_to_bool_silence)
<< FixItHint::CreateInsertion(E->getExprLoc(), "&");
QualType ReturnType;
UnresolvedSet<4> NonTemplateOverloads;
S.isExprCallable(*E, ReturnType, NonTemplateOverloads);
if (!ReturnType.isNull()
&& ReturnType->isSpecificBuiltinType(BuiltinType::Bool))
S.Diag(E->getExprLoc(), diag::note_function_to_bool_call)
<< FixItHint::CreateInsertion(
S.getPreprocessor().getLocForEndOfToken(E->getLocEnd()), "()");
return;
}
}
}
}
// Strip vector types.
if (isa<VectorType>(Source)) {
if (!isa<VectorType>(Target)) {
if (S.SourceMgr.isInSystemMacro(CC))
return;
return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_vector_scalar);
}
// If the vector cast is cast between two vectors of the same size, it is
// a bitcast, not a conversion.
if (S.Context.getTypeSize(Source) == S.Context.getTypeSize(Target))
return;
Source = cast<VectorType>(Source)->getElementType().getTypePtr();
Target = cast<VectorType>(Target)->getElementType().getTypePtr();
}
// Strip complex types.
if (isa<ComplexType>(Source)) {
if (!isa<ComplexType>(Target)) {
if (S.SourceMgr.isInSystemMacro(CC))
return;
return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_complex_scalar);
}
Source = cast<ComplexType>(Source)->getElementType().getTypePtr();
Target = cast<ComplexType>(Target)->getElementType().getTypePtr();
}
const BuiltinType *SourceBT = dyn_cast<BuiltinType>(Source);
const BuiltinType *TargetBT = dyn_cast<BuiltinType>(Target);
// If the source is floating point...
if (SourceBT && SourceBT->isFloatingPoint()) {
// ...and the target is floating point...
if (TargetBT && TargetBT->isFloatingPoint()) {
// ...then warn if we're dropping FP rank.
// Builtin FP kinds are ordered by increasing FP rank.
if (SourceBT->getKind() > TargetBT->getKind()) {
// Don't warn about float constants that are precisely
// representable in the target type.
Expr::EvalResult result;
if (E->EvaluateAsRValue(result, S.Context)) {
// Value might be a float, a float vector, or a float complex.
if (IsSameFloatAfterCast(result.Val,
S.Context.getFloatTypeSemantics(QualType(TargetBT, 0)),
S.Context.getFloatTypeSemantics(QualType(SourceBT, 0))))
return;
}
if (S.SourceMgr.isInSystemMacro(CC))
return;
DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_float_precision);
}
return;
}
// If the target is integral, always warn.
if (TargetBT && TargetBT->isInteger()) {
if (S.SourceMgr.isInSystemMacro(CC))
return;
Expr *InnerE = E->IgnoreParenImpCasts();
// We also want to warn on, e.g., "int i = -1.234"
if (UnaryOperator *UOp = dyn_cast<UnaryOperator>(InnerE))
if (UOp->getOpcode() == UO_Minus || UOp->getOpcode() == UO_Plus)
InnerE = UOp->getSubExpr()->IgnoreParenImpCasts();
if (FloatingLiteral *FL = dyn_cast<FloatingLiteral>(InnerE)) {
DiagnoseFloatingLiteralImpCast(S, FL, T, CC);
} else {
DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_float_integer);
}
}
return;
}
if ((E->isNullPointerConstant(S.Context, Expr::NPC_ValueDependentIsNotNull)
== Expr::NPCK_GNUNull) && !Target->isAnyPointerType()
&& !Target->isBlockPointerType() && !Target->isMemberPointerType()) {
SourceLocation Loc = E->getSourceRange().getBegin();
if (Loc.isMacroID())
Loc = S.SourceMgr.getImmediateExpansionRange(Loc).first;
if (!Loc.isMacroID() || CC.isMacroID())
S.Diag(Loc, diag::warn_impcast_null_pointer_to_integer)
<< T << clang::SourceRange(CC)
<< FixItHint::CreateReplacement(Loc, S.getFixItZeroLiteralForType(T));
}
if (!Source->isIntegerType() || !Target->isIntegerType())
return;
// TODO: remove this early return once the false positives for constant->bool
// in templates, macros, etc, are reduced or removed.
if (Target->isSpecificBuiltinType(BuiltinType::Bool))
return;
IntRange SourceRange = GetExprRange(S.Context, E);
IntRange TargetRange = IntRange::forTargetOfCanonicalType(S.Context, Target);
if (SourceRange.Width > TargetRange.Width) {
// If the source is a constant, use a default-on diagnostic.
// TODO: this should happen for bitfield stores, too.
llvm::APSInt Value(32);
if (E->isIntegerConstantExpr(Value, S.Context)) {
if (S.SourceMgr.isInSystemMacro(CC))
return;
std::string PrettySourceValue = Value.toString(10);
std::string PrettyTargetValue = PrettyPrintInRange(Value, TargetRange);
S.DiagRuntimeBehavior(E->getExprLoc(), E,
S.PDiag(diag::warn_impcast_integer_precision_constant)
<< PrettySourceValue << PrettyTargetValue
<< E->getType() << T << E->getSourceRange()
<< clang::SourceRange(CC));
return;
}
// People want to build with -Wshorten-64-to-32 and not -Wconversion.
if (S.SourceMgr.isInSystemMacro(CC))
return;
if (TargetRange.Width == 32 && S.Context.getIntWidth(E->getType()) == 64)
return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_integer_64_32,
/* pruneControlFlow */ true);
return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_integer_precision);
}
if ((TargetRange.NonNegative && !SourceRange.NonNegative) ||
(!TargetRange.NonNegative && SourceRange.NonNegative &&
SourceRange.Width == TargetRange.Width)) {
if (S.SourceMgr.isInSystemMacro(CC))
return;
unsigned DiagID = diag::warn_impcast_integer_sign;
// Traditionally, gcc has warned about this under -Wsign-compare.
// We also want to warn about it in -Wconversion.
// So if -Wconversion is off, use a completely identical diagnostic
// in the sign-compare group.
// The conditional-checking code will
if (ICContext) {
DiagID = diag::warn_impcast_integer_sign_conditional;
*ICContext = true;
}
return DiagnoseImpCast(S, E, T, CC, DiagID);
}
// Diagnose conversions between different enumeration types.
// In C, we pretend that the type of an EnumConstantDecl is its enumeration
// type, to give us better diagnostics.
QualType SourceType = E->getType();
if (!S.getLangOpts().CPlusPlus) {
if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E))
if (EnumConstantDecl *ECD = dyn_cast<EnumConstantDecl>(DRE->getDecl())) {
EnumDecl *Enum = cast<EnumDecl>(ECD->getDeclContext());
SourceType = S.Context.getTypeDeclType(Enum);
Source = S.Context.getCanonicalType(SourceType).getTypePtr();
}
}
if (const EnumType *SourceEnum = Source->getAs<EnumType>())
if (const EnumType *TargetEnum = Target->getAs<EnumType>())
if ((SourceEnum->getDecl()->getIdentifier() ||
SourceEnum->getDecl()->getTypedefNameForAnonDecl()) &&
(TargetEnum->getDecl()->getIdentifier() ||
TargetEnum->getDecl()->getTypedefNameForAnonDecl()) &&
SourceEnum != TargetEnum) {
if (S.SourceMgr.isInSystemMacro(CC))
return;
return DiagnoseImpCast(S, E, SourceType, T, CC,
diag::warn_impcast_different_enum_types);
}
return;
}
void CheckConditionalOperator(Sema &S, ConditionalOperator *E,
SourceLocation CC, QualType T);
void CheckConditionalOperand(Sema &S, Expr *E, QualType T,
SourceLocation CC, bool &ICContext) {
E = E->IgnoreParenImpCasts();
if (isa<ConditionalOperator>(E))
return CheckConditionalOperator(S, cast<ConditionalOperator>(E), CC, T);
AnalyzeImplicitConversions(S, E, CC);
if (E->getType() != T)
return CheckImplicitConversion(S, E, T, CC, &ICContext);
return;
}
void CheckConditionalOperator(Sema &S, ConditionalOperator *E,
SourceLocation CC, QualType T) {
AnalyzeImplicitConversions(S, E->getCond(), CC);
bool Suspicious = false;
CheckConditionalOperand(S, E->getTrueExpr(), T, CC, Suspicious);
CheckConditionalOperand(S, E->getFalseExpr(), T, CC, Suspicious);
// If -Wconversion would have warned about either of the candidates
// for a signedness conversion to the context type...
if (!Suspicious) return;
// ...but it's currently ignored...
if (S.Diags.getDiagnosticLevel(diag::warn_impcast_integer_sign_conditional,
CC))
return;
// ...then check whether it would have warned about either of the
// candidates for a signedness conversion to the condition type.
if (E->getType() == T) return;
Suspicious = false;
CheckImplicitConversion(S, E->getTrueExpr()->IgnoreParenImpCasts(),
E->getType(), CC, &Suspicious);
if (!Suspicious)
CheckImplicitConversion(S, E->getFalseExpr()->IgnoreParenImpCasts(),
E->getType(), CC, &Suspicious);
}
/// AnalyzeImplicitConversions - Find and report any interesting
/// implicit conversions in the given expression. There are a couple
/// of competing diagnostics here, -Wconversion and -Wsign-compare.
void AnalyzeImplicitConversions(Sema &S, Expr *OrigE, SourceLocation CC) {
QualType T = OrigE->getType();
Expr *E = OrigE->IgnoreParenImpCasts();
if (E->isTypeDependent() || E->isValueDependent())
return;
// For conditional operators, we analyze the arguments as if they
// were being fed directly into the output.
if (isa<ConditionalOperator>(E)) {
ConditionalOperator *CO = cast<ConditionalOperator>(E);
CheckConditionalOperator(S, CO, CC, T);
return;
}
// Go ahead and check any implicit conversions we might have skipped.
// The non-canonical typecheck is just an optimization;
// CheckImplicitConversion will filter out dead implicit conversions.
if (E->getType() != T)
CheckImplicitConversion(S, E, T, CC);
// Now continue drilling into this expression.
// Skip past explicit casts.
if (isa<ExplicitCastExpr>(E)) {
E = cast<ExplicitCastExpr>(E)->getSubExpr()->IgnoreParenImpCasts();
return AnalyzeImplicitConversions(S, E, CC);
}
if (BinaryOperator *BO = dyn_cast<BinaryOperator>(E)) {
// Do a somewhat different check with comparison operators.
if (BO->isComparisonOp())
return AnalyzeComparison(S, BO);
// And with simple assignments.
if (BO->getOpcode() == BO_Assign)
return AnalyzeAssignment(S, BO);
}
// These break the otherwise-useful invariant below. Fortunately,
// we don't really need to recurse into them, because any internal
// expressions should have been analyzed already when they were
// built into statements.
if (isa<StmtExpr>(E)) return;
// Don't descend into unevaluated contexts.
if (isa<UnaryExprOrTypeTraitExpr>(E)) return;
// Now just recurse over the expression's children.
CC = E->getExprLoc();
BinaryOperator *BO = dyn_cast<BinaryOperator>(E);
bool IsLogicalOperator = BO && BO->isLogicalOp();
for (Stmt::child_range I = E->children(); I; ++I) {
Expr *ChildExpr = dyn_cast_or_null<Expr>(*I);
if (!ChildExpr)
continue;
if (IsLogicalOperator &&
isa<StringLiteral>(ChildExpr->IgnoreParenImpCasts()))
// Ignore checking string literals that are in logical operators.
continue;
AnalyzeImplicitConversions(S, ChildExpr, CC);
}
}
} // end anonymous namespace
/// Diagnoses "dangerous" implicit conversions within the given
/// expression (which is a full expression). Implements -Wconversion
/// and -Wsign-compare.
///
/// \param CC the "context" location of the implicit conversion, i.e.
/// the most location of the syntactic entity requiring the implicit
/// conversion
void Sema::CheckImplicitConversions(Expr *E, SourceLocation CC) {
// Don't diagnose in unevaluated contexts.
if (ExprEvalContexts.back().Context == Sema::Unevaluated)
return;
// Don't diagnose for value- or type-dependent expressions.
if (E->isTypeDependent() || E->isValueDependent())
return;
// Check for array bounds violations in cases where the check isn't triggered
// elsewhere for other Expr types (like BinaryOperators), e.g. when an
// ArraySubscriptExpr is on the RHS of a variable initialization.
CheckArrayAccess(E);
// This is not the right CC for (e.g.) a variable initialization.
AnalyzeImplicitConversions(*this, E, CC);
}
void Sema::CheckBitFieldInitialization(SourceLocation InitLoc,
FieldDecl *BitField,
Expr *Init) {
(void) AnalyzeBitFieldAssignment(*this, BitField, Init, InitLoc);
}
/// CheckParmsForFunctionDef - Check that the parameters of the given
/// function are appropriate for the definition of a function. This
/// takes care of any checks that cannot be performed on the
/// declaration itself, e.g., that the types of each of the function
/// parameters are complete.
bool Sema::CheckParmsForFunctionDef(ParmVarDecl **P, ParmVarDecl **PEnd,
bool CheckParameterNames) {
bool HasInvalidParm = false;
for (; P != PEnd; ++P) {
ParmVarDecl *Param = *P;
// C99 6.7.5.3p4: the parameters in a parameter type list in a
// function declarator that is part of a function definition of
// that function shall not have incomplete type.
//
// This is also C++ [dcl.fct]p6.
if (!Param->isInvalidDecl() &&
RequireCompleteType(Param->getLocation(), Param->getType(),
diag::err_typecheck_decl_incomplete_type)) {
Param->setInvalidDecl();
HasInvalidParm = true;
}
// C99 6.9.1p5: If the declarator includes a parameter type list, the
// declaration of each parameter shall include an identifier.
if (CheckParameterNames &&
Param->getIdentifier() == 0 &&
!Param->isImplicit() &&
!getLangOpts().CPlusPlus)
Diag(Param->getLocation(), diag::err_parameter_name_omitted);
// C99 6.7.5.3p12:
// If the function declarator is not part of a definition of that
// function, parameters may have incomplete type and may use the [*]
// notation in their sequences of declarator specifiers to specify
// variable length array types.
QualType PType = Param->getOriginalType();
if (const ArrayType *AT = Context.getAsArrayType(PType)) {
if (AT->getSizeModifier() == ArrayType::Star) {
// FIXME: This diagnosic should point the the '[*]' if source-location
// information is added for it.
Diag(Param->getLocation(), diag::err_array_star_in_function_definition);
}
}
}
return HasInvalidParm;
}
/// CheckCastAlign - Implements -Wcast-align, which warns when a
/// pointer cast increases the alignment requirements.
void Sema::CheckCastAlign(Expr *Op, QualType T, SourceRange TRange) {
// This is actually a lot of work to potentially be doing on every
// cast; don't do it if we're ignoring -Wcast_align (as is the default).
if (getDiagnostics().getDiagnosticLevel(diag::warn_cast_align,
TRange.getBegin())
== DiagnosticsEngine::Ignored)
return;
// Ignore dependent types.
if (T->isDependentType() || Op->getType()->isDependentType())
return;
// Require that the destination be a pointer type.
const PointerType *DestPtr = T->getAs<PointerType>();
if (!DestPtr) return;
// If the destination has alignment 1, we're done.
QualType DestPointee = DestPtr->getPointeeType();
if (DestPointee->isIncompleteType()) return;
CharUnits DestAlign = Context.getTypeAlignInChars(DestPointee);
if (DestAlign.isOne()) return;
// Require that the source be a pointer type.
const PointerType *SrcPtr = Op->getType()->getAs<PointerType>();
if (!SrcPtr) return;
QualType SrcPointee = SrcPtr->getPointeeType();
// Whitelist casts from cv void*. We already implicitly
// whitelisted casts to cv void*, since they have alignment 1.
// Also whitelist casts involving incomplete types, which implicitly
// includes 'void'.
if (SrcPointee->isIncompleteType()) return;
CharUnits SrcAlign = Context.getTypeAlignInChars(SrcPointee);
if (SrcAlign >= DestAlign) return;
Diag(TRange.getBegin(), diag::warn_cast_align)
<< Op->getType() << T
<< static_cast<unsigned>(SrcAlign.getQuantity())
<< static_cast<unsigned>(DestAlign.getQuantity())
<< TRange << Op->getSourceRange();
}
static const Type* getElementType(const Expr *BaseExpr) {
const Type* EltType = BaseExpr->getType().getTypePtr();
if (EltType->isAnyPointerType())
return EltType->getPointeeType().getTypePtr();
else if (EltType->isArrayType())
return EltType->getBaseElementTypeUnsafe();
return EltType;
}
/// \brief Check whether this array fits the idiom of a size-one tail padded
/// array member of a struct.
///
/// We avoid emitting out-of-bounds access warnings for such arrays as they are
/// commonly used to emulate flexible arrays in C89 code.
static bool IsTailPaddedMemberArray(Sema &S, llvm::APInt Size,
const NamedDecl *ND) {
if (Size != 1 || !ND) return false;
const FieldDecl *FD = dyn_cast<FieldDecl>(ND);
if (!FD) return false;
// Don't consider sizes resulting from macro expansions or template argument
// substitution to form C89 tail-padded arrays.
TypeSourceInfo *TInfo = FD->getTypeSourceInfo();
while (TInfo) {
TypeLoc TL = TInfo->getTypeLoc();
// Look through typedefs.
const TypedefTypeLoc *TTL = dyn_cast<TypedefTypeLoc>(&TL);
if (TTL) {
const TypedefNameDecl *TDL = TTL->getTypedefNameDecl();
TInfo = TDL->getTypeSourceInfo();
continue;
}
ConstantArrayTypeLoc CTL = cast<ConstantArrayTypeLoc>(TL);
const Expr *SizeExpr = dyn_cast<IntegerLiteral>(CTL.getSizeExpr());
if (!SizeExpr || SizeExpr->getExprLoc().isMacroID())
return false;
break;
}
const RecordDecl *RD = dyn_cast<RecordDecl>(FD->getDeclContext());
if (!RD) return false;
if (RD->isUnion()) return false;
if (const CXXRecordDecl *CRD = dyn_cast<CXXRecordDecl>(RD)) {
if (!CRD->isStandardLayout()) return false;
}
// See if this is the last field decl in the record.
const Decl *D = FD;
while ((D = D->getNextDeclInContext()))
if (isa<FieldDecl>(D))
return false;
return true;
}
void Sema::CheckArrayAccess(const Expr *BaseExpr, const Expr *IndexExpr,
const ArraySubscriptExpr *ASE,
bool AllowOnePastEnd, bool IndexNegated) {
IndexExpr = IndexExpr->IgnoreParenImpCasts();
if (IndexExpr->isValueDependent())
return;
const Type *EffectiveType = getElementType(BaseExpr);
BaseExpr = BaseExpr->IgnoreParenCasts();
const ConstantArrayType *ArrayTy =
Context.getAsConstantArrayType(BaseExpr->getType());
if (!ArrayTy)
return;
llvm::APSInt index;
if (!IndexExpr->EvaluateAsInt(index, Context))
return;
if (IndexNegated)
index = -index;
const NamedDecl *ND = NULL;
if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(BaseExpr))
ND = dyn_cast<NamedDecl>(DRE->getDecl());
if (const MemberExpr *ME = dyn_cast<MemberExpr>(BaseExpr))
ND = dyn_cast<NamedDecl>(ME->getMemberDecl());
if (index.isUnsigned() || !index.isNegative()) {
llvm::APInt size = ArrayTy->getSize();
if (!size.isStrictlyPositive())
return;
const Type* BaseType = getElementType(BaseExpr);
if (BaseType != EffectiveType) {
// Make sure we're comparing apples to apples when comparing index to size
uint64_t ptrarith_typesize = Context.getTypeSize(EffectiveType);
uint64_t array_typesize = Context.getTypeSize(BaseType);
// Handle ptrarith_typesize being zero, such as when casting to void*
if (!ptrarith_typesize) ptrarith_typesize = 1;
if (ptrarith_typesize != array_typesize) {
// There's a cast to a different size type involved
uint64_t ratio = array_typesize / ptrarith_typesize;
// TODO: Be smarter about handling cases where array_typesize is not a
// multiple of ptrarith_typesize
if (ptrarith_typesize * ratio == array_typesize)
size *= llvm::APInt(size.getBitWidth(), ratio);
}
}
if (size.getBitWidth() > index.getBitWidth())
index = index.zext(size.getBitWidth());
else if (size.getBitWidth() < index.getBitWidth())
size = size.zext(index.getBitWidth());
// For array subscripting the index must be less than size, but for pointer
// arithmetic also allow the index (offset) to be equal to size since
// computing the next address after the end of the array is legal and
// commonly done e.g. in C++ iterators and range-based for loops.
if (AllowOnePastEnd ? index.ule(size) : index.ult(size))
return;
// Also don't warn for arrays of size 1 which are members of some
// structure. These are often used to approximate flexible arrays in C89
// code.
if (IsTailPaddedMemberArray(*this, size, ND))
return;
// Suppress the warning if the subscript expression (as identified by the
// ']' location) and the index expression are both from macro expansions
// within a system header.
if (ASE) {
SourceLocation RBracketLoc = SourceMgr.getSpellingLoc(
ASE->getRBracketLoc());
if (SourceMgr.isInSystemHeader(RBracketLoc)) {
SourceLocation IndexLoc = SourceMgr.getSpellingLoc(
IndexExpr->getLocStart());
if (SourceMgr.isFromSameFile(RBracketLoc, IndexLoc))
return;
}
}
unsigned DiagID = diag::warn_ptr_arith_exceeds_bounds;
if (ASE)
DiagID = diag::warn_array_index_exceeds_bounds;
DiagRuntimeBehavior(BaseExpr->getLocStart(), BaseExpr,
PDiag(DiagID) << index.toString(10, true)
<< size.toString(10, true)
<< (unsigned)size.getLimitedValue(~0U)
<< IndexExpr->getSourceRange());
} else {
unsigned DiagID = diag::warn_array_index_precedes_bounds;
if (!ASE) {
DiagID = diag::warn_ptr_arith_precedes_bounds;
if (index.isNegative()) index = -index;
}
DiagRuntimeBehavior(BaseExpr->getLocStart(), BaseExpr,
PDiag(DiagID) << index.toString(10, true)
<< IndexExpr->getSourceRange());
}
if (!ND) {
// Try harder to find a NamedDecl to point at in the note.
while (const ArraySubscriptExpr *ASE =
dyn_cast<ArraySubscriptExpr>(BaseExpr))
BaseExpr = ASE->getBase()->IgnoreParenCasts();
if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(BaseExpr))
ND = dyn_cast<NamedDecl>(DRE->getDecl());
if (const MemberExpr *ME = dyn_cast<MemberExpr>(BaseExpr))
ND = dyn_cast<NamedDecl>(ME->getMemberDecl());
}
if (ND)
DiagRuntimeBehavior(ND->getLocStart(), BaseExpr,
PDiag(diag::note_array_index_out_of_bounds)
<< ND->getDeclName());
}
void Sema::CheckArrayAccess(const Expr *expr) {
int AllowOnePastEnd = 0;
while (expr) {
expr = expr->IgnoreParenImpCasts();
switch (expr->getStmtClass()) {
case Stmt::ArraySubscriptExprClass: {
const ArraySubscriptExpr *ASE = cast<ArraySubscriptExpr>(expr);
CheckArrayAccess(ASE->getBase(), ASE->getIdx(), ASE,
AllowOnePastEnd > 0);
return;
}
case Stmt::UnaryOperatorClass: {
// Only unwrap the * and & unary operators
const UnaryOperator *UO = cast<UnaryOperator>(expr);
expr = UO->getSubExpr();
switch (UO->getOpcode()) {
case UO_AddrOf:
AllowOnePastEnd++;
break;
case UO_Deref:
AllowOnePastEnd--;
break;
default:
return;
}
break;
}
case Stmt::ConditionalOperatorClass: {
const ConditionalOperator *cond = cast<ConditionalOperator>(expr);
if (const Expr *lhs = cond->getLHS())
CheckArrayAccess(lhs);
if (const Expr *rhs = cond->getRHS())
CheckArrayAccess(rhs);
return;
}
default:
return;
}
}
}
//===--- CHECK: Objective-C retain cycles ----------------------------------//
namespace {
struct RetainCycleOwner {
RetainCycleOwner() : Variable(0), Indirect(false) {}
VarDecl *Variable;
SourceRange Range;
SourceLocation Loc;
bool Indirect;
void setLocsFrom(Expr *e) {
Loc = e->getExprLoc();
Range = e->getSourceRange();
}
};
}
/// Consider whether capturing the given variable can possibly lead to
/// a retain cycle.
static bool considerVariable(VarDecl *var, Expr *ref, RetainCycleOwner &owner) {
// In ARC, it's captured strongly iff the variable has __strong
// lifetime. In MRR, it's captured strongly if the variable is
// __block and has an appropriate type.
if (var->getType().getObjCLifetime() != Qualifiers::OCL_Strong)
return false;
owner.Variable = var;
owner.setLocsFrom(ref);
return true;
}
static bool findRetainCycleOwner(Sema &S, Expr *e, RetainCycleOwner &owner) {
while (true) {
e = e->IgnoreParens();
if (CastExpr *cast = dyn_cast<CastExpr>(e)) {
switch (cast->getCastKind()) {
case CK_BitCast:
case CK_LValueBitCast:
case CK_LValueToRValue:
case CK_ARCReclaimReturnedObject:
e = cast->getSubExpr();
continue;
default:
return false;
}
}
if (ObjCIvarRefExpr *ref = dyn_cast<ObjCIvarRefExpr>(e)) {
ObjCIvarDecl *ivar = ref->getDecl();
if (ivar->getType().getObjCLifetime() != Qualifiers::OCL_Strong)
return false;
// Try to find a retain cycle in the base.
if (!findRetainCycleOwner(S, ref->getBase(), owner))
return false;
if (ref->isFreeIvar()) owner.setLocsFrom(ref);
owner.Indirect = true;
return true;
}
if (DeclRefExpr *ref = dyn_cast<DeclRefExpr>(e)) {
VarDecl *var = dyn_cast<VarDecl>(ref->getDecl());
if (!var) return false;
return considerVariable(var, ref, owner);
}
if (MemberExpr *member = dyn_cast<MemberExpr>(e)) {
if (member->isArrow()) return false;
// Don't count this as an indirect ownership.
e = member->getBase();
continue;
}
if (PseudoObjectExpr *pseudo = dyn_cast<PseudoObjectExpr>(e)) {
// Only pay attention to pseudo-objects on property references.
ObjCPropertyRefExpr *pre
= dyn_cast<ObjCPropertyRefExpr>(pseudo->getSyntacticForm()
->IgnoreParens());
if (!pre) return false;
if (pre->isImplicitProperty()) return false;
ObjCPropertyDecl *property = pre->getExplicitProperty();
if (!property->isRetaining() &&
!(property->getPropertyIvarDecl() &&
property->getPropertyIvarDecl()->getType()
.getObjCLifetime() == Qualifiers::OCL_Strong))
return false;
owner.Indirect = true;
if (pre->isSuperReceiver()) {
owner.Variable = S.getCurMethodDecl()->getSelfDecl();
if (!owner.Variable)
return false;
owner.Loc = pre->getLocation();
owner.Range = pre->getSourceRange();
return true;
}
e = const_cast<Expr*>(cast<OpaqueValueExpr>(pre->getBase())
->getSourceExpr());
continue;
}
// Array ivars?
return false;
}
}
namespace {
struct FindCaptureVisitor : EvaluatedExprVisitor<FindCaptureVisitor> {
FindCaptureVisitor(ASTContext &Context, VarDecl *variable)
: EvaluatedExprVisitor<FindCaptureVisitor>(Context),
Variable(variable), Capturer(0) {}
VarDecl *Variable;
Expr *Capturer;
void VisitDeclRefExpr(DeclRefExpr *ref) {
if (ref->getDecl() == Variable && !Capturer)
Capturer = ref;
}
void VisitObjCIvarRefExpr(ObjCIvarRefExpr *ref) {
if (Capturer) return;
Visit(ref->getBase());
if (Capturer && ref->isFreeIvar())
Capturer = ref;
}
void VisitBlockExpr(BlockExpr *block) {
// Look inside nested blocks
if (block->getBlockDecl()->capturesVariable(Variable))
Visit(block->getBlockDecl()->getBody());
}
};
}
/// Check whether the given argument is a block which captures a
/// variable.
static Expr *findCapturingExpr(Sema &S, Expr *e, RetainCycleOwner &owner) {
assert(owner.Variable && owner.Loc.isValid());
e = e->IgnoreParenCasts();
BlockExpr *block = dyn_cast<BlockExpr>(e);
if (!block || !block->getBlockDecl()->capturesVariable(owner.Variable))
return 0;
FindCaptureVisitor visitor(S.Context, owner.Variable);
visitor.Visit(block->getBlockDecl()->getBody());
return visitor.Capturer;
}
static void diagnoseRetainCycle(Sema &S, Expr *capturer,
RetainCycleOwner &owner) {
assert(capturer);
assert(owner.Variable && owner.Loc.isValid());
S.Diag(capturer->getExprLoc(), diag::warn_arc_retain_cycle)
<< owner.Variable << capturer->getSourceRange();
S.Diag(owner.Loc, diag::note_arc_retain_cycle_owner)
<< owner.Indirect << owner.Range;
}
/// Check for a keyword selector that starts with the word 'add' or
/// 'set'.
static bool isSetterLikeSelector(Selector sel) {
if (sel.isUnarySelector()) return false;
StringRef str = sel.getNameForSlot(0);
while (!str.empty() && str.front() == '_') str = str.substr(1);
if (str.startswith("set"))
str = str.substr(3);
else if (str.startswith("add")) {
// Specially whitelist 'addOperationWithBlock:'.
if (sel.getNumArgs() == 1 && str.startswith("addOperationWithBlock"))
return false;
str = str.substr(3);
}
else
return false;
if (str.empty()) return true;
return !islower(str.front());
}
/// Check a message send to see if it's likely to cause a retain cycle.
void Sema::checkRetainCycles(ObjCMessageExpr *msg) {
// Only check instance methods whose selector looks like a setter.
if (!msg->isInstanceMessage() || !isSetterLikeSelector(msg->getSelector()))
return;
// Try to find a variable that the receiver is strongly owned by.
RetainCycleOwner owner;
if (msg->getReceiverKind() == ObjCMessageExpr::Instance) {
if (!findRetainCycleOwner(*this, msg->getInstanceReceiver(), owner))
return;
} else {
assert(msg->getReceiverKind() == ObjCMessageExpr::SuperInstance);
owner.Variable = getCurMethodDecl()->getSelfDecl();
owner.Loc = msg->getSuperLoc();
owner.Range = msg->getSuperLoc();
}
// Check whether the receiver is captured by any of the arguments.
for (unsigned i = 0, e = msg->getNumArgs(); i != e; ++i)
if (Expr *capturer = findCapturingExpr(*this, msg->getArg(i), owner))
return diagnoseRetainCycle(*this, capturer, owner);
}
/// Check a property assign to see if it's likely to cause a retain cycle.
void Sema::checkRetainCycles(Expr *receiver, Expr *argument) {
RetainCycleOwner owner;
if (!findRetainCycleOwner(*this, receiver, owner))
return;
if (Expr *capturer = findCapturingExpr(*this, argument, owner))
diagnoseRetainCycle(*this, capturer, owner);
}
bool Sema::checkUnsafeAssigns(SourceLocation Loc,
QualType LHS, Expr *RHS) {
Qualifiers::ObjCLifetime LT = LHS.getObjCLifetime();
if (LT != Qualifiers::OCL_Weak && LT != Qualifiers::OCL_ExplicitNone)
return false;
// strip off any implicit cast added to get to the one arc-specific
while (ImplicitCastExpr *cast = dyn_cast<ImplicitCastExpr>(RHS)) {
if (cast->getCastKind() == CK_ARCConsumeObject) {
Diag(Loc, diag::warn_arc_retained_assign)
<< (LT == Qualifiers::OCL_ExplicitNone)
<< RHS->getSourceRange();
return true;
}
RHS = cast->getSubExpr();
}
return false;
}
void Sema::checkUnsafeExprAssigns(SourceLocation Loc,
Expr *LHS, Expr *RHS) {
QualType LHSType;
// PropertyRef on LHS type need be directly obtained from
// its declaration as it has a PsuedoType.
ObjCPropertyRefExpr *PRE
= dyn_cast<ObjCPropertyRefExpr>(LHS->IgnoreParens());
if (PRE && !PRE->isImplicitProperty()) {
const ObjCPropertyDecl *PD = PRE->getExplicitProperty();
if (PD)
LHSType = PD->getType();
}
if (LHSType.isNull())
LHSType = LHS->getType();
if (checkUnsafeAssigns(Loc, LHSType, RHS))
return;
Qualifiers::ObjCLifetime LT = LHSType.getObjCLifetime();
// FIXME. Check for other life times.
if (LT != Qualifiers::OCL_None)
return;
if (PRE) {
if (PRE->isImplicitProperty())
return;
const ObjCPropertyDecl *PD = PRE->getExplicitProperty();
if (!PD)
return;
unsigned Attributes = PD->getPropertyAttributes();
if (Attributes & ObjCPropertyDecl::OBJC_PR_assign) {
// when 'assign' attribute was not explicitly specified
// by user, ignore it and rely on property type itself
// for lifetime info.
unsigned AsWrittenAttr = PD->getPropertyAttributesAsWritten();
if (!(AsWrittenAttr & ObjCPropertyDecl::OBJC_PR_assign) &&
LHSType->isObjCRetainableType())
return;
while (ImplicitCastExpr *cast = dyn_cast<ImplicitCastExpr>(RHS)) {
if (cast->getCastKind() == CK_ARCConsumeObject) {
Diag(Loc, diag::warn_arc_retained_property_assign)
<< RHS->getSourceRange();
return;
}
RHS = cast->getSubExpr();
}
}
}
}
//===--- CHECK: Empty statement body (-Wempty-body) ---------------------===//
namespace {
bool ShouldDiagnoseEmptyStmtBody(const SourceManager &SourceMgr,
SourceLocation StmtLoc,
const NullStmt *Body) {
// Do not warn if the body is a macro that expands to nothing, e.g:
//
// #define CALL(x)
// if (condition)
// CALL(0);
//
if (Body->hasLeadingEmptyMacro())
return false;
// Get line numbers of statement and body.
bool StmtLineInvalid;
unsigned StmtLine = SourceMgr.getSpellingLineNumber(StmtLoc,
&StmtLineInvalid);
if (StmtLineInvalid)
return false;
bool BodyLineInvalid;
unsigned BodyLine = SourceMgr.getSpellingLineNumber(Body->getSemiLoc(),
&BodyLineInvalid);
if (BodyLineInvalid)
return false;
// Warn if null statement and body are on the same line.
if (StmtLine != BodyLine)
return false;
return true;
}
} // Unnamed namespace
void Sema::DiagnoseEmptyStmtBody(SourceLocation StmtLoc,
const Stmt *Body,
unsigned DiagID) {
// Since this is a syntactic check, don't emit diagnostic for template
// instantiations, this just adds noise.
if (CurrentInstantiationScope)
return;
// The body should be a null statement.
const NullStmt *NBody = dyn_cast<NullStmt>(Body);
if (!NBody)
return;
// Do the usual checks.
if (!ShouldDiagnoseEmptyStmtBody(SourceMgr, StmtLoc, NBody))
return;
Diag(NBody->getSemiLoc(), DiagID);
Diag(NBody->getSemiLoc(), diag::note_empty_body_on_separate_line);
}
void Sema::DiagnoseEmptyLoopBody(const Stmt *S,
const Stmt *PossibleBody) {
assert(!CurrentInstantiationScope); // Ensured by caller
SourceLocation StmtLoc;
const Stmt *Body;
unsigned DiagID;
if (const ForStmt *FS = dyn_cast<ForStmt>(S)) {
StmtLoc = FS->getRParenLoc();
Body = FS->getBody();
DiagID = diag::warn_empty_for_body;
} else if (const WhileStmt *WS = dyn_cast<WhileStmt>(S)) {
StmtLoc = WS->getCond()->getSourceRange().getEnd();
Body = WS->getBody();
DiagID = diag::warn_empty_while_body;
} else
return; // Neither `for' nor `while'.
// The body should be a null statement.
const NullStmt *NBody = dyn_cast<NullStmt>(Body);
if (!NBody)
return;
// Skip expensive checks if diagnostic is disabled.
if (Diags.getDiagnosticLevel(DiagID, NBody->getSemiLoc()) ==
DiagnosticsEngine::Ignored)
return;
// Do the usual checks.
if (!ShouldDiagnoseEmptyStmtBody(SourceMgr, StmtLoc, NBody))
return;
// `for(...);' and `while(...);' are popular idioms, so in order to keep
// noise level low, emit diagnostics only if for/while is followed by a
// CompoundStmt, e.g.:
// for (int i = 0; i < n; i++);
// {
// a(i);
// }
// or if for/while is followed by a statement with more indentation
// than for/while itself:
// for (int i = 0; i < n; i++);
// a(i);
bool ProbableTypo = isa<CompoundStmt>(PossibleBody);
if (!ProbableTypo) {
bool BodyColInvalid;
unsigned BodyCol = SourceMgr.getPresumedColumnNumber(
PossibleBody->getLocStart(),
&BodyColInvalid);
if (BodyColInvalid)
return;
bool StmtColInvalid;
unsigned StmtCol = SourceMgr.getPresumedColumnNumber(
S->getLocStart(),
&StmtColInvalid);
if (StmtColInvalid)
return;
if (BodyCol > StmtCol)
ProbableTypo = true;
}
if (ProbableTypo) {
Diag(NBody->getSemiLoc(), DiagID);
Diag(NBody->getSemiLoc(), diag::note_empty_body_on_separate_line);
}
}
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