forked from OSchip/llvm-project
Add -Wloop-analysis. This warning will fire on for loops which the variables
in the loop conditional do not change. llvm-svn: 155835
This commit is contained in:
Richard Trieu
parent
d427d51c2b
commit
451a5db01b
|
|
@ -14,6 +14,12 @@
|
|||
let Component = "Sema" in {
|
||||
let CategoryName = "Semantic Issue" in {
|
||||
|
||||
// For loop analysis
|
||||
def warn_variables_not_in_loop_body : Warning<
|
||||
"variable%select{s| %1|s %1 and %2|s %1 %2 and %3|s %1 %2 %3 and %4}0 "
|
||||
"used in loop condition not modified in loop body">,
|
||||
InGroup<DiagGroup<"loop-analysis">>, DefaultIgnore;
|
||||
|
||||
// Constant expressions
|
||||
def err_expr_not_ice : Error<
|
||||
"expression is not an %select{integer|integral}0 constant expression">;
|
||||
|
|
|
|||
|
|
@ -19,6 +19,7 @@
|
|||
#include "clang/AST/ASTContext.h"
|
||||
#include "clang/AST/CharUnits.h"
|
||||
#include "clang/AST/DeclObjC.h"
|
||||
#include "clang/AST/EvaluatedExprVisitor.h"
|
||||
#include "clang/AST/ExprCXX.h"
|
||||
#include "clang/AST/ExprObjC.h"
|
||||
#include "clang/AST/StmtObjC.h"
|
||||
|
|
@ -28,6 +29,7 @@
|
|||
#include "clang/Basic/TargetInfo.h"
|
||||
#include "llvm/ADT/ArrayRef.h"
|
||||
#include "llvm/ADT/STLExtras.h"
|
||||
#include "llvm/ADT/SmallPtrSet.h"
|
||||
#include "llvm/ADT/SmallVector.h"
|
||||
using namespace clang;
|
||||
using namespace sema;
|
||||
|
|
@ -1037,6 +1039,218 @@ Sema::ActOnDoStmt(SourceLocation DoLoc, Stmt *Body,
|
|||
return Owned(new (Context) DoStmt(Body, Cond, DoLoc, WhileLoc, CondRParen));
|
||||
}
|
||||
|
||||
namespace {
|
||||
// This visitor will traverse a conditional statement and store all
|
||||
// the evaluated decls into a vector. Simple is set to true if none
|
||||
// of the excluded constructs are used.
|
||||
class DeclExtractor : public EvaluatedExprVisitor<DeclExtractor> {
|
||||
llvm::SmallPtrSet<VarDecl*, 8> &Decls;
|
||||
llvm::SmallVector<SourceRange, 10> &Ranges;
|
||||
bool Simple;
|
||||
PartialDiagnostic &PDiag;
|
||||
public:
|
||||
typedef EvaluatedExprVisitor<DeclExtractor> Inherited;
|
||||
|
||||
DeclExtractor(Sema &S, llvm::SmallPtrSet<VarDecl*, 8> &Decls,
|
||||
llvm::SmallVector<SourceRange, 10> &Ranges,
|
||||
PartialDiagnostic &PDiag) :
|
||||
Inherited(S.Context),
|
||||
Decls(Decls),
|
||||
Ranges(Ranges),
|
||||
Simple(true),
|
||||
PDiag(PDiag) {}
|
||||
|
||||
bool isSimple() { return Simple; }
|
||||
|
||||
// Replaces the method in EvaluatedExprVisitor.
|
||||
void VisitMemberExpr(MemberExpr* E) {
|
||||
Simple = false;
|
||||
}
|
||||
|
||||
// Any Stmt not whitelisted will cause the condition to be marked complex.
|
||||
void VisitStmt(Stmt *S) {
|
||||
Simple = false;
|
||||
}
|
||||
|
||||
void VisitBinaryOperator(BinaryOperator *E) {
|
||||
Visit(E->getLHS());
|
||||
Visit(E->getRHS());
|
||||
}
|
||||
|
||||
void VisitCastExpr(CastExpr *E) {
|
||||
Visit(E->getSubExpr());
|
||||
}
|
||||
|
||||
void VisitUnaryOperator(UnaryOperator *E) {
|
||||
// Skip checking conditionals with derefernces.
|
||||
if (E->getOpcode() == UO_Deref)
|
||||
Simple = false;
|
||||
else
|
||||
Visit(E->getSubExpr());
|
||||
}
|
||||
|
||||
void VisitConditionalOperator(ConditionalOperator *E) {
|
||||
Visit(E->getCond());
|
||||
Visit(E->getTrueExpr());
|
||||
Visit(E->getFalseExpr());
|
||||
}
|
||||
|
||||
void VisitParenExpr(ParenExpr *E) {
|
||||
Visit(E->getSubExpr());
|
||||
}
|
||||
|
||||
void VisitBinaryConditionalOperator(BinaryConditionalOperator *E) {
|
||||
Visit(E->getOpaqueValue()->getSourceExpr());
|
||||
Visit(E->getFalseExpr());
|
||||
}
|
||||
|
||||
void VisitIntegerLiteral(IntegerLiteral *E) { }
|
||||
void VisitFloatingLiteral(FloatingLiteral *E) { }
|
||||
void VisitCXXBoolLiteralExpr(CXXBoolLiteralExpr *E) { }
|
||||
void VisitCharacterLiteral(CharacterLiteral *E) { }
|
||||
void VisitGNUNullExpr(GNUNullExpr *E) { }
|
||||
void VisitImaginaryLiteral(ImaginaryLiteral *E) { }
|
||||
|
||||
void VisitDeclRefExpr(DeclRefExpr *E) {
|
||||
VarDecl *VD = dyn_cast<VarDecl>(E->getDecl());
|
||||
if (!VD) return;
|
||||
|
||||
Ranges.push_back(E->getSourceRange());
|
||||
|
||||
Decls.insert(VD);
|
||||
}
|
||||
|
||||
}; // end class DeclExtractor
|
||||
|
||||
// DeclMatcher checks to see if the decls are used in a non-evauluated
|
||||
// context.
|
||||
class DeclMatcher : public EvaluatedExprVisitor<DeclMatcher> {
|
||||
llvm::SmallPtrSet<VarDecl*, 8> &Decls;
|
||||
bool FoundDecl;
|
||||
//bool EvalDecl;
|
||||
|
||||
public:
|
||||
typedef EvaluatedExprVisitor<DeclMatcher> Inherited;
|
||||
|
||||
DeclMatcher(Sema &S, llvm::SmallPtrSet<VarDecl*, 8> &Decls, Stmt *Statement) :
|
||||
Inherited(S.Context), Decls(Decls), FoundDecl(false) {
|
||||
if (!Statement) return;
|
||||
|
||||
Visit(Statement);
|
||||
}
|
||||
|
||||
void VisitReturnStmt(ReturnStmt *S) {
|
||||
FoundDecl = true;
|
||||
}
|
||||
|
||||
void VisitBreakStmt(BreakStmt *S) {
|
||||
FoundDecl = true;
|
||||
}
|
||||
|
||||
void VisitGotoStmt(GotoStmt *S) {
|
||||
FoundDecl = true;
|
||||
}
|
||||
|
||||
void VisitCastExpr(CastExpr *E) {
|
||||
if (E->getCastKind() == CK_LValueToRValue)
|
||||
CheckLValueToRValueCast(E->getSubExpr());
|
||||
else
|
||||
Visit(E->getSubExpr());
|
||||
}
|
||||
|
||||
void CheckLValueToRValueCast(Expr *E) {
|
||||
E = E->IgnoreParenImpCasts();
|
||||
|
||||
if (isa<DeclRefExpr>(E)) {
|
||||
return;
|
||||
}
|
||||
|
||||
if (ConditionalOperator *CO = dyn_cast<ConditionalOperator>(E)) {
|
||||
Visit(CO->getCond());
|
||||
CheckLValueToRValueCast(CO->getTrueExpr());
|
||||
CheckLValueToRValueCast(CO->getFalseExpr());
|
||||
return;
|
||||
}
|
||||
|
||||
if (BinaryConditionalOperator *BCO =
|
||||
dyn_cast<BinaryConditionalOperator>(E)) {
|
||||
CheckLValueToRValueCast(BCO->getOpaqueValue()->getSourceExpr());
|
||||
CheckLValueToRValueCast(BCO->getFalseExpr());
|
||||
return;
|
||||
}
|
||||
|
||||
Visit(E);
|
||||
}
|
||||
|
||||
void VisitDeclRefExpr(DeclRefExpr *E) {
|
||||
if (VarDecl *VD = dyn_cast<VarDecl>(E->getDecl()))
|
||||
if (Decls.count(VD))
|
||||
FoundDecl = true;
|
||||
}
|
||||
|
||||
bool FoundDeclInUse() { return FoundDecl; }
|
||||
|
||||
}; // end class DeclMatcher
|
||||
|
||||
void CheckForLoopConditionalStatement(Sema &S, Expr *Second,
|
||||
Expr *Third, Stmt *Body) {
|
||||
// Condition is empty
|
||||
if (!Second) return;
|
||||
|
||||
if (S.Diags.getDiagnosticLevel(diag::warn_variables_not_in_loop_body,
|
||||
Second->getLocStart())
|
||||
== DiagnosticsEngine::Ignored)
|
||||
return;
|
||||
|
||||
PartialDiagnostic PDiag = S.PDiag(diag::warn_variables_not_in_loop_body);
|
||||
llvm::SmallPtrSet<VarDecl*, 8> Decls;
|
||||
llvm::SmallVector<SourceRange, 10> Ranges;
|
||||
DeclExtractor DE(S, Decls, Ranges, PDiag);
|
||||
DE.Visit(Second);
|
||||
|
||||
// Don't analyze complex conditionals.
|
||||
if (!DE.isSimple()) return;
|
||||
|
||||
// No decls found.
|
||||
if (Decls.size() == 0) return;
|
||||
|
||||
// Don't warn on volatile decls.
|
||||
for (llvm::SmallPtrSet<VarDecl*, 8>::iterator I = Decls.begin(),
|
||||
E = Decls.end();
|
||||
I != E; ++I)
|
||||
if ((*I)->getType().isVolatileQualified()) return;
|
||||
|
||||
if (DeclMatcher(S, Decls, Second).FoundDeclInUse() ||
|
||||
DeclMatcher(S, Decls, Third).FoundDeclInUse() ||
|
||||
DeclMatcher(S, Decls, Body).FoundDeclInUse())
|
||||
return;
|
||||
|
||||
// Load decl names into diagnostic.
|
||||
if (Decls.size() > 4)
|
||||
PDiag << 0;
|
||||
else {
|
||||
PDiag << Decls.size();
|
||||
for (llvm::SmallPtrSet<VarDecl*, 8>::iterator I = Decls.begin(),
|
||||
E = Decls.end();
|
||||
I != E; ++I)
|
||||
PDiag << (*I)->getDeclName();
|
||||
}
|
||||
|
||||
// Load SourceRanges into diagnostic if there is room.
|
||||
// Otherwise, load the SourceRange of the conditional expression.
|
||||
if (Ranges.size() <= PartialDiagnostic::MaxArguments)
|
||||
for (llvm::SmallVector<SourceRange, 10>::iterator I = Ranges.begin(),
|
||||
E = Ranges.end();
|
||||
I != E; ++I)
|
||||
PDiag << *I;
|
||||
else
|
||||
PDiag << Second->getSourceRange();
|
||||
|
||||
S.Diag(Ranges.begin()->getBegin(), PDiag);
|
||||
}
|
||||
|
||||
} // end namespace
|
||||
|
||||
StmtResult
|
||||
Sema::ActOnForStmt(SourceLocation ForLoc, SourceLocation LParenLoc,
|
||||
Stmt *First, FullExprArg second, Decl *secondVar,
|
||||
|
|
@ -1059,6 +1273,8 @@ Sema::ActOnForStmt(SourceLocation ForLoc, SourceLocation LParenLoc,
|
|||
}
|
||||
}
|
||||
|
||||
CheckForLoopConditionalStatement(*this, second.get(), third.get(), Body);
|
||||
|
||||
ExprResult SecondResult(second.release());
|
||||
VarDecl *ConditionVar = 0;
|
||||
if (secondVar) {
|
||||
|
|
|
|||
|
|
@ -0,0 +1,146 @@
|
|||
// RUN: %clang_cc1 -fsyntax-only -Wloop-analysis -verify %s
|
||||
|
||||
struct S {
|
||||
bool stop() { return false; }
|
||||
bool keep_running;
|
||||
};
|
||||
|
||||
void by_ref(int &value) { }
|
||||
void by_value(int value) { }
|
||||
void by_pointer(int *value) {}
|
||||
|
||||
void test1() {
|
||||
S s;
|
||||
for (; !s.stop();) {}
|
||||
for (; s.keep_running;) {}
|
||||
for (int i; i < 1; ++i) {}
|
||||
for (int i; i < 1; ) {} // expected-warning {{variable 'i' used in loop condition not modified in loop body}}
|
||||
for (int i; i < 1; ) { ++i; }
|
||||
for (int i; i < 1; ) { return; }
|
||||
for (int i; i < 1; ) { break; }
|
||||
for (int i; i < 1; ) { goto exit_loop; }
|
||||
exit_loop:
|
||||
for (int i; i < 1; ) { by_ref(i); }
|
||||
for (int i; i < 1; ) { by_value(i); } // expected-warning {{variable 'i' used in loop condition not modified in loop body}}
|
||||
for (int i; i < 1; ) { by_pointer(&i); }
|
||||
|
||||
for (int i; i < 1; ++i)
|
||||
for (int j; j < 1; ++j)
|
||||
{ }
|
||||
for (int i; i < 1; ++i)
|
||||
for (int j; j < 1; ++i) // expected-warning {{variable 'j' used in loop condition not modified in loop body}}
|
||||
{ }
|
||||
for (int i; i < 1; ++i)
|
||||
for (int j; i < 1; ++j) // expected-warning {{variable 'i' used in loop condition not modified in loop body}}
|
||||
{ }
|
||||
|
||||
for (int *i, *j; i < j; ++i) {}
|
||||
for (int *i, *j; i < j;) {} // expected-warning {{variables 'i' and 'j' used in loop condition not modified in loop body}}
|
||||
|
||||
// Dereferencing pointers is ignored for now.
|
||||
for (int *i; *i; ) {}
|
||||
}
|
||||
|
||||
void test2() {
|
||||
int i, j, k;
|
||||
int *ptr;
|
||||
|
||||
// Testing CastExpr
|
||||
for (; i; ) {} // expected-warning {{variable 'i' used in loop condition not modified in loop body}}
|
||||
for (; i; ) { i = 5; }
|
||||
|
||||
// Testing BinaryOperator
|
||||
for (; i < j; ) {} // expected-warning {{variables 'i' and 'j' used in loop condition not modified in loop body}}
|
||||
for (; i < j; ) { i = 5; }
|
||||
for (; i < j; ) { j = 5; }
|
||||
|
||||
// Testing IntegerLiteral
|
||||
for (; i < 5; ) {} // expected-warning {{variable 'i' used in loop condition not modified in loop body}}
|
||||
for (; i < 5; ) { i = 5; }
|
||||
|
||||
// Testing FloatingLiteral
|
||||
for (; i < 5.0; ) {} // expected-warning {{variable 'i' used in loop condition not modified in loop body}}
|
||||
for (; i < 5.0; ) { i = 5; }
|
||||
|
||||
// Testing CharacterLiteral
|
||||
for (; i == 'a'; ) {} // expected-warning {{variable 'i' used in loop condition not modified in loop body}}
|
||||
for (; i == 'a'; ) { i = 5; }
|
||||
|
||||
// Testing CXXBoolLiteralExpr
|
||||
for (; i == true; ) {} // expected-warning {{variable 'i' used in loop condition not modified in loop body}}
|
||||
for (; i == true; ) { i = 5; }
|
||||
|
||||
// Testing GNUNullExpr
|
||||
for (; ptr == __null; ) {} // expected-warning {{variable 'ptr' used in loop condition not modified in loop body}}
|
||||
for (; ptr == __null; ) { ptr = &i; }
|
||||
|
||||
// Testing UnaryOperator
|
||||
for (; -i > 5; ) {} // expected-warning {{variable 'i' used in loop condition not modified in loop body}}
|
||||
for (; -i > 5; ) { ++i; }
|
||||
|
||||
// Testing ImaginaryLiteral
|
||||
for (; i != 3i; ) {} // expected-warning {{variable 'i' used in loop condition not modified in loop body}}
|
||||
for (; i != 3i; ) { ++i; }
|
||||
|
||||
// Testing ConditionalOperator
|
||||
for (; i ? j : k; ) {} // expected-warning {{variables 'i' 'j' and 'k' used in loop condition not modified in loop body}}
|
||||
for (; i ? j : k; ) { ++i; }
|
||||
for (; i ? j : k; ) { ++j; }
|
||||
for (; i ? j : k; ) { ++k; }
|
||||
for (; i; ) { j = i ? i : i; } // expected-warning {{variable 'i' used in loop condition not modified in loop body}}
|
||||
for (; i; ) { j = (i = 1) ? i : i; }
|
||||
for (; i; ) { j = i ? i : ++i; }
|
||||
|
||||
// Testing BinaryConditionalOperator
|
||||
for (; i ?: j; ) {} // expected-warning {{variables 'i' and 'j' used in loop condition not modified in loop body}}
|
||||
for (; i ?: j; ) { ++i; }
|
||||
for (; i ?: j; ) { ++j; }
|
||||
for (; i; ) { j = i ?: i; } // expected-warning {{variable 'i' used in loop condition not modified in loop body}}
|
||||
|
||||
// Testing ParenExpr
|
||||
for (; (i); ) { } // expected-warning {{variable 'i' used in loop condition not modified in loop body}}
|
||||
for (; (i); ) { ++i; }
|
||||
|
||||
// Testing non-evaluated variables
|
||||
for (; i < sizeof(j); ) { } // expected-warning {{variable 'i' used in loop condition not modified in loop body}}
|
||||
for (; i < sizeof(j); ) { ++j; } // expected-warning {{variable 'i' used in loop condition not modified in loop body}}
|
||||
for (; i < sizeof(j); ) { ++i; }
|
||||
}
|
||||
|
||||
// False positive and how to silence.
|
||||
void test3() {
|
||||
int x;
|
||||
int *ptr = &x;
|
||||
for (;x<5;) { *ptr = 6; } // expected-warning {{variable 'x' used in loop condition not modified in loop body}}
|
||||
|
||||
for (;x<5;) {
|
||||
*ptr = 6;
|
||||
(void)x;
|
||||
}
|
||||
}
|
||||
|
||||
// Check ordering and printing of variables. Max variables is currently 4.
|
||||
void test4() {
|
||||
int a, b, c, d, e, f;
|
||||
for (; a;); // expected-warning {{variable 'a' used in loop condition not modified in loop body}}
|
||||
for (; a + b;); // expected-warning {{variables 'a' and 'b' used in loop condition not modified in loop body}}
|
||||
for (; a + b + c;); // expected-warning {{variables 'a' 'b' and 'c' used in loop condition not modified in loop body}}
|
||||
for (; a + b + c + d;); // expected-warning {{variables 'a' 'b' 'c' and 'd' used in loop condition not modified in loop body}}
|
||||
for (; a + b + c + d + e;); // expected-warning {{variables used in loop condition not modified in loop body}}
|
||||
for (; a + b + c + d + e + f;); // expected-warning {{variables used in loop condition not modified in loop body}}
|
||||
for (; a + c + d + b;); // expected-warning {{variables 'a' 'c' 'd' and 'b' used in loop condition not modified in loop body}}
|
||||
for (; d + c + b + a;); // expected-warning {{variables 'd' 'c' 'b' and 'a' used in loop condition not modified in loop body}}
|
||||
}
|
||||
|
||||
// Ensure that the warning doesn't fail when lots of variables are used
|
||||
// in the conditional.
|
||||
void test5() {
|
||||
for (int a; a+a+a+a+a+a+a+a+a+a;); // \
|
||||
// expected-warning {{variable 'a' used in loop condition not modified in loop body}}
|
||||
for (int a; a+a+a+a+a+a+a+a+a+a+a;); // \
|
||||
// expected-warning {{variable 'a' used in loop condition not modified in loop body}}
|
||||
for (int a; a+a+a+a+a+a+a+a+a+a+a+a+a+a+a+a+a+a+a+a;); // \
|
||||
// expected-warning {{variable 'a' used in loop condition not modified in loop body}}
|
||||
for (int a; a+a+a+a+a+a+a+a+a+a+a+a+a+a+a+a+a+a+a+a+a+a+a+a+a+a+a+a+a+a;);//\
|
||||
// expected-warning {{variable 'a' used in loop condition not modified in loop body}}
|
||||
}
|
||||
Loading…
Reference in New Issue