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Sema: constify EvalAddr, EvalVal 

Propagate const throughout these methods as they are non-mutating analyzers of
state.  NFC.

llvm-svn: 260864
This commit is contained in:
Saleem Abdulrasool 2016-02-15 00:36:49 +00:00
parent 226232044a
commit 768eb4aa42
1 changed files with 145 additions and 138 deletions
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283
clang/lib/Sema/SemaChecking.cpp
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@ -5818,10 +5818,12 @@ void Sema::CheckStrncatArguments(const CallExpr *CE,
//===--- 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);
static const Expr *EvalVal(const Expr *E,
SmallVectorImpl<const DeclRefExpr *> &refVars,
const Decl *ParentDecl);
static const Expr *EvalAddr(const Expr *E,
SmallVectorImpl<const DeclRefExpr *> &refVars,
const Decl *ParentDecl);
/// CheckReturnStackAddr - Check if a return statement returns the address
/// of a stack variable.
@ -5829,8 +5831,8 @@ static void
CheckReturnStackAddr(Sema &S, Expr *RetValExp, QualType lhsType,
SourceLocation ReturnLoc) {
Expr *stackE = nullptr;
SmallVector<DeclRefExpr *, 8> refVars;
const Expr *stackE = nullptr;
SmallVector<const DeclRefExpr *, 8> refVars;
// Perform checking for returned stack addresses, local blocks,
// label addresses or references to temporaries.
@ -5858,7 +5860,8 @@ CheckReturnStackAddr(Sema &S, Expr *RetValExp, QualType lhsType,
diagRange = refVars[0]->getSourceRange();
}
if (DeclRefExpr *DR = dyn_cast<DeclRefExpr>(stackE)) { //address of local var.
if (const DeclRefExpr *DR = dyn_cast<DeclRefExpr>(stackE)) {
// address of local var
S.Diag(diagLoc, diag::warn_ret_stack_addr_ref) << lhsType->isReferenceType()
<< DR->getDecl()->getDeclName() << diagRange;
} else if (isa<BlockExpr>(stackE)) { // local block.
@ -5873,12 +5876,12 @@ CheckReturnStackAddr(Sema &S, Expr *RetValExp, QualType lhsType,
// 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());
const 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();
SourceRange range = (i < e - 1) ? refVars[i + 1]->getSourceRange()
: stackE->getSourceRange();
S.Diag(VD->getLocation(), diag::note_ref_var_local_bind)
<< VD->getDeclName() << range;
}
@ -5910,8 +5913,9 @@ CheckReturnStackAddr(Sema &S, Expr *RetValExp, QualType lhsType,
/// * 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) {
static const Expr *EvalAddr(const Expr *E,
SmallVectorImpl<const DeclRefExpr *> &refVars,
const Decl *ParentDecl) {
if (E->isTypeDependent())
return nullptr;
@ -5928,13 +5932,13 @@ static Expr *EvalAddr(Expr *E, SmallVectorImpl<DeclRefExpr *> &refVars,
// EvalAddr and EvalVal appropriately.
switch (E->getStmtClass()) {
case Stmt::DeclRefExprClass: {
DeclRefExpr *DR = cast<DeclRefExpr>(E);
const DeclRefExpr *DR = cast<DeclRefExpr>(E);
// If we leave the immediate function, the lifetime isn't about to end.
if (DR->refersToEnclosingVariableOrCapture())
return nullptr;
if (VarDecl *V = dyn_cast<VarDecl>(DR->getDecl()))
if (const 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() &&
@ -5950,44 +5954,44 @@ static Expr *EvalAddr(Expr *E, SmallVectorImpl<DeclRefExpr *> &refVars,
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);
const UnaryOperator *U = cast<UnaryOperator>(E);
if (U->getOpcode() == UO_AddrOf)
return EvalVal(U->getSubExpr(), refVars, ParentDecl);
else
return nullptr;
return nullptr;
}
case Stmt::BinaryOperatorClass: {
// Handle pointer arithmetic. All other binary operators are not valid
// in this context.
BinaryOperator *B = cast<BinaryOperator>(E);
const BinaryOperator *B = cast<BinaryOperator>(E);
BinaryOperatorKind op = B->getOpcode();
if (op != BO_Add && op != BO_Sub)
return nullptr;
Expr *Base = B->getLHS();
const 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();
if (!Base->getType()->isPointerType())
Base = B->getRHS();
assert (Base->getType()->isPointerType());
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);
const ConditionalOperator *C = cast<ConditionalOperator>(E);
// Handle the GNU extension for missing LHS.
// FIXME: That isn't a ConditionalOperator, so doesn't get here.
if (Expr *LHSExpr = C->getLHS()) {
if (const 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))
if (const Expr *LHS = EvalAddr(LHSExpr, refVars, ParentDecl))
return LHS;
}
@ -6020,7 +6024,7 @@ static Expr *EvalAddr(Expr *E, SmallVectorImpl<DeclRefExpr *> &refVars,
case Stmt::CXXDynamicCastExprClass:
case Stmt::CXXConstCastExprClass:
case Stmt::CXXReinterpretCastExprClass: {
Expr* SubExpr = cast<CastExpr>(E)->getSubExpr();
const Expr* SubExpr = cast<CastExpr>(E)->getSubExpr();
switch (cast<CastExpr>(E)->getCastKind()) {
case CK_LValueToRValue:
case CK_NoOp:
@ -6050,13 +6054,12 @@ static Expr *EvalAddr(Expr *E, SmallVectorImpl<DeclRefExpr *> &refVars,
}
case Stmt::MaterializeTemporaryExprClass:
if (Expr *Result = EvalAddr(
cast<MaterializeTemporaryExpr>(E)->GetTemporaryExpr(),
refVars, ParentDecl))
if (const Expr *Result =
EvalAddr(cast<MaterializeTemporaryExpr>(E)->GetTemporaryExpr(),
refVars, ParentDecl))
return Result;
return E;
// Everything else: we simply don't reason about them.
default:
return nullptr;
@ -6065,141 +6068,145 @@ static Expr *EvalAddr(Expr *E, SmallVectorImpl<DeclRefExpr *> &refVars,
/// 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).
static const Expr *EvalVal(const Expr *E,
SmallVectorImpl<const DeclRefExpr *> &refVars,
const 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.
// 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 nullptr;
}
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 we leave the immediate function, the lifetime isn't about to end.
if (DR->refersToEnclosingVariableOrCapture())
E = E->IgnoreParens();
switch (E->getStmtClass()) {
case Stmt::ImplicitCastExprClass: {
const ImplicitCastExpr *IE = cast<ImplicitCastExpr>(E);
if (IE->getValueKind() == VK_LValue) {
E = IE->getSubExpr();
continue;
}
return nullptr;
}
if (VarDecl *V = dyn_cast<VarDecl>(DR->getDecl())) {
// Check if it refers to itself, e.g. "int& i = i;".
if (V == ParentDecl)
return DR;
case Stmt::ExprWithCleanupsClass:
return EvalVal(cast<ExprWithCleanups>(E)->getSubExpr(), refVars,
ParentDecl);
if (V->hasLocalStorage()) {
if (!V->getType()->isReferenceType())
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.
const DeclRefExpr *DR = cast<DeclRefExpr>(E);
// If we leave the immediate function, the lifetime isn't about to end.
if (DR->refersToEnclosingVariableOrCapture())
return nullptr;
if (const VarDecl *V = dyn_cast<VarDecl>(DR->getDecl())) {
// Check if it refers to itself, e.g. "int& i = i;".
if (V == ParentDecl)
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);
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 nullptr;
}
return nullptr;
}
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.
const UnaryOperator *U = cast<UnaryOperator>(E);
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);
if (U->getOpcode() == UO_Deref)
return EvalAddr(U->getSubExpr(), refVars, ParentDecl);
return nullptr;
}
return nullptr;
}
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::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::OMPArraySectionExprClass: {
return EvalAddr(cast<OMPArraySectionExpr>(E)->getBase(), refVars,
ParentDecl);
}
case Stmt::OMPArraySectionExprClass: {
return EvalAddr(cast<OMPArraySectionExpr>(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.
const ConditionalOperator *C = cast<ConditionalOperator>(E);
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 (const Expr *LHSExpr = C->getLHS()) {
// In C++, we can have a throw-expression, which has 'void' type.
if (!LHSExpr->getType()->isVoidType())
if (const Expr *LHS = EvalVal(LHSExpr, refVars, ParentDecl))
return LHS;
}
// 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 = EvalVal(LHSExpr, refVars, ParentDecl))
return LHS;
if (C->getRHS()->getType()->isVoidType())
return nullptr;
return EvalVal(C->getRHS(), refVars, ParentDecl);
}
// In C++, we can have a throw-expression, which has 'void' type.
if (C->getRHS()->getType()->isVoidType())
return nullptr;
// Accesses to members are potential references to data on the stack.
case Stmt::MemberExprClass: {
const MemberExpr *M = cast<MemberExpr>(E);
return EvalVal(C->getRHS(), refVars, ParentDecl);
}
// Check for indirect access. We only want direct field accesses.
if (M->isArrow())
return nullptr;
// Accesses to members are potential references to data on the stack.
case Stmt::MemberExprClass: {
MemberExpr *M = cast<MemberExpr>(E);
// 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 nullptr;
// Check for indirect access. We only want direct field accesses.
if (M->isArrow())
return nullptr;
return EvalVal(M->getBase(), refVars, ParentDecl);
}
// 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 nullptr;
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())
case Stmt::MaterializeTemporaryExprClass:
if (const Expr *Result =
EvalVal(cast<MaterializeTemporaryExpr>(E)->GetTemporaryExpr(),
refVars, ParentDecl))
return Result;
return E;
// Everything else: we simply don't reason about them.
return nullptr;
}
} while (true);
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 nullptr;
}
} while (true);
}
void