r294800 - Don't let EvaluationModes dictate whether an invalid base is OK
George Burgess IV via cfe-commits
cfe-commits at lists.llvm.org
Fri Feb 10 14:52:29 PST 2017
Author: gbiv
Date: Fri Feb 10 16:52:29 2017
New Revision: 294800
URL: http://llvm.org/viewvc/llvm-project?rev=294800&view=rev
Log:
Don't let EvaluationModes dictate whether an invalid base is OK
What we want to actually control this behavior is something more local
than an EvalutationMode. Please see the linked revision for more
discussion on why/etc.
This fixes PR31843.
Differential Revision: https://reviews.llvm.org/D29469
Modified:
cfe/trunk/lib/AST/ExprConstant.cpp
cfe/trunk/test/CodeGen/object-size.c
cfe/trunk/test/Sema/builtin-object-size.c
Modified: cfe/trunk/lib/AST/ExprConstant.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/AST/ExprConstant.cpp?rev=294800&r1=294799&r2=294800&view=diff
==============================================================================
--- cfe/trunk/lib/AST/ExprConstant.cpp (original)
+++ cfe/trunk/lib/AST/ExprConstant.cpp Fri Feb 10 16:52:29 2017
@@ -616,10 +616,12 @@ namespace {
/// gets a chance to look at it.
EM_PotentialConstantExpressionUnevaluated,
- /// Evaluate as a constant expression. Continue evaluating if either:
- /// - We find a MemberExpr with a base that can't be evaluated.
- /// - We find a variable initialized with a call to a function that has
- /// the alloc_size attribute on it.
+ /// Evaluate as a constant expression. In certain scenarios, if:
+ /// - we find a MemberExpr with a base that can't be evaluated, or
+ /// - we find a variable initialized with a call to a function that has
+ /// the alloc_size attribute on it
+ /// then we may consider evaluation to have succeeded.
+ ///
/// In either case, the LValue returned shall have an invalid base; in the
/// former, the base will be the invalid MemberExpr, in the latter, the
/// base will be either the alloc_size CallExpr or a CastExpr wrapping
@@ -902,10 +904,6 @@ namespace {
return KeepGoing;
}
- bool allowInvalidBaseExpr() const {
- return EvalMode == EM_OffsetFold;
- }
-
class ArrayInitLoopIndex {
EvalInfo &Info;
uint64_t OuterIndex;
@@ -1416,8 +1414,10 @@ static bool Evaluate(APValue &Result, Ev
static bool EvaluateInPlace(APValue &Result, EvalInfo &Info,
const LValue &This, const Expr *E,
bool AllowNonLiteralTypes = false);
-static bool EvaluateLValue(const Expr *E, LValue &Result, EvalInfo &Info);
-static bool EvaluatePointer(const Expr *E, LValue &Result, EvalInfo &Info);
+static bool EvaluateLValue(const Expr *E, LValue &Result, EvalInfo &Info,
+ bool InvalidBaseOK = false);
+static bool EvaluatePointer(const Expr *E, LValue &Result, EvalInfo &Info,
+ bool InvalidBaseOK = false);
static bool EvaluateMemberPointer(const Expr *E, MemberPtr &Result,
EvalInfo &Info);
static bool EvaluateTemporary(const Expr *E, LValue &Result, EvalInfo &Info);
@@ -4835,6 +4835,7 @@ class LValueExprEvaluatorBase
: public ExprEvaluatorBase<Derived> {
protected:
LValue &Result;
+ bool InvalidBaseOK;
typedef LValueExprEvaluatorBase LValueExprEvaluatorBaseTy;
typedef ExprEvaluatorBase<Derived> ExprEvaluatorBaseTy;
@@ -4843,9 +4844,14 @@ protected:
return true;
}
+ bool evaluatePointer(const Expr *E, LValue &Result) {
+ return EvaluatePointer(E, Result, this->Info, InvalidBaseOK);
+ }
+
public:
- LValueExprEvaluatorBase(EvalInfo &Info, LValue &Result) :
- ExprEvaluatorBaseTy(Info), Result(Result) {}
+ LValueExprEvaluatorBase(EvalInfo &Info, LValue &Result, bool InvalidBaseOK)
+ : ExprEvaluatorBaseTy(Info), Result(Result),
+ InvalidBaseOK(InvalidBaseOK) {}
bool Success(const APValue &V, const Expr *E) {
Result.setFrom(this->Info.Ctx, V);
@@ -4857,7 +4863,7 @@ public:
QualType BaseTy;
bool EvalOK;
if (E->isArrow()) {
- EvalOK = EvaluatePointer(E->getBase(), Result, this->Info);
+ EvalOK = evaluatePointer(E->getBase(), Result);
BaseTy = E->getBase()->getType()->castAs<PointerType>()->getPointeeType();
} else if (E->getBase()->isRValue()) {
assert(E->getBase()->getType()->isRecordType());
@@ -4868,7 +4874,7 @@ public:
BaseTy = E->getBase()->getType();
}
if (!EvalOK) {
- if (!this->Info.allowInvalidBaseExpr())
+ if (!InvalidBaseOK)
return false;
Result.setInvalid(E);
return true;
@@ -4962,8 +4968,8 @@ namespace {
class LValueExprEvaluator
: public LValueExprEvaluatorBase<LValueExprEvaluator> {
public:
- LValueExprEvaluator(EvalInfo &Info, LValue &Result) :
- LValueExprEvaluatorBaseTy(Info, Result) {}
+ LValueExprEvaluator(EvalInfo &Info, LValue &Result, bool InvalidBaseOK) :
+ LValueExprEvaluatorBaseTy(Info, Result, InvalidBaseOK) {}
bool VisitVarDecl(const Expr *E, const VarDecl *VD);
bool VisitUnaryPreIncDec(const UnaryOperator *UO);
@@ -5016,10 +5022,11 @@ public:
/// * function designators in C, and
/// * "extern void" objects
/// * @selector() expressions in Objective-C
-static bool EvaluateLValue(const Expr *E, LValue &Result, EvalInfo &Info) {
+static bool EvaluateLValue(const Expr *E, LValue &Result, EvalInfo &Info,
+ bool InvalidBaseOK) {
assert(E->isGLValue() || E->getType()->isFunctionType() ||
E->getType()->isVoidType() || isa<ObjCSelectorExpr>(E));
- return LValueExprEvaluator(Info, Result).Visit(E);
+ return LValueExprEvaluator(Info, Result, InvalidBaseOK).Visit(E);
}
bool LValueExprEvaluator::VisitDeclRefExpr(const DeclRefExpr *E) {
@@ -5180,7 +5187,7 @@ bool LValueExprEvaluator::VisitArraySubs
if (E->getBase()->getType()->isVectorType())
return Error(E);
- if (!EvaluatePointer(E->getBase(), Result, Info))
+ if (!evaluatePointer(E->getBase(), Result))
return false;
APSInt Index;
@@ -5191,7 +5198,7 @@ bool LValueExprEvaluator::VisitArraySubs
}
bool LValueExprEvaluator::VisitUnaryDeref(const UnaryOperator *E) {
- return EvaluatePointer(E->getSubExpr(), Result, Info);
+ return evaluatePointer(E->getSubExpr(), Result);
}
bool LValueExprEvaluator::VisitUnaryReal(const UnaryOperator *E) {
@@ -5339,7 +5346,7 @@ static bool getBytesReturnedByAllocSizeC
/// and mark Result's Base as invalid.
static bool evaluateLValueAsAllocSize(EvalInfo &Info, APValue::LValueBase Base,
LValue &Result) {
- if (!Info.allowInvalidBaseExpr() || Base.isNull())
+ if (Base.isNull())
return false;
// Because we do no form of static analysis, we only support const variables.
@@ -5373,17 +5380,27 @@ namespace {
class PointerExprEvaluator
: public ExprEvaluatorBase<PointerExprEvaluator> {
LValue &Result;
+ bool InvalidBaseOK;
bool Success(const Expr *E) {
Result.set(E);
return true;
}
+ bool evaluateLValue(const Expr *E, LValue &Result) {
+ return EvaluateLValue(E, Result, Info, InvalidBaseOK);
+ }
+
+ bool evaluatePointer(const Expr *E, LValue &Result) {
+ return EvaluatePointer(E, Result, Info, InvalidBaseOK);
+ }
+
bool visitNonBuiltinCallExpr(const CallExpr *E);
public:
- PointerExprEvaluator(EvalInfo &info, LValue &Result)
- : ExprEvaluatorBaseTy(info), Result(Result) {}
+ PointerExprEvaluator(EvalInfo &info, LValue &Result, bool InvalidBaseOK)
+ : ExprEvaluatorBaseTy(info), Result(Result),
+ InvalidBaseOK(InvalidBaseOK) {}
bool Success(const APValue &V, const Expr *E) {
Result.setFrom(Info.Ctx, V);
@@ -5430,9 +5447,10 @@ public:
};
} // end anonymous namespace
-static bool EvaluatePointer(const Expr* E, LValue& Result, EvalInfo &Info) {
+static bool EvaluatePointer(const Expr* E, LValue& Result, EvalInfo &Info,
+ bool InvalidBaseOK) {
assert(E->isRValue() && E->getType()->hasPointerRepresentation());
- return PointerExprEvaluator(Info, Result).Visit(E);
+ return PointerExprEvaluator(Info, Result, InvalidBaseOK).Visit(E);
}
bool PointerExprEvaluator::VisitBinaryOperator(const BinaryOperator *E) {
@@ -5445,7 +5463,7 @@ bool PointerExprEvaluator::VisitBinaryOp
if (IExp->getType()->isPointerType())
std::swap(PExp, IExp);
- bool EvalPtrOK = EvaluatePointer(PExp, Result, Info);
+ bool EvalPtrOK = evaluatePointer(PExp, Result);
if (!EvalPtrOK && !Info.noteFailure())
return false;
@@ -5461,7 +5479,7 @@ bool PointerExprEvaluator::VisitBinaryOp
}
bool PointerExprEvaluator::VisitUnaryAddrOf(const UnaryOperator *E) {
- return EvaluateLValue(E->getSubExpr(), Result, Info);
+ return evaluateLValue(E->getSubExpr(), Result);
}
bool PointerExprEvaluator::VisitCastExpr(const CastExpr* E) {
@@ -5495,7 +5513,7 @@ bool PointerExprEvaluator::VisitCastExpr
case CK_DerivedToBase:
case CK_UncheckedDerivedToBase:
- if (!EvaluatePointer(E->getSubExpr(), Result, Info))
+ if (!evaluatePointer(E->getSubExpr(), Result))
return false;
if (!Result.Base && Result.Offset.isZero())
return true;
@@ -5542,7 +5560,7 @@ bool PointerExprEvaluator::VisitCastExpr
}
case CK_ArrayToPointerDecay:
if (SubExpr->isGLValue()) {
- if (!EvaluateLValue(SubExpr, Result, Info))
+ if (!evaluateLValue(SubExpr, Result))
return false;
} else {
Result.set(SubExpr, Info.CurrentCall->Index);
@@ -5559,18 +5577,19 @@ bool PointerExprEvaluator::VisitCastExpr
return true;
case CK_FunctionToPointerDecay:
- return EvaluateLValue(SubExpr, Result, Info);
+ return evaluateLValue(SubExpr, Result);
case CK_LValueToRValue: {
LValue LVal;
- if (!EvaluateLValue(E->getSubExpr(), LVal, Info))
+ if (!evaluateLValue(E->getSubExpr(), LVal))
return false;
APValue RVal;
// Note, we use the subexpression's type in order to retain cv-qualifiers.
if (!handleLValueToRValueConversion(Info, E, E->getSubExpr()->getType(),
LVal, RVal))
- return evaluateLValueAsAllocSize(Info, LVal.Base, Result);
+ return InvalidBaseOK &&
+ evaluateLValueAsAllocSize(Info, LVal.Base, Result);
return Success(RVal, E);
}
}
@@ -5615,7 +5634,7 @@ bool PointerExprEvaluator::visitNonBuilt
if (ExprEvaluatorBaseTy::VisitCallExpr(E))
return true;
- if (!(Info.allowInvalidBaseExpr() && getAllocSizeAttr(E)))
+ if (!(InvalidBaseOK && getAllocSizeAttr(E)))
return false;
Result.setInvalid(E);
@@ -5638,12 +5657,12 @@ bool PointerExprEvaluator::VisitBuiltinC
unsigned BuiltinOp) {
switch (BuiltinOp) {
case Builtin::BI__builtin_addressof:
- return EvaluateLValue(E->getArg(0), Result, Info);
+ return evaluateLValue(E->getArg(0), Result);
case Builtin::BI__builtin_assume_aligned: {
// We need to be very careful here because: if the pointer does not have the
// asserted alignment, then the behavior is undefined, and undefined
// behavior is non-constant.
- if (!EvaluatePointer(E->getArg(0), Result, Info))
+ if (!evaluatePointer(E->getArg(0), Result))
return false;
LValue OffsetResult(Result);
@@ -6279,7 +6298,7 @@ class TemporaryExprEvaluator
: public LValueExprEvaluatorBase<TemporaryExprEvaluator> {
public:
TemporaryExprEvaluator(EvalInfo &Info, LValue &Result) :
- LValueExprEvaluatorBaseTy(Info, Result) {}
+ LValueExprEvaluatorBaseTy(Info, Result, false) {}
/// Visit an expression which constructs the value of this temporary.
bool VisitConstructExpr(const Expr *E) {
@@ -7383,7 +7402,8 @@ static bool tryEvaluateBuiltinObjectSize
if (!EvaluateAsRValue(Info, E, RVal))
return false;
LVal.setFrom(Info.Ctx, RVal);
- } else if (!EvaluatePointer(ignorePointerCastsAndParens(E), LVal, Info))
+ } else if (!EvaluatePointer(ignorePointerCastsAndParens(E), LVal, Info,
+ /*InvalidBaseOK=*/true))
return false;
}
Modified: cfe/trunk/test/CodeGen/object-size.c
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGen/object-size.c?rev=294800&r1=294799&r2=294800&view=diff
==============================================================================
--- cfe/trunk/test/CodeGen/object-size.c (original)
+++ cfe/trunk/test/CodeGen/object-size.c Fri Feb 10 16:52:29 2017
@@ -549,3 +549,22 @@ int incomplete_and_function_types() {
// CHECK: store i32 0
gi = __builtin_object_size(incomplete_char_array, 3);
}
+
+// Flips between the pointer and lvalue evaluator a lot.
+void deeply_nested() {
+ struct {
+ struct {
+ struct {
+ struct {
+ int e[2];
+ char f; // Inhibit our writing-off-the-end check
+ } d[2];
+ } c[2];
+ } b[2];
+ } *a;
+
+ // CHECK: store i32 4
+ gi = __builtin_object_size(&a->b[1].c[1].d[1].e[1], 1);
+ // CHECK: store i32 4
+ gi = __builtin_object_size(&a->b[1].c[1].d[1].e[1], 3);
+}
Modified: cfe/trunk/test/Sema/builtin-object-size.c
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Sema/builtin-object-size.c?rev=294800&r1=294799&r2=294800&view=diff
==============================================================================
--- cfe/trunk/test/Sema/builtin-object-size.c (original)
+++ cfe/trunk/test/Sema/builtin-object-size.c Fri Feb 10 16:52:29 2017
@@ -76,3 +76,18 @@ int pr28314(void) {
a += __builtin_object_size(p3->b, 0);
return a;
}
+
+int pr31843() {
+ int n = 0;
+
+ struct { int f; } a;
+ int b;
+ n += __builtin_object_size(({&(b ? &a : &a)->f; pr31843;}), 0); // expected-warning{{expression result unused}}
+
+ struct statfs { char f_mntonname[1024];};
+ struct statfs *outStatFSBuf;
+ n += __builtin_object_size(outStatFSBuf->f_mntonname ? "" : "", 1); // expected-warning{{address of array}}
+ n += __builtin_object_size(outStatFSBuf->f_mntonname ?: "", 1);
+
+ return n;
+}
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