Author: vedantk
Date: Mon Oct 2 18:27:25 2017
New Revision: 314750
URL: http://llvm.org/viewvc/llvm-project?rev=314750&view=rev
Log:
[ubsan] Add helpers to decide when null/vptr checks are required. NFC.
Modified:
cfe/trunk/lib/CodeGen/CGExpr.cpp
cfe/trunk/lib/CodeGen/CodeGenFunction.h
Modified: cfe/trunk/lib/CodeGen/CGExpr.cpp
URL:
http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CGExpr.cpp?rev=314750&r1=314749&r2=314750&view=diff
==============================================================================
--- cfe/trunk/lib/CodeGen/CGExpr.cpp (original)
+++ cfe/trunk/lib/CodeGen/CGExpr.cpp Mon Oct 2 18:27:25 2017
@@ -569,6 +569,19 @@ static llvm::Value *emitHash16Bytes(CGBu
return Builder.CreateMul(B1, KMul);
}
+bool CodeGenFunction::isNullPointerAllowed(TypeCheckKind TCK) {
+ return TCK == TCK_DowncastPointer || TCK == TCK_Upcast ||
+ TCK == TCK_UpcastToVirtualBase;
+}
+
+bool CodeGenFunction::isVptrCheckRequired(TypeCheckKind TCK, QualType Ty) {
+ CXXRecordDecl *RD = Ty->getAsCXXRecordDecl();
+ return (RD && RD->hasDefinition() && RD->isDynamicClass()) &&
+ (TCK == TCK_MemberAccess || TCK == TCK_MemberCall ||
+ TCK == TCK_DowncastPointer || TCK == TCK_DowncastReference ||
+ TCK == TCK_UpcastToVirtualBase);
+}
+
bool CodeGenFunction::sanitizePerformTypeCheck() const {
return SanOpts.has(SanitizerKind::Null) |
SanOpts.has(SanitizerKind::Alignment) |
@@ -608,8 +621,7 @@ void CodeGenFunction::EmitTypeCheck(Type
llvm::Value *IsNonNull = nullptr;
bool IsGuaranteedNonNull =
SkippedChecks.has(SanitizerKind::Null) || PtrToAlloca;
- bool AllowNullPointers = TCK == TCK_DowncastPointer || TCK == TCK_Upcast ||
- TCK == TCK_UpcastToVirtualBase;
+ bool AllowNullPointers = isNullPointerAllowed(TCK);
if ((SanOpts.has(SanitizerKind::Null) || AllowNullPointers) &&
!IsGuaranteedNonNull) {
// The glvalue must not be an empty glvalue.
@@ -696,13 +708,8 @@ void CodeGenFunction::EmitTypeCheck(Type
// The program has undefined behavior if:
// -- the [pointer or glvalue] is used to access a non-static data member
// or call a non-static member function
- CXXRecordDecl *RD = Ty->getAsCXXRecordDecl();
if (SanOpts.has(SanitizerKind::Vptr) &&
- !SkippedChecks.has(SanitizerKind::Vptr) &&
- (TCK == TCK_MemberAccess || TCK == TCK_MemberCall ||
- TCK == TCK_DowncastPointer || TCK == TCK_DowncastReference ||
- TCK == TCK_UpcastToVirtualBase) &&
- RD && RD->hasDefinition() && RD->isDynamicClass()) {
+ !SkippedChecks.has(SanitizerKind::Vptr) && isVptrCheckRequired(TCK, Ty))
{
// Ensure that the pointer is non-null before loading it. If there is no
// compile-time guarantee, reuse the run-time null check or emit a new one.
if (!IsGuaranteedNonNull) {
Modified: cfe/trunk/lib/CodeGen/CodeGenFunction.h
URL:
http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CodeGenFunction.h?rev=314750&r1=314749&r2=314750&view=diff
==============================================================================
--- cfe/trunk/lib/CodeGen/CodeGenFunction.h (original)
+++ cfe/trunk/lib/CodeGen/CodeGenFunction.h Mon Oct 2 18:27:25 2017
@@ -2356,6 +2356,12 @@ public:
TCK_NonnullAssign
};
+ /// Determine whether the pointer type check \p TCK permits null pointers.
+ static bool isNullPointerAllowed(TypeCheckKind TCK);
+
+ /// Determine whether the pointer type check \p TCK requires a vptr check.
+ static bool isVptrCheckRequired(TypeCheckKind TCK, QualType Ty);
+
/// \brief Whether any type-checking sanitizers are enabled. If \c false,
/// calls to EmitTypeCheck can be skipped.
bool sanitizePerformTypeCheck() const;
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