vsk created this revision.
Adding these helpers will make a planned change simpler:
[ubsan] Defer pointer type checks, then try to skip the redundant ones
https://reviews.llvm.org/D37543
Files:
lib/CodeGen/CGExpr.cpp
lib/CodeGen/CodeGenFunction.h
Index: lib/CodeGen/CodeGenFunction.h
===================================================================
--- lib/CodeGen/CodeGenFunction.h
+++ lib/CodeGen/CodeGenFunction.h
@@ -2347,6 +2347,12 @@
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;
Index: lib/CodeGen/CGExpr.cpp
===================================================================
--- lib/CodeGen/CGExpr.cpp
+++ lib/CodeGen/CGExpr.cpp
@@ -569,6 +569,19 @@
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 @@
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 @@
// 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) {
Index: lib/CodeGen/CodeGenFunction.h
===================================================================
--- lib/CodeGen/CodeGenFunction.h
+++ lib/CodeGen/CodeGenFunction.h
@@ -2347,6 +2347,12 @@
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;
Index: lib/CodeGen/CGExpr.cpp
===================================================================
--- lib/CodeGen/CGExpr.cpp
+++ lib/CodeGen/CGExpr.cpp
@@ -569,6 +569,19 @@
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 @@
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 @@
// 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) {
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