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[UBsan] Skip -fsanitize=vptr instrumentations when the pointer value is null. 

Otherwise -fsanitize=vptr causes the program to crash when it downcasts
a null pointer.

Reviewed in http://reviews.llvm.org/D4412.
Patch by Byoungyoung Lee!

llvm-svn: 213393
This commit is contained in:
Alexey Samsonov 2014-07-18 18:15:39 +00:00
parent 6c12414358
commit 32f59d8e1e
2 changed files with 7 additions and 1 deletions
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2
clang/lib/CodeGen/CGExpr.cpp
View File

@ -463,7 +463,7 @@ void CodeGenFunction::EmitTypeCheck(TypeCheckKind TCK, SourceLocation Loc,
llvm::Value *Cond = nullptr;
llvm::BasicBlock *Done = nullptr;
if (SanOpts->Null) {
if (SanOpts->Null || TCK == TCK_DowncastPointer) {
// The glvalue must not be an empty glvalue.
Cond = Builder.CreateICmpNE(
Address, llvm::Constant::getNullValue(Address->getType()));

6
clang/test/CodeGenCXX/catch-undef-behavior.cpp
View File

@ -1,5 +1,6 @@
// RUN: %clang_cc1 -std=c++11 -fsanitize=signed-integer-overflow,integer-divide-by-zero,float-divide-by-zero,shift,unreachable,return,vla-bound,alignment,null,vptr,object-size,float-cast-overflow,bool,enum,array-bounds,function -emit-llvm %s -o - -triple x86_64-linux-gnu | FileCheck %s
// RUN: %clang_cc1 -std=c++11 -fsanitize=vptr,address -emit-llvm %s -o - -triple x86_64-linux-gnu | FileCheck %s --check-prefix=CHECK-ASAN
// RUN: %clang_cc1 -std=c++11 -fsanitize=vptr -emit-llvm %s -o - -triple x86_64-linux-gnu | FileCheck %s --check-prefix=DOWNCAST-NULL
struct S {
double d;
@ -190,10 +191,15 @@ int bad_enum_value() {
}
// CHECK-LABEL: @_Z20bad_downcast_pointer
// DOWNCAST-NULL-LABEL: @_Z20bad_downcast_pointer
void bad_downcast_pointer(S *p) {
// CHECK: %[[NONNULL:.*]] = icmp ne {{.*}}, null
// CHECK: br i1 %[[NONNULL]],
// A null poiner access is guarded without -fsanitize=null.
// DOWNCAST-NULL: %[[NONNULL:.*]] = icmp ne {{.*}}, null
// DOWNCAST-NULL: br i1 %[[NONNULL]],
// CHECK: %[[SIZE:.*]] = call i64 @llvm.objectsize.i64.p0i8(
// CHECK: %[[E1:.*]] = icmp uge i64 %[[SIZE]], 24
// CHECK: %[[MISALIGN:.*]] = and i64 %{{.*}}, 7