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-fcatch-undefined-behavior: Start checking loads and stores for null pointers. 

We want the diagnostic, and if the load is optimized away, we still want to
trap it. Stop checking non-default address spaces; that doesn't work in
general.

llvm-svn: 167219
This commit is contained in:
Richard Smith 2012-11-01 07:22:08 +00:00
parent c89e75e93e
commit 2d8b294b3c
2 changed files with 25 additions and 15 deletions
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22
clang/lib/CodeGen/CGExpr.cpp
View File

@ -479,15 +479,17 @@ void CodeGenFunction::EmitTypeCheck(TypeCheckKind TCK, SourceLocation Loc,
if (!CatchUndefined)
return;
// Don't check pointers outside the default address space. The null check
// isn't correct, the object-size check isn't supported by LLVM, and we can't
// communicate the addresses to the runtime handler for the vptr check.
if (Address->getType()->getPointerAddressSpace())
return;
llvm::Value *Cond = 0;
if (TCK != TCK_Load && TCK != TCK_Store) {
// The glvalue must not be an empty glvalue. Don't bother checking this for
// loads and stores, because we will get a segfault anyway (if the operation
// isn't optimized out).
Cond = Builder.CreateICmpNE(
Address, llvm::Constant::getNullValue(Address->getType()));
}
// The glvalue must not be an empty glvalue.
Cond = Builder.CreateICmpNE(
Address, llvm::Constant::getNullValue(Address->getType()));
uint64_t AlignVal = Alignment.getQuantity();
@ -496,16 +498,14 @@ void CodeGenFunction::EmitTypeCheck(TypeCheckKind TCK, SourceLocation Loc,
if (!AlignVal)
AlignVal = getContext().getTypeAlignInChars(Ty).getQuantity();
// This needs to be to the standard address space.
Address = Builder.CreateBitCast(Address, Int8PtrTy);
// The glvalue must refer to a large enough storage region.
// FIXME: If -faddress-sanitizer is enabled, insert dynamic instrumentation
// to check this.
llvm::Value *F = CGM.getIntrinsic(llvm::Intrinsic::objectsize, IntPtrTy);
llvm::Value *Min = Builder.getFalse();
llvm::Value *CastAddr = Builder.CreateBitCast(Address, Int8PtrTy);
llvm::Value *LargeEnough =
Builder.CreateICmpUGE(Builder.CreateCall2(F, Address, Min),
Builder.CreateICmpUGE(Builder.CreateCall2(F, CastAddr, Min),
llvm::ConstantInt::get(IntPtrTy, Size));
Cond = Cond ? Builder.CreateAnd(Cond, LargeEnough) : LargeEnough;
}

18
clang/test/CodeGen/catch-undef-behavior.c
View File

@ -21,14 +21,18 @@
// CHECK: @foo
void foo() {
union { int i; } u;
// CHECK: %[[SIZE:.*]] = call i64 @llvm.objectsize.i64({{.*}} %[[PTR:.*]], i1 false)
// CHECK-NEXT: %[[CHECK1:.*]] = icmp uge i64 %[[SIZE]], 4
// CHECK: %[[CHECK0:.*]] = icmp ne {{.*}}* %[[PTR:.*]], null
// CHECK: %[[PTRTOINT:.*]] = ptrtoint {{.*}} %[[PTR]] to i64
// CHECK: %[[I8PTR:.*]] = bitcast i32* %[[PTR]] to i8*
// CHECK-NEXT: %[[SIZE:.*]] = call i64 @llvm.objectsize.i64(i8* %[[I8PTR]], i1 false)
// CHECK-NEXT: %[[CHECK1:.*]] = icmp uge i64 %[[SIZE]], 4
// CHECK-NEXT: %[[CHECK01:.*]] = and i1 %[[CHECK0]], %[[CHECK1]]
// CHECK: %[[PTRTOINT:.*]] = ptrtoint {{.*}}* %[[PTR]] to i64
// CHECK-NEXT: %[[MISALIGN:.*]] = and i64 %[[PTRTOINT]], 3
// CHECK-NEXT: %[[CHECK2:.*]] = icmp eq i64 %[[MISALIGN]], 0
// CHECK: %[[OK:.*]] = and i1 %[[CHECK1]], %[[CHECK2]]
// CHECK: %[[OK:.*]] = and i1 %[[CHECK01]], %[[CHECK2]]
// CHECK-NEXT: br i1 %[[OK]]
// CHECK: %[[ARG:.*]] = ptrtoint {{.*}} %[[PTR]] to i64
@ -52,6 +56,12 @@ int bar(int *a) {
return *a;
}
// CHECK: @addr_space
int addr_space(int __attribute__((address_space(256))) *a) {
// CHECK-NOT: __ubsan
return *a;
}
// CHECK: @lsh_overflow
int lsh_overflow(int a, int b) {
// CHECK: %[[INBOUNDS:.*]] = icmp ule i32 %[[RHS:.*]], 31