r350779 - In nothrow new-expressions, null-check the result if we're going to
Richard Smith via cfe-commits
cfe-commits at lists.llvm.org
Wed Jan 9 16:03:29 PST 2019
Author: rsmith
Date: Wed Jan 9 16:03:29 2019
New Revision: 350779
URL: http://llvm.org/viewvc/llvm-project?rev=350779&view=rev
Log:
In nothrow new-expressions, null-check the result if we're going to
apply sanitizers to it.
This avoids a sanitizer false positive that we are initializing a null
pointer.
Modified:
cfe/trunk/lib/CodeGen/CGExprCXX.cpp
cfe/trunk/test/CodeGenCXX/catch-undef-behavior.cpp
Modified: cfe/trunk/lib/CodeGen/CGExprCXX.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CGExprCXX.cpp?rev=350779&r1=350778&r2=350779&view=diff
==============================================================================
--- cfe/trunk/lib/CodeGen/CGExprCXX.cpp (original)
+++ cfe/trunk/lib/CodeGen/CGExprCXX.cpp Wed Jan 9 16:03:29 2019
@@ -1656,9 +1656,10 @@ llvm::Value *CodeGenFunction::EmitCXXNew
// Emit a null check on the allocation result if the allocation
// function is allowed to return null (because it has a non-throwing
// exception spec or is the reserved placement new) and we have an
- // interesting initializer.
+ // interesting initializer will be running sanitizers on the initialization.
bool nullCheck = E->shouldNullCheckAllocation() &&
- (!allocType.isPODType(getContext()) || E->hasInitializer());
+ (!allocType.isPODType(getContext()) || E->hasInitializer() ||
+ sanitizePerformTypeCheck());
llvm::BasicBlock *nullCheckBB = nullptr;
llvm::BasicBlock *contBB = nullptr;
Modified: cfe/trunk/test/CodeGenCXX/catch-undef-behavior.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGenCXX/catch-undef-behavior.cpp?rev=350779&r1=350778&r2=350779&view=diff
==============================================================================
--- cfe/trunk/test/CodeGenCXX/catch-undef-behavior.cpp (original)
+++ cfe/trunk/test/CodeGenCXX/catch-undef-behavior.cpp Wed Jan 9 16:03:29 2019
@@ -520,6 +520,49 @@ void upcast_to_vbase() {
}
}
+struct nothrow {};
+void *operator new[](__SIZE_TYPE__, nothrow) noexcept;
+
+namespace NothrowNew {
+ struct X { X(); };
+
+ // CHECK-LABEL: define{{.*}}nothrow_new_trivial
+ void *nothrow_new_trivial() {
+ // CHECK: %[[is_null:.*]] = icmp eq i8*{{.*}}, null
+ // CHECK: br i1 %[[is_null]], label %[[null:.*]], label %[[nonnull:.*]]
+
+ // CHECK: [[nonnull]]:
+ // CHECK: llvm.objectsize
+ // CHECK: br i1
+ //
+ // CHECK: call {{.*}}__ubsan_handle_type_mismatch
+ //
+ // CHECK: [[null]]:
+ // CHECK-NOT: {{ }}br{{ }}
+ // CHECK: ret
+ return new (nothrow{}) char[123456];
+ }
+
+ // CHECK-LABEL: define{{.*}}nothrow_new_nontrivial
+ void *nothrow_new_nontrivial() {
+ // CHECK: %[[is_null:.*]] = icmp eq i8*{{.*}}, null
+ // CHECK: br i1 %[[is_null]], label %[[null:.*]], label %[[nonnull:.*]]
+
+ // CHECK: [[nonnull]]:
+ // CHECK: llvm.objectsize
+ // CHECK: br i1
+ //
+ // CHECK: call {{.*}}__ubsan_handle_type_mismatch
+ //
+ // CHECK: call {{.*}}_ZN10NothrowNew1XC1Ev
+ //
+ // CHECK: [[null]]:
+ // CHECK-NOT: {{ }}br{{ }}
+ // CHECK: ret
+ return new (nothrow{}) X[123456];
+ }
+}
+
struct ThisAlign {
void this_align_lambda();
void this_align_lambda_2();
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