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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.

llvm-svn: 350779
This commit is contained in:
Richard Smith 2019-01-10 00:03:29 +00:00
parent 2eeade1814
commit 2f72a7521a
2 changed files with 46 additions and 2 deletions
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5
clang/lib/CodeGen/CGExprCXX.cpp
View File

@ -1656,9 +1656,10 @@ llvm::Value *CodeGenFunction::EmitCXXNewExpr(const CXXNewExpr *E) {
// 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;

43
clang/test/CodeGenCXX/catch-undef-behavior.cpp
View File

@ -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();