Dtor callback emitted when msan attribute not repressed for this function.

[nmusgrave]

Summary

In addition to checking compiler flags, the front-end also examines the attributes of the destructor definition to ensure that the SanitizeMemory attribute is attached.

[eugenis]

What happens if the attribute is used with the "= default" destructor?

lib/CodeGen/CGClass.cpp

1483

I think it would be cleaner to use CodegenFunction::SanOpts

test/CodeGenCXX/sanitize-dtor-callback.cpp

22 ↗

(On Diff #31250)

Maybe move this to a separate test file? This one gets cluttered; for example, tail call is a completely orthogonal issue and attribute test should not have to deal with it.

25 ↗

(On Diff #31250)

Remove {{^ }} to make the check stronger.

[nmusgrave]

• refactored test into new file, revised how function attribute examined

[eugenis]

test/CodeGenCXX/sanitize-dtor-callback.cpp

72 ↗

(On Diff #31263)

extra lines?

[nmusgrave]

• modified test to examine default dtor with and without attribute

[eugenis]

LGTM, but please remove the extra lines in sanitize-dtor-callback.cpp.

[nmusgrave]

• removed attribute check

lib/CodeGen/CGClass.cpp

void CodeGenFunction::EmitDestructorBody(FunctionArgList &Args) {
   // Jump out through the epilogue cleanups.
   DtorEpilogue.ForceCleanup();
 
   // Exit the try if applicable.
   if (isTryBody)
     ExitCXXTryStmt(*cast<CXXTryStmt>(Body), true);
 
   // Insert memory-poisoning instrumentation.
-  if (CGM.getCodeGenOpts().SanitizeMemoryUseAfterDtor)
+  if (CGM.getCodeGenOpts().SanitizeMemoryUseAfterDtor
+      && SanOpts.has(SanitizerKind::Memory))
     EmitDtorSanitizerCallback(*this, Dtor);
 }
 
 void CodeGenFunction::emitImplicitAssignmentOperatorBody(FunctionArgList &Args) {
   const CXXMethodDecl *AssignOp = cast<CXXMethodDecl>(CurGD.getDecl());
   const Stmt *RootS = AssignOp->getBody();
   assert(isa<CompoundStmt>(RootS) &&
          "Body of an implicit assignment operator should be compound stmt.");

test/CodeGenCXX/sanitize-dtor-fn-attribute.cpp

+// Test -fsanitize-memory-use-after-dtor
+// RUN: %clang_cc1 -fsanitize=memory -fsanitize-memory-use-after-dtor -std=c++11 -triple=x86_64-pc-linux -emit-llvm -o - %s | FileCheck %s
+// RUN: %clang_cc1 -DATTRIBUTE -fsanitize=memory -fsanitize-memory-use-after-dtor -std=c++11 -triple=x86_64-pc-linux -emit-llvm -o - %s | FileCheck %s --check-prefix=CHECK-ATTR
+
+template <class T> class Vector {
+ public:
+  ~Vector() {}
+};
+
+struct No_San {
+  Vector<int> v;
+  No_San() { }
+#ifdef ATTRIBUTE
+  __attribute__((no_sanitize_memory)) ~No_San() = default;
+#else
+  ~No_San() = default;
+#endif
+};
+
+int main() {
+  No_San *ns = new No_San();
+  ns->~No_San();
+  return 0;
+}
+
+// Repressing the sanitization attribute results in no msan
+// instrumentation of the destructor
+// CHECK: define {{.*}}No_SanD1Ev{{.*}} [[ATTRIBUTE:#[0-9]+]]
+// CHECK: call void {{.*}}No_SanD2Ev
+// CHECK: call void @__sanitizer_dtor_callback
+// CHECK: ret void
+
+// CHECK-ATTR: define {{.*}}No_SanD1Ev{{.*}} [[ATTRIBUTE:#[0-9]+]]
+// CHECK-ATTR: call void {{.*}}No_SanD2Ev
+// CHECK-ATTR-NOT: call void @__sanitizer_dtor_callback
+// CHECK-ATTR: ret void
+
+
+// CHECK: define {{.*}}No_SanD2Ev{{.*}} [[ATTRIBUTE:#[0-9]+]]
+// CHECK: call void {{.*}}Vector
+// CHECK: call void @__sanitizer_dtor_callback
+// CHECK: ret void
+
+// CHECK-ATTR: define {{.*}}No_SanD2Ev{{.*}} [[ATTRIBUTE:#[0-9]+]]
+// CHECK-ATTR: call void {{.*}}Vector
+// CHECK-ATTR-NOT: call void @__sanitizer_dtor_callback
+// CHECK-ATTR: ret void
+
+// When attribute is repressed, the destructor does not emit any tail calls
+// CHECK: attributes [[ATTRIBUTE]] = {{.*}} sanitize_memory
+// CHECK-ATTR-NOT: attributes [[ATTRIBUTE]] = {{.*}} sanitize_memory