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[tsan] Do not report errors in __destroy_helper_block_ 

There is a synchronization point between the reference count of a block dropping to zero and it's destruction, which TSan does not observe. Do not report errors in the compiler-emitted block destroy method and everything called from it.

This is similar to https://reviews.llvm.org/D25857

Differential Revision: https://reviews.llvm.org/D28387

llvm-svn: 291868
This commit is contained in:
Anna Zaks 2017-01-13 00:50:50 +00:00
parent dcfc191404
commit e43b4fc0ae
2 changed files with 22 additions and 7 deletions
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14
clang/lib/CodeGen/CodeGenFunction.cpp
View File

@ -708,6 +708,11 @@ static bool endsWithReturn(const Decl* F) {
return false;
}
static void markAsIgnoreThreadCheckingAtRuntime(llvm::Function *Fn) {
Fn->addFnAttr("sanitize_thread_no_checking_at_run_time");
Fn->removeFnAttr(llvm::Attribute::SanitizeThread);
}
void CodeGenFunction::StartFunction(GlobalDecl GD,
QualType RetTy,
llvm::Function *Fn,
@ -751,16 +756,19 @@ void CodeGenFunction::StartFunction(GlobalDecl GD,
Fn->addFnAttr(llvm::Attribute::SafeStack);
// Ignore TSan memory acesses from within ObjC/ObjC++ dealloc, initialize,
// .cxx_destruct and all of their calees at run time.
// .cxx_destruct, __destroy_helper_block_ and all of their calees at run time.
if (SanOpts.has(SanitizerKind::Thread)) {
if (const auto *OMD = dyn_cast_or_null<ObjCMethodDecl>(D)) {
IdentifierInfo *II = OMD->getSelector().getIdentifierInfoForSlot(0);
if (OMD->getMethodFamily() == OMF_dealloc ||
OMD->getMethodFamily() == OMF_initialize ||
(OMD->getSelector().isUnarySelector() && II->isStr(".cxx_destruct"))) {
Fn->addFnAttr("sanitize_thread_no_checking_at_run_time");
Fn->removeFnAttr(llvm::Attribute::SanitizeThread);
markAsIgnoreThreadCheckingAtRuntime(Fn);
}
} else if (const auto *FD = dyn_cast_or_null<FunctionDecl>(D)) {
IdentifierInfo *II = FD->getIdentifier();
if (II && II->isStr("__destroy_helper_block_"))
markAsIgnoreThreadCheckingAtRuntime(Fn);
}
}

15
clang/test/CodeGen/sanitize-thread-no-checking-at-run-time.m
View File

@ -1,5 +1,7 @@
// RUN: %clang_cc1 -triple x86_64-apple-darwin -x objective-c++ -emit-llvm -o - %s | FileCheck -check-prefix=WITHOUT %s
// RUN: %clang_cc1 -triple x86_64-apple-darwin -x objective-c++ -emit-llvm -o - %s -fsanitize=thread | FileCheck -check-prefix=TSAN %s
// RUN: %clang_cc1 -triple x86_64-apple-darwin -x objective-c++ -fblocks -emit-llvm -o - %s | FileCheck -check-prefix=WITHOUT %s
// RUN: %clang_cc1 -triple x86_64-apple-darwin -x objective-c++ -fblocks -emit-llvm -o - %s -fsanitize=thread | FileCheck -check-prefix=TSAN %s
// WITHOUT-NOT: "sanitize_thread_no_checking_at_run_time"
__attribute__((objc_root_class))
@interface NSObject
@ -26,9 +28,14 @@ public:
}
@end
// WITHOUT-NOT: "sanitize_thread_no_checking_at_run_time"
// TSAN: initialize{{.*}}) [[ATTR:#[0-9]+]]
// TSAN: dealloc{{.*}}) [[ATTR:#[0-9]+]]
// TSAN: cxx_destruct{{.*}}) [[ATTR:#[0-9]+]]
void test2(id x) {
extern void test2_helper(id (^)(void));
test2_helper(^{ return x; });
// TSAN: define internal void @__destroy_helper_block_(i8*) [[ATTR:#[0-9]+]]
}
// TSAN: attributes [[ATTR]] = { noinline nounwind {{.*}} "sanitize_thread_no_checking_at_run_time" {{.*}} }