[Blocks] Inherit sanitizer options from parent decl

[vsk]

Summary

There is no way to apply sanitizer suppressions to ObjC blocks. A
reasonable default is to have blocks inherit their parent's sanitizer
options.

rdar://32769634

[vsk]

Friendly ping.

[zaks.anna]

LGTM.

Thanks!

I was wondering if there are other places where this propagation needs to be added, for example, other calls to GenerateBlockFunction.

[vsk]

In D40668#949096, @zaks.anna wrote:

LGTM.

Thanks!

I was wondering if there are other places where this propagation needs to be added, for example, other calls to GenerateBlockFunction.

Thanks for the review :). Yes there is one other site which calls GenerateBlockFunction, but that is done in CodeGenModule, where there are no SanOpts to inherit *except* those from the CGM, which is already the default behavior. (You can apply suppressions to those by specifying "_block_invoke*" in your blacklist.) So I think this is all that's needed.

lib/CodeGen/CGBlocks.cpp

auto GenVoidPtrTy =
       IsOpenCL ? CGM.getOpenCLRuntime().getGenericVoidPointerType() : VoidPtrTy;
   LangAS GenVoidPtrAddr = IsOpenCL ? LangAS::opencl_generic : LangAS::Default;
   auto GenVoidPtrSize = CharUnits::fromQuantity(
       CGM.getTarget().getPointerWidth(
           CGM.getContext().getTargetAddressSpace(GenVoidPtrAddr)) /
       8);
   // Using the computed layout, generate the actual block function.
   bool isLambdaConv = blockInfo.getBlockDecl()->isConversionFromLambda();
-  auto *InvokeFn = CodeGenFunction(CGM, true).GenerateBlockFunction(
+  CodeGenFunction BlockCGF{CGM, true};
+  BlockCGF.SanOpts = SanOpts;
+  auto *InvokeFn = BlockCGF.GenerateBlockFunction(
       CurGD, blockInfo, LocalDeclMap, isLambdaConv, blockInfo.CanBeGlobal);
   if (InvokeF)
     *InvokeF = InvokeFn;
   auto *blockFn = llvm::ConstantExpr::getPointerCast(InvokeFn, GenVoidPtrTy);
 
   // If there is nothing to capture, we can emit this as a global block.
   if (blockInfo.CanBeGlobal)
     return CGM.getAddrOfGlobalBlockIfEmitted(blockInfo.BlockExpression);

test/CodeGenObjC/no-sanitize.m

-// RUN: %clang_cc1 %s -emit-llvm -fsanitize=address -o - | FileCheck %s
+// RUN: %clang_cc1 %s -emit-llvm -fsanitize=address -fblocks -o - | FileCheck %s
 
 @interface I0 @end
 @implementation I0
 // CHECK-NOT: sanitize_address
 - (void) im0: (int) a0 __attribute__((no_sanitize("address"))) {
+  int (^blockName)() = ^int() { return 0; };
 }
 @end