[PATCH] D101097: [Sema] Don't set BlockDecl's DoesNotEscape bit If the block is being passed to a function taking a reference parameter
John McCall via Phabricator via cfe-commits
cfe-commits at lists.llvm.org
Thu Apr 22 21:59:23 PDT 2021
rjmccall added inline comments.
================
Comment at: clang/lib/Sema/SemaExpr.cpp:5917
if (auto *BE = dyn_cast<BlockExpr>(Arg->IgnoreParenNoopCasts(Context)))
BE->getBlockDecl()->setDoesNotEscape();
----------------
We need to be checking that the parameter type is a block pointer type. A parameter of a type like `id` or `void*` does not have the enhanced semantics of `noescape` for blocks.
The inevitable weird C++ test case is:
```
struct NoescapeCtor {
NoescapeCtor(__attribute__((noescape)) void (^)());
};
struct EscapeCtor {
EscapeCtor(void (^)());
};
void helper1(NoescapeCtor a);
void test1() { helper1(^{}); } // <- should be noescape
void helper2(NoescapeCtor &&a);
void test2() { helper2(^{}); } // <- should be noescape
void helper3(__attribute__((noescape)) EscapeCtor &&a);
void test3() { helper3(^{}); } // <- should not be noescape
```
You should probably also test that calls to function templates behave according to the instantiated type of the parameter. I expect that that should just fall out from this implementation, which I think only triggers on non-dependent calls.
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D101097/new/
https://reviews.llvm.org/D101097
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