Avoid displaying -Runsafe-buffer-usage-in-container remarks
When -Runsafe-buffer-usage is turned on, it also turns the
-Runsafe-buffer-usage-in-container warning on implicitly. These are
hard-coded warnings for the std::span constructor. Instead of using
this warning, we want to mark span constructors as UNSAFE_BUFFER_USAGE
and have the normal warning work.
We were just not filtering this warning at all, so it was being printed
in third-party code using std::span. But, rather than making
-Runsafe-buffer-usage-in-container filtered on file paths, we just
ignore it and drop it on the floor entirely, since we need a solution
that will work for base::span too.
See also https://github.com/llvm/llvm-project/issues/80482.
Before this change:
```
In file included from ../../third_party/flatbuffers/src/tests/test.cpp:31:
In file included from ../../third_party/flatbuffers/src/include/flatbuffers/flatbuffers.h:24:
In file included from ../../third_party/flatbuffers/src/include/flatbuffers/array.h:25:
../../third_party/flatbuffers/src/include/flatbuffers/vector.h:311:10: remark: the two-parameter std::span construction is unsafe as it can introduce mismatch between buffer size and the bound information [-Runsafe-buffer-usage-in-container]
311 | return span<U>(vec.data(), vec.size());
| ^
```
After this change, the file compiles without remarks.
Bug: 40284755, 41497066
Change-Id: Ie861a8f8d49a8c4a36393ccf864d8068e78cbcb5
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5352810
Reviewed-by: Hans Wennborg <[email protected]>
Commit-Queue: danakj <[email protected]>
Cr-Commit-Position: refs/heads/main@{#1270348}
diff --git a/tools/clang/plugins/UnsafeBuffersPlugin.cpp b/tools/clang/plugins/UnsafeBuffersPlugin.cpp
index d364f612..687f4565 100644
--- a/tools/clang/plugins/UnsafeBuffersPlugin.cpp
+++ b/tools/clang/plugins/UnsafeBuffersPlugin.cpp
@@ -80,6 +80,15 @@
return PassthroughDiagnostic(level, diag);
}
+ // The `-Runsafe-buffer-usage-in-container` warning gets enabled along with
+ // `-Runsafe-buffer-usage`, but it's a hardcoded warning about std::span
+ // constructor. We don't want to emit these, we instead want the span ctor
+ // (and our own base::span ctor) to be marked [[clang::unsafe_buffer_usage]]
+ // and have that work: https://github.com/llvm/llvm-project/issues/80482
+ if (diag_id == clang::diag::warn_unsafe_buffer_usage_in_container) {
+ return;
+ }
+
if (!(diag_id == clang::diag::warn_unsafe_buffer_variable ||
diag_id == clang::diag::warn_unsafe_buffer_operation ||
diag_id == clang::diag::note_unsafe_buffer_operation ||
