[all-commits] [llvm/llvm-project] 826c93: [AST] Use explicit type erasure in TypeSourceInfo ...

[Arseny via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 826c93f96efd8e34781c12cfcc6e7284691f6e8c
      https://github.com/llvm/llvm-project/commit/826c93f96efd8e34781c12cfcc6e7284691f6e8c
  Author: Arseny <ar at cs.msu.ru>
  Date:   2023-10-21 (Sat, 21 Oct 2023)

  Changed paths:
    M clang/include/clang/AST/TypeLoc.h

  Log Message:
  -----------
  [AST] Use explicit type erasure in TypeSourceInfo constructor (#68435)

When this file is included in a project compiled with GCC 13 `-Werror`,
compilation fails with the following diagnostic:
<pre>
/usr/lib/llvm-17.0/include/clang/AST/TypeLoc.h: In constructor
'clang::TypeSourceInfo::TypeSourceInfo(clang::QualType, size_t)':
/usr/lib/llvm-17.0/include/clang/AST/TypeLoc.h:245:9: error: 'void*
memset(void*, int, size_t)' clearing an object of non-trivial type
'class clang::TypeSourceInfo'; use assignment instead
[-Werror=class-memaccess]
  245 |   memset(this + 1, 0, DataSize);
      |   ~~~~~~^~~~~~~~~~~~~~~~~~~~~~~

</pre>
To avoid this, we add an explicit type cast. The cast to `void*` makes
sense, since other member functions of `TypeSourceInfo` also treat the
buffer `(this + 1)` of length `DataSize` as opaque memory, and was
likely left out by mistake.

Fixes: 4498663f3de0 ("[AST] Initialized data after TypeSourceInfo")

I also suggest to apply this to release/17.x if possible.