[all-commits] [llvm/llvm-project] b12a74: [Clang][AST] Fix a crash on attaching doc comments...

[Shanzhi via All-commits]

  Branch: refs/heads/release/18.x
  Home:   https://github.com/llvm/llvm-project
  Commit: b12a742c20ae548c5d84f1719f9199577b382ccd
      https://github.com/llvm/llvm-project/commit/b12a742c20ae548c5d84f1719f9199577b382ccd
  Author: Shanzhi <chenshanzhi at huawei.com>
  Date:   2024-02-08 (Thu, 08 Feb 2024)

  Changed paths:
    M clang/lib/AST/ASTContext.cpp
    A clang/test/AST/ast-crash-doc-function-template.cpp

  Log Message:
  -----------
  [Clang][AST] Fix a crash on attaching doc comments (#78716)

This crash is basically caused by calling
`ASTContext::getRawCommentForDeclNoCacheImp` with its input arguments
`RepresentativeLocForDecl` and `CommentsInTheFile` refering to different
files. A reduced reproducer is provided in this patch.

After the source locations for instantiations of funtion template are
corrected in the commit 256a0b298c68b89688b80350b034daf2f7785b67, the
variable `CommitsInThisFile` in the function
`ASTContext::attachCommentsToJustParsedDecls` would refer to the source
file rather than the header file for implicit function template
instantiation. Therefore, in the first loop in
`ASTContext::attachCommentsToJustParsedDecls`, `D` should also be
adjusted for relevant scenarios like the second loop.

Fixes #67979
Fixes #68524
Fixes #70550

(cherry picked from commit 5f4ee5a2dfa97fe32ee62d1d67aa1413d5a059e6)