[all-commits] [llvm/llvm-project] c7689f: [Clang] Fix memory leak due to TemplateArgumentLis...

[Andrew Browne via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: c7689fd552cdf2b37e804a59322bd0661ccdd3c5
      https://github.com/llvm/llvm-project/commit/c7689fd552cdf2b37e804a59322bd0661ccdd3c5
  Author: Andrew Browne <browneee at google.com>
  Date:   2022-06-08 (Wed, 08 Jun 2022)

  Changed paths:
    M clang-tools-extra/clangd/AST.cpp
    M clang/docs/ReleaseNotes.rst
    M clang/include/clang/AST/DeclTemplate.h
    M clang/include/clang/AST/TemplateBase.h
    M clang/lib/AST/ASTImporter.cpp
    M clang/lib/AST/DeclTemplate.cpp
    M clang/lib/AST/TemplateBase.cpp
    M clang/lib/Sema/SemaTemplateInstantiateDecl.cpp

  Log Message:
  -----------
  [Clang] Fix memory leak due to TemplateArgumentListInfo used in AST node.

It looks like the leak is rooted at the allocation here:
https://github.com/llvm/llvm-project/blob/1a155ee7de3b62a2fabee86fb470a1554fadc54d/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp#L3857

The VarTemplateSpecializationDecl is allocated using placement new which uses the AST structure for ownership: https://github.com/llvm/llvm-project/blob/1a155ee7de3b62a2fabee86fb470a1554fadc54d/clang/lib/AST/DeclBase.cpp#L99

The problem is the TemplateArgumentListInfo inside https://github.com/llvm/llvm-project/blob/1a155ee7de3b62a2fabee86fb470a1554fadc54d/clang/include/clang/AST/DeclTemplate.h#L2721
This object contains a vector which does not use placement new: https://github.com/llvm/llvm-project/blob/1a155ee7de3b62a2fabee86fb470a1554fadc54d/clang/include/clang/AST/TemplateBase.h#L564

Apparently ASTTemplateArgumentListInfo should be used instead https://github.com/llvm/llvm-project/blob/1a155ee7de3b62a2fabee86fb470a1554fadc54d/clang/include/clang/AST/TemplateBase.h#L575

https://reviews.llvm.org/D125802#3551305

Reviewed By: aaron.ballman

Differential Revision: https://reviews.llvm.org/D126944