[all-commits] [llvm/llvm-project] 1fcc2b: Reapply "[DebugInfo] Alternate (more efficient) MD...

[Paul T Robinson via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 1fcc2bc31bb9352a13445ff4a5cccb0bebb8ea5b
      https://github.com/llvm/llvm-project/commit/1fcc2bc31bb9352a13445ff4a5cccb0bebb8ea5b
  Author: Paul Robinson <paul.robinson at sony.com>
  Date:   2023-08-18 (Fri, 18 Aug 2023)

  Changed paths:
    M clang/lib/CodeGen/CGDebugInfo.cpp
    M clang/lib/CodeGen/CGDebugInfo.h
    M clang/test/CodeGenCXX/debug-info-function-context.cpp

  Log Message:
  -----------
  Reapply "[DebugInfo] Alternate (more efficient) MD5 fix"

D155991 changed the file lookup to do a full string compare on the
filename; however, this added ~0.5% to compile time with -g.
Go back to the previous pointer-based lookup, but capture the main
file's checksum as well as its name to use when creating the extra
DIFile entry. This causes all entries to be consistent and also
avoids computing the checksum twice.

This reverts commit 5956648fc3ba11dd6b0d0f2d1d9b923e7f80f247.
There was a string lifetime issue that is now corrected.

Differential Revision: https://reviews.llvm.org/D156571