[PATCH] D115417: [LTO] Fix incomplete optimization remarks when PreOptModuleHook or PostInternalizeModuleHook is defined

[Xu Mingjie via Phabricator via llvm-commits]

Enna1 added a comment.

In https://reviews.llvm.org/D46376, we add support for optimization remarks to ThinLTO Backend, we call `finalizeOptimizationRemarks()` when PreOptModuleHook, PostPromoteModuleHook, PostInternalizeModuleHook, PostImportModuleHook is defined.

This patch call `finalizeOptimizationRemarks()` when PreOptModuleHook or PostInternalizeModuleHook is defined for Regular LTO Backend.

Cause `llvm-lto2` does not have an option to define PreOptModuleHook or PreOptModuleHook for Regular LTO Backend, it's hard to write a testcase.

We can reproduce this bug using the following testcase:

$ clang++ -c -flto tu1.cpp -o tu1.o
$ clang++ -c -flto tu2.cpp -o tu2.o
$ clang++ -fuse-ld=lld -flto -foptimization-record-passes=lto tu1.o tu2.o -Wl,--opt-remarks-filename,opt.lto.yaml -Wl,--plugin-opt=emit-llvm

The content of tu1.cpp and tu2.cpp:

  // tu1.cpp
  int unused(int a);
  int probably_inlined(int a);
  int main(int argc, const char *argv[]) {
    return probably_inlined(argc);
  }
  // tu2.cpp
  int unused(int a) {
    return a + 1;
  }
  int probably_inlined(int a) {
    return a + 2;
  }

The content of `opt.lto.yaml` is empty or incomplete due to this bug.

If this patch is applied, the content of `opt.lto.yaml` will be:

  --- !Passed
  Pass:            lto
  Name:            deadfunction
  Function:        _Z6unusedi
  Args:
    - Function:        _Z6unusedi
    - String:          ' not added to the combined module '
  ...


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D115417/new/

https://reviews.llvm.org/D115417