[AIX]Generate debug info for static init related functions

[Xiangling_L]

Summary

Set the debug location for static init related functions(dtor and finalize) so we can generate valid debug info on AIX by invoking -g with clang or -debug-info-kind=limited with clang_cc1.

This also works for any other future targets who may use sinit and sterm functions for static initialization, where a direct call to dtor will be generated within finalize function body.

This patch also aims at validating that the debug info generated is correct for AIX sinit related functions.

[dblaikie]

clang/lib/CodeGen/CGDeclCXX.cpp

248–251

Any ideas why this is only showing up for AIX & not other targets, given this code looks to be generic, not AIX-specific?

clang/test/CodeGenCXX/aix-static-init-debug-info.cpp

10–20

This could probably be simplified to:

struct X {
  X();
  ~X();
};

This would still produce a global ctor and dtor without the superfluous variable, etc.

[hubert.reinterpretcast]

clang/lib/CodeGen/CGDeclCXX.cpp

248–251

Yes, because the AIX implementation generates a direct call to the stub function on the finalization path when it finds that a stub was still registered with atexit.

That would explain why other platforms to not encounter this message:

inlinable function call in a function with debug info must have a !dbg location

[dblaikie]

clang/lib/CodeGen/CGDeclCXX.cpp

248–251

Ah, fair enough - thanks for the context!

clang/test/CodeGenCXX/aix-static-init-debug-info.cpp

10–20

Could you simplify the test a bit like this? If it's only about the global /dtor/, perhaps omit the ctor in X too.

& which exact call in the test is the important one? Perhaps just test that?

[Xiangling_L]

Simplified the testcase;

[dblaikie]

Looks good - thanks!