[PATCH] D67053: [LLD] [COFF] Resolve source locations for undefined references using dwarf

Sun Sep 1 22:52:07 PDT 2019

mstorsjo marked an inline comment as done.
mstorsjo added inline comments.

================
Comment at: test/COFF/undefined-symbol-dwarf.s:15
+# CHECK-NEXT: >>> referenced by {{.*}}.o:(myptr)
+
+	.text
----------------
MaskRay wrote:
> clang -S output is verbose. Many directives in this file are not significant and they should be deleted to improve readability. The relocations are not resolved. Does that cause any problem?
> clang -S output is verbose. Many directives in this file are not significant and they should be deleted to improve readability.

Yes, I guess I could trim out some. This is also built with -O0 to make sure the inline function ends up in a separate comdat (`.section .text$_ZN1A5afuncEv` below) to test that resolving references in different sections work, but I guess I could use some optimization with `-fno-inline` or something similar to keep them separate.

However, I'm a little weary of doing too much manual cleanups of it, if it would make the debug info mismatch the actual code. I'm not very proficient in DWARF so I don't know for sure exactly what needs to match what here, and which of the debug sections could be removed without breaking it.

> The relocations are not resolved. Does that cause any problem?

Um, what do you mean? The errors about undefined symbols? That's the whole point of the test; to have undefined references, that we try to resolve back to source line numbers using the debug info.

Repository:
  rLLD LLVM Linker

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  https://reviews.llvm.org/D67053/new/

https://reviews.llvm.org/D67053