[PATCH] D97755: [IRSymTab] Set FB_used on llvm.compiler.used symbols

[Fangrui Song via Phabricator via cfe-commits]

MaskRay added inline comments.


================
Comment at: clang/test/CodeGen/thinlto-inline-asm2.c:10
+
+//--- a.c
+const char *ref() {
----------------
tejohnson wrote:
> Is this other file needed for the test?
This is test the limitation.

If we fix the tracking for inline asm references (this traverses instructions and I don't know whether it should be fixed):

without the reference, the `ff_h264_cabac_tables` will be internalized if we don't have a reference. The test ensures that such improvement can be detected.

`llvm.compiler.used` means the references are seen by the linker, and do not need to suppress internalization if the linker has full knowledge.


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Comment at: llvm/test/ThinLTO/X86/asm.ll:11
+; NM-NOT: {{.}}
+; NM:     ---------------- T ref
+; NM-NOT: {{.}}
----------------
tejohnson wrote:
> MaskRay wrote:
> > tejohnson wrote:
> > > What is the behavior here without this patch?
> > This is not changed. `ff_h264_cabac_tables` is not in the IR symbol table.
> Same question here - is this file needed to test the handling of the llvm.compiler.used in the other file?
See my answer above.


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D97755/new/

https://reviews.llvm.org/D97755