[llvm] [PGO] Instrument modules with at least a single function definition (PR #93421)

[Mingming Liu via llvm-commits]

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+; RUN: opt < %s -passes=pgo-instr-gen -S | FileCheck %s --implicit-check-not='__llvm_profile_raw_version'
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minglotus-6 wrote:

With all above said, I _think_ it's possible for a module to have global variables (say `file.cc` defines a list of constants, if `file.h` is not suitable), but not that common for a module to have vtable definitions only.

https://github.com/llvm/llvm-project/pull/93421