[clang] [llvm] wip: Move instrumentation passes (PR #92171)

[Arthur Eubanks via llvm-commits]

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@@ -1016,6 +1000,11 @@ void EmitAssemblyHelper::RunOptimizationPipeline(
     if (!IsThinLTOPostLink) {
       addSanitizers(TargetTriple, CodeGenOpts, LangOpts, PB);
       addKCFIPass(TargetTriple, LangOpts, PB);
+      PB.registerPipelineStartEPCallback(
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aeubanks wrote:

we should be consistent and make both entry exit instrumenters part of the default pipelines, not a clang-specific add-on

this would probably be somewhere in `buildModuleSimplificationPipeline`, checking `Phase` (and make sure -O0 works by modifying `buildO0DefaultPipeline`)

https://github.com/llvm/llvm-project/pull/92171