[PATCH] D126517: [Propeller] Promote functions with propeller profiles to .text.hot.

[Rahman Lavaee via Phabricator via llvm-commits]

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Today, text section prefixes (none, .unlikely, .hot, and .unkown) are determined based on PGO profile. However, Propeller may deem a function hot when PGO doesn't. Besides, when `-Wl,-keep-text-section-prefix=true` Propeller cannot enforce a global section ordering as the linker can only reorder sections within each output section (.text, .text.hot, .text.unlikely).

This patch promotes all functions with Propeller profiles (functions listed in the basic-block-sections profile) to .text.hot. The feature is hidden behind the flag `--bbsections-guided-section-prefix` which defaults to `true`.

The new implementation refactors the parsing of basic block sections profile into a new `BasicBlockSectionsProfileReader` analysis pass. This allows us to use the information earlier in `CodeGenPrepare` in order to set the functions text prefix. `BasicBlockSectionsProfileReader` will be used both by `BasicBlockSections` pass and `CodeGenPrepare`.

Fix amdgpu test. Originally reviewed in D122930 <https://reviews.llvm.org/D122930>.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D126517

Files:
  llvm/include/llvm/CodeGen/BasicBlockSectionsProfileReader.h
  llvm/include/llvm/CodeGen/Passes.h
  llvm/include/llvm/InitializePasses.h
  llvm/lib/CodeGen/BasicBlockSections.cpp
  llvm/lib/CodeGen/BasicBlockSectionsProfileReader.cpp
  llvm/lib/CodeGen/CMakeLists.txt
  llvm/lib/CodeGen/CodeGenPrepare.cpp
  llvm/lib/CodeGen/TargetPassConfig.cpp
  llvm/test/CodeGen/AArch64/O3-pipeline.ll
  llvm/test/CodeGen/AMDGPU/llc-pipeline.ll
  llvm/test/CodeGen/PowerPC/O3-pipeline.ll
  llvm/test/CodeGen/RISCV/O3-pipeline.ll
  llvm/test/CodeGen/X86/basic-block-sections-cold.ll
  llvm/test/CodeGen/X86/basic-block-sections-list.ll
  llvm/test/CodeGen/X86/basic-block-sections-listbb.ll
  llvm/test/CodeGen/X86/basic-block-sections-source-drift.ll
  llvm/test/CodeGen/X86/opt-pipeline.ll

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