[PATCH] D147366: [MLGO] Change MBB Profile Dump from using MBB numbers to MBB IDs

[Aiden Grossman via Phabricator via llvm-commits]

aidengrossman created this revision.
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Currenty, setting the -mbb-profile-dump dumps a CSV file with blocks
inside an individual function identified by their MBB numbers. This
patch changes the MBBs to be identified by their ID which is set at MBB
creation and not changed afterwards, making it inherently stable
throughout the backend. This alleviates concerns with the MBB IDs
changing between the profile dump and what ends up in the final object
file. The MBBs inside the SHT_LLVM_BB_ADDR_MAP sections are also
identified using their MBB ID rather than number, so if we want to match
them up we need to identify the MBBs here by number.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D147366

Files:
  llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
  llvm/test/CodeGen/MLRegalloc/bb-profile-dump.ll


Index: llvm/test/CodeGen/MLRegalloc/bb-profile-dump.ll
===================================================================
--- llvm/test/CodeGen/MLRegalloc/bb-profile-dump.ll
+++ llvm/test/CodeGen/MLRegalloc/bb-profile-dump.ll
@@ -3,7 +3,7 @@
 ; Check that the basic block profile dump outputs data and in the correct
 ; format.
 ;
-; RUN: llc -mtriple=x86_64-linux-unknown -o /dev/null -mbb-profile-dump=- %s | FileCheck %s
+; RUN: llc -mtriple=x86_64-linux-unknown -o /dev/null -basic-block-sections=list -mbb-profile-dump=- %s | FileCheck %s
 
 ; bb profile dump is not supported on NVPTX
 ; UNSUPPORTED: target=nvptx{{.*}}
Index: llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
===================================================================
--- llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
+++ llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
@@ -1924,14 +1924,14 @@
 
   OutStreamer->addBlankLine();
 
-  // Output MBB numbers, function names, and frequencies if the flag to dump
+  // Output MBB ids, function names, and frequencies if the flag to dump
   // MBB profile information has been set
   if (MBBProfileDumpFileOutput) {
     MachineBlockFrequencyInfo &MBFI =
         getAnalysis<LazyMachineBlockFrequencyInfoPass>().getBFI();
     for (const auto &MBB : *MF) {
       *MBBProfileDumpFileOutput.get()
-          << MF->getName() << "," << MBB.getNumber() << ","
+          << MF->getName() << "," << MBB.getBBID() << ","
           << MBFI.getBlockFreqRelativeToEntryBlock(&MBB) << "\n";
     }
   }


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