llvm/lib/Transforms/Utils/InstructionNamer.cpp

   1 //===- InstructionNamer.cpp - Give anonymous instructions names -----------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 //
   9 // This is a little utility pass that gives instructions names, this is mostly
  10 // useful when diffing the effect of an optimization because deleting an
  11 // unnamed instruction can change all other instruction numbering, making the
  12 // diff very noisy.
  13 //
  14 //===----------------------------------------------------------------------===//
  15
  16 #include "llvm/Transforms/Utils/InstructionNamer.h"
  17 #include "llvm/IR/Function.h"
  18 #include "llvm/IR/PassManager.h"
  19 #include "llvm/IR/Type.h"
  20 #include "llvm/InitializePasses.h"
  21 #include "llvm/Pass.h"
  22 #include "llvm/Transforms/Utils.h"
  23
  24 using namespace llvm;
  25
  26 namespace {
  27 void nameInstructions(Function &F) {
  28   for (auto &Arg : F.args()) {
  29     if (!Arg.hasName())
  30       Arg.setName("arg");
  31   }
  32
  33   for (BasicBlock &BB : F) {
  34     if (!BB.hasName())
  35       BB.setName("bb");
  36
  37     for (Instruction &I : BB) {
  38       if (!I.hasName() && !I.getType()->isVoidTy())
  39         I.setName("i");
  40     }
  41   }
  42 }
  43
  44 struct InstNamer : public FunctionPass {
  45   static char ID; // Pass identification, replacement for typeid
  46   InstNamer() : FunctionPass(ID) {
  47     initializeInstNamerPass(*PassRegistry::getPassRegistry());
  48   }
  49
  50   void getAnalysisUsage(AnalysisUsage &Info) const override {
  51     Info.setPreservesAll();
  52   }
  53
  54   bool runOnFunction(Function &F) override {
  55     nameInstructions(F);
  56     return true;
  57   }
  58 };
  59
  60   char InstNamer::ID = 0;
  61   } // namespace
  62
  63 INITIALIZE_PASS(InstNamer, "instnamer",
  64                 "Assign names to anonymous instructions", false, false)
  65 char &llvm::InstructionNamerID = InstNamer::ID;
  66 //===----------------------------------------------------------------------===//
  67 //
  68 // InstructionNamer - Give any unnamed non-void instructions "tmp" names.
  69 //
  70 FunctionPass *llvm::createInstructionNamerPass() {
  71   return new InstNamer();
  72 }
  73
  74 PreservedAnalyses InstructionNamerPass::run(Function &F,
  75                                             FunctionAnalysisManager &FAM) {
  76   nameInstructions(F);
  77   return PreservedAnalyses::all();
  78 }