contrib/llvm/lib/CodeGen/CountingFunctionInserter.cpp

   1 //===- CountingFunctionInserter.cpp - Insert mcount-like function calls ---===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9 //
  10 // Insert calls to counter functions, such as mcount, intended to be called
  11 // once per function, at the beginning of each function.
  12 //
  13 //===----------------------------------------------------------------------===//
  14
  15 #include "llvm/Analysis/GlobalsModRef.h"
  16 #include "llvm/CodeGen/Passes.h"
  17 #include "llvm/IR/Function.h"
  18 #include "llvm/IR/Instructions.h"
  19 #include "llvm/IR/Module.h"
  20 #include "llvm/IR/Type.h"
  21 #include "llvm/Pass.h"
  22 using namespace llvm;
  23
  24 namespace {
  25   struct CountingFunctionInserter : public FunctionPass {
  26     static char ID; // Pass identification, replacement for typeid
  27     CountingFunctionInserter() : FunctionPass(ID) {
  28       initializeCountingFunctionInserterPass(*PassRegistry::getPassRegistry());
  29     }
  30
  31     void getAnalysisUsage(AnalysisUsage &AU) const override {
  32       AU.addPreserved<GlobalsAAWrapperPass>();
  33     }
  34
  35     bool runOnFunction(Function &F) override {
  36       std::string CountingFunctionName =
  37         F.getFnAttribute("counting-function").getValueAsString();
  38       if (CountingFunctionName.empty())
  39         return false;
  40
  41       Type *VoidTy = Type::getVoidTy(F.getContext());
  42       Constant *CountingFn =
  43         F.getParent()->getOrInsertFunction(CountingFunctionName,
  44                                            VoidTy);
  45       CallInst::Create(CountingFn, "", &*F.begin()->getFirstInsertionPt());
  46       return true;
  47     }
  48   };
  49
  50   char CountingFunctionInserter::ID = 0;
  51 }
  52
  53 INITIALIZE_PASS(CountingFunctionInserter, "cfinserter",
  54                 "Inserts calls to mcount-like functions", false, false)
  55
  56 //===----------------------------------------------------------------------===//
  57 //
  58 // CountingFunctionInserter - Give any unnamed non-void instructions "tmp" names.
  59 //
  60 FunctionPass *llvm::createCountingFunctionInserterPass() {
  61   return new CountingFunctionInserter();
  62 }