lib/Analysis/MemDerefPrinter.cpp

   1 //===- MemDerefPrinter.cpp - Printer for isDereferenceablePointer ---------===//
   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 #include "llvm/Analysis/Passes.h"
  11 #include "llvm/ADT/SetVector.h"
  12 #include "llvm/Analysis/MemoryDependenceAnalysis.h"
  13 #include "llvm/IR/CallSite.h"
  14 #include "llvm/IR/DataLayout.h"
  15 #include "llvm/IR/InstIterator.h"
  16 #include "llvm/IR/LLVMContext.h"
  17 #include "llvm/IR/Module.h"
  18 #include "llvm/Support/ErrorHandling.h"
  19 #include "llvm/Support/raw_ostream.h"
  20 using namespace llvm;
  21
  22 namespace {
  23   struct MemDerefPrinter : public FunctionPass {
  24     SmallVector<Value *, 4> Vec;
  25
  26     static char ID; // Pass identifcation, replacement for typeid
  27     MemDerefPrinter() : FunctionPass(ID) {
  28       initializeMemDerefPrinterPass(*PassRegistry::getPassRegistry());
  29     }
  30     void getAnalysisUsage(AnalysisUsage &AU) const override {
  31       AU.setPreservesAll();
  32     }
  33     bool runOnFunction(Function &F) override;
  34     void print(raw_ostream &OS, const Module * = nullptr) const override;
  35     void releaseMemory() override {
  36       Vec.clear();
  37     }
  38   };
  39 }
  40
  41 char MemDerefPrinter::ID = 0;
  42 INITIALIZE_PASS_BEGIN(MemDerefPrinter, "print-memderefs",
  43                       "Memory Dereferenciblity of pointers in function", false, true)
  44 INITIALIZE_PASS_END(MemDerefPrinter, "print-memderefs",
  45                     "Memory Dereferenciblity of pointers in function", false, true)
  46
  47 FunctionPass *llvm::createMemDerefPrinter() {
  48   return new MemDerefPrinter();
  49 }
  50
  51 bool MemDerefPrinter::runOnFunction(Function &F) {
  52   const DataLayout &DL = F.getParent()->getDataLayout();
  53   for (auto &I: inst_range(F)) {
  54     if (LoadInst *LI = dyn_cast<LoadInst>(&I)) {
  55       Value *PO = LI->getPointerOperand();
  56       if (PO->isDereferenceablePointer(&DL))
  57         Vec.push_back(PO);
  58     }
  59   }
  60   return false;
  61 }
  62
  63 void MemDerefPrinter::print(raw_ostream &OS, const Module *M) const {
  64   OS << "The following are dereferenceable:\n";
  65   for (auto &V: Vec) {
  66     V->print(OS);
  67     OS << "\n\n";
  68   }
  69 }