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/Analysis/ValueTracking.h"
  14 #include "llvm/IR/CallSite.h"
  15 #include "llvm/IR/DataLayout.h"
  16 #include "llvm/IR/InstIterator.h"
  17 #include "llvm/IR/LLVMContext.h"
  18 #include "llvm/IR/Module.h"
  19 #include "llvm/Support/ErrorHandling.h"
  20 #include "llvm/Support/raw_ostream.h"
  21 using namespace llvm;
  22
  23 namespace {
  24   struct MemDerefPrinter : public FunctionPass {
  25     SmallVector<Value *, 4> Vec;
  26
  27     static char ID; // Pass identification, replacement for typeid
  28     MemDerefPrinter() : FunctionPass(ID) {
  29       initializeMemDerefPrinterPass(*PassRegistry::getPassRegistry());
  30     }
  31     void getAnalysisUsage(AnalysisUsage &AU) const override {
  32       AU.setPreservesAll();
  33     }
  34     bool runOnFunction(Function &F) override;
  35     void print(raw_ostream &OS, const Module * = nullptr) const override;
  36     void releaseMemory() override {
  37       Vec.clear();
  38     }
  39   };
  40 }
  41
  42 char MemDerefPrinter::ID = 0;
  43 INITIALIZE_PASS_BEGIN(MemDerefPrinter, "print-memderefs",
  44                       "Memory Dereferenciblity of pointers in function", false, true)
  45 INITIALIZE_PASS_END(MemDerefPrinter, "print-memderefs",
  46                     "Memory Dereferenciblity of pointers in function", false, true)
  47
  48 FunctionPass *llvm::createMemDerefPrinter() {
  49   return new MemDerefPrinter();
  50 }
  51
  52 bool MemDerefPrinter::runOnFunction(Function &F) {
  53   const DataLayout &DL = F.getParent()->getDataLayout();
  54   for (auto &I: inst_range(F)) {
  55     if (LoadInst *LI = dyn_cast<LoadInst>(&I)) {
  56       Value *PO = LI->getPointerOperand();
  57       if (isDereferenceablePointer(PO, DL))
  58         Vec.push_back(PO);
  59     }
  60   }
  61   return false;
  62 }
  63
  64 void MemDerefPrinter::print(raw_ostream &OS, const Module *M) const {
  65   OS << "The following are dereferenceable:\n";
  66   for (auto &V: Vec) {
  67     V->print(OS);
  68     OS << "\n\n";
  69   }
  70 }