tools/opt/AnalysisWrappers.cpp

   1 //===- AnalysisWrappers.cpp - Wrappers around non-pass analyses -----------===//
   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 // This file defines pass wrappers around LLVM analyses that don't make sense to
  11 // be passes.  It provides a nice standard pass interface to these classes so
  12 // that they can be printed out by analyze.
  13 //
  14 // These classes are separated out of analyze.cpp so that it is more clear which
  15 // code is the integral part of the analyze tool, and which part of the code is
  16 // just making it so more passes are available.
  17 //
  18 //===----------------------------------------------------------------------===//
  19
  20 #include "llvm/Analysis/CallGraph.h"
  21 #include "llvm/IR/CallSite.h"
  22 #include "llvm/IR/Module.h"
  23 #include "llvm/Pass.h"
  24 #include "llvm/Support/raw_ostream.h"
  25 using namespace llvm;
  26
  27 namespace {
  28   /// ExternalFunctionsPassedConstants - This pass prints out call sites to
  29   /// external functions that are called with constant arguments.  This can be
  30   /// useful when looking for standard library functions we should constant fold
  31   /// or handle in alias analyses.
  32   struct ExternalFunctionsPassedConstants : public ModulePass {
  33     static char ID; // Pass ID, replacement for typeid
  34     ExternalFunctionsPassedConstants() : ModulePass(ID) {}
  35     bool runOnModule(Module &M) override {
  36       for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I) {
  37         if (!I->isDeclaration()) continue;
  38
  39         bool PrintedFn = false;
  40         for (User *U : I->users()) {
  41           Instruction *UI = dyn_cast<Instruction>(U);
  42           if (!UI) continue;
  43
  44           CallSite CS(cast<Value>(UI));
  45           if (!CS) continue;
  46
  47           for (CallSite::arg_iterator AI = CS.arg_begin(),
  48                E = CS.arg_end(); AI != E; ++AI) {
  49             if (!isa<Constant>(*AI)) continue;
  50
  51             if (!PrintedFn) {
  52               errs() << "Function '" << I->getName() << "':\n";
  53               PrintedFn = true;
  54             }
  55             errs() << *UI;
  56             break;
  57           }
  58         }
  59       }
  60
  61       return false;
  62     }
  63
  64     void getAnalysisUsage(AnalysisUsage &AU) const override {
  65       AU.setPreservesAll();
  66     }
  67   };
  68 }
  69
  70 char ExternalFunctionsPassedConstants::ID = 0;
  71 static RegisterPass<ExternalFunctionsPassedConstants>
  72   P1("print-externalfnconstants",
  73      "Print external fn callsites passed constants");