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/Module.h"
  21 #include "llvm/Pass.h"
  22 #include "llvm/Support/CallSite.h"
  23 #include "llvm/Analysis/CallGraph.h"
  24 #include "llvm/Support/raw_ostream.h"
  25 #include <iostream>
  26 using namespace llvm;
  27
  28 namespace {
  29   /// ExternalFunctionsPassedConstants - This pass prints out call sites to
  30   /// external functions that are called with constant arguments.  This can be
  31   /// useful when looking for standard library functions we should constant fold
  32   /// or handle in alias analyses.
  33   struct ExternalFunctionsPassedConstants : public ModulePass {
  34     static char ID; // Pass ID, replacement for typeid
  35     ExternalFunctionsPassedConstants() : ModulePass(&ID) {}
  36     virtual bool runOnModule(Module &M) {
  37       for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I)
  38         if (I->isDeclaration()) {
  39           bool PrintedFn = false;
  40           for (Value::use_iterator UI = I->use_begin(), E = I->use_end();
  41                UI != E; ++UI)
  42             if (Instruction *User = dyn_cast<Instruction>(*UI)) {
  43               CallSite CS = CallSite::get(User);
  44               if (CS.getInstruction()) {
  45                 for (CallSite::arg_iterator AI = CS.arg_begin(),
  46                        E = CS.arg_end(); AI != E; ++AI)
  47                   if (isa<Constant>(*AI)) {
  48                     if (!PrintedFn) {
  49                       errs() << "Function '" << I->getName() << "':\n";
  50                       PrintedFn = true;
  51                     }
  52                     errs() << *User;
  53                     break;
  54                   }
  55               }
  56             }
  57         }
  58
  59       return false;
  60     }
  61
  62     virtual void getAnalysisUsage(AnalysisUsage &AU) const {
  63       AU.setPreservesAll();
  64     }
  65   };
  66
  67   char ExternalFunctionsPassedConstants::ID = 0;
  68   RegisterPass<ExternalFunctionsPassedConstants>
  69   P1("print-externalfnconstants",
  70      "Print external fn callsites passed constants");
  71
  72   struct CallGraphPrinter : public ModulePass {
  73     static char ID; // Pass ID, replacement for typeid
  74     CallGraphPrinter() : ModulePass(&ID) {}
  75
  76     virtual void getAnalysisUsage(AnalysisUsage &AU) const {
  77       AU.setPreservesAll();
  78       AU.addRequiredTransitive<CallGraph>();
  79     }
  80     virtual bool runOnModule(Module &M) {
  81       getAnalysis<CallGraph>().print(std::cerr, &M);
  82       return false;
  83     }
  84   };
  85
  86   char CallGraphPrinter::ID = 0;
  87   RegisterPass<CallGraphPrinter>
  88     P2("print-callgraph", "Print a call graph");
  89 }