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      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");
     74 
     75 namespace {
     76   struct CallGraphPrinter : public ModulePass {
     77     static char ID; // Pass ID, replacement for typeid
     78     CallGraphPrinter() : ModulePass(ID) {}
     79 
     80     void getAnalysisUsage(AnalysisUsage &AU) const override {
     81       AU.setPreservesAll();
     82       AU.addRequiredTransitive<CallGraphWrapperPass>();
     83     }
     84     bool runOnModule(Module &M) override {
     85       getAnalysis<CallGraphWrapperPass>().print(errs(), &M);
     86       return false;
     87     }
     88   };
     89 }
     90 
     91 char CallGraphPrinter::ID = 0;
     92 static RegisterPass<CallGraphPrinter>
     93   P2("print-callgraph", "Print a call graph");
     94