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 }
90