FindUsedTypes.cpp revision c287137ce7455c63be0075e0d5aba0bab4f125ea 
1//===- FindUsedTypes.cpp - Find all Types used by a module ----------------===//
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 pass is used to seek out all of the types in use by the program.  Note
11// that this analysis explicitly does not include types only used by the symbol
12// table.
13//
14//===----------------------------------------------------------------------===//
15
16#include "llvm/Analysis/FindUsedTypes.h"
17#include "llvm/Constants.h"
18#include "llvm/DerivedTypes.h"
19#include "llvm/Module.h"
20#include "llvm/Assembly/Writer.h"
21#include "llvm/Support/InstIterator.h"
22#include "llvm/Support/raw_ostream.h"
23using namespace llvm;
24
25char FindUsedTypes::ID = 0;
26static RegisterPass<FindUsedTypes>
27X("print-used-types", "Find Used Types", false, true);
28
29// IncorporateType - Incorporate one type and all of its subtypes into the
30// collection of used types.
31//
32void FindUsedTypes::IncorporateType(const Type *Ty) {
33  // If ty doesn't already exist in the used types map, add it now, otherwise
34  // return.
35  if (!UsedTypes.insert(Ty).second) return;  // Already contain Ty.
36
37  // Make sure to add any types this type references now.
38  //
39  for (Type::subtype_iterator I = Ty->subtype_begin(), E = Ty->subtype_end();
40       I != E; ++I)
41    IncorporateType(*I);
42}
43
44void FindUsedTypes::IncorporateValue(const Value *V) {
45  IncorporateType(V->getType());
46
47  // If this is a constant, it could be using other types...
48  if (const Constant *C = dyn_cast<Constant>(V)) {
49    if (!isa<GlobalValue>(C))
50      for (User::const_op_iterator OI = C->op_begin(), OE = C->op_end();
51           OI != OE; ++OI)
52        IncorporateValue(*OI);
53  }
54}
55
56
57// run - This incorporates all types used by the specified module
58//
59bool FindUsedTypes::runOnModule(Module &m) {
60  UsedTypes.clear();  // reset if run multiple times...
61
62  // Loop over global variables, incorporating their types
63  for (Module::const_global_iterator I = m.global_begin(), E = m.global_end();
64       I != E; ++I) {
65    IncorporateType(I->getType());
66    if (I->hasInitializer())
67      IncorporateValue(I->getInitializer());
68  }
69
70  for (Module::iterator MI = m.begin(), ME = m.end(); MI != ME; ++MI) {
71    IncorporateType(MI->getType());
72    const Function &F = *MI;
73
74    // Loop over all of the instructions in the function, adding their return
75    // type as well as the types of their operands.
76    //
77    for (const_inst_iterator II = inst_begin(F), IE = inst_end(F);
78         II != IE; ++II) {
79      const Instruction &I = *II;
80
81      IncorporateType(I.getType());  // Incorporate the type of the instruction
82      for (User::const_op_iterator OI = I.op_begin(), OE = I.op_end();
83           OI != OE; ++OI)
84        IncorporateValue(*OI);  // Insert inst operand types as well
85    }
86  }
87
88  return false;
89}
90
91// Print the types found in the module.  If the optional Module parameter is
92// passed in, then the types are printed symbolically if possible, using the
93// symbol table from the module.
94//
95void FindUsedTypes::print(std::ostream &OS, const Module *M) const {
96  raw_os_ostream RO(OS);
97  RO << "Types in use by this module:\n";
98  for (std::set<const Type *>::const_iterator I = UsedTypes.begin(),
99       E = UsedTypes.end(); I != E; ++I) {
100    RO << "   ";
101    WriteTypeSymbolic(RO, *I, M);
102    RO << '\n';
103  }
104}
105