FindUsedTypes.cpp revision a5dcc4f7b2a65afbeec9008733f47e6beee24bde 
1//===- FindUsedTypes.cpp - Find all Types used by a module ----------------===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file was developed by the LLVM research group and is distributed under
6// the University of Illinois Open Source 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/SymbolTable.h"
21#include "llvm/Assembly/CachedWriter.h"
22#include "llvm/Support/InstIterator.h"
23using namespace llvm;
24
25static RegisterAnalysis<FindUsedTypes>
26X("printusedtypes", "Find Used Types");
27
28// stub to help linkage
29void FindUsedTypes::stub() {}
30
31// IncorporateType - Incorporate one type and all of its subtypes into the
32// collection of used types.
33//
34void FindUsedTypes::IncorporateType(const Type *Ty) {
35  // If ty doesn't already exist in the used types map, add it now, otherwise
36  // return.
37  if (!UsedTypes.insert(Ty).second) return;  // Already contain Ty.
38
39  // Make sure to add any types this type references now.
40  //
41  for (Type::subtype_iterator I = Ty->subtype_begin(), E = Ty->subtype_end();
42       I != E; ++I)
43    IncorporateType(*I);
44}
45
46void FindUsedTypes::IncorporateValue(const Value *V) {
47  IncorporateType(V->getType());
48
49  // If this is a constant, it could be using other types...
50  if (const Constant *C = dyn_cast<Constant>(V)) {
51    for (User::const_op_iterator OI = C->op_begin(), OE = C->op_end();
52         OI != OE; ++OI)
53      IncorporateValue(*OI);
54  }
55}
56
57
58// run - This incorporates all types used by the specified module
59//
60bool FindUsedTypes::run(Module &m) {
61  UsedTypes.clear();  // reset if run multiple times...
62
63  // Loop over global variables, incorporating their types
64  for (Module::const_giterator I = m.gbegin(), E = m.gend(); 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 &o, const Module *M) const {
96  o << "Types in use by this module:\n";
97  if (M) {
98    CachedWriter CW(M, o);
99    for (std::set<const Type *>::const_iterator I = UsedTypes.begin(),
100           E = UsedTypes.end(); I != E; ++I)
101      CW << "  " << *I << "\n";
102  } else
103    for (std::set<const Type *>::const_iterator I = UsedTypes.begin(),
104           E = UsedTypes.end(); I != E; ++I)
105      o << "  " << *I << "\n";
106}
107