FindUsedTypes.cpp revision dedf2bd5a34dac25e4245f58bb902ced6b64edd9 
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    if (!isa<GlobalValue>(C))
52      for (User::const_op_iterator OI = C->op_begin(), OE = C->op_end();
53           OI != OE; ++OI)
54        IncorporateValue(*OI);
55  }
56}
57
58
59// run - This incorporates all types used by the specified module
60//
61bool FindUsedTypes::runOnModule(Module &m) {
62  UsedTypes.clear();  // reset if run multiple times...
63
64  // Loop over global variables, incorporating their types
65  for (Module::const_global_iterator I = m.global_begin(), E = m.global_end(); I != E; ++I) {
66    IncorporateType(I->getType());
67    if (I->hasInitializer())
68      IncorporateValue(I->getInitializer());
69  }
70
71  for (Module::iterator MI = m.begin(), ME = m.end(); MI != ME; ++MI) {
72    IncorporateType(MI->getType());
73    const Function &F = *MI;
74
75    // Loop over all of the instructions in the function, adding their return
76    // type as well as the types of their operands.
77    //
78    for (const_inst_iterator II = inst_begin(F), IE = inst_end(F);
79         II != IE; ++II) {
80      const Instruction &I = *II;
81
82      IncorporateType(I.getType());  // Incorporate the type of the instruction
83      for (User::const_op_iterator OI = I.op_begin(), OE = I.op_end();
84           OI != OE; ++OI)
85        IncorporateValue(*OI);  // Insert inst operand types as well
86    }
87  }
88
89  return false;
90}
91
92// Print the types found in the module.  If the optional Module parameter is
93// passed in, then the types are printed symbolically if possible, using the
94// symbol table from the module.
95//
96void FindUsedTypes::print(std::ostream &o, const Module *M) const {
97  o << "Types in use by this module:\n";
98  if (M) {
99    CachedWriter CW(M, o);
100    for (std::set<const Type *>::const_iterator I = UsedTypes.begin(),
101           E = UsedTypes.end(); I != E; ++I)
102      CW << "  " << **I << "\n";
103  } else
104    for (std::set<const Type *>::const_iterator I = UsedTypes.begin(),
105           E = UsedTypes.end(); I != E; ++I)
106      o << "  " << **I << "\n";
107}
108