FindUsedTypes.cpp revision 1997473cf72957d0e70322e2fe6fe2ab141c58a6 
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/Assembly/Writer.h"
21#include "llvm/Support/InstIterator.h"
22using namespace llvm;
23
24char FindUsedTypes::ID = 0;
25static RegisterPass<FindUsedTypes>
26X("printusedtypes", "Find Used Types");
27
28// IncorporateType - Incorporate one type and all of its subtypes into the
29// collection of used types.
30//
31void FindUsedTypes::IncorporateType(const Type *Ty) {
32  // If ty doesn't already exist in the used types map, add it now, otherwise
33  // return.
34  if (!UsedTypes.insert(Ty).second) return;  // Already contain Ty.
35
36  // Make sure to add any types this type references now.
37  //
38  for (Type::subtype_iterator I = Ty->subtype_begin(), E = Ty->subtype_end();
39       I != E; ++I)
40    IncorporateType(*I);
41}
42
43void FindUsedTypes::IncorporateValue(const Value *V) {
44  IncorporateType(V->getType());
45
46  // If this is a constant, it could be using other types...
47  if (const Constant *C = dyn_cast<Constant>(V)) {
48    if (!isa<GlobalValue>(C))
49      for (User::const_op_iterator OI = C->op_begin(), OE = C->op_end();
50           OI != OE; ++OI)
51        IncorporateValue(*OI);
52  }
53}
54
55
56// run - This incorporates all types used by the specified module
57//
58bool FindUsedTypes::runOnModule(Module &m) {
59  UsedTypes.clear();  // reset if run multiple times...
60
61  // Loop over global variables, incorporating their types
62  for (Module::const_global_iterator I = m.global_begin(), E = m.global_end(); I != E; ++I) {
63    IncorporateType(I->getType());
64    if (I->hasInitializer())
65      IncorporateValue(I->getInitializer());
66  }
67
68  for (Module::iterator MI = m.begin(), ME = m.end(); MI != ME; ++MI) {
69    IncorporateType(MI->getType());
70    const Function &F = *MI;
71
72    // Loop over all of the instructions in the function, adding their return
73    // type as well as the types of their operands.
74    //
75    for (const_inst_iterator II = inst_begin(F), IE = inst_end(F);
76         II != IE; ++II) {
77      const Instruction &I = *II;
78
79      IncorporateType(I.getType());  // Incorporate the type of the instruction
80      for (User::const_op_iterator OI = I.op_begin(), OE = I.op_end();
81           OI != OE; ++OI)
82        IncorporateValue(*OI);  // Insert inst operand types as well
83    }
84  }
85
86  return false;
87}
88
89// Print the types found in the module.  If the optional Module parameter is
90// passed in, then the types are printed symbolically if possible, using the
91// symbol table from the module.
92//
93void FindUsedTypes::print(std::ostream &o, const Module *M) const {
94  o << "Types in use by this module:\n";
95  for (std::set<const Type *>::const_iterator I = UsedTypes.begin(),
96       E = UsedTypes.end(); I != E; ++I)
97    WriteTypeSymbolic(o << "  ", *I, M) << "\n";
98}
99
100// Ensure that this file gets linked in when FindUsedTypes.h is used.
101DEFINING_FILE_FOR(FindUsedTypes)
102