FindUsedTypes.cpp revision d0fde30ce850b78371fd1386338350591f9ff494 
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"
23
24namespace llvm {
25
26static RegisterAnalysis<FindUsedTypes>
27X("printusedtypes", "Find Used Types");
28
29// stub to help linkage
30void FindUsedTypes::stub() {}
31
32// IncorporateType - Incorporate one type and all of its subtypes into the
33// collection of used types.
34//
35void FindUsedTypes::IncorporateType(const Type *Ty) {
36  if (UsedTypes.count(Ty)) return;  // Already contain Ty.
37
38  // If ty doesn't already exist in the used types map, add it now.
39  //
40  UsedTypes.insert(Ty);
41
42  // Make sure to add any types this type references now.
43  //
44  for (Type::subtype_iterator I = Ty->subtype_begin(), E = Ty->subtype_end();
45       I != E; ++I)
46    IncorporateType(*I);
47}
48
49void FindUsedTypes::IncorporateValue(const Value *V) {
50  IncorporateType(V->getType());
51
52  // If this is a constant, it could be using other types...
53  if (const Constant *C = dyn_cast<Constant>(V)) {
54    for (User::const_op_iterator OI = C->op_begin(), OE = C->op_end();
55         OI != OE; ++OI)
56      IncorporateValue(*OI);
57  }
58}
59
60
61// run - This incorporates all types used by the specified module
62//
63bool FindUsedTypes::run(Module &m) {
64  UsedTypes.clear();  // reset if run multiple times...
65
66  // Loop over global variables, incorporating their types
67  for (Module::const_giterator I = m.gbegin(), E = m.gend(); I != E; ++I) {
68    IncorporateType(I->getType());
69    if (I->hasInitializer())
70      IncorporateValue(I->getInitializer());
71  }
72
73  for (Module::iterator MI = m.begin(), ME = m.end(); MI != ME; ++MI) {
74    IncorporateType(MI->getType());
75    const Function &F = *MI;
76
77    // Loop over all of the instructions in the function, adding their return
78    // type as well as the types of their operands.
79    //
80    for (const_inst_iterator II = inst_begin(F), IE = inst_end(F);
81         II != IE; ++II) {
82      const Instruction *I = *II;
83      const Type *Ty = I->getType();
84
85      IncorporateType(Ty);  // Incorporate the type of the instruction
86      for (User::const_op_iterator OI = I->op_begin(), OE = I->op_end();
87           OI != OE; ++OI)
88        IncorporateValue(*OI);  // Insert inst operand types as well
89    }
90  }
91
92  return false;
93}
94
95// Print the types found in the module.  If the optional Module parameter is
96// passed in, then the types are printed symbolically if possible, using the
97// symbol table from the module.
98//
99void FindUsedTypes::print(std::ostream &o, const Module *M) const {
100  o << "Types in use by this module:\n";
101  if (M) {
102    CachedWriter CW(M, o);
103    for (std::set<const Type *>::const_iterator I = UsedTypes.begin(),
104           E = UsedTypes.end(); I != E; ++I)
105      CW << "  " << *I << "\n";
106  } else
107    for (std::set<const Type *>::const_iterator I = UsedTypes.begin(),
108           E = UsedTypes.end(); I != E; ++I)
109      o << "  " << *I << "\n";
110}
111
112} // End llvm namespace
113