FindUsedTypes.cpp revision 5057b00fafa930756c10e033f1a4406de4b21f83 
1//===- FindUsedTypes.cpp - Find all Types used by a module ------------------=//
2//
3// This pass is used to seek out all of the types in use by the program.
4//
5//===----------------------------------------------------------------------===//
6
7#include "llvm/Analysis/FindUsedTypes.h"
8#include "llvm/Assembly/CachedWriter.h"
9#include "llvm/SymbolTable.h"
10#include "llvm/DerivedTypes.h"
11#include "llvm/Module.h"
12#include "llvm/Support/InstIterator.h"
13
14static RegisterAnalysis<FindUsedTypes>
15X("printusedtypes", "Find Used Types");
16
17// stub to help linkage
18void FindUsedTypes::stub() {}
19
20// IncorporateType - Incorporate one type and all of its subtypes into the
21// collection of used types.
22//
23void FindUsedTypes::IncorporateType(const Type *Ty) {
24  if (UsedTypes.count(Ty)) return;  // Already contain Ty.
25
26  // If ty doesn't already exist in the used types map, add it now.
27  //
28  UsedTypes.insert(Ty);
29
30  // Make sure to add any types this type references now.
31  //
32  for (Type::subtype_iterator I = Ty->subtype_begin(), E = Ty->subtype_end();
33       I != E; ++I)
34    IncorporateType(*I);
35}
36
37
38// run - This incorporates all types used by the specified module
39//
40bool FindUsedTypes::run(Module &m) {
41  UsedTypes.clear();  // reset if run multiple times...
42
43  // Loop over global variables, incorporating their types
44  for (Module::const_giterator I = m.gbegin(), E = m.gend(); I != E; ++I)
45    IncorporateType(I->getType());
46
47  for (Module::iterator MI = m.begin(), ME = m.end(); MI != ME; ++MI) {
48    const Function &F = *MI;
49
50    // Loop over all of the instructions in the function, adding their return
51    // type as well as the types of their operands.
52    //
53    for (const_inst_iterator II = inst_begin(F), IE = inst_end(F);
54         II != IE; ++II) {
55      const Instruction *I = *II;
56      const Type *Ty = I->getType();
57
58      IncorporateType(Ty);  // Incorporate the type of the instruction
59      for (User::const_op_iterator OI = I->op_begin(), OE = I->op_end();
60           OI != OE; ++OI)
61        if ((*OI)->getType() != Ty)         // Avoid set lookup in common case
62          IncorporateType((*OI)->getType());// Insert inst operand types as well
63    }
64  }
65
66  return false;
67}
68
69// Print the types found in the module.  If the optional Module parameter is
70// passed in, then the types are printed symbolically if possible, using the
71// symbol table from the module.
72//
73void FindUsedTypes::print(std::ostream &o, const Module *M) const {
74  o << "Types in use by this module:\n";
75  if (M) {
76    CachedWriter CW(M, o);
77    for (std::set<const Type *>::const_iterator I = UsedTypes.begin(),
78           E = UsedTypes.end(); I != E; ++I)
79      CW << "  " << *I << "\n";
80  } else
81    for (std::set<const Type *>::const_iterator I = UsedTypes.begin(),
82           E = UsedTypes.end(); I != E; ++I)
83      o << "  " << *I << "\n";
84}
85