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FindUsedTypes.cpp

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00001 //===- FindUsedTypes.cpp - Find all Types used by a module ----------------===//
00002 // 
00003 //                     The LLVM Compiler Infrastructure
00004 //
00005 // This file was developed by the LLVM research group and is distributed under
00006 // the University of Illinois Open Source License. See LICENSE.TXT for details.
00007 // 
00008 //===----------------------------------------------------------------------===//
00009 //
00010 // This pass is used to seek out all of the types in use by the program.  Note
00011 // that this analysis explicitly does not include types only used by the symbol
00012 // table.
00013 //
00014 //===----------------------------------------------------------------------===//
00015 
00016 #include "llvm/Analysis/FindUsedTypes.h"
00017 #include "llvm/Constants.h"
00018 #include "llvm/DerivedTypes.h"
00019 #include "llvm/Module.h"
00020 #include "llvm/SymbolTable.h"
00021 #include "llvm/Assembly/CachedWriter.h"
00022 #include "llvm/Support/InstIterator.h"
00023 using namespace llvm;
00024 
00025 static RegisterAnalysis<FindUsedTypes>
00026 X("printusedtypes", "Find Used Types");
00027 
00028 // stub to help linkage
00029 void FindUsedTypes::stub() {}
00030 
00031 // IncorporateType - Incorporate one type and all of its subtypes into the
00032 // collection of used types.
00033 //
00034 void FindUsedTypes::IncorporateType(const Type *Ty) {
00035   // If ty doesn't already exist in the used types map, add it now, otherwise 
00036   // return.
00037   if (!UsedTypes.insert(Ty).second) return;  // Already contain Ty.
00038                              
00039   // Make sure to add any types this type references now.
00040   //
00041   for (Type::subtype_iterator I = Ty->subtype_begin(), E = Ty->subtype_end();
00042        I != E; ++I)
00043     IncorporateType(*I);
00044 }
00045 
00046 void FindUsedTypes::IncorporateValue(const Value *V) {
00047   IncorporateType(V->getType());
00048   
00049   // If this is a constant, it could be using other types...
00050   if (const Constant *C = dyn_cast<Constant>(V)) {
00051     if (!isa<GlobalValue>(C))
00052       for (User::const_op_iterator OI = C->op_begin(), OE = C->op_end();
00053      OI != OE; ++OI)
00054   IncorporateValue(*OI);
00055   }
00056 }
00057 
00058 
00059 // run - This incorporates all types used by the specified module
00060 //
00061 bool FindUsedTypes::runOnModule(Module &m) {
00062   UsedTypes.clear();  // reset if run multiple times...
00063 
00064   // Loop over global variables, incorporating their types
00065   for (Module::const_giterator I = m.gbegin(), E = m.gend(); I != E; ++I) {
00066     IncorporateType(I->getType());
00067     if (I->hasInitializer())
00068       IncorporateValue(I->getInitializer());
00069   }
00070 
00071   for (Module::iterator MI = m.begin(), ME = m.end(); MI != ME; ++MI) {
00072     IncorporateType(MI->getType());
00073     const Function &F = *MI;
00074   
00075     // Loop over all of the instructions in the function, adding their return
00076     // type as well as the types of their operands.
00077     //
00078     for (const_inst_iterator II = inst_begin(F), IE = inst_end(F);
00079          II != IE; ++II) {
00080       const Instruction &I = *II;
00081     
00082       IncorporateType(I.getType());  // Incorporate the type of the instruction
00083       for (User::const_op_iterator OI = I.op_begin(), OE = I.op_end();
00084            OI != OE; ++OI)
00085         IncorporateValue(*OI);  // Insert inst operand types as well
00086     }
00087   }
00088  
00089   return false;
00090 }
00091 
00092 // Print the types found in the module.  If the optional Module parameter is
00093 // passed in, then the types are printed symbolically if possible, using the
00094 // symbol table from the module.
00095 //
00096 void FindUsedTypes::print(std::ostream &o, const Module *M) const {
00097   o << "Types in use by this module:\n";
00098   if (M) {
00099     CachedWriter CW(M, o);
00100     for (std::set<const Type *>::const_iterator I = UsedTypes.begin(),
00101            E = UsedTypes.end(); I != E; ++I)
00102       CW << "  " << **I << "\n";
00103   } else
00104     for (std::set<const Type *>::const_iterator I = UsedTypes.begin(),
00105            E = UsedTypes.end(); I != E; ++I)
00106       o << "  " << **I << "\n";
00107 }