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      1 //===- FindUsedTypes.cpp - Find all Types used by a module ----------------===//
      2 //
      3 //                     The LLVM Compiler Infrastructure
      4 //
      5 // This file is distributed under the University of Illinois Open Source
      6 // 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"
     22 #include "llvm/Support/raw_ostream.h"
     23 using namespace llvm;
     24 
     25 char FindUsedTypes::ID = 0;
     26 INITIALIZE_PASS(FindUsedTypes, "print-used-types",
     27                 "Find Used Types", false, true)
     28 
     29 // IncorporateType - Incorporate one type and all of its subtypes into the
     30 // collection of used types.
     31 //
     32 void FindUsedTypes::IncorporateType(Type *Ty) {
     33   // If ty doesn't already exist in the used types map, add it now, otherwise
     34   // return.
     35   if (!UsedTypes.insert(Ty)) return;  // Already contain Ty.
     36 
     37   // Make sure to add any types this type references now.
     38   //
     39   for (Type::subtype_iterator I = Ty->subtype_begin(), E = Ty->subtype_end();
     40        I != E; ++I)
     41     IncorporateType(*I);
     42 }
     43 
     44 void FindUsedTypes::IncorporateValue(const Value *V) {
     45   IncorporateType(V->getType());
     46 
     47   // If this is a constant, it could be using other types...
     48   if (const Constant *C = dyn_cast<Constant>(V)) {
     49     if (!isa<GlobalValue>(C))
     50       for (User::const_op_iterator OI = C->op_begin(), OE = C->op_end();
     51            OI != OE; ++OI)
     52         IncorporateValue(*OI);
     53   }
     54 }
     55 
     56 
     57 // run - This incorporates all types used by the specified module
     58 //
     59 bool FindUsedTypes::runOnModule(Module &m) {
     60   UsedTypes.clear();  // reset if run multiple times...
     61 
     62   // Loop over global variables, incorporating their types
     63   for (Module::const_global_iterator I = m.global_begin(), E = m.global_end();
     64        I != E; ++I) {
     65     IncorporateType(I->getType());
     66     if (I->hasInitializer())
     67       IncorporateValue(I->getInitializer());
     68   }
     69 
     70   for (Module::iterator MI = m.begin(), ME = m.end(); MI != ME; ++MI) {
     71     IncorporateType(MI->getType());
     72     const Function &F = *MI;
     73 
     74     // Loop over all of the instructions in the function, adding their return
     75     // type as well as the types of their operands.
     76     //
     77     for (const_inst_iterator II = inst_begin(F), IE = inst_end(F);
     78          II != IE; ++II) {
     79       const Instruction &I = *II;
     80 
     81       IncorporateType(I.getType());  // Incorporate the type of the instruction
     82       for (User::const_op_iterator OI = I.op_begin(), OE = I.op_end();
     83            OI != OE; ++OI)
     84         IncorporateValue(*OI);  // Insert inst operand types as well
     85     }
     86   }
     87 
     88   return false;
     89 }
     90 
     91 // Print the types found in the module.  If the optional Module parameter is
     92 // passed in, then the types are printed symbolically if possible, using the
     93 // symbol table from the module.
     94 //
     95 void FindUsedTypes::print(raw_ostream &OS, const Module *M) const {
     96   OS << "Types in use by this module:\n";
     97   for (SetVector<Type *>::const_iterator I = UsedTypes.begin(),
     98        E = UsedTypes.end(); I != E; ++I) {
     99     OS << "   " << **I << '\n';
    100   }
    101 }
    102