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      1 //===-- TypeFinder.cpp - Implement the TypeFinder class -------------------===//
      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 file implements the TypeFinder class for the IR library.
     11 //
     12 //===----------------------------------------------------------------------===//
     13 
     14 #include "llvm/IR/TypeFinder.h"
     15 #include "llvm/ADT/SmallVector.h"
     16 #include "llvm/IR/BasicBlock.h"
     17 #include "llvm/IR/DerivedTypes.h"
     18 #include "llvm/IR/Function.h"
     19 #include "llvm/IR/Metadata.h"
     20 #include "llvm/IR/Module.h"
     21 using namespace llvm;
     22 
     23 void TypeFinder::run(const Module &M, bool onlyNamed) {
     24   OnlyNamed = onlyNamed;
     25 
     26   // Get types from global variables.
     27   for (Module::const_global_iterator I = M.global_begin(),
     28          E = M.global_end(); I != E; ++I) {
     29     incorporateType(I->getType());
     30     if (I->hasInitializer())
     31       incorporateValue(I->getInitializer());
     32   }
     33 
     34   // Get types from aliases.
     35   for (Module::const_alias_iterator I = M.alias_begin(),
     36          E = M.alias_end(); I != E; ++I) {
     37     incorporateType(I->getType());
     38     if (const Value *Aliasee = I->getAliasee())
     39       incorporateValue(Aliasee);
     40   }
     41 
     42   // Get types from functions.
     43   SmallVector<std::pair<unsigned, MDNode*>, 4> MDForInst;
     44   for (Module::const_iterator FI = M.begin(), E = M.end(); FI != E; ++FI) {
     45     incorporateType(FI->getType());
     46 
     47     // First incorporate the arguments.
     48     for (Function::const_arg_iterator AI = FI->arg_begin(),
     49            AE = FI->arg_end(); AI != AE; ++AI)
     50       incorporateValue(AI);
     51 
     52     for (Function::const_iterator BB = FI->begin(), E = FI->end();
     53          BB != E;++BB)
     54       for (BasicBlock::const_iterator II = BB->begin(),
     55              E = BB->end(); II != E; ++II) {
     56         const Instruction &I = *II;
     57 
     58         // Incorporate the type of the instruction.
     59         incorporateType(I.getType());
     60 
     61         // Incorporate non-instruction operand types. (We are incorporating all
     62         // instructions with this loop.)
     63         for (User::const_op_iterator OI = I.op_begin(), OE = I.op_end();
     64              OI != OE; ++OI)
     65           if (!isa<Instruction>(OI))
     66             incorporateValue(*OI);
     67 
     68         // Incorporate types hiding in metadata.
     69         I.getAllMetadataOtherThanDebugLoc(MDForInst);
     70         for (unsigned i = 0, e = MDForInst.size(); i != e; ++i)
     71           incorporateMDNode(MDForInst[i].second);
     72 
     73         MDForInst.clear();
     74       }
     75   }
     76 
     77   for (Module::const_named_metadata_iterator I = M.named_metadata_begin(),
     78          E = M.named_metadata_end(); I != E; ++I) {
     79     const NamedMDNode *NMD = I;
     80     for (unsigned i = 0, e = NMD->getNumOperands(); i != e; ++i)
     81       incorporateMDNode(NMD->getOperand(i));
     82   }
     83 }
     84 
     85 void TypeFinder::clear() {
     86   VisitedConstants.clear();
     87   VisitedTypes.clear();
     88   StructTypes.clear();
     89 }
     90 
     91 /// incorporateType - This method adds the type to the list of used structures
     92 /// if it's not in there already.
     93 void TypeFinder::incorporateType(Type *Ty) {
     94   // Check to see if we're already visited this type.
     95   if (!VisitedTypes.insert(Ty).second)
     96     return;
     97 
     98   // If this is a structure or opaque type, add a name for the type.
     99   if (StructType *STy = dyn_cast<StructType>(Ty))
    100     if (!OnlyNamed || STy->hasName())
    101       StructTypes.push_back(STy);
    102 
    103   // Recursively walk all contained types.
    104   for (Type::subtype_iterator I = Ty->subtype_begin(),
    105          E = Ty->subtype_end(); I != E; ++I)
    106     incorporateType(*I);
    107 }
    108 
    109 /// incorporateValue - This method is used to walk operand lists finding types
    110 /// hiding in constant expressions and other operands that won't be walked in
    111 /// other ways.  GlobalValues, basic blocks, instructions, and inst operands are
    112 /// all explicitly enumerated.
    113 void TypeFinder::incorporateValue(const Value *V) {
    114   if (const MDNode *M = dyn_cast<MDNode>(V))
    115     return incorporateMDNode(M);
    116 
    117   if (!isa<Constant>(V) || isa<GlobalValue>(V)) return;
    118 
    119   // Already visited?
    120   if (!VisitedConstants.insert(V).second)
    121     return;
    122 
    123   // Check this type.
    124   incorporateType(V->getType());
    125 
    126   // If this is an instruction, we incorporate it separately.
    127   if (isa<Instruction>(V))
    128     return;
    129 
    130   // Look in operands for types.
    131   const User *U = cast<User>(V);
    132   for (Constant::const_op_iterator I = U->op_begin(),
    133          E = U->op_end(); I != E;++I)
    134     incorporateValue(*I);
    135 }
    136 
    137 /// incorporateMDNode - This method is used to walk the operands of an MDNode to
    138 /// find types hiding within.
    139 void TypeFinder::incorporateMDNode(const MDNode *V) {
    140   // Already visited?
    141   if (!VisitedConstants.insert(V).second)
    142     return;
    143 
    144   // Look in operands for types.
    145   for (unsigned i = 0, e = V->getNumOperands(); i != e; ++i)
    146     if (Value *Op = V->getOperand(i))
    147       incorporateValue(Op);
    148 }
    149