mirror of
https://github.com/c64scene-ar/llvm-6502.git
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5c377c524a
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@810 91177308-0d34-0410-b5e6-96231b3b80d8
289 lines
11 KiB
C++
289 lines
11 KiB
C++
//===- Linker.cpp - Module Linker Implementation --------------------------===//
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//
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// This file implements the LLVM module linker.
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//
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// Specifically, this:
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// - Merges global variables between the two modules
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// - Uninit + Uninit = Init, Init + Uninit = Init, Init + Init = Error if !=
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/Transforms/Linker.h"
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#include "llvm/Module.h"
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#include "llvm/Method.h"
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#include "llvm/GlobalVariable.h"
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#include "llvm/SymbolTable.h"
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#include "llvm/DerivedTypes.h"
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#include "llvm/iOther.h"
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// Error - Simple wrapper function to conditionally assign to E and return true.
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// This just makes error return conditions a little bit simpler...
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//
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static inline bool Error(string *E, string Message) {
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if (E) *E = Message;
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return true;
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}
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#include "llvm/Assembly/Writer.h" // TODO: REMOVE
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// RemapOperand - Use LocalMap and GlobalMap to convert references from one
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// module to another. This is somewhat sophisticated in that it can
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// automatically handle constant references correctly as well...
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//
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static Value *RemapOperand(Value *In, map<const Value*, Value*> &LocalMap,
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const map<const Value*, Value*> *GlobalMap = 0) {
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map<const Value*,Value*>::const_iterator I = LocalMap.find(In);
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if (I != LocalMap.end()) return I->second;
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if (GlobalMap) {
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I = GlobalMap->find(In);
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if (I != GlobalMap->end()) return I->second;
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}
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if (!isa<ConstPoolVal>(In))
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cerr << "Couldn't remap value: " << In << endl;
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return In;
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}
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// LinkGlobals - Loop through the global variables in the src module and merge
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// them into the dest module...
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//
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static bool LinkGlobals(Module *Dest, const Module *Src,
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map<const Value*, Value*> &ValueMap, string *Err = 0) {
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// We will need a module level symbol table if the src module has a module
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// level symbol table...
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SymbolTable *ST = Src->getSymbolTable() ? Dest->getSymbolTableSure() : 0;
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// Loop over all of the globals in the src module, mapping them over as we go
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//
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for (Module::const_giterator I = Src->gbegin(), E = Src->gend(); I != E; ++I){
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const GlobalVariable *GV = *I;
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Value *V;
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// If the global variable has a name, and that name is already in use in the
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// Dest module, make sure that the name is a compatible global variable...
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//
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if (GV->hasName() && (V = ST->lookup(GV->getType(), GV->getName()))) {
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// The same named thing is a global variable, because the only two things
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// that may be in a module level symbol table are Global Vars and Methods,
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// and they both have distinct, nonoverlapping, possible types.
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//
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GlobalVariable *DGV = cast<GlobalVariable>(V);
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// Check to see if the two GV's have the same Const'ness...
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if (GV->isConstant() != DGV->isConstant())
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return Error(Err, "Global Variable Collision on '" +
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GV->getType()->getDescription() + "':%" + GV->getName() +
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" - Global variables differ in const'ness");
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// Check to make sure that they both have the same initializer if they are
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// both initialized...
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//
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// TODO: Check to see if they have DEEP equality. For Module level constants
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if (GV->hasInitializer() && DGV->hasInitializer() &&
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GV->getInitializer() != DGV->getInitializer())
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return Error(Err, "Global Variable Collision on '" +
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GV->getType()->getDescription() + "':%" + GV->getName() +
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" - Global variables have different initializers");
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// Okay, everything is cool, remember the mapping and update the
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// initializer if neccesary...
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//
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// TODO: We might have to map module level constants here!
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if (GV->hasInitializer() && !DGV->hasInitializer())
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DGV->setInitializer(GV->getInitializer());
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ValueMap.insert(make_pair(GV, DGV));
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} else {
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// No linking to be performed, simply create an identical version of the
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// symbol over in the dest module...
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// TODO: Provide constpoolval mapping for initializer if using module local
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// initializers!
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GlobalVariable *NGV =
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new GlobalVariable(GV->getType()->getValueType(), GV->isConstant(),
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GV->hasInitializer() ? GV->getInitializer() : 0,
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GV->getName());
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// Add the new global to the dest module
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Dest->getGlobalList().push_back(NGV);
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// Make sure to remember this mapping...
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ValueMap.insert(make_pair(GV, NGV));
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}
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}
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return false;
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}
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// LinkMethodProtos - Link the methods together between the two modules, without
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// doing method bodies... this just adds external method prototypes to the Dest
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// method...
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//
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static bool LinkMethodProtos(Module *Dest, const Module *Src,
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map<const Value*, Value*> &ValueMap,
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string *Err = 0) {
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// We will need a module level symbol table if the src module has a module
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// level symbol table...
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SymbolTable *ST = Src->getSymbolTable() ? Dest->getSymbolTableSure() : 0;
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// Loop over all of the methods in the src module, mapping them over as we go
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//
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for (Module::const_iterator I = Src->begin(), E = Src->end(); I != E; ++I) {
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const Method *SM = *I; // SrcMethod
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Value *V;
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// If the method has a name, and that name is already in use in the
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// Dest module, make sure that the name is a compatible method...
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//
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if (SM->hasName() && (V = ST->lookup(SM->getType(), SM->getName()))) {
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// The same named thing is a Method, because the only two things
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// that may be in a module level symbol table are Global Vars and Methods,
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// and they both have distinct, nonoverlapping, possible types.
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//
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Method *DM = cast<Method>(V); // DestMethod
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// Check to make sure the method is not defined in both modules...
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if (!SM->isExternal() && !DM->isExternal())
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return Error(Err, "Method '" +
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SM->getMethodType()->getDescription() + "':\"" +
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SM->getName() + "\" - Method is already defined!");
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// Otherwise, just remember this mapping...
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ValueMap.insert(make_pair(SM, DM));
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} else {
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// Method does not already exist, simply insert an external method
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// signature identical to SM into the dest module...
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Method *DM = new Method(SM->getMethodType(), SM->getName());
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// Add the method signature to the dest module...
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Dest->getMethodList().push_back(DM);
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// ... and remember this mapping...
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ValueMap.insert(make_pair(SM, DM));
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}
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}
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return false;
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}
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// LinkMethodBody - Copy the source method over into the dest method and fix up
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// references to values. At this point we know that Dest is an external method,
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// and that Src is not.
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//
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static bool LinkMethodBody(Method *Dest, const Method *Src,
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const map<const Value*, Value*> &GlobalMap,
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string *Err = 0) {
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assert(Src && Dest && Dest->isExternal() && !Src->isExternal());
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map<const Value*, Value*> LocalMap; // Map for method local values
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// Go through and convert method arguments over...
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for (Method::ArgumentListType::const_iterator
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I = Src->getArgumentList().begin(),
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E = Src->getArgumentList().end(); I != E; ++I) {
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const MethodArgument *SMA = *I;
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// Create the new method argument and add to the dest method...
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MethodArgument *DMA = new MethodArgument(SMA->getType(), SMA->getName());
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Dest->getArgumentList().push_back(DMA);
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// Add a mapping to our local map
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LocalMap.insert(make_pair(SMA, DMA));
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}
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// Loop over all of the basic blocks, copying the instructions over...
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//
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for (Method::const_iterator I = Src->begin(), E = Src->end(); I != E; ++I) {
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const BasicBlock *SBB = *I;
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// Create new basic block and add to mapping and the Dest method...
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BasicBlock *DBB = new BasicBlock(SBB->getName(), Dest);
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LocalMap.insert(make_pair(SBB, DBB));
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// Loop over all of the instructions in the src basic block, copying them
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// over. Note that this is broken in a strict sense because the cloned
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// instructions will still be referencing values in the Src module, not
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// the remapped values. In our case, however, we will not get caught and
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// so we can delay patching the values up until later...
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//
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for (BasicBlock::const_iterator II = SBB->begin(), IE = SBB->end();
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II != IE; ++II) {
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const Instruction *SI = *II;
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Instruction *DI = SI->clone();
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DBB->getInstList().push_back(DI);
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LocalMap.insert(make_pair(SI, DI));
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}
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}
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// At this point, all of the instructions and values of the method are now
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// copied over. The only problem is that they are still referencing values
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// in the Source method as operands. Loop through all of the operands of the
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// methods and patch them up to point to the local versions...
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//
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for (Method::inst_iterator I = Dest->inst_begin(), E = Dest->inst_end();
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I != E; ++I) {
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Instruction *Inst = *I;
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for (Instruction::op_iterator OI = Inst->op_begin(), OE = Inst->op_end();
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OI != OE; ++OI)
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*OI = RemapOperand(*OI, LocalMap, &GlobalMap);
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}
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return false;
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}
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// LinkMethodBodies - Link in the method bodies that are defined in the source
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// module into the DestModule. This consists basically of copying the method
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// over and fixing up references to values.
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//
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static bool LinkMethodBodies(Module *Dest, const Module *Src,
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map<const Value*, Value*> &ValueMap,
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string *Err = 0) {
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// Loop over all of the methods in the src module, mapping them over as we go
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//
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for (Module::const_iterator I = Src->begin(), E = Src->end(); I != E; ++I) {
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const Method *SM = *I; // Source Method
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Method *DM = cast<Method>(ValueMap[SM]); // Destination method
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assert(DM && DM->isExternal() && "LinkMethodProtos failed!");
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if (!SM->isExternal()) // External methods are already done
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if (LinkMethodBody(DM, SM, ValueMap, Err)) return true;
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}
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return false;
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}
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// LinkModules - This function links two modules together, with the resulting
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// left module modified to be the composite of the two input modules. If an
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// error occurs, true is returned and ErrorMsg (if not null) is set to indicate
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// the problem. Upon failure, the Dest module could be in a modified state, and
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// shouldn't be relied on to be consistent.
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//
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bool LinkModules(Module *Dest, const Module *Src, string *ErrorMsg = 0) {
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// ValueMap - Mapping of values from what they used to be in Src, to what they
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// are now in Dest.
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//
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map<const Value*, Value*> ValueMap;
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// Link the globals variables together between the two modules...
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if (LinkGlobals(Dest, Src, ValueMap, ErrorMsg)) return true;
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// Link the methods together between the two modules, without doing method
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// bodies... this just adds external method prototypes to the Dest method...
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// We do this so that when we begin processing method bodies, all of the
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// global values that may be referenced are available in our ValueMap.
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//
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if (LinkMethodProtos(Dest, Src, ValueMap, ErrorMsg)) return true;
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// Link in the method bodies that are defined in the source module into the
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// DestModule. This consists basically of copying the method over and fixing
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// up references to values.
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//
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if (LinkMethodBodies(Dest, Src, ValueMap, ErrorMsg)) return true;
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return false;
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}
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