llvm-6502/lib/VMCore/Linker.cpp

436 lines
17 KiB
C++
Raw Normal View History

//===- Linker.cpp - Module Linker Implementation --------------------------===//
//
// This file implements the LLVM module linker.
//
// Specifically, this:
// * Merges global variables between the two modules
// * Uninit + Uninit = Init, Init + Uninit = Init, Init + Init = Error if !=
// * Merges methods between two modules
//
//===----------------------------------------------------------------------===//
#include "llvm/Transforms/Linker.h"
#include "llvm/Module.h"
#include "llvm/Function.h"
#include "llvm/BasicBlock.h"
#include "llvm/GlobalVariable.h"
#include "llvm/SymbolTable.h"
#include "llvm/DerivedTypes.h"
#include "llvm/iOther.h"
#include "llvm/ConstantVals.h"
#include "llvm/Argument.h"
#include <iostream>
using std::cerr;
using std::string;
using std::map;
// Error - Simple wrapper function to conditionally assign to E and return true.
// This just makes error return conditions a little bit simpler...
//
static inline bool Error(string *E, string Message) {
if (E) *E = Message;
return true;
}
// LinkTypes - Go through the symbol table of the Src module and see if any
// types are named in the src module that are not named in the Dst module.
// Make sure there are no type name conflicts.
//
static bool LinkTypes(Module *Dest, const Module *Src, string *Err = 0) {
// No symbol table? Can't have named types.
if (!Src->hasSymbolTable()) return false;
SymbolTable *DestST = Dest->getSymbolTableSure();
const SymbolTable *SrcST = Src->getSymbolTable();
// Look for a type plane for Type's...
SymbolTable::const_iterator PI = SrcST->find(Type::TypeTy);
if (PI == SrcST->end()) return false; // No named types, do nothing.
const SymbolTable::VarMap &VM = PI->second;
for (SymbolTable::type_const_iterator I = VM.begin(), E = VM.end();
I != E; ++I) {
const string &Name = I->first;
const Type *RHS = cast<Type>(I->second);
// Check to see if this type name is already in the dest module...
const Type *Entry = cast_or_null<Type>(DestST->lookup(Type::TypeTy, Name));
if (Entry) { // Yup, the value already exists...
if (Entry != RHS) // If it's the same, noop. Otherwise, error.
return Error(Err, "Type named '" + Name +
"' of different shape in modules.\n Src='" +
Entry->getDescription() + "'.\n Dst='" +
RHS->getDescription() + "'");
} else { // Type not in dest module. Add it now.
// TODO: FIXME WHEN TYPES AREN'T CONST
DestST->insert(Name, const_cast<Type*>(RHS));
}
}
return false;
}
static void PrintMap(const map<const Value*, Value*> &M) {
for (map<const Value*, Value*>::const_iterator I = M.begin(), E = M.end();
I != E; ++I) {
cerr << " Fr: " << (void*)I->first << " ";
I->first->dump();
cerr << " To: " << (void*)I->second << " ";
I->second->dump();
cerr << "\n";
}
}
// RemapOperand - Use LocalMap and GlobalMap to convert references from one
// module to another. This is somewhat sophisticated in that it can
// automatically handle constant references correctly as well...
//
static Value *RemapOperand(const Value *In, map<const Value*, Value*> &LocalMap,
const map<const Value*, Value*> *GlobalMap = 0) {
map<const Value*,Value*>::const_iterator I = LocalMap.find(In);
if (I != LocalMap.end()) return I->second;
if (GlobalMap) {
I = GlobalMap->find(In);
if (I != GlobalMap->end()) return I->second;
}
// Check to see if it's a constant that we are interesting in transforming...
if (Constant *CPV = dyn_cast<Constant>(In)) {
if (!isa<DerivedType>(CPV->getType()))
return CPV; // Simple constants stay identical...
Constant *Result = 0;
if (ConstantArray *CPA = dyn_cast<ConstantArray>(CPV)) {
const std::vector<Use> &Ops = CPA->getValues();
std::vector<Constant*> Operands(Ops.size());
for (unsigned i = 0; i < Ops.size(); ++i)
Operands[i] =
cast<Constant>(RemapOperand(Ops[i], LocalMap, GlobalMap));
Result = ConstantArray::get(cast<ArrayType>(CPA->getType()), Operands);
} else if (ConstantStruct *CPS = dyn_cast<ConstantStruct>(CPV)) {
const std::vector<Use> &Ops = CPS->getValues();
std::vector<Constant*> Operands(Ops.size());
for (unsigned i = 0; i < Ops.size(); ++i)
Operands[i] =
cast<Constant>(RemapOperand(Ops[i], LocalMap, GlobalMap));
Result = ConstantStruct::get(cast<StructType>(CPS->getType()), Operands);
} else if (isa<ConstantPointerNull>(CPV)) {
Result = CPV;
} else if (ConstantPointerRef *CPR = dyn_cast<ConstantPointerRef>(CPV)) {
Value *V = RemapOperand(CPR->getValue(), LocalMap, GlobalMap);
Result = ConstantPointerRef::get(cast<GlobalValue>(V));
} else {
assert(0 && "Unknown type of derived type constant value!");
}
// Cache the mapping in our local map structure...
LocalMap.insert(std::make_pair(In, CPV));
return Result;
}
cerr << "XXX LocalMap: \n";
PrintMap(LocalMap);
if (GlobalMap) {
cerr << "XXX GlobalMap: \n";
PrintMap(*GlobalMap);
}
cerr << "Couldn't remap value: " << (void*)In << " ";
In->dump();
cerr << "\n";
assert(0 && "Couldn't remap value!");
return 0;
}
// LinkGlobals - Loop through the global variables in the src module and merge
// them into the dest module...
//
static bool LinkGlobals(Module *Dest, const Module *Src,
map<const Value*, Value*> &ValueMap, string *Err = 0) {
// We will need a module level symbol table if the src module has a module
// level symbol table...
SymbolTable *ST = Src->getSymbolTable() ? Dest->getSymbolTableSure() : 0;
// Loop over all of the globals in the src module, mapping them over as we go
//
for (Module::const_giterator I = Src->gbegin(), E = Src->gend(); I != E; ++I){
const GlobalVariable *SGV = *I;
Value *V;
// If the global variable has a name, and that name is already in use in the
// Dest module, make sure that the name is a compatible global variable...
//
if (SGV->hasExternalLinkage() && SGV->hasName() &&
(V = ST->lookup(SGV->getType(), SGV->getName())) &&
cast<GlobalVariable>(V)->hasExternalLinkage()) {
// The same named thing is a global variable, because the only two things
// that may be in a module level symbol table are Global Vars and
// Functions, and they both have distinct, nonoverlapping, possible types.
//
GlobalVariable *DGV = cast<GlobalVariable>(V);
// Check to see if the two GV's have the same Const'ness...
if (SGV->isConstant() != DGV->isConstant())
return Error(Err, "Global Variable Collision on '" +
SGV->getType()->getDescription() + "':%" + SGV->getName() +
" - Global variables differ in const'ness");
// Okay, everything is cool, remember the mapping...
ValueMap.insert(std::make_pair(SGV, DGV));
} else {
// No linking to be performed, simply create an identical version of the
// symbol over in the dest module... the initializer will be filled in
// later by LinkGlobalInits...
//
GlobalVariable *DGV =
new GlobalVariable(SGV->getType()->getElementType(), SGV->isConstant(),
SGV->hasInternalLinkage(), 0, SGV->getName());
// Add the new global to the dest module
Dest->getGlobalList().push_back(DGV);
// Make sure to remember this mapping...
ValueMap.insert(std::make_pair(SGV, DGV));
}
}
return false;
}
// LinkGlobalInits - Update the initializers in the Dest module now that all
// globals that may be referenced are in Dest.
//
static bool LinkGlobalInits(Module *Dest, const Module *Src,
map<const Value*, Value*> &ValueMap,
string *Err = 0) {
// Loop over all of the globals in the src module, mapping them over as we go
//
for (Module::const_giterator I = Src->gbegin(), E = Src->gend(); I != E; ++I){
const GlobalVariable *SGV = *I;
if (SGV->hasInitializer()) { // Only process initialized GV's
// Figure out what the initializer looks like in the dest module...
Constant *DInit =
cast<Constant>(RemapOperand(SGV->getInitializer(), ValueMap));
GlobalVariable *DGV = cast<GlobalVariable>(ValueMap[SGV]);
if (DGV->hasInitializer() && SGV->hasExternalLinkage() &&
DGV->hasExternalLinkage()) {
if (DGV->getInitializer() != DInit)
return Error(Err, "Global Variable Collision on '" +
SGV->getType()->getDescription() + "':%" +SGV->getName()+
" - Global variables have different initializers");
} else {
// Copy the initializer over now...
DGV->setInitializer(DInit);
}
}
}
return false;
}
// LinkFunctionProtos - Link the functions together between the two modules,
// without doing method bodies... this just adds external method prototypes to
// the Dest function...
//
static bool LinkFunctionProtos(Module *Dest, const Module *Src,
map<const Value*, Value*> &ValueMap,
string *Err = 0) {
// We will need a module level symbol table if the src module has a module
// level symbol table...
SymbolTable *ST = Src->getSymbolTable() ? Dest->getSymbolTableSure() : 0;
// Loop over all of the methods in the src module, mapping them over as we go
//
for (Module::const_iterator I = Src->begin(), E = Src->end(); I != E; ++I) {
const Function *SM = *I; // SrcFunction
Value *V;
// If the method has a name, and that name is already in use in the
// Dest module, make sure that the name is a compatible method...
//
if (SM->hasExternalLinkage() && SM->hasName() &&
(V = ST->lookup(SM->getType(), SM->getName())) &&
cast<Function>(V)->hasExternalLinkage()) {
// The same named thing is a Function, because the only two things
// that may be in a module level symbol table are Global Vars and
// Functions, and they both have distinct, nonoverlapping, possible types.
//
Function *DM = cast<Function>(V); // DestFunction
// Check to make sure the method is not defined in both modules...
if (!SM->isExternal() && !DM->isExternal())
return Error(Err, "Function '" +
SM->getFunctionType()->getDescription() + "':\"" +
SM->getName() + "\" - Function is already defined!");
// Otherwise, just remember this mapping...
ValueMap.insert(std::make_pair(SM, DM));
} else {
// Function does not already exist, simply insert an external method
// signature identical to SM into the dest module...
Function *DM = new Function(SM->getFunctionType(),
SM->hasInternalLinkage(),
SM->getName());
// Add the method signature to the dest module...
Dest->getFunctionList().push_back(DM);
// ... and remember this mapping...
ValueMap.insert(std::make_pair(SM, DM));
}
}
return false;
}
// LinkFunctionBody - Copy the source method over into the dest method
// and fix up references to values. At this point we know that Dest
// is an external method, and that Src is not.
//
static bool LinkFunctionBody(Function *Dest, const Function *Src,
const map<const Value*, Value*> &GlobalMap,
string *Err = 0) {
assert(Src && Dest && Dest->isExternal() && !Src->isExternal());
map<const Value*, Value*> LocalMap; // Map for method local values
// Go through and convert method arguments over...
for (Function::ArgumentListType::const_iterator
I = Src->getArgumentList().begin(),
E = Src->getArgumentList().end(); I != E; ++I) {
const Argument *SMA = *I;
// Create the new method argument and add to the dest method...
Argument *DMA = new Argument(SMA->getType(), SMA->getName());
Dest->getArgumentList().push_back(DMA);
// Add a mapping to our local map
LocalMap.insert(std::make_pair(SMA, DMA));
}
// Loop over all of the basic blocks, copying the instructions over...
//
for (Function::const_iterator I = Src->begin(), E = Src->end(); I != E; ++I) {
const BasicBlock *SBB = *I;
// Create new basic block and add to mapping and the Dest method...
BasicBlock *DBB = new BasicBlock(SBB->getName(), Dest);
LocalMap.insert(std::make_pair(SBB, DBB));
// Loop over all of the instructions in the src basic block, copying them
// over. Note that this is broken in a strict sense because the cloned
// instructions will still be referencing values in the Src module, not
// the remapped values. In our case, however, we will not get caught and
// so we can delay patching the values up until later...
//
for (BasicBlock::const_iterator II = SBB->begin(), IE = SBB->end();
II != IE; ++II) {
const Instruction *SI = *II;
Instruction *DI = SI->clone();
DI->setName(SI->getName());
DBB->getInstList().push_back(DI);
LocalMap.insert(std::make_pair(SI, DI));
}
}
// At this point, all of the instructions and values of the method are now
// copied over. The only problem is that they are still referencing values
// in the Source method as operands. Loop through all of the operands of the
// methods and patch them up to point to the local versions...
//
for (Function::iterator BI = Dest->begin(), BE = Dest->end();
BI != BE; ++BI) {
BasicBlock *BB = *BI;
for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I) {
Instruction *Inst = *I;
for (Instruction::op_iterator OI = Inst->op_begin(), OE = Inst->op_end();
OI != OE; ++OI)
*OI = RemapOperand(*OI, LocalMap, &GlobalMap);
}
}
return false;
}
// LinkFunctionBodies - Link in the method bodies that are defined in the source
// module into the DestModule. This consists basically of copying the method
// over and fixing up references to values.
//
static bool LinkFunctionBodies(Module *Dest, const Module *Src,
map<const Value*, Value*> &ValueMap,
string *Err = 0) {
// Loop over all of the methods in the src module, mapping them over as we go
//
for (Module::const_iterator I = Src->begin(), E = Src->end(); I != E; ++I) {
const Function *SM = *I; // Source Function
if (!SM->isExternal()) { // No body if method is external
Function *DM = cast<Function>(ValueMap[SM]); // Destination method
// DM not external SM external?
if (!DM->isExternal()) {
if (Err)
*Err = "Function '" + (SM->hasName() ? SM->getName() : string("")) +
"' body multiply defined!";
return true;
}
if (LinkFunctionBody(DM, SM, ValueMap, Err)) return true;
}
}
return false;
}
// LinkModules - This function links two modules together, with the resulting
// left module modified to be the composite of the two input modules. If an
// error occurs, true is returned and ErrorMsg (if not null) is set to indicate
// the problem. Upon failure, the Dest module could be in a modified state, and
// shouldn't be relied on to be consistent.
//
bool LinkModules(Module *Dest, const Module *Src, string *ErrorMsg = 0) {
// LinkTypes - Go through the symbol table of the Src module and see if any
// types are named in the src module that are not named in the Dst module.
// Make sure there are no type name conflicts.
//
if (LinkTypes(Dest, Src, ErrorMsg)) return true;
// ValueMap - Mapping of values from what they used to be in Src, to what they
// are now in Dest.
//
map<const Value*, Value*> ValueMap;
// Insert all of the globals in src into the Dest module... without
// initializers
if (LinkGlobals(Dest, Src, ValueMap, ErrorMsg)) return true;
// Update the initializers in the Dest module now that all globals that may
// be referenced are in Dest.
//
if (LinkGlobalInits(Dest, Src, ValueMap, ErrorMsg)) return true;
// Link the methods together between the two modules, without doing method
// bodies... this just adds external method prototypes to the Dest method...
// We do this so that when we begin processing method bodies, all of the
// global values that may be referenced are available in our ValueMap.
//
if (LinkFunctionProtos(Dest, Src, ValueMap, ErrorMsg)) return true;
// Link in the method bodies that are defined in the source module into the
// DestModule. This consists basically of copying the method over and fixing
// up references to values.
//
if (LinkFunctionBodies(Dest, Src, ValueMap, ErrorMsg)) return true;
return false;
}