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Implement linker. It's 95% working now.

llvm-svn: 810
This commit is contained in:
Chris Lattner 2001-10-14 23:29:15 +00:00
parent fcc8c249da
commit 9f4d1bcb25

View File

@ -9,14 +9,280 @@
//===----------------------------------------------------------------------===//
#include "llvm/Transforms/Linker.h"
#include "llvm/Module.h"
#include "llvm/Method.h"
#include "llvm/GlobalVariable.h"
#include "llvm/SymbolTable.h"
#include "llvm/DerivedTypes.h"
#include "llvm/iOther.h"
// 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;
}
#include "llvm/Assembly/Writer.h" // TODO: REMOVE
// 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(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;
}
if (!isa<ConstPoolVal>(In))
cerr << "Couldn't remap value: " << In << endl;
return In;
}
// 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 *GV = *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 (GV->hasName() && (V = ST->lookup(GV->getType(), GV->getName()))) {
// 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 Methods,
// 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 (GV->isConstant() != DGV->isConstant())
return Error(Err, "Global Variable Collision on '" +
GV->getType()->getDescription() + "':%" + GV->getName() +
" - Global variables differ in const'ness");
// Check to make sure that they both have the same initializer if they are
// both initialized...
//
// TODO: Check to see if they have DEEP equality. For Module level constants
if (GV->hasInitializer() && DGV->hasInitializer() &&
GV->getInitializer() != DGV->getInitializer())
return Error(Err, "Global Variable Collision on '" +
GV->getType()->getDescription() + "':%" + GV->getName() +
" - Global variables have different initializers");
// Okay, everything is cool, remember the mapping and update the
// initializer if neccesary...
//
// TODO: We might have to map module level constants here!
if (GV->hasInitializer() && !DGV->hasInitializer())
DGV->setInitializer(GV->getInitializer());
ValueMap.insert(make_pair(GV, DGV));
} else {
// No linking to be performed, simply create an identical version of the
// symbol over in the dest module...
// TODO: Provide constpoolval mapping for initializer if using module local
// initializers!
GlobalVariable *NGV =
new GlobalVariable(GV->getType()->getValueType(), GV->isConstant(),
GV->hasInitializer() ? GV->getInitializer() : 0,
GV->getName());
// Add the new global to the dest module
Dest->getGlobalList().push_back(NGV);
// Make sure to remember this mapping...
ValueMap.insert(make_pair(GV, NGV));
}
}
return false;
}
// LinkMethodProtos - Link the methods together between the two modules, without
// doing method bodies... this just adds external method prototypes to the Dest
// method...
//
static bool LinkMethodProtos(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 Method *SM = *I; // SrcMethod
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->hasName() && (V = ST->lookup(SM->getType(), SM->getName()))) {
// The same named thing is a Method, because the only two things
// that may be in a module level symbol table are Global Vars and Methods,
// and they both have distinct, nonoverlapping, possible types.
//
Method *DM = cast<Method>(V); // DestMethod
// Check to make sure the method is not defined in both modules...
if (!SM->isExternal() && !DM->isExternal())
return Error(Err, "Method '" +
SM->getMethodType()->getDescription() + "':\"" +
SM->getName() + "\" - Method is already defined!");
// Otherwise, just remember this mapping...
ValueMap.insert(make_pair(SM, DM));
} else {
// Method does not already exist, simply insert an external method
// signature identical to SM into the dest module...
Method *DM = new Method(SM->getMethodType(), SM->getName());
// Add the method signature to the dest module...
Dest->getMethodList().push_back(DM);
// ... and remember this mapping...
ValueMap.insert(make_pair(SM, DM));
}
}
return false;
}
// LinkMethodBody - 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 LinkMethodBody(Method *Dest, const Method *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 (Method::ArgumentListType::const_iterator
I = Src->getArgumentList().begin(),
E = Src->getArgumentList().end(); I != E; ++I) {
const MethodArgument *SMA = *I;
// Create the new method argument and add to the dest method...
MethodArgument *DMA = new MethodArgument(SMA->getType(), SMA->getName());
Dest->getArgumentList().push_back(DMA);
// Add a mapping to our local map
LocalMap.insert(make_pair(SMA, DMA));
}
// Loop over all of the basic blocks, copying the instructions over...
//
for (Method::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(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();
DBB->getInstList().push_back(DI);
LocalMap.insert(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 (Method::inst_iterator I = Dest->inst_begin(), E = Dest->inst_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;
}
// LinkMethodBodies - 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 LinkMethodBodies(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 Method *SM = *I; // Source Method
Method *DM = cast<Method>(ValueMap[SM]); // Destination method
assert(DM && DM->isExternal() && "LinkMethodProtos failed!");
if (!SM->isExternal()) // External methods are already done
if (LinkMethodBody(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.
// 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) {
// ValueMap - Mapping of values from what they used to be in Src, to what they
// are now in Dest.
//
map<const Value*, Value*> ValueMap;
// Link the globals variables together between the two modules...
if (LinkGlobals(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 (LinkMethodProtos(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 (LinkMethodBodies(Dest, Src, ValueMap, ErrorMsg)) return true;
return false;
}