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Implement linkage of appending global variables! 

llvm-svn: 6178
This commit is contained in:
Chris Lattner 2003-05-13 21:33:43 +00:00
parent 83dff9da0a
commit f779becc5a
1 changed files with 115 additions and 6 deletions
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121
llvm/lib/Transforms/Utils/Linker.cpp
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@ -19,7 +19,7 @@
// 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(std::string *E, std::string Message) {
static inline bool Error(std::string *E, const std::string &Message) {
if (E) *E = Message;
return true;
}
@ -176,10 +176,11 @@ static Value *RemapOperand(const Value *In,
// LinkGlobals - Loop through the global variables in the src module and merge
// them into the dest module...
// them into the dest module.
//
static bool LinkGlobals(Module *Dest, const Module *Src,
std::map<const Value*, Value*> &ValueMap,
std::multimap<std::string, GlobalVariable *> &AppendingVars,
std::string *Err) {
// We will need a module level symbol table if the src module has a module
// level symbol table...
@ -230,6 +231,10 @@ static bool LinkGlobals(Module *Dest, const Module *Src,
// Make sure to remember this mapping...
ValueMap.insert(std::make_pair(SGV, NewDGV));
if (SGV->hasAppendingLinkage())
// Keep track that this is an appending variable...
AppendingVars.insert(std::make_pair(SGV->getName(), NewDGV));
} else if (SGV->isExternal()) {
// If SGV is external or if both SGV & DGV are external.. Just link the
// external globals, we aren't adding anything.
@ -263,7 +268,20 @@ static bool LinkGlobals(Module *Dest, const Module *Src,
// Okay, everything is cool, remember the mapping...
ValueMap.insert(std::make_pair(SGV, DGV));
} else if (SGV->hasAppendingLinkage()) {
assert(0 && "FIXME: Appending linkage unimplemented!");
// No linking is performed yet. Just insert a new copy of the global, and
// keep track of the fact that it is an appending variable in the
// AppendingVars map. The name is cleared out so that no linkage is
// performed.
GlobalVariable *NewDGV =
new GlobalVariable(SGV->getType()->getElementType(),
SGV->isConstant(), SGV->getLinkage(), /*init*/0,
"", Dest);
// Make sure to remember this mapping...
ValueMap.insert(std::make_pair(SGV, NewDGV));
// Keep track that this is an appending variable...
AppendingVars.insert(std::make_pair(SGV->getName(), NewDGV));
} else {
assert(0 && "Unknown linkage!");
}
@ -470,6 +488,81 @@ static bool LinkFunctionBodies(Module *Dest, const Module *Src,
return false;
}
// LinkAppendingVars - If there were any appending global variables, link them
// together now. Return true on error.
//
static bool LinkAppendingVars(Module *M,
std::multimap<std::string, GlobalVariable *> &AppendingVars,
std::string *ErrorMsg) {
if (AppendingVars.empty()) return false; // Nothing to do.
// Loop over the multimap of appending vars, processing any variables with the
// same name, forming a new appending global variable with both of the
// initializers merged together, then rewrite references to the old variables
// and delete them.
//
std::vector<Constant*> Inits;
while (AppendingVars.size() > 1) {
// Get the first two elements in the map...
std::multimap<std::string,
GlobalVariable*>::iterator Second = AppendingVars.begin(), First=Second++;
// If the first two elements are for different names, there is no pair...
// Otherwise there is a pair, so link them together...
if (First->first == Second->first) {
GlobalVariable *G1 = First->second, *G2 = Second->second;
const ArrayType *T1 = cast<ArrayType>(G1->getType()->getElementType());
const ArrayType *T2 = cast<ArrayType>(G2->getType()->getElementType());
// Check to see that they two arrays agree on type...
if (T1->getElementType() != T2->getElementType())
return Error(ErrorMsg,
"Appending variables with different element types need to be linked!");
if (G1->isConstant() != G2->isConstant())
return Error(ErrorMsg,
"Appending variables linked with different const'ness!");
unsigned NewSize = T1->getNumElements() + T2->getNumElements();
ArrayType *NewType = ArrayType::get(T1->getElementType(), NewSize);
// Create the new global variable...
GlobalVariable *NG =
new GlobalVariable(NewType, G1->isConstant(), G1->getLinkage(),
/*init*/0, First->first, M);
// Merge the initializer...
Inits.reserve(NewSize);
ConstantArray *I = cast<ConstantArray>(G1->getInitializer());
for (unsigned i = 0, e = T1->getNumElements(); i != e; ++i)
Inits.push_back(cast<Constant>(I->getValues()[i]));
I = cast<ConstantArray>(G2->getInitializer());
for (unsigned i = 0, e = T2->getNumElements(); i != e; ++i)
Inits.push_back(cast<Constant>(I->getValues()[i]));
NG->setInitializer(ConstantArray::get(NewType, Inits));
Inits.clear();
// Replace any uses of the two global variables with uses of the new
// global...
// FIXME: This should rewrite simple/straight-forward uses such as
// getelementptr instructions to not use the Cast!
ConstantPointerRef *NGCP = ConstantPointerRef::get(NG);
G1->replaceAllUsesWith(ConstantExpr::getCast(NGCP, G1->getType()));
G2->replaceAllUsesWith(ConstantExpr::getCast(NGCP, G2->getType()));
// Remove the two globals from the module now...
M->getGlobalList().erase(G1);
M->getGlobalList().erase(G2);
// Put the new global into the AppendingVars map so that we can handle
// linking of more than two vars...
Second->second = NG;
}
AppendingVars.erase(First);
}
return false;
}
// LinkModules - This function links two modules together, with the resulting
@ -495,9 +588,21 @@ bool LinkModules(Module *Dest, const Module *Src, std::string *ErrorMsg) {
//
std::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;
// AppendingVars - Keep track of global variables in the destination module
// with appending linkage. After the module is linked together, they are
// appended and the module is rewritten.
//
std::multimap<std::string, GlobalVariable *> AppendingVars;
// Add all of the appending globals already in the Dest module to
// AppendingVars.
for (Module::giterator I = Dest->gbegin(), E = Dest->gend(); I != E; ++I)
AppendingVars.insert(std::make_pair(I->getName(), I));
// Insert all of the globals in src into the Dest module... without linking
// initializers (which could refer to functions not yet mapped over).
//
if (LinkGlobals(Dest, Src, ValueMap, AppendingVars, ErrorMsg)) return true;
// Link the functions together between the two modules, without doing function
// bodies... this just adds external function prototypes to the Dest
@ -518,6 +623,10 @@ bool LinkModules(Module *Dest, const Module *Src, std::string *ErrorMsg) {
//
if (LinkFunctionBodies(Dest, Src, ValueMap, ErrorMsg)) return true;
// If there were any appending global variables, link them together now.
//
if (LinkAppendingVars(Dest, AppendingVars, ErrorMsg)) return true;
return false;
}