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Implement FunctionResolve/2003-10-21-GlobalResolveHack.ll

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@9363 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2003-10-22 03:35:34 +00:00
parent f4e643ffe0
commit efd47ba3ac
1 changed files with 34 additions and 2 deletions
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36
lib/Transforms/IPO/FunctionResolution.cpp
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@ -25,6 +25,7 @@
#include "llvm/Pass.h"
#include "llvm/iOther.h"
#include "llvm/Constants.h"
#include "llvm/Target/TargetData.h"
#include "llvm/Assembly/Writer.h"
#include "Support/Statistic.h"
#include <algorithm>
@ -34,6 +35,10 @@ namespace {
Statistic<> NumGlobals("funcresolve", "Number of global variables resolved");
struct FunctionResolvingPass : public Pass {
virtual void getAnalysisUsage(AnalysisUsage &AU) const {
AU.addRequired<TargetData>();
}
bool run(Module &M);
};
RegisterOpt<FunctionResolvingPass> X("funcresolve", "Resolve Functions");
@ -125,7 +130,7 @@ static bool ResolveGlobalVariables(Module &M,
return Changed;
}
static bool ProcessGlobalsWithSameName(Module &M,
static bool ProcessGlobalsWithSameName(Module &M, TargetData &TD,
std::vector<GlobalValue*> &Globals) {
assert(!Globals.empty() && "Globals list shouldn't be empty here!");
@ -202,6 +207,31 @@ static bool ProcessGlobalsWithSameName(Module &M,
if (!Concrete)
Concrete = Globals[0];
else if (GlobalVariable *GV = dyn_cast<GlobalVariable>(Concrete)) {
// Handle special case hack to change globals if it will make their types
// happier in the long run. The situation we do this is intentionally
// extremely limited.
if (GV->use_empty() && GV->hasInitializer() &&
GV->getInitializer()->isNullValue()) {
// Check to see if there is another (external) global with the same size
// and a non-empty use-list. If so, we will make IT be the real
// implementation.
unsigned TS = TD.getTypeSize(Concrete->getType()->getElementType());
for (unsigned i = 0, e = Globals.size(); i != e; ++i)
if (Globals[i] != Concrete && !Globals[i]->use_empty() &&
isa<GlobalVariable>(Globals[i]) &&
TD.getTypeSize(Globals[i]->getType()->getElementType()) == TS) {
// At this point we want to replace Concrete with Globals[i]. Make
// concrete external, and Globals[i] have an initializer.
GlobalVariable *NGV = cast<GlobalVariable>(Globals[i]);
const Type *ElTy = NGV->getType()->getElementType();
NGV->setInitializer(Constant::getNullValue(ElTy));
cast<GlobalVariable>(Concrete)->setInitializer(0);
Concrete = NGV;
break;
}
}
}
if (isFunction)
return ResolveFunctions(M, Globals, cast<Function>(Concrete));
@ -236,12 +266,14 @@ bool FunctionResolvingPass::run(Module &M) {
bool Changed = false;
TargetData &TD = getAnalysis<TargetData>();
// Now we have a list of all functions with a particular name. If there is
// more than one entry in a list, merge the functions together.
//
for (std::map<std::string, std::vector<GlobalValue*> >::iterator
I = Globals.begin(), E = Globals.end(); I != E; ++I)
Changed |= ProcessGlobalsWithSameName(M, I->second);
Changed |= ProcessGlobalsWithSameName(M, TD, I->second);
// Now loop over all of the globals, checking to see if any are trivially
// dead. If so, remove them now.