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This pass is no longer needed.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@33917 91177308-0d34-0410-b5e6-96231b3b80d8
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Reid Spencer 2007-02-05 20:41:05 +00:00
parent c19fbd6ec8
commit 15468bfc22
1 changed files with 0 additions and 363 deletions
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363
lib/Transforms/IPO/FunctionResolution.cpp
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//===- FunctionResolution.cpp - Resolve declarations to implementations ---===//
//
// The LLVM Compiler Infrastructure
//
// This file was developed by the LLVM research group and is distributed under
// the University of Illinois Open Source License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// Loop over the functions that are in the module and look for functions that
// have the same name. More often than not, there will be things like:
//
// declare void %foo(...)
// void %foo(int, int) { ... }
//
// because of the way things are declared in C. If this is the case, patch
// things up.
//
//===----------------------------------------------------------------------===//
#define DEBUG_TYPE "funcresolve"
#include "llvm/Transforms/IPO.h"
#include "llvm/Module.h"
#include "llvm/DerivedTypes.h"
#include "llvm/Pass.h"
#include "llvm/Instructions.h"
#include "llvm/Constants.h"
#include "llvm/Support/CallSite.h"
#include "llvm/Target/TargetData.h"
#include "llvm/Assembly/Writer.h"
#include "llvm/ADT/Statistic.h"
#include <algorithm>
using namespace llvm;
STATISTIC(NumResolved, "Number of varargs functions resolved");
STATISTIC(NumGlobals, "Number of global variables resolved");
namespace {
struct FunctionResolvingPass : public ModulePass {
virtual void getAnalysisUsage(AnalysisUsage &AU) const {
AU.addRequired<TargetData>();
}
bool runOnModule(Module &M);
};
RegisterPass<FunctionResolvingPass> X("funcresolve", "Resolve Functions");
}
ModulePass *llvm::createFunctionResolvingPass() {
return new FunctionResolvingPass();
}
static bool ResolveFunctions(Module &M, std::vector<GlobalValue*> &Globals,
Function *Concrete) {
bool Changed = false;
for (unsigned i = 0; i != Globals.size(); ++i)
if (Globals[i] != Concrete) {
Function *Old = cast<Function>(Globals[i]);
const FunctionType *OldFT = Old->getFunctionType();
const FunctionType *ConcreteFT = Concrete->getFunctionType();
if (OldFT->getNumParams() > ConcreteFT->getNumParams() &&
!ConcreteFT->isVarArg())
if (!Old->use_empty()) {
cerr << "WARNING: Linking function '" << Old->getName()
<< "' is causing arguments to be dropped.\n";
cerr << "WARNING: Prototype: ";
WriteAsOperand(*cerr.stream(), Old);
cerr << " resolved to ";
WriteAsOperand(*cerr.stream(), Concrete);
cerr << "\n";
}
// Check to make sure that if there are specified types, that they
// match...
//
unsigned NumArguments = std::min(OldFT->getNumParams(),
ConcreteFT->getNumParams());
if (!Old->use_empty() && !Concrete->use_empty())
for (unsigned i = 0; i < NumArguments; ++i)
if (OldFT->getParamType(i) != ConcreteFT->getParamType(i))
if (OldFT->getParamType(i)->getTypeID() !=
ConcreteFT->getParamType(i)->getTypeID()) {
cerr << "WARNING: Function [" << Old->getName()
<< "]: Parameter types conflict for: '";
WriteTypeSymbolic(*cerr.stream(), OldFT, &M);
cerr << "' (in "
<< Old->getParent()->getModuleIdentifier() << ") and '";
WriteTypeSymbolic(*cerr.stream(), ConcreteFT, &M);
cerr << "'(in "
<< Concrete->getParent()->getModuleIdentifier() << ")\n";
return Changed;
}
// Attempt to convert all of the uses of the old function to the concrete
// form of the function. If there is a use of the fn that we don't
// understand here we punt to avoid making a bad transformation.
//
// At this point, we know that the return values are the same for our two
// functions and that the Old function has no varargs fns specified. In
// otherwords it's just <retty> (...)
//
if (!Old->use_empty()) {
Value *Replacement = Concrete;
if (Concrete->getType() != Old->getType())
Replacement = ConstantExpr::getBitCast(Concrete, Old->getType());
NumResolved += Old->getNumUses();
Old->replaceAllUsesWith(Replacement);
}
// Since there are no uses of Old anymore, remove it from the module.
M.getFunctionList().erase(Old);
}
return Changed;
}
static bool ResolveGlobalVariables(Module &M,
std::vector<GlobalValue*> &Globals,
GlobalVariable *Concrete) {
bool Changed = false;
for (unsigned i = 0; i != Globals.size(); ++i)
if (Globals[i] != Concrete) {
Constant *Cast = ConstantExpr::getBitCast(Concrete,Globals[i]->getType());
Globals[i]->replaceAllUsesWith(Cast);
// Since there are no uses of Old anymore, remove it from the module.
M.getGlobalList().erase(cast<GlobalVariable>(Globals[i]));
++NumGlobals;
Changed = true;
}
return Changed;
}
// Check to see if all of the callers of F ignore the return value.
static bool CallersAllIgnoreReturnValue(Function &F) {
if (F.getReturnType() == Type::VoidTy) return true;
for (Value::use_iterator I = F.use_begin(), E = F.use_end(); I != E; ++I) {
if (GlobalValue *GV = dyn_cast<GlobalValue>(*I)) {
for (Value::use_iterator I = GV->use_begin(), E = GV->use_end();
I != E; ++I) {
CallSite CS = CallSite::get(*I);
if (!CS.getInstruction() || !CS.getInstruction()->use_empty())
return false;
}
} else {
CallSite CS = CallSite::get(*I);
if (!CS.getInstruction() || !CS.getInstruction()->use_empty())
return false;
}
}
return true;
}
static bool ProcessGlobalsWithSameName(Module &M, TargetData &TD,
std::vector<GlobalValue*> &Globals) {
assert(!Globals.empty() && "Globals list shouldn't be empty here!");
bool isFunction = isa<Function>(Globals[0]); // Is this group all functions?
GlobalValue *Concrete = 0; // The most concrete implementation to resolve to
for (unsigned i = 0; i != Globals.size(); ) {
if (isa<Function>(Globals[i]) != isFunction) {
cerr << "WARNING: Found function and global variable with the "
<< "same name: '" << Globals[i]->getName() << "'.\n";
return false; // Don't know how to handle this, bail out!
}
if (isFunction) {
// For functions, we look to merge functions definitions of "int (...)"
// to 'int (int)' or 'int ()' or whatever else is not completely generic.
//
Function *F = cast<Function>(Globals[i]);
if (!F->isDeclaration()) {
if (Concrete && !Concrete->isDeclaration())
return false; // Found two different functions types. Can't choose!
Concrete = Globals[i];
} else if (Concrete) {
if (Concrete->isDeclaration()) // If we have multiple external symbols...
if (F->getFunctionType()->getNumParams() >
cast<Function>(Concrete)->getFunctionType()->getNumParams())
Concrete = F; // We are more concrete than "Concrete"!
} else {
Concrete = F;
}
} else {
GlobalVariable *GV = cast<GlobalVariable>(Globals[i]);
if (!GV->isDeclaration()) {
if (Concrete) {
cerr << "WARNING: Two global variables with external linkage"
<< " exist with the same name: '" << GV->getName()
<< "'!\n";
return false;
}
Concrete = GV;
}
}
++i;
}
if (Globals.size() > 1) { // Found a multiply defined global...
// If there are no external declarations, and there is at most one
// externally visible instance of the global, then there is nothing to do.
//
bool HasExternal = false;
unsigned NumInstancesWithExternalLinkage = 0;
for (unsigned i = 0, e = Globals.size(); i != e; ++i) {
if (Globals[i]->isDeclaration())
HasExternal = true;
else if (!Globals[i]->hasInternalLinkage())
NumInstancesWithExternalLinkage++;
}
if (!HasExternal && NumInstancesWithExternalLinkage <= 1)
return false; // Nothing to do? Must have multiple internal definitions.
// There are a couple of special cases we don't want to print the warning
// for, check them now.
bool DontPrintWarning = false;
if (Concrete && Globals.size() == 2) {
GlobalValue *Other = Globals[Globals[0] == Concrete];
// If the non-concrete global is a function which takes (...) arguments,
// and the return values match (or was never used), do not warn.
if (Function *ConcreteF = dyn_cast<Function>(Concrete))
if (Function *OtherF = dyn_cast<Function>(Other))
if ((ConcreteF->getReturnType() == OtherF->getReturnType() ||
CallersAllIgnoreReturnValue(*OtherF)) &&
OtherF->getFunctionType()->isVarArg() &&
OtherF->getFunctionType()->getNumParams() == 0)
DontPrintWarning = true;
// Otherwise, if the non-concrete global is a global array variable with a
// size of 0, and the concrete global is an array with a real size, don't
// warn. This occurs due to declaring 'extern int A[];'.
if (GlobalVariable *ConcreteGV = dyn_cast<GlobalVariable>(Concrete))
if (GlobalVariable *OtherGV = dyn_cast<GlobalVariable>(Other)) {
const Type *CTy = ConcreteGV->getType();
const Type *OTy = OtherGV->getType();
if (CTy->isSized())
if (!OTy->isSized() || !TD.getTypeSize(OTy) ||
TD.getTypeSize(OTy) == TD.getTypeSize(CTy))
DontPrintWarning = true;
}
}
if (0 && !DontPrintWarning) {
cerr << "WARNING: Found global types that are not compatible:\n";
for (unsigned i = 0; i < Globals.size(); ++i) {
cerr << "\t";
WriteTypeSymbolic(*cerr.stream(), Globals[i]->getType(), &M);
cerr << " %" << Globals[i]->getName() << "\n";
}
}
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));
else
return ResolveGlobalVariables(M, Globals,
cast<GlobalVariable>(Concrete));
}
return false;
}
bool FunctionResolvingPass::runOnModule(Module &M) {
std::map<std::string, std::vector<GlobalValue*> > Globals;
// Loop over the globals, adding them to the Globals map. We use a two pass
// algorithm here to avoid problems with iterators getting invalidated if we
// did a one pass scheme.
//
bool Changed = false;
for (Module::iterator I = M.begin(), E = M.end(); I != E; ) {
Function *F = I++;
if (F->use_empty() && F->isDeclaration()) {
M.getFunctionList().erase(F);
Changed = true;
} else if (!F->hasInternalLinkage() && !F->getName().empty() &&
!F->getIntrinsicID())
Globals[F->getName()].push_back(F);
}
for (Module::global_iterator I = M.global_begin(), E = M.global_end();
I != E; ) {
GlobalVariable *GV = I++;
if (GV->use_empty() && GV->isDeclaration()) {
M.getGlobalList().erase(GV);
Changed = true;
} else if (!GV->hasInternalLinkage() && !GV->getName().empty())
Globals[GV->getName()].push_back(GV);
}
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, TD, I->second);
// Now loop over all of the globals, checking to see if any are trivially
// dead. If so, remove them now.
for (Module::iterator I = M.begin(), E = M.end(); I != E; )
if (I->isDeclaration() && I->use_empty()) {
Function *F = I;
++I;
M.getFunctionList().erase(F);
++NumResolved;
Changed = true;
} else {
++I;
}
for (Module::global_iterator I = M.global_begin(), E = M.global_end();
I != E; )
if (I->isDeclaration() && I->use_empty()) {
GlobalVariable *GV = I;
++I;
M.getGlobalList().erase(GV);
++NumGlobals;
Changed = true;
} else {
++I;
}
return Changed;
}