mirror of
https://github.com/c64scene-ar/llvm-6502.git
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6be5e567ce
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@9366 91177308-0d34-0410-b5e6-96231b3b80d8
303 lines
11 KiB
C++
303 lines
11 KiB
C++
//===- FunctionResolution.cpp - Resolve declarations to implementations ---===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file was developed by the LLVM research group and is distributed under
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// the University of Illinois Open Source License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// Loop over the functions that are in the module and look for functions that
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// have the same name. More often than not, there will be things like:
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//
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// declare void %foo(...)
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// void %foo(int, int) { ... }
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//
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// because of the way things are declared in C. If this is the case, patch
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// things up.
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/Transforms/IPO.h"
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#include "llvm/Module.h"
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#include "llvm/DerivedTypes.h"
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#include "llvm/Pass.h"
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#include "llvm/iOther.h"
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#include "llvm/Constants.h"
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#include "llvm/Target/TargetData.h"
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#include "llvm/Assembly/Writer.h"
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#include "Support/Statistic.h"
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#include <algorithm>
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namespace {
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Statistic<>NumResolved("funcresolve", "Number of varargs functions resolved");
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Statistic<> NumGlobals("funcresolve", "Number of global variables resolved");
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struct FunctionResolvingPass : public Pass {
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virtual void getAnalysisUsage(AnalysisUsage &AU) const {
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AU.addRequired<TargetData>();
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}
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bool run(Module &M);
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};
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RegisterOpt<FunctionResolvingPass> X("funcresolve", "Resolve Functions");
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}
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Pass *createFunctionResolvingPass() {
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return new FunctionResolvingPass();
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}
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static bool ResolveFunctions(Module &M, std::vector<GlobalValue*> &Globals,
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Function *Concrete) {
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bool Changed = false;
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for (unsigned i = 0; i != Globals.size(); ++i)
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if (Globals[i] != Concrete) {
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Function *Old = cast<Function>(Globals[i]);
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const FunctionType *OldMT = Old->getFunctionType();
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const FunctionType *ConcreteMT = Concrete->getFunctionType();
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if (OldMT->getParamTypes().size() > ConcreteMT->getParamTypes().size() &&
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!ConcreteMT->isVarArg())
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if (!Old->use_empty()) {
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std::cerr << "WARNING: Linking function '" << Old->getName()
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<< "' is causing arguments to be dropped.\n";
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std::cerr << "WARNING: Prototype: ";
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WriteAsOperand(std::cerr, Old);
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std::cerr << " resolved to ";
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WriteAsOperand(std::cerr, Concrete);
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std::cerr << "\n";
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}
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// Check to make sure that if there are specified types, that they
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// match...
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//
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unsigned NumArguments = std::min(OldMT->getParamTypes().size(),
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ConcreteMT->getParamTypes().size());
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if (!Old->use_empty() && !Concrete->use_empty())
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for (unsigned i = 0; i < NumArguments; ++i)
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if (OldMT->getParamTypes()[i] != ConcreteMT->getParamTypes()[i])
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if (OldMT->getParamTypes()[i]->getPrimitiveID() !=
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ConcreteMT->getParamTypes()[i]->getPrimitiveID()) {
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std::cerr << "WARNING: Function [" << Old->getName()
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<< "]: Parameter types conflict for: '" << OldMT
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<< "' and '" << ConcreteMT << "'\n";
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return Changed;
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}
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// Attempt to convert all of the uses of the old function to the concrete
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// form of the function. If there is a use of the fn that we don't
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// understand here we punt to avoid making a bad transformation.
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//
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// At this point, we know that the return values are the same for our two
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// functions and that the Old function has no varargs fns specified. In
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// otherwords it's just <retty> (...)
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//
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if (!Old->use_empty()) { // Avoid making the CPR unless we really need it
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Value *Replacement = Concrete;
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if (Concrete->getType() != Old->getType())
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Replacement = ConstantExpr::getCast(ConstantPointerRef::get(Concrete),
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Old->getType());
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NumResolved += Old->use_size();
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Old->replaceAllUsesWith(Replacement);
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}
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// Since there are no uses of Old anymore, remove it from the module.
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M.getFunctionList().erase(Old);
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}
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return Changed;
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}
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static bool ResolveGlobalVariables(Module &M,
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std::vector<GlobalValue*> &Globals,
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GlobalVariable *Concrete) {
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bool Changed = false;
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Constant *CCPR = ConstantPointerRef::get(Concrete);
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for (unsigned i = 0; i != Globals.size(); ++i)
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if (Globals[i] != Concrete) {
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Constant *Cast = ConstantExpr::getCast(CCPR, Globals[i]->getType());
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Globals[i]->replaceAllUsesWith(Cast);
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// Since there are no uses of Old anymore, remove it from the module.
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M.getGlobalList().erase(cast<GlobalVariable>(Globals[i]));
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++NumGlobals;
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Changed = true;
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}
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return Changed;
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}
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static bool ProcessGlobalsWithSameName(Module &M, TargetData &TD,
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std::vector<GlobalValue*> &Globals) {
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assert(!Globals.empty() && "Globals list shouldn't be empty here!");
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bool isFunction = isa<Function>(Globals[0]); // Is this group all functions?
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GlobalValue *Concrete = 0; // The most concrete implementation to resolve to
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for (unsigned i = 0; i != Globals.size(); ) {
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if (isa<Function>(Globals[i]) != isFunction) {
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std::cerr << "WARNING: Found function and global variable with the "
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<< "same name: '" << Globals[i]->getName() << "'.\n";
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return false; // Don't know how to handle this, bail out!
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}
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if (isFunction) {
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// For functions, we look to merge functions definitions of "int (...)"
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// to 'int (int)' or 'int ()' or whatever else is not completely generic.
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//
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Function *F = cast<Function>(Globals[i]);
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if (!F->isExternal()) {
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if (Concrete && !Concrete->isExternal())
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return false; // Found two different functions types. Can't choose!
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Concrete = Globals[i];
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} else if (Concrete) {
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if (Concrete->isExternal()) // If we have multiple external symbols...x
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if (F->getFunctionType()->getNumParams() >
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cast<Function>(Concrete)->getFunctionType()->getNumParams())
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Concrete = F; // We are more concrete than "Concrete"!
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} else {
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Concrete = F;
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}
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} else {
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GlobalVariable *GV = cast<GlobalVariable>(Globals[i]);
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if (!GV->isExternal()) {
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if (Concrete) {
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std::cerr << "WARNING: Two global variables with external linkage"
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<< " exist with the same name: '" << GV->getName()
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<< "'!\n";
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return false;
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}
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Concrete = GV;
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}
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}
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++i;
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}
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if (Globals.size() > 1) { // Found a multiply defined global...
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// If there are no external declarations, and there is at most one
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// externally visible instance of the global, then there is nothing to do.
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//
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bool HasExternal = false;
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unsigned NumInstancesWithExternalLinkage = 0;
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for (unsigned i = 0, e = Globals.size(); i != e; ++i) {
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if (Globals[i]->isExternal())
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HasExternal = true;
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else if (!Globals[i]->hasInternalLinkage())
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NumInstancesWithExternalLinkage++;
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}
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if (!HasExternal && NumInstancesWithExternalLinkage <= 1)
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return false; // Nothing to do? Must have multiple internal definitions.
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std::cerr << "WARNING: Found global types that are not compatible:\n";
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for (unsigned i = 0; i < Globals.size(); ++i) {
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std::cerr << "\t" << *Globals[i]->getType() << " %"
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<< Globals[i]->getName() << "\n";
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}
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if (!Concrete)
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Concrete = Globals[0];
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else if (GlobalVariable *GV = dyn_cast<GlobalVariable>(Concrete)) {
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// Handle special case hack to change globals if it will make their types
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// happier in the long run. The situation we do this is intentionally
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// extremely limited.
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if (GV->use_empty() && GV->hasInitializer() &&
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GV->getInitializer()->isNullValue()) {
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// Check to see if there is another (external) global with the same size
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// and a non-empty use-list. If so, we will make IT be the real
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// implementation.
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unsigned TS = TD.getTypeSize(Concrete->getType()->getElementType());
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for (unsigned i = 0, e = Globals.size(); i != e; ++i)
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if (Globals[i] != Concrete && !Globals[i]->use_empty() &&
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isa<GlobalVariable>(Globals[i]) &&
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TD.getTypeSize(Globals[i]->getType()->getElementType()) == TS) {
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// At this point we want to replace Concrete with Globals[i]. Make
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// concrete external, and Globals[i] have an initializer.
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GlobalVariable *NGV = cast<GlobalVariable>(Globals[i]);
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const Type *ElTy = NGV->getType()->getElementType();
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NGV->setInitializer(Constant::getNullValue(ElTy));
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cast<GlobalVariable>(Concrete)->setInitializer(0);
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Concrete = NGV;
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break;
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}
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}
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}
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if (isFunction)
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return ResolveFunctions(M, Globals, cast<Function>(Concrete));
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else
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return ResolveGlobalVariables(M, Globals,
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cast<GlobalVariable>(Concrete));
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}
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return false;
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}
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bool FunctionResolvingPass::run(Module &M) {
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std::map<std::string, std::vector<GlobalValue*> > Globals;
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// Loop over the globals, adding them to the Globals map. We use a two pass
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// algorithm here to avoid problems with iterators getting invalidated if we
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// did a one pass scheme.
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//
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bool Changed = false;
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for (Module::iterator I = M.begin(), E = M.end(); I != E; ) {
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Function *F = I++;
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if (F->use_empty() && F->isExternal()) {
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M.getFunctionList().erase(F);
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Changed = true;
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} else if (!F->hasInternalLinkage() && !F->getName().empty())
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Globals[F->getName()].push_back(F);
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}
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for (Module::giterator I = M.gbegin(), E = M.gend(); I != E; ) {
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GlobalVariable *GV = I++;
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if (GV->use_empty() && GV->isExternal()) {
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M.getGlobalList().erase(GV);
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Changed = true;
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} else if (!GV->hasInternalLinkage() && !GV->getName().empty())
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Globals[GV->getName()].push_back(GV);
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}
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TargetData &TD = getAnalysis<TargetData>();
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// Now we have a list of all functions with a particular name. If there is
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// more than one entry in a list, merge the functions together.
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//
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for (std::map<std::string, std::vector<GlobalValue*> >::iterator
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I = Globals.begin(), E = Globals.end(); I != E; ++I)
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Changed |= ProcessGlobalsWithSameName(M, TD, I->second);
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// Now loop over all of the globals, checking to see if any are trivially
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// dead. If so, remove them now.
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for (Module::iterator I = M.begin(), E = M.end(); I != E; )
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if (I->isExternal() && I->use_empty()) {
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Function *F = I;
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++I;
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M.getFunctionList().erase(F);
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++NumResolved;
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Changed = true;
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} else {
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++I;
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}
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for (Module::giterator I = M.gbegin(), E = M.gend(); I != E; )
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if (I->isExternal() && I->use_empty()) {
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GlobalVariable *GV = I;
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++I;
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M.getGlobalList().erase(GV);
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++NumGlobals;
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Changed = true;
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} else {
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++I;
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}
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return Changed;
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}
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