mirror of
https://github.com/c64scene-ar/llvm-6502.git
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a45ec54a02
and global variables. This fixes bug: FuncResolve/2002-08-19-ResolveGlobalVarsEasier.ll And bug: SingleSource/UnitTests/2002-10-09-ArrayResolution.c Note that this does not fix bug: FunctionResolve/2002-08-19-ResolveGlobalVars.ll because replaceAllUsesWith breaks when a constantexpr is pointing to the thing being replaced. This is more of an infrastructure problem than anything. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@4099 91177308-0d34-0410-b5e6-96231b3b80d8
346 lines
12 KiB
C++
346 lines
12 KiB
C++
//===- FunctionResolution.cpp - Resolve declarations to implementations ---===//
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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/SymbolTable.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 "Support/Statistic.h"
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#include <algorithm>
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using std::vector;
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using std::string;
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using std::cerr;
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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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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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// ConvertCallTo - Convert a call to a varargs function with no arg types
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// specified to a concrete nonvarargs function.
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//
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static void ConvertCallTo(CallInst *CI, Function *Dest) {
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const FunctionType::ParamTypes &ParamTys =
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Dest->getFunctionType()->getParamTypes();
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BasicBlock *BB = CI->getParent();
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// Keep an iterator to where we want to insert cast instructions if the
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// argument types don't agree.
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//
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BasicBlock::iterator BBI = CI;
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assert(CI->getNumOperands()-1 == ParamTys.size() &&
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"Function calls resolved funny somehow, incompatible number of args");
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vector<Value*> Params;
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// Convert all of the call arguments over... inserting cast instructions if
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// the types are not compatible.
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for (unsigned i = 1; i < CI->getNumOperands(); ++i) {
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Value *V = CI->getOperand(i);
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if (V->getType() != ParamTys[i-1]) // Must insert a cast...
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V = new CastInst(V, ParamTys[i-1], "argcast", BBI);
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Params.push_back(V);
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}
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// Replace the old call instruction with a new call instruction that calls
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// the real function.
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//
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Instruction *NewCall = new CallInst(Dest, Params, "", BBI);
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// Remove the old call instruction from the program...
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BB->getInstList().remove(BBI);
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// Transfer the name over...
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if (NewCall->getType() != Type::VoidTy)
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NewCall->setName(CI->getName());
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// Replace uses of the old instruction with the appropriate values...
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//
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if (NewCall->getType() == CI->getType()) {
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CI->replaceAllUsesWith(NewCall);
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NewCall->setName(CI->getName());
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} else if (NewCall->getType() == Type::VoidTy) {
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// Resolved function does not return a value but the prototype does. This
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// often occurs because undefined functions default to returning integers.
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// Just replace uses of the call (which are broken anyway) with dummy
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// values.
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CI->replaceAllUsesWith(Constant::getNullValue(CI->getType()));
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} else if (CI->getType() == Type::VoidTy) {
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// If we are gaining a new return value, we don't have to do anything
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// special here, because it will automatically be ignored.
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} else {
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// Insert a cast instruction to convert the return value of the function
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// into it's new type. Of course we only need to do this if the return
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// value of the function is actually USED.
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//
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if (!CI->use_empty()) {
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// Insert the new cast instruction...
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CastInst *NewCast = new CastInst(NewCall, CI->getType(),
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NewCall->getName(), BBI);
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CI->replaceAllUsesWith(NewCast);
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}
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}
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// The old instruction is no longer needed, destroy it!
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delete CI;
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}
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static bool ResolveFunctions(Module &M, 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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assert(OldMT->getParamTypes().size() <=
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ConcreteMT->getParamTypes().size() &&
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"Concrete type must have more specified parameters!");
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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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for (unsigned i = 0; i < OldMT->getParamTypes().size(); ++i)
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if (OldMT->getParamTypes()[i] != ConcreteMT->getParamTypes()[i]) {
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cerr << "Parameter types conflict for" << OldMT
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<< " and " << ConcreteMT;
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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
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// concrete form of the function. If there is a use of the fn that
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// we don't understand here we punt to avoid making a bad
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// transformation.
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//
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// At this point, we know that the return values are the same for
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// our two functions and that the Old function has no varargs fns
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// specified. In otherwords it's just <retty> (...)
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//
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for (unsigned i = 0; i < Old->use_size(); ) {
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User *U = *(Old->use_begin()+i);
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if (CastInst *CI = dyn_cast<CastInst>(U)) {
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// Convert casts directly
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assert(CI->getOperand(0) == Old);
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CI->setOperand(0, Concrete);
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Changed = true;
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++NumResolved;
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} else if (CallInst *CI = dyn_cast<CallInst>(U)) {
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// Can only fix up calls TO the argument, not args passed in.
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if (CI->getCalledValue() == Old) {
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ConvertCallTo(CI, Concrete);
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Changed = true;
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++NumResolved;
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} else {
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cerr << "Couldn't cleanup this function call, must be an"
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<< " argument or something!" << CI;
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++i;
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}
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} else {
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cerr << "Cannot convert use of function: " << U << "\n";
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++i;
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}
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}
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}
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return Changed;
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}
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static bool ResolveGlobalVariables(Module &M, vector<GlobalValue*> &Globals,
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GlobalVariable *Concrete) {
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bool Changed = false;
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assert(isa<ArrayType>(Concrete->getType()->getElementType()) &&
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"Concrete version should be an array type!");
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// Get the type of the things that may be resolved to us...
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const Type *AETy =
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cast<ArrayType>(Concrete->getType()->getElementType())->getElementType();
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std::vector<Constant*> Args;
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Args.push_back(Constant::getNullValue(Type::LongTy));
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Args.push_back(Constant::getNullValue(Type::LongTy));
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ConstantExpr *Replacement =
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ConstantExpr::getGetElementPtr(ConstantPointerRef::get(Concrete), Args);
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for (unsigned i = 0; i != Globals.size(); ++i)
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if (Globals[i] != Concrete) {
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GlobalVariable *Old = cast<GlobalVariable>(Globals[i]);
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if (Old->getType()->getElementType() != AETy) {
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std::cerr << "WARNING: Two global variables exist with the same name "
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<< "that cannot be resolved!\n";
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return false;
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}
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// In this case, Old is a pointer to T, Concrete is a pointer to array of
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// T. Because of this, replace all uses of Old with a constantexpr
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// getelementptr that returns the address of the first element of the
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// array.
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//
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Old->replaceAllUsesWith(Replacement);
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// Since there are no uses of Old anymore, remove it from the module.
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M.getGlobalList().erase(Old);
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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,
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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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bool Changed = false;
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GlobalValue *Concrete = 0; // The most concrete implementation to resolve to
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assert((isFunction ^ isa<GlobalVariable>(Globals[0])) &&
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"Should either be function or gvar!");
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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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// Ignore globals that are never used so they don't cause spurious
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// warnings... here we will actually DCE the function so that it isn't used
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// later.
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//
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if (Globals[i]->isExternal() && Globals[i]->use_empty()) {
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if (isFunction)
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M.getFunctionList().erase(cast<Function>(Globals[i]));
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else
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M.getGlobalList().erase(cast<GlobalVariable>(Globals[i]));
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Globals.erase(Globals.begin()+i);
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Changed = true;
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++NumResolved;
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} else 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->getFunctionType()->isVarArg() ||
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F->getFunctionType()->getNumParams()) {
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if (Concrete)
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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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}
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++i;
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} else {
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// For global variables, we have to merge C definitions int A[][4] with
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// int[6][4]
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GlobalVariable *GV = cast<GlobalVariable>(Globals[i]);
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if (Concrete == 0) {
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if (isa<ArrayType>(GV->getType()->getElementType()))
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Concrete = GV;
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} else { // Must have different types... one is an array of the other?
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const ArrayType *AT =
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dyn_cast<ArrayType>(GV->getType()->getElementType());
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// If GV is an array of Concrete, then GV is the array.
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if (AT && AT->getElementType() == Concrete->getType()->getElementType())
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Concrete = GV;
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else {
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// Concrete must be an array type, check to see if the element type of
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// concrete is already GV.
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AT = cast<ArrayType>(Concrete->getType()->getElementType());
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if (AT->getElementType() != GV->getType()->getElementType())
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Concrete = 0; // Don't know how to handle it!
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}
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}
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++i;
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}
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}
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if (Globals.size() > 1) { // Found a multiply defined global...
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// We should find exactly one concrete function definition, which is
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// probably the implementation. Change all of the function definitions and
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// uses to use it instead.
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//
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if (!Concrete) {
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cerr << "WARNING: Found function types that are not compatible:\n";
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for (unsigned i = 0; i < Globals.size(); ++i) {
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cerr << "\t" << Globals[i]->getType()->getDescription() << " %"
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<< Globals[i]->getName() << "\n";
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}
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cerr << " No linkage of globals named '" << Globals[0]->getName()
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<< "' performed!\n";
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return Changed;
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}
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if (isFunction)
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return Changed | ResolveFunctions(M, Globals, cast<Function>(Concrete));
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else
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return Changed | ResolveGlobalVariables(M, Globals,
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cast<GlobalVariable>(Concrete));
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}
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return Changed;
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}
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bool FunctionResolvingPass::run(Module &M) {
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SymbolTable *ST = M.getSymbolTable();
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if (!ST) return false;
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std::map<string, vector<GlobalValue*> > Globals;
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// Loop over the entries in the symbol table. If an entry is a func pointer,
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// then add it to the Functions map. We do a two pass algorithm here to avoid
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// problems with iterators getting invalidated if we did a one pass scheme.
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//
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for (SymbolTable::iterator I = ST->begin(), E = ST->end(); I != E; ++I)
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if (const PointerType *PT = dyn_cast<PointerType>(I->first)) {
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SymbolTable::VarMap &Plane = I->second;
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for (SymbolTable::type_iterator PI = Plane.begin(), PE = Plane.end();
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PI != PE; ++PI) {
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GlobalValue *GV = cast<GlobalValue>(PI->second);
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assert(PI->first == GV->getName() &&
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"Global name and symbol table do not agree!");
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if (GV->hasExternalLinkage()) // Only resolve decls to external fns
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Globals[PI->first].push_back(GV);
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}
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}
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bool Changed = false;
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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<string, vector<GlobalValue*> >::iterator I = Globals.begin(),
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E = Globals.end(); I != E; ++I)
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Changed |= ProcessGlobalsWithSameName(M, I->second);
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return Changed;
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}
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