Split the FunctionResolution pass out of CleanGCCOutput.cpp.
llvm-svn: 2742
diff --git a/llvm/lib/Transforms/IPO/FunctionResolution.cpp b/llvm/lib/Transforms/IPO/FunctionResolution.cpp
new file mode 100644
index 0000000..63ea3b1
--- /dev/null
+++ b/llvm/lib/Transforms/IPO/FunctionResolution.cpp
@@ -0,0 +1,223 @@
+//===- FunctionResolution.cpp - Resolve declarations to implementations ---===//
+//
+// 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.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Transforms/CleanupGCCOutput.h"
+#include "llvm/Module.h"
+#include "llvm/Function.h"
+#include "llvm/Transforms/Utils/BasicBlockUtils.h"
+#include "llvm/SymbolTable.h"
+#include "llvm/DerivedTypes.h"
+#include "llvm/Pass.h"
+#include "llvm/iOther.h"
+#include "Support/StatisticReporter.h"
+#include <iostream>
+#include <algorithm>
+
+using std::vector;
+using std::string;
+using std::cerr;
+
+namespace {
+ Statistic<>NumResolved("funcresolve\t- Number of varargs functions resolved");
+
+ struct FunctionResolvingPass : public Pass {
+ const char *getPassName() const { return "Resolve Functions"; }
+
+ bool run(Module *M);
+ };
+}
+
+Pass *createFunctionResolvingPass() {
+ return new FunctionResolvingPass();
+}
+
+// ConvertCallTo - Convert a call to a varargs function with no arg types
+// specified to a concrete nonvarargs function.
+//
+static void ConvertCallTo(CallInst *CI, Function *Dest) {
+ const FunctionType::ParamTypes &ParamTys =
+ Dest->getFunctionType()->getParamTypes();
+ BasicBlock *BB = CI->getParent();
+
+ // Get an iterator to where we want to insert cast instructions if the
+ // argument types don't agree.
+ //
+ BasicBlock::iterator BBI = find(BB->begin(), BB->end(), CI);
+ assert(BBI != BB->end() && "CallInst not in parent block?");
+
+ assert(CI->getNumOperands()-1 == ParamTys.size()&&
+ "Function calls resolved funny somehow, incompatible number of args");
+
+ vector<Value*> Params;
+
+ // Convert all of the call arguments over... inserting cast instructions if
+ // the types are not compatible.
+ for (unsigned i = 1; i < CI->getNumOperands(); ++i) {
+ Value *V = CI->getOperand(i);
+
+ if (V->getType() != ParamTys[i-1]) { // Must insert a cast...
+ Instruction *Cast = new CastInst(V, ParamTys[i-1]);
+ BBI = BB->getInstList().insert(BBI, Cast)+1;
+ V = Cast;
+ }
+
+ Params.push_back(V);
+ }
+
+ // Replace the old call instruction with a new call instruction that calls
+ // the real function.
+ //
+ ReplaceInstWithInst(BB->getInstList(), BBI, new CallInst(Dest, Params));
+}
+
+
+bool FunctionResolvingPass::run(Module *M) {
+ SymbolTable *ST = M->getSymbolTable();
+ if (!ST) return false;
+
+ std::map<string, vector<Function*> > Functions;
+
+ // Loop over the entries in the symbol table. If an entry is a func pointer,
+ // then add it to the Functions map. We do a two pass algorithm here to avoid
+ // problems with iterators getting invalidated if we did a one pass scheme.
+ //
+ for (SymbolTable::iterator I = ST->begin(), E = ST->end(); I != E; ++I)
+ if (const PointerType *PT = dyn_cast<PointerType>(I->first))
+ if (isa<FunctionType>(PT->getElementType())) {
+ SymbolTable::VarMap &Plane = I->second;
+ for (SymbolTable::type_iterator PI = Plane.begin(), PE = Plane.end();
+ PI != PE; ++PI) {
+ const string &Name = PI->first;
+ Functions[Name].push_back(cast<Function>(PI->second));
+ }
+ }
+
+ bool Changed = false;
+
+ // 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<string, vector<Function*> >::iterator I = Functions.begin(),
+ E = Functions.end(); I != E; ++I) {
+ vector<Function*> &Functions = I->second;
+ Function *Implementation = 0; // Find the implementation
+ Function *Concrete = 0;
+ for (unsigned i = 0; i < Functions.size(); ) {
+ if (!Functions[i]->isExternal()) { // Found an implementation
+ assert(Implementation == 0 && "Multiple definitions of the same"
+ " function. Case not handled yet!");
+ Implementation = Functions[i];
+ } else {
+ // Ignore functions that are never used so they don't cause spurious
+ // warnings... here we will actually DCE the function so that it isn't
+ // used later.
+ //
+ if (Functions[i]->use_size() == 0) {
+ M->getFunctionList().remove(Functions[i]);
+ delete Functions[i];
+ Functions.erase(Functions.begin()+i);
+ Changed = true;
+ ++NumResolved;
+ continue;
+ }
+ }
+
+ if (Functions[i] && (!Functions[i]->getFunctionType()->isVarArg())) {
+ if (Concrete) { // Found two different functions types. Can't choose
+ Concrete = 0;
+ break;
+ }
+ Concrete = Functions[i];
+ }
+ ++i;
+ }
+
+ if (Functions.size() > 1) { // Found a multiply defined function...
+ // We should find exactly one non-vararg function definition, which is
+ // probably the implementation. Change all of the function definitions
+ // and uses to use it instead.
+ //
+ if (!Concrete) {
+ cerr << "Warning: Found functions types that are not compatible:\n";
+ for (unsigned i = 0; i < Functions.size(); ++i) {
+ cerr << "\t" << Functions[i]->getType()->getDescription() << " %"
+ << Functions[i]->getName() << "\n";
+ }
+ cerr << " No linkage of functions named '" << Functions[0]->getName()
+ << "' performed!\n";
+ } else {
+ for (unsigned i = 0; i < Functions.size(); ++i)
+ if (Functions[i] != Concrete) {
+ Function *Old = Functions[i];
+ const FunctionType *OldMT = Old->getFunctionType();
+ const FunctionType *ConcreteMT = Concrete->getFunctionType();
+ bool Broken = false;
+
+ assert(Old->getReturnType() == Concrete->getReturnType() &&
+ "Differing return types not handled yet!");
+ assert(OldMT->getParamTypes().size() <=
+ ConcreteMT->getParamTypes().size() &&
+ "Concrete type must have more specified parameters!");
+
+ // Check to make sure that if there are specified types, that they
+ // match...
+ //
+ for (unsigned i = 0; i < OldMT->getParamTypes().size(); ++i)
+ if (OldMT->getParamTypes()[i] != ConcreteMT->getParamTypes()[i]) {
+ cerr << "Parameter types conflict for" << OldMT
+ << " and " << ConcreteMT;
+ Broken = true;
+ }
+ if (Broken) break; // Can't process this one!
+
+
+ // 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> (...)
+ //
+ for (unsigned i = 0; i < Old->use_size(); ) {
+ User *U = *(Old->use_begin()+i);
+ if (CastInst *CI = dyn_cast<CastInst>(U)) {
+ // Convert casts directly
+ assert(CI->getOperand(0) == Old);
+ CI->setOperand(0, Concrete);
+ Changed = true;
+ ++NumResolved;
+ } else if (CallInst *CI = dyn_cast<CallInst>(U)) {
+ // Can only fix up calls TO the argument, not args passed in.
+ if (CI->getCalledValue() == Old) {
+ ConvertCallTo(CI, Concrete);
+ Changed = true;
+ ++NumResolved;
+ } else {
+ cerr << "Couldn't cleanup this function call, must be an"
+ << " argument or something!" << CI;
+ ++i;
+ }
+ } else {
+ cerr << "Cannot convert use of function: " << U << "\n";
+ ++i;
+ }
+ }
+ }
+ }
+ }
+ }
+
+ return Changed;
+}