diff --git a/lib/Transforms/IPO/DeadTypeElimination.cpp b/lib/Transforms/IPO/DeadTypeElimination.cpp index ae7882610b4..5f260a21495 100644 --- a/lib/Transforms/IPO/DeadTypeElimination.cpp +++ b/lib/Transforms/IPO/DeadTypeElimination.cpp @@ -29,8 +29,6 @@ #include static Statistic<> NumTypeSymtabEntriesKilled("cleangcc\t- Number of unused typenames removed from symtab"); -static Statistic<> NumCastsMoved("cleangcc\t- Number of casts removed from head of basic block"); -static Statistic<> NumRefactoredPreds("cleangcc\t- Number of predecessor blocks refactored"); using std::vector; @@ -44,14 +42,15 @@ namespace { // // Also, initialize instance variables. // - bool doInitialization(Module *M); - - // runOnFunction - This method simplifies the specified function hopefully. - // - bool runOnFunction(Function *F); + bool doInitialization(Module &M); + + // FIXME: + // FIXME: This FunctionPass should be a PASS! + // FIXME: + bool runOnFunction(Function &F) { return false; } // doPassFinalization - Strip out type names that are unused by the program - bool doFinalization(Module *M); + bool doFinalization(Module &M); // getAnalysisUsage - This function needs FindUsedTypes to do its job... // @@ -85,12 +84,10 @@ static inline bool ShouldNukeSymtabEntry(const std::pair&E){ // entries for primitive types. These are never used for linking in GCC and // they make the output uglier to look at, so we nuke them. // -bool CleanupGCCOutput::doInitialization(Module *M) { +bool CleanupGCCOutput::doInitialization(Module &M) { bool Changed = false; - if (M->hasSymbolTable()) { - SymbolTable *ST = M->getSymbolTable(); - + if (SymbolTable *ST = M.getSymbolTable()) { // Check the symbol table for superfluous type entries... // // Grab the 'type' plane of the module symbol... @@ -118,183 +115,10 @@ bool CleanupGCCOutput::doInitialization(Module *M) { } -// FixCastsAndPHIs - The LLVM GCC has a tendancy to intermix Cast instructions -// in with the PHI nodes. These cast instructions are potentially there for two -// different reasons: -// -// 1. The cast could be for an early PHI, and be accidentally inserted before -// another PHI node. In this case, the PHI node should be moved to the end -// of the PHI nodes in the basic block. We know that it is this case if -// the source for the cast is a PHI node in this basic block. -// -// 2. If not #1, the cast must be a source argument for one of the PHI nodes -// in the current basic block. If this is the case, the cast should be -// lifted into the basic block for the appropriate predecessor. -// -static inline bool FixCastsAndPHIs(BasicBlock *BB) { +bool CleanupGCCOutput::doFinalization(Module &M) { bool Changed = false; - BasicBlock::iterator InsertPos = BB->begin(); - - // Find the end of the interesting instructions... - while (isa(*InsertPos) || isa(*InsertPos)) ++InsertPos; - - // Back the InsertPos up to right after the last PHI node. - while (InsertPos != BB->begin() && isa(*(InsertPos-1))) --InsertPos; - - // No PHI nodes, quick exit. - if (InsertPos == BB->begin()) return false; - - // Loop over all casts trapped between the PHI's... - BasicBlock::iterator I = BB->begin(); - while (I != InsertPos) { - if (CastInst *CI = dyn_cast(*I)) { // Fix all cast instructions - Value *Src = CI->getOperand(0); - - // Move the cast instruction to the current insert position... - --InsertPos; // New position for cast to go... - std::swap(*InsertPos, *I); // Cast goes down, PHI goes up - Changed = true; - - ++NumCastsMoved; - - if (isa(Src) && // Handle case #1 - cast(Src)->getParent() == BB) { - // We're done for case #1 - } else { // Handle case #2 - // In case #2, we have to do a few things: - // 1. Remove the cast from the current basic block. - // 2. Identify the PHI node that the cast is for. - // 3. Find out which predecessor the value is for. - // 4. Move the cast to the end of the basic block that it SHOULD be - // - - // Remove the cast instruction from the basic block. The remove only - // invalidates iterators in the basic block that are AFTER the removed - // element. Because we just moved the CastInst to the InsertPos, no - // iterators get invalidated. - // - BB->getInstList().remove(InsertPos); - - // Find the PHI node. Since this cast was generated specifically for a - // PHI node, there can only be a single PHI node using it. - // - assert(CI->use_size() == 1 && "Exactly one PHI node should use cast!"); - PHINode *PN = cast(*CI->use_begin()); - - // Find out which operand of the PHI it is... - unsigned i; - for (i = 0; i < PN->getNumIncomingValues(); ++i) - if (PN->getIncomingValue(i) == CI) - break; - assert(i != PN->getNumIncomingValues() && "PHI doesn't use cast!"); - - // Get the predecessor the value is for... - BasicBlock *Pred = PN->getIncomingBlock(i); - - // Reinsert the cast right before the terminator in Pred. - Pred->getInstList().insert(Pred->end()-1, CI); - Changed = true; - } - } else { - ++I; - } - } - - return Changed; -} - -// RefactorPredecessor - When we find out that a basic block is a repeated -// predecessor in a PHI node, we have to refactor the function until there is at -// most a single instance of a basic block in any predecessor list. -// -static inline void RefactorPredecessor(BasicBlock *BB, BasicBlock *Pred) { - Function *M = BB->getParent(); - assert(find(pred_begin(BB), pred_end(BB), Pred) != pred_end(BB) && - "Pred is not a predecessor of BB!"); - - // Create a new basic block, adding it to the end of the function. - BasicBlock *NewBB = new BasicBlock("", M); - - // Add an unconditional branch to BB to the new block. - NewBB->getInstList().push_back(new BranchInst(BB)); - - // Get the terminator that causes a branch to BB from Pred. - TerminatorInst *TI = Pred->getTerminator(); - - // Find the first use of BB in the terminator... - User::op_iterator OI = find(TI->op_begin(), TI->op_end(), BB); - assert(OI != TI->op_end() && "Pred does not branch to BB!!!"); - - // Change the use of BB to point to the new stub basic block - *OI = NewBB; - - // Now we need to loop through all of the PHI nodes in BB and convert their - // first incoming value for Pred to reference the new basic block instead. - // - for (BasicBlock::iterator I = BB->begin(); - PHINode *PN = dyn_cast(*I); ++I) { - int BBIdx = PN->getBasicBlockIndex(Pred); - assert(BBIdx != -1 && "PHI node doesn't have an entry for Pred!"); - - // The value that used to look like it came from Pred now comes from NewBB - PN->setIncomingBlock((unsigned)BBIdx, NewBB); - } -} - - -// runOnFunction - Loop through the function and fix problems with the PHI nodes -// in the current function. The problem is that PHI nodes might exist with -// multiple entries for the same predecessor. GCC sometimes generates code that -// looks like this: -// -// bb7: br bool %cond1004, label %bb8, label %bb8 -// bb8: %reg119 = phi uint [ 0, %bb7 ], [ 1, %bb7 ] -// -// which is completely illegal LLVM code. To compensate for this, we insert -// an extra basic block, and convert the code to look like this: -// -// bb7: br bool %cond1004, label %bbX, label %bb8 -// bbX: br label bb8 -// bb8: %reg119 = phi uint [ 0, %bbX ], [ 1, %bb7 ] -// -// -bool CleanupGCCOutput::runOnFunction(Function *M) { - bool Changed = false; - // Don't use iterators because invalidation gets messy... - for (unsigned MI = 0; MI < M->size(); ++MI) { - BasicBlock *BB = M->getBasicBlocks()[MI]; - - Changed |= FixCastsAndPHIs(BB); - - if (isa(BB->front())) { - const vector Preds(pred_begin(BB), pred_end(BB)); - - // Handle the problem. Sort the list of predecessors so that it is easy - // to decide whether or not duplicate predecessors exist. - vector SortedPreds(Preds); - sort(SortedPreds.begin(), SortedPreds.end()); - - // Loop over the predecessors, looking for adjacent BB's that are equal. - BasicBlock *LastOne = 0; - for (unsigned i = 0; i < Preds.size(); ++i) { - if (SortedPreds[i] == LastOne) { // Found a duplicate. - RefactorPredecessor(BB, SortedPreds[i]); - ++NumRefactoredPreds; - Changed = true; - } - LastOne = SortedPreds[i]; - } - } - } - return Changed; -} - -bool CleanupGCCOutput::doFinalization(Module *M) { - bool Changed = false; - - if (M->hasSymbolTable()) { - SymbolTable *ST = M->getSymbolTable(); + if (SymbolTable *ST = M.getSymbolTable()) { const std::set &UsedTypes = getAnalysis().getTypes();