//
// 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.
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
-// This file demotes all registers to memory references. It is intented to be
+// This file demotes all registers to memory references. It is intended to be
// the inverse of PromoteMemoryToRegister. By converting to loads, the only
-// values live accross basic blocks are allocas and loads before phi nodes.
+// values live across basic blocks are allocas and loads before phi nodes.
// It is intended that this should make CFG hacking much easier.
// To make later hacking easier, the entry block is split into two, such that
// all introduced allocas and nothing else are in the entry block.
//
//===----------------------------------------------------------------------===//
-#define DEBUG_TYPE "reg2mem"
#include "llvm/Transforms/Scalar.h"
-#include "llvm/Transforms/Utils/Local.h"
-#include "llvm/Pass.h"
-#include "llvm/Function.h"
-#include "llvm/Module.h"
-#include "llvm/BasicBlock.h"
-#include "llvm/Instructions.h"
#include "llvm/ADT/Statistic.h"
+#include "llvm/IR/BasicBlock.h"
+#include "llvm/IR/CFG.h"
+#include "llvm/IR/Function.h"
+#include "llvm/IR/Instructions.h"
+#include "llvm/IR/LLVMContext.h"
+#include "llvm/IR/Module.h"
+#include "llvm/Pass.h"
+#include "llvm/Transforms/Utils/Local.h"
#include <list>
using namespace llvm;
-STATISTIC(NumDemoted, "Number of registers demoted");
+#define DEBUG_TYPE "reg2mem"
+
+STATISTIC(NumRegsDemoted, "Number of registers demoted");
+STATISTIC(NumPhisDemoted, "Number of phi-nodes demoted");
namespace {
struct RegToMem : public FunctionPass {
+ static char ID; // Pass identification, replacement for typeid
+ RegToMem() : FunctionPass(ID) {
+ initializeRegToMemPass(*PassRegistry::getPassRegistry());
+ }
- virtual void getAnalysisUsage(AnalysisUsage &AU) const {
+ void getAnalysisUsage(AnalysisUsage &AU) const override {
AU.addRequiredID(BreakCriticalEdgesID);
AU.addPreservedID(BreakCriticalEdgesID);
}
- bool valueEscapes(Instruction* i) {
- BasicBlock* bb = i->getParent();
- for(Value::use_iterator ii = i->use_begin(), ie = i->use_end();
- ii != ie; ++ii)
- if (cast<Instruction>(*ii)->getParent() != bb ||
- isa<PHINode>(*ii))
+ bool valueEscapes(const Instruction *Inst) const {
+ const BasicBlock *BB = Inst->getParent();
+ for (const User *U : Inst->users()) {
+ const Instruction *UI = cast<Instruction>(U);
+ if (UI->getParent() != BB || isa<PHINode>(UI))
return true;
+ }
return false;
}
- virtual bool runOnFunction(Function &F) {
- if (!F.isExternal()) {
- //give us a clean block
- BasicBlock* bbold = &F.getEntryBlock();
- BasicBlock* bbnew = new BasicBlock("allocablock", &F, &F.getEntryBlock());
- new BranchInst(bbold, bbnew);
-
- //find the instructions
- std::list<Instruction*> worklist;
- for (Function::iterator ibb = F.begin(), ibe = F.end();
- ibb != ibe; ++ibb)
- for (BasicBlock::iterator iib = ibb->begin(), iie = ibb->end();
- iib != iie; ++iib) {
- if(valueEscapes(iib))
- worklist.push_front(&*iib);
- }
- //demote escaped instructions
- NumDemoted += worklist.size();
- for (std::list<Instruction*>::iterator ilb = worklist.begin(),
- ile = worklist.end(); ilb != ile; ++ilb)
- DemoteRegToStack(**ilb, false);
- return true;
+ bool runOnFunction(Function &F) override;
+ };
+} // namespace
+
+char RegToMem::ID = 0;
+INITIALIZE_PASS_BEGIN(RegToMem, "reg2mem", "Demote all values to stack slots",
+ false, false)
+INITIALIZE_PASS_DEPENDENCY(BreakCriticalEdges)
+INITIALIZE_PASS_END(RegToMem, "reg2mem", "Demote all values to stack slots",
+ false, false)
+
+bool RegToMem::runOnFunction(Function &F) {
+ if (F.isDeclaration())
+ return false;
+
+ // Insert all new allocas into entry block.
+ BasicBlock *BBEntry = &F.getEntryBlock();
+ assert(pred_empty(BBEntry) &&
+ "Entry block to function must not have predecessors!");
+
+ // Find first non-alloca instruction and create insertion point. This is
+ // safe if block is well-formed: it always have terminator, otherwise
+ // we'll get and assertion.
+ BasicBlock::iterator I = BBEntry->begin();
+ while (isa<AllocaInst>(I)) ++I;
+
+ CastInst *AllocaInsertionPoint =
+ new BitCastInst(Constant::getNullValue(Type::getInt32Ty(F.getContext())),
+ Type::getInt32Ty(F.getContext()),
+ "reg2mem alloca point", I);
+
+ // Find the escaped instructions. But don't create stack slots for
+ // allocas in entry block.
+ std::list<Instruction*> WorkList;
+ for (Function::iterator ibb = F.begin(), ibe = F.end();
+ ibb != ibe; ++ibb)
+ for (BasicBlock::iterator iib = ibb->begin(), iie = ibb->end();
+ iib != iie; ++iib) {
+ if (!(isa<AllocaInst>(iib) && iib->getParent() == BBEntry) &&
+ valueEscapes(iib)) {
+ WorkList.push_front(&*iib);
}
- return false;
}
- };
-
- RegisterPass<RegToMem> X("reg2mem", "Demote all values to stack slots");
+
+ // Demote escaped instructions
+ NumRegsDemoted += WorkList.size();
+ for (std::list<Instruction*>::iterator ilb = WorkList.begin(),
+ ile = WorkList.end(); ilb != ile; ++ilb)
+ DemoteRegToStack(**ilb, false, AllocaInsertionPoint);
+
+ WorkList.clear();
+
+ // Find all phi's
+ for (Function::iterator ibb = F.begin(), ibe = F.end();
+ ibb != ibe; ++ibb)
+ for (BasicBlock::iterator iib = ibb->begin(), iie = ibb->end();
+ iib != iie; ++iib)
+ if (isa<PHINode>(iib))
+ WorkList.push_front(&*iib);
+
+ // Demote phi nodes
+ NumPhisDemoted += WorkList.size();
+ for (std::list<Instruction*>::iterator ilb = WorkList.begin(),
+ ile = WorkList.end(); ilb != ile; ++ilb)
+ DemotePHIToStack(cast<PHINode>(*ilb), AllocaInsertionPoint);
+
+ return true;
}
+
// createDemoteRegisterToMemory - Provide an entry point to create this pass.
-//
-const PassInfo *llvm::DemoteRegisterToMemoryID = X.getPassInfo();
+char &llvm::DemoteRegisterToMemoryID = RegToMem::ID;
FunctionPass *llvm::createDemoteRegisterToMemoryPass() {
return new RegToMem();
}
projects / oota-llvm.git / blobdiff