//===- UnifyFunctionExitNodes.cpp - Make all functions have a single exit -===//
-//
+//
// 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 pass is used to ensure that functions have at most one return
#include "llvm/Function.h"
#include "llvm/Instructions.h"
#include "llvm/Type.h"
+#include "llvm/ADT/StringExtras.h"
using namespace llvm;
-static RegisterOpt<UnifyFunctionExitNodes>
-X("mergereturn", "Unify function exit nodes");
+char UnifyFunctionExitNodes::ID = 0;
+INITIALIZE_PASS(UnifyFunctionExitNodes, "mergereturn",
+ "Unify function exit nodes", false, false)
Pass *llvm::createUnifyFunctionExitNodesPass() {
return new UnifyFunctionExitNodes();
void UnifyFunctionExitNodes::getAnalysisUsage(AnalysisUsage &AU) const{
// We preserve the non-critical-edgeness property
AU.addPreservedID(BreakCriticalEdgesID);
+ // This is a cluster of orthogonal Transforms
+ AU.addPreserved("mem2reg");
+ AU.addPreservedID(LowerSwitchID);
}
// UnifyAllExitNodes - Unify all exit nodes of the CFG by creating a new
// return.
//
std::vector<BasicBlock*> ReturningBlocks;
- std::vector<BasicBlock*> UnwindingBlocks;
std::vector<BasicBlock*> UnreachableBlocks;
for(Function::iterator I = F.begin(), E = F.end(); I != E; ++I)
if (isa<ReturnInst>(I->getTerminator()))
ReturningBlocks.push_back(I);
- else if (isa<UnwindInst>(I->getTerminator()))
- UnwindingBlocks.push_back(I);
else if (isa<UnreachableInst>(I->getTerminator()))
UnreachableBlocks.push_back(I);
- // Handle unwinding blocks first.
- if (UnwindingBlocks.empty()) {
- UnwindBlock = 0;
- } else if (UnwindingBlocks.size() == 1) {
- UnwindBlock = UnwindingBlocks.front();
- } else {
- UnwindBlock = new BasicBlock("UnifiedUnwindBlock", &F);
- new UnwindInst(UnwindBlock);
-
- for (std::vector<BasicBlock*>::iterator I = UnwindingBlocks.begin(),
- E = UnwindingBlocks.end(); I != E; ++I) {
- BasicBlock *BB = *I;
- BB->getInstList().pop_back(); // Remove the unwind insn
- new BranchInst(UnwindBlock, BB);
- }
- }
-
// Then unreachable blocks.
if (UnreachableBlocks.empty()) {
UnreachableBlock = 0;
} else if (UnreachableBlocks.size() == 1) {
UnreachableBlock = UnreachableBlocks.front();
} else {
- UnreachableBlock = new BasicBlock("UnifiedUnreachableBlock", &F);
- new UnreachableInst(UnreachableBlock);
+ UnreachableBlock = BasicBlock::Create(F.getContext(),
+ "UnifiedUnreachableBlock", &F);
+ new UnreachableInst(F.getContext(), UnreachableBlock);
- for (std::vector<BasicBlock*>::iterator I = UnreachableBlocks.begin(),
+ for (std::vector<BasicBlock*>::iterator I = UnreachableBlocks.begin(),
E = UnreachableBlocks.end(); I != E; ++I) {
BasicBlock *BB = *I;
BB->getInstList().pop_back(); // Remove the unreachable inst.
- new BranchInst(UnreachableBlock, BB);
+ BranchInst::Create(UnreachableBlock, BB);
}
}
}
// Otherwise, we need to insert a new basic block into the function, add a PHI
- // node (if the function returns a value), and convert all of the return
+ // nodes (if the function returns values), and convert all of the return
// instructions into unconditional branches.
//
- BasicBlock *NewRetBlock = new BasicBlock("UnifiedReturnBlock", &F);
+ BasicBlock *NewRetBlock = BasicBlock::Create(F.getContext(),
+ "UnifiedReturnBlock", &F);
PHINode *PN = 0;
- if (F.getReturnType() != Type::VoidTy) {
+ if (F.getReturnType()->isVoidTy()) {
+ ReturnInst::Create(F.getContext(), NULL, NewRetBlock);
+ } else {
// If the function doesn't return void... add a PHI node to the block...
- PN = new PHINode(F.getReturnType(), "UnifiedRetVal");
+ PN = PHINode::Create(F.getReturnType(), ReturningBlocks.size(),
+ "UnifiedRetVal");
NewRetBlock->getInstList().push_back(PN);
+ ReturnInst::Create(F.getContext(), PN, NewRetBlock);
}
- new ReturnInst(PN, NewRetBlock);
// Loop over all of the blocks, replacing the return instruction with an
// unconditional branch.
//
- for (std::vector<BasicBlock*>::iterator I = ReturningBlocks.begin(),
+ for (std::vector<BasicBlock*>::iterator I = ReturningBlocks.begin(),
E = ReturningBlocks.end(); I != E; ++I) {
BasicBlock *BB = *I;
// Add an incoming element to the PHI node for every return instruction that
// is merging into this new block...
- if (PN) PN->addIncoming(BB->getTerminator()->getOperand(0), BB);
+ if (PN)
+ PN->addIncoming(BB->getTerminator()->getOperand(0), BB);
BB->getInstList().pop_back(); // Remove the return insn
- new BranchInst(NewRetBlock, BB);
+ BranchInst::Create(NewRetBlock, BB);
}
ReturnBlock = NewRetBlock;
return true;