//===- UnifyFunctionExitNodes.cpp - Make all functions have a single exit -===//
//
-// This file provides several routines that are useful for simplifying CFGs in
-// various ways...
+// This pass is used to ensure that functions have at most one return
+// instruction in them. Additionally, it keeps track of which node is the new
+// exit node of the CFG. If there are no exit nodes in the CFG, the getExitNode
+// method will return a null pointer.
//
//===----------------------------------------------------------------------===//
-#include "llvm/Transforms/UnifyFunctionExitNodes.h"
+#include "llvm/Transforms/Utils/UnifyFunctionExitNodes.h"
#include "llvm/BasicBlock.h"
#include "llvm/Function.h"
#include "llvm/iTerminators.h"
#include "llvm/Type.h"
using std::vector;
-AnalysisID UnifyFunctionExitNodes::ID(AnalysisID::create<UnifyFunctionExitNodes>());
-
+static RegisterOpt<UnifyFunctionExitNodes>
+X("mergereturn", "Unify function exit nodes");
// UnifyAllExitNodes - Unify all exit nodes of the CFG by creating a new
// BasicBlock, and converting all returns to unconditional branches to this
//
// If there are no return stmts in the Function, a null pointer is returned.
//
-bool UnifyFunctionExitNodes::doit(Function *M, BasicBlock *&ExitNode) {
+bool UnifyFunctionExitNodes::runOnFunction(Function &F) {
// Loop over all of the blocks in a function, tracking all of the blocks that
// return.
//
vector<BasicBlock*> ReturningBlocks;
- for(Function::iterator I = M->begin(), E = M->end(); I != E; ++I)
- if (isa<ReturnInst>((*I)->getTerminator()))
- ReturningBlocks.push_back(*I);
+ for(Function::iterator I = F.begin(), E = F.end(); I != E; ++I)
+ if (isa<ReturnInst>(I->getTerminator()))
+ ReturningBlocks.push_back(I);
if (ReturningBlocks.empty()) {
ExitNode = 0;
- return false; // No blocks return
+ return false; // No blocks return
} else if (ReturningBlocks.size() == 1) {
ExitNode = ReturningBlocks.front(); // Already has a single return block
return false;
// node (if the function returns a value), and convert all of the return
// instructions into unconditional branches.
//
- BasicBlock *NewRetBlock = new BasicBlock("UnifiedExitNode", M);
+ BasicBlock *NewRetBlock = new BasicBlock("UnifiedExitNode", &F);
- if (M->getReturnType() != Type::VoidTy) {
+ if (F.getReturnType() != Type::VoidTy) {
// If the function doesn't return void... add a PHI node to the block...
- PHINode *PN = new PHINode(M->getReturnType());
+ PHINode *PN = new PHINode(F.getReturnType(), "UnifiedRetVal");
NewRetBlock->getInstList().push_back(PN);
// Add an incoming element to the PHI node for every return instruction that
//
for (vector<BasicBlock*>::iterator I = ReturningBlocks.begin(),
E = ReturningBlocks.end(); I != E; ++I) {
- delete (*I)->getInstList().pop_back(); // Remove the return insn
+ (*I)->getInstList().pop_back(); // Remove the return insn
(*I)->getInstList().push_back(new BranchInst(NewRetBlock));
}
ExitNode = NewRetBlock;