replica
/
hanchenye-llvm-project
2
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

Handle 'ret' with multiple values. 

llvm-svn: 47965
This commit is contained in:
Devang Patel 2008-03-05 21:50:24 +00:00
parent 7034236366
commit 3b1c95f885
1 changed files with 25 additions and 13 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

34
llvm/lib/Transforms/Utils/UnifyFunctionExitNodes.cpp
View File

@ -20,6 +20,7 @@
#include "llvm/Function.h" #include "llvm/Function.h"
#include "llvm/Instructions.h" #include "llvm/Instructions.h"
#include "llvm/Type.h" #include "llvm/Type.h"
#include "llvm/ADT/SmallVector.h"
using namespace llvm; using namespace llvm;
char UnifyFunctionExitNodes::ID = 0; char UnifyFunctionExitNodes::ID = 0;
@ -50,11 +51,6 @@ bool UnifyFunctionExitNodes::runOnFunction(Function &F) {
// Loop over all of the blocks in a function, tracking all of the blocks that // Loop over all of the blocks in a function, tracking all of the blocks that
// return. // return.
// //
// PHINode can not handle aggregates returned by multiple value ret
// instructions. TODO: Handle each return value independently.
if (isa<StructType>(F.getReturnType()))
return false;
std::vector<BasicBlock*> ReturningBlocks; std::vector<BasicBlock*> ReturningBlocks;
std::vector<BasicBlock*> UnwindingBlocks; std::vector<BasicBlock*> UnwindingBlocks;
std::vector<BasicBlock*> UnreachableBlocks; std::vector<BasicBlock*> UnreachableBlocks;
@ -110,18 +106,30 @@ bool UnifyFunctionExitNodes::runOnFunction(Function &F) {
} }
// Otherwise, we need to insert a new basic block into the function, add a PHI // 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. // instructions into unconditional branches.
// //
BasicBlock *NewRetBlock = new BasicBlock("UnifiedReturnBlock", &F); BasicBlock *NewRetBlock = new BasicBlock("UnifiedReturnBlock", &F);
PHINode *PN = 0; SmallVector<Value *, 4> Phis;
if (F.getReturnType() != Type::VoidTy) { unsigned NumRetVals = ReturningBlocks[0]->getTerminator()->getNumOperands();
// If the function doesn't return void... add a PHI node to the block... if (NumRetVals == 0)
PN = new PHINode(F.getReturnType(), "UnifiedRetVal"); new ReturnInst(NULL, NewRetBlock);
else if (const StructType *STy = dyn_cast<StructType>(F.getReturnType())) {
for (unsigned i = 0; i < NumRetVals; ++i) {
PHINode *PN = new PHINode(STy->getElementType(i), "UnifiedRetVal");
NewRetBlock->getInstList().push_back(PN); NewRetBlock->getInstList().push_back(PN);
Phis.push_back(PN);
} }
new ReturnInst(&Phis[0], NumRetVals);
}
else {
// If the function doesn't return void... add a PHI node to the block...
PHINode *PN = new PHINode(F.getReturnType(), "UnifiedRetVal");
NewRetBlock->getInstList().push_back(PN);
Phis.push_back(PN);
new ReturnInst(PN, NewRetBlock); new ReturnInst(PN, NewRetBlock);
}
// Loop over all of the blocks, replacing the return instruction with an // Loop over all of the blocks, replacing the return instruction with an
// unconditional branch. // unconditional branch.
@ -132,7 +140,11 @@ bool UnifyFunctionExitNodes::runOnFunction(Function &F) {
// Add an incoming element to the PHI node for every return instruction that // Add an incoming element to the PHI node for every return instruction that
// is merging into this new block... // is merging into this new block...
if (PN) PN->addIncoming(BB->getTerminator()->getOperand(0), BB); if (!Phis.empty()) {
for (unsigned i = 0; i < NumRetVals; ++i)
cast<PHINode>(Phis[i])->addIncoming(BB->getTerminator()->getOperand(i),
BB);
}
BB->getInstList().pop_back(); // Remove the return insn BB->getInstList().pop_back(); // Remove the return insn
new BranchInst(NewRetBlock, BB); new BranchInst(NewRetBlock, BB);