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Invalidate debug/eh/gc labels when unreachable MBB is deleted.

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Based on patch by Martin Nowack!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@58536 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Anton Korobeynikov 2008-10-31 20:08:30 +00:00
parent 2583b2a713
commit ed532cac7c
1 changed files with 27 additions and 13 deletions
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40
lib/CodeGen/UnreachableBlockElim.cpp
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@ -27,6 +27,7 @@
#include "llvm/Pass.h"
#include "llvm/Type.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/CodeGen/MachineModuleInfo.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/Support/CFG.h"
#include "llvm/Support/Compiler.h"
@ -84,10 +85,10 @@ bool UnreachableBlockElim::runOnFunction(Function &F) {
namespace {
class VISIBILITY_HIDDEN UnreachableMachineBlockElim :
class VISIBILITY_HIDDEN UnreachableMachineBlockElim :
public MachineFunctionPass {
virtual bool runOnMachineFunction(MachineFunction &F);
MachineModuleInfo *MMI;
public:
static char ID; // Pass identification, replacement for typeid
UnreachableMachineBlockElim() : MachineFunctionPass(&ID) {}
@ -104,6 +105,8 @@ const PassInfo *const llvm::UnreachableMachineBlockElimID = &Y;
bool UnreachableMachineBlockElim::runOnMachineFunction(MachineFunction &F) {
SmallPtrSet<MachineBasicBlock*, 8> Reachable;
MMI = getAnalysisToUpdate<MachineModuleInfo>();
// Mark all reachable blocks.
for (df_ext_iterator<MachineFunction*, SmallPtrSet<MachineBasicBlock*, 8> >
I = df_ext_begin(&F, Reachable), E = df_ext_end(&F, Reachable);
@ -115,14 +118,14 @@ bool UnreachableMachineBlockElim::runOnMachineFunction(MachineFunction &F) {
std::vector<MachineBasicBlock*> DeadBlocks;
for (MachineFunction::iterator I = F.begin(), E = F.end(); I != E; ++I) {
MachineBasicBlock *BB = I;
// Test for deadness.
if (!Reachable.count(BB)) {
DeadBlocks.push_back(BB);
while (BB->succ_begin() != BB->succ_end()) {
MachineBasicBlock* succ = *BB->succ_begin();
MachineBasicBlock::iterator start = succ->begin();
while (start != succ->end() &&
start->getOpcode() == TargetInstrInfo::PHI) {
@ -132,24 +135,36 @@ bool UnreachableMachineBlockElim::runOnMachineFunction(MachineFunction &F) {
start->RemoveOperand(i);
start->RemoveOperand(i-1);
}
start++;
}
BB->removeSuccessor(BB->succ_begin());
}
}
}
// Actually remove the blocks now.
for (unsigned i = 0, e = DeadBlocks.size(); i != e; ++i)
DeadBlocks[i]->eraseFromParent();
for (unsigned i = 0, e = DeadBlocks.size(); i != e; ++i) {
MachineBasicBlock *MBB = DeadBlocks[i];
// If there are any labels in the basic block, unregister them from
// MachineModuleInfo.
if (MMI && !MBB->empty()) {
for (MachineBasicBlock::iterator I = MBB->begin(),
E = MBB->end(); I != E; ++I) {
if (I->isLabel())
// The label ID # is always operand #0, an immediate.
MMI->InvalidateLabel(I->getOperand(0).getImm());
}
}
MBB->eraseFromParent();
}
// Cleanup PHI nodes.
for (MachineFunction::iterator I = F.begin(), E = F.end(); I != E; ++I) {
MachineBasicBlock *BB = I;
// Prune unneeded PHI entries.
SmallPtrSet<MachineBasicBlock*, 8> preds(BB->pred_begin(),
SmallPtrSet<MachineBasicBlock*, 8> preds(BB->pred_begin(),
BB->pred_end());
MachineBasicBlock::iterator phi = BB->begin();
while (phi != BB->end() &&
@ -159,7 +174,7 @@ bool UnreachableMachineBlockElim::runOnMachineFunction(MachineFunction &F) {
phi->RemoveOperand(i);
phi->RemoveOperand(i-1);
}
if (phi->getNumOperands() == 3) {
unsigned Input = phi->getOperand(1).getReg();
unsigned Output = phi->getOperand(0).getReg();
@ -173,7 +188,7 @@ bool UnreachableMachineBlockElim::runOnMachineFunction(MachineFunction &F) {
continue;
}
++phi;
}
}
@ -182,4 +197,3 @@ bool UnreachableMachineBlockElim::runOnMachineFunction(MachineFunction &F) {
return DeadBlocks.size();
}