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Mark the invoke call instruction as implicitly defining the callee-saved registers. 

The callee-saved registers cannot be live across an invoke call because the
control flow may continue along the exceptional edge. When this happens, all of
the callee-saved registers are no longer valid.

llvm-svn: 142018
This commit is contained in:
Bill Wendling 2011-10-14 23:34:37 +00:00
parent f82017f3fe
commit 6f3f9a391e
1 changed files with 31 additions and 2 deletions
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33
llvm/lib/Target/ARM/ARMISelLowering.cpp
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@ -5883,11 +5883,15 @@ EmitSjLjDispatchBlock(MachineInstr *MI, MachineBasicBlock *MBB) const {
PrevMBB = CurMBB;
}
// Remove the landing pad successor from the invoke block and replace it with
// the new dispatch block.
const ARMBaseInstrInfo *AII = static_cast<const ARMBaseInstrInfo*>(TII);
const ARMBaseRegisterInfo &RI = AII->getRegisterInfo();
const unsigned *SavedRegs = RI.getCalleeSavedRegs(MF);
for (SmallPtrSet<MachineBasicBlock*, 64>::iterator
I = InvokeBBs.begin(), E = InvokeBBs.end(); I != E; ++I) {
MachineBasicBlock *BB = *I;
// Remove the landing pad successor from the invoke block and replace it
// with the new dispatch block.
for (MachineBasicBlock::succ_iterator
SI = BB->succ_begin(), SE = BB->succ_end(); SI != SE; ++SI) {
MachineBasicBlock *SMBB = *SI;
@ -5898,6 +5902,31 @@ EmitSjLjDispatchBlock(MachineInstr *MI, MachineBasicBlock *MBB) const {
}
BB->addSuccessor(DispatchBB);
// Find the invoke call and mark all of the callee-saved registers as
// 'implicit defined' so that they're spilled. This prevents code from
// moving instructions to before the EH block, where they will never be
// executed.
for (MachineBasicBlock::reverse_iterator
II = BB->rbegin(), IE = BB->rend(); II != IE; ++II) {
if (!II->getDesc().isCall()) continue;
DenseMap<unsigned, bool> DefRegs;
for (MachineInstr::mop_iterator
OI = II->operands_begin(), OE = II->operands_end();
OI != OE; ++OI) {
if (!OI->isReg()) continue;
DefRegs[OI->getReg()] = true;
}
MachineInstrBuilder MIB(&*II);
for (unsigned i = 0; SavedRegs[i] != 0; ++i)
if (!DefRegs[SavedRegs[i]])
MIB.addReg(SavedRegs[i], RegState::Implicit | RegState::Define);
break;
}
}
// The instruction is gone now.