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Use iteration instead of recursion in CFIInserter

Browse Source 
Summary: This recursive step can overflow the stack.

Reviewers: djokov, petarj

Subscribers: mcrosier, jlebar, bixia, llvm-commits

Differential Revision: https://reviews.llvm.org/D46671

llvm-svn: 332101
This commit is contained in:
Sanjoy Das 2018-05-11 15:54:46 +00:00
parent 3999513966
commit 42e300425d
2 changed files with 43 additions and 15 deletions
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41
lib/CodeGen/CFIInstrInserter.cpp
View File

@ -151,7 +151,6 @@ void CFIInstrInserter::calculateCFAInfo(MachineFunction &MF) {
// information.
for (MachineBasicBlock &MBB : MF) {
if (MBBVector[MBB.getNumber()].Processed) continue;
calculateOutgoingCFAInfo(MBBVector[MBB.getNumber()]);
updateSuccCFAInfo(MBBVector[MBB.getNumber()]);
}
}
@ -222,14 +221,25 @@ void CFIInstrInserter::calculateOutgoingCFAInfo(MBBCFAInfo &MBBInfo) {
}
void CFIInstrInserter::updateSuccCFAInfo(MBBCFAInfo &MBBInfo) {
for (MachineBasicBlock *Succ : MBBInfo.MBB->successors()) {
MBBCFAInfo &SuccInfo = MBBVector[Succ->getNumber()];
if (SuccInfo.Processed) continue;
SuccInfo.IncomingCFAOffset = MBBInfo.OutgoingCFAOffset;
SuccInfo.IncomingCFARegister = MBBInfo.OutgoingCFARegister;
calculateOutgoingCFAInfo(SuccInfo);
updateSuccCFAInfo(SuccInfo);
}
SmallVector<MachineBasicBlock *, 4> Stack;
Stack.push_back(MBBInfo.MBB);
do {
MachineBasicBlock *Current = Stack.pop_back_val();
MBBCFAInfo &CurrentInfo = MBBVector[Current->getNumber()];
if (CurrentInfo.Processed)
continue;
calculateOutgoingCFAInfo(CurrentInfo);
for (auto *Succ : CurrentInfo.MBB->successors()) {
MBBCFAInfo &SuccInfo = MBBVector[Succ->getNumber()];
if (!SuccInfo.Processed) {
SuccInfo.IncomingCFAOffset = CurrentInfo.OutgoingCFAOffset;
SuccInfo.IncomingCFARegister = CurrentInfo.OutgoingCFARegister;
Stack.push_back(Succ);
}
}
} while (!Stack.empty());
}
bool CFIInstrInserter::insertCFIInstrs(MachineFunction &MF) {
@ -282,17 +292,18 @@ bool CFIInstrInserter::insertCFIInstrs(MachineFunction &MF) {
return InsertedCFIInstr;
}
void CFIInstrInserter::report(const MBBCFAInfo &Pred,
const MBBCFAInfo &Succ) {
void CFIInstrInserter::report(const MBBCFAInfo &Pred, const MBBCFAInfo &Succ) {
errs() << "*** Inconsistent CFA register and/or offset between pred and succ "
"***\n";
errs() << "Pred: " << Pred.MBB->getName()
errs() << "Pred: " << Pred.MBB->getName() << " #" << Pred.MBB->getNumber()
<< " in " << Pred.MBB->getParent()->getName()
<< " outgoing CFA Reg:" << Pred.OutgoingCFARegister << "\n";
errs() << "Pred: " << Pred.MBB->getName()
errs() << "Pred: " << Pred.MBB->getName() << " #" << Pred.MBB->getNumber()
<< " in " << Pred.MBB->getParent()->getName()
<< " outgoing CFA Offset:" << Pred.OutgoingCFAOffset << "\n";
errs() << "Succ: " << Succ.MBB->getName()
errs() << "Succ: " << Succ.MBB->getName() << " #" << Succ.MBB->getNumber()
<< " incoming CFA Reg:" << Succ.IncomingCFARegister << "\n";
errs() << "Succ: " << Succ.MBB->getName()
errs() << "Succ: " << Succ.MBB->getName() << " #" << Succ.MBB->getNumber()
<< " incoming CFA Offset:" << Succ.IncomingCFAOffset << "\n";
}

17
test/CodeGen/X86/cfi-inserter-cfg-with-merge.mir Normal file
View File

@ -0,0 +1,17 @@
# RUN: llc -o - %s -mtriple=x86_64-- -verify-cfiinstrs -run-pass=cfi-instr-inserter
--- |
define void @foo() { ret void }
...
---
name: foo
body: |
bb.0:
JE_1 %bb.3, implicit $eflags
bb.1:
CFI_INSTRUCTION def_cfa_offset 24
bb.2:
CFI_INSTRUCTION def_cfa_offset 8
bb.3:
RET 0
...