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Reland [CFIFixup] Factor CFI remember/restore insertion into a helper (NFC) (#113328)

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The previous submission looked like it triggered build failure
https://lab.llvm.org/buildbot/#/builders/17/builds/3116, but this
appears to be a spurious failure due to a flaky test.
This commit is contained in:
Daniel Hoekwater
2024-10-22 10:57:47 -04:00
committed by GitHub
parent 1004865f1c
commit ac1a01f533
1 changed files with 30 additions and 16 deletions
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46
llvm/lib/CodeGen/CFIFixup.cpp
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@@ -116,6 +116,32 @@ findPrologueEnd(MachineFunction &MF, MachineBasicBlock::iterator &PrologueEnd) {
return nullptr;
}
// Inserts a `.cfi_remember_state` instruction before PrologueEnd and a
// `.cfi_restore_state` instruction before DstInsertPt. Returns an iterator
// to the first instruction after the inserted `.cfi_restore_state` instruction.
static MachineBasicBlock::iterator
insertRememberRestorePair(MachineBasicBlock::iterator RememberInsertPt,
MachineBasicBlock::iterator RestoreInsertPt) {
MachineBasicBlock *RememberMBB = RememberInsertPt->getParent();
MachineBasicBlock *RestoreMBB = RestoreInsertPt->getParent();
MachineFunction &MF = *RememberMBB->getParent();
const TargetInstrInfo &TII = *MF.getSubtarget().getInstrInfo();
// Insert the `.cfi_remember_state` instruction.
unsigned CFIIndex =
MF.addFrameInst(MCCFIInstruction::createRememberState(nullptr));
BuildMI(*RememberMBB, RememberInsertPt, DebugLoc(),
TII.get(TargetOpcode::CFI_INSTRUCTION))
.addCFIIndex(CFIIndex);
// Insert the `.cfi_restore_state` instruction.
CFIIndex = MF.addFrameInst(MCCFIInstruction::createRestoreState(nullptr));
BuildMI(*RestoreMBB, RestoreInsertPt, DebugLoc(),
TII.get(TargetOpcode::CFI_INSTRUCTION))
.addCFIIndex(CFIIndex);
return RestoreInsertPt;
}
bool CFIFixup::runOnMachineFunction(MachineFunction &MF) {
const TargetFrameLowering &TFL = *MF.getSubtarget().getFrameLowering();
if (!TFL.enableCFIFixup(MF))
@@ -174,12 +200,10 @@ bool CFIFixup::runOnMachineFunction(MachineFunction &MF) {
// Every block inherits the frame state (as recorded in the unwind tables)
// of the previous block. If the intended frame state is different, insert
// compensating CFI instructions.
const TargetInstrInfo &TII = *MF.getSubtarget().getInstrInfo();
bool Change = false;
// `InsertPt` always points to the point in a preceding block where we have to
// insert a `.cfi_remember_state`, in the case that the current block needs a
// `.cfi_restore_state`.
MachineBasicBlock *InsertMBB = PrologueBlock;
MachineBasicBlock::iterator InsertPt = PrologueEnd;
assert(InsertPt != PrologueBlock->begin() &&
@@ -210,20 +234,10 @@ bool CFIFixup::runOnMachineFunction(MachineFunction &MF) {
if (!Info.StrongNoFrameOnEntry && Info.HasFrameOnEntry && !HasFrame) {
// Reset to the "after prologue" state.
// Insert a `.cfi_remember_state` into the last block known to have a
// stack frame.
unsigned CFIIndex =
MF.addFrameInst(MCCFIInstruction::createRememberState(nullptr));
BuildMI(*InsertMBB, InsertPt, DebugLoc(),
TII.get(TargetOpcode::CFI_INSTRUCTION))
.addCFIIndex(CFIIndex);
// Insert a `.cfi_restore_state` at the beginning of the current block.
CFIIndex = MF.addFrameInst(MCCFIInstruction::createRestoreState(nullptr));
InsertPt = BuildMI(*CurrBB, CurrBB->begin(), DebugLoc(),
TII.get(TargetOpcode::CFI_INSTRUCTION))
.addCFIIndex(CFIIndex);
++InsertPt;
InsertMBB = &*CurrBB;
// There's an earlier block known to have a stack frame. Insert a
// `.cfi_remember_state` instruction into that block and a
// `.cfi_restore_state` instruction at the beginning of the current block.
InsertPt = insertRememberRestorePair(InsertPt, CurrBB->begin());
Change = true;
} else if ((Info.StrongNoFrameOnEntry || !Info.HasFrameOnEntry) &&
HasFrame) {