[WinEH] Fix ip2state table emission with funclets
Previously we were hijacking the old LandingPadInfo data structures to
communicate our state numbers. Now we don't need that anymore.
llvm-svn: 248763
diff --git a/llvm/lib/CodeGen/AsmPrinter/WinException.cpp b/llvm/lib/CodeGen/AsmPrinter/WinException.cpp
index 95947cb..f662a1b 100644
--- a/llvm/lib/CodeGen/AsmPrinter/WinException.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/WinException.cpp
@@ -176,6 +176,12 @@
return create32bitRef(MMI->getAddrLabelSymbol(cast<BasicBlock>(V)));
}
+const MCExpr *WinException::getLabelPlusOne(MCSymbol *Label) {
+ return MCBinaryExpr::createAdd(create32bitRef(Label),
+ MCConstantExpr::create(1, Asm->OutContext),
+ Asm->OutContext);
+}
+
/// Emit the language-specific data that __C_specific_handler expects. This
/// handler lives in the x64 Microsoft C runtime and allows catching or cleaning
/// up after faults with __try, __except, and __finally. The typeinfo values
@@ -263,9 +269,7 @@
if (CSE.EndLabel) {
// The interval is half-open, so we have to add one to include the return
// address of the last invoke in the range.
- End = MCBinaryExpr::createAdd(create32bitRef(CSE.EndLabel),
- MCConstantExpr::create(1, Asm->OutContext),
- Asm->OutContext);
+ End = getLabelPlusOne(CSE.EndLabel);
} else {
End = create32bitRef(EHFuncEndSym);
}
@@ -312,13 +316,15 @@
StringRef FuncLinkageName = GlobalValue::getRealLinkageName(F->getName());
+ SmallVector<std::pair<const MCExpr *, int>, 4> IPToStateTable;
MCSymbol *FuncInfoXData = nullptr;
if (shouldEmitPersonality) {
+ // If we're 64-bit, emit a pointer to the C++ EH data, and build a map from
+ // IPs to state numbers.
FuncInfoXData =
Asm->OutContext.getOrCreateSymbol(Twine("$cppxdata$", FuncLinkageName));
OS.EmitValue(create32bitRef(FuncInfoXData), 4);
-
- extendIP2StateTable(MF, FuncInfo);
+ computeIP2StateTable(MF, FuncInfo, IPToStateTable);
} else {
FuncInfoXData = Asm->OutContext.getOrCreateLSDASymbol(FuncLinkageName);
emitEHRegistrationOffsetLabel(FuncInfo, FuncLinkageName);
@@ -333,7 +339,7 @@
if (!FuncInfo.TryBlockMap.empty())
TryBlockMapXData =
Asm->OutContext.getOrCreateSymbol(Twine("$tryMap$", FuncLinkageName));
- if (!FuncInfo.IPToStateList.empty())
+ if (!IPToStateTable.empty())
IPToStateXData =
Asm->OutContext.getOrCreateSymbol(Twine("$ip2state$", FuncLinkageName));
@@ -359,7 +365,7 @@
OS.EmitValue(create32bitRef(UnwindMapXData), 4); // UnwindMap
OS.EmitIntValue(FuncInfo.TryBlockMap.size(), 4); // NumTryBlocks
OS.EmitValue(create32bitRef(TryBlockMapXData), 4); // TryBlockMap
- OS.EmitIntValue(FuncInfo.IPToStateList.size(), 4); // IPMapEntries
+ OS.EmitIntValue(IPToStateTable.size(), 4); // IPMapEntries
OS.EmitValue(create32bitRef(IPToStateXData), 4); // IPToStateMap
if (Asm->MAI->usesWindowsCFI())
OS.EmitIntValue(FuncInfo.UnwindHelpFrameOffset, 4); // UnwindHelp
@@ -477,80 +483,87 @@
// };
if (IPToStateXData) {
OS.EmitLabel(IPToStateXData);
- for (auto &IPStatePair : FuncInfo.IPToStateList) {
- OS.EmitValue(create32bitRef(IPStatePair.first), 4); // IP
- OS.EmitIntValue(IPStatePair.second, 4); // State
+ for (auto &IPStatePair : IPToStateTable) {
+ OS.EmitValue(IPStatePair.first, 4); // IP
+ OS.EmitIntValue(IPStatePair.second, 4); // State
}
}
}
-void WinException::extendIP2StateTable(const MachineFunction *MF,
- WinEHFuncInfo &FuncInfo) {
- // The Itanium LSDA table sorts similar landing pads together to simplify the
- // actions table, but we don't need that.
- SmallVector<const LandingPadInfo *, 64> LandingPads;
- const std::vector<LandingPadInfo> &PadInfos = MMI->getLandingPads();
- LandingPads.reserve(PadInfos.size());
- for (const auto &LP : PadInfos)
- LandingPads.push_back(&LP);
-
- RangeMapType PadMap;
- computePadMap(LandingPads, PadMap);
-
- // The end label of the previous invoke or nounwind try-range.
- MCSymbol *LastLabel = Asm->getFunctionBegin();
-
+void WinException::computeIP2StateTable(
+ const MachineFunction *MF, WinEHFuncInfo &FuncInfo,
+ SmallVectorImpl<std::pair<const MCExpr *, int>> &IPToStateTable) {
// Whether there is a potentially throwing instruction (currently this means
// an ordinary call) between the end of the previous try-range and now.
- bool SawPotentiallyThrowing = false;
+ bool SawPotentiallyThrowing = true;
- int LastEHState = -2;
+ // Remember what state we were in the last time we found a begin try label.
+ // This allows us to coalesce many nearby invokes with the same state into one
+ // entry.
+ int LastEHState = -1;
+ MCSymbol *LastEndLabel = Asm->getFunctionBegin();
+ assert(LastEndLabel && "need local function start label");
- // The parent function and the catch handlers contribute to the 'ip2state'
- // table.
+ // Indicate that all calls from the prologue to the first invoke unwind to
+ // caller. We handle this as a special case since other ranges starting at end
+ // labels need to use LtmpN+1.
+ IPToStateTable.push_back(std::make_pair(create32bitRef(LastEndLabel), -1));
- // Include ip2state entries for the beginning of the main function and
- // for catch handler functions.
- FuncInfo.IPToStateList.push_back(std::make_pair(LastLabel, -1));
- LastEHState = -1;
for (const auto &MBB : *MF) {
+ // FIXME: Do we need to emit entries for funclet base states?
+
for (const auto &MI : MBB) {
+ // Find all the EH_LABEL instructions, tracking if we've crossed a
+ // potentially throwing call since the last label.
if (!MI.isEHLabel()) {
if (MI.isCall())
SawPotentiallyThrowing |= !callToNoUnwindFunction(&MI);
continue;
}
- // End of the previous try-range?
- MCSymbol *BeginLabel = MI.getOperand(0).getMCSymbol();
- if (BeginLabel == LastLabel)
+ // If this was an end label, return SawPotentiallyThrowing to the start
+ // state and keep going. Otherwise, we will consider the call between the
+ // begin/end labels to be a potentially throwing call and generate extra
+ // table entries.
+ MCSymbol *Label = MI.getOperand(0).getMCSymbol();
+ if (Label == LastEndLabel)
SawPotentiallyThrowing = false;
- // Beginning of a new try-range?
- RangeMapType::const_iterator L = PadMap.find(BeginLabel);
- if (L == PadMap.end())
- // Nope, it was just some random label.
+ // Check if this was a begin label. Otherwise, it must be an end label or
+ // some random label, and we should continue.
+ auto StateAndEnd = FuncInfo.InvokeToStateMap.find(Label);
+ if (StateAndEnd == FuncInfo.InvokeToStateMap.end())
continue;
- const PadRange &P = L->second;
- const LandingPadInfo *LandingPad = LandingPads[P.PadIndex];
- assert(BeginLabel == LandingPad->BeginLabels[P.RangeIndex] &&
- "Inconsistent landing pad map!");
+ // Extract the state and end label.
+ int State;
+ MCSymbol *EndLabel;
+ std::tie(State, EndLabel) = StateAndEnd->second;
- // FIXME: Should this be using FuncInfo.HandlerBaseState?
+ // If there was a potentially throwing call between this begin label and
+ // the last end label, we need an extra base state entry to indicate that
+ // those calls unwind directly to the caller.
if (SawPotentiallyThrowing && LastEHState != -1) {
- FuncInfo.IPToStateList.push_back(std::make_pair(LastLabel, -1));
+ IPToStateTable.push_back(
+ std::make_pair(getLabelPlusOne(LastEndLabel), -1));
SawPotentiallyThrowing = false;
LastEHState = -1;
}
- if (LandingPad->WinEHState != LastEHState)
- FuncInfo.IPToStateList.push_back(
- std::make_pair(BeginLabel, LandingPad->WinEHState));
- LastEHState = LandingPad->WinEHState;
- LastLabel = LandingPad->EndLabels[P.RangeIndex];
+ // Emit an entry indicating that PCs after 'Label' have this EH state.
+ if (State != LastEHState)
+ IPToStateTable.push_back(std::make_pair(create32bitRef(Label), State));
+ LastEHState = State;
+ LastEndLabel = EndLabel;
}
}
+
+ if (LastEndLabel != Asm->getFunctionBegin()) {
+ // Indicate that all calls from the last invoke until the epilogue unwind to
+ // caller. This also ensures that we have at least one ip2state entry, if
+ // somehow all invokes were deleted during CodeGen.
+ IPToStateTable.push_back(std::make_pair(getLabelPlusOne(LastEndLabel), -1));
+ }
}
void WinException::emitEHRegistrationOffsetLabel(const WinEHFuncInfo &FuncInfo,