[CodeGen] Force emission of personality directive if explicitly specified
Summary:
Before this change, personality directives were not emitted
if there was no invoke left in the function (of course until
recently this also meant that we couldn't know what
the personality actually was). This patch forces personality directives
to still be emitted, unless it is known to be a noop in the absence of
invokes, or the user explicitly specified `nounwind` (and not
`uwtable`) on the function.
Reviewers: majnemer, rnk
Subscribers: rnk, llvm-commits
Differential Revision: http://reviews.llvm.org/D10884
llvm-svn: 242185
diff --git a/llvm/lib/CodeGen/AsmPrinter/ARMException.cpp b/llvm/lib/CodeGen/AsmPrinter/ARMException.cpp
index 4cb460a..0bad795 100644
--- a/llvm/lib/CodeGen/AsmPrinter/ARMException.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/ARMException.cpp
@@ -69,24 +69,32 @@
///
void ARMException::endFunction(const MachineFunction *MF) {
ARMTargetStreamer &ATS = getTargetStreamer();
+ const Function *F = MF->getFunction();
+ const Function *Per = nullptr;
+ if (F->hasPersonalityFn())
+ Per = dyn_cast<Function>(F->getPersonalityFn()->stripPointerCasts());
+ assert(!MMI->getPersonality() || Per == MMI->getPersonality());
+ bool forceEmitPersonality =
+ F->hasPersonalityFn() && !isNoOpWithoutInvoke(classifyEHPersonality(Per)) &&
+ F->needsUnwindTableEntry();
+ bool shouldEmitPersonality = forceEmitPersonality ||
+ !MMI->getLandingPads().empty();
if (!Asm->MF->getFunction()->needsUnwindTableEntry() &&
- MMI->getLandingPads().empty())
+ !shouldEmitPersonality)
ATS.emitCantUnwind();
- else {
- if (!MMI->getLandingPads().empty()) {
- // Emit references to personality.
- if (const Function *Personality = MMI->getPersonality()) {
- MCSymbol *PerSym = Asm->getSymbol(Personality);
- Asm->OutStreamer->EmitSymbolAttribute(PerSym, MCSA_Global);
- ATS.emitPersonality(PerSym);
- }
-
- // Emit .handlerdata directive.
- ATS.emitHandlerData();
-
- // Emit actual exception table
- emitExceptionTable();
+ else if (shouldEmitPersonality) {
+ // Emit references to personality.
+ if (Per) {
+ MCSymbol *PerSym = Asm->getSymbol(Per);
+ Asm->OutStreamer->EmitSymbolAttribute(PerSym, MCSA_Global);
+ ATS.emitPersonality(PerSym);
}
+
+ // Emit .handlerdata directive.
+ ATS.emitHandlerData();
+
+ // Emit actual exception table
+ emitExceptionTable();
}
if (Asm->MAI->getExceptionHandlingType() == ExceptionHandling::ARM)
diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfCFIException.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfCFIException.cpp
index 0bc873e..2c212c7 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfCFIException.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfCFIException.cpp
@@ -89,6 +89,7 @@
void DwarfCFIException::beginFunction(const MachineFunction *MF) {
shouldEmitMoves = shouldEmitPersonality = shouldEmitLSDA = false;
+ const Function *F = MF->getFunction();
// If any landing pads survive, we need an EH table.
bool hasLandingPads = !MMI->getLandingPads().empty();
@@ -104,10 +105,24 @@
const TargetLoweringObjectFile &TLOF = Asm->getObjFileLowering();
unsigned PerEncoding = TLOF.getPersonalityEncoding();
- const Function *Per = MMI->getPersonality();
+ const Function *Per = nullptr;
+ if (F->hasPersonalityFn())
+ Per = dyn_cast<Function>(F->getPersonalityFn()->stripPointerCasts());
+ assert(!MMI->getPersonality() || Per == MMI->getPersonality());
- shouldEmitPersonality = hasLandingPads &&
- PerEncoding != dwarf::DW_EH_PE_omit && Per;
+ // Emit a personality function even when there are no landing pads
+ bool forceEmitPersonality =
+ // ...if a personality function is explicitly specified
+ F->hasPersonalityFn() &&
+ // ... and it's not known to be a noop in the absence of invokes
+ !isNoOpWithoutInvoke(classifyEHPersonality(Per)) &&
+ // ... and we're not explicitly asked not to emit it
+ F->needsUnwindTableEntry();
+
+ shouldEmitPersonality =
+ (forceEmitPersonality ||
+ (hasLandingPads && PerEncoding != dwarf::DW_EH_PE_omit)) &&
+ Per;
unsigned LSDAEncoding = TLOF.getLSDAEncoding();
shouldEmitLSDA = shouldEmitPersonality &&
@@ -123,6 +138,11 @@
if (!shouldEmitPersonality)
return;
+ // If we are forced to emit this personality, make sure to record
+ // it because it might not appear in any landingpad
+ if (forceEmitPersonality)
+ MMI->addPersonality(Per);
+
const MCSymbol *Sym =
TLOF.getCFIPersonalitySymbol(Per, *Asm->Mang, Asm->TM, MMI);
Asm->OutStreamer->EmitCFIPersonality(Sym, PerEncoding);
diff --git a/llvm/lib/CodeGen/AsmPrinter/EHStreamer.cpp b/llvm/lib/CodeGen/AsmPrinter/EHStreamer.cpp
index 1be3fd7..49ef8d3 100644
--- a/llvm/lib/CodeGen/AsmPrinter/EHStreamer.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/EHStreamer.cpp
@@ -309,7 +309,7 @@
// If some instruction between the previous try-range and the end of the
// function may throw, create a call-site entry with no landing pad for the
// region following the try-range.
- if (SawPotentiallyThrowing && !IsSJLJ) {
+ if (SawPotentiallyThrowing && !IsSJLJ && LastLabel != nullptr) {
CallSiteEntry Site = { LastLabel, nullptr, nullptr, 0 };
CallSites.push_back(Site);
}
diff --git a/llvm/lib/CodeGen/AsmPrinter/WinException.cpp b/llvm/lib/CodeGen/AsmPrinter/WinException.cpp
index 7ef2832..71c7781 100644
--- a/llvm/lib/CodeGen/AsmPrinter/WinException.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/WinException.cpp
@@ -74,8 +74,12 @@
if (F->hasPersonalityFn())
Per = dyn_cast<Function>(F->getPersonalityFn()->stripPointerCasts());
- shouldEmitPersonality = hasLandingPads &&
- PerEncoding != dwarf::DW_EH_PE_omit && Per;
+ bool forceEmitPersonality =
+ F->hasPersonalityFn() && !isNoOpWithoutInvoke(classifyEHPersonality(Per)) &&
+ F->needsUnwindTableEntry();
+
+ shouldEmitPersonality = forceEmitPersonality || (hasLandingPads &&
+ PerEncoding != dwarf::DW_EH_PE_omit && Per);
unsigned LSDAEncoding = TLOF.getLSDAEncoding();
shouldEmitLSDA = shouldEmitPersonality &&
diff --git a/llvm/lib/CodeGen/MachineModuleInfo.cpp b/llvm/lib/CodeGen/MachineModuleInfo.cpp
index 42d0603..6a20624 100644
--- a/llvm/lib/CodeGen/MachineModuleInfo.cpp
+++ b/llvm/lib/CodeGen/MachineModuleInfo.cpp
@@ -320,7 +320,10 @@
const Function *Personality) {
LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
LP.Personality = Personality;
+ addPersonality(Personality);
+}
+void MachineModuleInfo::addPersonality(const Function *Personality) {
for (unsigned i = 0; i < Personalities.size(); ++i)
if (Personalities[i] == Personality)
return;