diff --git a/lib/CodeGen/DwarfWriter.cpp b/lib/CodeGen/DwarfWriter.cpp index d1f195d5567..1445a039227 100644 --- a/lib/CodeGen/DwarfWriter.cpp +++ b/lib/CodeGen/DwarfWriter.cpp @@ -3013,8 +3013,10 @@ private: /// CallSiteEntry - Structure describing an entry in the call-site table. struct CallSiteEntry { + // The 'try-range' is BeginLabel .. EndLabel. unsigned BeginLabel; // zero indicates the start of the function. unsigned EndLabel; // zero indicates the end of the function. + // The landing pad starts at PadLabel. unsigned PadLabel; // zero indicates that there is no landing pad. unsigned Action; }; @@ -3113,13 +3115,21 @@ private: SizeActions += SizeSiteActions; } - // Compute the call-site table. Entries must be ordered by address. + // Compute the call-site table. The entry for an invoke has a try-range + // containing the call, a non-zero landing pad and an appropriate action. + // The entry for an ordinary call has a try-range containing the call and + // zero for the landing pad and the action. Calls marked 'nounwind' have + // no entry and must not be contained in the try-range of any entry - they + // form gaps in the table. Entries must be ordered by try-range address. SmallVector CallSites; RangeMapType PadMap; + // Invokes and nounwind calls have entries in PadMap (due to being bracketed + // by try-range labels when lowered). Ordinary calls do not, so appropriate + // try-ranges for them need be deduced. for (unsigned i = 0, N = LandingPads.size(); i != N; ++i) { const LandingPadInfo *LandingPad = LandingPads[i]; - for (unsigned j=0, E = LandingPad->BeginLabels.size(); j != E; ++j) { + for (unsigned j = 0, E = LandingPad->BeginLabels.size(); j != E; ++j) { unsigned BeginLabel = LandingPad->BeginLabels[j]; assert(!PadMap.count(BeginLabel) && "Duplicate landing pad labels!"); PadRange P = { i, j }; @@ -3127,27 +3137,39 @@ private: } } - bool MayThrow = false; + // The end label of the previous invoke or nounwind try-range. unsigned LastLabel = 0; + + // 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; + + // Whether the last callsite entry was for an invoke. + bool PreviousIsInvoke = false; + const TargetInstrInfo *TII = MF->getTarget().getInstrInfo(); + + // Visit all instructions in order of address. for (MachineFunction::const_iterator I = MF->begin(), E = MF->end(); I != E; ++I) { for (MachineBasicBlock::const_iterator MI = I->begin(), E = I->end(); MI != E; ++MI) { if (MI->getOpcode() != TargetInstrInfo::LABEL) { - MayThrow |= TII->isCall(MI->getOpcode()); + SawPotentiallyThrowing |= TII->isCall(MI->getOpcode()); continue; } unsigned BeginLabel = MI->getOperand(0).getImmedValue(); assert(BeginLabel && "Invalid label!"); + // End of the previous try-range? if (BeginLabel == LastLabel) - MayThrow = false; + SawPotentiallyThrowing = false; + // Beginning of a new try-range? RangeMapType::iterator L = PadMap.find(BeginLabel); - if (L == PadMap.end()) + // Nope, it was just some random label. continue; PadRange P = L->second; @@ -3159,36 +3181,43 @@ private: // If some instruction between the previous try-range and this one may // throw, create a call-site entry with no landing pad for the region // between the try-ranges. - if (MayThrow) { + if (SawPotentiallyThrowing) { CallSiteEntry Site = {LastLabel, BeginLabel, 0, 0}; CallSites.push_back(Site); + PreviousIsInvoke = false; } LastLabel = LandingPad->EndLabels[P.RangeIndex]; - CallSiteEntry Site = {BeginLabel, LastLabel, - LandingPad->LandingPadLabel, FirstActions[P.PadIndex]}; + assert(BeginLabel && LastLabel && "Invalid landing pad!"); - assert(Site.BeginLabel && Site.EndLabel && Site.PadLabel && - "Invalid landing pad!"); + if (LandingPad->LandingPadLabel) { + // This try-range is for an invoke. + CallSiteEntry Site = {BeginLabel, LastLabel, + LandingPad->LandingPadLabel, FirstActions[P.PadIndex]}; - // Try to merge with the previous call-site. - if (CallSites.size()) { - CallSiteEntry &Prev = CallSites[CallSites.size()-1]; - if (Site.PadLabel == Prev.PadLabel && Site.Action == Prev.Action) { - // Extend the range of the previous entry. - Prev.EndLabel = Site.EndLabel; - continue; + // Try to merge with the previous call-site. + if (PreviousIsInvoke) { + CallSiteEntry &Prev = CallSites[CallSites.size()-1]; + if (Site.PadLabel == Prev.PadLabel && Site.Action == Prev.Action) { + // Extend the range of the previous entry. + Prev.EndLabel = Site.EndLabel; + continue; + } } - } - // Otherwise, create a new call-site. - CallSites.push_back(Site); + // Otherwise, create a new call-site. + CallSites.push_back(Site); + PreviousIsInvoke = true; + } else { + // Create a gap. + PreviousIsInvoke = false; + } } } // 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 (MayThrow) { + if (SawPotentiallyThrowing) { CallSiteEntry Site = {LastLabel, 0, 0, 0}; CallSites.push_back(Site); } diff --git a/lib/CodeGen/MachineModuleInfo.cpp b/lib/CodeGen/MachineModuleInfo.cpp index 14253f41117..59c335e7fb0 100644 --- a/lib/CodeGen/MachineModuleInfo.cpp +++ b/lib/CodeGen/MachineModuleInfo.cpp @@ -1747,7 +1747,7 @@ void MachineModuleInfo::TidyLandingPads() { LandingPad.LandingPadLabel = MappedLabel(LandingPad.LandingPadLabel); // Special case: we *should* emit LPs with null LP MBB. This indicates - // "rethrow" case. + // "nounwind" case. if (!LandingPad.LandingPadLabel && LandingPad.LandingPadBlock) { LandingPads.erase(LandingPads.begin() + i); continue; @@ -1757,7 +1757,6 @@ void MachineModuleInfo::TidyLandingPads() { unsigned BeginLabel = MappedLabel(LandingPad.BeginLabels[j]); unsigned EndLabel = MappedLabel(LandingPad.EndLabels[j]); - if (!BeginLabel || !EndLabel) { LandingPad.BeginLabels.erase(LandingPad.BeginLabels.begin() + j); LandingPad.EndLabels.erase(LandingPad.EndLabels.begin() + j); diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp b/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp index bc336d20697..05a7a954d7f 100644 --- a/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp +++ b/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp @@ -2952,7 +2952,11 @@ void SelectionDAGLowering::LowerCallTo(Instruction &I, Args.push_back(Entry); } - if (ExceptionHandling && MMI && LandingPad) { + bool MarkTryRange = LandingPad || + // C++ requires special handling of 'nounwind' calls. + (Attrs && Attrs->paramHasAttr(0, ParamAttr::NoUnwind)); + + if (MarkTryRange && ExceptionHandling && MMI) { // Insert a label before the invoke call to mark the try range. This can be // used to detect deletion of the invoke via the MachineModuleInfo. BeginLabel = MMI->NextLabelID(); @@ -2969,7 +2973,7 @@ void SelectionDAGLowering::LowerCallTo(Instruction &I, setValue(&I, Result.first); DAG.setRoot(Result.second); - if (ExceptionHandling && MMI && LandingPad) { + if (MarkTryRange && ExceptionHandling && MMI) { // Insert a label at the end of the invoke call to mark the try range. This // can be used to detect deletion of the invoke via the MachineModuleInfo. EndLabel = MMI->NextLabelID();