--- /dev/null
+//===-- CodeGen/AsmPrinter/DwarfException.cpp - Dwarf Exception Impl ------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file contains support for writing dwarf exception info into asm files.
+//
+//===----------------------------------------------------------------------===//
+
+#include "DwarfException.h"
+#include "llvm/Module.h"
+#include "llvm/CodeGen/MachineModuleInfo.h"
+#include "llvm/CodeGen/MachineFrameInfo.h"
+#include "llvm/CodeGen/MachineLocation.h"
+#include "llvm/Support/Dwarf.h"
+#include "llvm/Support/Timer.h"
+#include "llvm/Support/raw_ostream.h"
+#include "llvm/Target/TargetAsmInfo.h"
+#include "llvm/Target/TargetRegisterInfo.h"
+#include "llvm/Target/TargetData.h"
+#include "llvm/Target/TargetFrameInfo.h"
+#include "llvm/Target/TargetOptions.h"
+#include "llvm/ADT/StringExtras.h"
+using namespace llvm;
+
+static TimerGroup &getDwarfTimerGroup() {
+ static TimerGroup DwarfTimerGroup("Dwarf Exception");
+ return DwarfTimerGroup;
+}
+
+void DwarfException::EmitCommonEHFrame(const Function *Personality,
+ unsigned Index) {
+ // Size and sign of stack growth.
+ int stackGrowth =
+ Asm->TM.getFrameInfo()->getStackGrowthDirection() ==
+ TargetFrameInfo::StackGrowsUp ?
+ TD->getPointerSize() : -TD->getPointerSize();
+
+ // Begin eh frame section.
+ Asm->SwitchToTextSection(TAI->getDwarfEHFrameSection());
+
+ if (!TAI->doesRequireNonLocalEHFrameLabel())
+ O << TAI->getEHGlobalPrefix();
+
+ O << "EH_frame" << Index << ":\n";
+ EmitLabel("section_eh_frame", Index);
+
+ // Define base labels.
+ EmitLabel("eh_frame_common", Index);
+
+ // Define the eh frame length.
+ EmitDifference("eh_frame_common_end", Index,
+ "eh_frame_common_begin", Index, true);
+ Asm->EOL("Length of Common Information Entry");
+
+ // EH frame header.
+ EmitLabel("eh_frame_common_begin", Index);
+ Asm->EmitInt32((int)0);
+ Asm->EOL("CIE Identifier Tag");
+ Asm->EmitInt8(dwarf::DW_CIE_VERSION);
+ Asm->EOL("CIE Version");
+
+ // The personality presence indicates that language specific information will
+ // show up in the eh frame.
+ Asm->EmitString(Personality ? "zPLR" : "zR");
+ Asm->EOL("CIE Augmentation");
+
+ // Round out reader.
+ Asm->EmitULEB128Bytes(1);
+ Asm->EOL("CIE Code Alignment Factor");
+ Asm->EmitSLEB128Bytes(stackGrowth);
+ Asm->EOL("CIE Data Alignment Factor");
+ Asm->EmitInt8(RI->getDwarfRegNum(RI->getRARegister(), true));
+ Asm->EOL("CIE Return Address Column");
+
+ // If there is a personality, we need to indicate the functions location.
+ if (Personality) {
+ Asm->EmitULEB128Bytes(7);
+ Asm->EOL("Augmentation Size");
+
+ if (TAI->getNeedsIndirectEncoding()) {
+ Asm->EmitInt8(dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4 |
+ dwarf::DW_EH_PE_indirect);
+ Asm->EOL("Personality (pcrel sdata4 indirect)");
+ } else {
+ Asm->EmitInt8(dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4);
+ Asm->EOL("Personality (pcrel sdata4)");
+ }
+
+ PrintRelDirective(true);
+ O << TAI->getPersonalityPrefix();
+ Asm->EmitExternalGlobal((const GlobalVariable *)(Personality));
+ O << TAI->getPersonalitySuffix();
+ if (strcmp(TAI->getPersonalitySuffix(), "+4@GOTPCREL"))
+ O << "-" << TAI->getPCSymbol();
+ Asm->EOL("Personality");
+
+ Asm->EmitInt8(dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4);
+ Asm->EOL("LSDA Encoding (pcrel sdata4)");
+
+ Asm->EmitInt8(dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4);
+ Asm->EOL("FDE Encoding (pcrel sdata4)");
+ } else {
+ Asm->EmitULEB128Bytes(1);
+ Asm->EOL("Augmentation Size");
+
+ Asm->EmitInt8(dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4);
+ Asm->EOL("FDE Encoding (pcrel sdata4)");
+ }
+
+ // Indicate locations of general callee saved registers in frame.
+ std::vector<MachineMove> Moves;
+ RI->getInitialFrameState(Moves);
+ EmitFrameMoves(NULL, 0, Moves, true);
+
+ // On Darwin the linker honors the alignment of eh_frame, which means it must
+ // be 8-byte on 64-bit targets to match what gcc does. Otherwise you get
+ // holes which confuse readers of eh_frame.
+ Asm->EmitAlignment(TD->getPointerSize() == sizeof(int32_t) ? 2 : 3,
+ 0, 0, false);
+ EmitLabel("eh_frame_common_end", Index);
+
+ Asm->EOL();
+}
+
+/// EmitEHFrame - Emit function exception frame information.
+///
+void DwarfException::EmitEHFrame(const FunctionEHFrameInfo &EHFrameInfo) {
+ assert(!EHFrameInfo.function->hasAvailableExternallyLinkage() &&
+ "Should not emit 'available externally' functions at all");
+
+ Function::LinkageTypes linkage = EHFrameInfo.function->getLinkage();
+ Asm->SwitchToTextSection(TAI->getDwarfEHFrameSection());
+
+ // Externally visible entry into the functions eh frame info. If the
+ // corresponding function is static, this should not be externally visible.
+ if (linkage != Function::InternalLinkage &&
+ linkage != Function::PrivateLinkage) {
+ if (const char *GlobalEHDirective = TAI->getGlobalEHDirective())
+ O << GlobalEHDirective << EHFrameInfo.FnName << "\n";
+ }
+
+ // If corresponding function is weak definition, this should be too.
+ if ((linkage == Function::WeakAnyLinkage ||
+ linkage == Function::WeakODRLinkage ||
+ linkage == Function::LinkOnceAnyLinkage ||
+ linkage == Function::LinkOnceODRLinkage) &&
+ TAI->getWeakDefDirective())
+ O << TAI->getWeakDefDirective() << EHFrameInfo.FnName << "\n";
+
+ // If there are no calls then you can't unwind. This may mean we can omit the
+ // EH Frame, but some environments do not handle weak absolute symbols. If
+ // UnwindTablesMandatory is set we cannot do this optimization; the unwind
+ // info is to be available for non-EH uses.
+ if (!EHFrameInfo.hasCalls &&
+ !UnwindTablesMandatory &&
+ ((linkage != Function::WeakAnyLinkage &&
+ linkage != Function::WeakODRLinkage &&
+ linkage != Function::LinkOnceAnyLinkage &&
+ linkage != Function::LinkOnceODRLinkage) ||
+ !TAI->getWeakDefDirective() ||
+ TAI->getSupportsWeakOmittedEHFrame())) {
+ O << EHFrameInfo.FnName << " = 0\n";
+ // This name has no connection to the function, so it might get
+ // dead-stripped when the function is not, erroneously. Prohibit
+ // dead-stripping unconditionally.
+ if (const char *UsedDirective = TAI->getUsedDirective())
+ O << UsedDirective << EHFrameInfo.FnName << "\n\n";
+ } else {
+ O << EHFrameInfo.FnName << ":\n";
+
+ // EH frame header.
+ EmitDifference("eh_frame_end", EHFrameInfo.Number,
+ "eh_frame_begin", EHFrameInfo.Number, true);
+ Asm->EOL("Length of Frame Information Entry");
+
+ EmitLabel("eh_frame_begin", EHFrameInfo.Number);
+
+ if (TAI->doesRequireNonLocalEHFrameLabel()) {
+ PrintRelDirective(true, true);
+ PrintLabelName("eh_frame_begin", EHFrameInfo.Number);
+
+ if (!TAI->isAbsoluteEHSectionOffsets())
+ O << "-EH_frame" << EHFrameInfo.PersonalityIndex;
+ } else {
+ EmitSectionOffset("eh_frame_begin", "eh_frame_common",
+ EHFrameInfo.Number, EHFrameInfo.PersonalityIndex,
+ true, true, false);
+ }
+
+ Asm->EOL("FDE CIE offset");
+
+ EmitReference("eh_func_begin", EHFrameInfo.Number, true, true);
+ Asm->EOL("FDE initial location");
+ EmitDifference("eh_func_end", EHFrameInfo.Number,
+ "eh_func_begin", EHFrameInfo.Number, true);
+ Asm->EOL("FDE address range");
+
+ // If there is a personality and landing pads then point to the language
+ // specific data area in the exception table.
+ if (EHFrameInfo.PersonalityIndex) {
+ Asm->EmitULEB128Bytes(4);
+ Asm->EOL("Augmentation size");
+
+ if (EHFrameInfo.hasLandingPads)
+ EmitReference("exception", EHFrameInfo.Number, true, true);
+ else
+ Asm->EmitInt32((int)0);
+ Asm->EOL("Language Specific Data Area");
+ } else {
+ Asm->EmitULEB128Bytes(0);
+ Asm->EOL("Augmentation size");
+ }
+
+ // Indicate locations of function specific callee saved registers in frame.
+ EmitFrameMoves("eh_func_begin", EHFrameInfo.Number, EHFrameInfo.Moves,
+ true);
+
+ // On Darwin the linker honors the alignment of eh_frame, which means it
+ // must be 8-byte on 64-bit targets to match what gcc does. Otherwise you
+ // get holes which confuse readers of eh_frame.
+ Asm->EmitAlignment(TD->getPointerSize() == sizeof(int32_t) ? 2 : 3,
+ 0, 0, false);
+ EmitLabel("eh_frame_end", EHFrameInfo.Number);
+
+ // If the function is marked used, this table should be also. We cannot
+ // make the mark unconditional in this case, since retaining the table also
+ // retains the function in this case, and there is code around that depends
+ // on unused functions (calling undefined externals) being dead-stripped to
+ // link correctly. Yes, there really is.
+ if (MMI->getUsedFunctions().count(EHFrameInfo.function))
+ if (const char *UsedDirective = TAI->getUsedDirective())
+ O << UsedDirective << EHFrameInfo.FnName << "\n\n";
+ }
+}
+
+/// EmitExceptionTable - Emit landing pads and actions.
+///
+/// The general organization of the table is complex, but the basic concepts are
+/// easy. First there is a header which describes the location and organization
+/// of the three components that follow.
+///
+/// 1. The landing pad site information describes the range of code covered by
+/// the try. In our case it's an accumulation of the ranges covered by the
+/// invokes in the try. There is also a reference to the landing pad that
+/// handles the exception once processed. Finally an index into the actions
+/// table.
+/// 2. The action table, in our case, is composed of pairs of type ids and next
+/// action offset. Starting with the action index from the landing pad
+/// site, each type Id is checked for a match to the current exception. If
+/// it matches then the exception and type id are passed on to the landing
+/// pad. Otherwise the next action is looked up. This chain is terminated
+/// with a next action of zero. If no type id is found the the frame is
+/// unwound and handling continues.
+/// 3. Type id table contains references to all the C++ typeinfo for all
+/// catches in the function. This tables is reversed indexed base 1.
+
+/// SharedTypeIds - How many leading type ids two landing pads have in common.
+unsigned DwarfException::SharedTypeIds(const LandingPadInfo *L,
+ const LandingPadInfo *R) {
+ const std::vector<int> &LIds = L->TypeIds, &RIds = R->TypeIds;
+ unsigned LSize = LIds.size(), RSize = RIds.size();
+ unsigned MinSize = LSize < RSize ? LSize : RSize;
+ unsigned Count = 0;
+
+ for (; Count != MinSize; ++Count)
+ if (LIds[Count] != RIds[Count])
+ return Count;
+
+ return Count;
+}
+
+/// PadLT - Order landing pads lexicographically by type id.
+bool DwarfException::PadLT(const LandingPadInfo *L, const LandingPadInfo *R) {
+ const std::vector<int> &LIds = L->TypeIds, &RIds = R->TypeIds;
+ unsigned LSize = LIds.size(), RSize = RIds.size();
+ unsigned MinSize = LSize < RSize ? LSize : RSize;
+
+ for (unsigned i = 0; i != MinSize; ++i)
+ if (LIds[i] != RIds[i])
+ return LIds[i] < RIds[i];
+
+ return LSize < RSize;
+}
+
+void DwarfException::EmitExceptionTable() {
+ const std::vector<GlobalVariable *> &TypeInfos = MMI->getTypeInfos();
+ const std::vector<unsigned> &FilterIds = MMI->getFilterIds();
+ const std::vector<LandingPadInfo> &PadInfos = MMI->getLandingPads();
+ if (PadInfos.empty()) return;
+
+ // Sort the landing pads in order of their type ids. This is used to fold
+ // duplicate actions.
+ SmallVector<const LandingPadInfo *, 64> LandingPads;
+ LandingPads.reserve(PadInfos.size());
+ for (unsigned i = 0, N = PadInfos.size(); i != N; ++i)
+ LandingPads.push_back(&PadInfos[i]);
+ std::sort(LandingPads.begin(), LandingPads.end(), PadLT);
+
+ // Negative type ids index into FilterIds, positive type ids index into
+ // TypeInfos. The value written for a positive type id is just the type id
+ // itself. For a negative type id, however, the value written is the
+ // (negative) byte offset of the corresponding FilterIds entry. The byte
+ // offset is usually equal to the type id, because the FilterIds entries are
+ // written using a variable width encoding which outputs one byte per entry as
+ // long as the value written is not too large, but can differ. This kind of
+ // complication does not occur for positive type ids because type infos are
+ // output using a fixed width encoding. FilterOffsets[i] holds the byte
+ // offset corresponding to FilterIds[i].
+ SmallVector<int, 16> FilterOffsets;
+ FilterOffsets.reserve(FilterIds.size());
+ int Offset = -1;
+ for(std::vector<unsigned>::const_iterator I = FilterIds.begin(),
+ E = FilterIds.end(); I != E; ++I) {
+ FilterOffsets.push_back(Offset);
+ Offset -= TargetAsmInfo::getULEB128Size(*I);
+ }
+
+ // Compute the actions table and gather the first action index for each
+ // landing pad site.
+ SmallVector<ActionEntry, 32> Actions;
+ SmallVector<unsigned, 64> FirstActions;
+ FirstActions.reserve(LandingPads.size());
+
+ int FirstAction = 0;
+ unsigned SizeActions = 0;
+ for (unsigned i = 0, N = LandingPads.size(); i != N; ++i) {
+ const LandingPadInfo *LP = LandingPads[i];
+ const std::vector<int> &TypeIds = LP->TypeIds;
+ const unsigned NumShared = i ? SharedTypeIds(LP, LandingPads[i-1]) : 0;
+ unsigned SizeSiteActions = 0;
+
+ if (NumShared < TypeIds.size()) {
+ unsigned SizeAction = 0;
+ ActionEntry *PrevAction = 0;
+
+ if (NumShared) {
+ const unsigned SizePrevIds = LandingPads[i-1]->TypeIds.size();
+ assert(Actions.size());
+ PrevAction = &Actions.back();
+ SizeAction = TargetAsmInfo::getSLEB128Size(PrevAction->NextAction) +
+ TargetAsmInfo::getSLEB128Size(PrevAction->ValueForTypeID);
+
+ for (unsigned j = NumShared; j != SizePrevIds; ++j) {
+ SizeAction -=
+ TargetAsmInfo::getSLEB128Size(PrevAction->ValueForTypeID);
+ SizeAction += -PrevAction->NextAction;
+ PrevAction = PrevAction->Previous;
+ }
+ }
+
+ // Compute the actions.
+ for (unsigned I = NumShared, M = TypeIds.size(); I != M; ++I) {
+ int TypeID = TypeIds[I];
+ assert(-1-TypeID < (int)FilterOffsets.size() && "Unknown filter id!");
+ int ValueForTypeID = TypeID < 0 ? FilterOffsets[-1 - TypeID] : TypeID;
+ unsigned SizeTypeID = TargetAsmInfo::getSLEB128Size(ValueForTypeID);
+
+ int NextAction = SizeAction ? -(SizeAction + SizeTypeID) : 0;
+ SizeAction = SizeTypeID + TargetAsmInfo::getSLEB128Size(NextAction);
+ SizeSiteActions += SizeAction;
+
+ ActionEntry Action = {ValueForTypeID, NextAction, PrevAction};
+ Actions.push_back(Action);
+
+ PrevAction = &Actions.back();
+ }
+
+ // Record the first action of the landing pad site.
+ FirstAction = SizeActions + SizeSiteActions - SizeAction + 1;
+ } // else identical - re-use previous FirstAction
+
+ FirstActions.push_back(FirstAction);
+
+ // Compute this sites contribution to size.
+ SizeActions += SizeSiteActions;
+ }
+
+ // 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<CallSiteEntry, 64> 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) {
+ unsigned BeginLabel = LandingPad->BeginLabels[j];
+ assert(!PadMap.count(BeginLabel) && "Duplicate landing pad labels!");
+ PadRange P = { i, j };
+ PadMap[BeginLabel] = P;
+ }
+ }
+
+ // 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;
+
+ // 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->isLabel()) {
+ SawPotentiallyThrowing |= MI->getDesc().isCall();
+ continue;
+ }
+
+ unsigned BeginLabel = MI->getOperand(0).getImm();
+ assert(BeginLabel && "Invalid label!");
+
+ // End of the previous try-range?
+ if (BeginLabel == LastLabel)
+ 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;
+ const LandingPadInfo *LandingPad = LandingPads[P.PadIndex];
+
+ assert(BeginLabel == LandingPad->BeginLabels[P.RangeIndex] &&
+ "Inconsistent landing pad map!");
+
+ // 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 (SawPotentiallyThrowing) {
+ CallSiteEntry Site = {LastLabel, BeginLabel, 0, 0};
+ CallSites.push_back(Site);
+ PreviousIsInvoke = false;
+ }
+
+ LastLabel = LandingPad->EndLabels[P.RangeIndex];
+ assert(BeginLabel && LastLabel && "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 (PreviousIsInvoke) {
+ CallSiteEntry &Prev = CallSites.back();
+ 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);
+ 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 (SawPotentiallyThrowing) {
+ CallSiteEntry Site = {LastLabel, 0, 0, 0};
+ CallSites.push_back(Site);
+ }
+
+ // Final tallies.
+
+ // Call sites.
+ const unsigned SiteStartSize = sizeof(int32_t); // DW_EH_PE_udata4
+ const unsigned SiteLengthSize = sizeof(int32_t); // DW_EH_PE_udata4
+ const unsigned LandingPadSize = sizeof(int32_t); // DW_EH_PE_udata4
+ unsigned SizeSites = CallSites.size() * (SiteStartSize +
+ SiteLengthSize +
+ LandingPadSize);
+ for (unsigned i = 0, e = CallSites.size(); i < e; ++i)
+ SizeSites += TargetAsmInfo::getULEB128Size(CallSites[i].Action);
+
+ // Type infos.
+ const unsigned TypeInfoSize = TD->getPointerSize(); // DW_EH_PE_absptr
+ unsigned SizeTypes = TypeInfos.size() * TypeInfoSize;
+
+ unsigned TypeOffset = sizeof(int8_t) + // Call site format
+ TargetAsmInfo::getULEB128Size(SizeSites) + // Call-site table length
+ SizeSites + SizeActions + SizeTypes;
+
+ unsigned TotalSize = sizeof(int8_t) + // LPStart format
+ sizeof(int8_t) + // TType format
+ TargetAsmInfo::getULEB128Size(TypeOffset) + // TType base offset
+ TypeOffset;
+
+ unsigned SizeAlign = (4 - TotalSize) & 3;
+
+ // Begin the exception table.
+ Asm->SwitchToDataSection(TAI->getDwarfExceptionSection());
+ Asm->EmitAlignment(2, 0, 0, false);
+ O << "GCC_except_table" << SubprogramCount << ":\n";
+
+ for (unsigned i = 0; i != SizeAlign; ++i) {
+ Asm->EmitInt8(0);
+ Asm->EOL("Padding");
+ }
+
+ EmitLabel("exception", SubprogramCount);
+
+ // Emit the header.
+ Asm->EmitInt8(dwarf::DW_EH_PE_omit);
+ Asm->EOL("LPStart format (DW_EH_PE_omit)");
+ Asm->EmitInt8(dwarf::DW_EH_PE_absptr);
+ Asm->EOL("TType format (DW_EH_PE_absptr)");
+ Asm->EmitULEB128Bytes(TypeOffset);
+ Asm->EOL("TType base offset");
+ Asm->EmitInt8(dwarf::DW_EH_PE_udata4);
+ Asm->EOL("Call site format (DW_EH_PE_udata4)");
+ Asm->EmitULEB128Bytes(SizeSites);
+ Asm->EOL("Call-site table length");
+
+ // Emit the landing pad site information.
+ for (unsigned i = 0; i < CallSites.size(); ++i) {
+ CallSiteEntry &S = CallSites[i];
+ const char *BeginTag;
+ unsigned BeginNumber;
+
+ if (!S.BeginLabel) {
+ BeginTag = "eh_func_begin";
+ BeginNumber = SubprogramCount;
+ } else {
+ BeginTag = "label";
+ BeginNumber = S.BeginLabel;
+ }
+
+ EmitSectionOffset(BeginTag, "eh_func_begin", BeginNumber, SubprogramCount,
+ true, true);
+ Asm->EOL("Region start");
+
+ if (!S.EndLabel)
+ EmitDifference("eh_func_end", SubprogramCount, BeginTag, BeginNumber,
+ true);
+ else
+ EmitDifference("label", S.EndLabel, BeginTag, BeginNumber, true);
+
+ Asm->EOL("Region length");
+
+ if (!S.PadLabel)
+ Asm->EmitInt32(0);
+ else
+ EmitSectionOffset("label", "eh_func_begin", S.PadLabel, SubprogramCount,
+ true, true);
+
+ Asm->EOL("Landing pad");
+
+ Asm->EmitULEB128Bytes(S.Action);
+ Asm->EOL("Action");
+ }
+
+ // Emit the actions.
+ for (unsigned I = 0, N = Actions.size(); I != N; ++I) {
+ ActionEntry &Action = Actions[I];
+
+ Asm->EmitSLEB128Bytes(Action.ValueForTypeID);
+ Asm->EOL("TypeInfo index");
+ Asm->EmitSLEB128Bytes(Action.NextAction);
+ Asm->EOL("Next action");
+ }
+
+ // Emit the type ids.
+ for (unsigned M = TypeInfos.size(); M; --M) {
+ GlobalVariable *GV = TypeInfos[M - 1];
+ PrintRelDirective();
+
+ if (GV) {
+ std::string GLN;
+ O << Asm->getGlobalLinkName(GV, GLN);
+ } else {
+ O << "0";
+ }
+
+ Asm->EOL("TypeInfo");
+ }
+
+ // Emit the filter typeids.
+ for (unsigned j = 0, M = FilterIds.size(); j < M; ++j) {
+ unsigned TypeID = FilterIds[j];
+ Asm->EmitULEB128Bytes(TypeID);
+ Asm->EOL("Filter TypeInfo index");
+ }
+
+ Asm->EmitAlignment(2, 0, 0, false);
+}
+
+ //===--------------------------------------------------------------------===//
+ // Main entry points.
+ //
+DwarfException::DwarfException(raw_ostream &OS, AsmPrinter *A,
+ const TargetAsmInfo *T)
+ : Dwarf(OS, A, T, "eh"), shouldEmitTable(false), shouldEmitMoves(false),
+ shouldEmitTableModule(false), shouldEmitMovesModule(false),
+ ExceptionTimer(0) {
+ if (TimePassesIsEnabled)
+ ExceptionTimer = new Timer("Dwarf Exception Writer",
+ getDwarfTimerGroup());
+}
+
+DwarfException::~DwarfException() {
+ delete ExceptionTimer;
+}
+
+/// EndModule - Emit all exception information that should come after the
+/// content.
+void DwarfException::EndModule() {
+ if (TimePassesIsEnabled)
+ ExceptionTimer->startTimer();
+
+ if (shouldEmitMovesModule || shouldEmitTableModule) {
+ const std::vector<Function *> Personalities = MMI->getPersonalities();
+ for (unsigned i = 0; i < Personalities.size(); ++i)
+ EmitCommonEHFrame(Personalities[i], i);
+
+ for (std::vector<FunctionEHFrameInfo>::iterator I = EHFrames.begin(),
+ E = EHFrames.end(); I != E; ++I)
+ EmitEHFrame(*I);
+ }
+
+ if (TimePassesIsEnabled)
+ ExceptionTimer->stopTimer();
+}
+
+/// BeginFunction - Gather pre-function exception information. Assumes being
+/// emitted immediately after the function entry point.
+void DwarfException::BeginFunction(MachineFunction *MF) {
+ if (TimePassesIsEnabled)
+ ExceptionTimer->startTimer();
+
+ this->MF = MF;
+ shouldEmitTable = shouldEmitMoves = false;
+
+ if (MMI && TAI->doesSupportExceptionHandling()) {
+ // Map all labels and get rid of any dead landing pads.
+ MMI->TidyLandingPads();
+
+ // If any landing pads survive, we need an EH table.
+ if (MMI->getLandingPads().size())
+ shouldEmitTable = true;
+
+ // See if we need frame move info.
+ if (!MF->getFunction()->doesNotThrow() || UnwindTablesMandatory)
+ shouldEmitMoves = true;
+
+ if (shouldEmitMoves || shouldEmitTable)
+ // Assumes in correct section after the entry point.
+ EmitLabel("eh_func_begin", ++SubprogramCount);
+ }
+
+ shouldEmitTableModule |= shouldEmitTable;
+ shouldEmitMovesModule |= shouldEmitMoves;
+
+ if (TimePassesIsEnabled)
+ ExceptionTimer->stopTimer();
+}
+
+/// EndFunction - Gather and emit post-function exception information.
+///
+void DwarfException::EndFunction() {
+ if (TimePassesIsEnabled)
+ ExceptionTimer->startTimer();
+
+ if (shouldEmitMoves || shouldEmitTable) {
+ EmitLabel("eh_func_end", SubprogramCount);
+ EmitExceptionTable();
+
+ // Save EH frame information
+ std::string Name;
+ EHFrames.push_back(
+ FunctionEHFrameInfo(getAsm()->getCurrentFunctionEHName(MF, Name),
+ SubprogramCount,
+ MMI->getPersonalityIndex(),
+ MF->getFrameInfo()->hasCalls(),
+ !MMI->getLandingPads().empty(),
+ MMI->getFrameMoves(),
+ MF->getFunction()));
+ }
+
+ if (TimePassesIsEnabled)
+ ExceptionTimer->stopTimer();
+}
--- /dev/null
+//===-- DwarfException.h - Dwarf Exception Framework -----------*- C++ -*--===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file contains support for writing dwarf exception info into asm files.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef DWARFEXCEPTION_H__
+#define DWARFEXCEPTION_H__
+
+#include "DIE.h"
+#include "DwarfPrinter.h"
+#include "llvm/CodeGen/AsmPrinter.h"
+#include "llvm/ADT/DenseMap.h"
+#include <string>
+
+namespace llvm {
+
+struct LandingPadInfo;
+class MachineModuleInfo;
+class TargetAsmInfo;
+class Timer;
+class raw_ostream;
+
+//===----------------------------------------------------------------------===//
+/// DwarfException - Emits Dwarf exception handling directives.
+///
+class VISIBILITY_HIDDEN DwarfException : public Dwarf {
+ struct FunctionEHFrameInfo {
+ std::string FnName;
+ unsigned Number;
+ unsigned PersonalityIndex;
+ bool hasCalls;
+ bool hasLandingPads;
+ std::vector<MachineMove> Moves;
+ const Function * function;
+
+ FunctionEHFrameInfo(const std::string &FN, unsigned Num, unsigned P,
+ bool hC, bool hL,
+ const std::vector<MachineMove> &M,
+ const Function *f):
+ FnName(FN), Number(Num), PersonalityIndex(P),
+ hasCalls(hC), hasLandingPads(hL), Moves(M), function (f) { }
+ };
+
+ std::vector<FunctionEHFrameInfo> EHFrames;
+
+ /// shouldEmitTable - Per-function flag to indicate if EH tables should
+ /// be emitted.
+ bool shouldEmitTable;
+
+ /// shouldEmitMoves - Per-function flag to indicate if frame moves info
+ /// should be emitted.
+ bool shouldEmitMoves;
+
+ /// shouldEmitTableModule - Per-module flag to indicate if EH tables
+ /// should be emitted.
+ bool shouldEmitTableModule;
+
+ /// shouldEmitFrameModule - Per-module flag to indicate if frame moves
+ /// should be emitted.
+ bool shouldEmitMovesModule;
+
+ /// ExceptionTimer - Timer for the Dwarf exception writer.
+ Timer *ExceptionTimer;
+
+ /// EmitCommonEHFrame - Emit the common eh unwind frame.
+ ///
+ void EmitCommonEHFrame(const Function *Personality, unsigned Index);
+
+ /// EmitEHFrame - Emit function exception frame information.
+ ///
+ void EmitEHFrame(const FunctionEHFrameInfo &EHFrameInfo);
+
+ /// EmitExceptionTable - Emit landing pads and actions.
+ ///
+ /// The general organization of the table is complex, but the basic concepts
+ /// are easy. First there is a header which describes the location and
+ /// organization of the three components that follow.
+ /// 1. The landing pad site information describes the range of code covered
+ /// by the try. In our case it's an accumulation of the ranges covered
+ /// by the invokes in the try. There is also a reference to the landing
+ /// pad that handles the exception once processed. Finally an index into
+ /// the actions table.
+ /// 2. The action table, in our case, is composed of pairs of type ids
+ /// and next action offset. Starting with the action index from the
+ /// landing pad site, each type Id is checked for a match to the current
+ /// exception. If it matches then the exception and type id are passed
+ /// on to the landing pad. Otherwise the next action is looked up. This
+ /// chain is terminated with a next action of zero. If no type id is
+ /// found the the frame is unwound and handling continues.
+ /// 3. Type id table contains references to all the C++ typeinfo for all
+ /// catches in the function. This tables is reversed indexed base 1.
+
+ /// SharedTypeIds - How many leading type ids two landing pads have in common.
+ static unsigned SharedTypeIds(const LandingPadInfo *L,
+ const LandingPadInfo *R);
+
+ /// PadLT - Order landing pads lexicographically by type id.
+ static bool PadLT(const LandingPadInfo *L, const LandingPadInfo *R);
+
+ struct KeyInfo {
+ static inline unsigned getEmptyKey() { return -1U; }
+ static inline unsigned getTombstoneKey() { return -2U; }
+ static unsigned getHashValue(const unsigned &Key) { return Key; }
+ static bool isEqual(unsigned LHS, unsigned RHS) { return LHS == RHS; }
+ static bool isPod() { return true; }
+ };
+
+ /// ActionEntry - Structure describing an entry in the actions table.
+ struct ActionEntry {
+ int ValueForTypeID; // The value to write - may not be equal to the type id.
+ int NextAction;
+ struct ActionEntry *Previous;
+ };
+
+ /// PadRange - Structure holding a try-range and the associated landing pad.
+ struct PadRange {
+ // The index of the landing pad.
+ unsigned PadIndex;
+ // The index of the begin and end labels in the landing pad's label lists.
+ unsigned RangeIndex;
+ };
+
+ typedef DenseMap<unsigned, PadRange, KeyInfo> RangeMapType;
+
+ /// 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;
+ };
+
+ void EmitExceptionTable();
+
+public:
+ //===--------------------------------------------------------------------===//
+ // Main entry points.
+ //
+ DwarfException(raw_ostream &OS, AsmPrinter *A, const TargetAsmInfo *T);
+ virtual ~DwarfException();
+
+ /// SetModuleInfo - Set machine module information when it's known that pass
+ /// manager has created it. Set by the target AsmPrinter.
+ void SetModuleInfo(MachineModuleInfo *mmi) {
+ MMI = mmi;
+ }
+
+ /// BeginModule - Emit all exception information that should come prior to the
+ /// content.
+ void BeginModule(Module *M) {
+ this->M = M;
+ }
+
+ /// EndModule - Emit all exception information that should come after the
+ /// content.
+ void EndModule();
+
+ /// BeginFunction - Gather pre-function exception information. Assumes being
+ /// emitted immediately after the function entry point.
+ void BeginFunction(MachineFunction *MF);
+
+ /// EndFunction - Gather and emit post-function exception information.
+ void EndFunction();
+};
+
+} // End of namespace llvm
+
+#endif
#include "llvm/CodeGen/DwarfWriter.h"
#include "DIE.h"
+#include "DwarfException.h"
#include "DwarfPrinter.h"
#include "llvm/Module.h"
#include "llvm/DerivedTypes.h"
//===----------------------------------------------------------------------===//
/// CompileUnit - This dwarf writer support class manages information associate
/// with a source file.
-class CompileUnit {
+class VISIBILITY_HIDDEN CompileUnit {
/// ID - File identifier for source.
///
unsigned ID;
//===----------------------------------------------------------------------===//
/// SrcLineInfo - This class is used to record source line correspondence.
///
-class SrcLineInfo {
+class VISIBILITY_HIDDEN SrcLineInfo {
unsigned Line; // Source line number.
unsigned Column; // Source column.
unsigned SourceID; // Source ID number.
//===----------------------------------------------------------------------===//
/// DbgVariable - This class is used to track local variable information.
///
-class DbgVariable {
+class VISIBILITY_HIDDEN DbgVariable {
DIVariable Var; // Variable Descriptor.
unsigned FrameIndex; // Variable frame index.
public:
/// DbgScope - This class is used to track scope information.
///
class DbgConcreteScope;
-class DbgScope {
+class VISIBILITY_HIDDEN DbgScope {
DbgScope *Parent; // Parent to this scope.
DIDescriptor Desc; // Debug info descriptor for scope.
// Either subprogram or block.
/// DbgConcreteScope - This class is used to track a scope that holds concrete
/// instance information.
///
-class DbgConcreteScope : public DbgScope {
+class VISIBILITY_HIDDEN DbgConcreteScope : public DbgScope {
CompileUnit *Unit;
DIE *Die; // Debug info for this concrete scope.
public:
//===----------------------------------------------------------------------===//
/// DwarfDebug - Emits Dwarf debug directives.
///
-class DwarfDebug : public Dwarf {
+class VISIBILITY_HIDDEN DwarfDebug : public Dwarf {
//===--------------------------------------------------------------------===//
// Attributes used to construct specific Dwarf sections.
//
}
};
-//===----------------------------------------------------------------------===//
-/// DwarfException - Emits Dwarf exception handling directives.
-///
-class DwarfException : public Dwarf {
- struct FunctionEHFrameInfo {
- std::string FnName;
- unsigned Number;
- unsigned PersonalityIndex;
- bool hasCalls;
- bool hasLandingPads;
- std::vector<MachineMove> Moves;
- const Function * function;
-
- FunctionEHFrameInfo(const std::string &FN, unsigned Num, unsigned P,
- bool hC, bool hL,
- const std::vector<MachineMove> &M,
- const Function *f):
- FnName(FN), Number(Num), PersonalityIndex(P),
- hasCalls(hC), hasLandingPads(hL), Moves(M), function (f) { }
- };
-
- std::vector<FunctionEHFrameInfo> EHFrames;
-
- /// shouldEmitTable - Per-function flag to indicate if EH tables should
- /// be emitted.
- bool shouldEmitTable;
-
- /// shouldEmitMoves - Per-function flag to indicate if frame moves info
- /// should be emitted.
- bool shouldEmitMoves;
-
- /// shouldEmitTableModule - Per-module flag to indicate if EH tables
- /// should be emitted.
- bool shouldEmitTableModule;
-
- /// shouldEmitFrameModule - Per-module flag to indicate if frame moves
- /// should be emitted.
- bool shouldEmitMovesModule;
-
- /// ExceptionTimer - Timer for the Dwarf exception writer.
- Timer *ExceptionTimer;
-
- /// EmitCommonEHFrame - Emit the common eh unwind frame.
- ///
- void EmitCommonEHFrame(const Function *Personality, unsigned Index) {
- // Size and sign of stack growth.
- int stackGrowth =
- Asm->TM.getFrameInfo()->getStackGrowthDirection() ==
- TargetFrameInfo::StackGrowsUp ?
- TD->getPointerSize() : -TD->getPointerSize();
-
- // Begin eh frame section.
- Asm->SwitchToTextSection(TAI->getDwarfEHFrameSection());
-
- if (!TAI->doesRequireNonLocalEHFrameLabel())
- O << TAI->getEHGlobalPrefix();
- O << "EH_frame" << Index << ":\n";
- EmitLabel("section_eh_frame", Index);
-
- // Define base labels.
- EmitLabel("eh_frame_common", Index);
-
- // Define the eh frame length.
- EmitDifference("eh_frame_common_end", Index,
- "eh_frame_common_begin", Index, true);
- Asm->EOL("Length of Common Information Entry");
-
- // EH frame header.
- EmitLabel("eh_frame_common_begin", Index);
- Asm->EmitInt32((int)0);
- Asm->EOL("CIE Identifier Tag");
- Asm->EmitInt8(DW_CIE_VERSION);
- Asm->EOL("CIE Version");
-
- // The personality presence indicates that language specific information
- // will show up in the eh frame.
- Asm->EmitString(Personality ? "zPLR" : "zR");
- Asm->EOL("CIE Augmentation");
-
- // Round out reader.
- Asm->EmitULEB128Bytes(1);
- Asm->EOL("CIE Code Alignment Factor");
- Asm->EmitSLEB128Bytes(stackGrowth);
- Asm->EOL("CIE Data Alignment Factor");
- Asm->EmitInt8(RI->getDwarfRegNum(RI->getRARegister(), true));
- Asm->EOL("CIE Return Address Column");
-
- // If there is a personality, we need to indicate the functions location.
- if (Personality) {
- Asm->EmitULEB128Bytes(7);
- Asm->EOL("Augmentation Size");
-
- if (TAI->getNeedsIndirectEncoding()) {
- Asm->EmitInt8(DW_EH_PE_pcrel | DW_EH_PE_sdata4 | DW_EH_PE_indirect);
- Asm->EOL("Personality (pcrel sdata4 indirect)");
- } else {
- Asm->EmitInt8(DW_EH_PE_pcrel | DW_EH_PE_sdata4);
- Asm->EOL("Personality (pcrel sdata4)");
- }
-
- PrintRelDirective(true);
- O << TAI->getPersonalityPrefix();
- Asm->EmitExternalGlobal((const GlobalVariable *)(Personality));
- O << TAI->getPersonalitySuffix();
- if (strcmp(TAI->getPersonalitySuffix(), "+4@GOTPCREL"))
- O << "-" << TAI->getPCSymbol();
- Asm->EOL("Personality");
-
- Asm->EmitInt8(DW_EH_PE_pcrel | DW_EH_PE_sdata4);
- Asm->EOL("LSDA Encoding (pcrel sdata4)");
-
- Asm->EmitInt8(DW_EH_PE_pcrel | DW_EH_PE_sdata4);
- Asm->EOL("FDE Encoding (pcrel sdata4)");
- } else {
- Asm->EmitULEB128Bytes(1);
- Asm->EOL("Augmentation Size");
-
- Asm->EmitInt8(DW_EH_PE_pcrel | DW_EH_PE_sdata4);
- Asm->EOL("FDE Encoding (pcrel sdata4)");
- }
-
- // Indicate locations of general callee saved registers in frame.
- std::vector<MachineMove> Moves;
- RI->getInitialFrameState(Moves);
- EmitFrameMoves(NULL, 0, Moves, true);
-
- // On Darwin the linker honors the alignment of eh_frame, which means it
- // must be 8-byte on 64-bit targets to match what gcc does. Otherwise
- // you get holes which confuse readers of eh_frame.
- Asm->EmitAlignment(TD->getPointerSize() == sizeof(int32_t) ? 2 : 3,
- 0, 0, false);
- EmitLabel("eh_frame_common_end", Index);
-
- Asm->EOL();
- }
-
- /// EmitEHFrame - Emit function exception frame information.
- ///
- void EmitEHFrame(const FunctionEHFrameInfo &EHFrameInfo) {
- Function::LinkageTypes linkage = EHFrameInfo.function->getLinkage();
-
- assert(!EHFrameInfo.function->hasAvailableExternallyLinkage() &&
- "Should not emit 'available externally' functions at all");
-
- Asm->SwitchToTextSection(TAI->getDwarfEHFrameSection());
-
- // Externally visible entry into the functions eh frame info.
- // If the corresponding function is static, this should not be
- // externally visible.
- if (linkage != Function::InternalLinkage &&
- linkage != Function::PrivateLinkage) {
- if (const char *GlobalEHDirective = TAI->getGlobalEHDirective())
- O << GlobalEHDirective << EHFrameInfo.FnName << "\n";
- }
-
- // If corresponding function is weak definition, this should be too.
- if ((linkage == Function::WeakAnyLinkage ||
- linkage == Function::WeakODRLinkage ||
- linkage == Function::LinkOnceAnyLinkage ||
- linkage == Function::LinkOnceODRLinkage) &&
- TAI->getWeakDefDirective())
- O << TAI->getWeakDefDirective() << EHFrameInfo.FnName << "\n";
-
- // If there are no calls then you can't unwind. This may mean we can
- // omit the EH Frame, but some environments do not handle weak absolute
- // symbols.
- // If UnwindTablesMandatory is set we cannot do this optimization; the
- // unwind info is to be available for non-EH uses.
- if (!EHFrameInfo.hasCalls &&
- !UnwindTablesMandatory &&
- ((linkage != Function::WeakAnyLinkage &&
- linkage != Function::WeakODRLinkage &&
- linkage != Function::LinkOnceAnyLinkage &&
- linkage != Function::LinkOnceODRLinkage) ||
- !TAI->getWeakDefDirective() ||
- TAI->getSupportsWeakOmittedEHFrame()))
- {
- O << EHFrameInfo.FnName << " = 0\n";
- // This name has no connection to the function, so it might get
- // dead-stripped when the function is not, erroneously. Prohibit
- // dead-stripping unconditionally.
- if (const char *UsedDirective = TAI->getUsedDirective())
- O << UsedDirective << EHFrameInfo.FnName << "\n\n";
- } else {
- O << EHFrameInfo.FnName << ":\n";
-
- // EH frame header.
- EmitDifference("eh_frame_end", EHFrameInfo.Number,
- "eh_frame_begin", EHFrameInfo.Number, true);
- Asm->EOL("Length of Frame Information Entry");
-
- EmitLabel("eh_frame_begin", EHFrameInfo.Number);
-
- if (TAI->doesRequireNonLocalEHFrameLabel()) {
- PrintRelDirective(true, true);
- PrintLabelName("eh_frame_begin", EHFrameInfo.Number);
-
- if (!TAI->isAbsoluteEHSectionOffsets())
- O << "-EH_frame" << EHFrameInfo.PersonalityIndex;
- } else {
- EmitSectionOffset("eh_frame_begin", "eh_frame_common",
- EHFrameInfo.Number, EHFrameInfo.PersonalityIndex,
- true, true, false);
- }
-
- Asm->EOL("FDE CIE offset");
-
- EmitReference("eh_func_begin", EHFrameInfo.Number, true, true);
- Asm->EOL("FDE initial location");
- EmitDifference("eh_func_end", EHFrameInfo.Number,
- "eh_func_begin", EHFrameInfo.Number, true);
- Asm->EOL("FDE address range");
-
- // If there is a personality and landing pads then point to the language
- // specific data area in the exception table.
- if (EHFrameInfo.PersonalityIndex) {
- Asm->EmitULEB128Bytes(4);
- Asm->EOL("Augmentation size");
-
- if (EHFrameInfo.hasLandingPads)
- EmitReference("exception", EHFrameInfo.Number, true, true);
- else
- Asm->EmitInt32((int)0);
- Asm->EOL("Language Specific Data Area");
- } else {
- Asm->EmitULEB128Bytes(0);
- Asm->EOL("Augmentation size");
- }
-
- // Indicate locations of function specific callee saved registers in
- // frame.
- EmitFrameMoves("eh_func_begin", EHFrameInfo.Number, EHFrameInfo.Moves,
- true);
-
- // On Darwin the linker honors the alignment of eh_frame, which means it
- // must be 8-byte on 64-bit targets to match what gcc does. Otherwise
- // you get holes which confuse readers of eh_frame.
- Asm->EmitAlignment(TD->getPointerSize() == sizeof(int32_t) ? 2 : 3,
- 0, 0, false);
- EmitLabel("eh_frame_end", EHFrameInfo.Number);
-
- // If the function is marked used, this table should be also. We cannot
- // make the mark unconditional in this case, since retaining the table
- // also retains the function in this case, and there is code around
- // that depends on unused functions (calling undefined externals) being
- // dead-stripped to link correctly. Yes, there really is.
- if (MMI->getUsedFunctions().count(EHFrameInfo.function))
- if (const char *UsedDirective = TAI->getUsedDirective())
- O << UsedDirective << EHFrameInfo.FnName << "\n\n";
- }
- }
-
- /// EmitExceptionTable - Emit landing pads and actions.
- ///
- /// The general organization of the table is complex, but the basic concepts
- /// are easy. First there is a header which describes the location and
- /// organization of the three components that follow.
- /// 1. The landing pad site information describes the range of code covered
- /// by the try. In our case it's an accumulation of the ranges covered
- /// by the invokes in the try. There is also a reference to the landing
- /// pad that handles the exception once processed. Finally an index into
- /// the actions table.
- /// 2. The action table, in our case, is composed of pairs of type ids
- /// and next action offset. Starting with the action index from the
- /// landing pad site, each type Id is checked for a match to the current
- /// exception. If it matches then the exception and type id are passed
- /// on to the landing pad. Otherwise the next action is looked up. This
- /// chain is terminated with a next action of zero. If no type id is
- /// found the the frame is unwound and handling continues.
- /// 3. Type id table contains references to all the C++ typeinfo for all
- /// catches in the function. This tables is reversed indexed base 1.
-
- /// SharedTypeIds - How many leading type ids two landing pads have in common.
- static unsigned SharedTypeIds(const LandingPadInfo *L,
- const LandingPadInfo *R) {
- const std::vector<int> &LIds = L->TypeIds, &RIds = R->TypeIds;
- unsigned LSize = LIds.size(), RSize = RIds.size();
- unsigned MinSize = LSize < RSize ? LSize : RSize;
- unsigned Count = 0;
-
- for (; Count != MinSize; ++Count)
- if (LIds[Count] != RIds[Count])
- return Count;
-
- return Count;
- }
-
- /// PadLT - Order landing pads lexicographically by type id.
- static bool PadLT(const LandingPadInfo *L, const LandingPadInfo *R) {
- const std::vector<int> &LIds = L->TypeIds, &RIds = R->TypeIds;
- unsigned LSize = LIds.size(), RSize = RIds.size();
- unsigned MinSize = LSize < RSize ? LSize : RSize;
-
- for (unsigned i = 0; i != MinSize; ++i)
- if (LIds[i] != RIds[i])
- return LIds[i] < RIds[i];
-
- return LSize < RSize;
- }
-
- struct KeyInfo {
- static inline unsigned getEmptyKey() { return -1U; }
- static inline unsigned getTombstoneKey() { return -2U; }
- static unsigned getHashValue(const unsigned &Key) { return Key; }
- static bool isEqual(unsigned LHS, unsigned RHS) { return LHS == RHS; }
- static bool isPod() { return true; }
- };
-
- /// ActionEntry - Structure describing an entry in the actions table.
- struct ActionEntry {
- int ValueForTypeID; // The value to write - may not be equal to the type id.
- int NextAction;
- struct ActionEntry *Previous;
- };
-
- /// PadRange - Structure holding a try-range and the associated landing pad.
- struct PadRange {
- // The index of the landing pad.
- unsigned PadIndex;
- // The index of the begin and end labels in the landing pad's label lists.
- unsigned RangeIndex;
- };
-
- typedef DenseMap<unsigned, PadRange, KeyInfo> RangeMapType;
-
- /// 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;
- };
-
- void EmitExceptionTable() {
- const std::vector<GlobalVariable *> &TypeInfos = MMI->getTypeInfos();
- const std::vector<unsigned> &FilterIds = MMI->getFilterIds();
- const std::vector<LandingPadInfo> &PadInfos = MMI->getLandingPads();
- if (PadInfos.empty()) return;
-
- // Sort the landing pads in order of their type ids. This is used to fold
- // duplicate actions.
- SmallVector<const LandingPadInfo *, 64> LandingPads;
- LandingPads.reserve(PadInfos.size());
- for (unsigned i = 0, N = PadInfos.size(); i != N; ++i)
- LandingPads.push_back(&PadInfos[i]);
- std::sort(LandingPads.begin(), LandingPads.end(), PadLT);
-
- // Negative type ids index into FilterIds, positive type ids index into
- // TypeInfos. The value written for a positive type id is just the type
- // id itself. For a negative type id, however, the value written is the
- // (negative) byte offset of the corresponding FilterIds entry. The byte
- // offset is usually equal to the type id, because the FilterIds entries
- // are written using a variable width encoding which outputs one byte per
- // entry as long as the value written is not too large, but can differ.
- // This kind of complication does not occur for positive type ids because
- // type infos are output using a fixed width encoding.
- // FilterOffsets[i] holds the byte offset corresponding to FilterIds[i].
- SmallVector<int, 16> FilterOffsets;
- FilterOffsets.reserve(FilterIds.size());
- int Offset = -1;
- for(std::vector<unsigned>::const_iterator I = FilterIds.begin(),
- E = FilterIds.end(); I != E; ++I) {
- FilterOffsets.push_back(Offset);
- Offset -= TargetAsmInfo::getULEB128Size(*I);
- }
-
- // Compute the actions table and gather the first action index for each
- // landing pad site.
- SmallVector<ActionEntry, 32> Actions;
- SmallVector<unsigned, 64> FirstActions;
- FirstActions.reserve(LandingPads.size());
-
- int FirstAction = 0;
- unsigned SizeActions = 0;
- for (unsigned i = 0, N = LandingPads.size(); i != N; ++i) {
- const LandingPadInfo *LP = LandingPads[i];
- const std::vector<int> &TypeIds = LP->TypeIds;
- const unsigned NumShared = i ? SharedTypeIds(LP, LandingPads[i-1]) : 0;
- unsigned SizeSiteActions = 0;
-
- if (NumShared < TypeIds.size()) {
- unsigned SizeAction = 0;
- ActionEntry *PrevAction = 0;
-
- if (NumShared) {
- const unsigned SizePrevIds = LandingPads[i-1]->TypeIds.size();
- assert(Actions.size());
- PrevAction = &Actions.back();
- SizeAction = TargetAsmInfo::getSLEB128Size(PrevAction->NextAction) +
- TargetAsmInfo::getSLEB128Size(PrevAction->ValueForTypeID);
- for (unsigned j = NumShared; j != SizePrevIds; ++j) {
- SizeAction -=
- TargetAsmInfo::getSLEB128Size(PrevAction->ValueForTypeID);
- SizeAction += -PrevAction->NextAction;
- PrevAction = PrevAction->Previous;
- }
- }
-
- // Compute the actions.
- for (unsigned I = NumShared, M = TypeIds.size(); I != M; ++I) {
- int TypeID = TypeIds[I];
- assert(-1-TypeID < (int)FilterOffsets.size() && "Unknown filter id!");
- int ValueForTypeID = TypeID < 0 ? FilterOffsets[-1 - TypeID] : TypeID;
- unsigned SizeTypeID = TargetAsmInfo::getSLEB128Size(ValueForTypeID);
-
- int NextAction = SizeAction ? -(SizeAction + SizeTypeID) : 0;
- SizeAction = SizeTypeID + TargetAsmInfo::getSLEB128Size(NextAction);
- SizeSiteActions += SizeAction;
-
- ActionEntry Action = {ValueForTypeID, NextAction, PrevAction};
- Actions.push_back(Action);
-
- PrevAction = &Actions.back();
- }
-
- // Record the first action of the landing pad site.
- FirstAction = SizeActions + SizeSiteActions - SizeAction + 1;
- } // else identical - re-use previous FirstAction
-
- FirstActions.push_back(FirstAction);
-
- // Compute this sites contribution to size.
- SizeActions += SizeSiteActions;
- }
-
- // 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<CallSiteEntry, 64> 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) {
- unsigned BeginLabel = LandingPad->BeginLabels[j];
- assert(!PadMap.count(BeginLabel) && "Duplicate landing pad labels!");
- PadRange P = { i, j };
- PadMap[BeginLabel] = P;
- }
- }
-
- // 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;
-
- // 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->isLabel()) {
- SawPotentiallyThrowing |= MI->getDesc().isCall();
- continue;
- }
-
- unsigned BeginLabel = MI->getOperand(0).getImm();
- assert(BeginLabel && "Invalid label!");
-
- // End of the previous try-range?
- if (BeginLabel == LastLabel)
- 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;
- const LandingPadInfo *LandingPad = LandingPads[P.PadIndex];
-
- assert(BeginLabel == LandingPad->BeginLabels[P.RangeIndex] &&
- "Inconsistent landing pad map!");
-
- // 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 (SawPotentiallyThrowing) {
- CallSiteEntry Site = {LastLabel, BeginLabel, 0, 0};
- CallSites.push_back(Site);
- PreviousIsInvoke = false;
- }
-
- LastLabel = LandingPad->EndLabels[P.RangeIndex];
- assert(BeginLabel && LastLabel && "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 (PreviousIsInvoke) {
- CallSiteEntry &Prev = CallSites.back();
- 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);
- 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 (SawPotentiallyThrowing) {
- CallSiteEntry Site = {LastLabel, 0, 0, 0};
- CallSites.push_back(Site);
- }
-
- // Final tallies.
-
- // Call sites.
- const unsigned SiteStartSize = sizeof(int32_t); // DW_EH_PE_udata4
- const unsigned SiteLengthSize = sizeof(int32_t); // DW_EH_PE_udata4
- const unsigned LandingPadSize = sizeof(int32_t); // DW_EH_PE_udata4
- unsigned SizeSites = CallSites.size() * (SiteStartSize +
- SiteLengthSize +
- LandingPadSize);
- for (unsigned i = 0, e = CallSites.size(); i < e; ++i)
- SizeSites += TargetAsmInfo::getULEB128Size(CallSites[i].Action);
-
- // Type infos.
- const unsigned TypeInfoSize = TD->getPointerSize(); // DW_EH_PE_absptr
- unsigned SizeTypes = TypeInfos.size() * TypeInfoSize;
-
- unsigned TypeOffset = sizeof(int8_t) + // Call site format
- TargetAsmInfo::getULEB128Size(SizeSites) + // Call-site table length
- SizeSites + SizeActions + SizeTypes;
-
- unsigned TotalSize = sizeof(int8_t) + // LPStart format
- sizeof(int8_t) + // TType format
- TargetAsmInfo::getULEB128Size(TypeOffset) + // TType base offset
- TypeOffset;
-
- unsigned SizeAlign = (4 - TotalSize) & 3;
-
- // Begin the exception table.
- Asm->SwitchToDataSection(TAI->getDwarfExceptionSection());
- Asm->EmitAlignment(2, 0, 0, false);
- O << "GCC_except_table" << SubprogramCount << ":\n";
- for (unsigned i = 0; i != SizeAlign; ++i) {
- Asm->EmitInt8(0);
- Asm->EOL("Padding");
- }
- EmitLabel("exception", SubprogramCount);
-
- // Emit the header.
- Asm->EmitInt8(DW_EH_PE_omit);
- Asm->EOL("LPStart format (DW_EH_PE_omit)");
- Asm->EmitInt8(DW_EH_PE_absptr);
- Asm->EOL("TType format (DW_EH_PE_absptr)");
- Asm->EmitULEB128Bytes(TypeOffset);
- Asm->EOL("TType base offset");
- Asm->EmitInt8(DW_EH_PE_udata4);
- Asm->EOL("Call site format (DW_EH_PE_udata4)");
- Asm->EmitULEB128Bytes(SizeSites);
- Asm->EOL("Call-site table length");
-
- // Emit the landing pad site information.
- for (unsigned i = 0; i < CallSites.size(); ++i) {
- CallSiteEntry &S = CallSites[i];
- const char *BeginTag;
- unsigned BeginNumber;
-
- if (!S.BeginLabel) {
- BeginTag = "eh_func_begin";
- BeginNumber = SubprogramCount;
- } else {
- BeginTag = "label";
- BeginNumber = S.BeginLabel;
- }
-
- EmitSectionOffset(BeginTag, "eh_func_begin", BeginNumber, SubprogramCount,
- true, true);
- Asm->EOL("Region start");
-
- if (!S.EndLabel) {
- EmitDifference("eh_func_end", SubprogramCount, BeginTag, BeginNumber,
- true);
- } else {
- EmitDifference("label", S.EndLabel, BeginTag, BeginNumber, true);
- }
- Asm->EOL("Region length");
-
- if (!S.PadLabel)
- Asm->EmitInt32(0);
- else
- EmitSectionOffset("label", "eh_func_begin", S.PadLabel, SubprogramCount,
- true, true);
- Asm->EOL("Landing pad");
-
- Asm->EmitULEB128Bytes(S.Action);
- Asm->EOL("Action");
- }
-
- // Emit the actions.
- for (unsigned I = 0, N = Actions.size(); I != N; ++I) {
- ActionEntry &Action = Actions[I];
-
- Asm->EmitSLEB128Bytes(Action.ValueForTypeID);
- Asm->EOL("TypeInfo index");
- Asm->EmitSLEB128Bytes(Action.NextAction);
- Asm->EOL("Next action");
- }
-
- // Emit the type ids.
- for (unsigned M = TypeInfos.size(); M; --M) {
- GlobalVariable *GV = TypeInfos[M - 1];
-
- PrintRelDirective();
-
- if (GV) {
- std::string GLN;
- O << Asm->getGlobalLinkName(GV, GLN);
- } else {
- O << "0";
- }
-
- Asm->EOL("TypeInfo");
- }
-
- // Emit the filter typeids.
- for (unsigned j = 0, M = FilterIds.size(); j < M; ++j) {
- unsigned TypeID = FilterIds[j];
- Asm->EmitULEB128Bytes(TypeID);
- Asm->EOL("Filter TypeInfo index");
- }
-
- Asm->EmitAlignment(2, 0, 0, false);
- }
-
-public:
- //===--------------------------------------------------------------------===//
- // Main entry points.
- //
- DwarfException(raw_ostream &OS, AsmPrinter *A, const TargetAsmInfo *T)
- : Dwarf(OS, A, T, "eh"), shouldEmitTable(false), shouldEmitMoves(false),
- shouldEmitTableModule(false), shouldEmitMovesModule(false),
- ExceptionTimer(0) {
- if (TimePassesIsEnabled)
- ExceptionTimer = new Timer("Dwarf Exception Writer",
- getDwarfTimerGroup());
- }
-
- virtual ~DwarfException() {
- delete ExceptionTimer;
- }
-
- /// SetModuleInfo - Set machine module information when it's known that pass
- /// manager has created it. Set by the target AsmPrinter.
- void SetModuleInfo(MachineModuleInfo *mmi) {
- MMI = mmi;
- }
-
- /// BeginModule - Emit all exception information that should come prior to the
- /// content.
- void BeginModule(Module *M) {
- this->M = M;
- }
-
- /// EndModule - Emit all exception information that should come after the
- /// content.
- void EndModule() {
- if (TimePassesIsEnabled)
- ExceptionTimer->startTimer();
-
- if (shouldEmitMovesModule || shouldEmitTableModule) {
- const std::vector<Function *> Personalities = MMI->getPersonalities();
- for (unsigned i = 0; i < Personalities.size(); ++i)
- EmitCommonEHFrame(Personalities[i], i);
-
- for (std::vector<FunctionEHFrameInfo>::iterator I = EHFrames.begin(),
- E = EHFrames.end(); I != E; ++I)
- EmitEHFrame(*I);
- }
-
- if (TimePassesIsEnabled)
- ExceptionTimer->stopTimer();
- }
-
- /// BeginFunction - Gather pre-function exception information. Assumes being
- /// emitted immediately after the function entry point.
- void BeginFunction(MachineFunction *MF) {
- if (TimePassesIsEnabled)
- ExceptionTimer->startTimer();
-
- this->MF = MF;
- shouldEmitTable = shouldEmitMoves = false;
-
- if (MMI && TAI->doesSupportExceptionHandling()) {
- // Map all labels and get rid of any dead landing pads.
- MMI->TidyLandingPads();
-
- // If any landing pads survive, we need an EH table.
- if (MMI->getLandingPads().size())
- shouldEmitTable = true;
-
- // See if we need frame move info.
- if (!MF->getFunction()->doesNotThrow() || UnwindTablesMandatory)
- shouldEmitMoves = true;
-
- if (shouldEmitMoves || shouldEmitTable)
- // Assumes in correct section after the entry point.
- EmitLabel("eh_func_begin", ++SubprogramCount);
- }
-
- shouldEmitTableModule |= shouldEmitTable;
- shouldEmitMovesModule |= shouldEmitMoves;
-
- if (TimePassesIsEnabled)
- ExceptionTimer->stopTimer();
- }
-
- /// EndFunction - Gather and emit post-function exception information.
- ///
- void EndFunction() {
- if (TimePassesIsEnabled)
- ExceptionTimer->startTimer();
-
- if (shouldEmitMoves || shouldEmitTable) {
- EmitLabel("eh_func_end", SubprogramCount);
- EmitExceptionTable();
-
- // Save EH frame information
- std::string Name;
- EHFrames.push_back(
- FunctionEHFrameInfo(getAsm()->getCurrentFunctionEHName(MF, Name),
- SubprogramCount,
- MMI->getPersonalityIndex(),
- MF->getFrameInfo()->hasCalls(),
- !MMI->getLandingPads().empty(),
- MMI->getFrameMoves(),
- MF->getFunction()));
- }
-
- if (TimePassesIsEnabled)
- ExceptionTimer->stopTimer();
- }
-};
-
} // End of namespace llvm
//===----------------------------------------------------------------------===//
projects / oota-llvm.git / commitdiff