1 //===-- CodeGen/AsmPrinter/DwarfException.cpp - Dwarf Exception Impl ------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file contains support for writing dwarf exception info into asm files.
12 //===----------------------------------------------------------------------===//
14 #include "DwarfException.h"
15 #include "llvm/Module.h"
16 #include "llvm/CodeGen/MachineModuleInfo.h"
17 #include "llvm/CodeGen/MachineFrameInfo.h"
18 #include "llvm/CodeGen/MachineLocation.h"
19 #include "llvm/Support/Dwarf.h"
20 #include "llvm/Support/Timer.h"
21 #include "llvm/Support/raw_ostream.h"
22 #include "llvm/Target/TargetAsmInfo.h"
23 #include "llvm/Target/TargetRegisterInfo.h"
24 #include "llvm/Target/TargetData.h"
25 #include "llvm/Target/TargetFrameInfo.h"
26 #include "llvm/Target/TargetOptions.h"
27 #include "llvm/ADT/StringExtras.h"
30 static TimerGroup &getDwarfTimerGroup() {
31 static TimerGroup DwarfTimerGroup("Dwarf Exception");
32 return DwarfTimerGroup;
35 DwarfException::DwarfException(raw_ostream &OS, AsmPrinter *A,
36 const TargetAsmInfo *T)
37 : Dwarf(OS, A, T, "eh"), shouldEmitTable(false), shouldEmitMoves(false),
38 shouldEmitTableModule(false), shouldEmitMovesModule(false),
40 if (TimePassesIsEnabled)
41 ExceptionTimer = new Timer("Dwarf Exception Writer",
42 getDwarfTimerGroup());
45 DwarfException::~DwarfException() {
46 delete ExceptionTimer;
49 void DwarfException::EmitCommonEHFrame(const Function *Personality,
51 // Size and sign of stack growth.
53 Asm->TM.getFrameInfo()->getStackGrowthDirection() ==
54 TargetFrameInfo::StackGrowsUp ?
55 TD->getPointerSize() : -TD->getPointerSize();
57 // Begin eh frame section.
58 Asm->SwitchToTextSection(TAI->getDwarfEHFrameSection());
60 if (TAI->is_EHSymbolPrivate())
61 O << TAI->getPrivateGlobalPrefix();
63 O << "EH_frame" << Index << ":\n";
64 EmitLabel("section_eh_frame", Index);
66 // Define base labels.
67 EmitLabel("eh_frame_common", Index);
69 // Define the eh frame length.
70 EmitDifference("eh_frame_common_end", Index,
71 "eh_frame_common_begin", Index, true);
72 Asm->EOL("Length of Common Information Entry");
75 EmitLabel("eh_frame_common_begin", Index);
76 Asm->EmitInt32((int)0);
77 Asm->EOL("CIE Identifier Tag");
78 Asm->EmitInt8(dwarf::DW_CIE_VERSION);
79 Asm->EOL("CIE Version");
81 // The personality presence indicates that language specific information will
82 // show up in the eh frame.
83 Asm->EmitString(Personality ? "zPLR" : "zR");
84 Asm->EOL("CIE Augmentation");
87 Asm->EmitULEB128Bytes(1);
88 Asm->EOL("CIE Code Alignment Factor");
89 Asm->EmitSLEB128Bytes(stackGrowth);
90 Asm->EOL("CIE Data Alignment Factor");
91 Asm->EmitInt8(RI->getDwarfRegNum(RI->getRARegister(), true));
92 Asm->EOL("CIE Return Address Column");
94 // If there is a personality, we need to indicate the functions location.
96 Asm->EmitULEB128Bytes(7);
97 Asm->EOL("Augmentation Size");
99 if (TAI->getNeedsIndirectEncoding()) {
100 Asm->EmitInt8(dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4 |
101 dwarf::DW_EH_PE_indirect);
102 Asm->EOL("Personality (pcrel sdata4 indirect)");
104 Asm->EmitInt8(dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4);
105 Asm->EOL("Personality (pcrel sdata4)");
108 PrintRelDirective(true);
109 O << TAI->getPersonalityPrefix();
110 Asm->EmitExternalGlobal((const GlobalVariable *)(Personality));
111 O << TAI->getPersonalitySuffix();
112 if (strcmp(TAI->getPersonalitySuffix(), "+4@GOTPCREL"))
113 O << "-" << TAI->getPCSymbol();
114 Asm->EOL("Personality");
116 Asm->EmitInt8(dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4);
117 Asm->EOL("LSDA Encoding (pcrel sdata4)");
119 Asm->EmitInt8(dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4);
120 Asm->EOL("FDE Encoding (pcrel sdata4)");
122 Asm->EmitULEB128Bytes(1);
123 Asm->EOL("Augmentation Size");
125 Asm->EmitInt8(dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4);
126 Asm->EOL("FDE Encoding (pcrel sdata4)");
129 // Indicate locations of general callee saved registers in frame.
130 std::vector<MachineMove> Moves;
131 RI->getInitialFrameState(Moves);
132 EmitFrameMoves(NULL, 0, Moves, true);
134 // On Darwin the linker honors the alignment of eh_frame, which means it must
135 // be 8-byte on 64-bit targets to match what gcc does. Otherwise you get
136 // holes which confuse readers of eh_frame.
137 Asm->EmitAlignment(TD->getPointerSize() == sizeof(int32_t) ? 2 : 3,
139 EmitLabel("eh_frame_common_end", Index);
144 /// EmitEHFrame - Emit function exception frame information.
146 void DwarfException::EmitEHFrame(const FunctionEHFrameInfo &EHFrameInfo) {
147 assert(!EHFrameInfo.function->hasAvailableExternallyLinkage() &&
148 "Should not emit 'available externally' functions at all");
150 Function::LinkageTypes linkage = EHFrameInfo.function->getLinkage();
151 Asm->SwitchToTextSection(TAI->getDwarfEHFrameSection());
153 // Externally visible entry into the functions eh frame info. If the
154 // corresponding function is static, this should not be externally visible.
155 if (linkage != Function::InternalLinkage &&
156 linkage != Function::PrivateLinkage) {
157 if (const char *GlobalEHDirective = TAI->getGlobalEHDirective())
158 O << GlobalEHDirective << EHFrameInfo.FnName << "\n";
161 // If corresponding function is weak definition, this should be too.
162 if ((linkage == Function::WeakAnyLinkage ||
163 linkage == Function::WeakODRLinkage ||
164 linkage == Function::LinkOnceAnyLinkage ||
165 linkage == Function::LinkOnceODRLinkage) &&
166 TAI->getWeakDefDirective())
167 O << TAI->getWeakDefDirective() << EHFrameInfo.FnName << "\n";
169 // If there are no calls then you can't unwind. This may mean we can omit the
170 // EH Frame, but some environments do not handle weak absolute symbols. If
171 // UnwindTablesMandatory is set we cannot do this optimization; the unwind
172 // info is to be available for non-EH uses.
173 if (!EHFrameInfo.hasCalls &&
174 !UnwindTablesMandatory &&
175 ((linkage != Function::WeakAnyLinkage &&
176 linkage != Function::WeakODRLinkage &&
177 linkage != Function::LinkOnceAnyLinkage &&
178 linkage != Function::LinkOnceODRLinkage) ||
179 !TAI->getWeakDefDirective() ||
180 TAI->getSupportsWeakOmittedEHFrame())) {
181 O << EHFrameInfo.FnName << " = 0\n";
182 // This name has no connection to the function, so it might get
183 // dead-stripped when the function is not, erroneously. Prohibit
184 // dead-stripping unconditionally.
185 if (const char *UsedDirective = TAI->getUsedDirective())
186 O << UsedDirective << EHFrameInfo.FnName << "\n\n";
188 O << EHFrameInfo.FnName << ":\n";
191 EmitDifference("eh_frame_end", EHFrameInfo.Number,
192 "eh_frame_begin", EHFrameInfo.Number, true);
193 Asm->EOL("Length of Frame Information Entry");
195 EmitLabel("eh_frame_begin", EHFrameInfo.Number);
197 EmitSectionOffset("eh_frame_begin", "eh_frame_common",
198 EHFrameInfo.Number, EHFrameInfo.PersonalityIndex,
201 Asm->EOL("FDE CIE offset");
203 EmitReference("eh_func_begin", EHFrameInfo.Number, true, true);
204 Asm->EOL("FDE initial location");
205 EmitDifference("eh_func_end", EHFrameInfo.Number,
206 "eh_func_begin", EHFrameInfo.Number, true);
207 Asm->EOL("FDE address range");
209 // If there is a personality and landing pads then point to the language
210 // specific data area in the exception table.
211 if (EHFrameInfo.PersonalityIndex) {
212 Asm->EmitULEB128Bytes(4);
213 Asm->EOL("Augmentation size");
215 if (EHFrameInfo.hasLandingPads)
216 EmitReference("exception", EHFrameInfo.Number, true, true);
218 Asm->EmitInt32((int)0);
219 Asm->EOL("Language Specific Data Area");
221 Asm->EmitULEB128Bytes(0);
222 Asm->EOL("Augmentation size");
225 // Indicate locations of function specific callee saved registers in frame.
226 EmitFrameMoves("eh_func_begin", EHFrameInfo.Number, EHFrameInfo.Moves,
229 // On Darwin the linker honors the alignment of eh_frame, which means it
230 // must be 8-byte on 64-bit targets to match what gcc does. Otherwise you
231 // get holes which confuse readers of eh_frame.
232 Asm->EmitAlignment(TD->getPointerSize() == sizeof(int32_t) ? 2 : 3,
234 EmitLabel("eh_frame_end", EHFrameInfo.Number);
236 // If the function is marked used, this table should be also. We cannot
237 // make the mark unconditional in this case, since retaining the table also
238 // retains the function in this case, and there is code around that depends
239 // on unused functions (calling undefined externals) being dead-stripped to
240 // link correctly. Yes, there really is.
241 if (MMI->getUsedFunctions().count(EHFrameInfo.function))
242 if (const char *UsedDirective = TAI->getUsedDirective())
243 O << UsedDirective << EHFrameInfo.FnName << "\n\n";
247 /// EmitExceptionTable - Emit landing pads and actions.
249 /// The general organization of the table is complex, but the basic concepts are
250 /// easy. First there is a header which describes the location and organization
251 /// of the three components that follow.
253 /// 1. The landing pad site information describes the range of code covered by
254 /// the try. In our case it's an accumulation of the ranges covered by the
255 /// invokes in the try. There is also a reference to the landing pad that
256 /// handles the exception once processed. Finally an index into the actions
258 /// 2. The action table, in our case, is composed of pairs of type ids and next
259 /// action offset. Starting with the action index from the landing pad
260 /// site, each type Id is checked for a match to the current exception. If
261 /// it matches then the exception and type id are passed on to the landing
262 /// pad. Otherwise the next action is looked up. This chain is terminated
263 /// with a next action of zero. If no type id is found the the frame is
264 /// unwound and handling continues.
265 /// 3. Type id table contains references to all the C++ typeinfo for all
266 /// catches in the function. This tables is reversed indexed base 1.
268 /// SharedTypeIds - How many leading type ids two landing pads have in common.
269 unsigned DwarfException::SharedTypeIds(const LandingPadInfo *L,
270 const LandingPadInfo *R) {
271 const std::vector<int> &LIds = L->TypeIds, &RIds = R->TypeIds;
272 unsigned LSize = LIds.size(), RSize = RIds.size();
273 unsigned MinSize = LSize < RSize ? LSize : RSize;
276 for (; Count != MinSize; ++Count)
277 if (LIds[Count] != RIds[Count])
283 /// PadLT - Order landing pads lexicographically by type id.
284 bool DwarfException::PadLT(const LandingPadInfo *L, const LandingPadInfo *R) {
285 const std::vector<int> &LIds = L->TypeIds, &RIds = R->TypeIds;
286 unsigned LSize = LIds.size(), RSize = RIds.size();
287 unsigned MinSize = LSize < RSize ? LSize : RSize;
289 for (unsigned i = 0; i != MinSize; ++i)
290 if (LIds[i] != RIds[i])
291 return LIds[i] < RIds[i];
293 return LSize < RSize;
296 void DwarfException::EmitExceptionTable() {
297 const std::vector<GlobalVariable *> &TypeInfos = MMI->getTypeInfos();
298 const std::vector<unsigned> &FilterIds = MMI->getFilterIds();
299 const std::vector<LandingPadInfo> &PadInfos = MMI->getLandingPads();
300 if (PadInfos.empty()) return;
302 // Sort the landing pads in order of their type ids. This is used to fold
303 // duplicate actions.
304 SmallVector<const LandingPadInfo *, 64> LandingPads;
305 LandingPads.reserve(PadInfos.size());
306 for (unsigned i = 0, N = PadInfos.size(); i != N; ++i)
307 LandingPads.push_back(&PadInfos[i]);
308 std::sort(LandingPads.begin(), LandingPads.end(), PadLT);
310 // Negative type ids index into FilterIds, positive type ids index into
311 // TypeInfos. The value written for a positive type id is just the type id
312 // itself. For a negative type id, however, the value written is the
313 // (negative) byte offset of the corresponding FilterIds entry. The byte
314 // offset is usually equal to the type id, because the FilterIds entries are
315 // written using a variable width encoding which outputs one byte per entry as
316 // long as the value written is not too large, but can differ. This kind of
317 // complication does not occur for positive type ids because type infos are
318 // output using a fixed width encoding. FilterOffsets[i] holds the byte
319 // offset corresponding to FilterIds[i].
320 SmallVector<int, 16> FilterOffsets;
321 FilterOffsets.reserve(FilterIds.size());
323 for(std::vector<unsigned>::const_iterator I = FilterIds.begin(),
324 E = FilterIds.end(); I != E; ++I) {
325 FilterOffsets.push_back(Offset);
326 Offset -= TargetAsmInfo::getULEB128Size(*I);
329 // Compute the actions table and gather the first action index for each
331 SmallVector<ActionEntry, 32> Actions;
332 SmallVector<unsigned, 64> FirstActions;
333 FirstActions.reserve(LandingPads.size());
336 unsigned SizeActions = 0;
337 for (unsigned i = 0, N = LandingPads.size(); i != N; ++i) {
338 const LandingPadInfo *LP = LandingPads[i];
339 const std::vector<int> &TypeIds = LP->TypeIds;
340 const unsigned NumShared = i ? SharedTypeIds(LP, LandingPads[i-1]) : 0;
341 unsigned SizeSiteActions = 0;
343 if (NumShared < TypeIds.size()) {
344 unsigned SizeAction = 0;
345 ActionEntry *PrevAction = 0;
348 const unsigned SizePrevIds = LandingPads[i-1]->TypeIds.size();
349 assert(Actions.size());
350 PrevAction = &Actions.back();
351 SizeAction = TargetAsmInfo::getSLEB128Size(PrevAction->NextAction) +
352 TargetAsmInfo::getSLEB128Size(PrevAction->ValueForTypeID);
354 for (unsigned j = NumShared; j != SizePrevIds; ++j) {
356 TargetAsmInfo::getSLEB128Size(PrevAction->ValueForTypeID);
357 SizeAction += -PrevAction->NextAction;
358 PrevAction = PrevAction->Previous;
362 // Compute the actions.
363 for (unsigned I = NumShared, M = TypeIds.size(); I != M; ++I) {
364 int TypeID = TypeIds[I];
365 assert(-1-TypeID < (int)FilterOffsets.size() && "Unknown filter id!");
366 int ValueForTypeID = TypeID < 0 ? FilterOffsets[-1 - TypeID] : TypeID;
367 unsigned SizeTypeID = TargetAsmInfo::getSLEB128Size(ValueForTypeID);
369 int NextAction = SizeAction ? -(SizeAction + SizeTypeID) : 0;
370 SizeAction = SizeTypeID + TargetAsmInfo::getSLEB128Size(NextAction);
371 SizeSiteActions += SizeAction;
373 ActionEntry Action = {ValueForTypeID, NextAction, PrevAction};
374 Actions.push_back(Action);
376 PrevAction = &Actions.back();
379 // Record the first action of the landing pad site.
380 FirstAction = SizeActions + SizeSiteActions - SizeAction + 1;
381 } // else identical - re-use previous FirstAction
383 FirstActions.push_back(FirstAction);
385 // Compute this sites contribution to size.
386 SizeActions += SizeSiteActions;
389 // Compute the call-site table. The entry for an invoke has a try-range
390 // containing the call, a non-zero landing pad and an appropriate action. The
391 // entry for an ordinary call has a try-range containing the call and zero for
392 // the landing pad and the action. Calls marked 'nounwind' have no entry and
393 // must not be contained in the try-range of any entry - they form gaps in the
394 // table. Entries must be ordered by try-range address.
395 SmallVector<CallSiteEntry, 64> CallSites;
399 // Invokes and nounwind calls have entries in PadMap (due to being bracketed
400 // by try-range labels when lowered). Ordinary calls do not, so appropriate
401 // try-ranges for them need be deduced.
402 for (unsigned i = 0, N = LandingPads.size(); i != N; ++i) {
403 const LandingPadInfo *LandingPad = LandingPads[i];
404 for (unsigned j = 0, E = LandingPad->BeginLabels.size(); j != E; ++j) {
405 unsigned BeginLabel = LandingPad->BeginLabels[j];
406 assert(!PadMap.count(BeginLabel) && "Duplicate landing pad labels!");
407 PadRange P = { i, j };
408 PadMap[BeginLabel] = P;
412 // The end label of the previous invoke or nounwind try-range.
413 unsigned LastLabel = 0;
415 // Whether there is a potentially throwing instruction (currently this means
416 // an ordinary call) between the end of the previous try-range and now.
417 bool SawPotentiallyThrowing = false;
419 // Whether the last callsite entry was for an invoke.
420 bool PreviousIsInvoke = false;
422 // Visit all instructions in order of address.
423 for (MachineFunction::const_iterator I = MF->begin(), E = MF->end();
425 for (MachineBasicBlock::const_iterator MI = I->begin(), E = I->end();
427 if (!MI->isLabel()) {
428 SawPotentiallyThrowing |= MI->getDesc().isCall();
432 unsigned BeginLabel = MI->getOperand(0).getImm();
433 assert(BeginLabel && "Invalid label!");
435 // End of the previous try-range?
436 if (BeginLabel == LastLabel)
437 SawPotentiallyThrowing = false;
439 // Beginning of a new try-range?
440 RangeMapType::iterator L = PadMap.find(BeginLabel);
441 if (L == PadMap.end())
442 // Nope, it was just some random label.
445 PadRange P = L->second;
446 const LandingPadInfo *LandingPad = LandingPads[P.PadIndex];
448 assert(BeginLabel == LandingPad->BeginLabels[P.RangeIndex] &&
449 "Inconsistent landing pad map!");
451 // If some instruction between the previous try-range and this one may
452 // throw, create a call-site entry with no landing pad for the region
453 // between the try-ranges.
454 if (SawPotentiallyThrowing) {
455 CallSiteEntry Site = {LastLabel, BeginLabel, 0, 0};
456 CallSites.push_back(Site);
457 PreviousIsInvoke = false;
460 LastLabel = LandingPad->EndLabels[P.RangeIndex];
461 assert(BeginLabel && LastLabel && "Invalid landing pad!");
463 if (LandingPad->LandingPadLabel) {
464 // This try-range is for an invoke.
465 CallSiteEntry Site = {BeginLabel, LastLabel,
466 LandingPad->LandingPadLabel,
467 FirstActions[P.PadIndex]};
469 // Try to merge with the previous call-site.
470 if (PreviousIsInvoke) {
471 CallSiteEntry &Prev = CallSites.back();
472 if (Site.PadLabel == Prev.PadLabel && Site.Action == Prev.Action) {
473 // Extend the range of the previous entry.
474 Prev.EndLabel = Site.EndLabel;
479 // Otherwise, create a new call-site.
480 CallSites.push_back(Site);
481 PreviousIsInvoke = true;
484 PreviousIsInvoke = false;
489 // If some instruction between the previous try-range and the end of the
490 // function may throw, create a call-site entry with no landing pad for the
491 // region following the try-range.
492 if (SawPotentiallyThrowing) {
493 CallSiteEntry Site = {LastLabel, 0, 0, 0};
494 CallSites.push_back(Site);
500 const unsigned SiteStartSize = sizeof(int32_t); // DW_EH_PE_udata4
501 const unsigned SiteLengthSize = sizeof(int32_t); // DW_EH_PE_udata4
502 const unsigned LandingPadSize = sizeof(int32_t); // DW_EH_PE_udata4
503 unsigned SizeSites = CallSites.size() * (SiteStartSize +
506 for (unsigned i = 0, e = CallSites.size(); i < e; ++i)
507 SizeSites += TargetAsmInfo::getULEB128Size(CallSites[i].Action);
510 const unsigned TypeInfoSize = TD->getPointerSize(); // DW_EH_PE_absptr
511 unsigned SizeTypes = TypeInfos.size() * TypeInfoSize;
513 unsigned TypeOffset = sizeof(int8_t) + // Call site format
514 TargetAsmInfo::getULEB128Size(SizeSites) + // Call-site table length
515 SizeSites + SizeActions + SizeTypes;
517 unsigned TotalSize = sizeof(int8_t) + // LPStart format
518 sizeof(int8_t) + // TType format
519 TargetAsmInfo::getULEB128Size(TypeOffset) + // TType base offset
522 unsigned SizeAlign = (4 - TotalSize) & 3;
524 // Begin the exception table.
525 Asm->SwitchToDataSection(TAI->getDwarfExceptionSection());
526 Asm->EmitAlignment(2, 0, 0, false);
527 O << "GCC_except_table" << SubprogramCount << ":\n";
529 for (unsigned i = 0; i != SizeAlign; ++i) {
534 EmitLabel("exception", SubprogramCount);
537 Asm->EmitInt8(dwarf::DW_EH_PE_omit);
538 Asm->EOL("LPStart format (DW_EH_PE_omit)");
539 Asm->EmitInt8(dwarf::DW_EH_PE_absptr);
540 Asm->EOL("TType format (DW_EH_PE_absptr)");
541 Asm->EmitULEB128Bytes(TypeOffset);
542 Asm->EOL("TType base offset");
543 Asm->EmitInt8(dwarf::DW_EH_PE_udata4);
544 Asm->EOL("Call site format (DW_EH_PE_udata4)");
545 Asm->EmitULEB128Bytes(SizeSites);
546 Asm->EOL("Call-site table length");
548 // Emit the landing pad site information.
549 for (unsigned i = 0; i < CallSites.size(); ++i) {
550 CallSiteEntry &S = CallSites[i];
551 const char *BeginTag;
552 unsigned BeginNumber;
555 BeginTag = "eh_func_begin";
556 BeginNumber = SubprogramCount;
559 BeginNumber = S.BeginLabel;
562 EmitSectionOffset(BeginTag, "eh_func_begin", BeginNumber, SubprogramCount,
564 Asm->EOL("Region start");
567 EmitDifference("eh_func_end", SubprogramCount, BeginTag, BeginNumber,
570 EmitDifference("label", S.EndLabel, BeginTag, BeginNumber, true);
572 Asm->EOL("Region length");
577 EmitSectionOffset("label", "eh_func_begin", S.PadLabel, SubprogramCount,
580 Asm->EOL("Landing pad");
582 Asm->EmitULEB128Bytes(S.Action);
587 for (unsigned I = 0, N = Actions.size(); I != N; ++I) {
588 ActionEntry &Action = Actions[I];
590 Asm->EmitSLEB128Bytes(Action.ValueForTypeID);
591 Asm->EOL("TypeInfo index");
592 Asm->EmitSLEB128Bytes(Action.NextAction);
593 Asm->EOL("Next action");
596 // Emit the type ids.
597 for (unsigned M = TypeInfos.size(); M; --M) {
598 GlobalVariable *GV = TypeInfos[M - 1];
603 O << Asm->getGlobalLinkName(GV, GLN);
608 Asm->EOL("TypeInfo");
611 // Emit the filter typeids.
612 for (unsigned j = 0, M = FilterIds.size(); j < M; ++j) {
613 unsigned TypeID = FilterIds[j];
614 Asm->EmitULEB128Bytes(TypeID);
615 Asm->EOL("Filter TypeInfo index");
618 Asm->EmitAlignment(2, 0, 0, false);
621 /// EndModule - Emit all exception information that should come after the
623 void DwarfException::EndModule() {
624 if (TimePassesIsEnabled)
625 ExceptionTimer->startTimer();
627 if (shouldEmitMovesModule || shouldEmitTableModule) {
628 const std::vector<Function *> Personalities = MMI->getPersonalities();
629 for (unsigned i = 0; i < Personalities.size(); ++i)
630 EmitCommonEHFrame(Personalities[i], i);
632 for (std::vector<FunctionEHFrameInfo>::iterator I = EHFrames.begin(),
633 E = EHFrames.end(); I != E; ++I)
637 if (TimePassesIsEnabled)
638 ExceptionTimer->stopTimer();
641 /// BeginFunction - Gather pre-function exception information. Assumes being
642 /// emitted immediately after the function entry point.
643 void DwarfException::BeginFunction(MachineFunction *MF) {
644 if (TimePassesIsEnabled)
645 ExceptionTimer->startTimer();
648 shouldEmitTable = shouldEmitMoves = false;
650 if (MMI && TAI->doesSupportExceptionHandling()) {
651 // Map all labels and get rid of any dead landing pads.
652 MMI->TidyLandingPads();
654 // If any landing pads survive, we need an EH table.
655 if (MMI->getLandingPads().size())
656 shouldEmitTable = true;
658 // See if we need frame move info.
659 if (!MF->getFunction()->doesNotThrow() || UnwindTablesMandatory)
660 shouldEmitMoves = true;
662 if (shouldEmitMoves || shouldEmitTable)
663 // Assumes in correct section after the entry point.
664 EmitLabel("eh_func_begin", ++SubprogramCount);
667 shouldEmitTableModule |= shouldEmitTable;
668 shouldEmitMovesModule |= shouldEmitMoves;
670 if (TimePassesIsEnabled)
671 ExceptionTimer->stopTimer();
674 /// EndFunction - Gather and emit post-function exception information.
676 void DwarfException::EndFunction() {
677 if (TimePassesIsEnabled)
678 ExceptionTimer->startTimer();
680 if (shouldEmitMoves || shouldEmitTable) {
681 EmitLabel("eh_func_end", SubprogramCount);
682 EmitExceptionTable();
684 // Save EH frame information
686 FunctionEHFrameInfo(getAsm()->getCurrentFunctionEHName(MF),
688 MMI->getPersonalityIndex(),
689 MF->getFrameInfo()->hasCalls(),
690 !MMI->getLandingPads().empty(),
691 MMI->getFrameMoves(),
695 if (TimePassesIsEnabled)
696 ExceptionTimer->stopTimer();