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 const Function *TheFunc = EHFrameInfo.function;
152 Asm->SwitchToTextSection(TAI->getDwarfEHFrameSection());
154 // Externally visible entry into the functions eh frame info. If the
155 // corresponding function is static, this should not be externally visible.
156 if (!TheFunc->hasLocalLinkage())
157 if (const char *GlobalEHDirective = TAI->getGlobalEHDirective())
158 O << GlobalEHDirective << EHFrameInfo.FnName << "\n";
160 // If corresponding function is weak definition, this should be too.
161 if (TheFunc->isWeakForLinker() && TAI->getWeakDefDirective())
162 O << TAI->getWeakDefDirective() << EHFrameInfo.FnName << "\n";
164 // If there are no calls then you can't unwind. This may mean we can omit the
165 // EH Frame, but some environments do not handle weak absolute symbols. If
166 // UnwindTablesMandatory is set we cannot do this optimization; the unwind
167 // info is to be available for non-EH uses.
168 if (!EHFrameInfo.hasCalls && !UnwindTablesMandatory &&
169 (!TheFunc->isWeakForLinker() ||
170 !TAI->getWeakDefDirective() ||
171 TAI->getSupportsWeakOmittedEHFrame())) {
172 O << EHFrameInfo.FnName << " = 0\n";
173 // This name has no connection to the function, so it might get
174 // dead-stripped when the function is not, erroneously. Prohibit
175 // dead-stripping unconditionally.
176 if (const char *UsedDirective = TAI->getUsedDirective())
177 O << UsedDirective << EHFrameInfo.FnName << "\n\n";
179 O << EHFrameInfo.FnName << ":\n";
182 EmitDifference("eh_frame_end", EHFrameInfo.Number,
183 "eh_frame_begin", EHFrameInfo.Number, true);
184 Asm->EOL("Length of Frame Information Entry");
186 EmitLabel("eh_frame_begin", EHFrameInfo.Number);
188 EmitSectionOffset("eh_frame_begin", "eh_frame_common",
189 EHFrameInfo.Number, EHFrameInfo.PersonalityIndex,
192 Asm->EOL("FDE CIE offset");
194 EmitReference("eh_func_begin", EHFrameInfo.Number, true, true);
195 Asm->EOL("FDE initial location");
196 EmitDifference("eh_func_end", EHFrameInfo.Number,
197 "eh_func_begin", EHFrameInfo.Number, true);
198 Asm->EOL("FDE address range");
200 // If there is a personality and landing pads then point to the language
201 // specific data area in the exception table.
202 if (EHFrameInfo.PersonalityIndex) {
203 Asm->EmitULEB128Bytes(4);
204 Asm->EOL("Augmentation size");
206 if (EHFrameInfo.hasLandingPads)
207 EmitReference("exception", EHFrameInfo.Number, true, true);
209 Asm->EmitInt32((int)0);
210 Asm->EOL("Language Specific Data Area");
212 Asm->EmitULEB128Bytes(0);
213 Asm->EOL("Augmentation size");
216 // Indicate locations of function specific callee saved registers in frame.
217 EmitFrameMoves("eh_func_begin", EHFrameInfo.Number, EHFrameInfo.Moves,
220 // On Darwin the linker honors the alignment of eh_frame, which means it
221 // must be 8-byte on 64-bit targets to match what gcc does. Otherwise you
222 // get holes which confuse readers of eh_frame.
223 Asm->EmitAlignment(TD->getPointerSize() == sizeof(int32_t) ? 2 : 3,
225 EmitLabel("eh_frame_end", EHFrameInfo.Number);
227 // If the function is marked used, this table should be also. We cannot
228 // make the mark unconditional in this case, since retaining the table also
229 // retains the function in this case, and there is code around that depends
230 // on unused functions (calling undefined externals) being dead-stripped to
231 // link correctly. Yes, there really is.
232 if (MMI->isUsedFunction(EHFrameInfo.function))
233 if (const char *UsedDirective = TAI->getUsedDirective())
234 O << UsedDirective << EHFrameInfo.FnName << "\n\n";
238 /// SharedTypeIds - How many leading type ids two landing pads have in common.
239 unsigned DwarfException::SharedTypeIds(const LandingPadInfo *L,
240 const LandingPadInfo *R) {
241 const std::vector<int> &LIds = L->TypeIds, &RIds = R->TypeIds;
242 unsigned LSize = LIds.size(), RSize = RIds.size();
243 unsigned MinSize = LSize < RSize ? LSize : RSize;
246 for (; Count != MinSize; ++Count)
247 if (LIds[Count] != RIds[Count])
253 /// PadLT - Order landing pads lexicographically by type id.
254 bool DwarfException::PadLT(const LandingPadInfo *L, const LandingPadInfo *R) {
255 const std::vector<int> &LIds = L->TypeIds, &RIds = R->TypeIds;
256 unsigned LSize = LIds.size(), RSize = RIds.size();
257 unsigned MinSize = LSize < RSize ? LSize : RSize;
259 for (unsigned i = 0; i != MinSize; ++i)
260 if (LIds[i] != RIds[i])
261 return LIds[i] < RIds[i];
263 return LSize < RSize;
266 /// ComputeActionsTable - Compute the actions table and gather the first action
267 /// index for each landing pad site.
268 unsigned DwarfException::
269 ComputeActionsTable(const SmallVectorImpl<const LandingPadInfo*> &LandingPads,
270 SmallVectorImpl<ActionEntry> &Actions,
271 SmallVectorImpl<unsigned> &FirstActions) {
272 // Negative type IDs index into FilterIds. Positive type IDs index into
273 // TypeInfos. The value written for a positive type ID is just the type ID
274 // itself. For a negative type ID, however, the value written is the
275 // (negative) byte offset of the corresponding FilterIds entry. The byte
276 // offset is usually equal to the type ID (because the FilterIds entries are
277 // written using a variable width encoding, which outputs one byte per entry
278 // as long as the value written is not too large) but can differ. This kind
279 // of complication does not occur for positive type IDs because type infos are
280 // output using a fixed width encoding. FilterOffsets[i] holds the byte
281 // offset corresponding to FilterIds[i].
283 const std::vector<unsigned> &FilterIds = MMI->getFilterIds();
284 SmallVector<int, 16> FilterOffsets;
285 FilterOffsets.reserve(FilterIds.size());
288 for (std::vector<unsigned>::const_iterator
289 I = FilterIds.begin(), E = FilterIds.end(); I != E; ++I) {
290 FilterOffsets.push_back(Offset);
291 Offset -= TargetAsmInfo::getULEB128Size(*I);
294 FirstActions.reserve(LandingPads.size());
297 unsigned SizeActions = 0;
298 const LandingPadInfo *PrevLPI = 0;
300 for (SmallVectorImpl<const LandingPadInfo *>::const_iterator
301 I = LandingPads.begin(), E = LandingPads.end(); I != E; ++I) {
302 const LandingPadInfo *LPI = *I;
303 const std::vector<int> &TypeIds = LPI->TypeIds;
304 const unsigned NumShared = PrevLPI ? SharedTypeIds(LPI, PrevLPI) : 0;
305 unsigned SizeSiteActions = 0;
307 if (NumShared < TypeIds.size()) {
308 unsigned SizeAction = 0;
309 ActionEntry *PrevAction = 0;
312 const unsigned SizePrevIds = PrevLPI->TypeIds.size();
313 assert(Actions.size());
314 PrevAction = &Actions.back();
315 SizeAction = TargetAsmInfo::getSLEB128Size(PrevAction->NextAction) +
316 TargetAsmInfo::getSLEB128Size(PrevAction->ValueForTypeID);
318 for (unsigned j = NumShared; j != SizePrevIds; ++j) {
320 TargetAsmInfo::getSLEB128Size(PrevAction->ValueForTypeID);
321 SizeAction += -PrevAction->NextAction;
322 PrevAction = PrevAction->Previous;
326 // Compute the actions.
327 for (unsigned J = NumShared, M = TypeIds.size(); J != M; ++J) {
328 int TypeID = TypeIds[J];
329 assert(-1 - TypeID < (int)FilterOffsets.size() && "Unknown filter id!");
330 int ValueForTypeID = TypeID < 0 ? FilterOffsets[-1 - TypeID] : TypeID;
331 unsigned SizeTypeID = TargetAsmInfo::getSLEB128Size(ValueForTypeID);
333 int NextAction = SizeAction ? -(SizeAction + SizeTypeID) : 0;
334 SizeAction = SizeTypeID + TargetAsmInfo::getSLEB128Size(NextAction);
335 SizeSiteActions += SizeAction;
337 ActionEntry Action = {ValueForTypeID, NextAction, PrevAction};
338 Actions.push_back(Action);
339 PrevAction = &Actions.back();
342 // Record the first action of the landing pad site.
343 FirstAction = SizeActions + SizeSiteActions - SizeAction + 1;
344 } // else identical - re-use previous FirstAction
346 FirstActions.push_back(FirstAction);
348 // Compute this sites contribution to size.
349 SizeActions += SizeSiteActions;
357 /// ComputeCallSiteTable - Compute the call-site table. The entry for an invoke
358 /// has a try-range containing the call, a non-zero landing pad and an
359 /// appropriate action. The entry for an ordinary call has a try-range
360 /// containing the call and zero for the landing pad and the action. Calls
361 /// marked 'nounwind' have no entry and must not be contained in the try-range
362 /// of any entry - they form gaps in the table. Entries must be ordered by
363 /// try-range address.
364 void DwarfException::
365 ComputeCallSiteTable(SmallVectorImpl<CallSiteEntry> &CallSites,
366 const RangeMapType &PadMap,
367 const SmallVectorImpl<const LandingPadInfo *> &LandingPads,
368 const SmallVectorImpl<unsigned> &FirstActions) {
369 // The end label of the previous invoke or nounwind try-range.
370 unsigned LastLabel = 0;
372 // Whether there is a potentially throwing instruction (currently this means
373 // an ordinary call) between the end of the previous try-range and now.
374 bool SawPotentiallyThrowing = false;
376 // Whether the last CallSite entry was for an invoke.
377 bool PreviousIsInvoke = false;
379 // Visit all instructions in order of address.
380 for (MachineFunction::const_iterator I = MF->begin(), E = MF->end();
382 for (MachineBasicBlock::const_iterator MI = I->begin(), E = I->end();
384 if (!MI->isLabel()) {
385 SawPotentiallyThrowing |= MI->getDesc().isCall();
389 unsigned BeginLabel = MI->getOperand(0).getImm();
390 assert(BeginLabel && "Invalid label!");
392 // End of the previous try-range?
393 if (BeginLabel == LastLabel)
394 SawPotentiallyThrowing = false;
396 // Beginning of a new try-range?
397 RangeMapType::iterator L = PadMap.find(BeginLabel);
398 if (L == PadMap.end())
399 // Nope, it was just some random label.
402 PadRange P = L->second;
403 const LandingPadInfo *LandingPad = LandingPads[P.PadIndex];
404 assert(BeginLabel == LandingPad->BeginLabels[P.RangeIndex] &&
405 "Inconsistent landing pad map!");
407 // If some instruction between the previous try-range and this one may
408 // throw, create a call-site entry with no landing pad for the region
409 // between the try-ranges.
410 if (SawPotentiallyThrowing) {
411 CallSiteEntry Site = {LastLabel, BeginLabel, 0, 0};
412 CallSites.push_back(Site);
413 PreviousIsInvoke = false;
416 LastLabel = LandingPad->EndLabels[P.RangeIndex];
417 assert(BeginLabel && LastLabel && "Invalid landing pad!");
419 if (LandingPad->LandingPadLabel) {
420 // This try-range is for an invoke.
421 CallSiteEntry Site = {BeginLabel, LastLabel,
422 LandingPad->LandingPadLabel,
423 FirstActions[P.PadIndex]};
425 // Try to merge with the previous call-site.
426 if (PreviousIsInvoke) {
427 CallSiteEntry &Prev = CallSites.back();
428 if (Site.PadLabel == Prev.PadLabel && Site.Action == Prev.Action) {
429 // Extend the range of the previous entry.
430 Prev.EndLabel = Site.EndLabel;
435 // Otherwise, create a new call-site.
436 CallSites.push_back(Site);
437 PreviousIsInvoke = true;
440 PreviousIsInvoke = false;
445 // If some instruction between the previous try-range and the end of the
446 // function may throw, create a call-site entry with no landing pad for the
447 // region following the try-range.
448 if (SawPotentiallyThrowing) {
449 CallSiteEntry Site = {LastLabel, 0, 0, 0};
450 CallSites.push_back(Site);
454 /// EmitExceptionTable - Emit landing pads and actions.
456 /// The general organization of the table is complex, but the basic concepts are
457 /// easy. First there is a header which describes the location and organization
458 /// of the three components that follow.
460 /// 1. The landing pad site information describes the range of code covered by
461 /// the try. In our case it's an accumulation of the ranges covered by the
462 /// invokes in the try. There is also a reference to the landing pad that
463 /// handles the exception once processed. Finally an index into the actions
465 /// 2. The action table, in our case, is composed of pairs of type ids and next
466 /// action offset. Starting with the action index from the landing pad
467 /// site, each type Id is checked for a match to the current exception. If
468 /// it matches then the exception and type id are passed on to the landing
469 /// pad. Otherwise the next action is looked up. This chain is terminated
470 /// with a next action of zero. If no type id is found the the frame is
471 /// unwound and handling continues.
472 /// 3. Type id table contains references to all the C++ typeinfo for all
473 /// catches in the function. This tables is reversed indexed base 1.
474 void DwarfException::EmitExceptionTable() {
475 const std::vector<GlobalVariable *> &TypeInfos = MMI->getTypeInfos();
476 const std::vector<unsigned> &FilterIds = MMI->getFilterIds();
477 const std::vector<LandingPadInfo> &PadInfos = MMI->getLandingPads();
478 if (PadInfos.empty()) return;
480 // Sort the landing pads in order of their type ids. This is used to fold
481 // duplicate actions.
482 SmallVector<const LandingPadInfo *, 64> LandingPads;
483 LandingPads.reserve(PadInfos.size());
485 for (unsigned i = 0, N = PadInfos.size(); i != N; ++i)
486 LandingPads.push_back(&PadInfos[i]);
488 std::sort(LandingPads.begin(), LandingPads.end(), PadLT);
490 // Compute the actions table and gather the first action index for each
492 SmallVector<ActionEntry, 32> Actions;
493 SmallVector<unsigned, 64> FirstActions;
494 unsigned SizeActions = ComputeActionsTable(LandingPads, Actions, FirstActions);
496 // Invokes and nounwind calls have entries in PadMap (due to being bracketed
497 // by try-range labels when lowered). Ordinary calls do not, so appropriate
498 // try-ranges for them need be deduced.
500 for (unsigned i = 0, N = LandingPads.size(); i != N; ++i) {
501 const LandingPadInfo *LandingPad = LandingPads[i];
502 for (unsigned j = 0, E = LandingPad->BeginLabels.size(); j != E; ++j) {
503 unsigned BeginLabel = LandingPad->BeginLabels[j];
504 assert(!PadMap.count(BeginLabel) && "Duplicate landing pad labels!");
505 PadRange P = { i, j };
506 PadMap[BeginLabel] = P;
510 // Compute the call-site table.
511 SmallVector<CallSiteEntry, 64> CallSites;
512 ComputeCallSiteTable(CallSites, PadMap, LandingPads, FirstActions);
517 const unsigned SiteStartSize = sizeof(int32_t); // DW_EH_PE_udata4
518 const unsigned SiteLengthSize = sizeof(int32_t); // DW_EH_PE_udata4
519 const unsigned LandingPadSize = sizeof(int32_t); // DW_EH_PE_udata4
520 unsigned SizeSites = CallSites.size() * (SiteStartSize +
523 for (unsigned i = 0, e = CallSites.size(); i < e; ++i)
524 SizeSites += TargetAsmInfo::getULEB128Size(CallSites[i].Action);
527 const unsigned TypeInfoSize = TD->getPointerSize(); // DW_EH_PE_absptr
528 unsigned SizeTypes = TypeInfos.size() * TypeInfoSize;
530 unsigned TypeOffset = sizeof(int8_t) + // Call site format
531 TargetAsmInfo::getULEB128Size(SizeSites) + // Call-site table length
532 SizeSites + SizeActions + SizeTypes;
534 unsigned TotalSize = sizeof(int8_t) + // LPStart format
535 sizeof(int8_t) + // TType format
536 TargetAsmInfo::getULEB128Size(TypeOffset) + // TType base offset
539 unsigned SizeAlign = (4 - TotalSize) & 3;
541 // Begin the exception table.
542 //MCSection *LSDASection = TAI->getLSDASection();
543 //Asm->SwitchToSection(LSDASection);
545 Asm->SwitchToDataSection(TAI->getDwarfExceptionSection());
546 Asm->EmitAlignment(2, 0, 0, false);
547 O << "GCC_except_table" << SubprogramCount << ":\n";
549 for (unsigned i = 0; i != SizeAlign; ++i) {
554 EmitLabel("exception", SubprogramCount);
557 Asm->EmitInt8(dwarf::DW_EH_PE_omit);
558 Asm->EOL("LPStart format (DW_EH_PE_omit)");
561 // FIXME: This should default to what the system wants, not just "absptr".
562 if (TypeInfos.empty() && FilterIds.empty()) {
563 Asm->EmitInt8(dwarf::DW_EH_PE_omit);
564 Asm->EOL("TType format (DW_EH_PE_omit)");
566 // FIXME: Instead of using "PreferredEHDataFormat", we should use a simple
567 // approach to determine what needs to happen. Basically, if the target
568 // wants the LSDA to be emitted into a read-only segment (like .text) then
569 // (unless in static mode) it can't output direct pointers to the typeinfo
570 // objects, which may be in an arbitrary locations. Instead, it has to use
571 // and indirect stub pointer to get to the typeinfo.
573 // If the target wants to dump the LSDA's into a segment writable by the
574 // dynamic linker, then it can just use a normal pointer, and the dynamic
575 // linker will fix it up.
577 // TODO: Replace the getDwarfExceptionSection() callback on TAI with a new
578 // getLSDASection() method on TLOF. Merge and sanitize the implementations,
579 // and figure out what the ".gcc_except_table" directive expands to on elf
583 //if (LSDASection->isWritable()) {
584 //Asm->EmitInt8(DW_EH_PE_absptr);
586 //Asm->EmitInt8(DW_EH_PE_pcrel | DW_EH_PE_indirect | DW_EH_PE_sdata4);
589 Asm->EmitInt8(TAI->PreferredEHDataFormat());
592 // FIXME: The comment here should correspond with what PreferredEHDataFormat
594 Asm->EOL("TType format (DW_EH_PE_xxxxx)");
595 Asm->EmitULEB128Bytes(TypeOffset);
596 Asm->EOL("TType base offset");
599 Asm->EmitInt8(dwarf::DW_EH_PE_absptr);
600 Asm->EOL("TType format (DW_EH_PE_absptr)");
601 Asm->EmitULEB128Bytes(TypeOffset);
602 Asm->EOL("TType base offset");
605 Asm->EmitInt8(dwarf::DW_EH_PE_udata4);
606 Asm->EOL("Call site format (DW_EH_PE_udata4)");
607 Asm->EmitULEB128Bytes(SizeSites);
608 Asm->EOL("Call-site table length");
610 // Emit the landing pad site information.
611 for (SmallVectorImpl<CallSiteEntry>::const_iterator
612 I = CallSites.begin(), E = CallSites.end(); I != E; ++I) {
613 const CallSiteEntry &S = *I;
614 const char *BeginTag;
615 unsigned BeginNumber;
618 BeginTag = "eh_func_begin";
619 BeginNumber = SubprogramCount;
622 BeginNumber = S.BeginLabel;
625 EmitSectionOffset(BeginTag, "eh_func_begin", BeginNumber, SubprogramCount,
627 Asm->EOL("Region start");
630 EmitDifference("eh_func_end", SubprogramCount, BeginTag, BeginNumber,
633 EmitDifference("label", S.EndLabel, BeginTag, BeginNumber, true);
635 Asm->EOL("Region length");
640 EmitSectionOffset("label", "eh_func_begin", S.PadLabel, SubprogramCount,
643 Asm->EOL("Landing pad");
645 Asm->EmitULEB128Bytes(S.Action);
650 for (SmallVectorImpl<ActionEntry>::const_iterator
651 I = Actions.begin(), E = Actions.end(); I != E; ++I) {
652 const ActionEntry &Action = *I;
653 Asm->EmitSLEB128Bytes(Action.ValueForTypeID);
654 Asm->EOL("TypeInfo index");
655 Asm->EmitSLEB128Bytes(Action.NextAction);
656 Asm->EOL("Next action");
659 // Emit the type ids.
660 for (std::vector<GlobalVariable *>::const_reverse_iterator
661 I = TypeInfos.rbegin(), E = TypeInfos.rend(); I != E; ++I) {
662 GlobalVariable *GV = *I;
667 O << Asm->getGlobalLinkName(GV, GLN);
672 Asm->EOL("TypeInfo");
675 // Emit the filter typeids.
676 for (std::vector<unsigned>::const_iterator
677 I = FilterIds.begin(), E = FilterIds.end(); I < E; ++I) {
678 unsigned TypeID = *I;
679 Asm->EmitULEB128Bytes(TypeID);
680 Asm->EOL("Filter TypeInfo index");
683 Asm->EmitAlignment(2, 0, 0, false);
686 /// EndModule - Emit all exception information that should come after the
688 void DwarfException::EndModule() {
689 if (TimePassesIsEnabled)
690 ExceptionTimer->startTimer();
692 if (shouldEmitMovesModule || shouldEmitTableModule) {
693 const std::vector<Function *> Personalities = MMI->getPersonalities();
694 for (unsigned i = 0; i < Personalities.size(); ++i)
695 EmitCommonEHFrame(Personalities[i], i);
697 for (std::vector<FunctionEHFrameInfo>::iterator I = EHFrames.begin(),
698 E = EHFrames.end(); I != E; ++I)
702 if (TimePassesIsEnabled)
703 ExceptionTimer->stopTimer();
706 /// BeginFunction - Gather pre-function exception information. Assumes being
707 /// emitted immediately after the function entry point.
708 void DwarfException::BeginFunction(MachineFunction *MF) {
709 if (TimePassesIsEnabled)
710 ExceptionTimer->startTimer();
713 shouldEmitTable = shouldEmitMoves = false;
715 if (MMI && TAI->doesSupportExceptionHandling()) {
716 // Map all labels and get rid of any dead landing pads.
717 MMI->TidyLandingPads();
719 // If any landing pads survive, we need an EH table.
720 if (MMI->getLandingPads().size())
721 shouldEmitTable = true;
723 // See if we need frame move info.
724 if (!MF->getFunction()->doesNotThrow() || UnwindTablesMandatory)
725 shouldEmitMoves = true;
727 if (shouldEmitMoves || shouldEmitTable)
728 // Assumes in correct section after the entry point.
729 EmitLabel("eh_func_begin", ++SubprogramCount);
732 shouldEmitTableModule |= shouldEmitTable;
733 shouldEmitMovesModule |= shouldEmitMoves;
735 if (TimePassesIsEnabled)
736 ExceptionTimer->stopTimer();
739 /// EndFunction - Gather and emit post-function exception information.
741 void DwarfException::EndFunction() {
742 if (TimePassesIsEnabled)
743 ExceptionTimer->startTimer();
745 if (shouldEmitMoves || shouldEmitTable) {
746 EmitLabel("eh_func_end", SubprogramCount);
747 EmitExceptionTable();
749 // Save EH frame information
751 FunctionEHFrameInfo(getAsm()->getCurrentFunctionEHName(MF),
753 MMI->getPersonalityIndex(),
754 MF->getFrameInfo()->hasCalls(),
755 !MMI->getLandingPads().empty(),
756 MMI->getFrameMoves(),
760 if (TimePassesIsEnabled)
761 ExceptionTimer->stopTimer();