1 //===-- CodeGen/AsmPrinter/EHStreamer.cpp - Exception Directive Streamer --===//
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 exception info into assembly files.
12 //===----------------------------------------------------------------------===//
14 #include "EHStreamer.h"
15 #include "llvm/CodeGen/AsmPrinter.h"
16 #include "llvm/CodeGen/MachineFunction.h"
17 #include "llvm/CodeGen/MachineInstr.h"
18 #include "llvm/CodeGen/MachineModuleInfo.h"
19 #include "llvm/IR/Function.h"
20 #include "llvm/MC/MCAsmInfo.h"
21 #include "llvm/MC/MCStreamer.h"
22 #include "llvm/MC/MCSymbol.h"
23 #include "llvm/Support/LEB128.h"
24 #include "llvm/Target/TargetLoweringObjectFile.h"
28 EHStreamer::EHStreamer(AsmPrinter *A) : Asm(A), MMI(Asm->MMI) {}
30 EHStreamer::~EHStreamer() {}
32 /// How many leading type ids two landing pads have in common.
33 unsigned EHStreamer::sharedTypeIDs(const LandingPadInfo *L,
34 const LandingPadInfo *R) {
35 const std::vector<int> &LIds = L->TypeIds, &RIds = R->TypeIds;
36 unsigned LSize = LIds.size(), RSize = RIds.size();
37 unsigned MinSize = LSize < RSize ? LSize : RSize;
40 for (; Count != MinSize; ++Count)
41 if (LIds[Count] != RIds[Count])
47 /// Compute the actions table and gather the first action index for each landing
50 computeActionsTable(const SmallVectorImpl<const LandingPadInfo*> &LandingPads,
51 SmallVectorImpl<ActionEntry> &Actions,
52 SmallVectorImpl<unsigned> &FirstActions) {
54 // The action table follows the call-site table in the LSDA. The individual
55 // records are of two types:
58 // * Exception specification
60 // The two record kinds have the same format, with only small differences.
61 // They are distinguished by the "switch value" field: Catch clauses
62 // (TypeInfos) have strictly positive switch values, and exception
63 // specifications (FilterIds) have strictly negative switch values. Value 0
64 // indicates a catch-all clause.
66 // Negative type IDs index into FilterIds. Positive type IDs index into
67 // TypeInfos. The value written for a positive type ID is just the type ID
68 // itself. For a negative type ID, however, the value written is the
69 // (negative) byte offset of the corresponding FilterIds entry. The byte
70 // offset is usually equal to the type ID (because the FilterIds entries are
71 // written using a variable width encoding, which outputs one byte per entry
72 // as long as the value written is not too large) but can differ. This kind
73 // of complication does not occur for positive type IDs because type infos are
74 // output using a fixed width encoding. FilterOffsets[i] holds the byte
75 // offset corresponding to FilterIds[i].
77 const std::vector<unsigned> &FilterIds = MMI->getFilterIds();
78 SmallVector<int, 16> FilterOffsets;
79 FilterOffsets.reserve(FilterIds.size());
82 for (std::vector<unsigned>::const_iterator
83 I = FilterIds.begin(), E = FilterIds.end(); I != E; ++I) {
84 FilterOffsets.push_back(Offset);
85 Offset -= getULEB128Size(*I);
88 FirstActions.reserve(LandingPads.size());
91 unsigned SizeActions = 0;
92 const LandingPadInfo *PrevLPI = nullptr;
94 for (SmallVectorImpl<const LandingPadInfo *>::const_iterator
95 I = LandingPads.begin(), E = LandingPads.end(); I != E; ++I) {
96 const LandingPadInfo *LPI = *I;
97 const std::vector<int> &TypeIds = LPI->TypeIds;
98 unsigned NumShared = PrevLPI ? sharedTypeIDs(LPI, PrevLPI) : 0;
99 unsigned SizeSiteActions = 0;
101 if (NumShared < TypeIds.size()) {
102 unsigned SizeAction = 0;
103 unsigned PrevAction = (unsigned)-1;
106 unsigned SizePrevIds = PrevLPI->TypeIds.size();
107 assert(Actions.size());
108 PrevAction = Actions.size() - 1;
109 SizeAction = getSLEB128Size(Actions[PrevAction].NextAction) +
110 getSLEB128Size(Actions[PrevAction].ValueForTypeID);
112 for (unsigned j = NumShared; j != SizePrevIds; ++j) {
113 assert(PrevAction != (unsigned)-1 && "PrevAction is invalid!");
114 SizeAction -= getSLEB128Size(Actions[PrevAction].ValueForTypeID);
115 SizeAction += -Actions[PrevAction].NextAction;
116 PrevAction = Actions[PrevAction].Previous;
120 // Compute the actions.
121 for (unsigned J = NumShared, M = TypeIds.size(); J != M; ++J) {
122 int TypeID = TypeIds[J];
123 assert(-1 - TypeID < (int)FilterOffsets.size() && "Unknown filter id!");
124 int ValueForTypeID = TypeID < 0 ? FilterOffsets[-1 - TypeID] : TypeID;
125 unsigned SizeTypeID = getSLEB128Size(ValueForTypeID);
127 int NextAction = SizeAction ? -(SizeAction + SizeTypeID) : 0;
128 SizeAction = SizeTypeID + getSLEB128Size(NextAction);
129 SizeSiteActions += SizeAction;
131 ActionEntry Action = { ValueForTypeID, NextAction, PrevAction };
132 Actions.push_back(Action);
133 PrevAction = Actions.size() - 1;
136 // Record the first action of the landing pad site.
137 FirstAction = SizeActions + SizeSiteActions - SizeAction + 1;
138 } // else identical - re-use previous FirstAction
140 // Information used when created the call-site table. The action record
141 // field of the call site record is the offset of the first associated
142 // action record, relative to the start of the actions table. This value is
143 // biased by 1 (1 indicating the start of the actions table), and 0
144 // indicates that there are no actions.
145 FirstActions.push_back(FirstAction);
147 // Compute this sites contribution to size.
148 SizeActions += SizeSiteActions;
156 /// Return `true' if this is a call to a function marked `nounwind'. Return
157 /// `false' otherwise.
158 bool EHStreamer::callToNoUnwindFunction(const MachineInstr *MI) {
159 assert(MI->isCall() && "This should be a call instruction!");
161 bool MarkedNoUnwind = false;
162 bool SawFunc = false;
164 for (unsigned I = 0, E = MI->getNumOperands(); I != E; ++I) {
165 const MachineOperand &MO = MI->getOperand(I);
167 if (!MO.isGlobal()) continue;
169 const Function *F = dyn_cast<Function>(MO.getGlobal());
173 // Be conservative. If we have more than one function operand for this
174 // call, then we can't make the assumption that it's the callee and
175 // not a parameter to the call.
177 // FIXME: Determine if there's a way to say that `F' is the callee or
179 MarkedNoUnwind = false;
183 MarkedNoUnwind = F->doesNotThrow();
187 return MarkedNoUnwind;
190 /// Compute the call-site table. The entry for an invoke has a try-range
191 /// containing the call, a non-zero landing pad, and an appropriate action. The
192 /// entry for an ordinary call has a try-range containing the call and zero for
193 /// the landing pad and the action. Calls marked 'nounwind' have no entry and
194 /// must not be contained in the try-range of any entry - they form gaps in the
195 /// table. Entries must be ordered by try-range address.
197 computeCallSiteTable(SmallVectorImpl<CallSiteEntry> &CallSites,
198 const SmallVectorImpl<const LandingPadInfo *> &LandingPads,
199 const SmallVectorImpl<unsigned> &FirstActions) {
200 // Invokes and nounwind calls have entries in PadMap (due to being bracketed
201 // by try-range labels when lowered). Ordinary calls do not, so appropriate
202 // try-ranges for them need be deduced so we can put them in the LSDA.
204 for (unsigned i = 0, N = LandingPads.size(); i != N; ++i) {
205 const LandingPadInfo *LandingPad = LandingPads[i];
206 for (unsigned j = 0, E = LandingPad->BeginLabels.size(); j != E; ++j) {
207 MCSymbol *BeginLabel = LandingPad->BeginLabels[j];
208 assert(!PadMap.count(BeginLabel) && "Duplicate landing pad labels!");
209 PadRange P = { i, j };
210 PadMap[BeginLabel] = P;
214 // The end label of the previous invoke or nounwind try-range.
215 MCSymbol *LastLabel = nullptr;
217 // Whether there is a potentially throwing instruction (currently this means
218 // an ordinary call) between the end of the previous try-range and now.
219 bool SawPotentiallyThrowing = false;
221 // Whether the last CallSite entry was for an invoke.
222 bool PreviousIsInvoke = false;
224 bool IsSJLJ = Asm->MAI->getExceptionHandlingType() == ExceptionHandling::SjLj;
226 // Visit all instructions in order of address.
227 for (const auto &MBB : *Asm->MF) {
228 for (const auto &MI : MBB) {
229 if (!MI.isEHLabel()) {
231 SawPotentiallyThrowing |= !callToNoUnwindFunction(&MI);
235 // End of the previous try-range?
236 MCSymbol *BeginLabel = MI.getOperand(0).getMCSymbol();
237 if (BeginLabel == LastLabel)
238 SawPotentiallyThrowing = false;
240 // Beginning of a new try-range?
241 RangeMapType::const_iterator L = PadMap.find(BeginLabel);
242 if (L == PadMap.end())
243 // Nope, it was just some random label.
246 const PadRange &P = L->second;
247 const LandingPadInfo *LandingPad = LandingPads[P.PadIndex];
248 assert(BeginLabel == LandingPad->BeginLabels[P.RangeIndex] &&
249 "Inconsistent landing pad map!");
251 // For Dwarf exception handling (SjLj handling doesn't use this). If some
252 // instruction between the previous try-range and this one may throw,
253 // create a call-site entry with no landing pad for the region between the
255 if (SawPotentiallyThrowing && !IsSJLJ) {
256 CallSiteEntry Site = { LastLabel, BeginLabel, nullptr, 0 };
257 CallSites.push_back(Site);
258 PreviousIsInvoke = false;
261 LastLabel = LandingPad->EndLabels[P.RangeIndex];
262 assert(BeginLabel && LastLabel && "Invalid landing pad!");
264 if (!LandingPad->LandingPadLabel) {
266 PreviousIsInvoke = false;
268 // This try-range is for an invoke.
269 CallSiteEntry Site = {
272 LandingPad->LandingPadLabel,
273 FirstActions[P.PadIndex]
276 // Try to merge with the previous call-site. SJLJ doesn't do this
277 if (PreviousIsInvoke && !IsSJLJ) {
278 CallSiteEntry &Prev = CallSites.back();
279 if (Site.PadLabel == Prev.PadLabel && Site.Action == Prev.Action) {
280 // Extend the range of the previous entry.
281 Prev.EndLabel = Site.EndLabel;
286 // Otherwise, create a new call-site.
288 CallSites.push_back(Site);
290 // SjLj EH must maintain the call sites in the order assigned
291 // to them by the SjLjPrepare pass.
292 unsigned SiteNo = MMI->getCallSiteBeginLabel(BeginLabel);
293 if (CallSites.size() < SiteNo)
294 CallSites.resize(SiteNo);
295 CallSites[SiteNo - 1] = Site;
297 PreviousIsInvoke = true;
302 // If some instruction between the previous try-range and the end of the
303 // function may throw, create a call-site entry with no landing pad for the
304 // region following the try-range.
305 if (SawPotentiallyThrowing && !IsSJLJ) {
306 CallSiteEntry Site = { LastLabel, nullptr, nullptr, 0 };
307 CallSites.push_back(Site);
311 /// Emit landing pads and actions.
313 /// The general organization of the table is complex, but the basic concepts are
314 /// easy. First there is a header which describes the location and organization
315 /// of the three components that follow.
317 /// 1. The landing pad site information describes the range of code covered by
318 /// the try. In our case it's an accumulation of the ranges covered by the
319 /// invokes in the try. There is also a reference to the landing pad that
320 /// handles the exception once processed. Finally an index into the actions
322 /// 2. The action table, in our case, is composed of pairs of type IDs and next
323 /// action offset. Starting with the action index from the landing pad
324 /// site, each type ID is checked for a match to the current exception. If
325 /// it matches then the exception and type id are passed on to the landing
326 /// pad. Otherwise the next action is looked up. This chain is terminated
327 /// with a next action of zero. If no type id is found then the frame is
328 /// unwound and handling continues.
329 /// 3. Type ID table contains references to all the C++ typeinfo for all
330 /// catches in the function. This tables is reverse indexed base 1.
331 void EHStreamer::emitExceptionTable() {
332 const std::vector<const GlobalValue *> &TypeInfos = MMI->getTypeInfos();
333 const std::vector<unsigned> &FilterIds = MMI->getFilterIds();
334 const std::vector<LandingPadInfo> &PadInfos = MMI->getLandingPads();
336 // Sort the landing pads in order of their type ids. This is used to fold
337 // duplicate actions.
338 SmallVector<const LandingPadInfo *, 64> LandingPads;
339 LandingPads.reserve(PadInfos.size());
341 for (unsigned i = 0, N = PadInfos.size(); i != N; ++i)
342 LandingPads.push_back(&PadInfos[i]);
344 // Order landing pads lexicographically by type id.
345 std::sort(LandingPads.begin(), LandingPads.end(),
346 [](const LandingPadInfo *L,
347 const LandingPadInfo *R) { return L->TypeIds < R->TypeIds; });
349 // Compute the actions table and gather the first action index for each
351 SmallVector<ActionEntry, 32> Actions;
352 SmallVector<unsigned, 64> FirstActions;
353 unsigned SizeActions =
354 computeActionsTable(LandingPads, Actions, FirstActions);
356 // Compute the call-site table.
357 SmallVector<CallSiteEntry, 64> CallSites;
358 computeCallSiteTable(CallSites, LandingPads, FirstActions);
363 bool IsSJLJ = Asm->MAI->getExceptionHandlingType() == ExceptionHandling::SjLj;
364 bool HaveTTData = IsSJLJ ? (!TypeInfos.empty() || !FilterIds.empty()) : true;
366 unsigned CallSiteTableLength;
368 CallSiteTableLength = 0;
370 unsigned SiteStartSize = 4; // dwarf::DW_EH_PE_udata4
371 unsigned SiteLengthSize = 4; // dwarf::DW_EH_PE_udata4
372 unsigned LandingPadSize = 4; // dwarf::DW_EH_PE_udata4
373 CallSiteTableLength =
374 CallSites.size() * (SiteStartSize + SiteLengthSize + LandingPadSize);
377 for (unsigned i = 0, e = CallSites.size(); i < e; ++i) {
378 CallSiteTableLength += getULEB128Size(CallSites[i].Action);
380 CallSiteTableLength += getULEB128Size(i);
384 const MCSection *LSDASection = Asm->getObjFileLowering().getLSDASection();
385 unsigned TTypeEncoding;
386 unsigned TypeFormatSize;
389 // For SjLj exceptions, if there is no TypeInfo, then we just explicitly say
390 // that we're omitting that bit.
391 TTypeEncoding = dwarf::DW_EH_PE_omit;
392 // dwarf::DW_EH_PE_absptr
393 TypeFormatSize = Asm->getDataLayout().getPointerSize();
395 // Okay, we have actual filters or typeinfos to emit. As such, we need to
396 // pick a type encoding for them. We're about to emit a list of pointers to
397 // typeinfo objects at the end of the LSDA. However, unless we're in static
398 // mode, this reference will require a relocation by the dynamic linker.
400 // Because of this, we have a couple of options:
402 // 1) If we are in -static mode, we can always use an absolute reference
403 // from the LSDA, because the static linker will resolve it.
405 // 2) Otherwise, if the LSDA section is writable, we can output the direct
406 // reference to the typeinfo and allow the dynamic linker to relocate
407 // it. Since it is in a writable section, the dynamic linker won't
410 // 3) Finally, if we're in PIC mode and the LDSA section isn't writable,
411 // we need to use some form of indirection. For example, on Darwin,
412 // we can output a statically-relocatable reference to a dyld stub. The
413 // offset to the stub is constant, but the contents are in a section
414 // that is updated by the dynamic linker. This is easy enough, but we
415 // need to tell the personality function of the unwinder to indirect
416 // through the dyld stub.
418 // FIXME: When (3) is actually implemented, we'll have to emit the stubs
419 // somewhere. This predicate should be moved to a shared location that is
420 // in target-independent code.
422 TTypeEncoding = Asm->getObjFileLowering().getTTypeEncoding();
423 TypeFormatSize = Asm->GetSizeOfEncodedValue(TTypeEncoding);
426 // Begin the exception table.
427 // Sometimes we want not to emit the data into separate section (e.g. ARM
428 // EHABI). In this case LSDASection will be NULL.
430 Asm->OutStreamer.SwitchSection(LSDASection);
431 Asm->EmitAlignment(2);
435 Asm->OutContext.GetOrCreateSymbol(Twine("GCC_except_table")+
436 Twine(Asm->getFunctionNumber()));
437 Asm->OutStreamer.EmitLabel(GCCETSym);
438 Asm->OutStreamer.EmitLabel(Asm->GetTempSymbol("exception",
439 Asm->getFunctionNumber()));
442 Asm->OutStreamer.EmitLabel(Asm->GetTempSymbol("_LSDA_",
443 Asm->getFunctionNumber()));
445 // Emit the LSDA header.
446 Asm->EmitEncodingByte(dwarf::DW_EH_PE_omit, "@LPStart");
447 Asm->EmitEncodingByte(TTypeEncoding, "@TType");
449 // The type infos need to be aligned. GCC does this by inserting padding just
450 // before the type infos. However, this changes the size of the exception
451 // table, so you need to take this into account when you output the exception
452 // table size. However, the size is output using a variable length encoding.
453 // So by increasing the size by inserting padding, you may increase the number
454 // of bytes used for writing the size. If it increases, say by one byte, then
455 // you now need to output one less byte of padding to get the type infos
456 // aligned. However this decreases the size of the exception table. This
457 // changes the value you have to output for the exception table size. Due to
458 // the variable length encoding, the number of bytes used for writing the
459 // length may decrease. If so, you then have to increase the amount of
460 // padding. And so on. If you look carefully at the GCC code you will see that
461 // it indeed does this in a loop, going on and on until the values stabilize.
462 // We chose another solution: don't output padding inside the table like GCC
463 // does, instead output it before the table.
464 unsigned SizeTypes = TypeInfos.size() * TypeFormatSize;
465 unsigned CallSiteTableLengthSize = getULEB128Size(CallSiteTableLength);
466 unsigned TTypeBaseOffset =
467 sizeof(int8_t) + // Call site format
468 CallSiteTableLengthSize + // Call site table length size
469 CallSiteTableLength + // Call site table length
470 SizeActions + // Actions size
472 unsigned TTypeBaseOffsetSize = getULEB128Size(TTypeBaseOffset);
474 sizeof(int8_t) + // LPStart format
475 sizeof(int8_t) + // TType format
476 (HaveTTData ? TTypeBaseOffsetSize : 0) + // TType base offset size
477 TTypeBaseOffset; // TType base offset
478 unsigned SizeAlign = (4 - TotalSize) & 3;
481 // Account for any extra padding that will be added to the call site table
483 Asm->EmitULEB128(TTypeBaseOffset, "@TType base offset", SizeAlign);
487 bool VerboseAsm = Asm->OutStreamer.isVerboseAsm();
489 // SjLj Exception handling
491 Asm->EmitEncodingByte(dwarf::DW_EH_PE_udata4, "Call site");
493 // Add extra padding if it wasn't added to the TType base offset.
494 Asm->EmitULEB128(CallSiteTableLength, "Call site table length", SizeAlign);
496 // Emit the landing pad site information.
498 for (SmallVectorImpl<CallSiteEntry>::const_iterator
499 I = CallSites.begin(), E = CallSites.end(); I != E; ++I, ++idx) {
500 const CallSiteEntry &S = *I;
502 // Offset of the landing pad, counted in 16-byte bundles relative to the
505 Asm->OutStreamer.AddComment(">> Call Site " + Twine(idx) + " <<");
506 Asm->OutStreamer.AddComment(" On exception at call site "+Twine(idx));
508 Asm->EmitULEB128(idx);
510 // Offset of the first associated action record, relative to the start of
511 // the action table. This value is biased by 1 (1 indicates the start of
512 // the action table), and 0 indicates that there are no actions.
515 Asm->OutStreamer.AddComment(" Action: cleanup");
517 Asm->OutStreamer.AddComment(" Action: " +
518 Twine((S.Action - 1) / 2 + 1));
520 Asm->EmitULEB128(S.Action);
523 // Itanium LSDA exception handling
525 // The call-site table is a list of all call sites that may throw an
526 // exception (including C++ 'throw' statements) in the procedure
527 // fragment. It immediately follows the LSDA header. Each entry indicates,
528 // for a given call, the first corresponding action record and corresponding
531 // The table begins with the number of bytes, stored as an LEB128
532 // compressed, unsigned integer. The records immediately follow the record
533 // count. They are sorted in increasing call-site address. Each record
536 // * The position of the call-site.
537 // * The position of the landing pad.
538 // * The first action record for that call site.
540 // A missing entry in the call-site table indicates that a call is not
541 // supposed to throw.
543 // Emit the landing pad call site table.
544 Asm->EmitEncodingByte(dwarf::DW_EH_PE_udata4, "Call site");
546 // Add extra padding if it wasn't added to the TType base offset.
547 Asm->EmitULEB128(CallSiteTableLength, "Call site table length", SizeAlign);
550 for (SmallVectorImpl<CallSiteEntry>::const_iterator
551 I = CallSites.begin(), E = CallSites.end(); I != E; ++I) {
552 const CallSiteEntry &S = *I;
554 MCSymbol *EHFuncBeginSym =
555 Asm->GetTempSymbol("eh_func_begin", Asm->getFunctionNumber());
557 MCSymbol *BeginLabel = S.BeginLabel;
559 BeginLabel = EHFuncBeginSym;
560 MCSymbol *EndLabel = S.EndLabel;
562 EndLabel = Asm->GetTempSymbol("eh_func_end", Asm->getFunctionNumber());
565 // Offset of the call site relative to the previous call site, counted in
566 // number of 16-byte bundles. The first call site is counted relative to
567 // the start of the procedure fragment.
569 Asm->OutStreamer.AddComment(">> Call Site " + Twine(++Entry) + " <<");
570 Asm->EmitLabelDifference(BeginLabel, EHFuncBeginSym, 4);
572 Asm->OutStreamer.AddComment(Twine(" Call between ") +
573 BeginLabel->getName() + " and " +
574 EndLabel->getName());
575 Asm->EmitLabelDifference(EndLabel, BeginLabel, 4);
577 // Offset of the landing pad, counted in 16-byte bundles relative to the
581 Asm->OutStreamer.AddComment(" has no landing pad");
582 Asm->OutStreamer.EmitIntValue(0, 4/*size*/);
585 Asm->OutStreamer.AddComment(Twine(" jumps to ") +
586 S.PadLabel->getName());
587 Asm->EmitLabelDifference(S.PadLabel, EHFuncBeginSym, 4);
590 // Offset of the first associated action record, relative to the start of
591 // the action table. This value is biased by 1 (1 indicates the start of
592 // the action table), and 0 indicates that there are no actions.
595 Asm->OutStreamer.AddComment(" On action: cleanup");
597 Asm->OutStreamer.AddComment(" On action: " +
598 Twine((S.Action - 1) / 2 + 1));
600 Asm->EmitULEB128(S.Action);
604 // Emit the Action Table.
606 for (SmallVectorImpl<ActionEntry>::const_iterator
607 I = Actions.begin(), E = Actions.end(); I != E; ++I) {
608 const ActionEntry &Action = *I;
611 // Emit comments that decode the action table.
612 Asm->OutStreamer.AddComment(">> Action Record " + Twine(++Entry) + " <<");
617 // Used by the runtime to match the type of the thrown exception to the
618 // type of the catch clauses or the types in the exception specification.
620 if (Action.ValueForTypeID > 0)
621 Asm->OutStreamer.AddComment(" Catch TypeInfo " +
622 Twine(Action.ValueForTypeID));
623 else if (Action.ValueForTypeID < 0)
624 Asm->OutStreamer.AddComment(" Filter TypeInfo " +
625 Twine(Action.ValueForTypeID));
627 Asm->OutStreamer.AddComment(" Cleanup");
629 Asm->EmitSLEB128(Action.ValueForTypeID);
633 // Self-relative signed displacement in bytes of the next action record,
634 // or 0 if there is no next action record.
636 if (Action.NextAction == 0) {
637 Asm->OutStreamer.AddComment(" No further actions");
639 unsigned NextAction = Entry + (Action.NextAction + 1) / 2;
640 Asm->OutStreamer.AddComment(" Continue to action "+Twine(NextAction));
643 Asm->EmitSLEB128(Action.NextAction);
646 emitTypeInfos(TTypeEncoding);
648 Asm->EmitAlignment(2);
651 void EHStreamer::emitTypeInfos(unsigned TTypeEncoding) {
652 const std::vector<const GlobalValue *> &TypeInfos = MMI->getTypeInfos();
653 const std::vector<unsigned> &FilterIds = MMI->getFilterIds();
655 bool VerboseAsm = Asm->OutStreamer.isVerboseAsm();
658 // Emit the Catch TypeInfos.
659 if (VerboseAsm && !TypeInfos.empty()) {
660 Asm->OutStreamer.AddComment(">> Catch TypeInfos <<");
661 Asm->OutStreamer.AddBlankLine();
662 Entry = TypeInfos.size();
665 for (std::vector<const GlobalValue *>::const_reverse_iterator
666 I = TypeInfos.rbegin(), E = TypeInfos.rend(); I != E; ++I) {
667 const GlobalValue *GV = *I;
669 Asm->OutStreamer.AddComment("TypeInfo " + Twine(Entry--));
670 Asm->EmitTTypeReference(GV, TTypeEncoding);
673 // Emit the Exception Specifications.
674 if (VerboseAsm && !FilterIds.empty()) {
675 Asm->OutStreamer.AddComment(">> Filter TypeInfos <<");
676 Asm->OutStreamer.AddBlankLine();
679 for (std::vector<unsigned>::const_iterator
680 I = FilterIds.begin(), E = FilterIds.end(); I < E; ++I) {
681 unsigned TypeID = *I;
685 Asm->OutStreamer.AddComment("FilterInfo " + Twine(Entry));
688 Asm->EmitULEB128(TypeID);
692 /// Emit all exception information that should come after the content.
693 void EHStreamer::endModule() {
694 llvm_unreachable("Should be implemented");
697 /// Gather pre-function exception information. Assumes it's being emitted
698 /// immediately after the function entry point.
699 void EHStreamer::beginFunction(const MachineFunction *MF) {
700 llvm_unreachable("Should be implemented");
703 /// Gather and emit post-function exception information.
704 void EHStreamer::endFunction(const MachineFunction *) {
705 llvm_unreachable("Should be implemented");