blob: 8eb97af0f942a568121598ddc9321c3040cb7bc5 [file] [log] [blame]
Bill Wendlingeb907212009-05-15 01:12:28 +00001//===-- CodeGen/AsmPrinter/DwarfException.cpp - Dwarf Exception Impl ------===//
2//
3// The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// This file contains support for writing dwarf exception info into asm files.
11//
12//===----------------------------------------------------------------------===//
13
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"
28using namespace llvm;
29
30static TimerGroup &getDwarfTimerGroup() {
31 static TimerGroup DwarfTimerGroup("Dwarf Exception");
32 return DwarfTimerGroup;
33}
34
Bill Wendlingbc0d23a2009-05-15 01:18:50 +000035DwarfException::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),
39 ExceptionTimer(0) {
40 if (TimePassesIsEnabled)
41 ExceptionTimer = new Timer("Dwarf Exception Writer",
42 getDwarfTimerGroup());
43}
44
45DwarfException::~DwarfException() {
46 delete ExceptionTimer;
47}
48
Bill Wendlingeb907212009-05-15 01:12:28 +000049void DwarfException::EmitCommonEHFrame(const Function *Personality,
50 unsigned Index) {
51 // Size and sign of stack growth.
52 int stackGrowth =
53 Asm->TM.getFrameInfo()->getStackGrowthDirection() ==
54 TargetFrameInfo::StackGrowsUp ?
55 TD->getPointerSize() : -TD->getPointerSize();
56
57 // Begin eh frame section.
58 Asm->SwitchToTextSection(TAI->getDwarfEHFrameSection());
59
Chris Lattnere2cf37b2009-07-17 20:46:40 +000060 if (TAI->is_EHSymbolPrivate())
61 O << TAI->getPrivateGlobalPrefix();
Bill Wendlingeb907212009-05-15 01:12:28 +000062
63 O << "EH_frame" << Index << ":\n";
64 EmitLabel("section_eh_frame", Index);
65
66 // Define base labels.
67 EmitLabel("eh_frame_common", Index);
68
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");
73
74 // EH frame header.
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");
80
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");
85
86 // Round out reader.
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");
93
94 // If there is a personality, we need to indicate the functions location.
95 if (Personality) {
96 Asm->EmitULEB128Bytes(7);
97 Asm->EOL("Augmentation Size");
98
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)");
103 } else {
104 Asm->EmitInt8(dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4);
105 Asm->EOL("Personality (pcrel sdata4)");
106 }
107
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");
115
116 Asm->EmitInt8(dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4);
117 Asm->EOL("LSDA Encoding (pcrel sdata4)");
118
119 Asm->EmitInt8(dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4);
120 Asm->EOL("FDE Encoding (pcrel sdata4)");
121 } else {
122 Asm->EmitULEB128Bytes(1);
123 Asm->EOL("Augmentation Size");
124
125 Asm->EmitInt8(dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4);
126 Asm->EOL("FDE Encoding (pcrel sdata4)");
127 }
128
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);
133
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,
138 0, 0, false);
139 EmitLabel("eh_frame_common_end", Index);
140
141 Asm->EOL();
142}
143
144/// EmitEHFrame - Emit function exception frame information.
145///
146void DwarfException::EmitEHFrame(const FunctionEHFrameInfo &EHFrameInfo) {
147 assert(!EHFrameInfo.function->hasAvailableExternallyLinkage() &&
148 "Should not emit 'available externally' functions at all");
149
Chris Lattner3e0f60b2009-07-17 21:00:50 +0000150 const Function *TheFunc = EHFrameInfo.function;
151
Bill Wendlingeb907212009-05-15 01:12:28 +0000152 Asm->SwitchToTextSection(TAI->getDwarfEHFrameSection());
153
154 // Externally visible entry into the functions eh frame info. If the
155 // corresponding function is static, this should not be externally visible.
Chris Lattner3e0f60b2009-07-17 21:00:50 +0000156 if (!TheFunc->hasLocalLinkage())
Bill Wendlingeb907212009-05-15 01:12:28 +0000157 if (const char *GlobalEHDirective = TAI->getGlobalEHDirective())
158 O << GlobalEHDirective << EHFrameInfo.FnName << "\n";
Bill Wendlingeb907212009-05-15 01:12:28 +0000159
160 // If corresponding function is weak definition, this should be too.
Chris Lattner3e0f60b2009-07-17 21:00:50 +0000161 if (TheFunc->isWeakForLinker() && TAI->getWeakDefDirective())
Bill Wendlingeb907212009-05-15 01:12:28 +0000162 O << TAI->getWeakDefDirective() << EHFrameInfo.FnName << "\n";
163
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.
Chris Lattner3e0f60b2009-07-17 21:00:50 +0000168 if (!EHFrameInfo.hasCalls && !UnwindTablesMandatory &&
169 (!TheFunc->isWeakForLinker() ||
Bill Wendlingeb907212009-05-15 01:12:28 +0000170 !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";
178 } else {
179 O << EHFrameInfo.FnName << ":\n";
180
181 // EH frame header.
182 EmitDifference("eh_frame_end", EHFrameInfo.Number,
183 "eh_frame_begin", EHFrameInfo.Number, true);
184 Asm->EOL("Length of Frame Information Entry");
185
186 EmitLabel("eh_frame_begin", EHFrameInfo.Number);
187
Chris Lattnera4ff5e42009-07-17 20:53:51 +0000188 EmitSectionOffset("eh_frame_begin", "eh_frame_common",
189 EHFrameInfo.Number, EHFrameInfo.PersonalityIndex,
190 true, true, false);
Bill Wendlingeb907212009-05-15 01:12:28 +0000191
192 Asm->EOL("FDE CIE offset");
193
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");
199
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");
205
206 if (EHFrameInfo.hasLandingPads)
207 EmitReference("exception", EHFrameInfo.Number, true, true);
208 else
209 Asm->EmitInt32((int)0);
210 Asm->EOL("Language Specific Data Area");
211 } else {
212 Asm->EmitULEB128Bytes(0);
213 Asm->EOL("Augmentation size");
214 }
215
216 // Indicate locations of function specific callee saved registers in frame.
217 EmitFrameMoves("eh_func_begin", EHFrameInfo.Number, EHFrameInfo.Moves,
218 true);
219
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,
224 0, 0, false);
225 EmitLabel("eh_frame_end", EHFrameInfo.Number);
226
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.
Chris Lattner401e10c2009-07-20 06:14:25 +0000232 if (MMI->isUsedFunction(EHFrameInfo.function))
Bill Wendlingeb907212009-05-15 01:12:28 +0000233 if (const char *UsedDirective = TAI->getUsedDirective())
234 O << UsedDirective << EHFrameInfo.FnName << "\n\n";
235 }
236}
237
Bill Wendlingeb907212009-05-15 01:12:28 +0000238/// SharedTypeIds - How many leading type ids two landing pads have in common.
239unsigned 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;
244 unsigned Count = 0;
245
246 for (; Count != MinSize; ++Count)
247 if (LIds[Count] != RIds[Count])
248 return Count;
249
250 return Count;
251}
252
253/// PadLT - Order landing pads lexicographically by type id.
254bool 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;
258
259 for (unsigned i = 0; i != MinSize; ++i)
260 if (LIds[i] != RIds[i])
261 return LIds[i] < RIds[i];
262
263 return LSize < RSize;
264}
265
Bill Wendlingd4609622009-07-28 23:23:00 +0000266/// ComputeActionsTable - Compute the actions table and gather the first action
267/// index for each landing pad site.
Bill Wendlingade025c2009-07-29 00:31:35 +0000268unsigned DwarfException::
269ComputeActionsTable(const SmallVectorImpl<const LandingPadInfo*> &LandingPads,
270 SmallVectorImpl<ActionEntry> &Actions,
271 SmallVectorImpl<unsigned> &FirstActions) {
Bill Wendling5e953dd2009-07-28 23:22:13 +0000272 // 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
Bill Wendlingeb907212009-05-15 01:12:28 +0000275 // (negative) byte offset of the corresponding FilterIds entry. The byte
Bill Wendling5e953dd2009-07-28 23:22:13 +0000276 // 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
Bill Wendlingeb907212009-05-15 01:12:28 +0000280 // output using a fixed width encoding. FilterOffsets[i] holds the byte
281 // offset corresponding to FilterIds[i].
Bill Wendling409914b2009-07-29 21:19:44 +0000282
283 const std::vector<unsigned> &FilterIds = MMI->getFilterIds();
Bill Wendlingeb907212009-05-15 01:12:28 +0000284 SmallVector<int, 16> FilterOffsets;
285 FilterOffsets.reserve(FilterIds.size());
286 int Offset = -1;
Bill Wendling409914b2009-07-29 21:19:44 +0000287
288 for (std::vector<unsigned>::const_iterator
289 I = FilterIds.begin(), E = FilterIds.end(); I != E; ++I) {
Bill Wendlingeb907212009-05-15 01:12:28 +0000290 FilterOffsets.push_back(Offset);
291 Offset -= TargetAsmInfo::getULEB128Size(*I);
292 }
293
Bill Wendlingeb907212009-05-15 01:12:28 +0000294 FirstActions.reserve(LandingPads.size());
295
296 int FirstAction = 0;
297 unsigned SizeActions = 0;
Bill Wendling5e953dd2009-07-28 23:22:13 +0000298 const LandingPadInfo *PrevLPI = 0;
Bill Wendling409914b2009-07-29 21:19:44 +0000299
Bill Wendling5cff4872009-07-28 23:44:43 +0000300 for (SmallVectorImpl<const LandingPadInfo *>::const_iterator
Bill Wendling5e953dd2009-07-28 23:22:13 +0000301 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;
Bill Wendlingeb907212009-05-15 01:12:28 +0000305 unsigned SizeSiteActions = 0;
306
307 if (NumShared < TypeIds.size()) {
308 unsigned SizeAction = 0;
309 ActionEntry *PrevAction = 0;
310
311 if (NumShared) {
Bill Wendling5e953dd2009-07-28 23:22:13 +0000312 const unsigned SizePrevIds = PrevLPI->TypeIds.size();
Bill Wendlingeb907212009-05-15 01:12:28 +0000313 assert(Actions.size());
314 PrevAction = &Actions.back();
315 SizeAction = TargetAsmInfo::getSLEB128Size(PrevAction->NextAction) +
316 TargetAsmInfo::getSLEB128Size(PrevAction->ValueForTypeID);
317
318 for (unsigned j = NumShared; j != SizePrevIds; ++j) {
319 SizeAction -=
320 TargetAsmInfo::getSLEB128Size(PrevAction->ValueForTypeID);
321 SizeAction += -PrevAction->NextAction;
322 PrevAction = PrevAction->Previous;
323 }
324 }
325
326 // Compute the actions.
Bill Wendling5e953dd2009-07-28 23:22:13 +0000327 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!");
Bill Wendlingeb907212009-05-15 01:12:28 +0000330 int ValueForTypeID = TypeID < 0 ? FilterOffsets[-1 - TypeID] : TypeID;
331 unsigned SizeTypeID = TargetAsmInfo::getSLEB128Size(ValueForTypeID);
332
333 int NextAction = SizeAction ? -(SizeAction + SizeTypeID) : 0;
334 SizeAction = SizeTypeID + TargetAsmInfo::getSLEB128Size(NextAction);
335 SizeSiteActions += SizeAction;
336
337 ActionEntry Action = {ValueForTypeID, NextAction, PrevAction};
338 Actions.push_back(Action);
Bill Wendlingeb907212009-05-15 01:12:28 +0000339 PrevAction = &Actions.back();
340 }
341
342 // Record the first action of the landing pad site.
343 FirstAction = SizeActions + SizeSiteActions - SizeAction + 1;
344 } // else identical - re-use previous FirstAction
345
346 FirstActions.push_back(FirstAction);
347
348 // Compute this sites contribution to size.
349 SizeActions += SizeSiteActions;
Bill Wendling5e953dd2009-07-28 23:22:13 +0000350
351 PrevLPI = LPI;
Bill Wendlingeb907212009-05-15 01:12:28 +0000352 }
353
Bill Wendling5e953dd2009-07-28 23:22:13 +0000354 return SizeActions;
355}
356
Bill Wendlingade025c2009-07-29 00:31:35 +0000357/// 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.
364void DwarfException::
365ComputeCallSiteTable(SmallVectorImpl<CallSiteEntry> &CallSites,
366 const RangeMapType &PadMap,
367 const SmallVectorImpl<const LandingPadInfo *> &LandingPads,
368 const SmallVectorImpl<unsigned> &FirstActions) {
Bill Wendlingeb907212009-05-15 01:12:28 +0000369 // The end label of the previous invoke or nounwind try-range.
370 unsigned LastLabel = 0;
371
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;
375
Bill Wendling5cff4872009-07-28 23:44:43 +0000376 // Whether the last CallSite entry was for an invoke.
Bill Wendlingeb907212009-05-15 01:12:28 +0000377 bool PreviousIsInvoke = false;
378
379 // Visit all instructions in order of address.
380 for (MachineFunction::const_iterator I = MF->begin(), E = MF->end();
381 I != E; ++I) {
382 for (MachineBasicBlock::const_iterator MI = I->begin(), E = I->end();
383 MI != E; ++MI) {
384 if (!MI->isLabel()) {
385 SawPotentiallyThrowing |= MI->getDesc().isCall();
386 continue;
387 }
388
389 unsigned BeginLabel = MI->getOperand(0).getImm();
390 assert(BeginLabel && "Invalid label!");
391
392 // End of the previous try-range?
393 if (BeginLabel == LastLabel)
394 SawPotentiallyThrowing = false;
395
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.
400 continue;
401
402 PadRange P = L->second;
403 const LandingPadInfo *LandingPad = LandingPads[P.PadIndex];
Bill Wendlingeb907212009-05-15 01:12:28 +0000404 assert(BeginLabel == LandingPad->BeginLabels[P.RangeIndex] &&
405 "Inconsistent landing pad map!");
406
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;
414 }
415
416 LastLabel = LandingPad->EndLabels[P.RangeIndex];
417 assert(BeginLabel && LastLabel && "Invalid landing pad!");
418
419 if (LandingPad->LandingPadLabel) {
420 // This try-range is for an invoke.
421 CallSiteEntry Site = {BeginLabel, LastLabel,
422 LandingPad->LandingPadLabel,
423 FirstActions[P.PadIndex]};
424
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;
431 continue;
432 }
433 }
434
435 // Otherwise, create a new call-site.
436 CallSites.push_back(Site);
437 PreviousIsInvoke = true;
438 } else {
439 // Create a gap.
440 PreviousIsInvoke = false;
441 }
442 }
443 }
444
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);
451 }
Bill Wendlingade025c2009-07-29 00:31:35 +0000452}
453
Bill Wendling0dafca92009-07-29 00:50:05 +0000454/// EmitExceptionTable - Emit landing pads and actions.
455///
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.
459///
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
464/// table.
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.
Bill Wendlingade025c2009-07-29 00:31:35 +0000474void 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;
479
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());
484
485 for (unsigned i = 0, N = PadInfos.size(); i != N; ++i)
486 LandingPads.push_back(&PadInfos[i]);
487
488 std::sort(LandingPads.begin(), LandingPads.end(), PadLT);
489
490 // Compute the actions table and gather the first action index for each
491 // landing pad site.
492 SmallVector<ActionEntry, 32> Actions;
493 SmallVector<unsigned, 64> FirstActions;
494 unsigned SizeActions = ComputeActionsTable(LandingPads, Actions, FirstActions);
495
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.
499 RangeMapType PadMap;
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;
507 }
508 }
509
510 // Compute the call-site table.
511 SmallVector<CallSiteEntry, 64> CallSites;
512 ComputeCallSiteTable(CallSites, PadMap, LandingPads, FirstActions);
Bill Wendlingeb907212009-05-15 01:12:28 +0000513
514 // Final tallies.
515
516 // Call sites.
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 +
521 SiteLengthSize +
522 LandingPadSize);
523 for (unsigned i = 0, e = CallSites.size(); i < e; ++i)
524 SizeSites += TargetAsmInfo::getULEB128Size(CallSites[i].Action);
525
526 // Type infos.
527 const unsigned TypeInfoSize = TD->getPointerSize(); // DW_EH_PE_absptr
528 unsigned SizeTypes = TypeInfos.size() * TypeInfoSize;
529
530 unsigned TypeOffset = sizeof(int8_t) + // Call site format
531 TargetAsmInfo::getULEB128Size(SizeSites) + // Call-site table length
532 SizeSites + SizeActions + SizeTypes;
533
534 unsigned TotalSize = sizeof(int8_t) + // LPStart format
535 sizeof(int8_t) + // TType format
536 TargetAsmInfo::getULEB128Size(TypeOffset) + // TType base offset
537 TypeOffset;
538
539 unsigned SizeAlign = (4 - TotalSize) & 3;
540
541 // Begin the exception table.
Chris Lattner46b754c2009-07-31 22:18:14 +0000542 //MCSection *LSDASection = TAI->getLSDASection();
543 //Asm->SwitchToSection(LSDASection);
544
Bill Wendlingeb907212009-05-15 01:12:28 +0000545 Asm->SwitchToDataSection(TAI->getDwarfExceptionSection());
546 Asm->EmitAlignment(2, 0, 0, false);
547 O << "GCC_except_table" << SubprogramCount << ":\n";
548
549 for (unsigned i = 0; i != SizeAlign; ++i) {
550 Asm->EmitInt8(0);
551 Asm->EOL("Padding");
Bill Wendlingc5800a82009-07-28 21:54:03 +0000552 }
Bill Wendlingeb907212009-05-15 01:12:28 +0000553
554 EmitLabel("exception", SubprogramCount);
555
556 // Emit the header.
557 Asm->EmitInt8(dwarf::DW_EH_PE_omit);
558 Asm->EOL("LPStart format (DW_EH_PE_omit)");
Bill Wendlingb0d9c3e2009-07-28 22:23:45 +0000559
Bill Wendlingade025c2009-07-29 00:31:35 +0000560#if 0
Bill Wendling0dafca92009-07-29 00:50:05 +0000561 // FIXME: This should default to what the system wants, not just "absptr".
Chris Lattner81c9a062009-07-31 22:03:47 +0000562 if (TypeInfos.empty() && FilterIds.empty()) {
563 Asm->EmitInt8(dwarf::DW_EH_PE_omit);
564 Asm->EOL("TType format (DW_EH_PE_omit)");
565 } else {
Chris Lattner46b754c2009-07-31 22:18:14 +0000566 // 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.
572 //
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.
576
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
580 // systems.
581
582 //
583 //if (LSDASection->isWritable()) {
584 //Asm->EmitInt8(DW_EH_PE_absptr);
585 //} else {
586 //Asm->EmitInt8(DW_EH_PE_pcrel | DW_EH_PE_indirect | DW_EH_PE_sdata4);
587 //}
588
Chris Lattner7a01e952009-07-31 21:39:55 +0000589 Asm->EmitInt8(TAI->PreferredEHDataFormat());
Chris Lattner81c9a062009-07-31 22:03:47 +0000590
Chris Lattner46b754c2009-07-31 22:18:14 +0000591
Bill Wendlingb0d9c3e2009-07-28 22:23:45 +0000592 // FIXME: The comment here should correspond with what PreferredEHDataFormat
593 // returned.
594 Asm->EOL("TType format (DW_EH_PE_xxxxx)");
595 Asm->EmitULEB128Bytes(TypeOffset);
596 Asm->EOL("TType base offset");
Bill Wendlingb0d9c3e2009-07-28 22:23:45 +0000597 }
Bill Wendlingade025c2009-07-29 00:31:35 +0000598#else
599 Asm->EmitInt8(dwarf::DW_EH_PE_absptr);
600 Asm->EOL("TType format (DW_EH_PE_absptr)");
Bill Wendling409914b2009-07-29 21:19:44 +0000601 Asm->EmitULEB128Bytes(TypeOffset);
602 Asm->EOL("TType base offset");
Bill Wendlingade025c2009-07-29 00:31:35 +0000603#endif
Bill Wendlingb0d9c3e2009-07-28 22:23:45 +0000604
Bill Wendlingeb907212009-05-15 01:12:28 +0000605 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");
609
610 // Emit the landing pad site information.
Bill Wendling5cff4872009-07-28 23:44:43 +0000611 for (SmallVectorImpl<CallSiteEntry>::const_iterator
612 I = CallSites.begin(), E = CallSites.end(); I != E; ++I) {
613 const CallSiteEntry &S = *I;
Bill Wendlingeb907212009-05-15 01:12:28 +0000614 const char *BeginTag;
615 unsigned BeginNumber;
616
617 if (!S.BeginLabel) {
618 BeginTag = "eh_func_begin";
619 BeginNumber = SubprogramCount;
620 } else {
621 BeginTag = "label";
622 BeginNumber = S.BeginLabel;
623 }
624
625 EmitSectionOffset(BeginTag, "eh_func_begin", BeginNumber, SubprogramCount,
626 true, true);
627 Asm->EOL("Region start");
628
629 if (!S.EndLabel)
630 EmitDifference("eh_func_end", SubprogramCount, BeginTag, BeginNumber,
631 true);
632 else
633 EmitDifference("label", S.EndLabel, BeginTag, BeginNumber, true);
634
635 Asm->EOL("Region length");
636
637 if (!S.PadLabel)
638 Asm->EmitInt32(0);
639 else
640 EmitSectionOffset("label", "eh_func_begin", S.PadLabel, SubprogramCount,
641 true, true);
642
643 Asm->EOL("Landing pad");
644
645 Asm->EmitULEB128Bytes(S.Action);
646 Asm->EOL("Action");
647 }
648
649 // Emit the actions.
Bill Wendling5cff4872009-07-28 23:44:43 +0000650 for (SmallVectorImpl<ActionEntry>::const_iterator
651 I = Actions.begin(), E = Actions.end(); I != E; ++I) {
652 const ActionEntry &Action = *I;
Bill Wendlingeb907212009-05-15 01:12:28 +0000653 Asm->EmitSLEB128Bytes(Action.ValueForTypeID);
654 Asm->EOL("TypeInfo index");
655 Asm->EmitSLEB128Bytes(Action.NextAction);
656 Asm->EOL("Next action");
657 }
658
659 // Emit the type ids.
Bill Wendling5cff4872009-07-28 23:44:43 +0000660 for (std::vector<GlobalVariable *>::const_reverse_iterator
661 I = TypeInfos.rbegin(), E = TypeInfos.rend(); I != E; ++I) {
662 GlobalVariable *GV = *I;
Bill Wendlingeb907212009-05-15 01:12:28 +0000663 PrintRelDirective();
664
665 if (GV) {
666 std::string GLN;
667 O << Asm->getGlobalLinkName(GV, GLN);
668 } else {
669 O << "0";
670 }
671
672 Asm->EOL("TypeInfo");
673 }
674
675 // Emit the filter typeids.
Bill Wendling5cff4872009-07-28 23:44:43 +0000676 for (std::vector<unsigned>::const_iterator
677 I = FilterIds.begin(), E = FilterIds.end(); I < E; ++I) {
678 unsigned TypeID = *I;
Bill Wendlingeb907212009-05-15 01:12:28 +0000679 Asm->EmitULEB128Bytes(TypeID);
680 Asm->EOL("Filter TypeInfo index");
681 }
682
683 Asm->EmitAlignment(2, 0, 0, false);
684}
685
Bill Wendlingeb907212009-05-15 01:12:28 +0000686/// EndModule - Emit all exception information that should come after the
687/// content.
688void DwarfException::EndModule() {
689 if (TimePassesIsEnabled)
690 ExceptionTimer->startTimer();
691
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);
696
697 for (std::vector<FunctionEHFrameInfo>::iterator I = EHFrames.begin(),
698 E = EHFrames.end(); I != E; ++I)
699 EmitEHFrame(*I);
700 }
701
702 if (TimePassesIsEnabled)
703 ExceptionTimer->stopTimer();
704}
705
706/// BeginFunction - Gather pre-function exception information. Assumes being
707/// emitted immediately after the function entry point.
708void DwarfException::BeginFunction(MachineFunction *MF) {
709 if (TimePassesIsEnabled)
710 ExceptionTimer->startTimer();
711
712 this->MF = MF;
713 shouldEmitTable = shouldEmitMoves = false;
714
715 if (MMI && TAI->doesSupportExceptionHandling()) {
716 // Map all labels and get rid of any dead landing pads.
717 MMI->TidyLandingPads();
718
719 // If any landing pads survive, we need an EH table.
720 if (MMI->getLandingPads().size())
721 shouldEmitTable = true;
722
723 // See if we need frame move info.
724 if (!MF->getFunction()->doesNotThrow() || UnwindTablesMandatory)
725 shouldEmitMoves = true;
726
727 if (shouldEmitMoves || shouldEmitTable)
728 // Assumes in correct section after the entry point.
729 EmitLabel("eh_func_begin", ++SubprogramCount);
730 }
731
732 shouldEmitTableModule |= shouldEmitTable;
733 shouldEmitMovesModule |= shouldEmitMoves;
734
735 if (TimePassesIsEnabled)
736 ExceptionTimer->stopTimer();
737}
738
739/// EndFunction - Gather and emit post-function exception information.
740///
741void DwarfException::EndFunction() {
742 if (TimePassesIsEnabled)
743 ExceptionTimer->startTimer();
744
745 if (shouldEmitMoves || shouldEmitTable) {
746 EmitLabel("eh_func_end", SubprogramCount);
747 EmitExceptionTable();
748
749 // Save EH frame information
Bill Wendlingeb907212009-05-15 01:12:28 +0000750 EHFrames.push_back(
Chris Lattnere2cf37b2009-07-17 20:46:40 +0000751 FunctionEHFrameInfo(getAsm()->getCurrentFunctionEHName(MF),
Bill Wendlingeb907212009-05-15 01:12:28 +0000752 SubprogramCount,
753 MMI->getPersonalityIndex(),
754 MF->getFrameInfo()->hasCalls(),
755 !MMI->getLandingPads().empty(),
756 MMI->getFrameMoves(),
757 MF->getFunction()));
758 }
759
760 if (TimePassesIsEnabled)
761 ExceptionTimer->stopTimer();
762}