1 //===- lib/MC/ARMELFStreamer.cpp - ELF Object Output for ARM --------------===//
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 assembles .s files and emits ARM ELF .o object files. Different
11 // from generic ELF streamer in emitting mapping symbols ($a, $t and $d) to
12 // delimit regions of data and code.
13 //
14 //===----------------------------------------------------------------------===//
15
16 #include "ARMRegisterInfo.h"
17 #include "ARMUnwindOpAsm.h"
18 #include "llvm/ADT/StringExtras.h"
19 #include "llvm/ADT/Twine.h"
20 #include "llvm/MC/MCAsmBackend.h"
21 #include "llvm/MC/MCAsmInfo.h"
22 #include "llvm/MC/MCAssembler.h"
23 #include "llvm/MC/MCCodeEmitter.h"
24 #include "llvm/MC/MCContext.h"
25 #include "llvm/MC/MCELFStreamer.h"
26 #include "llvm/MC/MCExpr.h"
27 #include "llvm/MC/MCInst.h"
28 #include "llvm/MC/MCInstPrinter.h"
29 #include "llvm/MC/MCObjectFileInfo.h"
30 #include "llvm/MC/MCObjectStreamer.h"
31 #include "llvm/MC/MCRegisterInfo.h"
32 #include "llvm/MC/MCSection.h"
33 #include "llvm/MC/MCSectionELF.h"
34 #include "llvm/MC/MCStreamer.h"
35 #include "llvm/MC/MCSymbolELF.h"
36 #include "llvm/MC/MCValue.h"
37 #include "llvm/Support/ARMBuildAttributes.h"
38 #include "llvm/Support/ARMEHABI.h"
39 #include "llvm/Support/TargetParser.h"
40 #include "llvm/Support/Debug.h"
41 #include "llvm/Support/ELF.h"
42 #include "llvm/Support/FormattedStream.h"
43 #include "llvm/Support/LEB128.h"
44 #include "llvm/Support/raw_ostream.h"
45 #include <algorithm>
46
47 using namespace llvm;
48
GetAEABIUnwindPersonalityName(unsigned Index)49 static std::string GetAEABIUnwindPersonalityName(unsigned Index) {
50 assert(Index < ARM::EHABI::NUM_PERSONALITY_INDEX &&
51 "Invalid personality index");
52 return (Twine("__aeabi_unwind_cpp_pr") + Twine(Index)).str();
53 }
54
55 namespace {
56
57 class ARMELFStreamer;
58
59 class ARMTargetAsmStreamer : public ARMTargetStreamer {
60 formatted_raw_ostream &OS;
61 MCInstPrinter &InstPrinter;
62 bool IsVerboseAsm;
63
64 void emitFnStart() override;
65 void emitFnEnd() override;
66 void emitCantUnwind() override;
67 void emitPersonality(const MCSymbol *Personality) override;
68 void emitPersonalityIndex(unsigned Index) override;
69 void emitHandlerData() override;
70 void emitSetFP(unsigned FpReg, unsigned SpReg, int64_t Offset = 0) override;
71 void emitMovSP(unsigned Reg, int64_t Offset = 0) override;
72 void emitPad(int64_t Offset) override;
73 void emitRegSave(const SmallVectorImpl<unsigned> &RegList,
74 bool isVector) override;
75 void emitUnwindRaw(int64_t Offset,
76 const SmallVectorImpl<uint8_t> &Opcodes) override;
77
78 void switchVendor(StringRef Vendor) override;
79 void emitAttribute(unsigned Attribute, unsigned Value) override;
80 void emitTextAttribute(unsigned Attribute, StringRef String) override;
81 void emitIntTextAttribute(unsigned Attribute, unsigned IntValue,
82 StringRef StringValue) override;
83 void emitArch(unsigned Arch) override;
84 void emitArchExtension(unsigned ArchExt) override;
85 void emitObjectArch(unsigned Arch) override;
86 void emitFPU(unsigned FPU) override;
87 void emitInst(uint32_t Inst, char Suffix = '\0') override;
88 void finishAttributeSection() override;
89
90 void AnnotateTLSDescriptorSequence(const MCSymbolRefExpr *SRE) override;
91 void emitThumbSet(MCSymbol *Symbol, const MCExpr *Value) override;
92
93 public:
94 ARMTargetAsmStreamer(MCStreamer &S, formatted_raw_ostream &OS,
95 MCInstPrinter &InstPrinter, bool VerboseAsm);
96 };
97
ARMTargetAsmStreamer(MCStreamer & S,formatted_raw_ostream & OS,MCInstPrinter & InstPrinter,bool VerboseAsm)98 ARMTargetAsmStreamer::ARMTargetAsmStreamer(MCStreamer &S,
99 formatted_raw_ostream &OS,
100 MCInstPrinter &InstPrinter,
101 bool VerboseAsm)
102 : ARMTargetStreamer(S), OS(OS), InstPrinter(InstPrinter),
103 IsVerboseAsm(VerboseAsm) {}
emitFnStart()104 void ARMTargetAsmStreamer::emitFnStart() { OS << "\t.fnstart\n"; }
emitFnEnd()105 void ARMTargetAsmStreamer::emitFnEnd() { OS << "\t.fnend\n"; }
emitCantUnwind()106 void ARMTargetAsmStreamer::emitCantUnwind() { OS << "\t.cantunwind\n"; }
emitPersonality(const MCSymbol * Personality)107 void ARMTargetAsmStreamer::emitPersonality(const MCSymbol *Personality) {
108 OS << "\t.personality " << Personality->getName() << '\n';
109 }
emitPersonalityIndex(unsigned Index)110 void ARMTargetAsmStreamer::emitPersonalityIndex(unsigned Index) {
111 OS << "\t.personalityindex " << Index << '\n';
112 }
emitHandlerData()113 void ARMTargetAsmStreamer::emitHandlerData() { OS << "\t.handlerdata\n"; }
emitSetFP(unsigned FpReg,unsigned SpReg,int64_t Offset)114 void ARMTargetAsmStreamer::emitSetFP(unsigned FpReg, unsigned SpReg,
115 int64_t Offset) {
116 OS << "\t.setfp\t";
117 InstPrinter.printRegName(OS, FpReg);
118 OS << ", ";
119 InstPrinter.printRegName(OS, SpReg);
120 if (Offset)
121 OS << ", #" << Offset;
122 OS << '\n';
123 }
emitMovSP(unsigned Reg,int64_t Offset)124 void ARMTargetAsmStreamer::emitMovSP(unsigned Reg, int64_t Offset) {
125 assert((Reg != ARM::SP && Reg != ARM::PC) &&
126 "the operand of .movsp cannot be either sp or pc");
127
128 OS << "\t.movsp\t";
129 InstPrinter.printRegName(OS, Reg);
130 if (Offset)
131 OS << ", #" << Offset;
132 OS << '\n';
133 }
emitPad(int64_t Offset)134 void ARMTargetAsmStreamer::emitPad(int64_t Offset) {
135 OS << "\t.pad\t#" << Offset << '\n';
136 }
emitRegSave(const SmallVectorImpl<unsigned> & RegList,bool isVector)137 void ARMTargetAsmStreamer::emitRegSave(const SmallVectorImpl<unsigned> &RegList,
138 bool isVector) {
139 assert(RegList.size() && "RegList should not be empty");
140 if (isVector)
141 OS << "\t.vsave\t{";
142 else
143 OS << "\t.save\t{";
144
145 InstPrinter.printRegName(OS, RegList[0]);
146
147 for (unsigned i = 1, e = RegList.size(); i != e; ++i) {
148 OS << ", ";
149 InstPrinter.printRegName(OS, RegList[i]);
150 }
151
152 OS << "}\n";
153 }
switchVendor(StringRef Vendor)154 void ARMTargetAsmStreamer::switchVendor(StringRef Vendor) {
155 }
emitAttribute(unsigned Attribute,unsigned Value)156 void ARMTargetAsmStreamer::emitAttribute(unsigned Attribute, unsigned Value) {
157 OS << "\t.eabi_attribute\t" << Attribute << ", " << Twine(Value);
158 if (IsVerboseAsm) {
159 StringRef Name = ARMBuildAttrs::AttrTypeAsString(Attribute);
160 if (!Name.empty())
161 OS << "\t@ " << Name;
162 }
163 OS << "\n";
164 }
emitTextAttribute(unsigned Attribute,StringRef String)165 void ARMTargetAsmStreamer::emitTextAttribute(unsigned Attribute,
166 StringRef String) {
167 switch (Attribute) {
168 case ARMBuildAttrs::CPU_name:
169 OS << "\t.cpu\t" << String.lower();
170 break;
171 default:
172 OS << "\t.eabi_attribute\t" << Attribute << ", \"" << String << "\"";
173 if (IsVerboseAsm) {
174 StringRef Name = ARMBuildAttrs::AttrTypeAsString(Attribute);
175 if (!Name.empty())
176 OS << "\t@ " << Name;
177 }
178 break;
179 }
180 OS << "\n";
181 }
emitIntTextAttribute(unsigned Attribute,unsigned IntValue,StringRef StringValue)182 void ARMTargetAsmStreamer::emitIntTextAttribute(unsigned Attribute,
183 unsigned IntValue,
184 StringRef StringValue) {
185 switch (Attribute) {
186 default: llvm_unreachable("unsupported multi-value attribute in asm mode");
187 case ARMBuildAttrs::compatibility:
188 OS << "\t.eabi_attribute\t" << Attribute << ", " << IntValue;
189 if (!StringValue.empty())
190 OS << ", \"" << StringValue << "\"";
191 if (IsVerboseAsm)
192 OS << "\t@ " << ARMBuildAttrs::AttrTypeAsString(Attribute);
193 break;
194 }
195 OS << "\n";
196 }
emitArch(unsigned Arch)197 void ARMTargetAsmStreamer::emitArch(unsigned Arch) {
198 OS << "\t.arch\t" << ARM::getArchName(Arch) << "\n";
199 }
emitArchExtension(unsigned ArchExt)200 void ARMTargetAsmStreamer::emitArchExtension(unsigned ArchExt) {
201 OS << "\t.arch_extension\t" << ARM::getArchExtName(ArchExt) << "\n";
202 }
emitObjectArch(unsigned Arch)203 void ARMTargetAsmStreamer::emitObjectArch(unsigned Arch) {
204 OS << "\t.object_arch\t" << ARM::getArchName(Arch) << '\n';
205 }
emitFPU(unsigned FPU)206 void ARMTargetAsmStreamer::emitFPU(unsigned FPU) {
207 OS << "\t.fpu\t" << ARM::getFPUName(FPU) << "\n";
208 }
finishAttributeSection()209 void ARMTargetAsmStreamer::finishAttributeSection() {
210 }
211 void
AnnotateTLSDescriptorSequence(const MCSymbolRefExpr * S)212 ARMTargetAsmStreamer::AnnotateTLSDescriptorSequence(const MCSymbolRefExpr *S) {
213 OS << "\t.tlsdescseq\t" << S->getSymbol().getName();
214 }
215
emitThumbSet(MCSymbol * Symbol,const MCExpr * Value)216 void ARMTargetAsmStreamer::emitThumbSet(MCSymbol *Symbol, const MCExpr *Value) {
217 const MCAsmInfo *MAI = Streamer.getContext().getAsmInfo();
218
219 OS << "\t.thumb_set\t";
220 Symbol->print(OS, MAI);
221 OS << ", ";
222 Value->print(OS, MAI);
223 OS << '\n';
224 }
225
emitInst(uint32_t Inst,char Suffix)226 void ARMTargetAsmStreamer::emitInst(uint32_t Inst, char Suffix) {
227 OS << "\t.inst";
228 if (Suffix)
229 OS << "." << Suffix;
230 OS << "\t0x" << Twine::utohexstr(Inst) << "\n";
231 }
232
emitUnwindRaw(int64_t Offset,const SmallVectorImpl<uint8_t> & Opcodes)233 void ARMTargetAsmStreamer::emitUnwindRaw(int64_t Offset,
234 const SmallVectorImpl<uint8_t> &Opcodes) {
235 OS << "\t.unwind_raw " << Offset;
236 for (SmallVectorImpl<uint8_t>::const_iterator OCI = Opcodes.begin(),
237 OCE = Opcodes.end();
238 OCI != OCE; ++OCI)
239 OS << ", 0x" << Twine::utohexstr(*OCI);
240 OS << '\n';
241 }
242
243 class ARMTargetELFStreamer : public ARMTargetStreamer {
244 private:
245 // This structure holds all attributes, accounting for
246 // their string/numeric value, so we can later emit them
247 // in declaration order, keeping all in the same vector
248 struct AttributeItem {
249 enum {
250 HiddenAttribute = 0,
251 NumericAttribute,
252 TextAttribute,
253 NumericAndTextAttributes
254 } Type;
255 unsigned Tag;
256 unsigned IntValue;
257 std::string StringValue;
258
LessTag__anon852c50f70111::ARMTargetELFStreamer::AttributeItem259 static bool LessTag(const AttributeItem &LHS, const AttributeItem &RHS) {
260 // The conformance tag must be emitted first when serialised
261 // into an object file. Specifically, the addenda to the ARM ABI
262 // states that (2.3.7.4):
263 //
264 // "To simplify recognition by consumers in the common case of
265 // claiming conformity for the whole file, this tag should be
266 // emitted first in a file-scope sub-subsection of the first
267 // public subsection of the attributes section."
268 //
269 // So it is special-cased in this comparison predicate when the
270 // attributes are sorted in finishAttributeSection().
271 return (RHS.Tag != ARMBuildAttrs::conformance) &&
272 ((LHS.Tag == ARMBuildAttrs::conformance) || (LHS.Tag < RHS.Tag));
273 }
274 };
275
276 StringRef CurrentVendor;
277 unsigned FPU;
278 unsigned Arch;
279 unsigned EmittedArch;
280 SmallVector<AttributeItem, 64> Contents;
281
282 MCSection *AttributeSection;
283
getAttributeItem(unsigned Attribute)284 AttributeItem *getAttributeItem(unsigned Attribute) {
285 for (size_t i = 0; i < Contents.size(); ++i)
286 if (Contents[i].Tag == Attribute)
287 return &Contents[i];
288 return nullptr;
289 }
290
setAttributeItem(unsigned Attribute,unsigned Value,bool OverwriteExisting)291 void setAttributeItem(unsigned Attribute, unsigned Value,
292 bool OverwriteExisting) {
293 // Look for existing attribute item
294 if (AttributeItem *Item = getAttributeItem(Attribute)) {
295 if (!OverwriteExisting)
296 return;
297 Item->Type = AttributeItem::NumericAttribute;
298 Item->IntValue = Value;
299 return;
300 }
301
302 // Create new attribute item
303 AttributeItem Item = {
304 AttributeItem::NumericAttribute,
305 Attribute,
306 Value,
307 StringRef("")
308 };
309 Contents.push_back(Item);
310 }
311
setAttributeItem(unsigned Attribute,StringRef Value,bool OverwriteExisting)312 void setAttributeItem(unsigned Attribute, StringRef Value,
313 bool OverwriteExisting) {
314 // Look for existing attribute item
315 if (AttributeItem *Item = getAttributeItem(Attribute)) {
316 if (!OverwriteExisting)
317 return;
318 Item->Type = AttributeItem::TextAttribute;
319 Item->StringValue = Value;
320 return;
321 }
322
323 // Create new attribute item
324 AttributeItem Item = {
325 AttributeItem::TextAttribute,
326 Attribute,
327 0,
328 Value
329 };
330 Contents.push_back(Item);
331 }
332
setAttributeItems(unsigned Attribute,unsigned IntValue,StringRef StringValue,bool OverwriteExisting)333 void setAttributeItems(unsigned Attribute, unsigned IntValue,
334 StringRef StringValue, bool OverwriteExisting) {
335 // Look for existing attribute item
336 if (AttributeItem *Item = getAttributeItem(Attribute)) {
337 if (!OverwriteExisting)
338 return;
339 Item->Type = AttributeItem::NumericAndTextAttributes;
340 Item->IntValue = IntValue;
341 Item->StringValue = StringValue;
342 return;
343 }
344
345 // Create new attribute item
346 AttributeItem Item = {
347 AttributeItem::NumericAndTextAttributes,
348 Attribute,
349 IntValue,
350 StringValue
351 };
352 Contents.push_back(Item);
353 }
354
355 void emitArchDefaultAttributes();
356 void emitFPUDefaultAttributes();
357
358 ARMELFStreamer &getStreamer();
359
360 void emitFnStart() override;
361 void emitFnEnd() override;
362 void emitCantUnwind() override;
363 void emitPersonality(const MCSymbol *Personality) override;
364 void emitPersonalityIndex(unsigned Index) override;
365 void emitHandlerData() override;
366 void emitSetFP(unsigned FpReg, unsigned SpReg, int64_t Offset = 0) override;
367 void emitMovSP(unsigned Reg, int64_t Offset = 0) override;
368 void emitPad(int64_t Offset) override;
369 void emitRegSave(const SmallVectorImpl<unsigned> &RegList,
370 bool isVector) override;
371 void emitUnwindRaw(int64_t Offset,
372 const SmallVectorImpl<uint8_t> &Opcodes) override;
373
374 void switchVendor(StringRef Vendor) override;
375 void emitAttribute(unsigned Attribute, unsigned Value) override;
376 void emitTextAttribute(unsigned Attribute, StringRef String) override;
377 void emitIntTextAttribute(unsigned Attribute, unsigned IntValue,
378 StringRef StringValue) override;
379 void emitArch(unsigned Arch) override;
380 void emitObjectArch(unsigned Arch) override;
381 void emitFPU(unsigned FPU) override;
382 void emitInst(uint32_t Inst, char Suffix = '\0') override;
383 void finishAttributeSection() override;
384 void emitLabel(MCSymbol *Symbol) override;
385
386 void AnnotateTLSDescriptorSequence(const MCSymbolRefExpr *SRE) override;
387 void emitThumbSet(MCSymbol *Symbol, const MCExpr *Value) override;
388
389 size_t calculateContentSize() const;
390
391 public:
ARMTargetELFStreamer(MCStreamer & S)392 ARMTargetELFStreamer(MCStreamer &S)
393 : ARMTargetStreamer(S), CurrentVendor("aeabi"), FPU(ARM::FK_INVALID),
394 Arch(ARM::AK_INVALID), EmittedArch(ARM::AK_INVALID),
395 AttributeSection(nullptr) {}
396 };
397
398 /// Extend the generic ELFStreamer class so that it can emit mapping symbols at
399 /// the appropriate points in the object files. These symbols are defined in the
400 /// ARM ELF ABI: infocenter.arm.com/help/topic/com.arm.../IHI0044D_aaelf.pdf.
401 ///
402 /// In brief: $a, $t or $d should be emitted at the start of each contiguous
403 /// region of ARM code, Thumb code or data in a section. In practice, this
404 /// emission does not rely on explicit assembler directives but on inherent
405 /// properties of the directives doing the emission (e.g. ".byte" is data, "add
406 /// r0, r0, r0" an instruction).
407 ///
408 /// As a result this system is orthogonal to the DataRegion infrastructure used
409 /// by MachO. Beware!
410 class ARMELFStreamer : public MCELFStreamer {
411 public:
412 friend class ARMTargetELFStreamer;
413
ARMELFStreamer(MCContext & Context,MCAsmBackend & TAB,raw_pwrite_stream & OS,MCCodeEmitter * Emitter,bool IsThumb)414 ARMELFStreamer(MCContext &Context, MCAsmBackend &TAB, raw_pwrite_stream &OS,
415 MCCodeEmitter *Emitter, bool IsThumb)
416 : MCELFStreamer(Context, TAB, OS, Emitter), IsThumb(IsThumb),
417 MappingSymbolCounter(0), LastEMS(EMS_None) {
418 Reset();
419 }
420
~ARMELFStreamer()421 ~ARMELFStreamer() {}
422
423 void FinishImpl() override;
424
425 // ARM exception handling directives
426 void emitFnStart();
427 void emitFnEnd();
428 void emitCantUnwind();
429 void emitPersonality(const MCSymbol *Per);
430 void emitPersonalityIndex(unsigned index);
431 void emitHandlerData();
432 void emitSetFP(unsigned NewFpReg, unsigned NewSpReg, int64_t Offset = 0);
433 void emitMovSP(unsigned Reg, int64_t Offset = 0);
434 void emitPad(int64_t Offset);
435 void emitRegSave(const SmallVectorImpl<unsigned> &RegList, bool isVector);
436 void emitUnwindRaw(int64_t Offset, const SmallVectorImpl<uint8_t> &Opcodes);
437
ChangeSection(MCSection * Section,const MCExpr * Subsection)438 void ChangeSection(MCSection *Section, const MCExpr *Subsection) override {
439 // We have to keep track of the mapping symbol state of any sections we
440 // use. Each one should start off as EMS_None, which is provided as the
441 // default constructor by DenseMap::lookup.
442 LastMappingSymbols[getPreviousSection().first] = LastEMS;
443 LastEMS = LastMappingSymbols.lookup(Section);
444
445 MCELFStreamer::ChangeSection(Section, Subsection);
446 }
447
448 /// This function is the one used to emit instruction data into the ELF
449 /// streamer. We override it to add the appropriate mapping symbol if
450 /// necessary.
EmitInstruction(const MCInst & Inst,const MCSubtargetInfo & STI)451 void EmitInstruction(const MCInst& Inst,
452 const MCSubtargetInfo &STI) override {
453 if (IsThumb)
454 EmitThumbMappingSymbol();
455 else
456 EmitARMMappingSymbol();
457
458 MCELFStreamer::EmitInstruction(Inst, STI);
459 }
460
emitInst(uint32_t Inst,char Suffix)461 void emitInst(uint32_t Inst, char Suffix) {
462 unsigned Size;
463 char Buffer[4];
464 const bool LittleEndian = getContext().getAsmInfo()->isLittleEndian();
465
466 switch (Suffix) {
467 case '\0':
468 Size = 4;
469
470 assert(!IsThumb);
471 EmitARMMappingSymbol();
472 for (unsigned II = 0, IE = Size; II != IE; II++) {
473 const unsigned I = LittleEndian ? (Size - II - 1) : II;
474 Buffer[Size - II - 1] = uint8_t(Inst >> I * CHAR_BIT);
475 }
476
477 break;
478 case 'n':
479 case 'w':
480 Size = (Suffix == 'n' ? 2 : 4);
481
482 assert(IsThumb);
483 EmitThumbMappingSymbol();
484 for (unsigned II = 0, IE = Size; II != IE; II = II + 2) {
485 const unsigned I0 = LittleEndian ? II + 0 : (Size - II - 1);
486 const unsigned I1 = LittleEndian ? II + 1 : (Size - II - 2);
487 Buffer[Size - II - 2] = uint8_t(Inst >> I0 * CHAR_BIT);
488 Buffer[Size - II - 1] = uint8_t(Inst >> I1 * CHAR_BIT);
489 }
490
491 break;
492 default:
493 llvm_unreachable("Invalid Suffix");
494 }
495
496 MCELFStreamer::EmitBytes(StringRef(Buffer, Size));
497 }
498
499 /// This is one of the functions used to emit data into an ELF section, so the
500 /// ARM streamer overrides it to add the appropriate mapping symbol ($d) if
501 /// necessary.
EmitBytes(StringRef Data)502 void EmitBytes(StringRef Data) override {
503 EmitDataMappingSymbol();
504 MCELFStreamer::EmitBytes(Data);
505 }
506
507 /// This is one of the functions used to emit data into an ELF section, so the
508 /// ARM streamer overrides it to add the appropriate mapping symbol ($d) if
509 /// necessary.
EmitValueImpl(const MCExpr * Value,unsigned Size,SMLoc Loc)510 void EmitValueImpl(const MCExpr *Value, unsigned Size, SMLoc Loc) override {
511 if (const MCSymbolRefExpr *SRE = dyn_cast_or_null<MCSymbolRefExpr>(Value))
512 if (SRE->getKind() == MCSymbolRefExpr::VK_ARM_SBREL && !(Size == 4)) {
513 getContext().reportError(Loc, "relocated expression must be 32-bit");
514 return;
515 }
516
517 EmitDataMappingSymbol();
518 MCELFStreamer::EmitValueImpl(Value, Size, Loc);
519 }
520
EmitAssemblerFlag(MCAssemblerFlag Flag)521 void EmitAssemblerFlag(MCAssemblerFlag Flag) override {
522 MCELFStreamer::EmitAssemblerFlag(Flag);
523
524 switch (Flag) {
525 case MCAF_SyntaxUnified:
526 return; // no-op here.
527 case MCAF_Code16:
528 IsThumb = true;
529 return; // Change to Thumb mode
530 case MCAF_Code32:
531 IsThumb = false;
532 return; // Change to ARM mode
533 case MCAF_Code64:
534 return;
535 case MCAF_SubsectionsViaSymbols:
536 return;
537 }
538 }
539
540 private:
541 enum ElfMappingSymbol {
542 EMS_None,
543 EMS_ARM,
544 EMS_Thumb,
545 EMS_Data
546 };
547
EmitDataMappingSymbol()548 void EmitDataMappingSymbol() {
549 if (LastEMS == EMS_Data) return;
550 EmitMappingSymbol("$d");
551 LastEMS = EMS_Data;
552 }
553
EmitThumbMappingSymbol()554 void EmitThumbMappingSymbol() {
555 if (LastEMS == EMS_Thumb) return;
556 EmitMappingSymbol("$t");
557 LastEMS = EMS_Thumb;
558 }
559
EmitARMMappingSymbol()560 void EmitARMMappingSymbol() {
561 if (LastEMS == EMS_ARM) return;
562 EmitMappingSymbol("$a");
563 LastEMS = EMS_ARM;
564 }
565
EmitMappingSymbol(StringRef Name)566 void EmitMappingSymbol(StringRef Name) {
567 auto *Symbol = cast<MCSymbolELF>(getContext().getOrCreateSymbol(
568 Name + "." + Twine(MappingSymbolCounter++)));
569 EmitLabel(Symbol);
570
571 Symbol->setType(ELF::STT_NOTYPE);
572 Symbol->setBinding(ELF::STB_LOCAL);
573 Symbol->setExternal(false);
574 }
575
EmitThumbFunc(MCSymbol * Func)576 void EmitThumbFunc(MCSymbol *Func) override {
577 getAssembler().setIsThumbFunc(Func);
578 EmitSymbolAttribute(Func, MCSA_ELF_TypeFunction);
579 }
580
581 // Helper functions for ARM exception handling directives
582 void Reset();
583
584 void EmitPersonalityFixup(StringRef Name);
585 void FlushPendingOffset();
586 void FlushUnwindOpcodes(bool NoHandlerData);
587
588 void SwitchToEHSection(const char *Prefix, unsigned Type, unsigned Flags,
589 SectionKind Kind, const MCSymbol &Fn);
590 void SwitchToExTabSection(const MCSymbol &FnStart);
591 void SwitchToExIdxSection(const MCSymbol &FnStart);
592
593 void EmitFixup(const MCExpr *Expr, MCFixupKind Kind);
594
595 bool IsThumb;
596 int64_t MappingSymbolCounter;
597
598 DenseMap<const MCSection *, ElfMappingSymbol> LastMappingSymbols;
599 ElfMappingSymbol LastEMS;
600
601 // ARM Exception Handling Frame Information
602 MCSymbol *ExTab;
603 MCSymbol *FnStart;
604 const MCSymbol *Personality;
605 unsigned PersonalityIndex;
606 unsigned FPReg; // Frame pointer register
607 int64_t FPOffset; // Offset: (final frame pointer) - (initial $sp)
608 int64_t SPOffset; // Offset: (final $sp) - (initial $sp)
609 int64_t PendingOffset; // Offset: (final $sp) - (emitted $sp)
610 bool UsedFP;
611 bool CantUnwind;
612 SmallVector<uint8_t, 64> Opcodes;
613 UnwindOpcodeAssembler UnwindOpAsm;
614 };
615 } // end anonymous namespace
616
getStreamer()617 ARMELFStreamer &ARMTargetELFStreamer::getStreamer() {
618 return static_cast<ARMELFStreamer &>(Streamer);
619 }
620
emitFnStart()621 void ARMTargetELFStreamer::emitFnStart() { getStreamer().emitFnStart(); }
emitFnEnd()622 void ARMTargetELFStreamer::emitFnEnd() { getStreamer().emitFnEnd(); }
emitCantUnwind()623 void ARMTargetELFStreamer::emitCantUnwind() { getStreamer().emitCantUnwind(); }
emitPersonality(const MCSymbol * Personality)624 void ARMTargetELFStreamer::emitPersonality(const MCSymbol *Personality) {
625 getStreamer().emitPersonality(Personality);
626 }
emitPersonalityIndex(unsigned Index)627 void ARMTargetELFStreamer::emitPersonalityIndex(unsigned Index) {
628 getStreamer().emitPersonalityIndex(Index);
629 }
emitHandlerData()630 void ARMTargetELFStreamer::emitHandlerData() {
631 getStreamer().emitHandlerData();
632 }
emitSetFP(unsigned FpReg,unsigned SpReg,int64_t Offset)633 void ARMTargetELFStreamer::emitSetFP(unsigned FpReg, unsigned SpReg,
634 int64_t Offset) {
635 getStreamer().emitSetFP(FpReg, SpReg, Offset);
636 }
emitMovSP(unsigned Reg,int64_t Offset)637 void ARMTargetELFStreamer::emitMovSP(unsigned Reg, int64_t Offset) {
638 getStreamer().emitMovSP(Reg, Offset);
639 }
emitPad(int64_t Offset)640 void ARMTargetELFStreamer::emitPad(int64_t Offset) {
641 getStreamer().emitPad(Offset);
642 }
emitRegSave(const SmallVectorImpl<unsigned> & RegList,bool isVector)643 void ARMTargetELFStreamer::emitRegSave(const SmallVectorImpl<unsigned> &RegList,
644 bool isVector) {
645 getStreamer().emitRegSave(RegList, isVector);
646 }
emitUnwindRaw(int64_t Offset,const SmallVectorImpl<uint8_t> & Opcodes)647 void ARMTargetELFStreamer::emitUnwindRaw(int64_t Offset,
648 const SmallVectorImpl<uint8_t> &Opcodes) {
649 getStreamer().emitUnwindRaw(Offset, Opcodes);
650 }
switchVendor(StringRef Vendor)651 void ARMTargetELFStreamer::switchVendor(StringRef Vendor) {
652 assert(!Vendor.empty() && "Vendor cannot be empty.");
653
654 if (CurrentVendor == Vendor)
655 return;
656
657 if (!CurrentVendor.empty())
658 finishAttributeSection();
659
660 assert(Contents.empty() &&
661 ".ARM.attributes should be flushed before changing vendor");
662 CurrentVendor = Vendor;
663
664 }
emitAttribute(unsigned Attribute,unsigned Value)665 void ARMTargetELFStreamer::emitAttribute(unsigned Attribute, unsigned Value) {
666 setAttributeItem(Attribute, Value, /* OverwriteExisting= */ true);
667 }
emitTextAttribute(unsigned Attribute,StringRef Value)668 void ARMTargetELFStreamer::emitTextAttribute(unsigned Attribute,
669 StringRef Value) {
670 setAttributeItem(Attribute, Value, /* OverwriteExisting= */ true);
671 }
emitIntTextAttribute(unsigned Attribute,unsigned IntValue,StringRef StringValue)672 void ARMTargetELFStreamer::emitIntTextAttribute(unsigned Attribute,
673 unsigned IntValue,
674 StringRef StringValue) {
675 setAttributeItems(Attribute, IntValue, StringValue,
676 /* OverwriteExisting= */ true);
677 }
emitArch(unsigned Value)678 void ARMTargetELFStreamer::emitArch(unsigned Value) {
679 Arch = Value;
680 }
emitObjectArch(unsigned Value)681 void ARMTargetELFStreamer::emitObjectArch(unsigned Value) {
682 EmittedArch = Value;
683 }
emitArchDefaultAttributes()684 void ARMTargetELFStreamer::emitArchDefaultAttributes() {
685 using namespace ARMBuildAttrs;
686
687 setAttributeItem(CPU_name,
688 ARM::getCPUAttr(Arch),
689 false);
690
691 if (EmittedArch == ARM::AK_INVALID)
692 setAttributeItem(CPU_arch,
693 ARM::getArchAttr(Arch),
694 false);
695 else
696 setAttributeItem(CPU_arch,
697 ARM::getArchAttr(EmittedArch),
698 false);
699
700 switch (Arch) {
701 case ARM::AK_ARMV2:
702 case ARM::AK_ARMV2A:
703 case ARM::AK_ARMV3:
704 case ARM::AK_ARMV3M:
705 case ARM::AK_ARMV4:
706 setAttributeItem(ARM_ISA_use, Allowed, false);
707 break;
708
709 case ARM::AK_ARMV4T:
710 case ARM::AK_ARMV5T:
711 case ARM::AK_ARMV5TE:
712 case ARM::AK_ARMV6:
713 setAttributeItem(ARM_ISA_use, Allowed, false);
714 setAttributeItem(THUMB_ISA_use, Allowed, false);
715 break;
716
717 case ARM::AK_ARMV6T2:
718 setAttributeItem(ARM_ISA_use, Allowed, false);
719 setAttributeItem(THUMB_ISA_use, AllowThumb32, false);
720 break;
721
722 case ARM::AK_ARMV6K:
723 case ARM::AK_ARMV6KZ:
724 setAttributeItem(ARM_ISA_use, Allowed, false);
725 setAttributeItem(THUMB_ISA_use, Allowed, false);
726 setAttributeItem(Virtualization_use, AllowTZ, false);
727 break;
728
729 case ARM::AK_ARMV6M:
730 setAttributeItem(THUMB_ISA_use, Allowed, false);
731 break;
732
733 case ARM::AK_ARMV7A:
734 setAttributeItem(CPU_arch_profile, ApplicationProfile, false);
735 setAttributeItem(ARM_ISA_use, Allowed, false);
736 setAttributeItem(THUMB_ISA_use, AllowThumb32, false);
737 break;
738
739 case ARM::AK_ARMV7R:
740 setAttributeItem(CPU_arch_profile, RealTimeProfile, false);
741 setAttributeItem(ARM_ISA_use, Allowed, false);
742 setAttributeItem(THUMB_ISA_use, AllowThumb32, false);
743 break;
744
745 case ARM::AK_ARMV7M:
746 setAttributeItem(CPU_arch_profile, MicroControllerProfile, false);
747 setAttributeItem(THUMB_ISA_use, AllowThumb32, false);
748 break;
749
750 case ARM::AK_ARMV8A:
751 case ARM::AK_ARMV8_1A:
752 case ARM::AK_ARMV8_2A:
753 setAttributeItem(CPU_arch_profile, ApplicationProfile, false);
754 setAttributeItem(ARM_ISA_use, Allowed, false);
755 setAttributeItem(THUMB_ISA_use, AllowThumb32, false);
756 setAttributeItem(MPextension_use, Allowed, false);
757 setAttributeItem(Virtualization_use, AllowTZVirtualization, false);
758 break;
759
760 case ARM::AK_IWMMXT:
761 setAttributeItem(ARM_ISA_use, Allowed, false);
762 setAttributeItem(THUMB_ISA_use, Allowed, false);
763 setAttributeItem(WMMX_arch, AllowWMMXv1, false);
764 break;
765
766 case ARM::AK_IWMMXT2:
767 setAttributeItem(ARM_ISA_use, Allowed, false);
768 setAttributeItem(THUMB_ISA_use, Allowed, false);
769 setAttributeItem(WMMX_arch, AllowWMMXv2, false);
770 break;
771
772 default:
773 report_fatal_error("Unknown Arch: " + Twine(Arch));
774 break;
775 }
776 }
emitFPU(unsigned Value)777 void ARMTargetELFStreamer::emitFPU(unsigned Value) {
778 FPU = Value;
779 }
emitFPUDefaultAttributes()780 void ARMTargetELFStreamer::emitFPUDefaultAttributes() {
781 switch (FPU) {
782 case ARM::FK_VFP:
783 case ARM::FK_VFPV2:
784 setAttributeItem(ARMBuildAttrs::FP_arch,
785 ARMBuildAttrs::AllowFPv2,
786 /* OverwriteExisting= */ false);
787 break;
788
789 case ARM::FK_VFPV3:
790 setAttributeItem(ARMBuildAttrs::FP_arch,
791 ARMBuildAttrs::AllowFPv3A,
792 /* OverwriteExisting= */ false);
793 break;
794
795 case ARM::FK_VFPV3_FP16:
796 setAttributeItem(ARMBuildAttrs::FP_arch,
797 ARMBuildAttrs::AllowFPv3A,
798 /* OverwriteExisting= */ false);
799 setAttributeItem(ARMBuildAttrs::FP_HP_extension,
800 ARMBuildAttrs::AllowHPFP,
801 /* OverwriteExisting= */ false);
802 break;
803
804 case ARM::FK_VFPV3_D16:
805 setAttributeItem(ARMBuildAttrs::FP_arch,
806 ARMBuildAttrs::AllowFPv3B,
807 /* OverwriteExisting= */ false);
808 break;
809
810 case ARM::FK_VFPV3_D16_FP16:
811 setAttributeItem(ARMBuildAttrs::FP_arch,
812 ARMBuildAttrs::AllowFPv3B,
813 /* OverwriteExisting= */ false);
814 setAttributeItem(ARMBuildAttrs::FP_HP_extension,
815 ARMBuildAttrs::AllowHPFP,
816 /* OverwriteExisting= */ false);
817 break;
818
819 case ARM::FK_VFPV3XD:
820 setAttributeItem(ARMBuildAttrs::FP_arch,
821 ARMBuildAttrs::AllowFPv3B,
822 /* OverwriteExisting= */ false);
823 break;
824 case ARM::FK_VFPV3XD_FP16:
825 setAttributeItem(ARMBuildAttrs::FP_arch,
826 ARMBuildAttrs::AllowFPv3B,
827 /* OverwriteExisting= */ false);
828 setAttributeItem(ARMBuildAttrs::FP_HP_extension,
829 ARMBuildAttrs::AllowHPFP,
830 /* OverwriteExisting= */ false);
831 break;
832
833 case ARM::FK_VFPV4:
834 setAttributeItem(ARMBuildAttrs::FP_arch,
835 ARMBuildAttrs::AllowFPv4A,
836 /* OverwriteExisting= */ false);
837 break;
838
839 // ABI_HardFP_use is handled in ARMAsmPrinter, so _SP_D16 is treated the same
840 // as _D16 here.
841 case ARM::FK_FPV4_SP_D16:
842 case ARM::FK_VFPV4_D16:
843 setAttributeItem(ARMBuildAttrs::FP_arch,
844 ARMBuildAttrs::AllowFPv4B,
845 /* OverwriteExisting= */ false);
846 break;
847
848 case ARM::FK_FP_ARMV8:
849 setAttributeItem(ARMBuildAttrs::FP_arch,
850 ARMBuildAttrs::AllowFPARMv8A,
851 /* OverwriteExisting= */ false);
852 break;
853
854 // FPV5_D16 is identical to FP_ARMV8 except for the number of D registers, so
855 // uses the FP_ARMV8_D16 build attribute.
856 case ARM::FK_FPV5_SP_D16:
857 case ARM::FK_FPV5_D16:
858 setAttributeItem(ARMBuildAttrs::FP_arch,
859 ARMBuildAttrs::AllowFPARMv8B,
860 /* OverwriteExisting= */ false);
861 break;
862
863 case ARM::FK_NEON:
864 setAttributeItem(ARMBuildAttrs::FP_arch,
865 ARMBuildAttrs::AllowFPv3A,
866 /* OverwriteExisting= */ false);
867 setAttributeItem(ARMBuildAttrs::Advanced_SIMD_arch,
868 ARMBuildAttrs::AllowNeon,
869 /* OverwriteExisting= */ false);
870 break;
871
872 case ARM::FK_NEON_FP16:
873 setAttributeItem(ARMBuildAttrs::FP_arch,
874 ARMBuildAttrs::AllowFPv3A,
875 /* OverwriteExisting= */ false);
876 setAttributeItem(ARMBuildAttrs::Advanced_SIMD_arch,
877 ARMBuildAttrs::AllowNeon,
878 /* OverwriteExisting= */ false);
879 setAttributeItem(ARMBuildAttrs::FP_HP_extension,
880 ARMBuildAttrs::AllowHPFP,
881 /* OverwriteExisting= */ false);
882 break;
883
884 case ARM::FK_NEON_VFPV4:
885 setAttributeItem(ARMBuildAttrs::FP_arch,
886 ARMBuildAttrs::AllowFPv4A,
887 /* OverwriteExisting= */ false);
888 setAttributeItem(ARMBuildAttrs::Advanced_SIMD_arch,
889 ARMBuildAttrs::AllowNeon2,
890 /* OverwriteExisting= */ false);
891 break;
892
893 case ARM::FK_NEON_FP_ARMV8:
894 case ARM::FK_CRYPTO_NEON_FP_ARMV8:
895 setAttributeItem(ARMBuildAttrs::FP_arch,
896 ARMBuildAttrs::AllowFPARMv8A,
897 /* OverwriteExisting= */ false);
898 // 'Advanced_SIMD_arch' must be emitted not here, but within
899 // ARMAsmPrinter::emitAttributes(), depending on hasV8Ops() and hasV8_1a()
900 break;
901
902 case ARM::FK_SOFTVFP:
903 case ARM::FK_NONE:
904 break;
905
906 default:
907 report_fatal_error("Unknown FPU: " + Twine(FPU));
908 break;
909 }
910 }
calculateContentSize() const911 size_t ARMTargetELFStreamer::calculateContentSize() const {
912 size_t Result = 0;
913 for (size_t i = 0; i < Contents.size(); ++i) {
914 AttributeItem item = Contents[i];
915 switch (item.Type) {
916 case AttributeItem::HiddenAttribute:
917 break;
918 case AttributeItem::NumericAttribute:
919 Result += getULEB128Size(item.Tag);
920 Result += getULEB128Size(item.IntValue);
921 break;
922 case AttributeItem::TextAttribute:
923 Result += getULEB128Size(item.Tag);
924 Result += item.StringValue.size() + 1; // string + '\0'
925 break;
926 case AttributeItem::NumericAndTextAttributes:
927 Result += getULEB128Size(item.Tag);
928 Result += getULEB128Size(item.IntValue);
929 Result += item.StringValue.size() + 1; // string + '\0';
930 break;
931 }
932 }
933 return Result;
934 }
finishAttributeSection()935 void ARMTargetELFStreamer::finishAttributeSection() {
936 // <format-version>
937 // [ <section-length> "vendor-name"
938 // [ <file-tag> <size> <attribute>*
939 // | <section-tag> <size> <section-number>* 0 <attribute>*
940 // | <symbol-tag> <size> <symbol-number>* 0 <attribute>*
941 // ]+
942 // ]*
943
944 if (FPU != ARM::FK_INVALID)
945 emitFPUDefaultAttributes();
946
947 if (Arch != ARM::AK_INVALID)
948 emitArchDefaultAttributes();
949
950 if (Contents.empty())
951 return;
952
953 std::sort(Contents.begin(), Contents.end(), AttributeItem::LessTag);
954
955 ARMELFStreamer &Streamer = getStreamer();
956
957 // Switch to .ARM.attributes section
958 if (AttributeSection) {
959 Streamer.SwitchSection(AttributeSection);
960 } else {
961 AttributeSection = Streamer.getContext().getELFSection(
962 ".ARM.attributes", ELF::SHT_ARM_ATTRIBUTES, 0);
963 Streamer.SwitchSection(AttributeSection);
964
965 // Format version
966 Streamer.EmitIntValue(0x41, 1);
967 }
968
969 // Vendor size + Vendor name + '\0'
970 const size_t VendorHeaderSize = 4 + CurrentVendor.size() + 1;
971
972 // Tag + Tag Size
973 const size_t TagHeaderSize = 1 + 4;
974
975 const size_t ContentsSize = calculateContentSize();
976
977 Streamer.EmitIntValue(VendorHeaderSize + TagHeaderSize + ContentsSize, 4);
978 Streamer.EmitBytes(CurrentVendor);
979 Streamer.EmitIntValue(0, 1); // '\0'
980
981 Streamer.EmitIntValue(ARMBuildAttrs::File, 1);
982 Streamer.EmitIntValue(TagHeaderSize + ContentsSize, 4);
983
984 // Size should have been accounted for already, now
985 // emit each field as its type (ULEB or String)
986 for (size_t i = 0; i < Contents.size(); ++i) {
987 AttributeItem item = Contents[i];
988 Streamer.EmitULEB128IntValue(item.Tag);
989 switch (item.Type) {
990 default: llvm_unreachable("Invalid attribute type");
991 case AttributeItem::NumericAttribute:
992 Streamer.EmitULEB128IntValue(item.IntValue);
993 break;
994 case AttributeItem::TextAttribute:
995 Streamer.EmitBytes(item.StringValue);
996 Streamer.EmitIntValue(0, 1); // '\0'
997 break;
998 case AttributeItem::NumericAndTextAttributes:
999 Streamer.EmitULEB128IntValue(item.IntValue);
1000 Streamer.EmitBytes(item.StringValue);
1001 Streamer.EmitIntValue(0, 1); // '\0'
1002 break;
1003 }
1004 }
1005
1006 Contents.clear();
1007 FPU = ARM::FK_INVALID;
1008 }
1009
emitLabel(MCSymbol * Symbol)1010 void ARMTargetELFStreamer::emitLabel(MCSymbol *Symbol) {
1011 ARMELFStreamer &Streamer = getStreamer();
1012 if (!Streamer.IsThumb)
1013 return;
1014
1015 Streamer.getAssembler().registerSymbol(*Symbol);
1016 unsigned Type = cast<MCSymbolELF>(Symbol)->getType();
1017 if (Type == ELF::STT_FUNC || Type == ELF::STT_GNU_IFUNC)
1018 Streamer.EmitThumbFunc(Symbol);
1019 }
1020
1021 void
AnnotateTLSDescriptorSequence(const MCSymbolRefExpr * S)1022 ARMTargetELFStreamer::AnnotateTLSDescriptorSequence(const MCSymbolRefExpr *S) {
1023 getStreamer().EmitFixup(S, FK_Data_4);
1024 }
1025
emitThumbSet(MCSymbol * Symbol,const MCExpr * Value)1026 void ARMTargetELFStreamer::emitThumbSet(MCSymbol *Symbol, const MCExpr *Value) {
1027 if (const MCSymbolRefExpr *SRE = dyn_cast<MCSymbolRefExpr>(Value)) {
1028 const MCSymbol &Sym = SRE->getSymbol();
1029 if (!Sym.isDefined()) {
1030 getStreamer().EmitAssignment(Symbol, Value);
1031 return;
1032 }
1033 }
1034
1035 getStreamer().EmitThumbFunc(Symbol);
1036 getStreamer().EmitAssignment(Symbol, Value);
1037 }
1038
emitInst(uint32_t Inst,char Suffix)1039 void ARMTargetELFStreamer::emitInst(uint32_t Inst, char Suffix) {
1040 getStreamer().emitInst(Inst, Suffix);
1041 }
1042
FinishImpl()1043 void ARMELFStreamer::FinishImpl() {
1044 MCTargetStreamer &TS = *getTargetStreamer();
1045 ARMTargetStreamer &ATS = static_cast<ARMTargetStreamer &>(TS);
1046 ATS.finishAttributeSection();
1047
1048 MCELFStreamer::FinishImpl();
1049 }
1050
SwitchToEHSection(const char * Prefix,unsigned Type,unsigned Flags,SectionKind Kind,const MCSymbol & Fn)1051 inline void ARMELFStreamer::SwitchToEHSection(const char *Prefix,
1052 unsigned Type,
1053 unsigned Flags,
1054 SectionKind Kind,
1055 const MCSymbol &Fn) {
1056 const MCSectionELF &FnSection =
1057 static_cast<const MCSectionELF &>(Fn.getSection());
1058
1059 // Create the name for new section
1060 StringRef FnSecName(FnSection.getSectionName());
1061 SmallString<128> EHSecName(Prefix);
1062 if (FnSecName != ".text") {
1063 EHSecName += FnSecName;
1064 }
1065
1066 // Get .ARM.extab or .ARM.exidx section
1067 const MCSymbolELF *Group = FnSection.getGroup();
1068 if (Group)
1069 Flags |= ELF::SHF_GROUP;
1070 MCSectionELF *EHSection =
1071 getContext().getELFSection(EHSecName, Type, Flags, 0, Group,
1072 FnSection.getUniqueID(), nullptr, &FnSection);
1073
1074 assert(EHSection && "Failed to get the required EH section");
1075
1076 // Switch to .ARM.extab or .ARM.exidx section
1077 SwitchSection(EHSection);
1078 EmitCodeAlignment(4);
1079 }
1080
SwitchToExTabSection(const MCSymbol & FnStart)1081 inline void ARMELFStreamer::SwitchToExTabSection(const MCSymbol &FnStart) {
1082 SwitchToEHSection(".ARM.extab", ELF::SHT_PROGBITS, ELF::SHF_ALLOC,
1083 SectionKind::getData(), FnStart);
1084 }
1085
SwitchToExIdxSection(const MCSymbol & FnStart)1086 inline void ARMELFStreamer::SwitchToExIdxSection(const MCSymbol &FnStart) {
1087 SwitchToEHSection(".ARM.exidx", ELF::SHT_ARM_EXIDX,
1088 ELF::SHF_ALLOC | ELF::SHF_LINK_ORDER,
1089 SectionKind::getData(), FnStart);
1090 }
EmitFixup(const MCExpr * Expr,MCFixupKind Kind)1091 void ARMELFStreamer::EmitFixup(const MCExpr *Expr, MCFixupKind Kind) {
1092 MCDataFragment *Frag = getOrCreateDataFragment();
1093 Frag->getFixups().push_back(MCFixup::create(Frag->getContents().size(), Expr,
1094 Kind));
1095 }
1096
Reset()1097 void ARMELFStreamer::Reset() {
1098 ExTab = nullptr;
1099 FnStart = nullptr;
1100 Personality = nullptr;
1101 PersonalityIndex = ARM::EHABI::NUM_PERSONALITY_INDEX;
1102 FPReg = ARM::SP;
1103 FPOffset = 0;
1104 SPOffset = 0;
1105 PendingOffset = 0;
1106 UsedFP = false;
1107 CantUnwind = false;
1108
1109 Opcodes.clear();
1110 UnwindOpAsm.Reset();
1111 }
1112
emitFnStart()1113 void ARMELFStreamer::emitFnStart() {
1114 assert(FnStart == nullptr);
1115 FnStart = getContext().createTempSymbol();
1116 EmitLabel(FnStart);
1117 }
1118
emitFnEnd()1119 void ARMELFStreamer::emitFnEnd() {
1120 assert(FnStart && ".fnstart must precedes .fnend");
1121
1122 // Emit unwind opcodes if there is no .handlerdata directive
1123 if (!ExTab && !CantUnwind)
1124 FlushUnwindOpcodes(true);
1125
1126 // Emit the exception index table entry
1127 SwitchToExIdxSection(*FnStart);
1128
1129 if (PersonalityIndex < ARM::EHABI::NUM_PERSONALITY_INDEX)
1130 EmitPersonalityFixup(GetAEABIUnwindPersonalityName(PersonalityIndex));
1131
1132 const MCSymbolRefExpr *FnStartRef =
1133 MCSymbolRefExpr::create(FnStart,
1134 MCSymbolRefExpr::VK_ARM_PREL31,
1135 getContext());
1136
1137 EmitValue(FnStartRef, 4);
1138
1139 if (CantUnwind) {
1140 EmitIntValue(ARM::EHABI::EXIDX_CANTUNWIND, 4);
1141 } else if (ExTab) {
1142 // Emit a reference to the unwind opcodes in the ".ARM.extab" section.
1143 const MCSymbolRefExpr *ExTabEntryRef =
1144 MCSymbolRefExpr::create(ExTab,
1145 MCSymbolRefExpr::VK_ARM_PREL31,
1146 getContext());
1147 EmitValue(ExTabEntryRef, 4);
1148 } else {
1149 // For the __aeabi_unwind_cpp_pr0, we have to emit the unwind opcodes in
1150 // the second word of exception index table entry. The size of the unwind
1151 // opcodes should always be 4 bytes.
1152 assert(PersonalityIndex == ARM::EHABI::AEABI_UNWIND_CPP_PR0 &&
1153 "Compact model must use __aeabi_unwind_cpp_pr0 as personality");
1154 assert(Opcodes.size() == 4u &&
1155 "Unwind opcode size for __aeabi_unwind_cpp_pr0 must be equal to 4");
1156 uint64_t Intval = Opcodes[0] |
1157 Opcodes[1] << 8 |
1158 Opcodes[2] << 16 |
1159 Opcodes[3] << 24;
1160 EmitIntValue(Intval, Opcodes.size());
1161 }
1162
1163 // Switch to the section containing FnStart
1164 SwitchSection(&FnStart->getSection());
1165
1166 // Clean exception handling frame information
1167 Reset();
1168 }
1169
emitCantUnwind()1170 void ARMELFStreamer::emitCantUnwind() { CantUnwind = true; }
1171
1172 // Add the R_ARM_NONE fixup at the same position
EmitPersonalityFixup(StringRef Name)1173 void ARMELFStreamer::EmitPersonalityFixup(StringRef Name) {
1174 const MCSymbol *PersonalitySym = getContext().getOrCreateSymbol(Name);
1175
1176 const MCSymbolRefExpr *PersonalityRef = MCSymbolRefExpr::create(
1177 PersonalitySym, MCSymbolRefExpr::VK_ARM_NONE, getContext());
1178
1179 visitUsedExpr(*PersonalityRef);
1180 MCDataFragment *DF = getOrCreateDataFragment();
1181 DF->getFixups().push_back(MCFixup::create(DF->getContents().size(),
1182 PersonalityRef,
1183 MCFixup::getKindForSize(4, false)));
1184 }
1185
FlushPendingOffset()1186 void ARMELFStreamer::FlushPendingOffset() {
1187 if (PendingOffset != 0) {
1188 UnwindOpAsm.EmitSPOffset(-PendingOffset);
1189 PendingOffset = 0;
1190 }
1191 }
1192
FlushUnwindOpcodes(bool NoHandlerData)1193 void ARMELFStreamer::FlushUnwindOpcodes(bool NoHandlerData) {
1194 // Emit the unwind opcode to restore $sp.
1195 if (UsedFP) {
1196 const MCRegisterInfo *MRI = getContext().getRegisterInfo();
1197 int64_t LastRegSaveSPOffset = SPOffset - PendingOffset;
1198 UnwindOpAsm.EmitSPOffset(LastRegSaveSPOffset - FPOffset);
1199 UnwindOpAsm.EmitSetSP(MRI->getEncodingValue(FPReg));
1200 } else {
1201 FlushPendingOffset();
1202 }
1203
1204 // Finalize the unwind opcode sequence
1205 UnwindOpAsm.Finalize(PersonalityIndex, Opcodes);
1206
1207 // For compact model 0, we have to emit the unwind opcodes in the .ARM.exidx
1208 // section. Thus, we don't have to create an entry in the .ARM.extab
1209 // section.
1210 if (NoHandlerData && PersonalityIndex == ARM::EHABI::AEABI_UNWIND_CPP_PR0)
1211 return;
1212
1213 // Switch to .ARM.extab section.
1214 SwitchToExTabSection(*FnStart);
1215
1216 // Create .ARM.extab label for offset in .ARM.exidx
1217 assert(!ExTab);
1218 ExTab = getContext().createTempSymbol();
1219 EmitLabel(ExTab);
1220
1221 // Emit personality
1222 if (Personality) {
1223 const MCSymbolRefExpr *PersonalityRef =
1224 MCSymbolRefExpr::create(Personality,
1225 MCSymbolRefExpr::VK_ARM_PREL31,
1226 getContext());
1227
1228 EmitValue(PersonalityRef, 4);
1229 }
1230
1231 // Emit unwind opcodes
1232 assert((Opcodes.size() % 4) == 0 &&
1233 "Unwind opcode size for __aeabi_cpp_unwind_pr0 must be multiple of 4");
1234 for (unsigned I = 0; I != Opcodes.size(); I += 4) {
1235 uint64_t Intval = Opcodes[I] |
1236 Opcodes[I + 1] << 8 |
1237 Opcodes[I + 2] << 16 |
1238 Opcodes[I + 3] << 24;
1239 EmitIntValue(Intval, 4);
1240 }
1241
1242 // According to ARM EHABI section 9.2, if the __aeabi_unwind_cpp_pr1() or
1243 // __aeabi_unwind_cpp_pr2() is used, then the handler data must be emitted
1244 // after the unwind opcodes. The handler data consists of several 32-bit
1245 // words, and should be terminated by zero.
1246 //
1247 // In case that the .handlerdata directive is not specified by the
1248 // programmer, we should emit zero to terminate the handler data.
1249 if (NoHandlerData && !Personality)
1250 EmitIntValue(0, 4);
1251 }
1252
emitHandlerData()1253 void ARMELFStreamer::emitHandlerData() { FlushUnwindOpcodes(false); }
1254
emitPersonality(const MCSymbol * Per)1255 void ARMELFStreamer::emitPersonality(const MCSymbol *Per) {
1256 Personality = Per;
1257 UnwindOpAsm.setPersonality(Per);
1258 }
1259
emitPersonalityIndex(unsigned Index)1260 void ARMELFStreamer::emitPersonalityIndex(unsigned Index) {
1261 assert(Index < ARM::EHABI::NUM_PERSONALITY_INDEX && "invalid index");
1262 PersonalityIndex = Index;
1263 }
1264
emitSetFP(unsigned NewFPReg,unsigned NewSPReg,int64_t Offset)1265 void ARMELFStreamer::emitSetFP(unsigned NewFPReg, unsigned NewSPReg,
1266 int64_t Offset) {
1267 assert((NewSPReg == ARM::SP || NewSPReg == FPReg) &&
1268 "the operand of .setfp directive should be either $sp or $fp");
1269
1270 UsedFP = true;
1271 FPReg = NewFPReg;
1272
1273 if (NewSPReg == ARM::SP)
1274 FPOffset = SPOffset + Offset;
1275 else
1276 FPOffset += Offset;
1277 }
1278
emitMovSP(unsigned Reg,int64_t Offset)1279 void ARMELFStreamer::emitMovSP(unsigned Reg, int64_t Offset) {
1280 assert((Reg != ARM::SP && Reg != ARM::PC) &&
1281 "the operand of .movsp cannot be either sp or pc");
1282 assert(FPReg == ARM::SP && "current FP must be SP");
1283
1284 FlushPendingOffset();
1285
1286 FPReg = Reg;
1287 FPOffset = SPOffset + Offset;
1288
1289 const MCRegisterInfo *MRI = getContext().getRegisterInfo();
1290 UnwindOpAsm.EmitSetSP(MRI->getEncodingValue(FPReg));
1291 }
1292
emitPad(int64_t Offset)1293 void ARMELFStreamer::emitPad(int64_t Offset) {
1294 // Track the change of the $sp offset
1295 SPOffset -= Offset;
1296
1297 // To squash multiple .pad directives, we should delay the unwind opcode
1298 // until the .save, .vsave, .handlerdata, or .fnend directives.
1299 PendingOffset -= Offset;
1300 }
1301
emitRegSave(const SmallVectorImpl<unsigned> & RegList,bool IsVector)1302 void ARMELFStreamer::emitRegSave(const SmallVectorImpl<unsigned> &RegList,
1303 bool IsVector) {
1304 // Collect the registers in the register list
1305 unsigned Count = 0;
1306 uint32_t Mask = 0;
1307 const MCRegisterInfo *MRI = getContext().getRegisterInfo();
1308 for (size_t i = 0; i < RegList.size(); ++i) {
1309 unsigned Reg = MRI->getEncodingValue(RegList[i]);
1310 assert(Reg < (IsVector ? 32U : 16U) && "Register out of range");
1311 unsigned Bit = (1u << Reg);
1312 if ((Mask & Bit) == 0) {
1313 Mask |= Bit;
1314 ++Count;
1315 }
1316 }
1317
1318 // Track the change the $sp offset: For the .save directive, the
1319 // corresponding push instruction will decrease the $sp by (4 * Count).
1320 // For the .vsave directive, the corresponding vpush instruction will
1321 // decrease $sp by (8 * Count).
1322 SPOffset -= Count * (IsVector ? 8 : 4);
1323
1324 // Emit the opcode
1325 FlushPendingOffset();
1326 if (IsVector)
1327 UnwindOpAsm.EmitVFPRegSave(Mask);
1328 else
1329 UnwindOpAsm.EmitRegSave(Mask);
1330 }
1331
emitUnwindRaw(int64_t Offset,const SmallVectorImpl<uint8_t> & Opcodes)1332 void ARMELFStreamer::emitUnwindRaw(int64_t Offset,
1333 const SmallVectorImpl<uint8_t> &Opcodes) {
1334 FlushPendingOffset();
1335 SPOffset = SPOffset - Offset;
1336 UnwindOpAsm.EmitRaw(Opcodes);
1337 }
1338
1339 namespace llvm {
1340
createARMTargetAsmStreamer(MCStreamer & S,formatted_raw_ostream & OS,MCInstPrinter * InstPrint,bool isVerboseAsm)1341 MCTargetStreamer *createARMTargetAsmStreamer(MCStreamer &S,
1342 formatted_raw_ostream &OS,
1343 MCInstPrinter *InstPrint,
1344 bool isVerboseAsm) {
1345 return new ARMTargetAsmStreamer(S, OS, *InstPrint, isVerboseAsm);
1346 }
1347
createARMNullTargetStreamer(MCStreamer & S)1348 MCTargetStreamer *createARMNullTargetStreamer(MCStreamer &S) {
1349 return new ARMTargetStreamer(S);
1350 }
1351
createARMObjectTargetStreamer(MCStreamer & S,const MCSubtargetInfo & STI)1352 MCTargetStreamer *createARMObjectTargetStreamer(MCStreamer &S,
1353 const MCSubtargetInfo &STI) {
1354 const Triple &TT = STI.getTargetTriple();
1355 if (TT.isOSBinFormatELF())
1356 return new ARMTargetELFStreamer(S);
1357 return new ARMTargetStreamer(S);
1358 }
1359
createARMELFStreamer(MCContext & Context,MCAsmBackend & TAB,raw_pwrite_stream & OS,MCCodeEmitter * Emitter,bool RelaxAll,bool IsThumb)1360 MCELFStreamer *createARMELFStreamer(MCContext &Context, MCAsmBackend &TAB,
1361 raw_pwrite_stream &OS,
1362 MCCodeEmitter *Emitter, bool RelaxAll,
1363 bool IsThumb) {
1364 ARMELFStreamer *S = new ARMELFStreamer(Context, TAB, OS, Emitter, IsThumb);
1365 // FIXME: This should eventually end up somewhere else where more
1366 // intelligent flag decisions can be made. For now we are just maintaining
1367 // the status quo for ARM and setting EF_ARM_EABI_VER5 as the default.
1368 S->getAssembler().setELFHeaderEFlags(ELF::EF_ARM_EABI_VER5);
1369
1370 if (RelaxAll)
1371 S->getAssembler().setRelaxAll(true);
1372 return S;
1373 }
1374
1375 }
1376
1377
1378