llvm.org GIT mirror llvm / release_25 lib / Target / X86 / X86TargetAsmInfo.cpp
release_25

Tree @release_25 (Download .tar.gz)

X86TargetAsmInfo.cpp @release_25raw · history · blame

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
//===-- X86TargetAsmInfo.cpp - X86 asm properties ---------------*- C++ -*-===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file contains the declarations of the X86TargetAsmInfo properties.
//
//===----------------------------------------------------------------------===//

#include "X86TargetAsmInfo.h"
#include "X86TargetMachine.h"
#include "X86Subtarget.h"
#include "llvm/DerivedTypes.h"
#include "llvm/InlineAsm.h"
#include "llvm/Instructions.h"
#include "llvm/Intrinsics.h"
#include "llvm/Module.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/Support/Dwarf.h"

using namespace llvm;
using namespace llvm::dwarf;

const char *const llvm::x86_asm_table[] = {
  "{si}", "S",
  "{di}", "D",
  "{ax}", "a",
  "{cx}", "c",
  "{memory}", "memory",
  "{flags}", "",
  "{dirflag}", "",
  "{fpsr}", "",
  "{cc}", "cc",
  0,0};

X86DarwinTargetAsmInfo::X86DarwinTargetAsmInfo(const X86TargetMachine &TM):
  X86TargetAsmInfo<DarwinTargetAsmInfo>(TM) {
  const X86Subtarget* Subtarget = &TM.getSubtarget<X86Subtarget>();
  bool is64Bit = Subtarget->is64Bit();

  AlignmentIsInBytes = false;
  TextAlignFillValue = 0x90;
  GlobalPrefix = "_";
  if (!is64Bit)
    Data64bitsDirective = 0;       // we can't emit a 64-bit unit
  ZeroDirective = "\t.space\t";  // ".space N" emits N zeros.
  PrivateGlobalPrefix = "L";     // Marker for constant pool idxs
  LessPrivateGlobalPrefix = "l";  // Marker for some ObjC metadata
  BSSSection = 0;                       // no BSS section.
  ZeroFillDirective = "\t.zerofill\t";  // Uses .zerofill
  if (TM.getRelocationModel() != Reloc::Static)
    ConstantPoolSection = "\t.const_data";
  else
    ConstantPoolSection = "\t.const\n";
  JumpTableDataSection = "\t.const\n";
  CStringSection = "\t.cstring";
  // FIXME: Why don't always use this section?
  if (is64Bit) {
    SixteenByteConstantSection = getUnnamedSection("\t.literal16\n",
                                                   SectionFlags::Mergeable);
  }
  LCOMMDirective = "\t.lcomm\t";
  SwitchToSectionDirective = "\t.section ";
  StringConstantPrefix = "\1LC";
  // Leopard and above support aligned common symbols.
  COMMDirectiveTakesAlignment = (Subtarget->getDarwinVers() >= 9);
  HasDotTypeDotSizeDirective = false;
  HasSingleParameterDotFile = false;
  NonLocalEHFrameLabel = true;
  if (TM.getRelocationModel() == Reloc::Static) {
    StaticCtorsSection = ".constructor";
    StaticDtorsSection = ".destructor";
  } else {
    StaticCtorsSection = ".mod_init_func";
    StaticDtorsSection = ".mod_term_func";
  }
  if (is64Bit) {
    PersonalityPrefix = "";
    PersonalitySuffix = "+4@GOTPCREL";
  } else {
    PersonalityPrefix = "L";
    PersonalitySuffix = "$non_lazy_ptr";
  }
  NeedsIndirectEncoding = true;
  InlineAsmStart = "## InlineAsm Start";
  InlineAsmEnd = "## InlineAsm End";
  CommentString = "##";
  SetDirective = "\t.set";
  PCSymbol = ".";
  UsedDirective = "\t.no_dead_strip\t";
  WeakDefDirective = "\t.weak_definition ";
  WeakRefDirective = "\t.weak_reference ";
  HiddenDirective = "\t.private_extern ";
  ProtectedDirective = "\t.globl\t";

  // In non-PIC modes, emit a special label before jump tables so that the
  // linker can perform more accurate dead code stripping.
  if (TM.getRelocationModel() != Reloc::PIC_) {
    // Emit a local label that is preserved until the linker runs.
    JumpTableSpecialLabelPrefix = "l";
  }

  SupportsDebugInformation = true;
  NeedsSet = true;
  DwarfAbbrevSection = ".section __DWARF,__debug_abbrev,regular,debug";
  DwarfInfoSection = ".section __DWARF,__debug_info,regular,debug";
  DwarfLineSection = ".section __DWARF,__debug_line,regular,debug";
  DwarfFrameSection = ".section __DWARF,__debug_frame,regular,debug";
  DwarfPubNamesSection = ".section __DWARF,__debug_pubnames,regular,debug";
  DwarfPubTypesSection = ".section __DWARF,__debug_pubtypes,regular,debug";
  DwarfStrSection = ".section __DWARF,__debug_str,regular,debug";
  DwarfLocSection = ".section __DWARF,__debug_loc,regular,debug";
  DwarfARangesSection = ".section __DWARF,__debug_aranges,regular,debug";
  DwarfRangesSection = ".section __DWARF,__debug_ranges,regular,debug";
  DwarfMacInfoSection = ".section __DWARF,__debug_macinfo,regular,debug";

  // Exceptions handling
  SupportsExceptionHandling = true;
  GlobalEHDirective = "\t.globl\t";
  SupportsWeakOmittedEHFrame = false;
  AbsoluteEHSectionOffsets = false;
  DwarfEHFrameSection =
  ".section __TEXT,__eh_frame,coalesced,no_toc+strip_static_syms+live_support";
  DwarfExceptionSection = ".section __DATA,__gcc_except_tab";
}

unsigned
X86DarwinTargetAsmInfo::PreferredEHDataFormat(DwarfEncoding::Target Reason,
                                              bool Global) const {
  if (Reason == DwarfEncoding::Functions && Global)
    return (DW_EH_PE_pcrel | DW_EH_PE_indirect | DW_EH_PE_sdata4);
  else if (Reason == DwarfEncoding::CodeLabels || !Global)
    return DW_EH_PE_pcrel;
  else
    return DW_EH_PE_absptr;
}

const char *
X86DarwinTargetAsmInfo::getEHGlobalPrefix() const
{
  const X86Subtarget* Subtarget = &TM.getSubtarget<X86Subtarget>();
  if (Subtarget->getDarwinVers() > 9)
    return PrivateGlobalPrefix;
  else
    return "";
}

X86ELFTargetAsmInfo::X86ELFTargetAsmInfo(const X86TargetMachine &TM):
  X86TargetAsmInfo<ELFTargetAsmInfo>(TM) {

  CStringSection = ".rodata.str";
  PrivateGlobalPrefix = ".L";
  WeakRefDirective = "\t.weak\t";
  SetDirective = "\t.set\t";
  PCSymbol = ".";

  // Set up DWARF directives
  HasLEB128 = true;  // Target asm supports leb128 directives (little-endian)

  // Debug Information
  AbsoluteDebugSectionOffsets = true;
  SupportsDebugInformation = true;
  DwarfAbbrevSection =  "\t.section\t.debug_abbrev,\"\",@progbits";
  DwarfInfoSection =    "\t.section\t.debug_info,\"\",@progbits";
  DwarfLineSection =    "\t.section\t.debug_line,\"\",@progbits";
  DwarfFrameSection =   "\t.section\t.debug_frame,\"\",@progbits";
  DwarfPubNamesSection ="\t.section\t.debug_pubnames,\"\",@progbits";
  DwarfPubTypesSection ="\t.section\t.debug_pubtypes,\"\",@progbits";
  DwarfStrSection =     "\t.section\t.debug_str,\"\",@progbits";
  DwarfLocSection =     "\t.section\t.debug_loc,\"\",@progbits";
  DwarfARangesSection = "\t.section\t.debug_aranges,\"\",@progbits";
  DwarfRangesSection =  "\t.section\t.debug_ranges,\"\",@progbits";
  DwarfMacInfoSection = "\t.section\t.debug_macinfo,\"\",@progbits";

  // Exceptions handling
  SupportsExceptionHandling = true;
  AbsoluteEHSectionOffsets = false;
  DwarfEHFrameSection = "\t.section\t.eh_frame,\"aw\",@progbits";
  DwarfExceptionSection = "\t.section\t.gcc_except_table,\"a\",@progbits";

  // On Linux we must declare when we can use a non-executable stack.
  if (TM.getSubtarget<X86Subtarget>().isLinux())
    NonexecutableStackDirective = "\t.section\t.note.GNU-stack,\"\",@progbits";
}

unsigned
X86ELFTargetAsmInfo::PreferredEHDataFormat(DwarfEncoding::Target Reason,
                                           bool Global) const {
  CodeModel::Model CM = TM.getCodeModel();
  bool is64Bit = TM.getSubtarget<X86Subtarget>().is64Bit();

  if (TM.getRelocationModel() == Reloc::PIC_) {
    unsigned Format = 0;

    if (!is64Bit)
      // 32 bit targets always encode pointers as 4 bytes
      Format = DW_EH_PE_sdata4;
    else {
      // 64 bit targets encode pointers in 4 bytes iff:
      // - code model is small OR
      // - code model is medium and we're emitting externally visible symbols
      //   or any code symbols
      if (CM == CodeModel::Small ||
          (CM == CodeModel::Medium && (Global ||
                                       Reason != DwarfEncoding::Data)))
        Format = DW_EH_PE_sdata4;
      else
        Format = DW_EH_PE_sdata8;
    }

    if (Global)
      Format |= DW_EH_PE_indirect;

    return (Format | DW_EH_PE_pcrel);
  } else {
    if (is64Bit &&
        (CM == CodeModel::Small ||
         (CM == CodeModel::Medium && Reason != DwarfEncoding::Data)))
      return DW_EH_PE_udata4;
    else
      return DW_EH_PE_absptr;
  }
}

X86COFFTargetAsmInfo::X86COFFTargetAsmInfo(const X86TargetMachine &TM):
  X86GenericTargetAsmInfo(TM) {

  GlobalPrefix = "_";
  LCOMMDirective = "\t.lcomm\t";
  COMMDirectiveTakesAlignment = false;
  HasDotTypeDotSizeDirective = false;
  HasSingleParameterDotFile = false;
  StaticCtorsSection = "\t.section .ctors,\"aw\"";
  StaticDtorsSection = "\t.section .dtors,\"aw\"";
  HiddenDirective = NULL;
  PrivateGlobalPrefix = "L";  // Prefix for private global symbols
  WeakRefDirective = "\t.weak\t";
  SetDirective = "\t.set\t";

  // Set up DWARF directives
  HasLEB128 = true;  // Target asm supports leb128 directives (little-endian)
  AbsoluteDebugSectionOffsets = true;
  AbsoluteEHSectionOffsets = false;
  SupportsDebugInformation = true;
  DwarfSectionOffsetDirective = "\t.secrel32\t";
  DwarfAbbrevSection =  "\t.section\t.debug_abbrev,\"dr\"";
  DwarfInfoSection =    "\t.section\t.debug_info,\"dr\"";
  DwarfLineSection =    "\t.section\t.debug_line,\"dr\"";
  DwarfFrameSection =   "\t.section\t.debug_frame,\"dr\"";
  DwarfPubNamesSection ="\t.section\t.debug_pubnames,\"dr\"";
  DwarfPubTypesSection ="\t.section\t.debug_pubtypes,\"dr\"";
  DwarfStrSection =     "\t.section\t.debug_str,\"dr\"";
  DwarfLocSection =     "\t.section\t.debug_loc,\"dr\"";
  DwarfARangesSection = "\t.section\t.debug_aranges,\"dr\"";
  DwarfRangesSection =  "\t.section\t.debug_ranges,\"dr\"";
  DwarfMacInfoSection = "\t.section\t.debug_macinfo,\"dr\"";
}

unsigned
X86COFFTargetAsmInfo::PreferredEHDataFormat(DwarfEncoding::Target Reason,
                                            bool Global) const {
  CodeModel::Model CM = TM.getCodeModel();
  bool is64Bit = TM.getSubtarget<X86Subtarget>().is64Bit();

  if (TM.getRelocationModel() == Reloc::PIC_) {
    unsigned Format = 0;

    if (!is64Bit)
      // 32 bit targets always encode pointers as 4 bytes
      Format = DW_EH_PE_sdata4;
    else {
      // 64 bit targets encode pointers in 4 bytes iff:
      // - code model is small OR
      // - code model is medium and we're emitting externally visible symbols
      //   or any code symbols
      if (CM == CodeModel::Small ||
          (CM == CodeModel::Medium && (Global ||
                                       Reason != DwarfEncoding::Data)))
        Format = DW_EH_PE_sdata4;
      else
        Format = DW_EH_PE_sdata8;
    }

    if (Global)
      Format |= DW_EH_PE_indirect;

    return (Format | DW_EH_PE_pcrel);
  } else {
    if (is64Bit &&
        (CM == CodeModel::Small ||
         (CM == CodeModel::Medium && Reason != DwarfEncoding::Data)))
      return DW_EH_PE_udata4;
    else
      return DW_EH_PE_absptr;
  }
}

std::string
X86COFFTargetAsmInfo::UniqueSectionForGlobal(const GlobalValue* GV,
                                             SectionKind::Kind kind) const {
  switch (kind) {
   case SectionKind::Text:
    return ".text$linkonce" + GV->getName();
   case SectionKind::Data:
   case SectionKind::BSS:
   case SectionKind::ThreadData:
   case SectionKind::ThreadBSS:
    return ".data$linkonce" + GV->getName();
   case SectionKind::ROData:
   case SectionKind::RODataMergeConst:
   case SectionKind::RODataMergeStr:
    return ".rdata$linkonce" + GV->getName();
   default:
    assert(0 && "Unknown section kind");
  }
  return NULL;
}

std::string X86COFFTargetAsmInfo::printSectionFlags(unsigned flags) const {
  std::string Flags = ",\"";

  if (flags & SectionFlags::Code)
    Flags += 'x';
  if (flags & SectionFlags::Writeable)
    Flags += 'w';

  Flags += "\"";

  return Flags;
}

X86WinTargetAsmInfo::X86WinTargetAsmInfo(const X86TargetMachine &TM):
  X86GenericTargetAsmInfo(TM) {
  GlobalPrefix = "_";
  CommentString = ";";

  PrivateGlobalPrefix = "$";
  AlignDirective = "\talign\t";
  ZeroDirective = "\tdb\t";
  ZeroDirectiveSuffix = " dup(0)";
  AsciiDirective = "\tdb\t";
  AscizDirective = 0;
  Data8bitsDirective = "\tdb\t";
  Data16bitsDirective = "\tdw\t";
  Data32bitsDirective = "\tdd\t";
  Data64bitsDirective = "\tdq\t";
  HasDotTypeDotSizeDirective = false;
  HasSingleParameterDotFile = false;

  TextSection = getUnnamedSection("_text", SectionFlags::Code);
  DataSection = getUnnamedSection("_data", SectionFlags::Writeable);

  JumpTableDataSection = NULL;
  SwitchToSectionDirective = "";
  TextSectionStartSuffix = "\tsegment 'CODE'";
  DataSectionStartSuffix = "\tsegment 'DATA'";
  SectionEndDirectiveSuffix = "\tends\n";
}

template <class BaseTAI>
bool X86TargetAsmInfo<BaseTAI>::LowerToBSwap(CallInst *CI) const {
  // FIXME: this should verify that we are targetting a 486 or better.  If not,
  // we will turn this bswap into something that will be lowered to logical ops
  // instead of emitting the bswap asm.  For now, we don't support 486 or lower
  // so don't worry about this.

  // Verify this is a simple bswap.
  if (CI->getNumOperands() != 2 ||
      CI->getType() != CI->getOperand(1)->getType() ||
      !CI->getType()->isInteger())
    return false;

  const IntegerType *Ty = dyn_cast<IntegerType>(CI->getType());
  if (!Ty || Ty->getBitWidth() % 16 != 0)
    return false;

  // Okay, we can do this xform, do so now.
  const Type *Tys[] = { Ty };
  Module *M = CI->getParent()->getParent()->getParent();
  Constant *Int = Intrinsic::getDeclaration(M, Intrinsic::bswap, Tys, 1);

  Value *Op = CI->getOperand(1);
  Op = CallInst::Create(Int, Op, CI->getName(), CI);

  CI->replaceAllUsesWith(Op);
  CI->eraseFromParent();
  return true;
}

template <class BaseTAI>
bool X86TargetAsmInfo<BaseTAI>::ExpandInlineAsm(CallInst *CI) const {
  InlineAsm *IA = cast<InlineAsm>(CI->getCalledValue());
  std::vector<InlineAsm::ConstraintInfo> Constraints = IA->ParseConstraints();

  std::string AsmStr = IA->getAsmString();

  // TODO: should remove alternatives from the asmstring: "foo {a|b}" -> "foo a"
  std::vector<std::string> AsmPieces;
  SplitString(AsmStr, AsmPieces, "\n");  // ; as separator?

  switch (AsmPieces.size()) {
  default: return false;
  case 1:
    AsmStr = AsmPieces[0];
    AsmPieces.clear();
    SplitString(AsmStr, AsmPieces, " \t");  // Split with whitespace.

    // bswap $0
    if (AsmPieces.size() == 2 &&
        AsmPieces[0] == "bswap" && (AsmPieces[1] == "$0" ||
                                    AsmPieces[1] == "${0:q}")) {
      // No need to check constraints, nothing other than the equivalent of
      // "=r,0" would be valid here.
      return LowerToBSwap(CI);
    }
    // rorw $$8, ${0:w}  -->  llvm.bswap.i16
    if (CI->getType() == Type::Int16Ty &&
        AsmPieces.size() == 3 &&
        AsmPieces[0] == "rorw" &&
        AsmPieces[1] == "$$8," &&
        AsmPieces[2] == "${0:w}" &&
        IA->getConstraintString() == "=r,0,~{dirflag},~{fpsr},~{flags},~{cc}") {
      return LowerToBSwap(CI);
    }
    break;
  case 3:
    if (CI->getType() == Type::Int64Ty && Constraints.size() >= 2 &&
        Constraints[0].Codes.size() == 1 && Constraints[0].Codes[0] == "A" &&
        Constraints[1].Codes.size() == 1 && Constraints[1].Codes[0] == "0") {
      // bswap %eax / bswap %edx / xchgl %eax, %edx  -> llvm.bswap.i64
      std::vector<std::string> Words;
      SplitString(AsmPieces[0], Words, " \t");
      if (Words.size() == 2 && Words[0] == "bswap" && Words[1] == "%eax") {
        Words.clear();
        SplitString(AsmPieces[1], Words, " \t");
        if (Words.size() == 2 && Words[0] == "bswap" && Words[1] == "%edx") {
          Words.clear();
          SplitString(AsmPieces[2], Words, " \t,");
          if (Words.size() == 3 && Words[0] == "xchgl" && Words[1] == "%eax" &&
              Words[2] == "%edx") {
            return LowerToBSwap(CI);
          }
        }
      }
    }
    break;
  }
  return false;
}

// Instantiate default implementation.
TEMPLATE_INSTANTIATION(class X86TargetAsmInfo<TargetAsmInfo>);