1 //===-- X86AsmPrinter.cpp - Convert X86 LLVM code to AT&T assembly --------===//
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 a printer that converts from our internal representation
11 // of machine-dependent LLVM code to X86 machine code.
12 //
13 //===----------------------------------------------------------------------===//
14 
15 #include "X86AsmPrinter.h"
16 #include "InstPrinter/X86ATTInstPrinter.h"
17 #include "MCTargetDesc/X86BaseInfo.h"
18 #include "X86InstrInfo.h"
19 #include "X86MachineFunctionInfo.h"
20 #include "llvm/ADT/SmallString.h"
21 #include "llvm/CodeGen/MachineConstantPool.h"
22 #include "llvm/CodeGen/MachineModuleInfoImpls.h"
23 #include "llvm/CodeGen/MachineValueType.h"
24 #include "llvm/CodeGen/TargetLoweringObjectFileImpl.h"
25 #include "llvm/IR/DebugInfo.h"
26 #include "llvm/IR/DerivedTypes.h"
27 #include "llvm/IR/Mangler.h"
28 #include "llvm/IR/Module.h"
29 #include "llvm/IR/Type.h"
30 #include "llvm/MC/MCAsmInfo.h"
31 #include "llvm/MC/MCContext.h"
32 #include "llvm/MC/MCExpr.h"
33 #include "llvm/MC/MCSectionCOFF.h"
34 #include "llvm/MC/MCSectionMachO.h"
35 #include "llvm/MC/MCStreamer.h"
36 #include "llvm/MC/MCSymbol.h"
37 #include "llvm/Support/COFF.h"
38 #include "llvm/Support/Debug.h"
39 #include "llvm/Support/ErrorHandling.h"
40 #include "llvm/Support/TargetRegistry.h"
41 using namespace llvm;
42 
43 //===----------------------------------------------------------------------===//
44 // Primitive Helper Functions.
45 //===----------------------------------------------------------------------===//
46 
47 /// runOnMachineFunction - Emit the function body.
48 ///
runOnMachineFunction(MachineFunction & MF)49 bool X86AsmPrinter::runOnMachineFunction(MachineFunction &MF) {
50   Subtarget = &MF.getSubtarget<X86Subtarget>();
51 
52   SMShadowTracker.startFunction(MF);
53 
54   SetupMachineFunction(MF);
55 
56   if (Subtarget->isTargetCOFF()) {
57     bool Intrn = MF.getFunction()->hasInternalLinkage();
58     OutStreamer->BeginCOFFSymbolDef(CurrentFnSym);
59     OutStreamer->EmitCOFFSymbolStorageClass(Intrn ? COFF::IMAGE_SYM_CLASS_STATIC
60                                             : COFF::IMAGE_SYM_CLASS_EXTERNAL);
61     OutStreamer->EmitCOFFSymbolType(COFF::IMAGE_SYM_DTYPE_FUNCTION
62                                                << COFF::SCT_COMPLEX_TYPE_SHIFT);
63     OutStreamer->EndCOFFSymbolDef();
64   }
65 
66   // Emit the rest of the function body.
67   EmitFunctionBody();
68 
69   // We didn't modify anything.
70   return false;
71 }
72 
73 /// printSymbolOperand - Print a raw symbol reference operand.  This handles
74 /// jump tables, constant pools, global address and external symbols, all of
75 /// which print to a label with various suffixes for relocation types etc.
printSymbolOperand(X86AsmPrinter & P,const MachineOperand & MO,raw_ostream & O)76 static void printSymbolOperand(X86AsmPrinter &P, const MachineOperand &MO,
77                                raw_ostream &O) {
78   switch (MO.getType()) {
79   default: llvm_unreachable("unknown symbol type!");
80   case MachineOperand::MO_ConstantPoolIndex:
81     P.GetCPISymbol(MO.getIndex())->print(O, P.MAI);
82     P.printOffset(MO.getOffset(), O);
83     break;
84   case MachineOperand::MO_GlobalAddress: {
85     const GlobalValue *GV = MO.getGlobal();
86 
87     MCSymbol *GVSym;
88     if (MO.getTargetFlags() == X86II::MO_DARWIN_STUB)
89       GVSym = P.getSymbolWithGlobalValueBase(GV, "$stub");
90     else if (MO.getTargetFlags() == X86II::MO_DARWIN_NONLAZY ||
91              MO.getTargetFlags() == X86II::MO_DARWIN_NONLAZY_PIC_BASE ||
92              MO.getTargetFlags() == X86II::MO_DARWIN_HIDDEN_NONLAZY_PIC_BASE)
93       GVSym = P.getSymbolWithGlobalValueBase(GV, "$non_lazy_ptr");
94     else
95       GVSym = P.getSymbol(GV);
96 
97     // Handle dllimport linkage.
98     if (MO.getTargetFlags() == X86II::MO_DLLIMPORT)
99       GVSym =
100           P.OutContext.getOrCreateSymbol(Twine("__imp_") + GVSym->getName());
101 
102     if (MO.getTargetFlags() == X86II::MO_DARWIN_NONLAZY ||
103         MO.getTargetFlags() == X86II::MO_DARWIN_NONLAZY_PIC_BASE) {
104       MCSymbol *Sym = P.getSymbolWithGlobalValueBase(GV, "$non_lazy_ptr");
105       MachineModuleInfoImpl::StubValueTy &StubSym =
106           P.MMI->getObjFileInfo<MachineModuleInfoMachO>().getGVStubEntry(Sym);
107       if (!StubSym.getPointer())
108         StubSym = MachineModuleInfoImpl::
109           StubValueTy(P.getSymbol(GV), !GV->hasInternalLinkage());
110     } else if (MO.getTargetFlags() == X86II::MO_DARWIN_HIDDEN_NONLAZY_PIC_BASE){
111       MCSymbol *Sym = P.getSymbolWithGlobalValueBase(GV, "$non_lazy_ptr");
112       MachineModuleInfoImpl::StubValueTy &StubSym =
113           P.MMI->getObjFileInfo<MachineModuleInfoMachO>().getHiddenGVStubEntry(
114               Sym);
115       if (!StubSym.getPointer())
116         StubSym = MachineModuleInfoImpl::
117           StubValueTy(P.getSymbol(GV), !GV->hasInternalLinkage());
118     } else if (MO.getTargetFlags() == X86II::MO_DARWIN_STUB) {
119       MCSymbol *Sym = P.getSymbolWithGlobalValueBase(GV, "$stub");
120       MachineModuleInfoImpl::StubValueTy &StubSym =
121           P.MMI->getObjFileInfo<MachineModuleInfoMachO>().getFnStubEntry(Sym);
122       if (!StubSym.getPointer())
123         StubSym = MachineModuleInfoImpl::
124           StubValueTy(P.getSymbol(GV), !GV->hasInternalLinkage());
125     }
126 
127     // If the name begins with a dollar-sign, enclose it in parens.  We do this
128     // to avoid having it look like an integer immediate to the assembler.
129     if (GVSym->getName()[0] != '$')
130       GVSym->print(O, P.MAI);
131     else {
132       O << '(';
133       GVSym->print(O, P.MAI);
134       O << ')';
135     }
136     P.printOffset(MO.getOffset(), O);
137     break;
138   }
139   }
140 
141   switch (MO.getTargetFlags()) {
142   default:
143     llvm_unreachable("Unknown target flag on GV operand");
144   case X86II::MO_NO_FLAG:    // No flag.
145     break;
146   case X86II::MO_DARWIN_NONLAZY:
147   case X86II::MO_DLLIMPORT:
148   case X86II::MO_DARWIN_STUB:
149     // These affect the name of the symbol, not any suffix.
150     break;
151   case X86II::MO_GOT_ABSOLUTE_ADDRESS:
152     O << " + [.-";
153     P.MF->getPICBaseSymbol()->print(O, P.MAI);
154     O << ']';
155     break;
156   case X86II::MO_PIC_BASE_OFFSET:
157   case X86II::MO_DARWIN_NONLAZY_PIC_BASE:
158   case X86II::MO_DARWIN_HIDDEN_NONLAZY_PIC_BASE:
159     O << '-';
160     P.MF->getPICBaseSymbol()->print(O, P.MAI);
161     break;
162   case X86II::MO_TLSGD:     O << "@TLSGD";     break;
163   case X86II::MO_TLSLD:     O << "@TLSLD";     break;
164   case X86II::MO_TLSLDM:    O << "@TLSLDM";    break;
165   case X86II::MO_GOTTPOFF:  O << "@GOTTPOFF";  break;
166   case X86II::MO_INDNTPOFF: O << "@INDNTPOFF"; break;
167   case X86II::MO_TPOFF:     O << "@TPOFF";     break;
168   case X86II::MO_DTPOFF:    O << "@DTPOFF";    break;
169   case X86II::MO_NTPOFF:    O << "@NTPOFF";    break;
170   case X86II::MO_GOTNTPOFF: O << "@GOTNTPOFF"; break;
171   case X86II::MO_GOTPCREL:  O << "@GOTPCREL";  break;
172   case X86II::MO_GOT:       O << "@GOT";       break;
173   case X86II::MO_GOTOFF:    O << "@GOTOFF";    break;
174   case X86II::MO_PLT:       O << "@PLT";       break;
175   case X86II::MO_TLVP:      O << "@TLVP";      break;
176   case X86II::MO_TLVP_PIC_BASE:
177     O << "@TLVP" << '-';
178     P.MF->getPICBaseSymbol()->print(O, P.MAI);
179     break;
180   case X86II::MO_SECREL:    O << "@SECREL32";  break;
181   }
182 }
183 
184 static void printOperand(X86AsmPrinter &P, const MachineInstr *MI,
185                          unsigned OpNo, raw_ostream &O,
186                          const char *Modifier = nullptr, unsigned AsmVariant = 0);
187 
188 /// printPCRelImm - This is used to print an immediate value that ends up
189 /// being encoded as a pc-relative value.  These print slightly differently, for
190 /// example, a $ is not emitted.
printPCRelImm(X86AsmPrinter & P,const MachineInstr * MI,unsigned OpNo,raw_ostream & O)191 static void printPCRelImm(X86AsmPrinter &P, const MachineInstr *MI,
192                           unsigned OpNo, raw_ostream &O) {
193   const MachineOperand &MO = MI->getOperand(OpNo);
194   switch (MO.getType()) {
195   default: llvm_unreachable("Unknown pcrel immediate operand");
196   case MachineOperand::MO_Register:
197     // pc-relativeness was handled when computing the value in the reg.
198     printOperand(P, MI, OpNo, O);
199     return;
200   case MachineOperand::MO_Immediate:
201     O << MO.getImm();
202     return;
203   case MachineOperand::MO_GlobalAddress:
204     printSymbolOperand(P, MO, O);
205     return;
206   }
207 }
208 
printOperand(X86AsmPrinter & P,const MachineInstr * MI,unsigned OpNo,raw_ostream & O,const char * Modifier,unsigned AsmVariant)209 static void printOperand(X86AsmPrinter &P, const MachineInstr *MI,
210                          unsigned OpNo, raw_ostream &O, const char *Modifier,
211                          unsigned AsmVariant) {
212   const MachineOperand &MO = MI->getOperand(OpNo);
213   switch (MO.getType()) {
214   default: llvm_unreachable("unknown operand type!");
215   case MachineOperand::MO_Register: {
216     // FIXME: Enumerating AsmVariant, so we can remove magic number.
217     if (AsmVariant == 0) O << '%';
218     unsigned Reg = MO.getReg();
219     if (Modifier && strncmp(Modifier, "subreg", strlen("subreg")) == 0) {
220       MVT::SimpleValueType VT = (strcmp(Modifier+6,"64") == 0) ?
221         MVT::i64 : ((strcmp(Modifier+6, "32") == 0) ? MVT::i32 :
222                     ((strcmp(Modifier+6,"16") == 0) ? MVT::i16 : MVT::i8));
223       Reg = getX86SubSuperRegister(Reg, VT);
224     }
225     O << X86ATTInstPrinter::getRegisterName(Reg);
226     return;
227   }
228 
229   case MachineOperand::MO_Immediate:
230     if (AsmVariant == 0) O << '$';
231     O << MO.getImm();
232     return;
233 
234   case MachineOperand::MO_GlobalAddress: {
235     if (AsmVariant == 0) O << '$';
236     printSymbolOperand(P, MO, O);
237     break;
238   }
239   }
240 }
241 
printLeaMemReference(X86AsmPrinter & P,const MachineInstr * MI,unsigned Op,raw_ostream & O,const char * Modifier=nullptr)242 static void printLeaMemReference(X86AsmPrinter &P, const MachineInstr *MI,
243                                  unsigned Op, raw_ostream &O,
244                                  const char *Modifier = nullptr) {
245   const MachineOperand &BaseReg  = MI->getOperand(Op+X86::AddrBaseReg);
246   const MachineOperand &IndexReg = MI->getOperand(Op+X86::AddrIndexReg);
247   const MachineOperand &DispSpec = MI->getOperand(Op+X86::AddrDisp);
248 
249   // If we really don't want to print out (rip), don't.
250   bool HasBaseReg = BaseReg.getReg() != 0;
251   if (HasBaseReg && Modifier && !strcmp(Modifier, "no-rip") &&
252       BaseReg.getReg() == X86::RIP)
253     HasBaseReg = false;
254 
255   // HasParenPart - True if we will print out the () part of the mem ref.
256   bool HasParenPart = IndexReg.getReg() || HasBaseReg;
257 
258   switch (DispSpec.getType()) {
259   default:
260     llvm_unreachable("unknown operand type!");
261   case MachineOperand::MO_Immediate: {
262     int DispVal = DispSpec.getImm();
263     if (DispVal || !HasParenPart)
264       O << DispVal;
265     break;
266   }
267   case MachineOperand::MO_GlobalAddress:
268   case MachineOperand::MO_ConstantPoolIndex:
269     printSymbolOperand(P, DispSpec, O);
270   }
271 
272   if (Modifier && strcmp(Modifier, "H") == 0)
273     O << "+8";
274 
275   if (HasParenPart) {
276     assert(IndexReg.getReg() != X86::ESP &&
277            "X86 doesn't allow scaling by ESP");
278 
279     O << '(';
280     if (HasBaseReg)
281       printOperand(P, MI, Op+X86::AddrBaseReg, O, Modifier);
282 
283     if (IndexReg.getReg()) {
284       O << ',';
285       printOperand(P, MI, Op+X86::AddrIndexReg, O, Modifier);
286       unsigned ScaleVal = MI->getOperand(Op+X86::AddrScaleAmt).getImm();
287       if (ScaleVal != 1)
288         O << ',' << ScaleVal;
289     }
290     O << ')';
291   }
292 }
293 
printMemReference(X86AsmPrinter & P,const MachineInstr * MI,unsigned Op,raw_ostream & O,const char * Modifier=nullptr)294 static void printMemReference(X86AsmPrinter &P, const MachineInstr *MI,
295                               unsigned Op, raw_ostream &O,
296                               const char *Modifier = nullptr) {
297   assert(isMem(MI, Op) && "Invalid memory reference!");
298   const MachineOperand &Segment = MI->getOperand(Op+X86::AddrSegmentReg);
299   if (Segment.getReg()) {
300     printOperand(P, MI, Op+X86::AddrSegmentReg, O, Modifier);
301     O << ':';
302   }
303   printLeaMemReference(P, MI, Op, O, Modifier);
304 }
305 
printIntelMemReference(X86AsmPrinter & P,const MachineInstr * MI,unsigned Op,raw_ostream & O,const char * Modifier=nullptr,unsigned AsmVariant=1)306 static void printIntelMemReference(X86AsmPrinter &P, const MachineInstr *MI,
307                                    unsigned Op, raw_ostream &O,
308                                    const char *Modifier = nullptr,
309                                    unsigned AsmVariant = 1) {
310   const MachineOperand &BaseReg  = MI->getOperand(Op+X86::AddrBaseReg);
311   unsigned ScaleVal = MI->getOperand(Op+X86::AddrScaleAmt).getImm();
312   const MachineOperand &IndexReg = MI->getOperand(Op+X86::AddrIndexReg);
313   const MachineOperand &DispSpec = MI->getOperand(Op+X86::AddrDisp);
314   const MachineOperand &SegReg   = MI->getOperand(Op+X86::AddrSegmentReg);
315 
316   // If this has a segment register, print it.
317   if (SegReg.getReg()) {
318     printOperand(P, MI, Op+X86::AddrSegmentReg, O, Modifier, AsmVariant);
319     O << ':';
320   }
321 
322   O << '[';
323 
324   bool NeedPlus = false;
325   if (BaseReg.getReg()) {
326     printOperand(P, MI, Op+X86::AddrBaseReg, O, Modifier, AsmVariant);
327     NeedPlus = true;
328   }
329 
330   if (IndexReg.getReg()) {
331     if (NeedPlus) O << " + ";
332     if (ScaleVal != 1)
333       O << ScaleVal << '*';
334     printOperand(P, MI, Op+X86::AddrIndexReg, O, Modifier, AsmVariant);
335     NeedPlus = true;
336   }
337 
338   if (!DispSpec.isImm()) {
339     if (NeedPlus) O << " + ";
340     printOperand(P, MI, Op+X86::AddrDisp, O, Modifier, AsmVariant);
341   } else {
342     int64_t DispVal = DispSpec.getImm();
343     if (DispVal || (!IndexReg.getReg() && !BaseReg.getReg())) {
344       if (NeedPlus) {
345         if (DispVal > 0)
346           O << " + ";
347         else {
348           O << " - ";
349           DispVal = -DispVal;
350         }
351       }
352       O << DispVal;
353     }
354   }
355   O << ']';
356 }
357 
printAsmMRegister(X86AsmPrinter & P,const MachineOperand & MO,char Mode,raw_ostream & O)358 static bool printAsmMRegister(X86AsmPrinter &P, const MachineOperand &MO,
359                               char Mode, raw_ostream &O) {
360   unsigned Reg = MO.getReg();
361   switch (Mode) {
362   default: return true;  // Unknown mode.
363   case 'b': // Print QImode register
364     Reg = getX86SubSuperRegister(Reg, MVT::i8);
365     break;
366   case 'h': // Print QImode high register
367     Reg = getX86SubSuperRegister(Reg, MVT::i8, true);
368     break;
369   case 'w': // Print HImode register
370     Reg = getX86SubSuperRegister(Reg, MVT::i16);
371     break;
372   case 'k': // Print SImode register
373     Reg = getX86SubSuperRegister(Reg, MVT::i32);
374     break;
375   case 'q':
376     // Print 64-bit register names if 64-bit integer registers are available.
377     // Otherwise, print 32-bit register names.
378     MVT::SimpleValueType Ty = P.getSubtarget().is64Bit() ? MVT::i64 : MVT::i32;
379     Reg = getX86SubSuperRegister(Reg, Ty);
380     break;
381   }
382 
383   O << '%' << X86ATTInstPrinter::getRegisterName(Reg);
384   return false;
385 }
386 
387 /// PrintAsmOperand - Print out an operand for an inline asm expression.
388 ///
PrintAsmOperand(const MachineInstr * MI,unsigned OpNo,unsigned AsmVariant,const char * ExtraCode,raw_ostream & O)389 bool X86AsmPrinter::PrintAsmOperand(const MachineInstr *MI, unsigned OpNo,
390                                     unsigned AsmVariant,
391                                     const char *ExtraCode, raw_ostream &O) {
392   // Does this asm operand have a single letter operand modifier?
393   if (ExtraCode && ExtraCode[0]) {
394     if (ExtraCode[1] != 0) return true; // Unknown modifier.
395 
396     const MachineOperand &MO = MI->getOperand(OpNo);
397 
398     switch (ExtraCode[0]) {
399     default:
400       // See if this is a generic print operand
401       return AsmPrinter::PrintAsmOperand(MI, OpNo, AsmVariant, ExtraCode, O);
402     case 'a': // This is an address.  Currently only 'i' and 'r' are expected.
403       switch (MO.getType()) {
404       default:
405         return true;
406       case MachineOperand::MO_Immediate:
407         O << MO.getImm();
408         return false;
409       case MachineOperand::MO_ConstantPoolIndex:
410       case MachineOperand::MO_JumpTableIndex:
411       case MachineOperand::MO_ExternalSymbol:
412         llvm_unreachable("unexpected operand type!");
413       case MachineOperand::MO_GlobalAddress:
414         printSymbolOperand(*this, MO, O);
415         if (Subtarget->isPICStyleRIPRel())
416           O << "(%rip)";
417         return false;
418       case MachineOperand::MO_Register:
419         O << '(';
420         printOperand(*this, MI, OpNo, O);
421         O << ')';
422         return false;
423       }
424 
425     case 'c': // Don't print "$" before a global var name or constant.
426       switch (MO.getType()) {
427       default:
428         printOperand(*this, MI, OpNo, O);
429         break;
430       case MachineOperand::MO_Immediate:
431         O << MO.getImm();
432         break;
433       case MachineOperand::MO_ConstantPoolIndex:
434       case MachineOperand::MO_JumpTableIndex:
435       case MachineOperand::MO_ExternalSymbol:
436         llvm_unreachable("unexpected operand type!");
437       case MachineOperand::MO_GlobalAddress:
438         printSymbolOperand(*this, MO, O);
439         break;
440       }
441       return false;
442 
443     case 'A': // Print '*' before a register (it must be a register)
444       if (MO.isReg()) {
445         O << '*';
446         printOperand(*this, MI, OpNo, O);
447         return false;
448       }
449       return true;
450 
451     case 'b': // Print QImode register
452     case 'h': // Print QImode high register
453     case 'w': // Print HImode register
454     case 'k': // Print SImode register
455     case 'q': // Print DImode register
456       if (MO.isReg())
457         return printAsmMRegister(*this, MO, ExtraCode[0], O);
458       printOperand(*this, MI, OpNo, O);
459       return false;
460 
461     case 'P': // This is the operand of a call, treat specially.
462       printPCRelImm(*this, MI, OpNo, O);
463       return false;
464 
465     case 'n':  // Negate the immediate or print a '-' before the operand.
466       // Note: this is a temporary solution. It should be handled target
467       // independently as part of the 'MC' work.
468       if (MO.isImm()) {
469         O << -MO.getImm();
470         return false;
471       }
472       O << '-';
473     }
474   }
475 
476   printOperand(*this, MI, OpNo, O, /*Modifier*/ nullptr, AsmVariant);
477   return false;
478 }
479 
PrintAsmMemoryOperand(const MachineInstr * MI,unsigned OpNo,unsigned AsmVariant,const char * ExtraCode,raw_ostream & O)480 bool X86AsmPrinter::PrintAsmMemoryOperand(const MachineInstr *MI,
481                                           unsigned OpNo, unsigned AsmVariant,
482                                           const char *ExtraCode,
483                                           raw_ostream &O) {
484   if (AsmVariant) {
485     printIntelMemReference(*this, MI, OpNo, O);
486     return false;
487   }
488 
489   if (ExtraCode && ExtraCode[0]) {
490     if (ExtraCode[1] != 0) return true; // Unknown modifier.
491 
492     switch (ExtraCode[0]) {
493     default: return true;  // Unknown modifier.
494     case 'b': // Print QImode register
495     case 'h': // Print QImode high register
496     case 'w': // Print HImode register
497     case 'k': // Print SImode register
498     case 'q': // Print SImode register
499       // These only apply to registers, ignore on mem.
500       break;
501     case 'H':
502       printMemReference(*this, MI, OpNo, O, "H");
503       return false;
504     case 'P': // Don't print @PLT, but do print as memory.
505       printMemReference(*this, MI, OpNo, O, "no-rip");
506       return false;
507     }
508   }
509   printMemReference(*this, MI, OpNo, O);
510   return false;
511 }
512 
EmitStartOfAsmFile(Module & M)513 void X86AsmPrinter::EmitStartOfAsmFile(Module &M) {
514   const Triple &TT = TM.getTargetTriple();
515 
516   if (TT.isOSBinFormatMachO())
517     OutStreamer->SwitchSection(getObjFileLowering().getTextSection());
518 
519   if (TT.isOSBinFormatCOFF()) {
520     // Emit an absolute @feat.00 symbol.  This appears to be some kind of
521     // compiler features bitfield read by link.exe.
522     if (TT.getArch() == Triple::x86) {
523       MCSymbol *S = MMI->getContext().getOrCreateSymbol(StringRef("@feat.00"));
524       OutStreamer->BeginCOFFSymbolDef(S);
525       OutStreamer->EmitCOFFSymbolStorageClass(COFF::IMAGE_SYM_CLASS_STATIC);
526       OutStreamer->EmitCOFFSymbolType(COFF::IMAGE_SYM_DTYPE_NULL);
527       OutStreamer->EndCOFFSymbolDef();
528       // According to the PE-COFF spec, the LSB of this value marks the object
529       // for "registered SEH".  This means that all SEH handler entry points
530       // must be registered in .sxdata.  Use of any unregistered handlers will
531       // cause the process to terminate immediately.  LLVM does not know how to
532       // register any SEH handlers, so its object files should be safe.
533       OutStreamer->EmitSymbolAttribute(S, MCSA_Global);
534       OutStreamer->EmitAssignment(
535           S, MCConstantExpr::create(int64_t(1), MMI->getContext()));
536     }
537   }
538   OutStreamer->EmitSyntaxDirective();
539 }
540 
541 static void
emitNonLazySymbolPointer(MCStreamer & OutStreamer,MCSymbol * StubLabel,MachineModuleInfoImpl::StubValueTy & MCSym)542 emitNonLazySymbolPointer(MCStreamer &OutStreamer, MCSymbol *StubLabel,
543                          MachineModuleInfoImpl::StubValueTy &MCSym) {
544   // L_foo$stub:
545   OutStreamer.EmitLabel(StubLabel);
546   //   .indirect_symbol _foo
547   OutStreamer.EmitSymbolAttribute(MCSym.getPointer(), MCSA_IndirectSymbol);
548 
549   if (MCSym.getInt())
550     // External to current translation unit.
551     OutStreamer.EmitIntValue(0, 4/*size*/);
552   else
553     // Internal to current translation unit.
554     //
555     // When we place the LSDA into the TEXT section, the type info
556     // pointers need to be indirect and pc-rel. We accomplish this by
557     // using NLPs; however, sometimes the types are local to the file.
558     // We need to fill in the value for the NLP in those cases.
559     OutStreamer.EmitValue(
560         MCSymbolRefExpr::create(MCSym.getPointer(), OutStreamer.getContext()),
561         4 /*size*/);
562 }
563 
GetCPISymbol(unsigned CPID) const564 MCSymbol *X86AsmPrinter::GetCPISymbol(unsigned CPID) const {
565   if (Subtarget->isTargetKnownWindowsMSVC()) {
566     const MachineConstantPoolEntry &CPE =
567         MF->getConstantPool()->getConstants()[CPID];
568     if (!CPE.isMachineConstantPoolEntry()) {
569       const DataLayout &DL = MF->getDataLayout();
570       SectionKind Kind = CPE.getSectionKind(&DL);
571       const Constant *C = CPE.Val.ConstVal;
572       if (const MCSectionCOFF *S = dyn_cast<MCSectionCOFF>(
573               getObjFileLowering().getSectionForConstant(DL, Kind, C))) {
574         if (MCSymbol *Sym = S->getCOMDATSymbol()) {
575           if (Sym->isUndefined())
576             OutStreamer->EmitSymbolAttribute(Sym, MCSA_Global);
577           return Sym;
578         }
579       }
580     }
581   }
582 
583   return AsmPrinter::GetCPISymbol(CPID);
584 }
585 
EmitEndOfAsmFile(Module & M)586 void X86AsmPrinter::EmitEndOfAsmFile(Module &M) {
587   const Triple &TT = TM.getTargetTriple();
588 
589   if (TT.isOSBinFormatMachO()) {
590     // All darwin targets use mach-o.
591     MachineModuleInfoMachO &MMIMacho =
592         MMI->getObjFileInfo<MachineModuleInfoMachO>();
593 
594     // Output stubs for dynamically-linked functions.
595     MachineModuleInfoMachO::SymbolListTy Stubs;
596 
597     Stubs = MMIMacho.GetFnStubList();
598     if (!Stubs.empty()) {
599       MCSection *TheSection = OutContext.getMachOSection(
600           "__IMPORT", "__jump_table",
601           MachO::S_SYMBOL_STUBS | MachO::S_ATTR_SELF_MODIFYING_CODE |
602               MachO::S_ATTR_PURE_INSTRUCTIONS,
603           5, SectionKind::getMetadata());
604       OutStreamer->SwitchSection(TheSection);
605 
606       for (const auto &Stub : Stubs) {
607         // L_foo$stub:
608         OutStreamer->EmitLabel(Stub.first);
609         //   .indirect_symbol _foo
610         OutStreamer->EmitSymbolAttribute(Stub.second.getPointer(),
611                                          MCSA_IndirectSymbol);
612         // hlt; hlt; hlt; hlt; hlt     hlt = 0xf4.
613         const char HltInsts[] = "\xf4\xf4\xf4\xf4\xf4";
614         OutStreamer->EmitBytes(StringRef(HltInsts, 5));
615       }
616 
617       Stubs.clear();
618       OutStreamer->AddBlankLine();
619     }
620 
621     // Output stubs for external and common global variables.
622     Stubs = MMIMacho.GetGVStubList();
623     if (!Stubs.empty()) {
624       MCSection *TheSection = OutContext.getMachOSection(
625           "__IMPORT", "__pointers", MachO::S_NON_LAZY_SYMBOL_POINTERS,
626           SectionKind::getMetadata());
627       OutStreamer->SwitchSection(TheSection);
628 
629       for (auto &Stub : Stubs)
630         emitNonLazySymbolPointer(*OutStreamer, Stub.first, Stub.second);
631 
632       Stubs.clear();
633       OutStreamer->AddBlankLine();
634     }
635 
636     Stubs = MMIMacho.GetHiddenGVStubList();
637     if (!Stubs.empty()) {
638       MCSection *TheSection = OutContext.getMachOSection(
639           "__IMPORT", "__pointers", MachO::S_NON_LAZY_SYMBOL_POINTERS,
640           SectionKind::getMetadata());
641       OutStreamer->SwitchSection(TheSection);
642 
643       for (auto &Stub : Stubs)
644         emitNonLazySymbolPointer(*OutStreamer, Stub.first, Stub.second);
645 
646       Stubs.clear();
647       OutStreamer->AddBlankLine();
648     }
649 
650     SM.serializeToStackMapSection();
651     FM.serializeToFaultMapSection();
652 
653     // Funny Darwin hack: This flag tells the linker that no global symbols
654     // contain code that falls through to other global symbols (e.g. the obvious
655     // implementation of multiple entry points).  If this doesn't occur, the
656     // linker can safely perform dead code stripping.  Since LLVM never
657     // generates code that does this, it is always safe to set.
658     OutStreamer->EmitAssemblerFlag(MCAF_SubsectionsViaSymbols);
659   }
660 
661   if (TT.isKnownWindowsMSVCEnvironment() && MMI->usesVAFloatArgument()) {
662     StringRef SymbolName =
663         (TT.getArch() == Triple::x86_64) ? "_fltused" : "__fltused";
664     MCSymbol *S = MMI->getContext().getOrCreateSymbol(SymbolName);
665     OutStreamer->EmitSymbolAttribute(S, MCSA_Global);
666   }
667 
668   if (TT.isOSBinFormatCOFF()) {
669     const TargetLoweringObjectFileCOFF &TLOFCOFF =
670         static_cast<const TargetLoweringObjectFileCOFF&>(getObjFileLowering());
671 
672     std::string Flags;
673     raw_string_ostream FlagsOS(Flags);
674 
675     for (const auto &Function : M)
676       TLOFCOFF.emitLinkerFlagsForGlobal(FlagsOS, &Function, *Mang);
677     for (const auto &Global : M.globals())
678       TLOFCOFF.emitLinkerFlagsForGlobal(FlagsOS, &Global, *Mang);
679     for (const auto &Alias : M.aliases())
680       TLOFCOFF.emitLinkerFlagsForGlobal(FlagsOS, &Alias, *Mang);
681 
682     FlagsOS.flush();
683 
684     // Output collected flags.
685     if (!Flags.empty()) {
686       OutStreamer->SwitchSection(TLOFCOFF.getDrectveSection());
687       OutStreamer->EmitBytes(Flags);
688     }
689 
690     SM.serializeToStackMapSection();
691   }
692 
693   if (TT.isOSBinFormatELF()) {
694     SM.serializeToStackMapSection();
695     FM.serializeToFaultMapSection();
696   }
697 }
698 
699 //===----------------------------------------------------------------------===//
700 // Target Registry Stuff
701 //===----------------------------------------------------------------------===//
702 
703 // Force static initialization.
LLVMInitializeX86AsmPrinter()704 extern "C" void LLVMInitializeX86AsmPrinter() {
705   RegisterAsmPrinter<X86AsmPrinter> X(TheX86_32Target);
706   RegisterAsmPrinter<X86AsmPrinter> Y(TheX86_64Target);
707 }
708