1 //===-- AsmPrinterInlineAsm.cpp - AsmPrinter Inline Asm Handling ----------===// 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 implements the inline assembler pieces of the AsmPrinter class. 11 // 12 //===----------------------------------------------------------------------===// 13 14 #define DEBUG_TYPE "asm-printer" 15 #include "llvm/CodeGen/AsmPrinter.h" 16 #include "llvm/Constants.h" 17 #include "llvm/InlineAsm.h" 18 #include "llvm/LLVMContext.h" 19 #include "llvm/Module.h" 20 #include "llvm/CodeGen/MachineBasicBlock.h" 21 #include "llvm/CodeGen/MachineModuleInfo.h" 22 #include "llvm/MC/MCAsmInfo.h" 23 #include "llvm/MC/MCStreamer.h" 24 #include "llvm/MC/MCSubtargetInfo.h" 25 #include "llvm/MC/MCSymbol.h" 26 #include "llvm/MC/MCTargetAsmParser.h" 27 #include "llvm/Target/TargetMachine.h" 28 #include "llvm/ADT/OwningPtr.h" 29 #include "llvm/ADT/SmallString.h" 30 #include "llvm/ADT/Twine.h" 31 #include "llvm/Support/ErrorHandling.h" 32 #include "llvm/Support/MemoryBuffer.h" 33 #include "llvm/Support/SourceMgr.h" 34 #include "llvm/Support/TargetRegistry.h" 35 #include "llvm/Support/raw_ostream.h" 36 using namespace llvm; 37 38 namespace { 39 struct SrcMgrDiagInfo { 40 const MDNode *LocInfo; 41 LLVMContext::InlineAsmDiagHandlerTy DiagHandler; 42 void *DiagContext; 43 }; 44 } 45 46 /// srcMgrDiagHandler - This callback is invoked when the SourceMgr for an 47 /// inline asm has an error in it. diagInfo is a pointer to the SrcMgrDiagInfo 48 /// struct above. 49 static void srcMgrDiagHandler(const SMDiagnostic &Diag, void *diagInfo) { 50 SrcMgrDiagInfo *DiagInfo = static_cast<SrcMgrDiagInfo *>(diagInfo); 51 assert(DiagInfo && "Diagnostic context not passed down?"); 52 53 // If the inline asm had metadata associated with it, pull out a location 54 // cookie corresponding to which line the error occurred on. 55 unsigned LocCookie = 0; 56 if (const MDNode *LocInfo = DiagInfo->LocInfo) { 57 unsigned ErrorLine = Diag.getLineNo()-1; 58 if (ErrorLine >= LocInfo->getNumOperands()) 59 ErrorLine = 0; 60 61 if (LocInfo->getNumOperands() != 0) 62 if (const ConstantInt *CI = 63 dyn_cast<ConstantInt>(LocInfo->getOperand(ErrorLine))) 64 LocCookie = CI->getZExtValue(); 65 } 66 67 DiagInfo->DiagHandler(Diag, DiagInfo->DiagContext, LocCookie); 68 } 69 70 /// EmitInlineAsm - Emit a blob of inline asm to the output streamer. 71 void AsmPrinter::EmitInlineAsm(StringRef Str, const MDNode *LocMDNode, 72 InlineAsm::AsmDialect Dialect) const { 73 #ifndef ANDROID_TARGET_BUILD 74 assert(!Str.empty() && "Can't emit empty inline asm block"); 75 76 // Remember if the buffer is nul terminated or not so we can avoid a copy. 77 bool isNullTerminated = Str.back() == 0; 78 if (isNullTerminated) 79 Str = Str.substr(0, Str.size()-1); 80 81 // If the output streamer is actually a .s file, just emit the blob textually. 82 // This is useful in case the asm parser doesn't handle something but the 83 // system assembler does. 84 if (OutStreamer.hasRawTextSupport()) { 85 OutStreamer.EmitRawText(Str); 86 return; 87 } 88 89 SourceMgr SrcMgr; 90 SrcMgrDiagInfo DiagInfo; 91 92 // If the current LLVMContext has an inline asm handler, set it in SourceMgr. 93 LLVMContext &LLVMCtx = MMI->getModule()->getContext(); 94 bool HasDiagHandler = false; 95 if (LLVMCtx.getInlineAsmDiagnosticHandler() != 0) { 96 // If the source manager has an issue, we arrange for srcMgrDiagHandler 97 // to be invoked, getting DiagInfo passed into it. 98 DiagInfo.LocInfo = LocMDNode; 99 DiagInfo.DiagHandler = LLVMCtx.getInlineAsmDiagnosticHandler(); 100 DiagInfo.DiagContext = LLVMCtx.getInlineAsmDiagnosticContext(); 101 SrcMgr.setDiagHandler(srcMgrDiagHandler, &DiagInfo); 102 HasDiagHandler = true; 103 } 104 105 MemoryBuffer *Buffer; 106 if (isNullTerminated) 107 Buffer = MemoryBuffer::getMemBuffer(Str, "<inline asm>"); 108 else 109 Buffer = MemoryBuffer::getMemBufferCopy(Str, "<inline asm>"); 110 111 // Tell SrcMgr about this buffer, it takes ownership of the buffer. 112 SrcMgr.AddNewSourceBuffer(Buffer, SMLoc()); 113 114 OwningPtr<MCAsmParser> Parser(createMCAsmParser(SrcMgr, 115 OutContext, OutStreamer, 116 *MAI)); 117 118 // FIXME: It would be nice if we can avoid createing a new instance of 119 // MCSubtargetInfo here given TargetSubtargetInfo is available. However, 120 // we have to watch out for asm directives which can change subtarget 121 // state. e.g. .code 16, .code 32. 122 OwningPtr<MCSubtargetInfo> 123 STI(TM.getTarget().createMCSubtargetInfo(TM.getTargetTriple(), 124 TM.getTargetCPU(), 125 TM.getTargetFeatureString())); 126 OwningPtr<MCTargetAsmParser> 127 TAP(TM.getTarget().createMCAsmParser(*STI, *Parser)); 128 if (!TAP) 129 report_fatal_error("Inline asm not supported by this streamer because" 130 " we don't have an asm parser for this target\n"); 131 Parser->setAssemblerDialect(Dialect); 132 Parser->setTargetParser(*TAP.get()); 133 134 // Don't implicitly switch to the text section before the asm. 135 int Res = Parser->Run(/*NoInitialTextSection*/ true, 136 /*NoFinalize*/ true); 137 if (Res && !HasDiagHandler) 138 report_fatal_error("Error parsing inline asm\n"); 139 #endif // ANDROID_TARGET_BUILD 140 } 141 142 143 /// EmitInlineAsm - This method formats and emits the specified machine 144 /// instruction that is an inline asm. 145 void AsmPrinter::EmitInlineAsm(const MachineInstr *MI) const { 146 #ifndef ANDROID_TARGET_BUILD 147 assert(MI->isInlineAsm() && "printInlineAsm only works on inline asms"); 148 149 unsigned NumOperands = MI->getNumOperands(); 150 151 // Count the number of register definitions to find the asm string. 152 unsigned NumDefs = 0; 153 for (; MI->getOperand(NumDefs).isReg() && MI->getOperand(NumDefs).isDef(); 154 ++NumDefs) 155 assert(NumDefs != NumOperands-2 && "No asm string?"); 156 157 assert(MI->getOperand(NumDefs).isSymbol() && "No asm string?"); 158 159 // Disassemble the AsmStr, printing out the literal pieces, the operands, etc. 160 const char *AsmStr = MI->getOperand(NumDefs).getSymbolName(); 161 162 // If this asmstr is empty, just print the #APP/#NOAPP markers. 163 // These are useful to see where empty asm's wound up. 164 if (AsmStr[0] == 0) { 165 // Don't emit the comments if writing to a .o file. 166 if (!OutStreamer.hasRawTextSupport()) return; 167 168 OutStreamer.EmitRawText(Twine("\t")+MAI->getCommentString()+ 169 MAI->getInlineAsmStart()); 170 OutStreamer.EmitRawText(Twine("\t")+MAI->getCommentString()+ 171 MAI->getInlineAsmEnd()); 172 return; 173 } 174 175 // Emit the #APP start marker. This has to happen even if verbose-asm isn't 176 // enabled, so we use EmitRawText. 177 if (OutStreamer.hasRawTextSupport()) 178 OutStreamer.EmitRawText(Twine("\t")+MAI->getCommentString()+ 179 MAI->getInlineAsmStart()); 180 181 // Get the !srcloc metadata node if we have it, and decode the loc cookie from 182 // it. 183 unsigned LocCookie = 0; 184 const MDNode *LocMD = 0; 185 for (unsigned i = MI->getNumOperands(); i != 0; --i) { 186 if (MI->getOperand(i-1).isMetadata() && 187 (LocMD = MI->getOperand(i-1).getMetadata()) && 188 LocMD->getNumOperands() != 0) { 189 if (const ConstantInt *CI = dyn_cast<ConstantInt>(LocMD->getOperand(0))) { 190 LocCookie = CI->getZExtValue(); 191 break; 192 } 193 } 194 } 195 196 // Emit the inline asm to a temporary string so we can emit it through 197 // EmitInlineAsm. 198 SmallString<256> StringData; 199 raw_svector_ostream OS(StringData); 200 201 OS << '\t'; 202 203 // The variant of the current asmprinter. 204 int AsmPrinterVariant = MAI->getAssemblerDialect(); 205 int InlineAsmVariant = MI->getInlineAsmDialect(); 206 207 // Switch to the inline assembly variant. 208 if (AsmPrinterVariant != InlineAsmVariant) { 209 if (InlineAsmVariant == 0) 210 OS << ".att_syntax\n\t"; 211 else 212 OS << ".intel_syntax\n\t"; 213 } 214 215 int CurVariant = -1; // The number of the {.|.|.} region we are in. 216 const char *LastEmitted = AsmStr; // One past the last character emitted. 217 218 while (*LastEmitted) { 219 switch (*LastEmitted) { 220 default: { 221 // Not a special case, emit the string section literally. 222 const char *LiteralEnd = LastEmitted+1; 223 while (*LiteralEnd && *LiteralEnd != '{' && *LiteralEnd != '|' && 224 *LiteralEnd != '}' && *LiteralEnd != '$' && *LiteralEnd != '\n') 225 ++LiteralEnd; 226 if (CurVariant == -1 || CurVariant == AsmPrinterVariant) 227 OS.write(LastEmitted, LiteralEnd-LastEmitted); 228 LastEmitted = LiteralEnd; 229 break; 230 } 231 case '\n': 232 ++LastEmitted; // Consume newline character. 233 OS << '\n'; // Indent code with newline. 234 break; 235 case '$': { 236 ++LastEmitted; // Consume '$' character. 237 bool Done = true; 238 239 // Handle escapes. 240 switch (*LastEmitted) { 241 default: Done = false; break; 242 case '$': // $$ -> $ 243 if (CurVariant == -1 || CurVariant == AsmPrinterVariant) 244 OS << '$'; 245 ++LastEmitted; // Consume second '$' character. 246 break; 247 case '(': // $( -> same as GCC's { character. 248 ++LastEmitted; // Consume '(' character. 249 if (CurVariant != -1) 250 report_fatal_error("Nested variants found in inline asm string: '" + 251 Twine(AsmStr) + "'"); 252 CurVariant = 0; // We're in the first variant now. 253 break; 254 case '|': 255 ++LastEmitted; // consume '|' character. 256 if (CurVariant == -1) 257 OS << '|'; // this is gcc's behavior for | outside a variant 258 else 259 ++CurVariant; // We're in the next variant. 260 break; 261 case ')': // $) -> same as GCC's } char. 262 ++LastEmitted; // consume ')' character. 263 if (CurVariant == -1) 264 OS << '}'; // this is gcc's behavior for } outside a variant 265 else 266 CurVariant = -1; 267 break; 268 } 269 if (Done) break; 270 271 bool HasCurlyBraces = false; 272 if (*LastEmitted == '{') { // ${variable} 273 ++LastEmitted; // Consume '{' character. 274 HasCurlyBraces = true; 275 } 276 277 // If we have ${:foo}, then this is not a real operand reference, it is a 278 // "magic" string reference, just like in .td files. Arrange to call 279 // PrintSpecial. 280 if (HasCurlyBraces && *LastEmitted == ':') { 281 ++LastEmitted; 282 const char *StrStart = LastEmitted; 283 const char *StrEnd = strchr(StrStart, '}'); 284 if (StrEnd == 0) 285 report_fatal_error("Unterminated ${:foo} operand in inline asm" 286 " string: '" + Twine(AsmStr) + "'"); 287 288 std::string Val(StrStart, StrEnd); 289 PrintSpecial(MI, OS, Val.c_str()); 290 LastEmitted = StrEnd+1; 291 break; 292 } 293 294 const char *IDStart = LastEmitted; 295 const char *IDEnd = IDStart; 296 while (*IDEnd >= '0' && *IDEnd <= '9') ++IDEnd; 297 298 unsigned Val; 299 if (StringRef(IDStart, IDEnd-IDStart).getAsInteger(10, Val)) 300 report_fatal_error("Bad $ operand number in inline asm string: '" + 301 Twine(AsmStr) + "'"); 302 LastEmitted = IDEnd; 303 304 char Modifier[2] = { 0, 0 }; 305 306 if (HasCurlyBraces) { 307 // If we have curly braces, check for a modifier character. This 308 // supports syntax like ${0:u}, which correspond to "%u0" in GCC asm. 309 if (*LastEmitted == ':') { 310 ++LastEmitted; // Consume ':' character. 311 if (*LastEmitted == 0) 312 report_fatal_error("Bad ${:} expression in inline asm string: '" + 313 Twine(AsmStr) + "'"); 314 315 Modifier[0] = *LastEmitted; 316 ++LastEmitted; // Consume modifier character. 317 } 318 319 if (*LastEmitted != '}') 320 report_fatal_error("Bad ${} expression in inline asm string: '" + 321 Twine(AsmStr) + "'"); 322 ++LastEmitted; // Consume '}' character. 323 } 324 325 if (Val >= NumOperands-1) 326 report_fatal_error("Invalid $ operand number in inline asm string: '" + 327 Twine(AsmStr) + "'"); 328 329 // Okay, we finally have a value number. Ask the target to print this 330 // operand! 331 if (CurVariant == -1 || CurVariant == AsmPrinterVariant) { 332 unsigned OpNo = InlineAsm::MIOp_FirstOperand; 333 334 bool Error = false; 335 336 // Scan to find the machine operand number for the operand. 337 for (; Val; --Val) { 338 if (OpNo >= MI->getNumOperands()) break; 339 unsigned OpFlags = MI->getOperand(OpNo).getImm(); 340 OpNo += InlineAsm::getNumOperandRegisters(OpFlags) + 1; 341 } 342 343 // We may have a location metadata attached to the end of the 344 // instruction, and at no point should see metadata at any 345 // other point while processing. It's an error if so. 346 if (OpNo >= MI->getNumOperands() || 347 MI->getOperand(OpNo).isMetadata()) { 348 Error = true; 349 } else { 350 unsigned OpFlags = MI->getOperand(OpNo).getImm(); 351 ++OpNo; // Skip over the ID number. 352 353 if (Modifier[0] == 'l') // labels are target independent 354 // FIXME: What if the operand isn't an MBB, report error? 355 OS << *MI->getOperand(OpNo).getMBB()->getSymbol(); 356 else { 357 AsmPrinter *AP = const_cast<AsmPrinter*>(this); 358 if (InlineAsm::isMemKind(OpFlags)) { 359 Error = AP->PrintAsmMemoryOperand(MI, OpNo, InlineAsmVariant, 360 Modifier[0] ? Modifier : 0, 361 OS); 362 } else { 363 Error = AP->PrintAsmOperand(MI, OpNo, InlineAsmVariant, 364 Modifier[0] ? Modifier : 0, OS); 365 } 366 } 367 } 368 if (Error) { 369 std::string msg; 370 raw_string_ostream Msg(msg); 371 Msg << "invalid operand in inline asm: '" << AsmStr << "'"; 372 MMI->getModule()->getContext().emitError(LocCookie, Msg.str()); 373 } 374 } 375 break; 376 } 377 } 378 } 379 // Switch to the AsmPrinter variant. 380 if (AsmPrinterVariant != InlineAsmVariant) { 381 if (AsmPrinterVariant == 0) 382 OS << "\n\t.att_syntax"; 383 else 384 OS << "\n\t.intel_syntax"; 385 } 386 387 OS << '\n' << (char)0; // null terminate string. 388 EmitInlineAsm(OS.str(), LocMD, MI->getInlineAsmDialect()); 389 390 // Emit the #NOAPP end marker. This has to happen even if verbose-asm isn't 391 // enabled, so we use EmitRawText. 392 if (OutStreamer.hasRawTextSupport()) 393 OutStreamer.EmitRawText(Twine("\t")+MAI->getCommentString()+ 394 MAI->getInlineAsmEnd()); 395 #endif // ANDROID_TARGET_BUILD 396 } 397 398 399 /// PrintSpecial - Print information related to the specified machine instr 400 /// that is independent of the operand, and may be independent of the instr 401 /// itself. This can be useful for portably encoding the comment character 402 /// or other bits of target-specific knowledge into the asmstrings. The 403 /// syntax used is ${:comment}. Targets can override this to add support 404 /// for their own strange codes. 405 void AsmPrinter::PrintSpecial(const MachineInstr *MI, raw_ostream &OS, 406 const char *Code) const { 407 if (!strcmp(Code, "private")) { 408 OS << MAI->getPrivateGlobalPrefix(); 409 } else if (!strcmp(Code, "comment")) { 410 OS << MAI->getCommentString(); 411 } else if (!strcmp(Code, "uid")) { 412 // Comparing the address of MI isn't sufficient, because machineinstrs may 413 // be allocated to the same address across functions. 414 415 // If this is a new LastFn instruction, bump the counter. 416 if (LastMI != MI || LastFn != getFunctionNumber()) { 417 ++Counter; 418 LastMI = MI; 419 LastFn = getFunctionNumber(); 420 } 421 OS << Counter; 422 } else { 423 std::string msg; 424 raw_string_ostream Msg(msg); 425 Msg << "Unknown special formatter '" << Code 426 << "' for machine instr: " << *MI; 427 report_fatal_error(Msg.str()); 428 } 429 } 430 431 /// PrintAsmOperand - Print the specified operand of MI, an INLINEASM 432 /// instruction, using the specified assembler variant. Targets should 433 /// override this to format as appropriate. 434 bool AsmPrinter::PrintAsmOperand(const MachineInstr *MI, unsigned OpNo, 435 unsigned AsmVariant, const char *ExtraCode, 436 raw_ostream &O) { 437 // Does this asm operand have a single letter operand modifier? 438 if (ExtraCode && ExtraCode[0]) { 439 if (ExtraCode[1] != 0) return true; // Unknown modifier. 440 441 const MachineOperand &MO = MI->getOperand(OpNo); 442 switch (ExtraCode[0]) { 443 default: 444 return true; // Unknown modifier. 445 case 'c': // Substitute immediate value without immediate syntax 446 if (MO.getType() != MachineOperand::MO_Immediate) 447 return true; 448 O << MO.getImm(); 449 return false; 450 case 'n': // Negate the immediate constant. 451 if (MO.getType() != MachineOperand::MO_Immediate) 452 return true; 453 O << -MO.getImm(); 454 return false; 455 } 456 } 457 return true; 458 } 459 460 bool AsmPrinter::PrintAsmMemoryOperand(const MachineInstr *MI, unsigned OpNo, 461 unsigned AsmVariant, 462 const char *ExtraCode, raw_ostream &O) { 463 // Target doesn't support this yet! 464 return true; 465 } 466 467