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