1 //===- MipsAsmPrinter.cpp - Mips LLVM Assembly Printer --------------------===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 // 9 // This file contains a printer that converts from our internal representation 10 // of machine-dependent LLVM code to GAS-format MIPS assembly language. 11 // 12 //===----------------------------------------------------------------------===// 13 14 #include "MipsAsmPrinter.h" 15 #include "InstPrinter/MipsInstPrinter.h" 16 #include "MCTargetDesc/MipsABIInfo.h" 17 #include "MCTargetDesc/MipsBaseInfo.h" 18 #include "MCTargetDesc/MipsMCNaCl.h" 19 #include "MCTargetDesc/MipsMCTargetDesc.h" 20 #include "Mips.h" 21 #include "MipsMCInstLower.h" 22 #include "MipsMachineFunction.h" 23 #include "MipsSubtarget.h" 24 #include "MipsTargetMachine.h" 25 #include "MipsTargetStreamer.h" 26 #include "llvm/ADT/SmallString.h" 27 #include "llvm/ADT/StringRef.h" 28 #include "llvm/ADT/Triple.h" 29 #include "llvm/ADT/Twine.h" 30 #include "llvm/BinaryFormat/ELF.h" 31 #include "llvm/CodeGen/MachineBasicBlock.h" 32 #include "llvm/CodeGen/MachineConstantPool.h" 33 #include "llvm/CodeGen/MachineFrameInfo.h" 34 #include "llvm/CodeGen/MachineFunction.h" 35 #include "llvm/CodeGen/MachineInstr.h" 36 #include "llvm/CodeGen/MachineJumpTableInfo.h" 37 #include "llvm/CodeGen/MachineOperand.h" 38 #include "llvm/CodeGen/TargetRegisterInfo.h" 39 #include "llvm/CodeGen/TargetSubtargetInfo.h" 40 #include "llvm/IR/Attributes.h" 41 #include "llvm/IR/BasicBlock.h" 42 #include "llvm/IR/DataLayout.h" 43 #include "llvm/IR/Function.h" 44 #include "llvm/IR/InlineAsm.h" 45 #include "llvm/IR/Instructions.h" 46 #include "llvm/MC/MCContext.h" 47 #include "llvm/MC/MCExpr.h" 48 #include "llvm/MC/MCInst.h" 49 #include "llvm/MC/MCInstBuilder.h" 50 #include "llvm/MC/MCObjectFileInfo.h" 51 #include "llvm/MC/MCSectionELF.h" 52 #include "llvm/MC/MCSymbol.h" 53 #include "llvm/MC/MCSymbolELF.h" 54 #include "llvm/Support/Casting.h" 55 #include "llvm/Support/ErrorHandling.h" 56 #include "llvm/Support/TargetRegistry.h" 57 #include "llvm/Support/raw_ostream.h" 58 #include "llvm/Target/TargetMachine.h" 59 #include <cassert> 60 #include <cstdint> 61 #include <map> 62 #include <memory> 63 #include <string> 64 #include <vector> 65 66 using namespace llvm; 67 68 #define DEBUG_TYPE "mips-asm-printer" 69 70 extern cl::opt<bool> EmitJalrReloc; 71 72 MipsTargetStreamer &MipsAsmPrinter::getTargetStreamer() const { 73 return static_cast<MipsTargetStreamer &>(*OutStreamer->getTargetStreamer()); 74 } 75 76 bool MipsAsmPrinter::runOnMachineFunction(MachineFunction &MF) { 77 Subtarget = &MF.getSubtarget<MipsSubtarget>(); 78 79 MipsFI = MF.getInfo<MipsFunctionInfo>(); 80 if (Subtarget->inMips16Mode()) 81 for (std::map< 82 const char *, 83 const Mips16HardFloatInfo::FuncSignature *>::const_iterator 84 it = MipsFI->StubsNeeded.begin(); 85 it != MipsFI->StubsNeeded.end(); ++it) { 86 const char *Symbol = it->first; 87 const Mips16HardFloatInfo::FuncSignature *Signature = it->second; 88 if (StubsNeeded.find(Symbol) == StubsNeeded.end()) 89 StubsNeeded[Symbol] = Signature; 90 } 91 MCP = MF.getConstantPool(); 92 93 // In NaCl, all indirect jump targets must be aligned to bundle size. 94 if (Subtarget->isTargetNaCl()) 95 NaClAlignIndirectJumpTargets(MF); 96 97 AsmPrinter::runOnMachineFunction(MF); 98 99 emitXRayTable(); 100 101 return true; 102 } 103 104 bool MipsAsmPrinter::lowerOperand(const MachineOperand &MO, MCOperand &MCOp) { 105 MCOp = MCInstLowering.LowerOperand(MO); 106 return MCOp.isValid(); 107 } 108 109 #include "MipsGenMCPseudoLowering.inc" 110 111 // Lower PseudoReturn/PseudoIndirectBranch/PseudoIndirectBranch64 to JR, JR_MM, 112 // JALR, or JALR64 as appropriate for the target. 113 void MipsAsmPrinter::emitPseudoIndirectBranch(MCStreamer &OutStreamer, 114 const MachineInstr *MI) { 115 bool HasLinkReg = false; 116 bool InMicroMipsMode = Subtarget->inMicroMipsMode(); 117 MCInst TmpInst0; 118 119 if (Subtarget->hasMips64r6()) { 120 // MIPS64r6 should use (JALR64 ZERO_64, $rs) 121 TmpInst0.setOpcode(Mips::JALR64); 122 HasLinkReg = true; 123 } else if (Subtarget->hasMips32r6()) { 124 // MIPS32r6 should use (JALR ZERO, $rs) 125 if (InMicroMipsMode) 126 TmpInst0.setOpcode(Mips::JRC16_MMR6); 127 else { 128 TmpInst0.setOpcode(Mips::JALR); 129 HasLinkReg = true; 130 } 131 } else if (Subtarget->inMicroMipsMode()) 132 // microMIPS should use (JR_MM $rs) 133 TmpInst0.setOpcode(Mips::JR_MM); 134 else { 135 // Everything else should use (JR $rs) 136 TmpInst0.setOpcode(Mips::JR); 137 } 138 139 MCOperand MCOp; 140 141 if (HasLinkReg) { 142 unsigned ZeroReg = Subtarget->isGP64bit() ? Mips::ZERO_64 : Mips::ZERO; 143 TmpInst0.addOperand(MCOperand::createReg(ZeroReg)); 144 } 145 146 lowerOperand(MI->getOperand(0), MCOp); 147 TmpInst0.addOperand(MCOp); 148 149 EmitToStreamer(OutStreamer, TmpInst0); 150 } 151 152 // If there is an MO_JALR operand, insert: 153 // 154 // .reloc tmplabel, R_{MICRO}MIPS_JALR, symbol 155 // tmplabel: 156 // 157 // This is an optimization hint for the linker which may then replace 158 // an indirect call with a direct branch. 159 static void emitDirectiveRelocJalr(const MachineInstr &MI, 160 MCContext &OutContext, 161 TargetMachine &TM, 162 MCStreamer &OutStreamer, 163 const MipsSubtarget &Subtarget) { 164 for (unsigned int I = MI.getDesc().getNumOperands(), E = MI.getNumOperands(); 165 I < E; ++I) { 166 MachineOperand MO = MI.getOperand(I); 167 if (MO.isMCSymbol() && (MO.getTargetFlags() & MipsII::MO_JALR)) { 168 MCSymbol *Callee = MO.getMCSymbol(); 169 if (Callee && !Callee->getName().empty()) { 170 MCSymbol *OffsetLabel = OutContext.createTempSymbol(); 171 const MCExpr *OffsetExpr = 172 MCSymbolRefExpr::create(OffsetLabel, OutContext); 173 const MCExpr *CaleeExpr = 174 MCSymbolRefExpr::create(Callee, OutContext); 175 OutStreamer.EmitRelocDirective 176 (*OffsetExpr, 177 Subtarget.inMicroMipsMode() ? "R_MICROMIPS_JALR" : "R_MIPS_JALR", 178 CaleeExpr, SMLoc(), *TM.getMCSubtargetInfo()); 179 OutStreamer.EmitLabel(OffsetLabel); 180 return; 181 } 182 } 183 } 184 } 185 186 void MipsAsmPrinter::EmitInstruction(const MachineInstr *MI) { 187 MipsTargetStreamer &TS = getTargetStreamer(); 188 unsigned Opc = MI->getOpcode(); 189 TS.forbidModuleDirective(); 190 191 if (MI->isDebugValue()) { 192 SmallString<128> Str; 193 raw_svector_ostream OS(Str); 194 195 PrintDebugValueComment(MI, OS); 196 return; 197 } 198 if (MI->isDebugLabel()) 199 return; 200 201 // If we just ended a constant pool, mark it as such. 202 if (InConstantPool && Opc != Mips::CONSTPOOL_ENTRY) { 203 OutStreamer->EmitDataRegion(MCDR_DataRegionEnd); 204 InConstantPool = false; 205 } 206 if (Opc == Mips::CONSTPOOL_ENTRY) { 207 // CONSTPOOL_ENTRY - This instruction represents a floating 208 // constant pool in the function. The first operand is the ID# 209 // for this instruction, the second is the index into the 210 // MachineConstantPool that this is, the third is the size in 211 // bytes of this constant pool entry. 212 // The required alignment is specified on the basic block holding this MI. 213 // 214 unsigned LabelId = (unsigned)MI->getOperand(0).getImm(); 215 unsigned CPIdx = (unsigned)MI->getOperand(1).getIndex(); 216 217 // If this is the first entry of the pool, mark it. 218 if (!InConstantPool) { 219 OutStreamer->EmitDataRegion(MCDR_DataRegion); 220 InConstantPool = true; 221 } 222 223 OutStreamer->EmitLabel(GetCPISymbol(LabelId)); 224 225 const MachineConstantPoolEntry &MCPE = MCP->getConstants()[CPIdx]; 226 if (MCPE.isMachineConstantPoolEntry()) 227 EmitMachineConstantPoolValue(MCPE.Val.MachineCPVal); 228 else 229 EmitGlobalConstant(MF->getDataLayout(), MCPE.Val.ConstVal); 230 return; 231 } 232 233 switch (Opc) { 234 case Mips::PATCHABLE_FUNCTION_ENTER: 235 LowerPATCHABLE_FUNCTION_ENTER(*MI); 236 return; 237 case Mips::PATCHABLE_FUNCTION_EXIT: 238 LowerPATCHABLE_FUNCTION_EXIT(*MI); 239 return; 240 case Mips::PATCHABLE_TAIL_CALL: 241 LowerPATCHABLE_TAIL_CALL(*MI); 242 return; 243 } 244 245 if (EmitJalrReloc && 246 (MI->isReturn() || MI->isCall() || MI->isIndirectBranch())) { 247 emitDirectiveRelocJalr(*MI, OutContext, TM, *OutStreamer, *Subtarget); 248 } 249 250 MachineBasicBlock::const_instr_iterator I = MI->getIterator(); 251 MachineBasicBlock::const_instr_iterator E = MI->getParent()->instr_end(); 252 253 do { 254 // Do any auto-generated pseudo lowerings. 255 if (emitPseudoExpansionLowering(*OutStreamer, &*I)) 256 continue; 257 258 if (I->getOpcode() == Mips::PseudoReturn || 259 I->getOpcode() == Mips::PseudoReturn64 || 260 I->getOpcode() == Mips::PseudoIndirectBranch || 261 I->getOpcode() == Mips::PseudoIndirectBranch64 || 262 I->getOpcode() == Mips::TAILCALLREG || 263 I->getOpcode() == Mips::TAILCALLREG64) { 264 emitPseudoIndirectBranch(*OutStreamer, &*I); 265 continue; 266 } 267 268 // The inMips16Mode() test is not permanent. 269 // Some instructions are marked as pseudo right now which 270 // would make the test fail for the wrong reason but 271 // that will be fixed soon. We need this here because we are 272 // removing another test for this situation downstream in the 273 // callchain. 274 // 275 if (I->isPseudo() && !Subtarget->inMips16Mode() 276 && !isLongBranchPseudo(I->getOpcode())) 277 llvm_unreachable("Pseudo opcode found in EmitInstruction()"); 278 279 MCInst TmpInst0; 280 MCInstLowering.Lower(&*I, TmpInst0); 281 EmitToStreamer(*OutStreamer, TmpInst0); 282 } while ((++I != E) && I->isInsideBundle()); // Delay slot check 283 } 284 285 //===----------------------------------------------------------------------===// 286 // 287 // Mips Asm Directives 288 // 289 // -- Frame directive "frame Stackpointer, Stacksize, RARegister" 290 // Describe the stack frame. 291 // 292 // -- Mask directives "(f)mask bitmask, offset" 293 // Tells the assembler which registers are saved and where. 294 // bitmask - contain a little endian bitset indicating which registers are 295 // saved on function prologue (e.g. with a 0x80000000 mask, the 296 // assembler knows the register 31 (RA) is saved at prologue. 297 // offset - the position before stack pointer subtraction indicating where 298 // the first saved register on prologue is located. (e.g. with a 299 // 300 // Consider the following function prologue: 301 // 302 // .frame $fp,48,$ra 303 // .mask 0xc0000000,-8 304 // addiu $sp, $sp, -48 305 // sw $ra, 40($sp) 306 // sw $fp, 36($sp) 307 // 308 // With a 0xc0000000 mask, the assembler knows the register 31 (RA) and 309 // 30 (FP) are saved at prologue. As the save order on prologue is from 310 // left to right, RA is saved first. A -8 offset means that after the 311 // stack pointer subtration, the first register in the mask (RA) will be 312 // saved at address 48-8=40. 313 // 314 //===----------------------------------------------------------------------===// 315 316 //===----------------------------------------------------------------------===// 317 // Mask directives 318 //===----------------------------------------------------------------------===// 319 320 // Create a bitmask with all callee saved registers for CPU or Floating Point 321 // registers. For CPU registers consider RA, GP and FP for saving if necessary. 322 void MipsAsmPrinter::printSavedRegsBitmask() { 323 // CPU and FPU Saved Registers Bitmasks 324 unsigned CPUBitmask = 0, FPUBitmask = 0; 325 int CPUTopSavedRegOff, FPUTopSavedRegOff; 326 327 // Set the CPU and FPU Bitmasks 328 const MachineFrameInfo &MFI = MF->getFrameInfo(); 329 const TargetRegisterInfo *TRI = MF->getSubtarget().getRegisterInfo(); 330 const std::vector<CalleeSavedInfo> &CSI = MFI.getCalleeSavedInfo(); 331 // size of stack area to which FP callee-saved regs are saved. 332 unsigned CPURegSize = TRI->getRegSizeInBits(Mips::GPR32RegClass) / 8; 333 unsigned FGR32RegSize = TRI->getRegSizeInBits(Mips::FGR32RegClass) / 8; 334 unsigned AFGR64RegSize = TRI->getRegSizeInBits(Mips::AFGR64RegClass) / 8; 335 bool HasAFGR64Reg = false; 336 unsigned CSFPRegsSize = 0; 337 338 for (const auto &I : CSI) { 339 unsigned Reg = I.getReg(); 340 unsigned RegNum = TRI->getEncodingValue(Reg); 341 342 // If it's a floating point register, set the FPU Bitmask. 343 // If it's a general purpose register, set the CPU Bitmask. 344 if (Mips::FGR32RegClass.contains(Reg)) { 345 FPUBitmask |= (1 << RegNum); 346 CSFPRegsSize += FGR32RegSize; 347 } else if (Mips::AFGR64RegClass.contains(Reg)) { 348 FPUBitmask |= (3 << RegNum); 349 CSFPRegsSize += AFGR64RegSize; 350 HasAFGR64Reg = true; 351 } else if (Mips::GPR32RegClass.contains(Reg)) 352 CPUBitmask |= (1 << RegNum); 353 } 354 355 // FP Regs are saved right below where the virtual frame pointer points to. 356 FPUTopSavedRegOff = FPUBitmask ? 357 (HasAFGR64Reg ? -AFGR64RegSize : -FGR32RegSize) : 0; 358 359 // CPU Regs are saved below FP Regs. 360 CPUTopSavedRegOff = CPUBitmask ? -CSFPRegsSize - CPURegSize : 0; 361 362 MipsTargetStreamer &TS = getTargetStreamer(); 363 // Print CPUBitmask 364 TS.emitMask(CPUBitmask, CPUTopSavedRegOff); 365 366 // Print FPUBitmask 367 TS.emitFMask(FPUBitmask, FPUTopSavedRegOff); 368 } 369 370 //===----------------------------------------------------------------------===// 371 // Frame and Set directives 372 //===----------------------------------------------------------------------===// 373 374 /// Frame Directive 375 void MipsAsmPrinter::emitFrameDirective() { 376 const TargetRegisterInfo &RI = *MF->getSubtarget().getRegisterInfo(); 377 378 unsigned stackReg = RI.getFrameRegister(*MF); 379 unsigned returnReg = RI.getRARegister(); 380 unsigned stackSize = MF->getFrameInfo().getStackSize(); 381 382 getTargetStreamer().emitFrame(stackReg, stackSize, returnReg); 383 } 384 385 /// Emit Set directives. 386 const char *MipsAsmPrinter::getCurrentABIString() const { 387 switch (static_cast<MipsTargetMachine &>(TM).getABI().GetEnumValue()) { 388 case MipsABIInfo::ABI::O32: return "abi32"; 389 case MipsABIInfo::ABI::N32: return "abiN32"; 390 case MipsABIInfo::ABI::N64: return "abi64"; 391 default: llvm_unreachable("Unknown Mips ABI"); 392 } 393 } 394 395 void MipsAsmPrinter::EmitFunctionEntryLabel() { 396 MipsTargetStreamer &TS = getTargetStreamer(); 397 398 // NaCl sandboxing requires that indirect call instructions are masked. 399 // This means that function entry points should be bundle-aligned. 400 if (Subtarget->isTargetNaCl()) 401 EmitAlignment(std::max(MF->getAlignment(), MIPS_NACL_BUNDLE_ALIGN)); 402 403 if (Subtarget->inMicroMipsMode()) { 404 TS.emitDirectiveSetMicroMips(); 405 TS.setUsesMicroMips(); 406 TS.updateABIInfo(*Subtarget); 407 } else 408 TS.emitDirectiveSetNoMicroMips(); 409 410 if (Subtarget->inMips16Mode()) 411 TS.emitDirectiveSetMips16(); 412 else 413 TS.emitDirectiveSetNoMips16(); 414 415 TS.emitDirectiveEnt(*CurrentFnSym); 416 OutStreamer->EmitLabel(CurrentFnSym); 417 } 418 419 /// EmitFunctionBodyStart - Targets can override this to emit stuff before 420 /// the first basic block in the function. 421 void MipsAsmPrinter::EmitFunctionBodyStart() { 422 MipsTargetStreamer &TS = getTargetStreamer(); 423 424 MCInstLowering.Initialize(&MF->getContext()); 425 426 bool IsNakedFunction = MF->getFunction().hasFnAttribute(Attribute::Naked); 427 if (!IsNakedFunction) 428 emitFrameDirective(); 429 430 if (!IsNakedFunction) 431 printSavedRegsBitmask(); 432 433 if (!Subtarget->inMips16Mode()) { 434 TS.emitDirectiveSetNoReorder(); 435 TS.emitDirectiveSetNoMacro(); 436 TS.emitDirectiveSetNoAt(); 437 } 438 } 439 440 /// EmitFunctionBodyEnd - Targets can override this to emit stuff after 441 /// the last basic block in the function. 442 void MipsAsmPrinter::EmitFunctionBodyEnd() { 443 MipsTargetStreamer &TS = getTargetStreamer(); 444 445 // There are instruction for this macros, but they must 446 // always be at the function end, and we can't emit and 447 // break with BB logic. 448 if (!Subtarget->inMips16Mode()) { 449 TS.emitDirectiveSetAt(); 450 TS.emitDirectiveSetMacro(); 451 TS.emitDirectiveSetReorder(); 452 } 453 TS.emitDirectiveEnd(CurrentFnSym->getName()); 454 // Make sure to terminate any constant pools that were at the end 455 // of the function. 456 if (!InConstantPool) 457 return; 458 InConstantPool = false; 459 OutStreamer->EmitDataRegion(MCDR_DataRegionEnd); 460 } 461 462 void MipsAsmPrinter::EmitBasicBlockEnd(const MachineBasicBlock &MBB) { 463 AsmPrinter::EmitBasicBlockEnd(MBB); 464 MipsTargetStreamer &TS = getTargetStreamer(); 465 if (MBB.empty()) 466 TS.emitDirectiveInsn(); 467 } 468 469 /// isBlockOnlyReachableByFallthough - Return true if the basic block has 470 /// exactly one predecessor and the control transfer mechanism between 471 /// the predecessor and this block is a fall-through. 472 bool MipsAsmPrinter::isBlockOnlyReachableByFallthrough(const MachineBasicBlock* 473 MBB) const { 474 // The predecessor has to be immediately before this block. 475 const MachineBasicBlock *Pred = *MBB->pred_begin(); 476 477 // If the predecessor is a switch statement, assume a jump table 478 // implementation, so it is not a fall through. 479 if (const BasicBlock *bb = Pred->getBasicBlock()) 480 if (isa<SwitchInst>(bb->getTerminator())) 481 return false; 482 483 // If this is a landing pad, it isn't a fall through. If it has no preds, 484 // then nothing falls through to it. 485 if (MBB->isEHPad() || MBB->pred_empty()) 486 return false; 487 488 // If there isn't exactly one predecessor, it can't be a fall through. 489 MachineBasicBlock::const_pred_iterator PI = MBB->pred_begin(), PI2 = PI; 490 ++PI2; 491 492 if (PI2 != MBB->pred_end()) 493 return false; 494 495 // The predecessor has to be immediately before this block. 496 if (!Pred->isLayoutSuccessor(MBB)) 497 return false; 498 499 // If the block is completely empty, then it definitely does fall through. 500 if (Pred->empty()) 501 return true; 502 503 // Otherwise, check the last instruction. 504 // Check if the last terminator is an unconditional branch. 505 MachineBasicBlock::const_iterator I = Pred->end(); 506 while (I != Pred->begin() && !(--I)->isTerminator()) ; 507 508 return !I->isBarrier(); 509 } 510 511 // Print out an operand for an inline asm expression. 512 bool MipsAsmPrinter::PrintAsmOperand(const MachineInstr *MI, unsigned OpNum, 513 unsigned AsmVariant, const char *ExtraCode, 514 raw_ostream &O) { 515 // Does this asm operand have a single letter operand modifier? 516 if (ExtraCode && ExtraCode[0]) { 517 if (ExtraCode[1] != 0) return true; // Unknown modifier. 518 519 const MachineOperand &MO = MI->getOperand(OpNum); 520 switch (ExtraCode[0]) { 521 default: 522 // See if this is a generic print operand 523 return AsmPrinter::PrintAsmOperand(MI,OpNum,AsmVariant,ExtraCode,O); 524 case 'X': // hex const int 525 if ((MO.getType()) != MachineOperand::MO_Immediate) 526 return true; 527 O << "0x" << Twine::utohexstr(MO.getImm()); 528 return false; 529 case 'x': // hex const int (low 16 bits) 530 if ((MO.getType()) != MachineOperand::MO_Immediate) 531 return true; 532 O << "0x" << Twine::utohexstr(MO.getImm() & 0xffff); 533 return false; 534 case 'd': // decimal const int 535 if ((MO.getType()) != MachineOperand::MO_Immediate) 536 return true; 537 O << MO.getImm(); 538 return false; 539 case 'm': // decimal const int minus 1 540 if ((MO.getType()) != MachineOperand::MO_Immediate) 541 return true; 542 O << MO.getImm() - 1; 543 return false; 544 case 'y': // exact log2 545 if ((MO.getType()) != MachineOperand::MO_Immediate) 546 return true; 547 if (!isPowerOf2_64(MO.getImm())) 548 return true; 549 O << Log2_64(MO.getImm()); 550 return false; 551 case 'z': 552 // $0 if zero, regular printing otherwise 553 if (MO.getType() == MachineOperand::MO_Immediate && MO.getImm() == 0) { 554 O << "$0"; 555 return false; 556 } 557 // If not, call printOperand as normal. 558 break; 559 case 'D': // Second part of a double word register operand 560 case 'L': // Low order register of a double word register operand 561 case 'M': // High order register of a double word register operand 562 { 563 if (OpNum == 0) 564 return true; 565 const MachineOperand &FlagsOP = MI->getOperand(OpNum - 1); 566 if (!FlagsOP.isImm()) 567 return true; 568 unsigned Flags = FlagsOP.getImm(); 569 unsigned NumVals = InlineAsm::getNumOperandRegisters(Flags); 570 // Number of registers represented by this operand. We are looking 571 // for 2 for 32 bit mode and 1 for 64 bit mode. 572 if (NumVals != 2) { 573 if (Subtarget->isGP64bit() && NumVals == 1 && MO.isReg()) { 574 unsigned Reg = MO.getReg(); 575 O << '$' << MipsInstPrinter::getRegisterName(Reg); 576 return false; 577 } 578 return true; 579 } 580 581 unsigned RegOp = OpNum; 582 if (!Subtarget->isGP64bit()){ 583 // Endianness reverses which register holds the high or low value 584 // between M and L. 585 switch(ExtraCode[0]) { 586 case 'M': 587 RegOp = (Subtarget->isLittle()) ? OpNum + 1 : OpNum; 588 break; 589 case 'L': 590 RegOp = (Subtarget->isLittle()) ? OpNum : OpNum + 1; 591 break; 592 case 'D': // Always the second part 593 RegOp = OpNum + 1; 594 } 595 if (RegOp >= MI->getNumOperands()) 596 return true; 597 const MachineOperand &MO = MI->getOperand(RegOp); 598 if (!MO.isReg()) 599 return true; 600 unsigned Reg = MO.getReg(); 601 O << '$' << MipsInstPrinter::getRegisterName(Reg); 602 return false; 603 } 604 break; 605 } 606 case 'w': 607 // Print MSA registers for the 'f' constraint 608 // In LLVM, the 'w' modifier doesn't need to do anything. 609 // We can just call printOperand as normal. 610 break; 611 } 612 } 613 614 printOperand(MI, OpNum, O); 615 return false; 616 } 617 618 bool MipsAsmPrinter::PrintAsmMemoryOperand(const MachineInstr *MI, 619 unsigned OpNum, unsigned AsmVariant, 620 const char *ExtraCode, 621 raw_ostream &O) { 622 assert(OpNum + 1 < MI->getNumOperands() && "Insufficient operands"); 623 const MachineOperand &BaseMO = MI->getOperand(OpNum); 624 const MachineOperand &OffsetMO = MI->getOperand(OpNum + 1); 625 assert(BaseMO.isReg() && "Unexpected base pointer for inline asm memory operand."); 626 assert(OffsetMO.isImm() && "Unexpected offset for inline asm memory operand."); 627 int Offset = OffsetMO.getImm(); 628 629 // Currently we are expecting either no ExtraCode or 'D','M','L'. 630 if (ExtraCode) { 631 switch (ExtraCode[0]) { 632 case 'D': 633 Offset += 4; 634 break; 635 case 'M': 636 if (Subtarget->isLittle()) 637 Offset += 4; 638 break; 639 case 'L': 640 if (!Subtarget->isLittle()) 641 Offset += 4; 642 break; 643 default: 644 return true; // Unknown modifier. 645 } 646 } 647 648 O << Offset << "($" << MipsInstPrinter::getRegisterName(BaseMO.getReg()) 649 << ")"; 650 651 return false; 652 } 653 654 void MipsAsmPrinter::printOperand(const MachineInstr *MI, int opNum, 655 raw_ostream &O) { 656 const MachineOperand &MO = MI->getOperand(opNum); 657 bool closeP = false; 658 659 if (MO.getTargetFlags()) 660 closeP = true; 661 662 switch(MO.getTargetFlags()) { 663 case MipsII::MO_GPREL: O << "%gp_rel("; break; 664 case MipsII::MO_GOT_CALL: O << "%call16("; break; 665 case MipsII::MO_GOT: O << "%got("; break; 666 case MipsII::MO_ABS_HI: O << "%hi("; break; 667 case MipsII::MO_ABS_LO: O << "%lo("; break; 668 case MipsII::MO_HIGHER: O << "%higher("; break; 669 case MipsII::MO_HIGHEST: O << "%highest(("; break; 670 case MipsII::MO_TLSGD: O << "%tlsgd("; break; 671 case MipsII::MO_GOTTPREL: O << "%gottprel("; break; 672 case MipsII::MO_TPREL_HI: O << "%tprel_hi("; break; 673 case MipsII::MO_TPREL_LO: O << "%tprel_lo("; break; 674 case MipsII::MO_GPOFF_HI: O << "%hi(%neg(%gp_rel("; break; 675 case MipsII::MO_GPOFF_LO: O << "%lo(%neg(%gp_rel("; break; 676 case MipsII::MO_GOT_DISP: O << "%got_disp("; break; 677 case MipsII::MO_GOT_PAGE: O << "%got_page("; break; 678 case MipsII::MO_GOT_OFST: O << "%got_ofst("; break; 679 } 680 681 switch (MO.getType()) { 682 case MachineOperand::MO_Register: 683 O << '$' 684 << StringRef(MipsInstPrinter::getRegisterName(MO.getReg())).lower(); 685 break; 686 687 case MachineOperand::MO_Immediate: 688 O << MO.getImm(); 689 break; 690 691 case MachineOperand::MO_MachineBasicBlock: 692 MO.getMBB()->getSymbol()->print(O, MAI); 693 return; 694 695 case MachineOperand::MO_GlobalAddress: 696 getSymbol(MO.getGlobal())->print(O, MAI); 697 break; 698 699 case MachineOperand::MO_BlockAddress: { 700 MCSymbol *BA = GetBlockAddressSymbol(MO.getBlockAddress()); 701 O << BA->getName(); 702 break; 703 } 704 705 case MachineOperand::MO_ConstantPoolIndex: 706 O << getDataLayout().getPrivateGlobalPrefix() << "CPI" 707 << getFunctionNumber() << "_" << MO.getIndex(); 708 if (MO.getOffset()) 709 O << "+" << MO.getOffset(); 710 break; 711 712 default: 713 llvm_unreachable("<unknown operand type>"); 714 } 715 716 if (closeP) O << ")"; 717 } 718 719 void MipsAsmPrinter:: 720 printMemOperand(const MachineInstr *MI, int opNum, raw_ostream &O) { 721 // Load/Store memory operands -- imm($reg) 722 // If PIC target the target is loaded as the 723 // pattern lw $25,%call16($28) 724 725 // opNum can be invalid if instruction has reglist as operand. 726 // MemOperand is always last operand of instruction (base + offset). 727 switch (MI->getOpcode()) { 728 default: 729 break; 730 case Mips::SWM32_MM: 731 case Mips::LWM32_MM: 732 opNum = MI->getNumOperands() - 2; 733 break; 734 } 735 736 printOperand(MI, opNum+1, O); 737 O << "("; 738 printOperand(MI, opNum, O); 739 O << ")"; 740 } 741 742 void MipsAsmPrinter:: 743 printMemOperandEA(const MachineInstr *MI, int opNum, raw_ostream &O) { 744 // when using stack locations for not load/store instructions 745 // print the same way as all normal 3 operand instructions. 746 printOperand(MI, opNum, O); 747 O << ", "; 748 printOperand(MI, opNum+1, O); 749 } 750 751 void MipsAsmPrinter:: 752 printFCCOperand(const MachineInstr *MI, int opNum, raw_ostream &O, 753 const char *Modifier) { 754 const MachineOperand &MO = MI->getOperand(opNum); 755 O << Mips::MipsFCCToString((Mips::CondCode)MO.getImm()); 756 } 757 758 void MipsAsmPrinter:: 759 printRegisterList(const MachineInstr *MI, int opNum, raw_ostream &O) { 760 for (int i = opNum, e = MI->getNumOperands(); i != e; ++i) { 761 if (i != opNum) O << ", "; 762 printOperand(MI, i, O); 763 } 764 } 765 766 void MipsAsmPrinter::EmitStartOfAsmFile(Module &M) { 767 MipsTargetStreamer &TS = getTargetStreamer(); 768 769 // MipsTargetStreamer has an initialization order problem when emitting an 770 // object file directly (see MipsTargetELFStreamer for full details). Work 771 // around it by re-initializing the PIC state here. 772 TS.setPic(OutContext.getObjectFileInfo()->isPositionIndependent()); 773 774 // Compute MIPS architecture attributes based on the default subtarget 775 // that we'd have constructed. Module level directives aren't LTO 776 // clean anyhow. 777 // FIXME: For ifunc related functions we could iterate over and look 778 // for a feature string that doesn't match the default one. 779 const Triple &TT = TM.getTargetTriple(); 780 StringRef CPU = MIPS_MC::selectMipsCPU(TT, TM.getTargetCPU()); 781 StringRef FS = TM.getTargetFeatureString(); 782 const MipsTargetMachine &MTM = static_cast<const MipsTargetMachine &>(TM); 783 const MipsSubtarget STI(TT, CPU, FS, MTM.isLittleEndian(), MTM, 0); 784 785 bool IsABICalls = STI.isABICalls(); 786 const MipsABIInfo &ABI = MTM.getABI(); 787 if (IsABICalls) { 788 TS.emitDirectiveAbiCalls(); 789 // FIXME: This condition should be a lot more complicated that it is here. 790 // Ideally it should test for properties of the ABI and not the ABI 791 // itself. 792 // For the moment, I'm only correcting enough to make MIPS-IV work. 793 if (!isPositionIndependent() && STI.hasSym32()) 794 TS.emitDirectiveOptionPic0(); 795 } 796 797 // Tell the assembler which ABI we are using 798 std::string SectionName = std::string(".mdebug.") + getCurrentABIString(); 799 OutStreamer->SwitchSection( 800 OutContext.getELFSection(SectionName, ELF::SHT_PROGBITS, 0)); 801 802 // NaN: At the moment we only support: 803 // 1. .nan legacy (default) 804 // 2. .nan 2008 805 STI.isNaN2008() ? TS.emitDirectiveNaN2008() 806 : TS.emitDirectiveNaNLegacy(); 807 808 // TODO: handle O64 ABI 809 810 TS.updateABIInfo(STI); 811 812 // We should always emit a '.module fp=...' but binutils 2.24 does not accept 813 // it. We therefore emit it when it contradicts the ABI defaults (-mfpxx or 814 // -mfp64) and omit it otherwise. 815 if ((ABI.IsO32() && (STI.isABI_FPXX() || STI.isFP64bit())) || 816 STI.useSoftFloat()) 817 TS.emitDirectiveModuleFP(); 818 819 // We should always emit a '.module [no]oddspreg' but binutils 2.24 does not 820 // accept it. We therefore emit it when it contradicts the default or an 821 // option has changed the default (i.e. FPXX) and omit it otherwise. 822 if (ABI.IsO32() && (!STI.useOddSPReg() || STI.isABI_FPXX())) 823 TS.emitDirectiveModuleOddSPReg(); 824 } 825 826 void MipsAsmPrinter::emitInlineAsmStart() const { 827 MipsTargetStreamer &TS = getTargetStreamer(); 828 829 // GCC's choice of assembler options for inline assembly code ('at', 'macro' 830 // and 'reorder') is different from LLVM's choice for generated code ('noat', 831 // 'nomacro' and 'noreorder'). 832 // In order to maintain compatibility with inline assembly code which depends 833 // on GCC's assembler options being used, we have to switch to those options 834 // for the duration of the inline assembly block and then switch back. 835 TS.emitDirectiveSetPush(); 836 TS.emitDirectiveSetAt(); 837 TS.emitDirectiveSetMacro(); 838 TS.emitDirectiveSetReorder(); 839 OutStreamer->AddBlankLine(); 840 } 841 842 void MipsAsmPrinter::emitInlineAsmEnd(const MCSubtargetInfo &StartInfo, 843 const MCSubtargetInfo *EndInfo) const { 844 OutStreamer->AddBlankLine(); 845 getTargetStreamer().emitDirectiveSetPop(); 846 } 847 848 void MipsAsmPrinter::EmitJal(const MCSubtargetInfo &STI, MCSymbol *Symbol) { 849 MCInst I; 850 I.setOpcode(Mips::JAL); 851 I.addOperand( 852 MCOperand::createExpr(MCSymbolRefExpr::create(Symbol, OutContext))); 853 OutStreamer->EmitInstruction(I, STI); 854 } 855 856 void MipsAsmPrinter::EmitInstrReg(const MCSubtargetInfo &STI, unsigned Opcode, 857 unsigned Reg) { 858 MCInst I; 859 I.setOpcode(Opcode); 860 I.addOperand(MCOperand::createReg(Reg)); 861 OutStreamer->EmitInstruction(I, STI); 862 } 863 864 void MipsAsmPrinter::EmitInstrRegReg(const MCSubtargetInfo &STI, 865 unsigned Opcode, unsigned Reg1, 866 unsigned Reg2) { 867 MCInst I; 868 // 869 // Because of the current td files for Mips32, the operands for MTC1 870 // appear backwards from their normal assembly order. It's not a trivial 871 // change to fix this in the td file so we adjust for it here. 872 // 873 if (Opcode == Mips::MTC1) { 874 unsigned Temp = Reg1; 875 Reg1 = Reg2; 876 Reg2 = Temp; 877 } 878 I.setOpcode(Opcode); 879 I.addOperand(MCOperand::createReg(Reg1)); 880 I.addOperand(MCOperand::createReg(Reg2)); 881 OutStreamer->EmitInstruction(I, STI); 882 } 883 884 void MipsAsmPrinter::EmitInstrRegRegReg(const MCSubtargetInfo &STI, 885 unsigned Opcode, unsigned Reg1, 886 unsigned Reg2, unsigned Reg3) { 887 MCInst I; 888 I.setOpcode(Opcode); 889 I.addOperand(MCOperand::createReg(Reg1)); 890 I.addOperand(MCOperand::createReg(Reg2)); 891 I.addOperand(MCOperand::createReg(Reg3)); 892 OutStreamer->EmitInstruction(I, STI); 893 } 894 895 void MipsAsmPrinter::EmitMovFPIntPair(const MCSubtargetInfo &STI, 896 unsigned MovOpc, unsigned Reg1, 897 unsigned Reg2, unsigned FPReg1, 898 unsigned FPReg2, bool LE) { 899 if (!LE) { 900 unsigned temp = Reg1; 901 Reg1 = Reg2; 902 Reg2 = temp; 903 } 904 EmitInstrRegReg(STI, MovOpc, Reg1, FPReg1); 905 EmitInstrRegReg(STI, MovOpc, Reg2, FPReg2); 906 } 907 908 void MipsAsmPrinter::EmitSwapFPIntParams(const MCSubtargetInfo &STI, 909 Mips16HardFloatInfo::FPParamVariant PV, 910 bool LE, bool ToFP) { 911 using namespace Mips16HardFloatInfo; 912 913 unsigned MovOpc = ToFP ? Mips::MTC1 : Mips::MFC1; 914 switch (PV) { 915 case FSig: 916 EmitInstrRegReg(STI, MovOpc, Mips::A0, Mips::F12); 917 break; 918 case FFSig: 919 EmitMovFPIntPair(STI, MovOpc, Mips::A0, Mips::A1, Mips::F12, Mips::F14, LE); 920 break; 921 case FDSig: 922 EmitInstrRegReg(STI, MovOpc, Mips::A0, Mips::F12); 923 EmitMovFPIntPair(STI, MovOpc, Mips::A2, Mips::A3, Mips::F14, Mips::F15, LE); 924 break; 925 case DSig: 926 EmitMovFPIntPair(STI, MovOpc, Mips::A0, Mips::A1, Mips::F12, Mips::F13, LE); 927 break; 928 case DDSig: 929 EmitMovFPIntPair(STI, MovOpc, Mips::A0, Mips::A1, Mips::F12, Mips::F13, LE); 930 EmitMovFPIntPair(STI, MovOpc, Mips::A2, Mips::A3, Mips::F14, Mips::F15, LE); 931 break; 932 case DFSig: 933 EmitMovFPIntPair(STI, MovOpc, Mips::A0, Mips::A1, Mips::F12, Mips::F13, LE); 934 EmitInstrRegReg(STI, MovOpc, Mips::A2, Mips::F14); 935 break; 936 case NoSig: 937 return; 938 } 939 } 940 941 void MipsAsmPrinter::EmitSwapFPIntRetval( 942 const MCSubtargetInfo &STI, Mips16HardFloatInfo::FPReturnVariant RV, 943 bool LE) { 944 using namespace Mips16HardFloatInfo; 945 946 unsigned MovOpc = Mips::MFC1; 947 switch (RV) { 948 case FRet: 949 EmitInstrRegReg(STI, MovOpc, Mips::V0, Mips::F0); 950 break; 951 case DRet: 952 EmitMovFPIntPair(STI, MovOpc, Mips::V0, Mips::V1, Mips::F0, Mips::F1, LE); 953 break; 954 case CFRet: 955 EmitMovFPIntPair(STI, MovOpc, Mips::V0, Mips::V1, Mips::F0, Mips::F1, LE); 956 break; 957 case CDRet: 958 EmitMovFPIntPair(STI, MovOpc, Mips::V0, Mips::V1, Mips::F0, Mips::F1, LE); 959 EmitMovFPIntPair(STI, MovOpc, Mips::A0, Mips::A1, Mips::F2, Mips::F3, LE); 960 break; 961 case NoFPRet: 962 break; 963 } 964 } 965 966 void MipsAsmPrinter::EmitFPCallStub( 967 const char *Symbol, const Mips16HardFloatInfo::FuncSignature *Signature) { 968 using namespace Mips16HardFloatInfo; 969 970 MCSymbol *MSymbol = OutContext.getOrCreateSymbol(StringRef(Symbol)); 971 bool LE = getDataLayout().isLittleEndian(); 972 // Construct a local MCSubtargetInfo here. 973 // This is because the MachineFunction won't exist (but have not yet been 974 // freed) and since we're at the global level we can use the default 975 // constructed subtarget. 976 std::unique_ptr<MCSubtargetInfo> STI(TM.getTarget().createMCSubtargetInfo( 977 TM.getTargetTriple().str(), TM.getTargetCPU(), 978 TM.getTargetFeatureString())); 979 980 // 981 // .global xxxx 982 // 983 OutStreamer->EmitSymbolAttribute(MSymbol, MCSA_Global); 984 const char *RetType; 985 // 986 // make the comment field identifying the return and parameter 987 // types of the floating point stub 988 // # Stub function to call rettype xxxx (params) 989 // 990 switch (Signature->RetSig) { 991 case FRet: 992 RetType = "float"; 993 break; 994 case DRet: 995 RetType = "double"; 996 break; 997 case CFRet: 998 RetType = "complex"; 999 break; 1000 case CDRet: 1001 RetType = "double complex"; 1002 break; 1003 case NoFPRet: 1004 RetType = ""; 1005 break; 1006 } 1007 const char *Parms; 1008 switch (Signature->ParamSig) { 1009 case FSig: 1010 Parms = "float"; 1011 break; 1012 case FFSig: 1013 Parms = "float, float"; 1014 break; 1015 case FDSig: 1016 Parms = "float, double"; 1017 break; 1018 case DSig: 1019 Parms = "double"; 1020 break; 1021 case DDSig: 1022 Parms = "double, double"; 1023 break; 1024 case DFSig: 1025 Parms = "double, float"; 1026 break; 1027 case NoSig: 1028 Parms = ""; 1029 break; 1030 } 1031 OutStreamer->AddComment("\t# Stub function to call " + Twine(RetType) + " " + 1032 Twine(Symbol) + " (" + Twine(Parms) + ")"); 1033 // 1034 // probably not necessary but we save and restore the current section state 1035 // 1036 OutStreamer->PushSection(); 1037 // 1038 // .section mips16.call.fpxxxx,"ax",@progbits 1039 // 1040 MCSectionELF *M = OutContext.getELFSection( 1041 ".mips16.call.fp." + std::string(Symbol), ELF::SHT_PROGBITS, 1042 ELF::SHF_ALLOC | ELF::SHF_EXECINSTR); 1043 OutStreamer->SwitchSection(M, nullptr); 1044 // 1045 // .align 2 1046 // 1047 OutStreamer->EmitValueToAlignment(4); 1048 MipsTargetStreamer &TS = getTargetStreamer(); 1049 // 1050 // .set nomips16 1051 // .set nomicromips 1052 // 1053 TS.emitDirectiveSetNoMips16(); 1054 TS.emitDirectiveSetNoMicroMips(); 1055 // 1056 // .ent __call_stub_fp_xxxx 1057 // .type __call_stub_fp_xxxx,@function 1058 // __call_stub_fp_xxxx: 1059 // 1060 std::string x = "__call_stub_fp_" + std::string(Symbol); 1061 MCSymbolELF *Stub = 1062 cast<MCSymbolELF>(OutContext.getOrCreateSymbol(StringRef(x))); 1063 TS.emitDirectiveEnt(*Stub); 1064 MCSymbol *MType = 1065 OutContext.getOrCreateSymbol("__call_stub_fp_" + Twine(Symbol)); 1066 OutStreamer->EmitSymbolAttribute(MType, MCSA_ELF_TypeFunction); 1067 OutStreamer->EmitLabel(Stub); 1068 1069 // Only handle non-pic for now. 1070 assert(!isPositionIndependent() && 1071 "should not be here if we are compiling pic"); 1072 TS.emitDirectiveSetReorder(); 1073 // 1074 // We need to add a MipsMCExpr class to MCTargetDesc to fully implement 1075 // stubs without raw text but this current patch is for compiler generated 1076 // functions and they all return some value. 1077 // The calling sequence for non pic is different in that case and we need 1078 // to implement %lo and %hi in order to handle the case of no return value 1079 // See the corresponding method in Mips16HardFloat for details. 1080 // 1081 // mov the return address to S2. 1082 // we have no stack space to store it and we are about to make another call. 1083 // We need to make sure that the enclosing function knows to save S2 1084 // This should have already been handled. 1085 // 1086 // Mov $18, $31 1087 1088 EmitInstrRegRegReg(*STI, Mips::OR, Mips::S2, Mips::RA, Mips::ZERO); 1089 1090 EmitSwapFPIntParams(*STI, Signature->ParamSig, LE, true); 1091 1092 // Jal xxxx 1093 // 1094 EmitJal(*STI, MSymbol); 1095 1096 // fix return values 1097 EmitSwapFPIntRetval(*STI, Signature->RetSig, LE); 1098 // 1099 // do the return 1100 // if (Signature->RetSig == NoFPRet) 1101 // llvm_unreachable("should not be any stubs here with no return value"); 1102 // else 1103 EmitInstrReg(*STI, Mips::JR, Mips::S2); 1104 1105 MCSymbol *Tmp = OutContext.createTempSymbol(); 1106 OutStreamer->EmitLabel(Tmp); 1107 const MCSymbolRefExpr *E = MCSymbolRefExpr::create(Stub, OutContext); 1108 const MCSymbolRefExpr *T = MCSymbolRefExpr::create(Tmp, OutContext); 1109 const MCExpr *T_min_E = MCBinaryExpr::createSub(T, E, OutContext); 1110 OutStreamer->emitELFSize(Stub, T_min_E); 1111 TS.emitDirectiveEnd(x); 1112 OutStreamer->PopSection(); 1113 } 1114 1115 void MipsAsmPrinter::EmitEndOfAsmFile(Module &M) { 1116 // Emit needed stubs 1117 // 1118 for (std::map< 1119 const char *, 1120 const Mips16HardFloatInfo::FuncSignature *>::const_iterator 1121 it = StubsNeeded.begin(); 1122 it != StubsNeeded.end(); ++it) { 1123 const char *Symbol = it->first; 1124 const Mips16HardFloatInfo::FuncSignature *Signature = it->second; 1125 EmitFPCallStub(Symbol, Signature); 1126 } 1127 // return to the text section 1128 OutStreamer->SwitchSection(OutContext.getObjectFileInfo()->getTextSection()); 1129 } 1130 1131 void MipsAsmPrinter::EmitSled(const MachineInstr &MI, SledKind Kind) { 1132 const uint8_t NoopsInSledCount = Subtarget->isGP64bit() ? 15 : 11; 1133 // For mips32 we want to emit the following pattern: 1134 // 1135 // .Lxray_sled_N: 1136 // ALIGN 1137 // B .tmpN 1138 // 11 NOP instructions (44 bytes) 1139 // ADDIU T9, T9, 52 1140 // .tmpN 1141 // 1142 // We need the 44 bytes (11 instructions) because at runtime, we'd 1143 // be patching over the full 48 bytes (12 instructions) with the following 1144 // pattern: 1145 // 1146 // ADDIU SP, SP, -8 1147 // NOP 1148 // SW RA, 4(SP) 1149 // SW T9, 0(SP) 1150 // LUI T9, %hi(__xray_FunctionEntry/Exit) 1151 // ORI T9, T9, %lo(__xray_FunctionEntry/Exit) 1152 // LUI T0, %hi(function_id) 1153 // JALR T9 1154 // ORI T0, T0, %lo(function_id) 1155 // LW T9, 0(SP) 1156 // LW RA, 4(SP) 1157 // ADDIU SP, SP, 8 1158 // 1159 // We add 52 bytes to t9 because we want to adjust the function pointer to 1160 // the actual start of function i.e. the address just after the noop sled. 1161 // We do this because gp displacement relocation is emitted at the start of 1162 // of the function i.e after the nop sled and to correctly calculate the 1163 // global offset table address, t9 must hold the address of the instruction 1164 // containing the gp displacement relocation. 1165 // FIXME: Is this correct for the static relocation model? 1166 // 1167 // For mips64 we want to emit the following pattern: 1168 // 1169 // .Lxray_sled_N: 1170 // ALIGN 1171 // B .tmpN 1172 // 15 NOP instructions (60 bytes) 1173 // .tmpN 1174 // 1175 // We need the 60 bytes (15 instructions) because at runtime, we'd 1176 // be patching over the full 64 bytes (16 instructions) with the following 1177 // pattern: 1178 // 1179 // DADDIU SP, SP, -16 1180 // NOP 1181 // SD RA, 8(SP) 1182 // SD T9, 0(SP) 1183 // LUI T9, %highest(__xray_FunctionEntry/Exit) 1184 // ORI T9, T9, %higher(__xray_FunctionEntry/Exit) 1185 // DSLL T9, T9, 16 1186 // ORI T9, T9, %hi(__xray_FunctionEntry/Exit) 1187 // DSLL T9, T9, 16 1188 // ORI T9, T9, %lo(__xray_FunctionEntry/Exit) 1189 // LUI T0, %hi(function_id) 1190 // JALR T9 1191 // ADDIU T0, T0, %lo(function_id) 1192 // LD T9, 0(SP) 1193 // LD RA, 8(SP) 1194 // DADDIU SP, SP, 16 1195 // 1196 OutStreamer->EmitCodeAlignment(4); 1197 auto CurSled = OutContext.createTempSymbol("xray_sled_", true); 1198 OutStreamer->EmitLabel(CurSled); 1199 auto Target = OutContext.createTempSymbol(); 1200 1201 // Emit "B .tmpN" instruction, which jumps over the nop sled to the actual 1202 // start of function 1203 const MCExpr *TargetExpr = MCSymbolRefExpr::create( 1204 Target, MCSymbolRefExpr::VariantKind::VK_None, OutContext); 1205 EmitToStreamer(*OutStreamer, MCInstBuilder(Mips::BEQ) 1206 .addReg(Mips::ZERO) 1207 .addReg(Mips::ZERO) 1208 .addExpr(TargetExpr)); 1209 1210 for (int8_t I = 0; I < NoopsInSledCount; I++) 1211 EmitToStreamer(*OutStreamer, MCInstBuilder(Mips::SLL) 1212 .addReg(Mips::ZERO) 1213 .addReg(Mips::ZERO) 1214 .addImm(0)); 1215 1216 OutStreamer->EmitLabel(Target); 1217 1218 if (!Subtarget->isGP64bit()) { 1219 EmitToStreamer(*OutStreamer, 1220 MCInstBuilder(Mips::ADDiu) 1221 .addReg(Mips::T9) 1222 .addReg(Mips::T9) 1223 .addImm(0x34)); 1224 } 1225 1226 recordSled(CurSled, MI, Kind); 1227 } 1228 1229 void MipsAsmPrinter::LowerPATCHABLE_FUNCTION_ENTER(const MachineInstr &MI) { 1230 EmitSled(MI, SledKind::FUNCTION_ENTER); 1231 } 1232 1233 void MipsAsmPrinter::LowerPATCHABLE_FUNCTION_EXIT(const MachineInstr &MI) { 1234 EmitSled(MI, SledKind::FUNCTION_EXIT); 1235 } 1236 1237 void MipsAsmPrinter::LowerPATCHABLE_TAIL_CALL(const MachineInstr &MI) { 1238 EmitSled(MI, SledKind::TAIL_CALL); 1239 } 1240 1241 void MipsAsmPrinter::PrintDebugValueComment(const MachineInstr *MI, 1242 raw_ostream &OS) { 1243 // TODO: implement 1244 } 1245 1246 // Emit .dtprelword or .dtpreldword directive 1247 // and value for debug thread local expression. 1248 void MipsAsmPrinter::EmitDebugValue(const MCExpr *Value, unsigned Size) const { 1249 if (auto *MipsExpr = dyn_cast<MipsMCExpr>(Value)) { 1250 if (MipsExpr && MipsExpr->getKind() == MipsMCExpr::MEK_DTPREL) { 1251 switch (Size) { 1252 case 4: 1253 OutStreamer->EmitDTPRel32Value(MipsExpr->getSubExpr()); 1254 break; 1255 case 8: 1256 OutStreamer->EmitDTPRel64Value(MipsExpr->getSubExpr()); 1257 break; 1258 default: 1259 llvm_unreachable("Unexpected size of expression value."); 1260 } 1261 return; 1262 } 1263 } 1264 AsmPrinter::EmitDebugValue(Value, Size); 1265 } 1266 1267 // Align all targets of indirect branches on bundle size. Used only if target 1268 // is NaCl. 1269 void MipsAsmPrinter::NaClAlignIndirectJumpTargets(MachineFunction &MF) { 1270 // Align all blocks that are jumped to through jump table. 1271 if (MachineJumpTableInfo *JtInfo = MF.getJumpTableInfo()) { 1272 const std::vector<MachineJumpTableEntry> &JT = JtInfo->getJumpTables(); 1273 for (unsigned I = 0; I < JT.size(); ++I) { 1274 const std::vector<MachineBasicBlock*> &MBBs = JT[I].MBBs; 1275 1276 for (unsigned J = 0; J < MBBs.size(); ++J) 1277 MBBs[J]->setAlignment(MIPS_NACL_BUNDLE_ALIGN); 1278 } 1279 } 1280 1281 // If basic block address is taken, block can be target of indirect branch. 1282 for (auto &MBB : MF) { 1283 if (MBB.hasAddressTaken()) 1284 MBB.setAlignment(MIPS_NACL_BUNDLE_ALIGN); 1285 } 1286 } 1287 1288 bool MipsAsmPrinter::isLongBranchPseudo(int Opcode) const { 1289 return (Opcode == Mips::LONG_BRANCH_LUi 1290 || Opcode == Mips::LONG_BRANCH_LUi2Op 1291 || Opcode == Mips::LONG_BRANCH_LUi2Op_64 1292 || Opcode == Mips::LONG_BRANCH_ADDiu 1293 || Opcode == Mips::LONG_BRANCH_ADDiu2Op 1294 || Opcode == Mips::LONG_BRANCH_DADDiu 1295 || Opcode == Mips::LONG_BRANCH_DADDiu2Op); 1296 } 1297 1298 // Force static initialization. 1299 extern "C" void LLVMInitializeMipsAsmPrinter() { 1300 RegisterAsmPrinter<MipsAsmPrinter> X(getTheMipsTarget()); 1301 RegisterAsmPrinter<MipsAsmPrinter> Y(getTheMipselTarget()); 1302 RegisterAsmPrinter<MipsAsmPrinter> A(getTheMips64Target()); 1303 RegisterAsmPrinter<MipsAsmPrinter> B(getTheMips64elTarget()); 1304 } 1305