lib/MC/MCExpr.cpp

   1 //===- MCExpr.cpp - Assembly Level Expression Implementation --------------===//
   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 #include "llvm/MC/MCExpr.h"
  10 #include "llvm/ADT/Statistic.h"
  11 #include "llvm/ADT/StringExtras.h"
  12 #include "llvm/ADT/StringSwitch.h"
  13 #include "llvm/Config/llvm-config.h"
  14 #include "llvm/MC/MCAsmBackend.h"
  15 #include "llvm/MC/MCAsmInfo.h"
  16 #include "llvm/MC/MCAsmLayout.h"
  17 #include "llvm/MC/MCAssembler.h"
  18 #include "llvm/MC/MCContext.h"
  19 #include "llvm/MC/MCObjectWriter.h"
  20 #include "llvm/MC/MCSymbol.h"
  21 #include "llvm/MC/MCValue.h"
  22 #include "llvm/Support/Casting.h"
  23 #include "llvm/Support/Compiler.h"
  24 #include "llvm/Support/Debug.h"
  25 #include "llvm/Support/ErrorHandling.h"
  26 #include "llvm/Support/raw_ostream.h"
  27 #include <cassert>
  28 #include <cstdint>
  29
  30 using namespace llvm;
  31
  32 #define DEBUG_TYPE "mcexpr"
  33
  34 namespace {
  35 namespace stats {
  36
  37 STATISTIC(MCExprEvaluate, "Number of MCExpr evaluations");
  38
  39 } // end namespace stats
  40 } // end anonymous namespace
  41
  42 void MCExpr::print(raw_ostream &OS, const MCAsmInfo *MAI, bool InParens) const {
  43   switch (getKind()) {
  44   case MCExpr::Target:
  45     return cast<MCTargetExpr>(this)->printImpl(OS, MAI);
  46   case MCExpr::Constant: {
  47     auto Value = cast<MCConstantExpr>(*this).getValue();
  48     auto PrintInHex = cast<MCConstantExpr>(*this).useHexFormat();
  49     if (PrintInHex)
  50       OS << "0x" << Twine::utohexstr(Value);
  51     else
  52       OS << Value;
  53     return;
  54   }
  55   case MCExpr::SymbolRef: {
  56     const MCSymbolRefExpr &SRE = cast<MCSymbolRefExpr>(*this);
  57     const MCSymbol &Sym = SRE.getSymbol();
  58     // Parenthesize names that start with $ so that they don't look like
  59     // absolute names.
  60     bool UseParens =
  61         !InParens && !Sym.getName().empty() && Sym.getName()[0] == '$';
  62     if (UseParens) {
  63       OS << '(';
  64       Sym.print(OS, MAI);
  65       OS << ')';
  66     } else
  67       Sym.print(OS, MAI);
  68
  69     if (SRE.getKind() != MCSymbolRefExpr::VK_None)
  70       SRE.printVariantKind(OS);
  71
  72     return;
  73   }
  74
  75   case MCExpr::Unary: {
  76     const MCUnaryExpr &UE = cast<MCUnaryExpr>(*this);
  77     switch (UE.getOpcode()) {
  78     case MCUnaryExpr::LNot:  OS << '!'; break;
  79     case MCUnaryExpr::Minus: OS << '-'; break;
  80     case MCUnaryExpr::Not:   OS << '~'; break;
  81     case MCUnaryExpr::Plus:  OS << '+'; break;
  82     }
  83     bool Binary = UE.getSubExpr()->getKind() == MCExpr::Binary;
  84     if (Binary) OS << "(";
  85     UE.getSubExpr()->print(OS, MAI);
  86     if (Binary) OS << ")";
  87     return;
  88   }
  89
  90   case MCExpr::Binary: {
  91     const MCBinaryExpr &BE = cast<MCBinaryExpr>(*this);
  92
  93     // Only print parens around the LHS if it is non-trivial.
  94     if (isa<MCConstantExpr>(BE.getLHS()) || isa<MCSymbolRefExpr>(BE.getLHS())) {
  95       BE.getLHS()->print(OS, MAI);
  96     } else {
  97       OS << '(';
  98       BE.getLHS()->print(OS, MAI);
  99       OS << ')';
 100     }
 101
 102     switch (BE.getOpcode()) {
 103     case MCBinaryExpr::Add:
 104       // Print "X-42" instead of "X+-42".
 105       if (const MCConstantExpr *RHSC = dyn_cast<MCConstantExpr>(BE.getRHS())) {
 106         if (RHSC->getValue() < 0) {
 107           OS << RHSC->getValue();
 108           return;
 109         }
 110       }
 111
 112       OS <<  '+';
 113       break;
 114     case MCBinaryExpr::AShr: OS << ">>"; break;
 115     case MCBinaryExpr::And:  OS <<  '&'; break;
 116     case MCBinaryExpr::Div:  OS <<  '/'; break;
 117     case MCBinaryExpr::EQ:   OS << "=="; break;
 118     case MCBinaryExpr::GT:   OS <<  '>'; break;
 119     case MCBinaryExpr::GTE:  OS << ">="; break;
 120     case MCBinaryExpr::LAnd: OS << "&&"; break;
 121     case MCBinaryExpr::LOr:  OS << "||"; break;
 122     case MCBinaryExpr::LShr: OS << ">>"; break;
 123     case MCBinaryExpr::LT:   OS <<  '<'; break;
 124     case MCBinaryExpr::LTE:  OS << "<="; break;
 125     case MCBinaryExpr::Mod:  OS <<  '%'; break;
 126     case MCBinaryExpr::Mul:  OS <<  '*'; break;
 127     case MCBinaryExpr::NE:   OS << "!="; break;
 128     case MCBinaryExpr::Or:   OS <<  '|'; break;
 129     case MCBinaryExpr::Shl:  OS << "<<"; break;
 130     case MCBinaryExpr::Sub:  OS <<  '-'; break;
 131     case MCBinaryExpr::Xor:  OS <<  '^'; break;
 132     }
 133
 134     // Only print parens around the LHS if it is non-trivial.
 135     if (isa<MCConstantExpr>(BE.getRHS()) || isa<MCSymbolRefExpr>(BE.getRHS())) {
 136       BE.getRHS()->print(OS, MAI);
 137     } else {
 138       OS << '(';
 139       BE.getRHS()->print(OS, MAI);
 140       OS << ')';
 141     }
 142     return;
 143   }
 144   }
 145
 146   llvm_unreachable("Invalid expression kind!");
 147 }
 148
 149 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
 150 LLVM_DUMP_METHOD void MCExpr::dump() const {
 151   dbgs() << *this;
 152   dbgs() << '\n';
 153 }
 154 #endif
 155
 156 /* *** */
 157
 158 const MCBinaryExpr *MCBinaryExpr::create(Opcode Opc, const MCExpr *LHS,
 159                                          const MCExpr *RHS, MCContext &Ctx,
 160                                          SMLoc Loc) {
 161   return new (Ctx) MCBinaryExpr(Opc, LHS, RHS, Loc);
 162 }
 163
 164 const MCUnaryExpr *MCUnaryExpr::create(Opcode Opc, const MCExpr *Expr,
 165                                        MCContext &Ctx, SMLoc Loc) {
 166   return new (Ctx) MCUnaryExpr(Opc, Expr, Loc);
 167 }
 168
 169 const MCConstantExpr *MCConstantExpr::create(int64_t Value, MCContext &Ctx,
 170                                              bool PrintInHex) {
 171   return new (Ctx) MCConstantExpr(Value, PrintInHex);
 172 }
 173
 174 /* *** */
 175
 176 MCSymbolRefExpr::MCSymbolRefExpr(const MCSymbol *Symbol, VariantKind Kind,
 177                                  const MCAsmInfo *MAI, SMLoc Loc)
 178     : MCExpr(MCExpr::SymbolRef, Loc), Kind(Kind),
 179       UseParensForSymbolVariant(MAI->useParensForSymbolVariant()),
 180       HasSubsectionsViaSymbols(MAI->hasSubsectionsViaSymbols()),
 181       Symbol(Symbol) {
 182   assert(Symbol);
 183 }
 184
 185 const MCSymbolRefExpr *MCSymbolRefExpr::create(const MCSymbol *Sym,
 186                                                VariantKind Kind,
 187                                                MCContext &Ctx, SMLoc Loc) {
 188   return new (Ctx) MCSymbolRefExpr(Sym, Kind, Ctx.getAsmInfo(), Loc);
 189 }
 190
 191 const MCSymbolRefExpr *MCSymbolRefExpr::create(StringRef Name, VariantKind Kind,
 192                                                MCContext &Ctx) {
 193   return create(Ctx.getOrCreateSymbol(Name), Kind, Ctx);
 194 }
 195
 196 StringRef MCSymbolRefExpr::getVariantKindName(VariantKind Kind) {
 197   switch (Kind) {
 198   case VK_Invalid: return "<<invalid>>";
 199   case VK_None: return "<<none>>";
 200
 201   case VK_DTPOFF: return "DTPOFF";
 202   case VK_DTPREL: return "DTPREL";
 203   case VK_GOT: return "GOT";
 204   case VK_GOTOFF: return "GOTOFF";
 205   case VK_GOTREL: return "GOTREL";
 206   case VK_GOTPCREL: return "GOTPCREL";
 207   case VK_GOTTPOFF: return "GOTTPOFF";
 208   case VK_INDNTPOFF: return "INDNTPOFF";
 209   case VK_NTPOFF: return "NTPOFF";
 210   case VK_GOTNTPOFF: return "GOTNTPOFF";
 211   case VK_PLT: return "PLT";
 212   case VK_TLSGD: return "TLSGD";
 213   case VK_TLSLD: return "TLSLD";
 214   case VK_TLSLDM: return "TLSLDM";
 215   case VK_TPOFF: return "TPOFF";
 216   case VK_TPREL: return "TPREL";
 217   case VK_TLSCALL: return "tlscall";
 218   case VK_TLSDESC: return "tlsdesc";
 219   case VK_TLVP: return "TLVP";
 220   case VK_TLVPPAGE: return "TLVPPAGE";
 221   case VK_TLVPPAGEOFF: return "TLVPPAGEOFF";
 222   case VK_PAGE: return "PAGE";
 223   case VK_PAGEOFF: return "PAGEOFF";
 224   case VK_GOTPAGE: return "GOTPAGE";
 225   case VK_GOTPAGEOFF: return "GOTPAGEOFF";
 226   case VK_SECREL: return "SECREL32";
 227   case VK_SIZE: return "SIZE";
 228   case VK_WEAKREF: return "WEAKREF";
 229   case VK_X86_ABS8: return "ABS8";
 230   case VK_ARM_NONE: return "none";
 231   case VK_ARM_GOT_PREL: return "GOT_PREL";
 232   case VK_ARM_TARGET1: return "target1";
 233   case VK_ARM_TARGET2: return "target2";
 234   case VK_ARM_PREL31: return "prel31";
 235   case VK_ARM_SBREL: return "sbrel";
 236   case VK_ARM_TLSLDO: return "tlsldo";
 237   case VK_ARM_TLSDESCSEQ: return "tlsdescseq";
 238   case VK_AVR_NONE: return "none";
 239   case VK_AVR_LO8: return "lo8";
 240   case VK_AVR_HI8: return "hi8";
 241   case VK_AVR_HLO8: return "hlo8";
 242   case VK_AVR_DIFF8: return "diff8";
 243   case VK_AVR_DIFF16: return "diff16";
 244   case VK_AVR_DIFF32: return "diff32";
 245   case VK_PPC_LO: return "l";
 246   case VK_PPC_HI: return "h";
 247   case VK_PPC_HA: return "ha";
 248   case VK_PPC_HIGH: return "high";
 249   case VK_PPC_HIGHA: return "higha";
 250   case VK_PPC_HIGHER: return "higher";
 251   case VK_PPC_HIGHERA: return "highera";
 252   case VK_PPC_HIGHEST: return "highest";
 253   case VK_PPC_HIGHESTA: return "highesta";
 254   case VK_PPC_GOT_LO: return "got@l";
 255   case VK_PPC_GOT_HI: return "got@h";
 256   case VK_PPC_GOT_HA: return "got@ha";
 257   case VK_PPC_TOCBASE: return "tocbase";
 258   case VK_PPC_TOC: return "toc";
 259   case VK_PPC_TOC_LO: return "toc@l";
 260   case VK_PPC_TOC_HI: return "toc@h";
 261   case VK_PPC_TOC_HA: return "toc@ha";
 262   case VK_PPC_DTPMOD: return "dtpmod";
 263   case VK_PPC_TPREL_LO: return "tprel@l";
 264   case VK_PPC_TPREL_HI: return "tprel@h";
 265   case VK_PPC_TPREL_HA: return "tprel@ha";
 266   case VK_PPC_TPREL_HIGH: return "tprel@high";
 267   case VK_PPC_TPREL_HIGHA: return "tprel@higha";
 268   case VK_PPC_TPREL_HIGHER: return "tprel@higher";
 269   case VK_PPC_TPREL_HIGHERA: return "tprel@highera";
 270   case VK_PPC_TPREL_HIGHEST: return "tprel@highest";
 271   case VK_PPC_TPREL_HIGHESTA: return "tprel@highesta";
 272   case VK_PPC_DTPREL_LO: return "dtprel@l";
 273   case VK_PPC_DTPREL_HI: return "dtprel@h";
 274   case VK_PPC_DTPREL_HA: return "dtprel@ha";
 275   case VK_PPC_DTPREL_HIGH: return "dtprel@high";
 276   case VK_PPC_DTPREL_HIGHA: return "dtprel@higha";
 277   case VK_PPC_DTPREL_HIGHER: return "dtprel@higher";
 278   case VK_PPC_DTPREL_HIGHERA: return "dtprel@highera";
 279   case VK_PPC_DTPREL_HIGHEST: return "dtprel@highest";
 280   case VK_PPC_DTPREL_HIGHESTA: return "dtprel@highesta";
 281   case VK_PPC_GOT_TPREL: return "got@tprel";
 282   case VK_PPC_GOT_TPREL_LO: return "got@tprel@l";
 283   case VK_PPC_GOT_TPREL_HI: return "got@tprel@h";
 284   case VK_PPC_GOT_TPREL_HA: return "got@tprel@ha";
 285   case VK_PPC_GOT_DTPREL: return "got@dtprel";
 286   case VK_PPC_GOT_DTPREL_LO: return "got@dtprel@l";
 287   case VK_PPC_GOT_DTPREL_HI: return "got@dtprel@h";
 288   case VK_PPC_GOT_DTPREL_HA: return "got@dtprel@ha";
 289   case VK_PPC_TLS: return "tls";
 290   case VK_PPC_GOT_TLSGD: return "got@tlsgd";
 291   case VK_PPC_GOT_TLSGD_LO: return "got@tlsgd@l";
 292   case VK_PPC_GOT_TLSGD_HI: return "got@tlsgd@h";
 293   case VK_PPC_GOT_TLSGD_HA: return "got@tlsgd@ha";
 294   case VK_PPC_TLSGD: return "tlsgd";
 295   case VK_PPC_GOT_TLSLD: return "got@tlsld";
 296   case VK_PPC_GOT_TLSLD_LO: return "got@tlsld@l";
 297   case VK_PPC_GOT_TLSLD_HI: return "got@tlsld@h";
 298   case VK_PPC_GOT_TLSLD_HA: return "got@tlsld@ha";
 299   case VK_PPC_TLSLD: return "tlsld";
 300   case VK_PPC_LOCAL: return "local";
 301   case VK_COFF_IMGREL32: return "IMGREL";
 302   case VK_Hexagon_PCREL: return "PCREL";
 303   case VK_Hexagon_LO16: return "LO16";
 304   case VK_Hexagon_HI16: return "HI16";
 305   case VK_Hexagon_GPREL: return "GPREL";
 306   case VK_Hexagon_GD_GOT: return "GDGOT";
 307   case VK_Hexagon_LD_GOT: return "LDGOT";
 308   case VK_Hexagon_GD_PLT: return "GDPLT";
 309   case VK_Hexagon_LD_PLT: return "LDPLT";
 310   case VK_Hexagon_IE: return "IE";
 311   case VK_Hexagon_IE_GOT: return "IEGOT";
 312   case VK_WASM_TYPEINDEX: return "TYPEINDEX";
 313   case VK_WASM_MBREL: return "MBREL";
 314   case VK_WASM_TBREL: return "TBREL";
 315   case VK_AMDGPU_GOTPCREL32_LO: return "gotpcrel32@lo";
 316   case VK_AMDGPU_GOTPCREL32_HI: return "gotpcrel32@hi";
 317   case VK_AMDGPU_REL32_LO: return "rel32@lo";
 318   case VK_AMDGPU_REL32_HI: return "rel32@hi";
 319   case VK_AMDGPU_REL64: return "rel64";
 320   case VK_AMDGPU_ABS32_LO: return "abs32@lo";
 321   case VK_AMDGPU_ABS32_HI: return "abs32@hi";
 322   }
 323   llvm_unreachable("Invalid variant kind");
 324 }
 325
 326 MCSymbolRefExpr::VariantKind
 327 MCSymbolRefExpr::getVariantKindForName(StringRef Name) {
 328   return StringSwitch<VariantKind>(Name.lower())
 329     .Case("dtprel", VK_DTPREL)
 330     .Case("dtpoff", VK_DTPOFF)
 331     .Case("got", VK_GOT)
 332     .Case("gotoff", VK_GOTOFF)
 333     .Case("gotrel", VK_GOTREL)
 334     .Case("gotpcrel", VK_GOTPCREL)
 335     .Case("gottpoff", VK_GOTTPOFF)
 336     .Case("indntpoff", VK_INDNTPOFF)
 337     .Case("ntpoff", VK_NTPOFF)
 338     .Case("gotntpoff", VK_GOTNTPOFF)
 339     .Case("plt", VK_PLT)
 340     .Case("tlscall", VK_TLSCALL)
 341     .Case("tlsdesc", VK_TLSDESC)
 342     .Case("tlsgd", VK_TLSGD)
 343     .Case("tlsld", VK_TLSLD)
 344     .Case("tlsldm", VK_TLSLDM)
 345     .Case("tpoff", VK_TPOFF)
 346     .Case("tprel", VK_TPREL)
 347     .Case("tlvp", VK_TLVP)
 348     .Case("tlvppage", VK_TLVPPAGE)
 349     .Case("tlvppageoff", VK_TLVPPAGEOFF)
 350     .Case("page", VK_PAGE)
 351     .Case("pageoff", VK_PAGEOFF)
 352     .Case("gotpage", VK_GOTPAGE)
 353     .Case("gotpageoff", VK_GOTPAGEOFF)
 354     .Case("imgrel", VK_COFF_IMGREL32)
 355     .Case("secrel32", VK_SECREL)
 356     .Case("size", VK_SIZE)
 357     .Case("abs8", VK_X86_ABS8)
 358     .Case("l", VK_PPC_LO)
 359     .Case("h", VK_PPC_HI)
 360     .Case("ha", VK_PPC_HA)
 361     .Case("high", VK_PPC_HIGH)
 362     .Case("higha", VK_PPC_HIGHA)
 363     .Case("higher", VK_PPC_HIGHER)
 364     .Case("highera", VK_PPC_HIGHERA)
 365     .Case("highest", VK_PPC_HIGHEST)
 366     .Case("highesta", VK_PPC_HIGHESTA)
 367     .Case("got@l", VK_PPC_GOT_LO)
 368     .Case("got@h", VK_PPC_GOT_HI)
 369     .Case("got@ha", VK_PPC_GOT_HA)
 370     .Case("local", VK_PPC_LOCAL)
 371     .Case("tocbase", VK_PPC_TOCBASE)
 372     .Case("toc", VK_PPC_TOC)
 373     .Case("toc@l", VK_PPC_TOC_LO)
 374     .Case("toc@h", VK_PPC_TOC_HI)
 375     .Case("toc@ha", VK_PPC_TOC_HA)
 376     .Case("tls", VK_PPC_TLS)
 377     .Case("dtpmod", VK_PPC_DTPMOD)
 378     .Case("tprel@l", VK_PPC_TPREL_LO)
 379     .Case("tprel@h", VK_PPC_TPREL_HI)
 380     .Case("tprel@ha", VK_PPC_TPREL_HA)
 381     .Case("tprel@high", VK_PPC_TPREL_HIGH)
 382     .Case("tprel@higha", VK_PPC_TPREL_HIGHA)
 383     .Case("tprel@higher", VK_PPC_TPREL_HIGHER)
 384     .Case("tprel@highera", VK_PPC_TPREL_HIGHERA)
 385     .Case("tprel@highest", VK_PPC_TPREL_HIGHEST)
 386     .Case("tprel@highesta", VK_PPC_TPREL_HIGHESTA)
 387     .Case("dtprel@l", VK_PPC_DTPREL_LO)
 388     .Case("dtprel@h", VK_PPC_DTPREL_HI)
 389     .Case("dtprel@ha", VK_PPC_DTPREL_HA)
 390     .Case("dtprel@high", VK_PPC_DTPREL_HIGH)
 391     .Case("dtprel@higha", VK_PPC_DTPREL_HIGHA)
 392     .Case("dtprel@higher", VK_PPC_DTPREL_HIGHER)
 393     .Case("dtprel@highera", VK_PPC_DTPREL_HIGHERA)
 394     .Case("dtprel@highest", VK_PPC_DTPREL_HIGHEST)
 395     .Case("dtprel@highesta", VK_PPC_DTPREL_HIGHESTA)
 396     .Case("got@tprel", VK_PPC_GOT_TPREL)
 397     .Case("got@tprel@l", VK_PPC_GOT_TPREL_LO)
 398     .Case("got@tprel@h", VK_PPC_GOT_TPREL_HI)
 399     .Case("got@tprel@ha", VK_PPC_GOT_TPREL_HA)
 400     .Case("got@dtprel", VK_PPC_GOT_DTPREL)
 401     .Case("got@dtprel@l", VK_PPC_GOT_DTPREL_LO)
 402     .Case("got@dtprel@h", VK_PPC_GOT_DTPREL_HI)
 403     .Case("got@dtprel@ha", VK_PPC_GOT_DTPREL_HA)
 404     .Case("got@tlsgd", VK_PPC_GOT_TLSGD)
 405     .Case("got@tlsgd@l", VK_PPC_GOT_TLSGD_LO)
 406     .Case("got@tlsgd@h", VK_PPC_GOT_TLSGD_HI)
 407     .Case("got@tlsgd@ha", VK_PPC_GOT_TLSGD_HA)
 408     .Case("got@tlsld", VK_PPC_GOT_TLSLD)
 409     .Case("got@tlsld@l", VK_PPC_GOT_TLSLD_LO)
 410     .Case("got@tlsld@h", VK_PPC_GOT_TLSLD_HI)
 411     .Case("got@tlsld@ha", VK_PPC_GOT_TLSLD_HA)
 412     .Case("gdgot", VK_Hexagon_GD_GOT)
 413     .Case("gdplt", VK_Hexagon_GD_PLT)
 414     .Case("iegot", VK_Hexagon_IE_GOT)
 415     .Case("ie", VK_Hexagon_IE)
 416     .Case("ldgot", VK_Hexagon_LD_GOT)
 417     .Case("ldplt", VK_Hexagon_LD_PLT)
 418     .Case("pcrel", VK_Hexagon_PCREL)
 419     .Case("none", VK_ARM_NONE)
 420     .Case("got_prel", VK_ARM_GOT_PREL)
 421     .Case("target1", VK_ARM_TARGET1)
 422     .Case("target2", VK_ARM_TARGET2)
 423     .Case("prel31", VK_ARM_PREL31)
 424     .Case("sbrel", VK_ARM_SBREL)
 425     .Case("tlsldo", VK_ARM_TLSLDO)
 426     .Case("lo8", VK_AVR_LO8)
 427     .Case("hi8", VK_AVR_HI8)
 428     .Case("hlo8", VK_AVR_HLO8)
 429     .Case("typeindex", VK_WASM_TYPEINDEX)
 430     .Case("tbrel", VK_WASM_TBREL)
 431     .Case("mbrel", VK_WASM_MBREL)
 432     .Case("gotpcrel32@lo", VK_AMDGPU_GOTPCREL32_LO)
 433     .Case("gotpcrel32@hi", VK_AMDGPU_GOTPCREL32_HI)
 434     .Case("rel32@lo", VK_AMDGPU_REL32_LO)
 435     .Case("rel32@hi", VK_AMDGPU_REL32_HI)
 436     .Case("rel64", VK_AMDGPU_REL64)
 437     .Case("abs32@lo", VK_AMDGPU_ABS32_LO)
 438     .Case("abs32@hi", VK_AMDGPU_ABS32_HI)
 439     .Default(VK_Invalid);
 440 }
 441
 442 void MCSymbolRefExpr::printVariantKind(raw_ostream &OS) const {
 443   if (UseParensForSymbolVariant)
 444     OS << '(' << MCSymbolRefExpr::getVariantKindName(getKind()) << ')';
 445   else
 446     OS << '@' << MCSymbolRefExpr::getVariantKindName(getKind());
 447 }
 448
 449 /* *** */
 450
 451 void MCTargetExpr::anchor() {}
 452
 453 /* *** */
 454
 455 bool MCExpr::evaluateAsAbsolute(int64_t &Res) const {
 456   return evaluateAsAbsolute(Res, nullptr, nullptr, nullptr, false);
 457 }
 458
 459 bool MCExpr::evaluateAsAbsolute(int64_t &Res,
 460                                 const MCAsmLayout &Layout) const {
 461   return evaluateAsAbsolute(Res, &Layout.getAssembler(), &Layout, nullptr, false);
 462 }
 463
 464 bool MCExpr::evaluateAsAbsolute(int64_t &Res,
 465                                 const MCAsmLayout &Layout,
 466                                 const SectionAddrMap &Addrs) const {
 467   // Setting InSet causes us to absolutize differences across sections and that
 468   // is what the MachO writer uses Addrs for.
 469   return evaluateAsAbsolute(Res, &Layout.getAssembler(), &Layout, &Addrs, true);
 470 }
 471
 472 bool MCExpr::evaluateAsAbsolute(int64_t &Res, const MCAssembler &Asm) const {
 473   return evaluateAsAbsolute(Res, &Asm, nullptr, nullptr, false);
 474 }
 475
 476 bool MCExpr::evaluateAsAbsolute(int64_t &Res, const MCAssembler *Asm) const {
 477   return evaluateAsAbsolute(Res, Asm, nullptr, nullptr, false);
 478 }
 479
 480 bool MCExpr::evaluateKnownAbsolute(int64_t &Res,
 481                                    const MCAsmLayout &Layout) const {
 482   return evaluateAsAbsolute(Res, &Layout.getAssembler(), &Layout, nullptr,
 483                             true);
 484 }
 485
 486 bool MCExpr::evaluateAsAbsolute(int64_t &Res, const MCAssembler *Asm,
 487                                 const MCAsmLayout *Layout,
 488                                 const SectionAddrMap *Addrs, bool InSet) const {
 489   MCValue Value;
 490
 491   // Fast path constants.
 492   if (const MCConstantExpr *CE = dyn_cast<MCConstantExpr>(this)) {
 493     Res = CE->getValue();
 494     return true;
 495   }
 496
 497   bool IsRelocatable =
 498       evaluateAsRelocatableImpl(Value, Asm, Layout, nullptr, Addrs, InSet);
 499
 500   // Record the current value.
 501   Res = Value.getConstant();
 502
 503   return IsRelocatable && Value.isAbsolute();
 504 }
 505
 506 /// Helper method for \see EvaluateSymbolAdd().
 507 static void AttemptToFoldSymbolOffsetDifference(
 508     const MCAssembler *Asm, const MCAsmLayout *Layout,
 509     const SectionAddrMap *Addrs, bool InSet, const MCSymbolRefExpr *&A,
 510     const MCSymbolRefExpr *&B, int64_t &Addend) {
 511   if (!A || !B)
 512     return;
 513
 514   const MCSymbol &SA = A->getSymbol();
 515   const MCSymbol &SB = B->getSymbol();
 516
 517   if (SA.isUndefined() || SB.isUndefined())
 518     return;
 519
 520   if (!Asm->getWriter().isSymbolRefDifferenceFullyResolved(*Asm, A, B, InSet))
 521     return;
 522
 523   if (SA.getFragment() == SB.getFragment() && !SA.isVariable() &&
 524       !SA.isUnset() && !SB.isVariable() && !SB.isUnset()) {
 525     Addend += (SA.getOffset() - SB.getOffset());
 526
 527     // Pointers to Thumb symbols need to have their low-bit set to allow
 528     // for interworking.
 529     if (Asm->isThumbFunc(&SA))
 530       Addend |= 1;
 531
 532     // If symbol is labeled as micromips, we set low-bit to ensure
 533     // correct offset in .gcc_except_table
 534     if (Asm->getBackend().isMicroMips(&SA))
 535       Addend |= 1;
 536
 537     // Clear the symbol expr pointers to indicate we have folded these
 538     // operands.
 539     A = B = nullptr;
 540     return;
 541   }
 542
 543   if (!Layout)
 544     return;
 545
 546   const MCSection &SecA = *SA.getFragment()->getParent();
 547   const MCSection &SecB = *SB.getFragment()->getParent();
 548
 549   if ((&SecA != &SecB) && !Addrs)
 550     return;
 551
 552   // Eagerly evaluate.
 553   Addend += Layout->getSymbolOffset(A->getSymbol()) -
 554             Layout->getSymbolOffset(B->getSymbol());
 555   if (Addrs && (&SecA != &SecB))
 556     Addend += (Addrs->lookup(&SecA) - Addrs->lookup(&SecB));
 557
 558   // Pointers to Thumb symbols need to have their low-bit set to allow
 559   // for interworking.
 560   if (Asm->isThumbFunc(&SA))
 561     Addend |= 1;
 562
 563   // If symbol is labeled as micromips, we set low-bit to ensure
 564   // correct offset in .gcc_except_table
 565   if (Asm->getBackend().isMicroMips(&SA))
 566     Addend |= 1;
 567
 568   // Clear the symbol expr pointers to indicate we have folded these
 569   // operands.
 570   A = B = nullptr;
 571 }
 572
 573 static bool canFold(const MCAssembler *Asm, const MCSymbolRefExpr *A,
 574                     const MCSymbolRefExpr *B, bool InSet) {
 575   if (InSet)
 576     return true;
 577
 578   if (!Asm->getBackend().requiresDiffExpressionRelocations())
 579     return true;
 580
 581   const MCSymbol &CheckSym = A ? A->getSymbol() : B->getSymbol();
 582   if (!CheckSym.isInSection())
 583     return true;
 584
 585   if (!CheckSym.getSection().hasInstructions())
 586     return true;
 587
 588   return false;
 589 }
 590
 591 /// Evaluate the result of an add between (conceptually) two MCValues.
 592 ///
 593 /// This routine conceptually attempts to construct an MCValue:
 594 ///   Result = (Result_A - Result_B + Result_Cst)
 595 /// from two MCValue's LHS and RHS where
 596 ///   Result = LHS + RHS
 597 /// and
 598 ///   Result = (LHS_A - LHS_B + LHS_Cst) + (RHS_A - RHS_B + RHS_Cst).
 599 ///
 600 /// This routine attempts to aggresively fold the operands such that the result
 601 /// is representable in an MCValue, but may not always succeed.
 602 ///
 603 /// \returns True on success, false if the result is not representable in an
 604 /// MCValue.
 605
 606 /// NOTE: It is really important to have both the Asm and Layout arguments.
 607 /// They might look redundant, but this function can be used before layout
 608 /// is done (see the object streamer for example) and having the Asm argument
 609 /// lets us avoid relaxations early.
 610 static bool
 611 EvaluateSymbolicAdd(const MCAssembler *Asm, const MCAsmLayout *Layout,
 612                     const SectionAddrMap *Addrs, bool InSet, const MCValue &LHS,
 613                     const MCSymbolRefExpr *RHS_A, const MCSymbolRefExpr *RHS_B,
 614                     int64_t RHS_Cst, MCValue &Res) {
 615   // FIXME: This routine (and other evaluation parts) are *incredibly* sloppy
 616   // about dealing with modifiers. This will ultimately bite us, one day.
 617   const MCSymbolRefExpr *LHS_A = LHS.getSymA();
 618   const MCSymbolRefExpr *LHS_B = LHS.getSymB();
 619   int64_t LHS_Cst = LHS.getConstant();
 620
 621   // Fold the result constant immediately.
 622   int64_t Result_Cst = LHS_Cst + RHS_Cst;
 623
 624   assert((!Layout || Asm) &&
 625          "Must have an assembler object if layout is given!");
 626
 627   // If we have a layout, we can fold resolved differences. Do not do this if
 628   // the backend requires this to be emitted as individual relocations, unless
 629   // the InSet flag is set to get the current difference anyway (used for
 630   // example to calculate symbol sizes).
 631   if (Asm && canFold(Asm, LHS_A, LHS_B, InSet)) {
 632     // First, fold out any differences which are fully resolved. By
 633     // reassociating terms in
 634     //   Result = (LHS_A - LHS_B + LHS_Cst) + (RHS_A - RHS_B + RHS_Cst).
 635     // we have the four possible differences:
 636     //   (LHS_A - LHS_B),
 637     //   (LHS_A - RHS_B),
 638     //   (RHS_A - LHS_B),
 639     //   (RHS_A - RHS_B).
 640     // Since we are attempting to be as aggressive as possible about folding, we
 641     // attempt to evaluate each possible alternative.
 642     AttemptToFoldSymbolOffsetDifference(Asm, Layout, Addrs, InSet, LHS_A, LHS_B,
 643                                         Result_Cst);
 644     AttemptToFoldSymbolOffsetDifference(Asm, Layout, Addrs, InSet, LHS_A, RHS_B,
 645                                         Result_Cst);
 646     AttemptToFoldSymbolOffsetDifference(Asm, Layout, Addrs, InSet, RHS_A, LHS_B,
 647                                         Result_Cst);
 648     AttemptToFoldSymbolOffsetDifference(Asm, Layout, Addrs, InSet, RHS_A, RHS_B,
 649                                         Result_Cst);
 650   }
 651
 652   // We can't represent the addition or subtraction of two symbols.
 653   if ((LHS_A && RHS_A) || (LHS_B && RHS_B))
 654     return false;
 655
 656   // At this point, we have at most one additive symbol and one subtractive
 657   // symbol -- find them.
 658   const MCSymbolRefExpr *A = LHS_A ? LHS_A : RHS_A;
 659   const MCSymbolRefExpr *B = LHS_B ? LHS_B : RHS_B;
 660
 661   Res = MCValue::get(A, B, Result_Cst);
 662   return true;
 663 }
 664
 665 bool MCExpr::evaluateAsRelocatable(MCValue &Res,
 666                                    const MCAsmLayout *Layout,
 667                                    const MCFixup *Fixup) const {
 668   MCAssembler *Assembler = Layout ? &Layout->getAssembler() : nullptr;
 669   return evaluateAsRelocatableImpl(Res, Assembler, Layout, Fixup, nullptr,
 670                                    false);
 671 }
 672
 673 bool MCExpr::evaluateAsValue(MCValue &Res, const MCAsmLayout &Layout) const {
 674   MCAssembler *Assembler = &Layout.getAssembler();
 675   return evaluateAsRelocatableImpl(Res, Assembler, &Layout, nullptr, nullptr,
 676                                    true);
 677 }
 678
 679 static bool canExpand(const MCSymbol &Sym, bool InSet) {
 680   const MCExpr *Expr = Sym.getVariableValue();
 681   const auto *Inner = dyn_cast<MCSymbolRefExpr>(Expr);
 682   if (Inner) {
 683     if (Inner->getKind() == MCSymbolRefExpr::VK_WEAKREF)
 684       return false;
 685   }
 686
 687   if (InSet)
 688     return true;
 689   return !Sym.isInSection();
 690 }
 691
 692 bool MCExpr::evaluateAsRelocatableImpl(MCValue &Res, const MCAssembler *Asm,
 693                                        const MCAsmLayout *Layout,
 694                                        const MCFixup *Fixup,
 695                                        const SectionAddrMap *Addrs,
 696                                        bool InSet) const {
 697   ++stats::MCExprEvaluate;
 698
 699   switch (getKind()) {
 700   case Target:
 701     return cast<MCTargetExpr>(this)->evaluateAsRelocatableImpl(Res, Layout,
 702                                                                Fixup);
 703
 704   case Constant:
 705     Res = MCValue::get(cast<MCConstantExpr>(this)->getValue());
 706     return true;
 707
 708   case SymbolRef: {
 709     const MCSymbolRefExpr *SRE = cast<MCSymbolRefExpr>(this);
 710     const MCSymbol &Sym = SRE->getSymbol();
 711
 712     // Evaluate recursively if this is a variable.
 713     if (Sym.isVariable() && SRE->getKind() == MCSymbolRefExpr::VK_None &&
 714         canExpand(Sym, InSet)) {
 715       bool IsMachO = SRE->hasSubsectionsViaSymbols();
 716       if (Sym.getVariableValue()->evaluateAsRelocatableImpl(
 717               Res, Asm, Layout, Fixup, Addrs, InSet || IsMachO)) {
 718         if (!IsMachO)
 719           return true;
 720
 721         const MCSymbolRefExpr *A = Res.getSymA();
 722         const MCSymbolRefExpr *B = Res.getSymB();
 723         // FIXME: This is small hack. Given
 724         // a = b + 4
 725         // .long a
 726         // the OS X assembler will completely drop the 4. We should probably
 727         // include it in the relocation or produce an error if that is not
 728         // possible.
 729         // Allow constant expressions.
 730         if (!A && !B)
 731           return true;
 732         // Allows aliases with zero offset.
 733         if (Res.getConstant() == 0 && (!A || !B))
 734           return true;
 735       }
 736     }
 737
 738     Res = MCValue::get(SRE, nullptr, 0);
 739     return true;
 740   }
 741
 742   case Unary: {
 743     const MCUnaryExpr *AUE = cast<MCUnaryExpr>(this);
 744     MCValue Value;
 745
 746     if (!AUE->getSubExpr()->evaluateAsRelocatableImpl(Value, Asm, Layout, Fixup,
 747                                                       Addrs, InSet))
 748       return false;
 749
 750     switch (AUE->getOpcode()) {
 751     case MCUnaryExpr::LNot:
 752       if (!Value.isAbsolute())
 753         return false;
 754       Res = MCValue::get(!Value.getConstant());
 755       break;
 756     case MCUnaryExpr::Minus:
 757       /// -(a - b + const) ==> (b - a - const)
 758       if (Value.getSymA() && !Value.getSymB())
 759         return false;
 760
 761       // The cast avoids undefined behavior if the constant is INT64_MIN.
 762       Res = MCValue::get(Value.getSymB(), Value.getSymA(),
 763                          -(uint64_t)Value.getConstant());
 764       break;
 765     case MCUnaryExpr::Not:
 766       if (!Value.isAbsolute())
 767         return false;
 768       Res = MCValue::get(~Value.getConstant());
 769       break;
 770     case MCUnaryExpr::Plus:
 771       Res = Value;
 772       break;
 773     }
 774
 775     return true;
 776   }
 777
 778   case Binary: {
 779     const MCBinaryExpr *ABE = cast<MCBinaryExpr>(this);
 780     MCValue LHSValue, RHSValue;
 781
 782     if (!ABE->getLHS()->evaluateAsRelocatableImpl(LHSValue, Asm, Layout, Fixup,
 783                                                   Addrs, InSet) ||
 784         !ABE->getRHS()->evaluateAsRelocatableImpl(RHSValue, Asm, Layout, Fixup,
 785                                                   Addrs, InSet)) {
 786       // Check if both are Target Expressions, see if we can compare them.
 787       if (const MCTargetExpr *L = dyn_cast<MCTargetExpr>(ABE->getLHS()))
 788         if (const MCTargetExpr *R = cast<MCTargetExpr>(ABE->getRHS())) {
 789           switch (ABE->getOpcode()) {
 790           case MCBinaryExpr::EQ:
 791             Res = MCValue::get((L->isEqualTo(R)) ? -1 : 0);
 792             return true;
 793           case MCBinaryExpr::NE:
 794             Res = MCValue::get((R->isEqualTo(R)) ? 0 : -1);
 795             return true;
 796           default: break;
 797           }
 798         }
 799       return false;
 800     }
 801
 802     // We only support a few operations on non-constant expressions, handle
 803     // those first.
 804     if (!LHSValue.isAbsolute() || !RHSValue.isAbsolute()) {
 805       switch (ABE->getOpcode()) {
 806       default:
 807         return false;
 808       case MCBinaryExpr::Sub:
 809         // Negate RHS and add.
 810         // The cast avoids undefined behavior if the constant is INT64_MIN.
 811         return EvaluateSymbolicAdd(Asm, Layout, Addrs, InSet, LHSValue,
 812                                    RHSValue.getSymB(), RHSValue.getSymA(),
 813                                    -(uint64_t)RHSValue.getConstant(), Res);
 814
 815       case MCBinaryExpr::Add:
 816         return EvaluateSymbolicAdd(Asm, Layout, Addrs, InSet, LHSValue,
 817                                    RHSValue.getSymA(), RHSValue.getSymB(),
 818                                    RHSValue.getConstant(), Res);
 819       }
 820     }
 821
 822     // FIXME: We need target hooks for the evaluation. It may be limited in
 823     // width, and gas defines the result of comparisons differently from
 824     // Apple as.
 825     int64_t LHS = LHSValue.getConstant(), RHS = RHSValue.getConstant();
 826     int64_t Result = 0;
 827     auto Op = ABE->getOpcode();
 828     switch (Op) {
 829     case MCBinaryExpr::AShr: Result = LHS >> RHS; break;
 830     case MCBinaryExpr::Add:  Result = LHS + RHS; break;
 831     case MCBinaryExpr::And:  Result = LHS & RHS; break;
 832     case MCBinaryExpr::Div:
 833     case MCBinaryExpr::Mod:
 834       // Handle division by zero. gas just emits a warning and keeps going,
 835       // we try to be stricter.
 836       // FIXME: Currently the caller of this function has no way to understand
 837       // we're bailing out because of 'division by zero'. Therefore, it will
 838       // emit a 'expected relocatable expression' error. It would be nice to
 839       // change this code to emit a better diagnostic.
 840       if (RHS == 0)
 841         return false;
 842       if (ABE->getOpcode() == MCBinaryExpr::Div)
 843         Result = LHS / RHS;
 844       else
 845         Result = LHS % RHS;
 846       break;
 847     case MCBinaryExpr::EQ:   Result = LHS == RHS; break;
 848     case MCBinaryExpr::GT:   Result = LHS > RHS; break;
 849     case MCBinaryExpr::GTE:  Result = LHS >= RHS; break;
 850     case MCBinaryExpr::LAnd: Result = LHS && RHS; break;
 851     case MCBinaryExpr::LOr:  Result = LHS || RHS; break;
 852     case MCBinaryExpr::LShr: Result = uint64_t(LHS) >> uint64_t(RHS); break;
 853     case MCBinaryExpr::LT:   Result = LHS < RHS; break;
 854     case MCBinaryExpr::LTE:  Result = LHS <= RHS; break;
 855     case MCBinaryExpr::Mul:  Result = LHS * RHS; break;
 856     case MCBinaryExpr::NE:   Result = LHS != RHS; break;
 857     case MCBinaryExpr::Or:   Result = LHS | RHS; break;
 858     case MCBinaryExpr::Shl:  Result = uint64_t(LHS) << uint64_t(RHS); break;
 859     case MCBinaryExpr::Sub:  Result = LHS - RHS; break;
 860     case MCBinaryExpr::Xor:  Result = LHS ^ RHS; break;
 861     }
 862
 863     switch (Op) {
 864     default:
 865       Res = MCValue::get(Result);
 866       break;
 867     case MCBinaryExpr::EQ:
 868     case MCBinaryExpr::GT:
 869     case MCBinaryExpr::GTE:
 870     case MCBinaryExpr::LT:
 871     case MCBinaryExpr::LTE:
 872     case MCBinaryExpr::NE:
 873       // A comparison operator returns a -1 if true and 0 if false.
 874       Res = MCValue::get(Result ? -1 : 0);
 875       break;
 876     }
 877
 878     return true;
 879   }
 880   }
 881
 882   llvm_unreachable("Invalid assembly expression kind!");
 883 }
 884
 885 MCFragment *MCExpr::findAssociatedFragment() const {
 886   switch (getKind()) {
 887   case Target:
 888     // We never look through target specific expressions.
 889     return cast<MCTargetExpr>(this)->findAssociatedFragment();
 890
 891   case Constant:
 892     return MCSymbol::AbsolutePseudoFragment;
 893
 894   case SymbolRef: {
 895     const MCSymbolRefExpr *SRE = cast<MCSymbolRefExpr>(this);
 896     const MCSymbol &Sym = SRE->getSymbol();
 897     return Sym.getFragment();
 898   }
 899
 900   case Unary:
 901     return cast<MCUnaryExpr>(this)->getSubExpr()->findAssociatedFragment();
 902
 903   case Binary: {
 904     const MCBinaryExpr *BE = cast<MCBinaryExpr>(this);
 905     MCFragment *LHS_F = BE->getLHS()->findAssociatedFragment();
 906     MCFragment *RHS_F = BE->getRHS()->findAssociatedFragment();
 907
 908     // If either is absolute, return the other.
 909     if (LHS_F == MCSymbol::AbsolutePseudoFragment)
 910       return RHS_F;
 911     if (RHS_F == MCSymbol::AbsolutePseudoFragment)
 912       return LHS_F;
 913
 914     // Not always correct, but probably the best we can do without more context.
 915     if (BE->getOpcode() == MCBinaryExpr::Sub)
 916       return MCSymbol::AbsolutePseudoFragment;
 917
 918     // Otherwise, return the first non-null fragment.
 919     return LHS_F ? LHS_F : RHS_F;
 920   }
 921   }
 922
 923   llvm_unreachable("Invalid assembly expression kind!");
 924 }