llvm/lib/Target/AArch64/MCTargetDesc/AArch64WinCOFFObjectWriter.cpp

   1 //= AArch64WinCOFFObjectWriter.cpp - AArch64 Windows COFF Object Writer C++ =//
   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 "AArch64MCTargetDesc.h"
  10 #include "MCTargetDesc/AArch64FixupKinds.h"
  11 #include "MCTargetDesc/AArch64MCExpr.h"
  12 #include "llvm/ADT/Twine.h"
  13 #include "llvm/BinaryFormat/COFF.h"
  14 #include "llvm/MC/MCAsmBackend.h"
  15 #include "llvm/MC/MCContext.h"
  16 #include "llvm/MC/MCExpr.h"
  17 #include "llvm/MC/MCFixup.h"
  18 #include "llvm/MC/MCFixupKindInfo.h"
  19 #include "llvm/MC/MCObjectWriter.h"
  20 #include "llvm/MC/MCValue.h"
  21 #include "llvm/MC/MCWinCOFFObjectWriter.h"
  22 #include "llvm/Support/Casting.h"
  23 #include "llvm/Support/ErrorHandling.h"
  24 #include <cassert>
  25
  26 using namespace llvm;
  27
  28 namespace {
  29
  30 class AArch64WinCOFFObjectWriter : public MCWinCOFFObjectTargetWriter {
  31 public:
  32   AArch64WinCOFFObjectWriter(const Triple &TheTriple)
  33       : MCWinCOFFObjectTargetWriter(TheTriple.isWindowsArm64EC()
  34                                         ? COFF::IMAGE_FILE_MACHINE_ARM64EC
  35                                         : COFF::IMAGE_FILE_MACHINE_ARM64) {}
  36
  37   ~AArch64WinCOFFObjectWriter() override = default;
  38
  39   unsigned getRelocType(MCContext &Ctx, const MCValue &Target,
  40                         const MCFixup &Fixup, bool IsCrossSection,
  41                         const MCAsmBackend &MAB) const override;
  42
  43   bool recordRelocation(const MCFixup &) const override;
  44 };
  45
  46 } // end anonymous namespace
  47
  48 unsigned AArch64WinCOFFObjectWriter::getRelocType(
  49     MCContext &Ctx, const MCValue &Target, const MCFixup &Fixup,
  50     bool IsCrossSection, const MCAsmBackend &MAB) const {
  51   unsigned FixupKind = Fixup.getKind();
  52   if (IsCrossSection) {
  53     // IMAGE_REL_ARM64_REL64 does not exist. We treat FK_Data_8 as FK_PCRel_4 so
  54     // that .xword a-b can lower to IMAGE_REL_ARM64_REL32. This allows generic
  55     // instrumentation to not bother with the COFF limitation. A negative value
  56     // needs attention.
  57     if (FixupKind != FK_Data_4 && FixupKind != FK_Data_8) {
  58       Ctx.reportError(Fixup.getLoc(), "Cannot represent this expression");
  59       return COFF::IMAGE_REL_ARM64_ADDR32;
  60     }
  61     FixupKind = FK_PCRel_4;
  62   }
  63
  64   auto Modifier = Target.isAbsolute() ? MCSymbolRefExpr::VK_None
  65                                       : Target.getSymA()->getKind();
  66   const MCExpr *Expr = Fixup.getValue();
  67
  68   if (const AArch64MCExpr *A64E = dyn_cast<AArch64MCExpr>(Expr)) {
  69     AArch64MCExpr::VariantKind RefKind = A64E->getKind();
  70     switch (AArch64MCExpr::getSymbolLoc(RefKind)) {
  71     case AArch64MCExpr::VK_ABS:
  72     case AArch64MCExpr::VK_SECREL:
  73       // Supported
  74       break;
  75     default:
  76       Ctx.reportError(Fixup.getLoc(), "relocation variant " +
  77                                           A64E->getVariantKindName() +
  78                                           " unsupported on COFF targets");
  79       return COFF::IMAGE_REL_ARM64_ABSOLUTE; // Dummy return value
  80     }
  81   }
  82
  83   switch (FixupKind) {
  84   default: {
  85     if (const AArch64MCExpr *A64E = dyn_cast<AArch64MCExpr>(Expr)) {
  86       Ctx.reportError(Fixup.getLoc(), "relocation type " +
  87                                           A64E->getVariantKindName() +
  88                                           " unsupported on COFF targets");
  89     } else {
  90       const MCFixupKindInfo &Info = MAB.getFixupKindInfo(Fixup.getKind());
  91       Ctx.reportError(Fixup.getLoc(), Twine("relocation type ") + Info.Name +
  92                                           " unsupported on COFF targets");
  93     }
  94     return COFF::IMAGE_REL_ARM64_ABSOLUTE; // Dummy return value
  95   }
  96
  97   case FK_PCRel_4:
  98     return COFF::IMAGE_REL_ARM64_REL32;
  99
 100   case FK_Data_4:
 101     switch (Modifier) {
 102     default:
 103       return COFF::IMAGE_REL_ARM64_ADDR32;
 104     case MCSymbolRefExpr::VK_COFF_IMGREL32:
 105       return COFF::IMAGE_REL_ARM64_ADDR32NB;
 106     case MCSymbolRefExpr::VK_SECREL:
 107       return COFF::IMAGE_REL_ARM64_SECREL;
 108     }
 109
 110   case FK_Data_8:
 111     return COFF::IMAGE_REL_ARM64_ADDR64;
 112
 113   case FK_SecRel_2:
 114     return COFF::IMAGE_REL_ARM64_SECTION;
 115
 116   case FK_SecRel_4:
 117     return COFF::IMAGE_REL_ARM64_SECREL;
 118
 119   case AArch64::fixup_aarch64_add_imm12:
 120     if (const AArch64MCExpr *A64E = dyn_cast<AArch64MCExpr>(Expr)) {
 121       AArch64MCExpr::VariantKind RefKind = A64E->getKind();
 122       if (RefKind == AArch64MCExpr::VK_SECREL_LO12)
 123         return COFF::IMAGE_REL_ARM64_SECREL_LOW12A;
 124       if (RefKind == AArch64MCExpr::VK_SECREL_HI12)
 125         return COFF::IMAGE_REL_ARM64_SECREL_HIGH12A;
 126     }
 127     return COFF::IMAGE_REL_ARM64_PAGEOFFSET_12A;
 128
 129   case AArch64::fixup_aarch64_ldst_imm12_scale1:
 130   case AArch64::fixup_aarch64_ldst_imm12_scale2:
 131   case AArch64::fixup_aarch64_ldst_imm12_scale4:
 132   case AArch64::fixup_aarch64_ldst_imm12_scale8:
 133   case AArch64::fixup_aarch64_ldst_imm12_scale16:
 134     if (const AArch64MCExpr *A64E = dyn_cast<AArch64MCExpr>(Expr)) {
 135       AArch64MCExpr::VariantKind RefKind = A64E->getKind();
 136       if (RefKind == AArch64MCExpr::VK_SECREL_LO12)
 137         return COFF::IMAGE_REL_ARM64_SECREL_LOW12L;
 138     }
 139     return COFF::IMAGE_REL_ARM64_PAGEOFFSET_12L;
 140
 141   case AArch64::fixup_aarch64_pcrel_adr_imm21:
 142     return COFF::IMAGE_REL_ARM64_REL21;
 143
 144   case AArch64::fixup_aarch64_pcrel_adrp_imm21:
 145     return COFF::IMAGE_REL_ARM64_PAGEBASE_REL21;
 146
 147   case AArch64::fixup_aarch64_pcrel_branch14:
 148     return COFF::IMAGE_REL_ARM64_BRANCH14;
 149
 150   case AArch64::fixup_aarch64_pcrel_branch19:
 151     return COFF::IMAGE_REL_ARM64_BRANCH19;
 152
 153   case AArch64::fixup_aarch64_pcrel_branch26:
 154   case AArch64::fixup_aarch64_pcrel_call26:
 155     return COFF::IMAGE_REL_ARM64_BRANCH26;
 156   }
 157 }
 158
 159 bool AArch64WinCOFFObjectWriter::recordRelocation(const MCFixup &Fixup) const {
 160   return true;
 161 }
 162
 163 std::unique_ptr<MCObjectTargetWriter>
 164 llvm::createAArch64WinCOFFObjectWriter(const Triple &TheTriple) {
 165   return std::make_unique<AArch64WinCOFFObjectWriter>(TheTriple);
 166 }