llvm/lib/MC/MCAsmBackend.cpp

   1 //===- MCAsmBackend.cpp - Target MC Assembly Backend ----------------------===//
   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/MCAsmBackend.h"
  10 #include "llvm/ADT/None.h"
  11 #include "llvm/ADT/STLExtras.h"
  12 #include "llvm/MC/MCELFObjectWriter.h"
  13 #include "llvm/MC/MCFixupKindInfo.h"
  14 #include "llvm/MC/MCMachObjectWriter.h"
  15 #include "llvm/MC/MCObjectWriter.h"
  16 #include "llvm/MC/MCWasmObjectWriter.h"
  17 #include "llvm/MC/MCWinCOFFObjectWriter.h"
  18 #include "llvm/MC/MCXCOFFObjectWriter.h"
  19 #include <cassert>
  20 #include <cstddef>
  21 #include <cstdint>
  22
  23 using namespace llvm;
  24
  25 MCAsmBackend::MCAsmBackend(support::endianness Endian) : Endian(Endian) {}
  26
  27 MCAsmBackend::~MCAsmBackend() = default;
  28
  29 std::unique_ptr<MCObjectWriter>
  30 MCAsmBackend::createObjectWriter(raw_pwrite_stream &OS) const {
  31   auto TW = createObjectTargetWriter();
  32   switch (TW->getFormat()) {
  33   case Triple::ELF:
  34     return createELFObjectWriter(cast<MCELFObjectTargetWriter>(std::move(TW)), OS,
  35                                  Endian == support::little);
  36   case Triple::MachO:
  37     return createMachObjectWriter(cast<MCMachObjectTargetWriter>(std::move(TW)),
  38                                   OS, Endian == support::little);
  39   case Triple::COFF:
  40     return createWinCOFFObjectWriter(
  41         cast<MCWinCOFFObjectTargetWriter>(std::move(TW)), OS);
  42   case Triple::Wasm:
  43     return createWasmObjectWriter(cast<MCWasmObjectTargetWriter>(std::move(TW)),
  44                                   OS);
  45   case Triple::XCOFF:
  46     return createXCOFFObjectWriter(
  47         cast<MCXCOFFObjectTargetWriter>(std::move(TW)), OS);
  48   default:
  49     llvm_unreachable("unexpected object format");
  50   }
  51 }
  52
  53 std::unique_ptr<MCObjectWriter>
  54 MCAsmBackend::createDwoObjectWriter(raw_pwrite_stream &OS,
  55                                     raw_pwrite_stream &DwoOS) const {
  56   auto TW = createObjectTargetWriter();
  57   switch (TW->getFormat()) {
  58   case Triple::ELF:
  59     return createELFDwoObjectWriter(
  60         cast<MCELFObjectTargetWriter>(std::move(TW)), OS, DwoOS,
  61         Endian == support::little);
  62   case Triple::Wasm:
  63     return createWasmDwoObjectWriter(
  64         cast<MCWasmObjectTargetWriter>(std::move(TW)), OS, DwoOS);
  65   default:
  66     report_fatal_error("dwo only supported with ELF and Wasm");
  67   }
  68 }
  69
  70 Optional<MCFixupKind> MCAsmBackend::getFixupKind(StringRef Name) const {
  71   return None;
  72 }
  73
  74 const MCFixupKindInfo &MCAsmBackend::getFixupKindInfo(MCFixupKind Kind) const {
  75   static const MCFixupKindInfo Builtins[] = {
  76       {"FK_NONE", 0, 0, 0},
  77       {"FK_Data_1", 0, 8, 0},
  78       {"FK_Data_2", 0, 16, 0},
  79       {"FK_Data_4", 0, 32, 0},
  80       {"FK_Data_8", 0, 64, 0},
  81       {"FK_Data_6b", 0, 6, 0},
  82       {"FK_PCRel_1", 0, 8, MCFixupKindInfo::FKF_IsPCRel},
  83       {"FK_PCRel_2", 0, 16, MCFixupKindInfo::FKF_IsPCRel},
  84       {"FK_PCRel_4", 0, 32, MCFixupKindInfo::FKF_IsPCRel},
  85       {"FK_PCRel_8", 0, 64, MCFixupKindInfo::FKF_IsPCRel},
  86       {"FK_GPRel_1", 0, 8, 0},
  87       {"FK_GPRel_2", 0, 16, 0},
  88       {"FK_GPRel_4", 0, 32, 0},
  89       {"FK_GPRel_8", 0, 64, 0},
  90       {"FK_DTPRel_4", 0, 32, 0},
  91       {"FK_DTPRel_8", 0, 64, 0},
  92       {"FK_TPRel_4", 0, 32, 0},
  93       {"FK_TPRel_8", 0, 64, 0},
  94       {"FK_SecRel_1", 0, 8, 0},
  95       {"FK_SecRel_2", 0, 16, 0},
  96       {"FK_SecRel_4", 0, 32, 0},
  97       {"FK_SecRel_8", 0, 64, 0},
  98   };
  99
 100   assert((size_t)Kind <= array_lengthof(Builtins) && "Unknown fixup kind");
 101   return Builtins[Kind];
 102 }
 103
 104 bool MCAsmBackend::fixupNeedsRelaxationAdvanced(
 105     const MCFixup &Fixup, bool Resolved, uint64_t Value,
 106     const MCRelaxableFragment *DF, const MCAsmLayout &Layout,
 107     const bool WasForced) const {
 108   if (!Resolved)
 109     return true;
 110   return fixupNeedsRelaxation(Fixup, Value, DF, Layout);
 111 }