1 //===- lib/MC/MCXCOFFStreamer.cpp - XCOFF Object Output -------------------===// 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 assembles .s files and emits XCOFF .o object files. 10 // 11 //===----------------------------------------------------------------------===// 12 13 #include "llvm/MC/MCXCOFFStreamer.h" 14 #include "llvm/BinaryFormat/XCOFF.h" 15 #include "llvm/MC/MCAsmBackend.h" 16 #include "llvm/MC/MCAssembler.h" 17 #include "llvm/MC/MCCodeEmitter.h" 18 #include "llvm/MC/MCDirectives.h" 19 #include "llvm/MC/MCObjectWriter.h" 20 #include "llvm/MC/MCSectionXCOFF.h" 21 #include "llvm/MC/MCSymbolXCOFF.h" 22 #include "llvm/MC/MCXCOFFObjectWriter.h" 23 #include "llvm/MC/TargetRegistry.h" 24 #include "llvm/Support/Casting.h" 25 26 using namespace llvm; 27 28 MCXCOFFStreamer::MCXCOFFStreamer(MCContext &Context, 29 std::unique_ptr<MCAsmBackend> MAB, 30 std::unique_ptr<MCObjectWriter> OW, 31 std::unique_ptr<MCCodeEmitter> Emitter) 32 : MCObjectStreamer(Context, std::move(MAB), std::move(OW), 33 std::move(Emitter)) {} 34 35 XCOFFObjectWriter &MCXCOFFStreamer::getWriter() { 36 return static_cast<XCOFFObjectWriter &>(getAssembler().getWriter()); 37 } 38 39 bool MCXCOFFStreamer::emitSymbolAttribute(MCSymbol *Sym, 40 MCSymbolAttr Attribute) { 41 auto *Symbol = cast<MCSymbolXCOFF>(Sym); 42 getAssembler().registerSymbol(*Symbol); 43 44 switch (Attribute) { 45 // XCOFF doesn't support the cold feature. 46 case MCSA_Cold: 47 return false; 48 49 case MCSA_Global: 50 case MCSA_Extern: 51 Symbol->setStorageClass(XCOFF::C_EXT); 52 Symbol->setExternal(true); 53 break; 54 case MCSA_LGlobal: 55 Symbol->setStorageClass(XCOFF::C_HIDEXT); 56 Symbol->setExternal(true); 57 break; 58 case llvm::MCSA_Weak: 59 Symbol->setStorageClass(XCOFF::C_WEAKEXT); 60 Symbol->setExternal(true); 61 break; 62 case llvm::MCSA_Hidden: 63 Symbol->setVisibilityType(XCOFF::SYM_V_HIDDEN); 64 break; 65 case llvm::MCSA_Protected: 66 Symbol->setVisibilityType(XCOFF::SYM_V_PROTECTED); 67 break; 68 case llvm::MCSA_Exported: 69 Symbol->setVisibilityType(XCOFF::SYM_V_EXPORTED); 70 break; 71 default: 72 report_fatal_error("Not implemented yet."); 73 } 74 return true; 75 } 76 77 void MCXCOFFStreamer::emitXCOFFSymbolLinkageWithVisibility( 78 MCSymbol *Symbol, MCSymbolAttr Linkage, MCSymbolAttr Visibility) { 79 80 emitSymbolAttribute(Symbol, Linkage); 81 82 // When the caller passes `MCSA_Invalid` for the visibility, do not emit one. 83 if (Visibility == MCSA_Invalid) 84 return; 85 86 emitSymbolAttribute(Symbol, Visibility); 87 } 88 89 void MCXCOFFStreamer::emitXCOFFRefDirective(const MCSymbol *Symbol) { 90 // Add a Fixup here to later record a relocation of type R_REF to prevent the 91 // ref symbol from being garbage collected (by the binder). 92 MCDataFragment *DF = getOrCreateDataFragment(); 93 const MCSymbolRefExpr *SRE = MCSymbolRefExpr::create(Symbol, getContext()); 94 std::optional<MCFixupKind> MaybeKind = 95 getAssembler().getBackend().getFixupKind("R_REF"); 96 if (!MaybeKind) 97 report_fatal_error("failed to get fixup kind for R_REF relocation"); 98 99 MCFixupKind Kind = *MaybeKind; 100 MCFixup Fixup = MCFixup::create(DF->getContents().size(), SRE, Kind); 101 DF->getFixups().push_back(Fixup); 102 } 103 104 void MCXCOFFStreamer::emitXCOFFRenameDirective(const MCSymbol *Name, 105 StringRef Rename) { 106 const MCSymbolXCOFF *Symbol = cast<const MCSymbolXCOFF>(Name); 107 if (!Symbol->hasRename()) 108 report_fatal_error("Only explicit .rename is supported for XCOFF."); 109 } 110 111 void MCXCOFFStreamer::emitXCOFFExceptDirective(const MCSymbol *Symbol, 112 const MCSymbol *Trap, 113 unsigned Lang, unsigned Reason, 114 unsigned FunctionSize, 115 bool hasDebug) { 116 getWriter().addExceptionEntry(Symbol, Trap, Lang, Reason, FunctionSize, 117 hasDebug); 118 } 119 120 void MCXCOFFStreamer::emitXCOFFCInfoSym(StringRef Name, StringRef Metadata) { 121 getWriter().addCInfoSymEntry(Name, Metadata); 122 } 123 124 void MCXCOFFStreamer::emitCommonSymbol(MCSymbol *Symbol, uint64_t Size, 125 Align ByteAlignment) { 126 getAssembler().registerSymbol(*Symbol); 127 Symbol->setExternal(cast<MCSymbolXCOFF>(Symbol)->getStorageClass() != 128 XCOFF::C_HIDEXT); 129 Symbol->setCommon(Size, ByteAlignment); 130 131 // Default csect align is 4, but common symbols have explicit alignment values 132 // and we should honor it. 133 cast<MCSymbolXCOFF>(Symbol)->getRepresentedCsect()->setAlignment( 134 ByteAlignment); 135 136 // Emit the alignment and storage for the variable to the section. 137 emitValueToAlignment(ByteAlignment); 138 emitZeros(Size); 139 } 140 141 void MCXCOFFStreamer::emitZerofill(MCSection *Section, MCSymbol *Symbol, 142 uint64_t Size, Align ByteAlignment, 143 SMLoc Loc) { 144 report_fatal_error("Zero fill not implemented for XCOFF."); 145 } 146 147 void MCXCOFFStreamer::emitInstToData(const MCInst &Inst, 148 const MCSubtargetInfo &STI) { 149 MCAssembler &Assembler = getAssembler(); 150 SmallVector<MCFixup, 4> Fixups; 151 SmallString<256> Code; 152 Assembler.getEmitter().encodeInstruction(Inst, Code, Fixups, STI); 153 154 // Add the fixups and data. 155 MCDataFragment *DF = getOrCreateDataFragment(&STI); 156 const size_t ContentsSize = DF->getContents().size(); 157 auto &DataFragmentFixups = DF->getFixups(); 158 for (auto &Fixup : Fixups) { 159 Fixup.setOffset(Fixup.getOffset() + ContentsSize); 160 DataFragmentFixups.push_back(Fixup); 161 } 162 163 DF->setHasInstructions(STI); 164 DF->appendContents(Code); 165 } 166 167 void MCXCOFFStreamer::emitXCOFFLocalCommonSymbol(MCSymbol *LabelSym, 168 uint64_t Size, 169 MCSymbol *CsectSym, 170 Align Alignment) { 171 emitCommonSymbol(CsectSym, Size, Alignment); 172 } 173