| //===- lib/MC/AArch64ELFStreamer.cpp - ELF Object Output for AArch64 ------===// |
| // |
| // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| // See https://llvm.org/LICENSE.txt for license information. |
| // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // This file assembles .s files and emits AArch64 ELF .o object files. Different |
| // from generic ELF streamer in emitting mapping symbols ($x and $d) to delimit |
| // regions of data and code. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "AArch64ELFStreamer.h" |
| #include "AArch64MCTargetDesc.h" |
| #include "AArch64TargetStreamer.h" |
| #include "AArch64WinCOFFStreamer.h" |
| #include "llvm/ADT/DenseMap.h" |
| #include "llvm/ADT/StringRef.h" |
| #include "llvm/ADT/Triple.h" |
| #include "llvm/ADT/Twine.h" |
| #include "llvm/BinaryFormat/ELF.h" |
| #include "llvm/MC/MCAsmBackend.h" |
| #include "llvm/MC/MCAssembler.h" |
| #include "llvm/MC/MCCodeEmitter.h" |
| #include "llvm/MC/MCContext.h" |
| #include "llvm/MC/MCELFStreamer.h" |
| #include "llvm/MC/MCExpr.h" |
| #include "llvm/MC/MCInst.h" |
| #include "llvm/MC/MCObjectWriter.h" |
| #include "llvm/MC/MCSection.h" |
| #include "llvm/MC/MCStreamer.h" |
| #include "llvm/MC/MCSubtargetInfo.h" |
| #include "llvm/MC/MCSymbolELF.h" |
| #include "llvm/MC/MCWinCOFFStreamer.h" |
| #include "llvm/Support/Casting.h" |
| #include "llvm/Support/FormattedStream.h" |
| #include "llvm/Support/raw_ostream.h" |
| |
| using namespace llvm; |
| |
| namespace { |
| |
| class AArch64ELFStreamer; |
| |
| class AArch64TargetAsmStreamer : public AArch64TargetStreamer { |
| formatted_raw_ostream &OS; |
| |
| void emitInst(uint32_t Inst) override; |
| |
| void emitDirectiveVariantPCS(MCSymbol *Symbol) override { |
| OS << "\t.variant_pcs\t" << Symbol->getName() << "\n"; |
| } |
| |
| void emitARM64WinCFIAllocStack(unsigned Size) override { |
| OS << "\t.seh_stackalloc\t" << Size << "\n"; |
| } |
| void emitARM64WinCFISaveR19R20X(int Offset) override { |
| OS << "\t.seh_save_r19r20_x\t" << Offset << "\n"; |
| } |
| void emitARM64WinCFISaveFPLR(int Offset) override { |
| OS << "\t.seh_save_fplr\t" << Offset << "\n"; |
| } |
| void emitARM64WinCFISaveFPLRX(int Offset) override { |
| OS << "\t.seh_save_fplr_x\t" << Offset << "\n"; |
| } |
| void emitARM64WinCFISaveReg(unsigned Reg, int Offset) override { |
| OS << "\t.seh_save_reg\tx" << Reg << ", " << Offset << "\n"; |
| } |
| void emitARM64WinCFISaveRegX(unsigned Reg, int Offset) override { |
| OS << "\t.seh_save_reg_x\tx" << Reg << ", " << Offset << "\n"; |
| } |
| void emitARM64WinCFISaveRegP(unsigned Reg, int Offset) override { |
| OS << "\t.seh_save_regp\tx" << Reg << ", " << Offset << "\n"; |
| } |
| void emitARM64WinCFISaveRegPX(unsigned Reg, int Offset) override { |
| OS << "\t.seh_save_regp_x\tx" << Reg << ", " << Offset << "\n"; |
| } |
| void emitARM64WinCFISaveLRPair(unsigned Reg, int Offset) override { |
| OS << "\t.seh_save_lrpair\tx" << Reg << ", " << Offset << "\n"; |
| } |
| void emitARM64WinCFISaveFReg(unsigned Reg, int Offset) override { |
| OS << "\t.seh_save_freg\td" << Reg << ", " << Offset << "\n"; |
| } |
| void emitARM64WinCFISaveFRegX(unsigned Reg, int Offset) override { |
| OS << "\t.seh_save_freg_x\td" << Reg << ", " << Offset << "\n"; |
| } |
| void emitARM64WinCFISaveFRegP(unsigned Reg, int Offset) override { |
| OS << "\t.seh_save_fregp\td" << Reg << ", " << Offset << "\n"; |
| } |
| void emitARM64WinCFISaveFRegPX(unsigned Reg, int Offset) override { |
| OS << "\t.seh_save_fregp_x\td" << Reg << ", " << Offset << "\n"; |
| } |
| void emitARM64WinCFISetFP() override { OS << "\t.seh_set_fp\n"; } |
| void emitARM64WinCFIAddFP(unsigned Size) override { |
| OS << "\t.seh_add_fp\t" << Size << "\n"; |
| } |
| void emitARM64WinCFINop() override { OS << "\t.seh_nop\n"; } |
| void emitARM64WinCFISaveNext() override { OS << "\t.seh_save_next\n"; } |
| void emitARM64WinCFIPrologEnd() override { OS << "\t.seh_endprologue\n"; } |
| void emitARM64WinCFIEpilogStart() override { OS << "\t.seh_startepilogue\n"; } |
| void emitARM64WinCFIEpilogEnd() override { OS << "\t.seh_endepilogue\n"; } |
| void emitARM64WinCFITrapFrame() override { OS << "\t.seh_trap_frame\n"; } |
| void emitARM64WinCFIMachineFrame() override { OS << "\t.seh_pushframe\n"; } |
| void emitARM64WinCFIContext() override { OS << "\t.seh_context\n"; } |
| void emitARM64WinCFIClearUnwoundToCall() override { |
| OS << "\t.seh_clear_unwound_to_call\n"; |
| } |
| void emitARM64WinCFIPACSignLR() override { |
| OS << "\t.seh_pac_sign_lr\n"; |
| } |
| |
| void emitARM64WinCFISaveAnyRegI(unsigned Reg, int Offset) override { |
| OS << "\t.seh_save_any_reg\tx" << Reg << ", " << Offset << "\n"; |
| } |
| void emitARM64WinCFISaveAnyRegIP(unsigned Reg, int Offset) override { |
| OS << "\t.seh_save_any_reg_p\tx" << Reg << ", " << Offset << "\n"; |
| } |
| void emitARM64WinCFISaveAnyRegD(unsigned Reg, int Offset) override { |
| OS << "\t.seh_save_any_reg\td" << Reg << ", " << Offset << "\n"; |
| } |
| void emitARM64WinCFISaveAnyRegDP(unsigned Reg, int Offset) override { |
| OS << "\t.seh_save_any_reg_p\td" << Reg << ", " << Offset << "\n"; |
| } |
| void emitARM64WinCFISaveAnyRegQ(unsigned Reg, int Offset) override { |
| OS << "\t.seh_save_any_reg\tq" << Reg << ", " << Offset << "\n"; |
| } |
| void emitARM64WinCFISaveAnyRegQP(unsigned Reg, int Offset) override { |
| OS << "\t.seh_save_any_reg_p\tq" << Reg << ", " << Offset << "\n"; |
| } |
| void emitARM64WinCFISaveAnyRegIX(unsigned Reg, int Offset) override { |
| OS << "\t.seh_save_any_reg_x\tx" << Reg << ", " << Offset << "\n"; |
| } |
| void emitARM64WinCFISaveAnyRegIPX(unsigned Reg, int Offset) override { |
| OS << "\t.seh_save_any_reg_px\tx" << Reg << ", " << Offset << "\n"; |
| } |
| void emitARM64WinCFISaveAnyRegDX(unsigned Reg, int Offset) override { |
| OS << "\t.seh_save_any_reg_x\td" << Reg << ", " << Offset << "\n"; |
| } |
| void emitARM64WinCFISaveAnyRegDPX(unsigned Reg, int Offset) override { |
| OS << "\t.seh_save_any_reg_px\td" << Reg << ", " << Offset << "\n"; |
| } |
| void emitARM64WinCFISaveAnyRegQX(unsigned Reg, int Offset) override { |
| OS << "\t.seh_save_any_reg_x\tq" << Reg << ", " << Offset << "\n"; |
| } |
| void emitARM64WinCFISaveAnyRegQPX(unsigned Reg, int Offset) override { |
| OS << "\t.seh_save_any_reg_px\tq" << Reg << ", " << Offset << "\n"; |
| } |
| |
| public: |
| AArch64TargetAsmStreamer(MCStreamer &S, formatted_raw_ostream &OS); |
| }; |
| |
| AArch64TargetAsmStreamer::AArch64TargetAsmStreamer(MCStreamer &S, |
| formatted_raw_ostream &OS) |
| : AArch64TargetStreamer(S), OS(OS) {} |
| |
| void AArch64TargetAsmStreamer::emitInst(uint32_t Inst) { |
| OS << "\t.inst\t0x" << Twine::utohexstr(Inst) << "\n"; |
| } |
| |
| /// Extend the generic ELFStreamer class so that it can emit mapping symbols at |
| /// the appropriate points in the object files. These symbols are defined in the |
| /// AArch64 ELF ABI: |
| /// infocenter.arm.com/help/topic/com.arm.doc.ihi0056a/IHI0056A_aaelf64.pdf |
| /// |
| /// In brief: $x or $d should be emitted at the start of each contiguous region |
| /// of A64 code or data in a section. In practice, this emission does not rely |
| /// on explicit assembler directives but on inherent properties of the |
| /// directives doing the emission (e.g. ".byte" is data, "add x0, x0, x0" an |
| /// instruction). |
| /// |
| /// As a result this system is orthogonal to the DataRegion infrastructure used |
| /// by MachO. Beware! |
| class AArch64ELFStreamer : public MCELFStreamer { |
| public: |
| AArch64ELFStreamer(MCContext &Context, std::unique_ptr<MCAsmBackend> TAB, |
| std::unique_ptr<MCObjectWriter> OW, |
| std::unique_ptr<MCCodeEmitter> Emitter) |
| : MCELFStreamer(Context, std::move(TAB), std::move(OW), |
| std::move(Emitter)), |
| MappingSymbolCounter(0), LastEMS(EMS_None) {} |
| |
| void changeSection(MCSection *Section, const MCExpr *Subsection) override { |
| // We have to keep track of the mapping symbol state of any sections we |
| // use. Each one should start off as EMS_None, which is provided as the |
| // default constructor by DenseMap::lookup. |
| LastMappingSymbols[getPreviousSection().first] = LastEMS; |
| LastEMS = LastMappingSymbols.lookup(Section); |
| |
| MCELFStreamer::changeSection(Section, Subsection); |
| } |
| |
| // Reset state between object emissions |
| void reset() override { |
| MappingSymbolCounter = 0; |
| MCELFStreamer::reset(); |
| LastMappingSymbols.clear(); |
| LastEMS = EMS_None; |
| } |
| |
| /// This function is the one used to emit instruction data into the ELF |
| /// streamer. We override it to add the appropriate mapping symbol if |
| /// necessary. |
| void emitInstruction(const MCInst &Inst, |
| const MCSubtargetInfo &STI) override { |
| emitA64MappingSymbol(); |
| MCELFStreamer::emitInstruction(Inst, STI); |
| } |
| |
| /// Emit a 32-bit value as an instruction. This is only used for the .inst |
| /// directive, EmitInstruction should be used in other cases. |
| void emitInst(uint32_t Inst) { |
| char Buffer[4]; |
| |
| // We can't just use EmitIntValue here, as that will emit a data mapping |
| // symbol, and swap the endianness on big-endian systems (instructions are |
| // always little-endian). |
| for (char &C : Buffer) { |
| C = uint8_t(Inst); |
| Inst >>= 8; |
| } |
| |
| emitA64MappingSymbol(); |
| MCELFStreamer::emitBytes(StringRef(Buffer, 4)); |
| } |
| |
| /// This is one of the functions used to emit data into an ELF section, so the |
| /// AArch64 streamer overrides it to add the appropriate mapping symbol ($d) |
| /// if necessary. |
| void emitBytes(StringRef Data) override { |
| emitDataMappingSymbol(); |
| MCELFStreamer::emitBytes(Data); |
| } |
| |
| /// This is one of the functions used to emit data into an ELF section, so the |
| /// AArch64 streamer overrides it to add the appropriate mapping symbol ($d) |
| /// if necessary. |
| void emitValueImpl(const MCExpr *Value, unsigned Size, SMLoc Loc) override { |
| emitDataMappingSymbol(); |
| MCELFStreamer::emitValueImpl(Value, Size, Loc); |
| } |
| |
| void emitFill(const MCExpr &NumBytes, uint64_t FillValue, |
| SMLoc Loc) override { |
| emitDataMappingSymbol(); |
| MCObjectStreamer::emitFill(NumBytes, FillValue, Loc); |
| } |
| private: |
| enum ElfMappingSymbol { |
| EMS_None, |
| EMS_A64, |
| EMS_Data |
| }; |
| |
| void emitDataMappingSymbol() { |
| if (LastEMS == EMS_Data) |
| return; |
| emitMappingSymbol("$d"); |
| LastEMS = EMS_Data; |
| } |
| |
| void emitA64MappingSymbol() { |
| if (LastEMS == EMS_A64) |
| return; |
| emitMappingSymbol("$x"); |
| LastEMS = EMS_A64; |
| } |
| |
| void emitMappingSymbol(StringRef Name) { |
| auto *Symbol = cast<MCSymbolELF>(getContext().getOrCreateSymbol( |
| Name + "." + Twine(MappingSymbolCounter++))); |
| emitLabel(Symbol); |
| Symbol->setType(ELF::STT_NOTYPE); |
| Symbol->setBinding(ELF::STB_LOCAL); |
| Symbol->setExternal(false); |
| } |
| |
| int64_t MappingSymbolCounter; |
| |
| DenseMap<const MCSection *, ElfMappingSymbol> LastMappingSymbols; |
| ElfMappingSymbol LastEMS; |
| }; |
| |
| } // end anonymous namespace |
| |
| AArch64ELFStreamer &AArch64TargetELFStreamer::getStreamer() { |
| return static_cast<AArch64ELFStreamer &>(Streamer); |
| } |
| |
| void AArch64TargetELFStreamer::emitInst(uint32_t Inst) { |
| getStreamer().emitInst(Inst); |
| } |
| |
| void AArch64TargetELFStreamer::emitDirectiveVariantPCS(MCSymbol *Symbol) { |
| getStreamer().getAssembler().registerSymbol(*Symbol); |
| cast<MCSymbolELF>(Symbol)->setOther(ELF::STO_AARCH64_VARIANT_PCS); |
| } |
| |
| MCTargetStreamer * |
| llvm::createAArch64AsmTargetStreamer(MCStreamer &S, formatted_raw_ostream &OS, |
| MCInstPrinter *InstPrint, |
| bool isVerboseAsm) { |
| return new AArch64TargetAsmStreamer(S, OS); |
| } |
| |
| MCELFStreamer *llvm::createAArch64ELFStreamer( |
| MCContext &Context, std::unique_ptr<MCAsmBackend> TAB, |
| std::unique_ptr<MCObjectWriter> OW, std::unique_ptr<MCCodeEmitter> Emitter, |
| bool RelaxAll) { |
| AArch64ELFStreamer *S = new AArch64ELFStreamer( |
| Context, std::move(TAB), std::move(OW), std::move(Emitter)); |
| if (RelaxAll) |
| S->getAssembler().setRelaxAll(true); |
| return S; |
| } |