2010-09-30 02:17:26 +00:00
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//===-- ARMAsmBackend.cpp - ARM Assembler Backend -------------------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/Target/TargetAsmBackend.h"
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#include "ARM.h"
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2010-11-09 01:37:15 +00:00
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#include "ARMFixupKinds.h"
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2010-09-30 02:17:26 +00:00
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#include "llvm/ADT/Twine.h"
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#include "llvm/MC/MCAssembler.h"
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#include "llvm/MC/MCExpr.h"
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2010-10-16 18:23:53 +00:00
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#include "llvm/MC/MCObjectFormat.h"
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2010-09-30 02:17:26 +00:00
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#include "llvm/MC/MCObjectWriter.h"
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#include "llvm/MC/MCSectionELF.h"
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#include "llvm/MC/MCSectionMachO.h"
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2010-10-22 15:52:49 +00:00
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#include "llvm/Support/ELF.h"
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2010-11-05 18:48:58 +00:00
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#include "llvm/Support/MachO.h"
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2010-09-30 02:17:26 +00:00
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#include "llvm/Support/ErrorHandling.h"
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#include "llvm/Support/raw_ostream.h"
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#include "llvm/Target/TargetRegistry.h"
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#include "llvm/Target/TargetAsmBackend.h"
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using namespace llvm;
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namespace {
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class ARMAsmBackend : public TargetAsmBackend {
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public:
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ARMAsmBackend(const Target &T)
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2010-09-30 03:21:00 +00:00
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: TargetAsmBackend(T) {
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2010-09-30 02:17:26 +00:00
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}
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bool MayNeedRelaxation(const MCInst &Inst) const;
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void RelaxInstruction(const MCInst &Inst, MCInst &Res) const;
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bool WriteNopData(uint64_t Count, MCObjectWriter *OW) const;
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2010-09-30 17:45:51 +00:00
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unsigned getPointerSize() const {
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return 4;
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}
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2010-09-30 02:17:26 +00:00
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};
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bool ARMAsmBackend::MayNeedRelaxation(const MCInst &Inst) const {
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// FIXME: Thumb targets, different move constant targets..
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return false;
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}
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void ARMAsmBackend::RelaxInstruction(const MCInst &Inst, MCInst &Res) const {
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assert(0 && "ARMAsmBackend::RelaxInstruction() unimplemented");
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return;
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}
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bool ARMAsmBackend::WriteNopData(uint64_t Count, MCObjectWriter *OW) const {
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2010-11-11 23:41:09 +00:00
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// if ((Count % 4) != 0) {
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// // Fixme: % 2 for Thumb?
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// return false;
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// }
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// FIXME: Zero fill for now. That's not right, but at least will get the
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// section size right.
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for (uint64_t i = 0; i != Count; ++i)
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OW->Write8(0);
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2010-10-25 17:50:35 +00:00
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return true;
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2010-09-30 03:20:34 +00:00
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}
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2010-09-30 02:17:26 +00:00
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} // end anonymous namespace
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namespace {
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// FIXME: This should be in a separate file.
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// ELF is an ELF of course...
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class ELFARMAsmBackend : public ARMAsmBackend {
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2010-10-16 18:23:53 +00:00
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MCELFObjectFormat Format;
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2010-09-30 02:17:26 +00:00
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public:
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Triple::OSType OSType;
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ELFARMAsmBackend(const Target &T, Triple::OSType _OSType)
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: ARMAsmBackend(T), OSType(_OSType) {
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HasScatteredSymbols = true;
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}
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2010-10-16 18:23:53 +00:00
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virtual const MCObjectFormat &getObjectFormat() const {
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return Format;
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}
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2010-09-30 02:17:26 +00:00
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void ApplyFixup(const MCFixup &Fixup, MCDataFragment &DF,
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uint64_t Value) const;
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bool isVirtualSection(const MCSection &Section) const {
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const MCSectionELF &SE = static_cast<const MCSectionELF&>(Section);
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return SE.getType() == MCSectionELF::SHT_NOBITS;
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}
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MCObjectWriter *createObjectWriter(raw_ostream &OS) const {
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2010-11-13 07:33:40 +00:00
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return createELFObjectWriter(OS, /*Is64Bit=*/false,
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OSType, ELF::EM_ARM,
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/*IsLittleEndian=*/true,
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/*HasRelocationAddend=*/false);
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2010-09-30 02:17:26 +00:00
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}
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};
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2010-09-30 14:58:19 +00:00
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// Fixme: can we raise this to share code between Darwin and ELF?
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2010-09-30 02:17:26 +00:00
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void ELFARMAsmBackend::ApplyFixup(const MCFixup &Fixup, MCDataFragment &DF,
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uint64_t Value) const {
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assert(0 && "ELFARMAsmBackend::ApplyFixup() unimplemented");
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}
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// FIXME: This should be in a separate file.
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class DarwinARMAsmBackend : public ARMAsmBackend {
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2010-10-16 18:23:53 +00:00
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MCMachOObjectFormat Format;
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2010-09-30 02:17:26 +00:00
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public:
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DarwinARMAsmBackend(const Target &T)
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: ARMAsmBackend(T) {
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HasScatteredSymbols = true;
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}
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2010-10-16 18:23:53 +00:00
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virtual const MCObjectFormat &getObjectFormat() const {
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return Format;
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}
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2010-09-30 02:17:26 +00:00
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void ApplyFixup(const MCFixup &Fixup, MCDataFragment &DF,
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uint64_t Value) const;
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bool isVirtualSection(const MCSection &Section) const {
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const MCSectionMachO &SMO = static_cast<const MCSectionMachO&>(Section);
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return (SMO.getType() == MCSectionMachO::S_ZEROFILL ||
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SMO.getType() == MCSectionMachO::S_GB_ZEROFILL ||
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SMO.getType() == MCSectionMachO::S_THREAD_LOCAL_ZEROFILL);
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}
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MCObjectWriter *createObjectWriter(raw_ostream &OS) const {
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2010-11-05 18:48:58 +00:00
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// FIXME: Subtarget info should be derived. Force v7 for now.
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2010-11-13 07:33:40 +00:00
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return createMachObjectWriter(OS, /*Is64Bit=*/false, MachO::CPUTypeARM,
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MachO::CPUSubType_ARM_V7,
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/*IsLittleEndian=*/true);
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2010-09-30 02:17:26 +00:00
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}
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virtual bool doesSectionRequireSymbols(const MCSection &Section) const {
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return false;
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}
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};
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2010-11-11 18:04:49 +00:00
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static unsigned getFixupKindNumBytes(unsigned Kind) {
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2010-11-09 01:37:15 +00:00
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switch (Kind) {
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default: llvm_unreachable("Unknown fixup kind!");
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2010-11-11 18:04:49 +00:00
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case FK_Data_4: return 4;
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2010-11-09 01:37:15 +00:00
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case ARM::fixup_arm_pcrel_12: return 2;
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case ARM::fixup_arm_vfp_pcrel_12: return 1;
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2010-11-11 18:04:49 +00:00
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case ARM::fixup_arm_branch: return 3;
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2010-11-09 01:37:15 +00:00
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}
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}
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static unsigned adjustFixupValue(unsigned Kind, uint64_t Value) {
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switch (Kind) {
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default:
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llvm_unreachable("Unknown fixup kind!");
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case FK_Data_4:
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2010-11-09 17:36:59 +00:00
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return Value;
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2010-11-09 01:37:15 +00:00
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case ARM::fixup_arm_pcrel_12:
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// ARM PC-relative values are offset by 8.
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return Value - 8;
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2010-11-11 18:04:49 +00:00
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case ARM::fixup_arm_branch:
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2010-11-09 01:37:15 +00:00
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case ARM::fixup_arm_vfp_pcrel_12:
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2010-11-11 18:04:49 +00:00
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// These values don't encode the low two bits since they're always zero.
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// Offset by 8 just as above.
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2010-11-09 01:37:15 +00:00
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return (Value - 8) >> 2;
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}
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}
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2010-09-30 02:17:26 +00:00
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void DarwinARMAsmBackend::ApplyFixup(const MCFixup &Fixup, MCDataFragment &DF,
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2010-11-11 18:04:49 +00:00
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uint64_t Value) const {
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unsigned NumBytes = getFixupKindNumBytes(Fixup.getKind());
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2010-11-09 01:37:15 +00:00
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Value = adjustFixupValue(Fixup.getKind(), Value);
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assert(Fixup.getOffset() + NumBytes <= DF.getContents().size() &&
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"Invalid fixup offset!");
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// For each byte of the fragment that the fixup touches, mask in the
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// bits from the fixup value.
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for (unsigned i = 0; i != NumBytes; ++i)
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DF.getContents()[Fixup.getOffset() + i] |= uint8_t(Value >> (i * 8));
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2010-09-30 02:17:26 +00:00
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}
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2010-09-30 03:21:00 +00:00
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} // end anonymous namespace
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2010-09-30 02:17:26 +00:00
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TargetAsmBackend *llvm::createARMAsmBackend(const Target &T,
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const std::string &TT) {
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switch (Triple(TT).getOS()) {
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case Triple::Darwin:
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return new DarwinARMAsmBackend(T);
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case Triple::MinGW32:
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case Triple::Cygwin:
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case Triple::Win32:
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assert(0 && "Windows not supported on ARM");
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default:
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return new ELFARMAsmBackend(T, Triple(TT).getOS());
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}
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}
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