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llvm-project/llvm/lib/Target/ARM/MCTargetDesc/ARMELFStreamer.cpp

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//===- lib/MC/ARMELFStreamer.cpp - ELF Object Output for ARM --------------===//
//
// 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 ARM ELF .o object files. Different
// from generic ELF streamer in emitting mapping symbols ($a, $t and $d) to
// delimit regions of data and code.
//
//===----------------------------------------------------------------------===//
#include "ARMRegisterInfo.h"
#include "ARMUnwindOpAsm.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/SmallVector.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/MCAsmInfo.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/MCFixup.h"
#include "llvm/MC/MCFragment.h"
#include "llvm/MC/MCInst.h"
#include "llvm/MC/MCInstPrinter.h"
#include "llvm/MC/MCObjectWriter.h"
#include "llvm/MC/MCRegisterInfo.h"
#include "llvm/MC/MCSection.h"
#include "llvm/MC/MCSectionELF.h"
#include "llvm/MC/MCStreamer.h"
#include "llvm/MC/MCSubtargetInfo.h"
#include "llvm/MC/MCSymbol.h"
#include "llvm/MC/MCSymbolELF.h"
#include "llvm/MC/SectionKind.h"
#include "llvm/Support/ARMBuildAttributes.h"
#include "llvm/Support/ARMEHABI.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/FormattedStream.h"
#include "llvm/Support/LEB128.h"
#include "llvm/Support/TargetParser.h"
#include "llvm/Support/raw_ostream.h"
#include <algorithm>
#include <cassert>
#include <climits>
#include <cstddef>
#include <cstdint>
#include <string>
using namespace llvm;
static std::string GetAEABIUnwindPersonalityName(unsigned Index) {
assert(Index < ARM::EHABI::NUM_PERSONALITY_INDEX &&
"Invalid personality index");
return (Twine("__aeabi_unwind_cpp_pr") + Twine(Index)).str();
}
namespace {
class ARMELFStreamer;
class ARMTargetAsmStreamer : public ARMTargetStreamer {
formatted_raw_ostream &OS;
MCInstPrinter &InstPrinter;
bool IsVerboseAsm;
void emitFnStart() override;
void emitFnEnd() override;
void emitCantUnwind() override;
void emitPersonality(const MCSymbol *Personality) override;
void emitPersonalityIndex(unsigned Index) override;
void emitHandlerData() override;
void emitSetFP(unsigned FpReg, unsigned SpReg, int64_t Offset = 0) override;
void emitMovSP(unsigned Reg, int64_t Offset = 0) override;
void emitPad(int64_t Offset) override;
void emitRegSave(const SmallVectorImpl<unsigned> &RegList,
bool isVector) override;
void emitUnwindRaw(int64_t Offset,
const SmallVectorImpl<uint8_t> &Opcodes) override;
void switchVendor(StringRef Vendor) override;
void emitAttribute(unsigned Attribute, unsigned Value) override;
void emitTextAttribute(unsigned Attribute, StringRef String) override;
void emitIntTextAttribute(unsigned Attribute, unsigned IntValue,
StringRef StringValue) override;
void emitArch(ARM::ArchKind Arch) override;
void emitArchExtension(uint64_t ArchExt) override;
void emitObjectArch(ARM::ArchKind Arch) override;
void emitFPU(unsigned FPU) override;
void emitInst(uint32_t Inst, char Suffix = '\0') override;
void finishAttributeSection() override;
void AnnotateTLSDescriptorSequence(const MCSymbolRefExpr *SRE) override;
void emitThumbSet(MCSymbol *Symbol, const MCExpr *Value) override;
public:
ARMTargetAsmStreamer(MCStreamer &S, formatted_raw_ostream &OS,
MCInstPrinter &InstPrinter, bool VerboseAsm);
};
ARMTargetAsmStreamer::ARMTargetAsmStreamer(MCStreamer &S,
formatted_raw_ostream &OS,
MCInstPrinter &InstPrinter,
bool VerboseAsm)
: ARMTargetStreamer(S), OS(OS), InstPrinter(InstPrinter),
IsVerboseAsm(VerboseAsm) {}
void ARMTargetAsmStreamer::emitFnStart() { OS << "\t.fnstart\n"; }
void ARMTargetAsmStreamer::emitFnEnd() { OS << "\t.fnend\n"; }
void ARMTargetAsmStreamer::emitCantUnwind() { OS << "\t.cantunwind\n"; }
void ARMTargetAsmStreamer::emitPersonality(const MCSymbol *Personality) {
OS << "\t.personality " << Personality->getName() << '\n';
}
void ARMTargetAsmStreamer::emitPersonalityIndex(unsigned Index) {
OS << "\t.personalityindex " << Index << '\n';
}
void ARMTargetAsmStreamer::emitHandlerData() { OS << "\t.handlerdata\n"; }
void ARMTargetAsmStreamer::emitSetFP(unsigned FpReg, unsigned SpReg,
int64_t Offset) {
OS << "\t.setfp\t";
InstPrinter.printRegName(OS, FpReg);
OS << ", ";
InstPrinter.printRegName(OS, SpReg);
if (Offset)
OS << ", #" << Offset;
OS << '\n';
}
void ARMTargetAsmStreamer::emitMovSP(unsigned Reg, int64_t Offset) {
assert((Reg != ARM::SP && Reg != ARM::PC) &&
"the operand of .movsp cannot be either sp or pc");
OS << "\t.movsp\t";
InstPrinter.printRegName(OS, Reg);
if (Offset)
OS << ", #" << Offset;
OS << '\n';
}
void ARMTargetAsmStreamer::emitPad(int64_t Offset) {
OS << "\t.pad\t#" << Offset << '\n';
}
void ARMTargetAsmStreamer::emitRegSave(const SmallVectorImpl<unsigned> &RegList,
bool isVector) {
assert(RegList.size() && "RegList should not be empty");
if (isVector)
OS << "\t.vsave\t{";
else
OS << "\t.save\t{";
InstPrinter.printRegName(OS, RegList[0]);
for (unsigned i = 1, e = RegList.size(); i != e; ++i) {
OS << ", ";
InstPrinter.printRegName(OS, RegList[i]);
}
OS << "}\n";
}
void ARMTargetAsmStreamer::switchVendor(StringRef Vendor) {}
void ARMTargetAsmStreamer::emitAttribute(unsigned Attribute, unsigned Value) {
OS << "\t.eabi_attribute\t" << Attribute << ", " << Twine(Value);
if (IsVerboseAsm) {
StringRef Name =
ELFAttrs::attrTypeAsString(Attribute, ARMBuildAttrs::ARMAttributeTags);
if (!Name.empty())
OS << "\t@ " << Name;
}
OS << "\n";
}
void ARMTargetAsmStreamer::emitTextAttribute(unsigned Attribute,
StringRef String) {
switch (Attribute) {
case ARMBuildAttrs::CPU_name:
OS << "\t.cpu\t" << String.lower();
break;
default:
OS << "\t.eabi_attribute\t" << Attribute << ", \"" << String << "\"";
if (IsVerboseAsm) {
StringRef Name = ELFAttrs::attrTypeAsString(
Attribute, ARMBuildAttrs::ARMAttributeTags);
if (!Name.empty())
OS << "\t@ " << Name;
}
break;
}
OS << "\n";
}
void ARMTargetAsmStreamer::emitIntTextAttribute(unsigned Attribute,
unsigned IntValue,
StringRef StringValue) {
switch (Attribute) {
default: llvm_unreachable("unsupported multi-value attribute in asm mode");
case ARMBuildAttrs::compatibility:
OS << "\t.eabi_attribute\t" << Attribute << ", " << IntValue;
if (!StringValue.empty())
OS << ", \"" << StringValue << "\"";
if (IsVerboseAsm)
OS << "\t@ "
<< ELFAttrs::attrTypeAsString(Attribute,
ARMBuildAttrs::ARMAttributeTags);
break;
}
OS << "\n";
}
void ARMTargetAsmStreamer::emitArch(ARM::ArchKind Arch) {
OS << "\t.arch\t" << ARM::getArchName(Arch) << "\n";
}
void ARMTargetAsmStreamer::emitArchExtension(uint64_t ArchExt) {
OS << "\t.arch_extension\t" << ARM::getArchExtName(ArchExt) << "\n";
}
void ARMTargetAsmStreamer::emitObjectArch(ARM::ArchKind Arch) {
OS << "\t.object_arch\t" << ARM::getArchName(Arch) << '\n';
}
void ARMTargetAsmStreamer::emitFPU(unsigned FPU) {
OS << "\t.fpu\t" << ARM::getFPUName(FPU) << "\n";
}
void ARMTargetAsmStreamer::finishAttributeSection() {}
void
ARMTargetAsmStreamer::AnnotateTLSDescriptorSequence(const MCSymbolRefExpr *S) {
OS << "\t.tlsdescseq\t" << S->getSymbol().getName() << "\n";
}
void ARMTargetAsmStreamer::emitThumbSet(MCSymbol *Symbol, const MCExpr *Value) {
const MCAsmInfo *MAI = Streamer.getContext().getAsmInfo();
OS << "\t.thumb_set\t";
Symbol->print(OS, MAI);
OS << ", ";
Value->print(OS, MAI);
OS << '\n';
}
void ARMTargetAsmStreamer::emitInst(uint32_t Inst, char Suffix) {
OS << "\t.inst";
if (Suffix)
OS << "." << Suffix;
OS << "\t0x" << Twine::utohexstr(Inst) << "\n";
}
void ARMTargetAsmStreamer::emitUnwindRaw(int64_t Offset,
const SmallVectorImpl<uint8_t> &Opcodes) {
OS << "\t.unwind_raw " << Offset;
for (SmallVectorImpl<uint8_t>::const_iterator OCI = Opcodes.begin(),
OCE = Opcodes.end();
OCI != OCE; ++OCI)
OS << ", 0x" << Twine::utohexstr(*OCI);
OS << '\n';
}
class ARMTargetELFStreamer : public ARMTargetStreamer {
private:
// This structure holds all attributes, accounting for
// their string/numeric value, so we can later emit them
// in declaration order, keeping all in the same vector
struct AttributeItem {
enum {
HiddenAttribute = 0,
NumericAttribute,
TextAttribute,
NumericAndTextAttributes
} Type;
unsigned Tag;
unsigned IntValue;
std::string StringValue;
static bool LessTag(const AttributeItem &LHS, const AttributeItem &RHS) {
// The conformance tag must be emitted first when serialised
// into an object file. Specifically, the addenda to the ARM ABI
// states that (2.3.7.4):
//
// "To simplify recognition by consumers in the common case of
// claiming conformity for the whole file, this tag should be
// emitted first in a file-scope sub-subsection of the first
// public subsection of the attributes section."
//
// So it is special-cased in this comparison predicate when the
// attributes are sorted in finishAttributeSection().
return (RHS.Tag != ARMBuildAttrs::conformance) &&
((LHS.Tag == ARMBuildAttrs::conformance) || (LHS.Tag < RHS.Tag));
}
};
StringRef CurrentVendor;
unsigned FPU = ARM::FK_INVALID;
ARM::ArchKind Arch = ARM::ArchKind::INVALID;
ARM::ArchKind EmittedArch = ARM::ArchKind::INVALID;
SmallVector<AttributeItem, 64> Contents;
MCSection *AttributeSection = nullptr;
AttributeItem *getAttributeItem(unsigned Attribute) {
for (size_t i = 0; i < Contents.size(); ++i)
if (Contents[i].Tag == Attribute)
return &Contents[i];
return nullptr;
}
void setAttributeItem(unsigned Attribute, unsigned Value,
bool OverwriteExisting) {
// Look for existing attribute item
if (AttributeItem *Item = getAttributeItem(Attribute)) {
if (!OverwriteExisting)
return;
Item->Type = AttributeItem::NumericAttribute;
Item->IntValue = Value;
return;
}
// Create new attribute item
AttributeItem Item = {AttributeItem::NumericAttribute, Attribute, Value,
std::string(StringRef(""))};
Contents.push_back(Item);
}
void setAttributeItem(unsigned Attribute, StringRef Value,
bool OverwriteExisting) {
// Look for existing attribute item
if (AttributeItem *Item = getAttributeItem(Attribute)) {
if (!OverwriteExisting)
return;
Item->Type = AttributeItem::TextAttribute;
Item->StringValue = std::string(Value);
return;
}
// Create new attribute item
AttributeItem Item = {AttributeItem::TextAttribute, Attribute, 0,
std::string(Value)};
Contents.push_back(Item);
}
void setAttributeItems(unsigned Attribute, unsigned IntValue,
StringRef StringValue, bool OverwriteExisting) {
// Look for existing attribute item
if (AttributeItem *Item = getAttributeItem(Attribute)) {
if (!OverwriteExisting)
return;
Item->Type = AttributeItem::NumericAndTextAttributes;
Item->IntValue = IntValue;
Item->StringValue = std::string(StringValue);
return;
}
// Create new attribute item
AttributeItem Item = {AttributeItem::NumericAndTextAttributes, Attribute,
IntValue, std::string(StringValue)};
Contents.push_back(Item);
}
void emitArchDefaultAttributes();
void emitFPUDefaultAttributes();
ARMELFStreamer &getStreamer();
void emitFnStart() override;
void emitFnEnd() override;
void emitCantUnwind() override;
void emitPersonality(const MCSymbol *Personality) override;
void emitPersonalityIndex(unsigned Index) override;
void emitHandlerData() override;
void emitSetFP(unsigned FpReg, unsigned SpReg, int64_t Offset = 0) override;
void emitMovSP(unsigned Reg, int64_t Offset = 0) override;
void emitPad(int64_t Offset) override;
void emitRegSave(const SmallVectorImpl<unsigned> &RegList,
bool isVector) override;
void emitUnwindRaw(int64_t Offset,
const SmallVectorImpl<uint8_t> &Opcodes) override;
void switchVendor(StringRef Vendor) override;
void emitAttribute(unsigned Attribute, unsigned Value) override;
void emitTextAttribute(unsigned Attribute, StringRef String) override;
void emitIntTextAttribute(unsigned Attribute, unsigned IntValue,
StringRef StringValue) override;
void emitArch(ARM::ArchKind Arch) override;
void emitObjectArch(ARM::ArchKind Arch) override;
void emitFPU(unsigned FPU) override;
void emitInst(uint32_t Inst, char Suffix = '\0') override;
void finishAttributeSection() override;
void emitLabel(MCSymbol *Symbol) override;
void AnnotateTLSDescriptorSequence(const MCSymbolRefExpr *SRE) override;
void emitThumbSet(MCSymbol *Symbol, const MCExpr *Value) override;
size_t calculateContentSize() const;
// Reset state between object emissions
void reset() override;
public:
ARMTargetELFStreamer(MCStreamer &S)
: ARMTargetStreamer(S), CurrentVendor("aeabi") {}
};
/// 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
/// ARM ELF ABI: infocenter.arm.com/help/topic/com.arm.../IHI0044D_aaelf.pdf.
///
/// In brief: $a, $t or $d should be emitted at the start of each contiguous
/// region of ARM code, Thumb 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
/// r0, r0, r0" an instruction).
///
/// As a result this system is orthogonal to the DataRegion infrastructure used
/// by MachO. Beware!
class ARMELFStreamer : public MCELFStreamer {
public:
friend class ARMTargetELFStreamer;
ARMELFStreamer(MCContext &Context, std::unique_ptr<MCAsmBackend> TAB,
std::unique_ptr<MCObjectWriter> OW,
std::unique_ptr<MCCodeEmitter> Emitter, bool IsThumb,
bool IsAndroid)
: MCELFStreamer(Context, std::move(TAB), std::move(OW),
std::move(Emitter)),
IsThumb(IsThumb), IsAndroid(IsAndroid) {
EHReset();
}
~ARMELFStreamer() override = default;
void finishImpl() override;
// ARM exception handling directives
void emitFnStart();
void emitFnEnd();
void emitCantUnwind();
void emitPersonality(const MCSymbol *Per);
void emitPersonalityIndex(unsigned index);
void emitHandlerData();
void emitSetFP(unsigned NewFpReg, unsigned NewSpReg, int64_t Offset = 0);
void emitMovSP(unsigned Reg, int64_t Offset = 0);
void emitPad(int64_t Offset);
void emitRegSave(const SmallVectorImpl<unsigned> &RegList, bool isVector);
void emitUnwindRaw(int64_t Offset, const SmallVectorImpl<uint8_t> &Opcodes);
void emitFill(const MCExpr &NumBytes, uint64_t FillValue,
SMLoc Loc) override {
emitDataMappingSymbol();
MCObjectStreamer::emitFill(NumBytes, FillValue, Loc);
}
void changeSection(MCSection *Section, const MCExpr *Subsection) override {
LastMappingSymbols[getCurrentSection().first] = std::move(LastEMSInfo);
MCELFStreamer::changeSection(Section, Subsection);
auto LastMappingSymbol = LastMappingSymbols.find(Section);
if (LastMappingSymbol != LastMappingSymbols.end()) {
LastEMSInfo = std::move(LastMappingSymbol->second);
return;
}
LastEMSInfo.reset(new ElfMappingSymbolInfo(SMLoc(), nullptr, 0));
}
/// 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 {
if (IsThumb)
EmitThumbMappingSymbol();
else
EmitARMMappingSymbol();
MCELFStreamer::emitInstruction(Inst, STI);
}
void emitInst(uint32_t Inst, char Suffix) {
unsigned Size;
char Buffer[4];
const bool LittleEndian = getContext().getAsmInfo()->isLittleEndian();
switch (Suffix) {
case '\0':
Size = 4;
assert(!IsThumb);
EmitARMMappingSymbol();
for (unsigned II = 0, IE = Size; II != IE; II++) {
const unsigned I = LittleEndian ? (Size - II - 1) : II;
Buffer[Size - II - 1] = uint8_t(Inst >> I * CHAR_BIT);
}
break;
case 'n':
case 'w':
Size = (Suffix == 'n' ? 2 : 4);
assert(IsThumb);
EmitThumbMappingSymbol();
// Thumb wide instructions are emitted as a pair of 16-bit words of the
// appropriate endianness.
for (unsigned II = 0, IE = Size; II != IE; II = II + 2) {
const unsigned I0 = LittleEndian ? II + 0 : II + 1;
const unsigned I1 = LittleEndian ? II + 1 : II + 0;
Buffer[Size - II - 2] = uint8_t(Inst >> I0 * CHAR_BIT);
Buffer[Size - II - 1] = uint8_t(Inst >> I1 * CHAR_BIT);
}
break;
default:
llvm_unreachable("Invalid Suffix");
}
MCELFStreamer::emitBytes(StringRef(Buffer, Size));
}
/// This is one of the functions used to emit data into an ELF section, so the
/// ARM streamer overrides it to add the appropriate mapping symbol ($d) if
/// necessary.
void emitBytes(StringRef Data) override {
emitDataMappingSymbol();
MCELFStreamer::emitBytes(Data);
}
void FlushPendingMappingSymbol() {
if (!LastEMSInfo->hasInfo())
return;
ElfMappingSymbolInfo *EMS = LastEMSInfo.get();
EmitMappingSymbol("$d", EMS->Loc, EMS->F, EMS->Offset);
EMS->resetInfo();
}
/// This is one of the functions used to emit data into an ELF section, so the
/// ARM streamer overrides it to add the appropriate mapping symbol ($d) if
/// necessary.
void emitValueImpl(const MCExpr *Value, unsigned Size, SMLoc Loc) override {
if (const MCSymbolRefExpr *SRE = dyn_cast_or_null<MCSymbolRefExpr>(Value)) {
if (SRE->getKind() == MCSymbolRefExpr::VK_ARM_SBREL && !(Size == 4)) {
getContext().reportError(Loc, "relocated expression must be 32-bit");
return;
}
getOrCreateDataFragment();
}
emitDataMappingSymbol();
MCELFStreamer::emitValueImpl(Value, Size, Loc);
}
void emitAssemblerFlag(MCAssemblerFlag Flag) override {
MCELFStreamer::emitAssemblerFlag(Flag);
switch (Flag) {
case MCAF_SyntaxUnified:
return; // no-op here.
case MCAF_Code16:
IsThumb = true;
return; // Change to Thumb mode
case MCAF_Code32:
IsThumb = false;
return; // Change to ARM mode
case MCAF_Code64:
return;
case MCAF_SubsectionsViaSymbols:
return;
}
}
private:
enum ElfMappingSymbol {
EMS_None,
EMS_ARM,
EMS_Thumb,
EMS_Data
};
struct ElfMappingSymbolInfo {
explicit ElfMappingSymbolInfo(SMLoc Loc, MCFragment *F, uint64_t O)
: Loc(Loc), F(F), Offset(O), State(EMS_None) {}
void resetInfo() {
F = nullptr;
Offset = 0;
}
bool hasInfo() { return F != nullptr; }
SMLoc Loc;
MCFragment *F;
uint64_t Offset;
ElfMappingSymbol State;
};
void emitDataMappingSymbol() {
if (LastEMSInfo->State == EMS_Data)
return;
else if (LastEMSInfo->State == EMS_None) {
// This is a tentative symbol, it won't really be emitted until it's
// actually needed.
ElfMappingSymbolInfo *EMS = LastEMSInfo.get();
auto *DF = dyn_cast_or_null<MCDataFragment>(getCurrentFragment());
if (!DF)
return;
EMS->Loc = SMLoc();
EMS->F = getCurrentFragment();
EMS->Offset = DF->getContents().size();
LastEMSInfo->State = EMS_Data;
return;
}
EmitMappingSymbol("$d");
LastEMSInfo->State = EMS_Data;
}
void EmitThumbMappingSymbol() {
if (LastEMSInfo->State == EMS_Thumb)
return;
FlushPendingMappingSymbol();
EmitMappingSymbol("$t");
LastEMSInfo->State = EMS_Thumb;
}
void EmitARMMappingSymbol() {
if (LastEMSInfo->State == EMS_ARM)
return;
FlushPendingMappingSymbol();
EmitMappingSymbol("$a");
LastEMSInfo->State = EMS_ARM;
}
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);
}
void EmitMappingSymbol(StringRef Name, SMLoc Loc, MCFragment *F,
uint64_t Offset) {
auto *Symbol = cast<MCSymbolELF>(getContext().getOrCreateSymbol(
Name + "." + Twine(MappingSymbolCounter++)));
emitLabelAtPos(Symbol, Loc, F, Offset);
Symbol->setType(ELF::STT_NOTYPE);
Symbol->setBinding(ELF::STB_LOCAL);
Symbol->setExternal(false);
}
void emitThumbFunc(MCSymbol *Func) override {
getAssembler().setIsThumbFunc(Func);
emitSymbolAttribute(Func, MCSA_ELF_TypeFunction);
}
// Helper functions for ARM exception handling directives
void EHReset();
// Reset state between object emissions
void reset() override;
void EmitPersonalityFixup(StringRef Name);
void FlushPendingOffset();
void FlushUnwindOpcodes(bool NoHandlerData);
void SwitchToEHSection(StringRef Prefix, unsigned Type, unsigned Flags,
SectionKind Kind, const MCSymbol &Fn);
void SwitchToExTabSection(const MCSymbol &FnStart);
void SwitchToExIdxSection(const MCSymbol &FnStart);
void EmitFixup(const MCExpr *Expr, MCFixupKind Kind);
bool IsThumb;
bool IsAndroid;
int64_t MappingSymbolCounter = 0;
DenseMap<const MCSection *, std::unique_ptr<ElfMappingSymbolInfo>>
LastMappingSymbols;
std::unique_ptr<ElfMappingSymbolInfo> LastEMSInfo;
// ARM Exception Handling Frame Information
MCSymbol *ExTab;
MCSymbol *FnStart;
const MCSymbol *Personality;
unsigned PersonalityIndex;
unsigned FPReg; // Frame pointer register
int64_t FPOffset; // Offset: (final frame pointer) - (initial $sp)
int64_t SPOffset; // Offset: (final $sp) - (initial $sp)
int64_t PendingOffset; // Offset: (final $sp) - (emitted $sp)
bool UsedFP;
bool CantUnwind;
SmallVector<uint8_t, 64> Opcodes;
UnwindOpcodeAssembler UnwindOpAsm;
};
} // end anonymous namespace
ARMELFStreamer &ARMTargetELFStreamer::getStreamer() {
return static_cast<ARMELFStreamer &>(Streamer);
}
void ARMTargetELFStreamer::emitFnStart() { getStreamer().emitFnStart(); }
void ARMTargetELFStreamer::emitFnEnd() { getStreamer().emitFnEnd(); }
void ARMTargetELFStreamer::emitCantUnwind() { getStreamer().emitCantUnwind(); }
void ARMTargetELFStreamer::emitPersonality(const MCSymbol *Personality) {
getStreamer().emitPersonality(Personality);
}
void ARMTargetELFStreamer::emitPersonalityIndex(unsigned Index) {
getStreamer().emitPersonalityIndex(Index);
}
void ARMTargetELFStreamer::emitHandlerData() {
getStreamer().emitHandlerData();
}
void ARMTargetELFStreamer::emitSetFP(unsigned FpReg, unsigned SpReg,
int64_t Offset) {
getStreamer().emitSetFP(FpReg, SpReg, Offset);
}
void ARMTargetELFStreamer::emitMovSP(unsigned Reg, int64_t Offset) {
getStreamer().emitMovSP(Reg, Offset);
}
void ARMTargetELFStreamer::emitPad(int64_t Offset) {
getStreamer().emitPad(Offset);
}
void ARMTargetELFStreamer::emitRegSave(const SmallVectorImpl<unsigned> &RegList,
bool isVector) {
getStreamer().emitRegSave(RegList, isVector);
}
void ARMTargetELFStreamer::emitUnwindRaw(int64_t Offset,
const SmallVectorImpl<uint8_t> &Opcodes) {
getStreamer().emitUnwindRaw(Offset, Opcodes);
}
void ARMTargetELFStreamer::switchVendor(StringRef Vendor) {
assert(!Vendor.empty() && "Vendor cannot be empty.");
if (CurrentVendor == Vendor)
return;
if (!CurrentVendor.empty())
finishAttributeSection();
assert(Contents.empty() &&
".ARM.attributes should be flushed before changing vendor");
CurrentVendor = Vendor;
}
void ARMTargetELFStreamer::emitAttribute(unsigned Attribute, unsigned Value) {
setAttributeItem(Attribute, Value, /* OverwriteExisting= */ true);
}
void ARMTargetELFStreamer::emitTextAttribute(unsigned Attribute,
StringRef Value) {
setAttributeItem(Attribute, Value, /* OverwriteExisting= */ true);
}
void ARMTargetELFStreamer::emitIntTextAttribute(unsigned Attribute,
unsigned IntValue,
StringRef StringValue) {
setAttributeItems(Attribute, IntValue, StringValue,
/* OverwriteExisting= */ true);
}
void ARMTargetELFStreamer::emitArch(ARM::ArchKind Value) {
Arch = Value;
}
void ARMTargetELFStreamer::emitObjectArch(ARM::ArchKind Value) {
EmittedArch = Value;
}
void ARMTargetELFStreamer::emitArchDefaultAttributes() {
using namespace ARMBuildAttrs;
setAttributeItem(CPU_name,
ARM::getCPUAttr(Arch),
false);
if (EmittedArch == ARM::ArchKind::INVALID)
setAttributeItem(CPU_arch,
ARM::getArchAttr(Arch),
false);
else
setAttributeItem(CPU_arch,
ARM::getArchAttr(EmittedArch),
false);
switch (Arch) {
case ARM::ArchKind::ARMV2:
case ARM::ArchKind::ARMV2A:
case ARM::ArchKind::ARMV3:
case ARM::ArchKind::ARMV3M:
case ARM::ArchKind::ARMV4:
setAttributeItem(ARM_ISA_use, Allowed, false);
break;
case ARM::ArchKind::ARMV4T:
case ARM::ArchKind::ARMV5T:
case ARM::ArchKind::ARMV5TE:
case ARM::ArchKind::ARMV6:
setAttributeItem(ARM_ISA_use, Allowed, false);
setAttributeItem(THUMB_ISA_use, Allowed, false);
break;
case ARM::ArchKind::ARMV6T2:
setAttributeItem(ARM_ISA_use, Allowed, false);
setAttributeItem(THUMB_ISA_use, AllowThumb32, false);
break;
case ARM::ArchKind::ARMV6K:
case ARM::ArchKind::ARMV6KZ:
setAttributeItem(ARM_ISA_use, Allowed, false);
setAttributeItem(THUMB_ISA_use, Allowed, false);
setAttributeItem(Virtualization_use, AllowTZ, false);
break;
case ARM::ArchKind::ARMV6M:
setAttributeItem(THUMB_ISA_use, Allowed, false);
break;
case ARM::ArchKind::ARMV7A:
setAttributeItem(CPU_arch_profile, ApplicationProfile, false);
setAttributeItem(ARM_ISA_use, Allowed, false);
setAttributeItem(THUMB_ISA_use, AllowThumb32, false);
break;
case ARM::ArchKind::ARMV7R:
setAttributeItem(CPU_arch_profile, RealTimeProfile, false);
setAttributeItem(ARM_ISA_use, Allowed, false);
setAttributeItem(THUMB_ISA_use, AllowThumb32, false);
break;
case ARM::ArchKind::ARMV7EM:
case ARM::ArchKind::ARMV7M:
setAttributeItem(CPU_arch_profile, MicroControllerProfile, false);
setAttributeItem(THUMB_ISA_use, AllowThumb32, false);
break;
case ARM::ArchKind::ARMV8A:
case ARM::ArchKind::ARMV8_1A:
case ARM::ArchKind::ARMV8_2A:
case ARM::ArchKind::ARMV8_3A:
case ARM::ArchKind::ARMV8_4A:
case ARM::ArchKind::ARMV8_5A:
case ARM::ArchKind::ARMV8_6A:
setAttributeItem(CPU_arch_profile, ApplicationProfile, false);
setAttributeItem(ARM_ISA_use, Allowed, false);
setAttributeItem(THUMB_ISA_use, AllowThumb32, false);
setAttributeItem(MPextension_use, Allowed, false);
setAttributeItem(Virtualization_use, AllowTZVirtualization, false);
break;
case ARM::ArchKind::ARMV8MBaseline:
case ARM::ArchKind::ARMV8MMainline:
setAttributeItem(THUMB_ISA_use, AllowThumbDerived, false);
setAttributeItem(CPU_arch_profile, MicroControllerProfile, false);
break;
case ARM::ArchKind::IWMMXT:
setAttributeItem(ARM_ISA_use, Allowed, false);
setAttributeItem(THUMB_ISA_use, Allowed, false);
setAttributeItem(WMMX_arch, AllowWMMXv1, false);
break;
case ARM::ArchKind::IWMMXT2:
setAttributeItem(ARM_ISA_use, Allowed, false);
setAttributeItem(THUMB_ISA_use, Allowed, false);
setAttributeItem(WMMX_arch, AllowWMMXv2, false);
break;
default:
report_fatal_error("Unknown Arch: " + Twine(ARM::getArchName(Arch)));
break;
}
}
void ARMTargetELFStreamer::emitFPU(unsigned Value) {
FPU = Value;
}
void ARMTargetELFStreamer::emitFPUDefaultAttributes() {
switch (FPU) {
case ARM::FK_VFP:
case ARM::FK_VFPV2:
setAttributeItem(ARMBuildAttrs::FP_arch,
ARMBuildAttrs::AllowFPv2,
/* OverwriteExisting= */ false);
break;
case ARM::FK_VFPV3:
setAttributeItem(ARMBuildAttrs::FP_arch,
ARMBuildAttrs::AllowFPv3A,
/* OverwriteExisting= */ false);
break;
case ARM::FK_VFPV3_FP16:
setAttributeItem(ARMBuildAttrs::FP_arch,
ARMBuildAttrs::AllowFPv3A,
/* OverwriteExisting= */ false);
setAttributeItem(ARMBuildAttrs::FP_HP_extension,
ARMBuildAttrs::AllowHPFP,
/* OverwriteExisting= */ false);
break;
case ARM::FK_VFPV3_D16:
setAttributeItem(ARMBuildAttrs::FP_arch,
ARMBuildAttrs::AllowFPv3B,
/* OverwriteExisting= */ false);
break;
case ARM::FK_VFPV3_D16_FP16:
setAttributeItem(ARMBuildAttrs::FP_arch,
ARMBuildAttrs::AllowFPv3B,
/* OverwriteExisting= */ false);
setAttributeItem(ARMBuildAttrs::FP_HP_extension,
ARMBuildAttrs::AllowHPFP,
/* OverwriteExisting= */ false);
break;
case ARM::FK_VFPV3XD:
setAttributeItem(ARMBuildAttrs::FP_arch,
ARMBuildAttrs::AllowFPv3B,
/* OverwriteExisting= */ false);
break;
case ARM::FK_VFPV3XD_FP16:
setAttributeItem(ARMBuildAttrs::FP_arch,
ARMBuildAttrs::AllowFPv3B,
/* OverwriteExisting= */ false);
setAttributeItem(ARMBuildAttrs::FP_HP_extension,
ARMBuildAttrs::AllowHPFP,
/* OverwriteExisting= */ false);
break;
case ARM::FK_VFPV4:
setAttributeItem(ARMBuildAttrs::FP_arch,
ARMBuildAttrs::AllowFPv4A,
/* OverwriteExisting= */ false);
break;
// ABI_HardFP_use is handled in ARMAsmPrinter, so _SP_D16 is treated the same
// as _D16 here.
case ARM::FK_FPV4_SP_D16:
case ARM::FK_VFPV4_D16:
setAttributeItem(ARMBuildAttrs::FP_arch,
ARMBuildAttrs::AllowFPv4B,
/* OverwriteExisting= */ false);
break;
case ARM::FK_FP_ARMV8:
setAttributeItem(ARMBuildAttrs::FP_arch,
ARMBuildAttrs::AllowFPARMv8A,
/* OverwriteExisting= */ false);
break;
// FPV5_D16 is identical to FP_ARMV8 except for the number of D registers, so
// uses the FP_ARMV8_D16 build attribute.
case ARM::FK_FPV5_SP_D16:
case ARM::FK_FPV5_D16:
setAttributeItem(ARMBuildAttrs::FP_arch,
ARMBuildAttrs::AllowFPARMv8B,
/* OverwriteExisting= */ false);
break;
case ARM::FK_NEON:
setAttributeItem(ARMBuildAttrs::FP_arch,
ARMBuildAttrs::AllowFPv3A,
/* OverwriteExisting= */ false);
setAttributeItem(ARMBuildAttrs::Advanced_SIMD_arch,
ARMBuildAttrs::AllowNeon,
/* OverwriteExisting= */ false);
break;
case ARM::FK_NEON_FP16:
setAttributeItem(ARMBuildAttrs::FP_arch,
ARMBuildAttrs::AllowFPv3A,
/* OverwriteExisting= */ false);
setAttributeItem(ARMBuildAttrs::Advanced_SIMD_arch,
ARMBuildAttrs::AllowNeon,
/* OverwriteExisting= */ false);
setAttributeItem(ARMBuildAttrs::FP_HP_extension,
ARMBuildAttrs::AllowHPFP,
/* OverwriteExisting= */ false);
break;
case ARM::FK_NEON_VFPV4:
setAttributeItem(ARMBuildAttrs::FP_arch,
ARMBuildAttrs::AllowFPv4A,
/* OverwriteExisting= */ false);
setAttributeItem(ARMBuildAttrs::Advanced_SIMD_arch,
ARMBuildAttrs::AllowNeon2,
/* OverwriteExisting= */ false);
break;
case ARM::FK_NEON_FP_ARMV8:
case ARM::FK_CRYPTO_NEON_FP_ARMV8:
setAttributeItem(ARMBuildAttrs::FP_arch,
ARMBuildAttrs::AllowFPARMv8A,
/* OverwriteExisting= */ false);
// 'Advanced_SIMD_arch' must be emitted not here, but within
// ARMAsmPrinter::emitAttributes(), depending on hasV8Ops() and hasV8_1a()
break;
case ARM::FK_SOFTVFP:
case ARM::FK_NONE:
break;
default:
report_fatal_error("Unknown FPU: " + Twine(FPU));
break;
}
}
size_t ARMTargetELFStreamer::calculateContentSize() const {
size_t Result = 0;
for (size_t i = 0; i < Contents.size(); ++i) {
AttributeItem item = Contents[i];
switch (item.Type) {
case AttributeItem::HiddenAttribute:
break;
case AttributeItem::NumericAttribute:
Result += getULEB128Size(item.Tag);
Result += getULEB128Size(item.IntValue);
break;
case AttributeItem::TextAttribute:
Result += getULEB128Size(item.Tag);
Result += item.StringValue.size() + 1; // string + '\0'
break;
case AttributeItem::NumericAndTextAttributes:
Result += getULEB128Size(item.Tag);
Result += getULEB128Size(item.IntValue);
Result += item.StringValue.size() + 1; // string + '\0';
break;
}
}
return Result;
}
void ARMTargetELFStreamer::finishAttributeSection() {
// <format-version>
// [ <section-length> "vendor-name"
// [ <file-tag> <size> <attribute>*
// | <section-tag> <size> <section-number>* 0 <attribute>*
// | <symbol-tag> <size> <symbol-number>* 0 <attribute>*
// ]+
// ]*
if (FPU != ARM::FK_INVALID)
emitFPUDefaultAttributes();
if (Arch != ARM::ArchKind::INVALID)
emitArchDefaultAttributes();
if (Contents.empty())
return;
llvm::sort(Contents, AttributeItem::LessTag);
ARMELFStreamer &Streamer = getStreamer();
// Switch to .ARM.attributes section
if (AttributeSection) {
Streamer.SwitchSection(AttributeSection);
} else {
AttributeSection = Streamer.getContext().getELFSection(
".ARM.attributes", ELF::SHT_ARM_ATTRIBUTES, 0);
Streamer.SwitchSection(AttributeSection);
// Format version
Streamer.emitInt8(0x41);
}
// Vendor size + Vendor name + '\0'
const size_t VendorHeaderSize = 4 + CurrentVendor.size() + 1;
// Tag + Tag Size
const size_t TagHeaderSize = 1 + 4;
const size_t ContentsSize = calculateContentSize();
Streamer.emitInt32(VendorHeaderSize + TagHeaderSize + ContentsSize);
Streamer.emitBytes(CurrentVendor);
Streamer.emitInt8(0); // '\0'
Streamer.emitInt8(ARMBuildAttrs::File);
Streamer.emitInt32(TagHeaderSize + ContentsSize);
// Size should have been accounted for already, now
// emit each field as its type (ULEB or String)
for (size_t i = 0; i < Contents.size(); ++i) {
AttributeItem item = Contents[i];
Streamer.emitULEB128IntValue(item.Tag);
switch (item.Type) {
default: llvm_unreachable("Invalid attribute type");
case AttributeItem::NumericAttribute:
Streamer.emitULEB128IntValue(item.IntValue);
break;
case AttributeItem::TextAttribute:
Streamer.emitBytes(item.StringValue);
Streamer.emitInt8(0); // '\0'
break;
case AttributeItem::NumericAndTextAttributes:
Streamer.emitULEB128IntValue(item.IntValue);
Streamer.emitBytes(item.StringValue);
Streamer.emitInt8(0); // '\0'
break;
}
}
Contents.clear();
FPU = ARM::FK_INVALID;
}
void ARMTargetELFStreamer::emitLabel(MCSymbol *Symbol) {
ARMELFStreamer &Streamer = getStreamer();
if (!Streamer.IsThumb)
return;
Streamer.getAssembler().registerSymbol(*Symbol);
unsigned Type = cast<MCSymbolELF>(Symbol)->getType();
if (Type == ELF::STT_FUNC || Type == ELF::STT_GNU_IFUNC)
Streamer.emitThumbFunc(Symbol);
}
void
ARMTargetELFStreamer::AnnotateTLSDescriptorSequence(const MCSymbolRefExpr *S) {
getStreamer().EmitFixup(S, FK_Data_4);
}
void ARMTargetELFStreamer::emitThumbSet(MCSymbol *Symbol, const MCExpr *Value) {
if (const MCSymbolRefExpr *SRE = dyn_cast<MCSymbolRefExpr>(Value)) {
const MCSymbol &Sym = SRE->getSymbol();
if (!Sym.isDefined()) {
getStreamer().emitAssignment(Symbol, Value);
return;
}
}
getStreamer().emitThumbFunc(Symbol);
getStreamer().emitAssignment(Symbol, Value);
}
void ARMTargetELFStreamer::emitInst(uint32_t Inst, char Suffix) {
getStreamer().emitInst(Inst, Suffix);
}
void ARMTargetELFStreamer::reset() { AttributeSection = nullptr; }
void ARMELFStreamer::finishImpl() {
MCTargetStreamer &TS = *getTargetStreamer();
ARMTargetStreamer &ATS = static_cast<ARMTargetStreamer &>(TS);
ATS.finishAttributeSection();
MCELFStreamer::finishImpl();
}
void ARMELFStreamer::reset() {
MCTargetStreamer &TS = *getTargetStreamer();
ARMTargetStreamer &ATS = static_cast<ARMTargetStreamer &>(TS);
ATS.reset();
MappingSymbolCounter = 0;
MCELFStreamer::reset();
LastMappingSymbols.clear();
LastEMSInfo.reset();
// MCELFStreamer clear's the assembler's e_flags. However, for
// arm we manually set the ABI version on streamer creation, so
// do the same here
getAssembler().setELFHeaderEFlags(ELF::EF_ARM_EABI_VER5);
}
inline void ARMELFStreamer::SwitchToEHSection(StringRef Prefix,
unsigned Type,
unsigned Flags,
SectionKind Kind,
const MCSymbol &Fn) {
const MCSectionELF &FnSection =
static_cast<const MCSectionELF &>(Fn.getSection());
// Create the name for new section
StringRef FnSecName(FnSection.getName());
SmallString<128> EHSecName(Prefix);
if (FnSecName != ".text") {
EHSecName += FnSecName;
}
// Get .ARM.extab or .ARM.exidx section
const MCSymbolELF *Group = FnSection.getGroup();
if (Group)
Flags |= ELF::SHF_GROUP;
MCSectionELF *EHSection = getContext().getELFSection(
EHSecName, Type, Flags, 0, Group, FnSection.getUniqueID(),
static_cast<const MCSymbolELF *>(FnSection.getBeginSymbol()));
assert(EHSection && "Failed to get the required EH section");
// Switch to .ARM.extab or .ARM.exidx section
SwitchSection(EHSection);
emitCodeAlignment(4);
}
inline void ARMELFStreamer::SwitchToExTabSection(const MCSymbol &FnStart) {
SwitchToEHSection(".ARM.extab", ELF::SHT_PROGBITS, ELF::SHF_ALLOC,
SectionKind::getData(), FnStart);
}
inline void ARMELFStreamer::SwitchToExIdxSection(const MCSymbol &FnStart) {
SwitchToEHSection(".ARM.exidx", ELF::SHT_ARM_EXIDX,
ELF::SHF_ALLOC | ELF::SHF_LINK_ORDER,
SectionKind::getData(), FnStart);
}
void ARMELFStreamer::EmitFixup(const MCExpr *Expr, MCFixupKind Kind) {
MCDataFragment *Frag = getOrCreateDataFragment();
Frag->getFixups().push_back(MCFixup::create(Frag->getContents().size(), Expr,
Kind));
}
void ARMELFStreamer::EHReset() {
ExTab = nullptr;
FnStart = nullptr;
Personality = nullptr;
PersonalityIndex = ARM::EHABI::NUM_PERSONALITY_INDEX;
FPReg = ARM::SP;
FPOffset = 0;
SPOffset = 0;
PendingOffset = 0;
UsedFP = false;
CantUnwind = false;
Opcodes.clear();
UnwindOpAsm.Reset();
}
void ARMELFStreamer::emitFnStart() {
assert(FnStart == nullptr);
FnStart = getContext().createTempSymbol();
emitLabel(FnStart);
}
void ARMELFStreamer::emitFnEnd() {
assert(FnStart && ".fnstart must precedes .fnend");
// Emit unwind opcodes if there is no .handlerdata directive
if (!ExTab && !CantUnwind)
FlushUnwindOpcodes(true);
// Emit the exception index table entry
SwitchToExIdxSection(*FnStart);
// The EHABI requires a dependency preserving R_ARM_NONE relocation to the
// personality routine to protect it from an arbitrary platform's static
// linker garbage collection. We disable this for Android where the unwinder
// is either dynamically linked or directly references the personality
// routine.
if (PersonalityIndex < ARM::EHABI::NUM_PERSONALITY_INDEX && !IsAndroid)
EmitPersonalityFixup(GetAEABIUnwindPersonalityName(PersonalityIndex));
const MCSymbolRefExpr *FnStartRef =
MCSymbolRefExpr::create(FnStart,
MCSymbolRefExpr::VK_ARM_PREL31,
getContext());
emitValue(FnStartRef, 4);
if (CantUnwind) {
emitInt32(ARM::EHABI::EXIDX_CANTUNWIND);
} else if (ExTab) {
// Emit a reference to the unwind opcodes in the ".ARM.extab" section.
const MCSymbolRefExpr *ExTabEntryRef =
MCSymbolRefExpr::create(ExTab,
MCSymbolRefExpr::VK_ARM_PREL31,
getContext());
emitValue(ExTabEntryRef, 4);
} else {
// For the __aeabi_unwind_cpp_pr0, we have to emit the unwind opcodes in
// the second word of exception index table entry. The size of the unwind
// opcodes should always be 4 bytes.
assert(PersonalityIndex == ARM::EHABI::AEABI_UNWIND_CPP_PR0 &&
"Compact model must use __aeabi_unwind_cpp_pr0 as personality");
assert(Opcodes.size() == 4u &&
"Unwind opcode size for __aeabi_unwind_cpp_pr0 must be equal to 4");
uint64_t Intval = Opcodes[0] |
Opcodes[1] << 8 |
Opcodes[2] << 16 |
Opcodes[3] << 24;
emitIntValue(Intval, Opcodes.size());
}
// Switch to the section containing FnStart
SwitchSection(&FnStart->getSection());
// Clean exception handling frame information
EHReset();
}
void ARMELFStreamer::emitCantUnwind() { CantUnwind = true; }
// Add the R_ARM_NONE fixup at the same position
void ARMELFStreamer::EmitPersonalityFixup(StringRef Name) {
const MCSymbol *PersonalitySym = getContext().getOrCreateSymbol(Name);
const MCSymbolRefExpr *PersonalityRef = MCSymbolRefExpr::create(
PersonalitySym, MCSymbolRefExpr::VK_ARM_NONE, getContext());
visitUsedExpr(*PersonalityRef);
MCDataFragment *DF = getOrCreateDataFragment();
DF->getFixups().push_back(MCFixup::create(DF->getContents().size(),
PersonalityRef,
MCFixup::getKindForSize(4, false)));
}
void ARMELFStreamer::FlushPendingOffset() {
if (PendingOffset != 0) {
UnwindOpAsm.EmitSPOffset(-PendingOffset);
PendingOffset = 0;
}
}
void ARMELFStreamer::FlushUnwindOpcodes(bool NoHandlerData) {
// Emit the unwind opcode to restore $sp.
if (UsedFP) {
const MCRegisterInfo *MRI = getContext().getRegisterInfo();
int64_t LastRegSaveSPOffset = SPOffset - PendingOffset;
UnwindOpAsm.EmitSPOffset(LastRegSaveSPOffset - FPOffset);
UnwindOpAsm.EmitSetSP(MRI->getEncodingValue(FPReg));
} else {
FlushPendingOffset();
}
// Finalize the unwind opcode sequence
UnwindOpAsm.Finalize(PersonalityIndex, Opcodes);
// For compact model 0, we have to emit the unwind opcodes in the .ARM.exidx
// section. Thus, we don't have to create an entry in the .ARM.extab
// section.
if (NoHandlerData && PersonalityIndex == ARM::EHABI::AEABI_UNWIND_CPP_PR0)
return;
// Switch to .ARM.extab section.
SwitchToExTabSection(*FnStart);
// Create .ARM.extab label for offset in .ARM.exidx
assert(!ExTab);
ExTab = getContext().createTempSymbol();
emitLabel(ExTab);
// Emit personality
if (Personality) {
const MCSymbolRefExpr *PersonalityRef =
MCSymbolRefExpr::create(Personality,
MCSymbolRefExpr::VK_ARM_PREL31,
getContext());
emitValue(PersonalityRef, 4);
}
// Emit unwind opcodes
assert((Opcodes.size() % 4) == 0 &&
"Unwind opcode size for __aeabi_cpp_unwind_pr0 must be multiple of 4");
for (unsigned I = 0; I != Opcodes.size(); I += 4) {
uint64_t Intval = Opcodes[I] |
Opcodes[I + 1] << 8 |
Opcodes[I + 2] << 16 |
Opcodes[I + 3] << 24;
emitInt32(Intval);
}
// According to ARM EHABI section 9.2, if the __aeabi_unwind_cpp_pr1() or
// __aeabi_unwind_cpp_pr2() is used, then the handler data must be emitted
// after the unwind opcodes. The handler data consists of several 32-bit
// words, and should be terminated by zero.
//
// In case that the .handlerdata directive is not specified by the
// programmer, we should emit zero to terminate the handler data.
if (NoHandlerData && !Personality)
emitInt32(0);
}
void ARMELFStreamer::emitHandlerData() { FlushUnwindOpcodes(false); }
void ARMELFStreamer::emitPersonality(const MCSymbol *Per) {
Personality = Per;
UnwindOpAsm.setPersonality(Per);
}
void ARMELFStreamer::emitPersonalityIndex(unsigned Index) {
assert(Index < ARM::EHABI::NUM_PERSONALITY_INDEX && "invalid index");
PersonalityIndex = Index;
}
void ARMELFStreamer::emitSetFP(unsigned NewFPReg, unsigned NewSPReg,
int64_t Offset) {
assert((NewSPReg == ARM::SP || NewSPReg == FPReg) &&
"the operand of .setfp directive should be either $sp or $fp");
UsedFP = true;
FPReg = NewFPReg;
if (NewSPReg == ARM::SP)
FPOffset = SPOffset + Offset;
else
FPOffset += Offset;
}
void ARMELFStreamer::emitMovSP(unsigned Reg, int64_t Offset) {
assert((Reg != ARM::SP && Reg != ARM::PC) &&
"the operand of .movsp cannot be either sp or pc");
assert(FPReg == ARM::SP && "current FP must be SP");
FlushPendingOffset();
FPReg = Reg;
FPOffset = SPOffset + Offset;
const MCRegisterInfo *MRI = getContext().getRegisterInfo();
UnwindOpAsm.EmitSetSP(MRI->getEncodingValue(FPReg));
}
void ARMELFStreamer::emitPad(int64_t Offset) {
// Track the change of the $sp offset
SPOffset -= Offset;
// To squash multiple .pad directives, we should delay the unwind opcode
// until the .save, .vsave, .handlerdata, or .fnend directives.
PendingOffset -= Offset;
}
void ARMELFStreamer::emitRegSave(const SmallVectorImpl<unsigned> &RegList,
bool IsVector) {
// Collect the registers in the register list
unsigned Count = 0;
uint32_t Mask = 0;
const MCRegisterInfo *MRI = getContext().getRegisterInfo();
for (size_t i = 0; i < RegList.size(); ++i) {
unsigned Reg = MRI->getEncodingValue(RegList[i]);
assert(Reg < (IsVector ? 32U : 16U) && "Register out of range");
unsigned Bit = (1u << Reg);
if ((Mask & Bit) == 0) {
Mask |= Bit;
++Count;
}
}
// Track the change the $sp offset: For the .save directive, the
// corresponding push instruction will decrease the $sp by (4 * Count).
// For the .vsave directive, the corresponding vpush instruction will
// decrease $sp by (8 * Count).
SPOffset -= Count * (IsVector ? 8 : 4);
// Emit the opcode
FlushPendingOffset();
if (IsVector)
UnwindOpAsm.EmitVFPRegSave(Mask);
else
UnwindOpAsm.EmitRegSave(Mask);
}
void ARMELFStreamer::emitUnwindRaw(int64_t Offset,
const SmallVectorImpl<uint8_t> &Opcodes) {
FlushPendingOffset();
SPOffset = SPOffset - Offset;
UnwindOpAsm.EmitRaw(Opcodes);
}
namespace llvm {
MCTargetStreamer *createARMTargetAsmStreamer(MCStreamer &S,
formatted_raw_ostream &OS,
MCInstPrinter *InstPrint,
bool isVerboseAsm) {
return new ARMTargetAsmStreamer(S, OS, *InstPrint, isVerboseAsm);
}
MCTargetStreamer *createARMNullTargetStreamer(MCStreamer &S) {
return new ARMTargetStreamer(S);
}
MCTargetStreamer *createARMObjectTargetStreamer(MCStreamer &S,
const MCSubtargetInfo &STI) {
const Triple &TT = STI.getTargetTriple();
if (TT.isOSBinFormatELF())
return new ARMTargetELFStreamer(S);
return new ARMTargetStreamer(S);
}
MCELFStreamer *createARMELFStreamer(MCContext &Context,
std::unique_ptr<MCAsmBackend> TAB,
std::unique_ptr<MCObjectWriter> OW,
std::unique_ptr<MCCodeEmitter> Emitter,
bool RelaxAll, bool IsThumb,
bool IsAndroid) {
ARMELFStreamer *S =
new ARMELFStreamer(Context, std::move(TAB), std::move(OW),
std::move(Emitter), IsThumb, IsAndroid);
// FIXME: This should eventually end up somewhere else where more
// intelligent flag decisions can be made. For now we are just maintaining
// the status quo for ARM and setting EF_ARM_EABI_VER5 as the default.
S->getAssembler().setELFHeaderEFlags(ELF::EF_ARM_EABI_VER5);
if (RelaxAll)
S->getAssembler().setRelaxAll(true);
return S;
}
} // end namespace llvm
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