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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 --------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// 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 "ARMBuildAttrs.h"
#include "ARMArchName.h"
#include "ARMFPUName.h"
#include "ARMRegisterInfo.h"
#include "ARMUnwindOp.h"
#include "ARMUnwindOpAsm.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/ADT/Twine.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/MCELF.h"
#include "llvm/MC/MCELFStreamer.h"
#include "llvm/MC/MCELFSymbolFlags.h"
#include "llvm/MC/MCExpr.h"
#include "llvm/MC/MCInst.h"
#include "llvm/MC/MCInstPrinter.h"
#include "llvm/MC/MCObjectStreamer.h"
#include "llvm/MC/MCRegisterInfo.h"
#include "llvm/MC/MCSection.h"
#include "llvm/MC/MCSectionELF.h"
#include "llvm/MC/MCStreamer.h"
#include "llvm/MC/MCSymbol.h"
#include "llvm/MC/MCValue.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/ELF.h"
#include "llvm/Support/FormattedStream.h"
#include "llvm/Support/raw_ostream.h"
#include <algorithm>
using namespace llvm;
static std::string GetAEABIUnwindPersonalityName(unsigned Index) {
assert(Index < NUM_PERSONALITY_INDEX && "Invalid personality index");
return (Twine("__aeabi_unwind_cpp_pr") + Twine(Index)).str();
}
static const char *GetFPUName(unsigned ID) {
switch (ID) {
default:
llvm_unreachable("Unknown FPU kind");
break;
#define ARM_FPU_NAME(NAME, ID) case ARM::ID: return NAME;
#include "ARMFPUName.def"
}
return NULL;
}
static const char *GetArchName(unsigned ID) {
switch (ID) {
default:
llvm_unreachable("Unknown ARCH kind");
break;
#define ARM_ARCH_NAME(NAME, ID, DEFAULT_CPU_NAME, DEFAULT_CPU_ARCH) \
case ARM::ID: return NAME;
#define ARM_ARCH_ALIAS(NAME, ID) /* empty */
#include "ARMArchName.def"
}
return NULL;
}
static const char *GetArchDefaultCPUName(unsigned ID) {
switch (ID) {
default:
llvm_unreachable("Unknown ARCH kind");
break;
#define ARM_ARCH_NAME(NAME, ID, DEFAULT_CPU_NAME, DEFAULT_CPU_ARCH) \
case ARM::ID: return DEFAULT_CPU_NAME;
#define ARM_ARCH_ALIAS(NAME, ID) /* empty */
#include "ARMArchName.def"
}
return NULL;
}
static unsigned GetArchDefaultCPUArch(unsigned ID) {
switch (ID) {
default:
llvm_unreachable("Unknown ARCH kind");
break;
#define ARM_ARCH_NAME(NAME, ID, DEFAULT_CPU_NAME, DEFAULT_CPU_ARCH) \
case ARM::ID: return ARMBuildAttrs::DEFAULT_CPU_ARCH;
#define ARM_ARCH_ALIAS(NAME, ID) /* empty */
#include "ARMArchName.def"
}
return 0;
}
namespace {
class ARMELFStreamer;
class ARMTargetAsmStreamer : public ARMTargetStreamer {
formatted_raw_ostream &OS;
MCInstPrinter &InstPrinter;
virtual void emitFnStart();
virtual void emitFnEnd();
virtual void emitCantUnwind();
virtual void emitPersonality(const MCSymbol *Personality);
virtual void emitHandlerData();
virtual void emitSetFP(unsigned FpReg, unsigned SpReg, int64_t Offset = 0);
virtual void emitPad(int64_t Offset);
virtual void emitRegSave(const SmallVectorImpl<unsigned> &RegList,
bool isVector);
virtual void switchVendor(StringRef Vendor);
virtual void emitAttribute(unsigned Attribute, unsigned Value);
virtual void emitTextAttribute(unsigned Attribute, StringRef String);
virtual void emitArch(unsigned Arch);
virtual void emitFPU(unsigned FPU);
virtual void emitInst(uint32_t Inst, char Suffix = '\0');
virtual void finishAttributeSection();
public:
ARMTargetAsmStreamer(formatted_raw_ostream &OS, MCInstPrinter &InstPrinter);
};
ARMTargetAsmStreamer::ARMTargetAsmStreamer(formatted_raw_ostream &OS,
MCInstPrinter &InstPrinter)
: OS(OS), InstPrinter(InstPrinter) {}
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::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::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) << "\n";
}
void ARMTargetAsmStreamer::emitTextAttribute(unsigned Attribute,
StringRef String) {
switch (Attribute) {
default: llvm_unreachable("Unsupported Text attribute in ASM Mode");
case ARMBuildAttrs::CPU_name:
OS << "\t.cpu\t" << String.lower() << "\n";
break;
}
}
void ARMTargetAsmStreamer::emitArch(unsigned Arch) {
OS << "\t.arch\t" << GetArchName(Arch) << "\n";
}
void ARMTargetAsmStreamer::emitFPU(unsigned FPU) {
OS << "\t.fpu\t" << GetFPUName(FPU) << "\n";
}
void ARMTargetAsmStreamer::finishAttributeSection() {
}
void ARMTargetAsmStreamer::emitInst(uint32_t Inst, char Suffix) {
OS << "\t.inst";
if (Suffix)
OS << "." << Suffix;
OS << "\t0x" << utohexstr(Inst) << "\n";
}
class ARMTargetELFStreamer : public ARMTargetStreamer {
private:
// This structure holds all attributes, accounting for
// their string/numeric value, so we can later emmit them
// in declaration order, keeping all in the same vector
struct AttributeItem {
enum {
HiddenAttribute = 0,
NumericAttribute,
TextAttribute
} Type;
unsigned Tag;
unsigned IntValue;
StringRef StringValue;
static bool LessTag(const AttributeItem &LHS, const AttributeItem &RHS) {
return (LHS.Tag < RHS.Tag);
}
};
StringRef CurrentVendor;
unsigned FPU;
unsigned Arch;
SmallVector<AttributeItem, 64> Contents;
const MCSection *AttributeSection;
// FIXME: this should be in a more generic place, but
// getULEBSize() is in MCAsmInfo and will be moved to MCDwarf
static size_t getULEBSize(int Value) {
size_t Size = 0;
do {
Value >>= 7;
Size += sizeof(int8_t); // Is this really necessary?
} while (Value);
return Size;
}
AttributeItem *getAttributeItem(unsigned Attribute) {
for (size_t i = 0; i < Contents.size(); ++i)
if (Contents[i].Tag == Attribute)
return &Contents[i];
return 0;
}
void setAttributeItem(unsigned Attribute, unsigned Value,
bool OverwriteExisting) {
// Look for existing attribute item
if (AttributeItem *Item = getAttributeItem(Attribute)) {
if (!OverwriteExisting)
return;
Item->IntValue = Value;
return;
}
// Create new attribute item
AttributeItem Item = {
AttributeItem::NumericAttribute,
Attribute,
Value,
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->StringValue = Value;
return;
}
// Create new attribute item
AttributeItem Item = {
AttributeItem::TextAttribute,
Attribute,
0,
Value
};
Contents.push_back(Item);
}
void emitArchDefaultAttributes();
void emitFPUDefaultAttributes();
ARMELFStreamer &getStreamer();
virtual void emitFnStart();
virtual void emitFnEnd();
virtual void emitCantUnwind();
virtual void emitPersonality(const MCSymbol *Personality);
virtual void emitHandlerData();
virtual void emitSetFP(unsigned FpReg, unsigned SpReg, int64_t Offset = 0);
virtual void emitPad(int64_t Offset);
virtual void emitRegSave(const SmallVectorImpl<unsigned> &RegList,
bool isVector);
virtual void switchVendor(StringRef Vendor);
virtual void emitAttribute(unsigned Attribute, unsigned Value);
virtual void emitTextAttribute(unsigned Attribute, StringRef String);
virtual void emitArch(unsigned Arch);
virtual void emitFPU(unsigned FPU);
virtual void emitInst(uint32_t Inst, char Suffix = '\0');
virtual void finishAttributeSection();
size_t calculateContentSize() const;
public:
ARMTargetELFStreamer()
: ARMTargetStreamer(), CurrentVendor("aeabi"), FPU(ARM::INVALID_FPU),
Arch(ARM::INVALID_ARCH), AttributeSection(0) {
}
};
/// 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, MCTargetStreamer *TargetStreamer,
MCAsmBackend &TAB, raw_ostream &OS, MCCodeEmitter *Emitter,
bool IsThumb)
: MCELFStreamer(Context, TargetStreamer, TAB, OS, Emitter),
IsThumb(IsThumb), MappingSymbolCounter(0), LastEMS(EMS_None) {
Reset();
}
~ARMELFStreamer() {}
virtual void FinishImpl();
// ARM exception handling directives
void emitFnStart();
void emitFnEnd();
void emitCantUnwind();
void emitPersonality(const MCSymbol *Per);
void emitHandlerData();
void emitSetFP(unsigned NewFpReg, unsigned NewSpReg, int64_t Offset = 0);
void emitPad(int64_t Offset);
void emitRegSave(const SmallVectorImpl<unsigned> &RegList, bool isVector);
virtual void ChangeSection(const MCSection *Section,
const MCExpr *Subsection) {
// 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);
}
/// 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.
virtual void EmitInstruction(const MCInst& Inst) {
if (IsThumb)
EmitThumbMappingSymbol();
else
EmitARMMappingSymbol();
MCELFStreamer::EmitInstruction(Inst);
}
virtual 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();
for (unsigned II = 0, IE = Size; II != IE; II = II + 2) {
const unsigned I0 = LittleEndian ? II + 0 : (Size - II - 1);
const unsigned I1 = LittleEndian ? II + 1 : (Size - II - 2);
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.
virtual void EmitBytes(StringRef Data) {
EmitDataMappingSymbol();
MCELFStreamer::EmitBytes(Data);
}
/// 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 ($d) if
/// necessary.
virtual void EmitValueImpl(const MCExpr *Value, unsigned Size) {
EmitDataMappingSymbol();
MCELFStreamer::EmitValueImpl(Value, Size);
}
virtual void EmitAssemblerFlag(MCAssemblerFlag Flag) {
MCELFStreamer::EmitAssemblerFlag(Flag);
switch (Flag) {
case MCAF_SyntaxUnified:
return; // no-op here.
case MCAF_Code16:
IsThumb = true;
return; // Change to Thumb mode
case MCAF_Code32:
IsThumb = false;
return; // Change to ARM mode
case MCAF_Code64:
return;
case MCAF_SubsectionsViaSymbols:
return;
}
}
private:
enum ElfMappingSymbol {
EMS_None,
EMS_ARM,
EMS_Thumb,
EMS_Data
};
void EmitDataMappingSymbol() {
if (LastEMS == EMS_Data) return;
EmitMappingSymbol("$d");
LastEMS = EMS_Data;
}
void EmitThumbMappingSymbol() {
if (LastEMS == EMS_Thumb) return;
EmitMappingSymbol("$t");
LastEMS = EMS_Thumb;
}
void EmitARMMappingSymbol() {
if (LastEMS == EMS_ARM) return;
EmitMappingSymbol("$a");
LastEMS = EMS_ARM;
}
void EmitMappingSymbol(StringRef Name) {
MCSymbol *Start = getContext().CreateTempSymbol();
EmitLabel(Start);
MCSymbol *Symbol =
getContext().GetOrCreateSymbol(Name + "." +
Twine(MappingSymbolCounter++));
MCSymbolData &SD = getAssembler().getOrCreateSymbolData(*Symbol);
MCELF::SetType(SD, ELF::STT_NOTYPE);
MCELF::SetBinding(SD, ELF::STB_LOCAL);
SD.setExternal(false);
AssignSection(Symbol, getCurrentSection().first);
const MCExpr *Value = MCSymbolRefExpr::Create(Start, getContext());
Symbol->setVariableValue(Value);
}
void EmitThumbFunc(MCSymbol *Func) {
// FIXME: Anything needed here to flag the function as thumb?
getAssembler().setIsThumbFunc(Func);
MCSymbolData &SD = getAssembler().getOrCreateSymbolData(*Func);
SD.setFlags(SD.getFlags() | ELF_Other_ThumbFunc);
}
// Helper functions for ARM exception handling directives
void Reset();
void EmitPersonalityFixup(StringRef Name);
void FlushPendingOffset();
void FlushUnwindOpcodes(bool NoHandlerData);
void SwitchToEHSection(const char *Prefix, unsigned Type, unsigned Flags,
SectionKind Kind, const MCSymbol &Fn);
void SwitchToExTabSection(const MCSymbol &FnStart);
void SwitchToExIdxSection(const MCSymbol &FnStart);
bool IsThumb;
int64_t MappingSymbolCounter;
DenseMap<const MCSection *, ElfMappingSymbol> LastMappingSymbols;
ElfMappingSymbol LastEMS;
// 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() {
ARMELFStreamer *S = static_cast<ARMELFStreamer *>(Streamer);
return *S;
}
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::emitHandlerData() {
getStreamer().emitHandlerData();
}
void ARMTargetELFStreamer::emitSetFP(unsigned FpReg, unsigned SpReg,
int64_t Offset) {
getStreamer().emitSetFP(FpReg, SpReg, 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::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::emitArch(unsigned Value) {
Arch = Value;
}
void ARMTargetELFStreamer::emitArchDefaultAttributes() {
using namespace ARMBuildAttrs;
setAttributeItem(CPU_name, GetArchDefaultCPUName(Arch), false);
setAttributeItem(CPU_arch, GetArchDefaultCPUArch(Arch), false);
switch (Arch) {
case ARM::ARMV2:
case ARM::ARMV2A:
case ARM::ARMV3:
case ARM::ARMV3M:
case ARM::ARMV4:
case ARM::ARMV5:
setAttributeItem(ARM_ISA_use, Allowed, false);
break;
case ARM::ARMV4T:
case ARM::ARMV5T:
case ARM::ARMV5TE:
case ARM::ARMV6:
case ARM::ARMV6J:
setAttributeItem(ARM_ISA_use, Allowed, false);
setAttributeItem(THUMB_ISA_use, Allowed, false);
break;
case ARM::ARMV6T2:
setAttributeItem(ARM_ISA_use, Allowed, false);
setAttributeItem(THUMB_ISA_use, AllowThumb32, false);
break;
case ARM::ARMV6Z:
case ARM::ARMV6ZK:
setAttributeItem(ARM_ISA_use, Allowed, false);
setAttributeItem(THUMB_ISA_use, Allowed, false);
setAttributeItem(Virtualization_use, AllowTZ, false);
break;
case ARM::ARMV6M:
setAttributeItem(CPU_arch_profile, MicroControllerProfile, false);
setAttributeItem(THUMB_ISA_use, Allowed, false);
break;
case ARM::ARMV7:
setAttributeItem(THUMB_ISA_use, AllowThumb32, false);
break;
case ARM::ARMV7A:
setAttributeItem(CPU_arch_profile, ApplicationProfile, false);
setAttributeItem(ARM_ISA_use, Allowed, false);
setAttributeItem(THUMB_ISA_use, AllowThumb32, false);
break;
case ARM::ARMV7R:
setAttributeItem(CPU_arch_profile, RealTimeProfile, false);
setAttributeItem(ARM_ISA_use, Allowed, false);
setAttributeItem(THUMB_ISA_use, AllowThumb32, false);
break;
case ARM::ARMV7M:
setAttributeItem(CPU_arch_profile, MicroControllerProfile, false);
setAttributeItem(THUMB_ISA_use, AllowThumb32, false);
break;
case ARM::ARMV8A:
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::IWMMXT:
setAttributeItem(ARM_ISA_use, Allowed, false);
setAttributeItem(THUMB_ISA_use, Allowed, false);
setAttributeItem(WMMX_arch, AllowWMMXv1, false);
break;
case ARM::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(Arch));
break;
}
}
void ARMTargetELFStreamer::emitFPU(unsigned Value) {
FPU = Value;
}
void ARMTargetELFStreamer::emitFPUDefaultAttributes() {
switch (FPU) {
case ARM::VFP:
case ARM::VFPV2:
setAttributeItem(ARMBuildAttrs::FP_arch,
ARMBuildAttrs::AllowFPv2,
/* OverwriteExisting= */ false);
break;
case ARM::VFPV3:
setAttributeItem(ARMBuildAttrs::FP_arch,
ARMBuildAttrs::AllowFPv3A,
/* OverwriteExisting= */ false);
break;
case ARM::VFPV3_D16:
setAttributeItem(ARMBuildAttrs::FP_arch,
ARMBuildAttrs::AllowFPv3B,
/* OverwriteExisting= */ false);
break;
case ARM::VFPV4:
setAttributeItem(ARMBuildAttrs::FP_arch,
ARMBuildAttrs::AllowFPv4A,
/* OverwriteExisting= */ false);
break;
case ARM::VFPV4_D16:
setAttributeItem(ARMBuildAttrs::FP_arch,
ARMBuildAttrs::AllowFPv4B,
/* OverwriteExisting= */ false);
break;
case ARM::FP_ARMV8:
setAttributeItem(ARMBuildAttrs::FP_arch,
ARMBuildAttrs::AllowFPARMv8A,
/* OverwriteExisting= */ false);
break;
case ARM::NEON:
setAttributeItem(ARMBuildAttrs::FP_arch,
ARMBuildAttrs::AllowFPv3A,
/* OverwriteExisting= */ false);
setAttributeItem(ARMBuildAttrs::Advanced_SIMD_arch,
ARMBuildAttrs::AllowNeon,
/* OverwriteExisting= */ false);
break;
case ARM::NEON_VFPV4:
setAttributeItem(ARMBuildAttrs::FP_arch,
ARMBuildAttrs::AllowFPv4A,
/* OverwriteExisting= */ false);
setAttributeItem(ARMBuildAttrs::Advanced_SIMD_arch,
ARMBuildAttrs::AllowNeon2,
/* OverwriteExisting= */ false);
break;
case ARM::NEON_FP_ARMV8:
case ARM::CRYPTO_NEON_FP_ARMV8:
setAttributeItem(ARMBuildAttrs::FP_arch,
ARMBuildAttrs::AllowFPARMv8A,
/* OverwriteExisting= */ false);
setAttributeItem(ARMBuildAttrs::Advanced_SIMD_arch,
ARMBuildAttrs::AllowNeonARMv8,
/* OverwriteExisting= */ false);
break;
case ARM::SOFTVFP:
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 += getULEBSize(item.Tag);
Result += getULEBSize(item.IntValue);
break;
case AttributeItem::TextAttribute:
Result += getULEBSize(item.Tag);
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::INVALID_FPU)
emitFPUDefaultAttributes();
if (Arch != ARM::INVALID_ARCH)
emitArchDefaultAttributes();
if (Contents.empty())
return;
std::sort(Contents.begin(), Contents.end(), 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,
SectionKind::getMetadata());
Streamer.SwitchSection(AttributeSection);
// Format version
Streamer.EmitIntValue(0x41, 1);
}
// 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.EmitIntValue(VendorHeaderSize + TagHeaderSize + ContentsSize, 4);
Streamer.EmitBytes(CurrentVendor);
Streamer.EmitIntValue(0, 1); // '\0'
Streamer.EmitIntValue(ARMBuildAttrs::File, 1);
Streamer.EmitIntValue(TagHeaderSize + ContentsSize, 4);
// 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.upper());
Streamer.EmitIntValue(0, 1); // '\0'
break;
}
}
Contents.clear();
FPU = ARM::INVALID_FPU;
}
void ARMTargetELFStreamer::emitInst(uint32_t Inst, char Suffix) {
getStreamer().emitInst(Inst, Suffix);
}
void ARMELFStreamer::FinishImpl() {
MCTargetStreamer &TS = getTargetStreamer();
ARMTargetStreamer &ATS = static_cast<ARMTargetStreamer &>(TS);
ATS.finishAttributeSection();
MCELFStreamer::FinishImpl();
}
inline void ARMELFStreamer::SwitchToEHSection(const char *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.getSectionName());
SmallString<128> EHSecName(Prefix);
if (FnSecName != ".text") {
EHSecName += FnSecName;
}
// Get .ARM.extab or .ARM.exidx section
const MCSectionELF *EHSection = NULL;
if (const MCSymbol *Group = FnSection.getGroup()) {
EHSection = getContext().getELFSection(
EHSecName, Type, Flags | ELF::SHF_GROUP, Kind,
FnSection.getEntrySize(), Group->getName());
} else {
EHSection = getContext().getELFSection(EHSecName, Type, Flags, Kind);
}
assert(EHSection && "Failed to get the required EH section");
// Switch to .ARM.extab or .ARM.exidx section
SwitchSection(EHSection);
EmitCodeAlignment(4, 0);
}
inline void ARMELFStreamer::SwitchToExTabSection(const MCSymbol &FnStart) {
SwitchToEHSection(".ARM.extab",
ELF::SHT_PROGBITS,
ELF::SHF_ALLOC,
SectionKind::getDataRel(),
FnStart);
}
inline void ARMELFStreamer::SwitchToExIdxSection(const MCSymbol &FnStart) {
SwitchToEHSection(".ARM.exidx",
ELF::SHT_ARM_EXIDX,
ELF::SHF_ALLOC | ELF::SHF_LINK_ORDER,
SectionKind::getDataRel(),
FnStart);
}
void ARMELFStreamer::Reset() {
ExTab = NULL;
FnStart = NULL;
Personality = NULL;
PersonalityIndex = 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 == 0);
FnStart = getContext().CreateTempSymbol();
EmitLabel(FnStart);
}
void ARMELFStreamer::emitFnEnd() {
assert(FnStart && ".fnstart must preceeds .fnend");
// Emit unwind opcodes if there is no .handlerdata directive
if (!ExTab && !CantUnwind)
FlushUnwindOpcodes(true);
// Emit the exception index table entry
SwitchToExIdxSection(*FnStart);
if (PersonalityIndex < NUM_PERSONALITY_INDEX)
EmitPersonalityFixup(GetAEABIUnwindPersonalityName(PersonalityIndex));
const MCSymbolRefExpr *FnStartRef =
MCSymbolRefExpr::Create(FnStart,
MCSymbolRefExpr::VK_ARM_PREL31,
getContext());
EmitValue(FnStartRef, 4);
if (CantUnwind) {
EmitIntValue(EXIDX_CANTUNWIND, 4);
} 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 == AEABI_UNWIND_CPP_PR0 &&
"Compact model must use __aeabi_cpp_unwind_pr0 as personality");
assert(Opcodes.size() == 4u &&
"Unwind opcode size for __aeabi_cpp_unwind_pr0 must be equal to 4");
EmitBytes(StringRef(reinterpret_cast<const char*>(Opcodes.data()),
Opcodes.size()));
}
// Switch to the section containing FnStart
SwitchSection(&FnStart->getSection());
// Clean exception handling frame information
Reset();
}
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());
AddValueSymbols(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 == 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
EmitBytes(StringRef(reinterpret_cast<const char *>(Opcodes.data()),
Opcodes.size()));
// 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)
EmitIntValue(0, 4);
}
void ARMELFStreamer::emitHandlerData() { FlushUnwindOpcodes(false); }
void ARMELFStreamer::emitPersonality(const MCSymbol *Per) {
Personality = Per;
UnwindOpAsm.setPersonality(Per);
}
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::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);
}
namespace llvm {
MCStreamer *createMCAsmStreamer(MCContext &Ctx, formatted_raw_ostream &OS,
bool isVerboseAsm, bool useLoc, bool useCFI,
bool useDwarfDirectory,
MCInstPrinter *InstPrint, MCCodeEmitter *CE,
MCAsmBackend *TAB, bool ShowInst) {
ARMTargetAsmStreamer *S = new ARMTargetAsmStreamer(OS, *InstPrint);
return llvm::createAsmStreamer(Ctx, S, OS, isVerboseAsm, useLoc, useCFI,
useDwarfDirectory, InstPrint, CE, TAB,
ShowInst);
}
MCELFStreamer* createARMELFStreamer(MCContext &Context, MCAsmBackend &TAB,
raw_ostream &OS, MCCodeEmitter *Emitter,
bool RelaxAll, bool NoExecStack,
bool IsThumb) {
ARMTargetELFStreamer *TS = new ARMTargetELFStreamer();
ARMELFStreamer *S =
new ARMELFStreamer(Context, TS, TAB, OS, Emitter, IsThumb);
// 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);
if (NoExecStack)
S->getAssembler().setNoExecStack(true);
return S;
}
}
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