#define DEBUG_TYPE "assembler"
#include "llvm/MC/MCAssembler.h"
-#include "llvm/MC/MCExpr.h"
-#include "llvm/MC/MCSectionMachO.h"
-#include "llvm/MC/MCSymbol.h"
-#include "llvm/MC/MCValue.h"
-#include "llvm/ADT/DenseMap.h"
-#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/ADT/StringExtras.h"
-#include "llvm/ADT/StringMap.h"
#include "llvm/ADT/Twine.h"
+#include "llvm/MC/MCAsmBackend.h"
+#include "llvm/MC/MCAsmLayout.h"
+#include "llvm/MC/MCCodeEmitter.h"
+#include "llvm/MC/MCContext.h"
+#include "llvm/MC/MCDwarf.h"
+#include "llvm/MC/MCExpr.h"
+#include "llvm/MC/MCFixupKindInfo.h"
+#include "llvm/MC/MCObjectWriter.h"
+#include "llvm/MC/MCSection.h"
+#include "llvm/MC/MCSymbol.h"
+#include "llvm/MC/MCValue.h"
+#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorHandling.h"
-#include "llvm/Support/MachO.h"
+#include "llvm/Support/LEB128.h"
+#include "llvm/Support/TargetRegistry.h"
#include "llvm/Support/raw_ostream.h"
-#include "llvm/Support/Debug.h"
-
-// FIXME: Gross.
-#include "../Target/X86/X86FixupKinds.h"
-#include <vector>
using namespace llvm;
-class MachObjectWriter;
-
-STATISTIC(EmittedFragments, "Number of emitted assembler fragments");
+namespace {
+namespace stats {
+STATISTIC(EmittedFragments, "Number of emitted assembler fragments - total");
+STATISTIC(EmittedRelaxableFragments,
+ "Number of emitted assembler fragments - relaxable");
+STATISTIC(EmittedDataFragments,
+ "Number of emitted assembler fragments - data");
+STATISTIC(EmittedCompactEncodedInstFragments,
+ "Number of emitted assembler fragments - compact encoded inst");
+STATISTIC(EmittedAlignFragments,
+ "Number of emitted assembler fragments - align");
+STATISTIC(EmittedFillFragments,
+ "Number of emitted assembler fragments - fill");
+STATISTIC(EmittedOrgFragments,
+ "Number of emitted assembler fragments - org");
+STATISTIC(evaluateFixup, "Number of evaluated fixups");
+STATISTIC(FragmentLayouts, "Number of fragment layouts");
+STATISTIC(ObjectBytes, "Number of emitted object file bytes");
+STATISTIC(RelaxationSteps, "Number of assembler layout and relaxation steps");
+STATISTIC(RelaxedInstructions, "Number of relaxed instructions");
+}
+}
// FIXME FIXME FIXME: There are number of places in this file where we convert
// what is a 64-bit assembler value used for computation into a value in the
// object file, which may truncate it. We should detect that truncation where
// invalid and report errors back.
-static void WriteFileData(raw_ostream &OS, const MCSectionData &SD,
- MachObjectWriter &MOW);
-
-static uint64_t WriteNopData(uint64_t Count, MachObjectWriter &MOW);
-
-/// isVirtualSection - Check if this is a section which does not actually exist
-/// in the object file.
-static bool isVirtualSection(const MCSection &Section) {
- // FIXME: Lame.
- const MCSectionMachO &SMO = static_cast<const MCSectionMachO&>(Section);
- unsigned Type = SMO.getTypeAndAttributes() & MCSectionMachO::SECTION_TYPE;
- return (Type == MCSectionMachO::S_ZEROFILL);
-}
+/* *** */
-static unsigned getFixupKindLog2Size(unsigned Kind) {
- switch (Kind) {
- default: llvm_unreachable("invalid fixup kind!");
- case X86::reloc_pcrel_1byte:
- case FK_Data_1: return 0;
- case FK_Data_2: return 1;
- case X86::reloc_pcrel_4byte:
- case X86::reloc_riprel_4byte:
- case FK_Data_4: return 2;
- case FK_Data_8: return 3;
- }
+MCAsmLayout::MCAsmLayout(MCAssembler &Asm)
+ : Assembler(Asm), LastValidFragment()
+ {
+ // Compute the section layout order. Virtual sections must go last.
+ for (MCAssembler::iterator it = Asm.begin(), ie = Asm.end(); it != ie; ++it)
+ if (!it->getSection().isVirtualSection())
+ SectionOrder.push_back(&*it);
+ for (MCAssembler::iterator it = Asm.begin(), ie = Asm.end(); it != ie; ++it)
+ if (it->getSection().isVirtualSection())
+ SectionOrder.push_back(&*it);
}
-static bool isFixupKindPCRel(unsigned Kind) {
- switch (Kind) {
- default:
+bool MCAsmLayout::isFragmentValid(const MCFragment *F) const {
+ const MCSectionData &SD = *F->getParent();
+ const MCFragment *LastValid = LastValidFragment.lookup(&SD);
+ if (!LastValid)
return false;
- case X86::reloc_pcrel_1byte:
- case X86::reloc_pcrel_4byte:
- case X86::reloc_riprel_4byte:
- return true;
- }
+ assert(LastValid->getParent() == F->getParent());
+ return F->getLayoutOrder() <= LastValid->getLayoutOrder();
}
-class MachObjectWriter {
- // See <mach-o/loader.h>.
- enum {
- Header_Magic32 = 0xFEEDFACE,
- Header_Magic64 = 0xFEEDFACF
- };
-
- static const unsigned Header32Size = 28;
- static const unsigned Header64Size = 32;
- static const unsigned SegmentLoadCommand32Size = 56;
- static const unsigned Section32Size = 68;
- static const unsigned SymtabLoadCommandSize = 24;
- static const unsigned DysymtabLoadCommandSize = 80;
- static const unsigned Nlist32Size = 12;
- static const unsigned RelocationInfoSize = 8;
-
- enum HeaderFileType {
- HFT_Object = 0x1
- };
-
- enum HeaderFlags {
- HF_SubsectionsViaSymbols = 0x2000
- };
-
- enum LoadCommandType {
- LCT_Segment = 0x1,
- LCT_Symtab = 0x2,
- LCT_Dysymtab = 0xb
- };
-
- // See <mach-o/nlist.h>.
- enum SymbolTypeType {
- STT_Undefined = 0x00,
- STT_Absolute = 0x02,
- STT_Section = 0x0e
- };
-
- enum SymbolTypeFlags {
- // If any of these bits are set, then the entry is a stab entry number (see
- // <mach-o/stab.h>. Otherwise the other masks apply.
- STF_StabsEntryMask = 0xe0,
-
- STF_TypeMask = 0x0e,
- STF_External = 0x01,
- STF_PrivateExtern = 0x10
- };
-
- /// IndirectSymbolFlags - Flags for encoding special values in the indirect
- /// symbol entry.
- enum IndirectSymbolFlags {
- ISF_Local = 0x80000000,
- ISF_Absolute = 0x40000000
- };
-
- /// RelocationFlags - Special flags for addresses.
- enum RelocationFlags {
- RF_Scattered = 0x80000000
- };
-
- enum RelocationInfoType {
- RIT_Vanilla = 0,
- RIT_Pair = 1,
- RIT_Difference = 2,
- RIT_PreboundLazyPointer = 3,
- RIT_LocalDifference = 4
- };
-
- /// MachSymbolData - Helper struct for containing some precomputed information
- /// on symbols.
- struct MachSymbolData {
- MCSymbolData *SymbolData;
- uint64_t StringIndex;
- uint8_t SectionIndex;
-
- // Support lexicographic sorting.
- bool operator<(const MachSymbolData &RHS) const {
- const std::string &Name = SymbolData->getSymbol().getName();
- return Name < RHS.SymbolData->getSymbol().getName();
- }
- };
-
- raw_ostream &OS;
- bool IsLSB;
-
-public:
- MachObjectWriter(raw_ostream &_OS, bool _IsLSB = true)
- : OS(_OS), IsLSB(_IsLSB) {
- }
-
- /// @name Helper Methods
- /// @{
-
- void Write8(uint8_t Value) {
- OS << char(Value);
- }
-
- void Write16(uint16_t Value) {
- if (IsLSB) {
- Write8(uint8_t(Value >> 0));
- Write8(uint8_t(Value >> 8));
- } else {
- Write8(uint8_t(Value >> 8));
- Write8(uint8_t(Value >> 0));
- }
- }
-
- void Write32(uint32_t Value) {
- if (IsLSB) {
- Write16(uint16_t(Value >> 0));
- Write16(uint16_t(Value >> 16));
- } else {
- Write16(uint16_t(Value >> 16));
- Write16(uint16_t(Value >> 0));
- }
- }
-
- void Write64(uint64_t Value) {
- if (IsLSB) {
- Write32(uint32_t(Value >> 0));
- Write32(uint32_t(Value >> 32));
- } else {
- Write32(uint32_t(Value >> 32));
- Write32(uint32_t(Value >> 0));
- }
- }
-
- void WriteZeros(unsigned N) {
- const char Zeros[16] = { 0 };
-
- for (unsigned i = 0, e = N / 16; i != e; ++i)
- OS << StringRef(Zeros, 16);
-
- OS << StringRef(Zeros, N % 16);
- }
-
- void WriteString(StringRef Str, unsigned ZeroFillSize = 0) {
- OS << Str;
- if (ZeroFillSize)
- WriteZeros(ZeroFillSize - Str.size());
- }
-
- /// @}
-
- void WriteHeader32(unsigned NumLoadCommands, unsigned LoadCommandsSize,
- bool SubsectionsViaSymbols) {
- uint32_t Flags = 0;
-
- if (SubsectionsViaSymbols)
- Flags |= HF_SubsectionsViaSymbols;
-
- // struct mach_header (28 bytes)
-
- uint64_t Start = OS.tell();
- (void) Start;
-
- Write32(Header_Magic32);
-
- // FIXME: Support cputype.
- Write32(MachO::CPUTypeI386);
- // FIXME: Support cpusubtype.
- Write32(MachO::CPUSubType_I386_ALL);
- Write32(HFT_Object);
- Write32(NumLoadCommands); // Object files have a single load command, the
- // segment.
- Write32(LoadCommandsSize);
- Write32(Flags);
-
- assert(OS.tell() - Start == Header32Size);
- }
-
- /// WriteSegmentLoadCommand32 - Write a 32-bit segment load command.
- ///
- /// \arg NumSections - The number of sections in this segment.
- /// \arg SectionDataSize - The total size of the sections.
- void WriteSegmentLoadCommand32(unsigned NumSections,
- uint64_t VMSize,
- uint64_t SectionDataStartOffset,
- uint64_t SectionDataSize) {
- // struct segment_command (56 bytes)
-
- uint64_t Start = OS.tell();
- (void) Start;
-
- Write32(LCT_Segment);
- Write32(SegmentLoadCommand32Size + NumSections * Section32Size);
-
- WriteString("", 16);
- Write32(0); // vmaddr
- Write32(VMSize); // vmsize
- Write32(SectionDataStartOffset); // file offset
- Write32(SectionDataSize); // file size
- Write32(0x7); // maxprot
- Write32(0x7); // initprot
- Write32(NumSections);
- Write32(0); // flags
-
- assert(OS.tell() - Start == SegmentLoadCommand32Size);
- }
-
- void WriteSection32(const MCSectionData &SD, uint64_t FileOffset,
- uint64_t RelocationsStart, unsigned NumRelocations) {
- // The offset is unused for virtual sections.
- if (isVirtualSection(SD.getSection())) {
- assert(SD.getFileSize() == 0 && "Invalid file size!");
- FileOffset = 0;
- }
-
- // struct section (68 bytes)
-
- uint64_t Start = OS.tell();
- (void) Start;
-
- // FIXME: cast<> support!
- const MCSectionMachO &Section =
- static_cast<const MCSectionMachO&>(SD.getSection());
- WriteString(Section.getSectionName(), 16);
- WriteString(Section.getSegmentName(), 16);
- Write32(SD.getAddress()); // address
- Write32(SD.getSize()); // size
- Write32(FileOffset);
-
- unsigned Flags = Section.getTypeAndAttributes();
- if (SD.hasInstructions())
- Flags |= MCSectionMachO::S_ATTR_SOME_INSTRUCTIONS;
-
- assert(isPowerOf2_32(SD.getAlignment()) && "Invalid alignment!");
- Write32(Log2_32(SD.getAlignment()));
- Write32(NumRelocations ? RelocationsStart : 0);
- Write32(NumRelocations);
- Write32(Flags);
- Write32(0); // reserved1
- Write32(Section.getStubSize()); // reserved2
-
- assert(OS.tell() - Start == Section32Size);
- }
-
- void WriteSymtabLoadCommand(uint32_t SymbolOffset, uint32_t NumSymbols,
- uint32_t StringTableOffset,
- uint32_t StringTableSize) {
- // struct symtab_command (24 bytes)
-
- uint64_t Start = OS.tell();
- (void) Start;
-
- Write32(LCT_Symtab);
- Write32(SymtabLoadCommandSize);
- Write32(SymbolOffset);
- Write32(NumSymbols);
- Write32(StringTableOffset);
- Write32(StringTableSize);
-
- assert(OS.tell() - Start == SymtabLoadCommandSize);
- }
-
- void WriteDysymtabLoadCommand(uint32_t FirstLocalSymbol,
- uint32_t NumLocalSymbols,
- uint32_t FirstExternalSymbol,
- uint32_t NumExternalSymbols,
- uint32_t FirstUndefinedSymbol,
- uint32_t NumUndefinedSymbols,
- uint32_t IndirectSymbolOffset,
- uint32_t NumIndirectSymbols) {
- // struct dysymtab_command (80 bytes)
-
- uint64_t Start = OS.tell();
- (void) Start;
-
- Write32(LCT_Dysymtab);
- Write32(DysymtabLoadCommandSize);
- Write32(FirstLocalSymbol);
- Write32(NumLocalSymbols);
- Write32(FirstExternalSymbol);
- Write32(NumExternalSymbols);
- Write32(FirstUndefinedSymbol);
- Write32(NumUndefinedSymbols);
- Write32(0); // tocoff
- Write32(0); // ntoc
- Write32(0); // modtaboff
- Write32(0); // nmodtab
- Write32(0); // extrefsymoff
- Write32(0); // nextrefsyms
- Write32(IndirectSymbolOffset);
- Write32(NumIndirectSymbols);
- Write32(0); // extreloff
- Write32(0); // nextrel
- Write32(0); // locreloff
- Write32(0); // nlocrel
-
- assert(OS.tell() - Start == DysymtabLoadCommandSize);
- }
-
- void WriteNlist32(MachSymbolData &MSD) {
- MCSymbolData &Data = *MSD.SymbolData;
- const MCSymbol &Symbol = Data.getSymbol();
- uint8_t Type = 0;
- uint16_t Flags = Data.getFlags();
- uint32_t Address = 0;
+void MCAsmLayout::invalidateFragmentsFrom(MCFragment *F) {
+ // If this fragment wasn't already valid, we don't need to do anything.
+ if (!isFragmentValid(F))
+ return;
- // Set the N_TYPE bits. See <mach-o/nlist.h>.
- //
- // FIXME: Are the prebound or indirect fields possible here?
- if (Symbol.isUndefined())
- Type = STT_Undefined;
- else if (Symbol.isAbsolute())
- Type = STT_Absolute;
- else
- Type = STT_Section;
-
- // FIXME: Set STAB bits.
-
- if (Data.isPrivateExtern())
- Type |= STF_PrivateExtern;
-
- // Set external bit.
- if (Data.isExternal() || Symbol.isUndefined())
- Type |= STF_External;
-
- // Compute the symbol address.
- if (Symbol.isDefined()) {
- if (Symbol.isAbsolute()) {
- llvm_unreachable("FIXME: Not yet implemented!");
- } else {
- Address = Data.getFragment()->getAddress() + Data.getOffset();
- }
- } else if (Data.isCommon()) {
- // Common symbols are encoded with the size in the address
- // field, and their alignment in the flags.
- Address = Data.getCommonSize();
-
- // Common alignment is packed into the 'desc' bits.
- if (unsigned Align = Data.getCommonAlignment()) {
- unsigned Log2Size = Log2_32(Align);
- assert((1U << Log2Size) == Align && "Invalid 'common' alignment!");
- if (Log2Size > 15)
- llvm_report_error("invalid 'common' alignment '" +
- Twine(Align) + "'");
- // FIXME: Keep this mask with the SymbolFlags enumeration.
- Flags = (Flags & 0xF0FF) | (Log2Size << 8);
- }
- }
+ // Otherwise, reset the last valid fragment to the previous fragment
+ // (if this is the first fragment, it will be NULL).
+ const MCSectionData &SD = *F->getParent();
+ LastValidFragment[&SD] = F->getPrevNode();
+}
- // struct nlist (12 bytes)
+void MCAsmLayout::ensureValid(const MCFragment *F) const {
+ MCSectionData &SD = *F->getParent();
- Write32(MSD.StringIndex);
- Write8(Type);
- Write8(MSD.SectionIndex);
+ MCFragment *Cur = LastValidFragment[&SD];
+ if (!Cur)
+ Cur = &*SD.begin();
+ else
+ Cur = Cur->getNextNode();
- // The Mach-O streamer uses the lowest 16-bits of the flags for the 'desc'
- // value.
- Write16(Flags);
- Write32(Address);
+ // Advance the layout position until the fragment is valid.
+ while (!isFragmentValid(F)) {
+ assert(Cur && "Layout bookkeeping error");
+ const_cast<MCAsmLayout*>(this)->layoutFragment(Cur);
+ Cur = Cur->getNextNode();
}
+}
- struct MachRelocationEntry {
- uint32_t Word0;
- uint32_t Word1;
- };
- void ComputeScatteredRelocationInfo(MCAssembler &Asm, MCFragment &Fragment,
- MCAsmFixup &Fixup,
- const MCValue &Target,
- DenseMap<const MCSymbol*,MCSymbolData*> &SymbolMap,
- std::vector<MachRelocationEntry> &Relocs) {
- uint32_t Address = Fragment.getOffset() + Fixup.Offset;
- unsigned IsPCRel = isFixupKindPCRel(Fixup.Kind);
- unsigned Log2Size = getFixupKindLog2Size(Fixup.Kind);
- unsigned Type = RIT_Vanilla;
-
- // See <reloc.h>.
- const MCSymbol *A = Target.getSymA();
- MCSymbolData *SD = SymbolMap.lookup(A);
-
- if (!SD->getFragment())
- llvm_report_error("symbol '" + A->getName() +
- "' can not be undefined in a subtraction expression");
-
- uint32_t Value = SD->getFragment()->getAddress() + SD->getOffset();
- uint32_t Value2 = 0;
-
- if (const MCSymbol *B = Target.getSymB()) {
- MCSymbolData *SD = SymbolMap.lookup(B);
-
- if (!SD->getFragment())
- llvm_report_error("symbol '" + B->getName() +
- "' can not be undefined in a subtraction expression");
-
- Type = RIT_LocalDifference;
- Value2 = SD->getFragment()->getAddress() + SD->getOffset();
- }
-
- // The value which goes in the fixup is current value of the expression.
- Fixup.FixedValue = Value - Value2 + Target.getConstant();
- if (IsPCRel)
- Fixup.FixedValue -= Address;
+uint64_t MCAsmLayout::getFragmentOffset(const MCFragment *F) const {
+ ensureValid(F);
+ assert(F->Offset != ~UINT64_C(0) && "Address not set!");
+ return F->Offset;
+}
- // If this fixup is a vanilla PC relative relocation for a local label, we
- // don't need a relocation.
- //
- // FIXME: Implement proper atom support.
- if (IsPCRel && Target.getSymA() && Target.getSymA()->isTemporary() &&
- !Target.getSymB())
- return;
-
- MachRelocationEntry MRE;
- MRE.Word0 = ((Address << 0) |
- (Type << 24) |
- (Log2Size << 28) |
- (IsPCRel << 30) |
- RF_Scattered);
- MRE.Word1 = Value;
- Relocs.push_back(MRE);
-
- if (Type == RIT_LocalDifference) {
- MachRelocationEntry MRE;
- MRE.Word0 = ((0 << 0) |
- (RIT_Pair << 24) |
- (Log2Size << 28) |
- (IsPCRel << 30) |
- RF_Scattered);
- MRE.Word1 = Value2;
- Relocs.push_back(MRE);
- }
- }
+uint64_t MCAsmLayout::getSymbolOffset(const MCSymbolData *SD) const {
+ const MCSymbol &S = SD->getSymbol();
- void ComputeRelocationInfo(MCAssembler &Asm, MCDataFragment &Fragment,
- MCAsmFixup &Fixup,
- DenseMap<const MCSymbol*,MCSymbolData*> &SymbolMap,
- std::vector<MachRelocationEntry> &Relocs) {
+ // If this is a variable, then recursively evaluate now.
+ if (S.isVariable()) {
MCValue Target;
- if (!Fixup.Value->EvaluateAsRelocatable(Target))
- llvm_report_error("expected relocatable expression");
-
- // If this is a difference or a local symbol plus an offset, then we need a
- // scattered relocation entry.
- if (Target.getSymB() ||
- (Target.getSymA() && !Target.getSymA()->isUndefined() &&
- Target.getConstant()))
- return ComputeScatteredRelocationInfo(Asm, Fragment, Fixup, Target,
- SymbolMap, Relocs);
-
- // See <reloc.h>.
- uint32_t Address = Fragment.getOffset() + Fixup.Offset;
- uint32_t Value = 0;
- unsigned Index = 0;
- unsigned IsPCRel = isFixupKindPCRel(Fixup.Kind);
- unsigned Log2Size = getFixupKindLog2Size(Fixup.Kind);
- unsigned IsExtern = 0;
- unsigned Type = 0;
-
- if (Target.isAbsolute()) { // constant
- // SymbolNum of 0 indicates the absolute section.
- //
- // FIXME: When is this generated?
- Type = RIT_Vanilla;
- Value = 0;
- llvm_unreachable("FIXME: Not yet implemented!");
- } else {
- const MCSymbol *Symbol = Target.getSymA();
- MCSymbolData *SD = SymbolMap.lookup(Symbol);
-
- if (Symbol->isUndefined()) {
- IsExtern = 1;
- Index = SD->getIndex();
- Value = 0;
- } else {
- // The index is the section ordinal.
- //
- // FIXME: O(N)
- Index = 1;
- MCAssembler::iterator it = Asm.begin(), ie = Asm.end();
- for (; it != ie; ++it, ++Index)
- if (&*it == SD->getFragment()->getParent())
- break;
- assert(it != ie && "Unable to find section index!");
- Value = SD->getFragment()->getAddress() + SD->getOffset();
- }
-
- Type = RIT_Vanilla;
- }
-
- // The value which goes in the fixup is current value of the expression.
- Fixup.FixedValue = Value + Target.getConstant();
- if (IsPCRel)
- Fixup.FixedValue -= Address;
-
- // If this fixup is a vanilla PC relative relocation for a local label, we
- // don't need a relocation.
- //
- // FIXME: Implement proper atom support.
- if (IsPCRel && Target.getSymA() && Target.getSymA()->isTemporary())
- return;
-
- // struct relocation_info (8 bytes)
- MachRelocationEntry MRE;
- MRE.Word0 = Address;
- MRE.Word1 = ((Index << 0) |
- (IsPCRel << 24) |
- (Log2Size << 25) |
- (IsExtern << 27) |
- (Type << 28));
- Relocs.push_back(MRE);
+ if (!S.getVariableValue()->EvaluateAsRelocatable(Target, *this))
+ report_fatal_error("unable to evaluate offset for variable '" +
+ S.getName() + "'");
+
+ // Verify that any used symbols are defined.
+ if (Target.getSymA() && Target.getSymA()->getSymbol().isUndefined())
+ report_fatal_error("unable to evaluate offset to undefined symbol '" +
+ Target.getSymA()->getSymbol().getName() + "'");
+ if (Target.getSymB() && Target.getSymB()->getSymbol().isUndefined())
+ report_fatal_error("unable to evaluate offset to undefined symbol '" +
+ Target.getSymB()->getSymbol().getName() + "'");
+
+ uint64_t Offset = Target.getConstant();
+ if (Target.getSymA())
+ Offset += getSymbolOffset(&Assembler.getSymbolData(
+ Target.getSymA()->getSymbol()));
+ if (Target.getSymB())
+ Offset -= getSymbolOffset(&Assembler.getSymbolData(
+ Target.getSymB()->getSymbol()));
+ return Offset;
}
- void BindIndirectSymbols(MCAssembler &Asm,
- DenseMap<const MCSymbol*,MCSymbolData*> &SymbolMap) {
- // This is the point where 'as' creates actual symbols for indirect symbols
- // (in the following two passes). It would be easier for us to do this
- // sooner when we see the attribute, but that makes getting the order in the
- // symbol table much more complicated than it is worth.
- //
- // FIXME: Revisit this when the dust settles.
-
- // Bind non lazy symbol pointers first.
- for (MCAssembler::indirect_symbol_iterator it = Asm.indirect_symbol_begin(),
- ie = Asm.indirect_symbol_end(); it != ie; ++it) {
- // FIXME: cast<> support!
- const MCSectionMachO &Section =
- static_cast<const MCSectionMachO&>(it->SectionData->getSection());
-
- unsigned Type =
- Section.getTypeAndAttributes() & MCSectionMachO::SECTION_TYPE;
- if (Type != MCSectionMachO::S_NON_LAZY_SYMBOL_POINTERS)
- continue;
-
- MCSymbolData *&Entry = SymbolMap[it->Symbol];
- if (!Entry)
- Entry = new MCSymbolData(*it->Symbol, 0, 0, &Asm);
- }
-
- // Then lazy symbol pointers and symbol stubs.
- for (MCAssembler::indirect_symbol_iterator it = Asm.indirect_symbol_begin(),
- ie = Asm.indirect_symbol_end(); it != ie; ++it) {
- // FIXME: cast<> support!
- const MCSectionMachO &Section =
- static_cast<const MCSectionMachO&>(it->SectionData->getSection());
-
- unsigned Type =
- Section.getTypeAndAttributes() & MCSectionMachO::SECTION_TYPE;
- if (Type != MCSectionMachO::S_LAZY_SYMBOL_POINTERS &&
- Type != MCSectionMachO::S_SYMBOL_STUBS)
- continue;
-
- MCSymbolData *&Entry = SymbolMap[it->Symbol];
- if (!Entry) {
- Entry = new MCSymbolData(*it->Symbol, 0, 0, &Asm);
-
- // Set the symbol type to undefined lazy, but only on construction.
- //
- // FIXME: Do not hardcode.
- Entry->setFlags(Entry->getFlags() | 0x0001);
- }
- }
- }
-
- /// ComputeSymbolTable - Compute the symbol table data
- ///
- /// \param StringTable [out] - The string table data.
- /// \param StringIndexMap [out] - Map from symbol names to offsets in the
- /// string table.
- void ComputeSymbolTable(MCAssembler &Asm, SmallString<256> &StringTable,
- std::vector<MachSymbolData> &LocalSymbolData,
- std::vector<MachSymbolData> &ExternalSymbolData,
- std::vector<MachSymbolData> &UndefinedSymbolData) {
- // Build section lookup table.
- DenseMap<const MCSection*, uint8_t> SectionIndexMap;
- unsigned Index = 1;
- for (MCAssembler::iterator it = Asm.begin(),
- ie = Asm.end(); it != ie; ++it, ++Index)
- SectionIndexMap[&it->getSection()] = Index;
- assert(Index <= 256 && "Too many sections!");
-
- // Index 0 is always the empty string.
- StringMap<uint64_t> StringIndexMap;
- StringTable += '\x00';
-
- // Build the symbol arrays and the string table, but only for non-local
- // symbols.
- //
- // The particular order that we collect the symbols and create the string
- // table, then sort the symbols is chosen to match 'as'. Even though it
- // doesn't matter for correctness, this is important for letting us diff .o
- // files.
- for (MCAssembler::symbol_iterator it = Asm.symbol_begin(),
- ie = Asm.symbol_end(); it != ie; ++it) {
- const MCSymbol &Symbol = it->getSymbol();
-
- // Ignore assembler temporaries.
- if (it->getSymbol().isTemporary())
- continue;
-
- if (!it->isExternal() && !Symbol.isUndefined())
- continue;
-
- uint64_t &Entry = StringIndexMap[Symbol.getName()];
- if (!Entry) {
- Entry = StringTable.size();
- StringTable += Symbol.getName();
- StringTable += '\x00';
- }
-
- MachSymbolData MSD;
- MSD.SymbolData = it;
- MSD.StringIndex = Entry;
-
- if (Symbol.isUndefined()) {
- MSD.SectionIndex = 0;
- UndefinedSymbolData.push_back(MSD);
- } else if (Symbol.isAbsolute()) {
- MSD.SectionIndex = 0;
- ExternalSymbolData.push_back(MSD);
- } else {
- MSD.SectionIndex = SectionIndexMap.lookup(&Symbol.getSection());
- assert(MSD.SectionIndex && "Invalid section index!");
- ExternalSymbolData.push_back(MSD);
- }
- }
-
- // Now add the data for local symbols.
- for (MCAssembler::symbol_iterator it = Asm.symbol_begin(),
- ie = Asm.symbol_end(); it != ie; ++it) {
- const MCSymbol &Symbol = it->getSymbol();
-
- // Ignore assembler temporaries.
- if (it->getSymbol().isTemporary())
- continue;
-
- if (it->isExternal() || Symbol.isUndefined())
- continue;
-
- uint64_t &Entry = StringIndexMap[Symbol.getName()];
- if (!Entry) {
- Entry = StringTable.size();
- StringTable += Symbol.getName();
- StringTable += '\x00';
- }
-
- MachSymbolData MSD;
- MSD.SymbolData = it;
- MSD.StringIndex = Entry;
-
- if (Symbol.isAbsolute()) {
- MSD.SectionIndex = 0;
- LocalSymbolData.push_back(MSD);
- } else {
- MSD.SectionIndex = SectionIndexMap.lookup(&Symbol.getSection());
- assert(MSD.SectionIndex && "Invalid section index!");
- LocalSymbolData.push_back(MSD);
- }
- }
-
- // External and undefined symbols are required to be in lexicographic order.
- std::sort(ExternalSymbolData.begin(), ExternalSymbolData.end());
- std::sort(UndefinedSymbolData.begin(), UndefinedSymbolData.end());
-
- // Set the symbol indices.
- Index = 0;
- for (unsigned i = 0, e = LocalSymbolData.size(); i != e; ++i)
- LocalSymbolData[i].SymbolData->setIndex(Index++);
- for (unsigned i = 0, e = ExternalSymbolData.size(); i != e; ++i)
- ExternalSymbolData[i].SymbolData->setIndex(Index++);
- for (unsigned i = 0, e = UndefinedSymbolData.size(); i != e; ++i)
- UndefinedSymbolData[i].SymbolData->setIndex(Index++);
-
- // The string table is padded to a multiple of 4.
- while (StringTable.size() % 4)
- StringTable += '\x00';
- }
+ assert(SD->getFragment() && "Invalid getOffset() on undefined symbol!");
+ return getFragmentOffset(SD->getFragment()) + SD->getOffset();
+}
- void WriteObject(MCAssembler &Asm) {
- unsigned NumSections = Asm.size();
+uint64_t MCAsmLayout::getSectionAddressSize(const MCSectionData *SD) const {
+ // The size is the last fragment's end offset.
+ const MCFragment &F = SD->getFragmentList().back();
+ return getFragmentOffset(&F) + getAssembler().computeFragmentSize(*this, F);
+}
- // Compute the symbol -> symbol data map.
- //
- // FIXME: This should not be here.
- DenseMap<const MCSymbol*, MCSymbolData *> SymbolMap;
- for (MCAssembler::symbol_iterator it = Asm.symbol_begin(),
- ie = Asm.symbol_end(); it != ie; ++it)
- SymbolMap[&it->getSymbol()] = it;
-
- // Create symbol data for any indirect symbols.
- BindIndirectSymbols(Asm, SymbolMap);
-
- // Compute symbol table information.
- SmallString<256> StringTable;
- std::vector<MachSymbolData> LocalSymbolData;
- std::vector<MachSymbolData> ExternalSymbolData;
- std::vector<MachSymbolData> UndefinedSymbolData;
- unsigned NumSymbols = Asm.symbol_size();
-
- // No symbol table command is written if there are no symbols.
- if (NumSymbols)
- ComputeSymbolTable(Asm, StringTable, LocalSymbolData, ExternalSymbolData,
- UndefinedSymbolData);
-
- // The section data starts after the header, the segment load command (and
- // section headers) and the symbol table.
- unsigned NumLoadCommands = 1;
- uint64_t LoadCommandsSize =
- SegmentLoadCommand32Size + NumSections * Section32Size;
-
- // Add the symbol table load command sizes, if used.
- if (NumSymbols) {
- NumLoadCommands += 2;
- LoadCommandsSize += SymtabLoadCommandSize + DysymtabLoadCommandSize;
- }
+uint64_t MCAsmLayout::getSectionFileSize(const MCSectionData *SD) const {
+ // Virtual sections have no file size.
+ if (SD->getSection().isVirtualSection())
+ return 0;
- // Compute the total size of the section data, as well as its file size and
- // vm size.
- uint64_t SectionDataStart = Header32Size + LoadCommandsSize;
- uint64_t SectionDataSize = 0;
- uint64_t SectionDataFileSize = 0;
- uint64_t VMSize = 0;
- for (MCAssembler::iterator it = Asm.begin(),
- ie = Asm.end(); it != ie; ++it) {
- MCSectionData &SD = *it;
-
- VMSize = std::max(VMSize, SD.getAddress() + SD.getSize());
-
- if (isVirtualSection(SD.getSection()))
- continue;
-
- SectionDataSize = std::max(SectionDataSize,
- SD.getAddress() + SD.getSize());
- SectionDataFileSize = std::max(SectionDataFileSize,
- SD.getAddress() + SD.getFileSize());
- }
+ // Otherwise, the file size is the same as the address space size.
+ return getSectionAddressSize(SD);
+}
- // The section data is padded to 4 bytes.
+uint64_t MCAsmLayout::computeBundlePadding(const MCFragment *F,
+ uint64_t FOffset, uint64_t FSize) {
+ uint64_t BundleSize = Assembler.getBundleAlignSize();
+ assert(BundleSize > 0 &&
+ "computeBundlePadding should only be called if bundling is enabled");
+ uint64_t BundleMask = BundleSize - 1;
+ uint64_t OffsetInBundle = FOffset & BundleMask;
+ uint64_t EndOfFragment = OffsetInBundle + FSize;
+
+ // There are two kinds of bundling restrictions:
+ //
+ // 1) For alignToBundleEnd(), add padding to ensure that the fragment will
+ // *end* on a bundle boundary.
+ // 2) Otherwise, check if the fragment would cross a bundle boundary. If it
+ // would, add padding until the end of the bundle so that the fragment
+ // will start in a new one.
+ if (F->alignToBundleEnd()) {
+ // Three possibilities here:
//
- // FIXME: Is this machine dependent?
- unsigned SectionDataPadding = OffsetToAlignment(SectionDataFileSize, 4);
- SectionDataFileSize += SectionDataPadding;
-
- // Write the prolog, starting with the header and load command...
- WriteHeader32(NumLoadCommands, LoadCommandsSize,
- Asm.getSubsectionsViaSymbols());
- WriteSegmentLoadCommand32(NumSections, VMSize,
- SectionDataStart, SectionDataSize);
-
- // ... and then the section headers.
+ // A) The fragment just happens to end at a bundle boundary, so we're good.
+ // B) The fragment ends before the current bundle boundary: pad it just
+ // enough to reach the boundary.
+ // C) The fragment ends after the current bundle boundary: pad it until it
+ // reaches the end of the next bundle boundary.
//
- // We also compute the section relocations while we do this. Note that
- // computing relocation info will also update the fixup to have the correct
- // value; this will overwrite the appropriate data in the fragment when it
- // is written.
- std::vector<MachRelocationEntry> RelocInfos;
- uint64_t RelocTableEnd = SectionDataStart + SectionDataFileSize;
- for (MCAssembler::iterator it = Asm.begin(),
- ie = Asm.end(); it != ie; ++it) {
- MCSectionData &SD = *it;
-
- // The assembler writes relocations in the reverse order they were seen.
- //
- // FIXME: It is probably more complicated than this.
- unsigned NumRelocsStart = RelocInfos.size();
- for (MCSectionData::reverse_iterator it2 = SD.rbegin(),
- ie2 = SD.rend(); it2 != ie2; ++it2)
- if (MCDataFragment *DF = dyn_cast<MCDataFragment>(&*it2))
- for (unsigned i = 0, e = DF->fixup_size(); i != e; ++i)
- ComputeRelocationInfo(Asm, *DF, DF->getFixups()[e - i - 1],
- SymbolMap, RelocInfos);
-
- unsigned NumRelocs = RelocInfos.size() - NumRelocsStart;
- uint64_t SectionStart = SectionDataStart + SD.getAddress();
- WriteSection32(SD, SectionStart, RelocTableEnd, NumRelocs);
- RelocTableEnd += NumRelocs * RelocationInfoSize;
- }
-
- // Write the symbol table load command, if used.
- if (NumSymbols) {
- unsigned FirstLocalSymbol = 0;
- unsigned NumLocalSymbols = LocalSymbolData.size();
- unsigned FirstExternalSymbol = FirstLocalSymbol + NumLocalSymbols;
- unsigned NumExternalSymbols = ExternalSymbolData.size();
- unsigned FirstUndefinedSymbol = FirstExternalSymbol + NumExternalSymbols;
- unsigned NumUndefinedSymbols = UndefinedSymbolData.size();
- unsigned NumIndirectSymbols = Asm.indirect_symbol_size();
- unsigned NumSymTabSymbols =
- NumLocalSymbols + NumExternalSymbols + NumUndefinedSymbols;
- uint64_t IndirectSymbolSize = NumIndirectSymbols * 4;
- uint64_t IndirectSymbolOffset = 0;
-
- // If used, the indirect symbols are written after the section data.
- if (NumIndirectSymbols)
- IndirectSymbolOffset = RelocTableEnd;
-
- // The symbol table is written after the indirect symbol data.
- uint64_t SymbolTableOffset = RelocTableEnd + IndirectSymbolSize;
-
- // The string table is written after symbol table.
- uint64_t StringTableOffset =
- SymbolTableOffset + NumSymTabSymbols * Nlist32Size;
- WriteSymtabLoadCommand(SymbolTableOffset, NumSymTabSymbols,
- StringTableOffset, StringTable.size());
-
- WriteDysymtabLoadCommand(FirstLocalSymbol, NumLocalSymbols,
- FirstExternalSymbol, NumExternalSymbols,
- FirstUndefinedSymbol, NumUndefinedSymbols,
- IndirectSymbolOffset, NumIndirectSymbols);
- }
-
- // Write the actual section data.
- for (MCAssembler::iterator it = Asm.begin(), ie = Asm.end(); it != ie; ++it)
- WriteFileData(OS, *it, *this);
-
- // Write the extra padding.
- WriteZeros(SectionDataPadding);
-
- // Write the relocation entries.
- for (unsigned i = 0, e = RelocInfos.size(); i != e; ++i) {
- Write32(RelocInfos[i].Word0);
- Write32(RelocInfos[i].Word1);
+ // Note: this code could be made shorter with some modulo trickery, but it's
+ // intentionally kept in its more explicit form for simplicity.
+ if (EndOfFragment == BundleSize)
+ return 0;
+ else if (EndOfFragment < BundleSize)
+ return BundleSize - EndOfFragment;
+ else { // EndOfFragment > BundleSize
+ return 2 * BundleSize - EndOfFragment;
}
-
- // Write the symbol table data, if used.
- if (NumSymbols) {
- // Write the indirect symbol entries.
- for (MCAssembler::indirect_symbol_iterator
- it = Asm.indirect_symbol_begin(),
- ie = Asm.indirect_symbol_end(); it != ie; ++it) {
- // Indirect symbols in the non lazy symbol pointer section have some
- // special handling.
- const MCSectionMachO &Section =
- static_cast<const MCSectionMachO&>(it->SectionData->getSection());
- unsigned Type =
- Section.getTypeAndAttributes() & MCSectionMachO::SECTION_TYPE;
- if (Type == MCSectionMachO::S_NON_LAZY_SYMBOL_POINTERS) {
- // If this symbol is defined and internal, mark it as such.
- if (it->Symbol->isDefined() &&
- !SymbolMap.lookup(it->Symbol)->isExternal()) {
- uint32_t Flags = ISF_Local;
- if (it->Symbol->isAbsolute())
- Flags |= ISF_Absolute;
- Write32(Flags);
- continue;
- }
- }
-
- Write32(SymbolMap[it->Symbol]->getIndex());
- }
-
- // FIXME: Check that offsets match computed ones.
-
- // Write the symbol table entries.
- for (unsigned i = 0, e = LocalSymbolData.size(); i != e; ++i)
- WriteNlist32(LocalSymbolData[i]);
- for (unsigned i = 0, e = ExternalSymbolData.size(); i != e; ++i)
- WriteNlist32(ExternalSymbolData[i]);
- for (unsigned i = 0, e = UndefinedSymbolData.size(); i != e; ++i)
- WriteNlist32(UndefinedSymbolData[i]);
-
- // Write the string table.
- OS << StringTable.str();
- }
- }
-
- void ApplyFixup(const MCAsmFixup &Fixup, MCDataFragment &DF) {
- unsigned Size = 1 << getFixupKindLog2Size(Fixup.Kind);
-
- // FIXME: Endianness assumption.
- assert(Fixup.Offset + Size <= DF.getContents().size() &&
- "Invalid fixup offset!");
- for (unsigned i = 0; i != Size; ++i)
- DF.getContents()[Fixup.Offset + i] = uint8_t(Fixup.FixedValue >> (i * 8));
- }
-};
+ } else if (EndOfFragment > BundleSize)
+ return BundleSize - OffsetInBundle;
+ else
+ return 0;
+}
/* *** */
MCFragment::MCFragment() : Kind(FragmentType(~0)) {
}
+MCFragment::~MCFragment() {
+}
+
MCFragment::MCFragment(FragmentType _Kind, MCSectionData *_Parent)
- : Kind(_Kind),
- Parent(_Parent),
- FileSize(~UINT64_C(0))
+ : Kind(_Kind), Parent(_Parent), Atom(0), Offset(~UINT64_C(0))
{
if (Parent)
Parent->getFragmentList().push_back(this);
}
-MCFragment::~MCFragment() {
+/* *** */
+
+MCEncodedFragment::~MCEncodedFragment() {
}
-uint64_t MCFragment::getAddress() const {
- assert(getParent() && "Missing Section!");
- return getParent()->getAddress() + Offset;
+/* *** */
+
+MCEncodedFragmentWithFixups::~MCEncodedFragmentWithFixups() {
}
/* *** */
MCSectionData::MCSectionData(const MCSection &_Section, MCAssembler *A)
: Section(&_Section),
+ Ordinal(~UINT32_C(0)),
Alignment(1),
- Address(~UINT64_C(0)),
- Size(~UINT64_C(0)),
- FileSize(~UINT64_C(0)),
+ BundleLockState(NotBundleLocked), BundleGroupBeforeFirstInst(false),
HasInstructions(false)
{
if (A)
A->getSectionList().push_back(this);
}
+MCSectionData::iterator
+MCSectionData::getSubsectionInsertionPoint(unsigned Subsection) {
+ if (Subsection == 0 && SubsectionFragmentMap.empty())
+ return end();
+
+ SmallVectorImpl<std::pair<unsigned, MCFragment *> >::iterator MI =
+ std::lower_bound(SubsectionFragmentMap.begin(), SubsectionFragmentMap.end(),
+ std::make_pair(Subsection, (MCFragment *)0));
+ bool ExactMatch = false;
+ if (MI != SubsectionFragmentMap.end()) {
+ ExactMatch = MI->first == Subsection;
+ if (ExactMatch)
+ ++MI;
+ }
+ iterator IP;
+ if (MI == SubsectionFragmentMap.end())
+ IP = end();
+ else
+ IP = MI->second;
+ if (!ExactMatch && Subsection != 0) {
+ // The GNU as documentation claims that subsections have an alignment of 4,
+ // although this appears not to be the case.
+ MCFragment *F = new MCDataFragment();
+ SubsectionFragmentMap.insert(MI, std::make_pair(Subsection, F));
+ getFragmentList().insert(IP, F);
+ F->setParent(this);
+ }
+ return IP;
+}
+
/* *** */
MCSymbolData::MCSymbolData() : Symbol(0) {}
uint64_t _Offset, MCAssembler *A)
: Symbol(&_Symbol), Fragment(_Fragment), Offset(_Offset),
IsExternal(false), IsPrivateExtern(false),
- CommonSize(0), CommonAlign(0), Flags(0), Index(0)
+ CommonSize(0), SymbolSize(0), CommonAlign(0),
+ Flags(0), Index(0)
{
if (A)
A->getSymbolList().push_back(this);
/* *** */
-MCAssembler::MCAssembler(MCContext &_Context, raw_ostream &_OS)
- : Context(_Context), OS(_OS), SubsectionsViaSymbols(false)
-{
+MCAssembler::MCAssembler(MCContext &Context_, MCAsmBackend &Backend_,
+ MCCodeEmitter &Emitter_, MCObjectWriter &Writer_,
+ raw_ostream &OS_)
+ : Context(Context_), Backend(Backend_), Emitter(Emitter_), Writer(Writer_),
+ OS(OS_), BundleAlignSize(0), RelaxAll(false), NoExecStack(false),
+ SubsectionsViaSymbols(false), ELFHeaderEFlags(0) {
}
MCAssembler::~MCAssembler() {
}
-void MCAssembler::LayoutSection(MCSectionData &SD) {
- uint64_t Address = SD.getAddress();
+void MCAssembler::reset() {
+ Sections.clear();
+ Symbols.clear();
+ SectionMap.clear();
+ SymbolMap.clear();
+ IndirectSymbols.clear();
+ DataRegions.clear();
+ ThumbFuncs.clear();
+ RelaxAll = false;
+ NoExecStack = false;
+ SubsectionsViaSymbols = false;
+ ELFHeaderEFlags = 0;
+
+ // reset objects owned by us
+ getBackend().reset();
+ getEmitter().reset();
+ getWriter().reset();
+}
+
+bool MCAssembler::isSymbolLinkerVisible(const MCSymbol &Symbol) const {
+ // Non-temporary labels should always be visible to the linker.
+ if (!Symbol.isTemporary())
+ return true;
- for (MCSectionData::iterator it = SD.begin(), ie = SD.end(); it != ie; ++it) {
- MCFragment &F = *it;
+ // Absolute temporary labels are never visible.
+ if (!Symbol.isInSection())
+ return false;
- F.setOffset(Address - SD.getAddress());
+ // Otherwise, check if the section requires symbols even for temporary labels.
+ return getBackend().doesSectionRequireSymbols(Symbol.getSection());
+}
- // Evaluate fragment size.
- switch (F.getKind()) {
- case MCFragment::FT_Align: {
- MCAlignFragment &AF = cast<MCAlignFragment>(F);
+const MCSymbolData *MCAssembler::getAtom(const MCSymbolData *SD) const {
+ // Linker visible symbols define atoms.
+ if (isSymbolLinkerVisible(SD->getSymbol()))
+ return SD;
- uint64_t Size = OffsetToAlignment(Address, AF.getAlignment());
- if (Size > AF.getMaxBytesToEmit())
- AF.setFileSize(0);
- else
- AF.setFileSize(Size);
- break;
- }
+ // Absolute and undefined symbols have no defining atom.
+ if (!SD->getFragment())
+ return 0;
- case MCFragment::FT_Data:
- case MCFragment::FT_Fill:
- F.setFileSize(F.getMaxFileSize());
- break;
+ // Non-linker visible symbols in sections which can't be atomized have no
+ // defining atom.
+ if (!getBackend().isSectionAtomizable(
+ SD->getFragment()->getParent()->getSection()))
+ return 0;
- case MCFragment::FT_Org: {
- MCOrgFragment &OF = cast<MCOrgFragment>(F);
+ // Otherwise, return the atom for the containing fragment.
+ return SD->getFragment()->getAtom();
+}
- MCValue Target;
- if (!OF.getOffset().EvaluateAsRelocatable(Target))
- llvm_report_error("expected relocatable expression");
+bool MCAssembler::evaluateFixup(const MCAsmLayout &Layout,
+ const MCFixup &Fixup, const MCFragment *DF,
+ MCValue &Target, uint64_t &Value) const {
+ ++stats::evaluateFixup;
- if (!Target.isAbsolute())
- llvm_unreachable("FIXME: Not yet implemented!");
- uint64_t OrgOffset = Target.getConstant();
- uint64_t Offset = Address - SD.getAddress();
+ if (!Fixup.getValue()->EvaluateAsRelocatable(Target, Layout))
+ getContext().FatalError(Fixup.getLoc(), "expected relocatable expression");
- // FIXME: We need a way to communicate this error.
- if (OrgOffset < Offset)
- llvm_report_error("invalid .org offset '" + Twine(OrgOffset) +
- "' (at offset '" + Twine(Offset) + "'");
+ bool IsPCRel = Backend.getFixupKindInfo(
+ Fixup.getKind()).Flags & MCFixupKindInfo::FKF_IsPCRel;
- F.setFileSize(OrgOffset - Offset);
- break;
+ bool IsResolved;
+ if (IsPCRel) {
+ if (Target.getSymB()) {
+ IsResolved = false;
+ } else if (!Target.getSymA()) {
+ IsResolved = false;
+ } else {
+ const MCSymbolRefExpr *A = Target.getSymA();
+ const MCSymbol &SA = A->getSymbol();
+ if (A->getKind() != MCSymbolRefExpr::VK_None ||
+ SA.AliasedSymbol().isUndefined()) {
+ IsResolved = false;
+ } else {
+ const MCSymbolData &DataA = getSymbolData(SA);
+ IsResolved =
+ getWriter().IsSymbolRefDifferenceFullyResolvedImpl(*this, DataA,
+ *DF, false, true);
+ }
}
+ } else {
+ IsResolved = Target.isAbsolute();
+ }
+
+ Value = Target.getConstant();
- case MCFragment::FT_ZeroFill: {
- MCZeroFillFragment &ZFF = cast<MCZeroFillFragment>(F);
+ if (const MCSymbolRefExpr *A = Target.getSymA()) {
+ const MCSymbol &Sym = A->getSymbol().AliasedSymbol();
+ if (Sym.isDefined())
+ Value += Layout.getSymbolOffset(&getSymbolData(Sym));
+ }
+ if (const MCSymbolRefExpr *B = Target.getSymB()) {
+ const MCSymbol &Sym = B->getSymbol().AliasedSymbol();
+ if (Sym.isDefined())
+ Value -= Layout.getSymbolOffset(&getSymbolData(Sym));
+ }
- // Align the fragment offset; it is safe to adjust the offset freely since
- // this is only in virtual sections.
- Address = RoundUpToAlignment(Address, ZFF.getAlignment());
- F.setOffset(Address - SD.getAddress());
- // FIXME: This is misnamed.
- F.setFileSize(ZFF.getSize());
- break;
- }
+ bool ShouldAlignPC = Backend.getFixupKindInfo(Fixup.getKind()).Flags &
+ MCFixupKindInfo::FKF_IsAlignedDownTo32Bits;
+ assert((ShouldAlignPC ? IsPCRel : true) &&
+ "FKF_IsAlignedDownTo32Bits is only allowed on PC-relative fixups!");
+
+ if (IsPCRel) {
+ uint32_t Offset = Layout.getFragmentOffset(DF) + Fixup.getOffset();
+
+ // A number of ARM fixups in Thumb mode require that the effective PC
+ // address be determined as the 32-bit aligned version of the actual offset.
+ if (ShouldAlignPC) Offset &= ~0x3;
+ Value -= Offset;
+ }
+
+ // Let the backend adjust the fixup value if necessary, including whether
+ // we need a relocation.
+ Backend.processFixupValue(*this, Layout, Fixup, DF, Target, Value,
+ IsResolved);
+
+ return IsResolved;
+}
+
+uint64_t MCAssembler::computeFragmentSize(const MCAsmLayout &Layout,
+ const MCFragment &F) const {
+ switch (F.getKind()) {
+ case MCFragment::FT_Data:
+ case MCFragment::FT_Relaxable:
+ case MCFragment::FT_CompactEncodedInst:
+ return cast<MCEncodedFragment>(F).getContents().size();
+ case MCFragment::FT_Fill:
+ return cast<MCFillFragment>(F).getSize();
+
+ case MCFragment::FT_LEB:
+ return cast<MCLEBFragment>(F).getContents().size();
+
+ case MCFragment::FT_Align: {
+ const MCAlignFragment &AF = cast<MCAlignFragment>(F);
+ unsigned Offset = Layout.getFragmentOffset(&AF);
+ unsigned Size = OffsetToAlignment(Offset, AF.getAlignment());
+ // If we are padding with nops, force the padding to be larger than the
+ // minimum nop size.
+ if (Size > 0 && AF.hasEmitNops()) {
+ while (Size % getBackend().getMinimumNopSize())
+ Size += AF.getAlignment();
}
+ if (Size > AF.getMaxBytesToEmit())
+ return 0;
+ return Size;
+ }
- Address += F.getFileSize();
+ case MCFragment::FT_Org: {
+ const MCOrgFragment &OF = cast<MCOrgFragment>(F);
+ int64_t TargetLocation;
+ if (!OF.getOffset().EvaluateAsAbsolute(TargetLocation, Layout))
+ report_fatal_error("expected assembly-time absolute expression");
+
+ // FIXME: We need a way to communicate this error.
+ uint64_t FragmentOffset = Layout.getFragmentOffset(&OF);
+ int64_t Size = TargetLocation - FragmentOffset;
+ if (Size < 0 || Size >= 0x40000000)
+ report_fatal_error("invalid .org offset '" + Twine(TargetLocation) +
+ "' (at offset '" + Twine(FragmentOffset) + "')");
+ return Size;
}
- // Set the section sizes.
- SD.setSize(Address - SD.getAddress());
- if (isVirtualSection(SD.getSection()))
- SD.setFileSize(0);
- else
- SD.setFileSize(Address - SD.getAddress());
+ case MCFragment::FT_Dwarf:
+ return cast<MCDwarfLineAddrFragment>(F).getContents().size();
+ case MCFragment::FT_DwarfFrame:
+ return cast<MCDwarfCallFrameFragment>(F).getContents().size();
+ }
+
+ llvm_unreachable("invalid fragment kind");
}
-/// WriteNopData - Write optimal nops to the output file for the \arg Count
-/// bytes. This returns the number of bytes written. It may return 0 if
-/// the \arg Count is more than the maximum optimal nops.
-///
-/// FIXME this is X86 32-bit specific and should move to a better place.
-static uint64_t WriteNopData(uint64_t Count, MachObjectWriter &MOW) {
- static const uint8_t Nops[16][16] = {
- // nop
- {0x90},
- // xchg %ax,%ax
- {0x66, 0x90},
- // nopl (%[re]ax)
- {0x0f, 0x1f, 0x00},
- // nopl 0(%[re]ax)
- {0x0f, 0x1f, 0x40, 0x00},
- // nopl 0(%[re]ax,%[re]ax,1)
- {0x0f, 0x1f, 0x44, 0x00, 0x00},
- // nopw 0(%[re]ax,%[re]ax,1)
- {0x66, 0x0f, 0x1f, 0x44, 0x00, 0x00},
- // nopl 0L(%[re]ax)
- {0x0f, 0x1f, 0x80, 0x00, 0x00, 0x00, 0x00},
- // nopl 0L(%[re]ax,%[re]ax,1)
- {0x0f, 0x1f, 0x84, 0x00, 0x00, 0x00, 0x00, 0x00},
- // nopw 0L(%[re]ax,%[re]ax,1)
- {0x66, 0x0f, 0x1f, 0x84, 0x00, 0x00, 0x00, 0x00, 0x00},
- // nopw %cs:0L(%[re]ax,%[re]ax,1)
- {0x66, 0x2e, 0x0f, 0x1f, 0x84, 0x00, 0x00, 0x00, 0x00, 0x00},
- // nopl 0(%[re]ax,%[re]ax,1)
- // nopw 0(%[re]ax,%[re]ax,1)
- {0x0f, 0x1f, 0x44, 0x00, 0x00,
- 0x66, 0x0f, 0x1f, 0x44, 0x00, 0x00},
- // nopw 0(%[re]ax,%[re]ax,1)
- // nopw 0(%[re]ax,%[re]ax,1)
- {0x66, 0x0f, 0x1f, 0x44, 0x00, 0x00,
- 0x66, 0x0f, 0x1f, 0x44, 0x00, 0x00},
- // nopw 0(%[re]ax,%[re]ax,1)
- // nopl 0L(%[re]ax) */
- {0x66, 0x0f, 0x1f, 0x44, 0x00, 0x00,
- 0x0f, 0x1f, 0x80, 0x00, 0x00, 0x00, 0x00},
- // nopl 0L(%[re]ax)
- // nopl 0L(%[re]ax)
- {0x0f, 0x1f, 0x80, 0x00, 0x00, 0x00, 0x00,
- 0x0f, 0x1f, 0x80, 0x00, 0x00, 0x00, 0x00},
- // nopl 0L(%[re]ax)
- // nopl 0L(%[re]ax,%[re]ax,1)
- {0x0f, 0x1f, 0x80, 0x00, 0x00, 0x00, 0x00,
- 0x0f, 0x1f, 0x84, 0x00, 0x00, 0x00, 0x00, 0x00}
- };
-
- if (Count > 15)
- return 0;
+void MCAsmLayout::layoutFragment(MCFragment *F) {
+ MCFragment *Prev = F->getPrevNode();
+
+ // We should never try to recompute something which is valid.
+ assert(!isFragmentValid(F) && "Attempt to recompute a valid fragment!");
+ // We should never try to compute the fragment layout if its predecessor
+ // isn't valid.
+ assert((!Prev || isFragmentValid(Prev)) &&
+ "Attempt to compute fragment before its predecessor!");
- for (uint64_t i = 0; i < Count; i++)
- MOW.Write8 (uint8_t(Nops[Count - 1][i]));
+ ++stats::FragmentLayouts;
- return Count;
+ // Compute fragment offset and size.
+ if (Prev)
+ F->Offset = Prev->Offset + getAssembler().computeFragmentSize(*this, *Prev);
+ else
+ F->Offset = 0;
+ LastValidFragment[F->getParent()] = F;
+
+ // If bundling is enabled and this fragment has instructions in it, it has to
+ // obey the bundling restrictions. With padding, we'll have:
+ //
+ //
+ // BundlePadding
+ // |||
+ // -------------------------------------
+ // Prev |##########| F |
+ // -------------------------------------
+ // ^
+ // |
+ // F->Offset
+ //
+ // The fragment's offset will point to after the padding, and its computed
+ // size won't include the padding.
+ //
+ if (Assembler.isBundlingEnabled() && F->hasInstructions()) {
+ assert(isa<MCEncodedFragment>(F) &&
+ "Only MCEncodedFragment implementations have instructions");
+ uint64_t FSize = Assembler.computeFragmentSize(*this, *F);
+
+ if (FSize > Assembler.getBundleAlignSize())
+ report_fatal_error("Fragment can't be larger than a bundle size");
+
+ uint64_t RequiredBundlePadding = computeBundlePadding(F, F->Offset, FSize);
+ if (RequiredBundlePadding > UINT8_MAX)
+ report_fatal_error("Padding cannot exceed 255 bytes");
+ F->setBundlePadding(static_cast<uint8_t>(RequiredBundlePadding));
+ F->Offset += RequiredBundlePadding;
+ }
}
-/// WriteFileData - Write the \arg F data to the output file.
-static void WriteFileData(raw_ostream &OS, const MCFragment &F,
- MachObjectWriter &MOW) {
- uint64_t Start = OS.tell();
- (void) Start;
+/// \brief Write the contents of a fragment to the given object writer. Expects
+/// a MCEncodedFragment.
+static void writeFragmentContents(const MCFragment &F, MCObjectWriter *OW) {
+ const MCEncodedFragment &EF = cast<MCEncodedFragment>(F);
+ OW->WriteBytes(EF.getContents());
+}
- ++EmittedFragments;
+/// \brief Write the fragment \p F to the output file.
+static void writeFragment(const MCAssembler &Asm, const MCAsmLayout &Layout,
+ const MCFragment &F) {
+ MCObjectWriter *OW = &Asm.getWriter();
// FIXME: Embed in fragments instead?
+ uint64_t FragmentSize = Asm.computeFragmentSize(Layout, F);
+
+ // Should NOP padding be written out before this fragment?
+ unsigned BundlePadding = F.getBundlePadding();
+ if (BundlePadding > 0) {
+ assert(Asm.isBundlingEnabled() &&
+ "Writing bundle padding with disabled bundling");
+ assert(F.hasInstructions() &&
+ "Writing bundle padding for a fragment without instructions");
+
+ unsigned TotalLength = BundlePadding + static_cast<unsigned>(FragmentSize);
+ if (F.alignToBundleEnd() && TotalLength > Asm.getBundleAlignSize()) {
+ // If the padding itself crosses a bundle boundary, it must be emitted
+ // in 2 pieces, since even nop instructions must not cross boundaries.
+ // v--------------v <- BundleAlignSize
+ // v---------v <- BundlePadding
+ // ----------------------------
+ // | Prev |####|####| F |
+ // ----------------------------
+ // ^-------------------^ <- TotalLength
+ unsigned DistanceToBoundary = TotalLength - Asm.getBundleAlignSize();
+ if (!Asm.getBackend().writeNopData(DistanceToBoundary, OW))
+ report_fatal_error("unable to write NOP sequence of " +
+ Twine(DistanceToBoundary) + " bytes");
+ BundlePadding -= DistanceToBoundary;
+ }
+ if (!Asm.getBackend().writeNopData(BundlePadding, OW))
+ report_fatal_error("unable to write NOP sequence of " +
+ Twine(BundlePadding) + " bytes");
+ }
+
+ // This variable (and its dummy usage) is to participate in the assert at
+ // the end of the function.
+ uint64_t Start = OW->getStream().tell();
+ (void) Start;
+
+ ++stats::EmittedFragments;
+
switch (F.getKind()) {
case MCFragment::FT_Align: {
- MCAlignFragment &AF = cast<MCAlignFragment>(F);
- uint64_t Count = AF.getFileSize() / AF.getValueSize();
+ ++stats::EmittedAlignFragments;
+ const MCAlignFragment &AF = cast<MCAlignFragment>(F);
+ assert(AF.getValueSize() && "Invalid virtual align in concrete fragment!");
+
+ uint64_t Count = FragmentSize / AF.getValueSize();
// FIXME: This error shouldn't actually occur (the front end should emit
// multiple .align directives to enforce the semantics it wants), but is
// severe enough that we want to report it. How to handle this?
- if (Count * AF.getValueSize() != AF.getFileSize())
- llvm_report_error("undefined .align directive, value size '" +
+ if (Count * AF.getValueSize() != FragmentSize)
+ report_fatal_error("undefined .align directive, value size '" +
Twine(AF.getValueSize()) +
"' is not a divisor of padding size '" +
- Twine(AF.getFileSize()) + "'");
+ Twine(FragmentSize) + "'");
// See if we are aligning with nops, and if so do that first to try to fill
// the Count bytes. Then if that did not fill any bytes or there are any
- // bytes left to fill use the the Value and ValueSize to fill the rest.
- if (AF.getEmitNops()) {
- uint64_t NopByteCount = WriteNopData(Count, MOW);
- Count -= NopByteCount;
+ // bytes left to fill use the Value and ValueSize to fill the rest.
+ // If we are aligning with nops, ask that target to emit the right data.
+ if (AF.hasEmitNops()) {
+ if (!Asm.getBackend().writeNopData(Count, OW))
+ report_fatal_error("unable to write nop sequence of " +
+ Twine(Count) + " bytes");
+ break;
}
+ // Otherwise, write out in multiples of the value size.
for (uint64_t i = 0; i != Count; ++i) {
switch (AF.getValueSize()) {
- default:
- assert(0 && "Invalid size!");
- case 1: MOW.Write8 (uint8_t (AF.getValue())); break;
- case 2: MOW.Write16(uint16_t(AF.getValue())); break;
- case 4: MOW.Write32(uint32_t(AF.getValue())); break;
- case 8: MOW.Write64(uint64_t(AF.getValue())); break;
+ default: llvm_unreachable("Invalid size!");
+ case 1: OW->Write8 (uint8_t (AF.getValue())); break;
+ case 2: OW->Write16(uint16_t(AF.getValue())); break;
+ case 4: OW->Write32(uint32_t(AF.getValue())); break;
+ case 8: OW->Write64(uint64_t(AF.getValue())); break;
}
}
break;
}
- case MCFragment::FT_Data: {
- MCDataFragment &DF = cast<MCDataFragment>(F);
+ case MCFragment::FT_Data:
+ ++stats::EmittedDataFragments;
+ writeFragmentContents(F, OW);
+ break;
- // Apply the fixups.
- //
- // FIXME: Move elsewhere.
- for (MCDataFragment::const_fixup_iterator it = DF.fixup_begin(),
- ie = DF.fixup_end(); it != ie; ++it)
- MOW.ApplyFixup(*it, DF);
+ case MCFragment::FT_Relaxable:
+ ++stats::EmittedRelaxableFragments;
+ writeFragmentContents(F, OW);
+ break;
- OS << cast<MCDataFragment>(F).getContents().str();
+ case MCFragment::FT_CompactEncodedInst:
+ ++stats::EmittedCompactEncodedInstFragments;
+ writeFragmentContents(F, OW);
break;
- }
case MCFragment::FT_Fill: {
- MCFillFragment &FF = cast<MCFillFragment>(F);
- for (uint64_t i = 0, e = FF.getCount(); i != e; ++i) {
+ ++stats::EmittedFillFragments;
+ const MCFillFragment &FF = cast<MCFillFragment>(F);
+
+ assert(FF.getValueSize() && "Invalid virtual align in concrete fragment!");
+
+ for (uint64_t i = 0, e = FF.getSize() / FF.getValueSize(); i != e; ++i) {
switch (FF.getValueSize()) {
- default:
- assert(0 && "Invalid size!");
- case 1: MOW.Write8 (uint8_t (FF.getValue())); break;
- case 2: MOW.Write16(uint16_t(FF.getValue())); break;
- case 4: MOW.Write32(uint32_t(FF.getValue())); break;
- case 8: MOW.Write64(uint64_t(FF.getValue())); break;
+ default: llvm_unreachable("Invalid size!");
+ case 1: OW->Write8 (uint8_t (FF.getValue())); break;
+ case 2: OW->Write16(uint16_t(FF.getValue())); break;
+ case 4: OW->Write32(uint32_t(FF.getValue())); break;
+ case 8: OW->Write64(uint64_t(FF.getValue())); break;
}
}
break;
}
+ case MCFragment::FT_LEB: {
+ const MCLEBFragment &LF = cast<MCLEBFragment>(F);
+ OW->WriteBytes(LF.getContents().str());
+ break;
+ }
+
case MCFragment::FT_Org: {
- MCOrgFragment &OF = cast<MCOrgFragment>(F);
+ ++stats::EmittedOrgFragments;
+ const MCOrgFragment &OF = cast<MCOrgFragment>(F);
- for (uint64_t i = 0, e = OF.getFileSize(); i != e; ++i)
- MOW.Write8(uint8_t(OF.getValue()));
+ for (uint64_t i = 0, e = FragmentSize; i != e; ++i)
+ OW->Write8(uint8_t(OF.getValue()));
break;
}
- case MCFragment::FT_ZeroFill: {
- assert(0 && "Invalid zero fill fragment in concrete section!");
+ case MCFragment::FT_Dwarf: {
+ const MCDwarfLineAddrFragment &OF = cast<MCDwarfLineAddrFragment>(F);
+ OW->WriteBytes(OF.getContents().str());
+ break;
+ }
+ case MCFragment::FT_DwarfFrame: {
+ const MCDwarfCallFrameFragment &CF = cast<MCDwarfCallFrameFragment>(F);
+ OW->WriteBytes(CF.getContents().str());
break;
}
}
- assert(OS.tell() - Start == F.getFileSize());
+ assert(OW->getStream().tell() - Start == FragmentSize &&
+ "The stream should advance by fragment size");
}
-/// WriteFileData - Write the \arg SD data to the output file.
-static void WriteFileData(raw_ostream &OS, const MCSectionData &SD,
- MachObjectWriter &MOW) {
+void MCAssembler::writeSectionData(const MCSectionData *SD,
+ const MCAsmLayout &Layout) const {
// Ignore virtual sections.
- if (isVirtualSection(SD.getSection())) {
- assert(SD.getFileSize() == 0);
+ if (SD->getSection().isVirtualSection()) {
+ assert(Layout.getSectionFileSize(SD) == 0 && "Invalid size for section!");
+
+ // Check that contents are only things legal inside a virtual section.
+ for (MCSectionData::const_iterator it = SD->begin(),
+ ie = SD->end(); it != ie; ++it) {
+ switch (it->getKind()) {
+ default: llvm_unreachable("Invalid fragment in virtual section!");
+ case MCFragment::FT_Data: {
+ // Check that we aren't trying to write a non-zero contents (or fixups)
+ // into a virtual section. This is to support clients which use standard
+ // directives to fill the contents of virtual sections.
+ const MCDataFragment &DF = cast<MCDataFragment>(*it);
+ assert(DF.fixup_begin() == DF.fixup_end() &&
+ "Cannot have fixups in virtual section!");
+ for (unsigned i = 0, e = DF.getContents().size(); i != e; ++i)
+ assert(DF.getContents()[i] == 0 &&
+ "Invalid data value for virtual section!");
+ break;
+ }
+ case MCFragment::FT_Align:
+ // Check that we aren't trying to write a non-zero value into a virtual
+ // section.
+ assert((cast<MCAlignFragment>(it)->getValueSize() == 0 ||
+ cast<MCAlignFragment>(it)->getValue() == 0) &&
+ "Invalid align in virtual section!");
+ break;
+ case MCFragment::FT_Fill:
+ assert((cast<MCFillFragment>(it)->getValueSize() == 0 ||
+ cast<MCFillFragment>(it)->getValue() == 0) &&
+ "Invalid fill in virtual section!");
+ break;
+ }
+ }
+
return;
}
- uint64_t Start = OS.tell();
- (void) Start;
+ uint64_t Start = getWriter().getStream().tell();
+ (void)Start;
- for (MCSectionData::const_iterator it = SD.begin(),
- ie = SD.end(); it != ie; ++it)
- WriteFileData(OS, *it, MOW);
+ for (MCSectionData::const_iterator it = SD->begin(), ie = SD->end();
+ it != ie; ++it)
+ writeFragment(*this, Layout, *it);
+
+ assert(getWriter().getStream().tell() - Start ==
+ Layout.getSectionAddressSize(SD));
+}
- // Add section padding.
- assert(SD.getFileSize() >= SD.getSize() && "Invalid section sizes!");
- MOW.WriteZeros(SD.getFileSize() - SD.getSize());
- assert(OS.tell() - Start == SD.getFileSize());
+uint64_t MCAssembler::handleFixup(const MCAsmLayout &Layout,
+ MCFragment &F,
+ const MCFixup &Fixup) {
+ // Evaluate the fixup.
+ MCValue Target;
+ uint64_t FixedValue;
+ if (!evaluateFixup(Layout, Fixup, &F, Target, FixedValue)) {
+ // The fixup was unresolved, we need a relocation. Inform the object
+ // writer of the relocation, and give it an opportunity to adjust the
+ // fixup value if need be.
+ getWriter().RecordRelocation(*this, Layout, &F, Fixup, Target, FixedValue);
+ }
+ return FixedValue;
}
void MCAssembler::Finish() {
llvm::errs() << "assembler backend - pre-layout\n--\n";
dump(); });
- // Layout the concrete sections and fragments.
- uint64_t Address = 0;
- MCSectionData *Prev = 0;
- for (iterator it = begin(), ie = end(); it != ie; ++it) {
- MCSectionData &SD = *it;
-
- // Skip virtual sections.
- if (isVirtualSection(SD.getSection()))
- continue;
-
- // Align this section if necessary by adding padding bytes to the previous
- // section.
- if (uint64_t Pad = OffsetToAlignment(Address, it->getAlignment())) {
- assert(Prev && "Missing prev section!");
- Prev->setFileSize(Prev->getFileSize() + Pad);
- Address += Pad;
- }
+ // Create the layout object.
+ MCAsmLayout Layout(*this);
- // Layout the section fragments and its size.
- SD.setAddress(Address);
- LayoutSection(SD);
- Address += SD.getFileSize();
+ // Create dummy fragments and assign section ordinals.
+ unsigned SectionIndex = 0;
+ for (MCAssembler::iterator it = begin(), ie = end(); it != ie; ++it) {
+ // Create dummy fragments to eliminate any empty sections, this simplifies
+ // layout.
+ if (it->getFragmentList().empty())
+ new MCDataFragment(it);
- Prev = &SD;
+ it->setOrdinal(SectionIndex++);
}
- // Layout the virtual sections.
- for (iterator it = begin(), ie = end(); it != ie; ++it) {
- MCSectionData &SD = *it;
+ // Assign layout order indices to sections and fragments.
+ for (unsigned i = 0, e = Layout.getSectionOrder().size(); i != e; ++i) {
+ MCSectionData *SD = Layout.getSectionOrder()[i];
+ SD->setLayoutOrder(i);
- if (!isVirtualSection(SD.getSection()))
- continue;
+ unsigned FragmentIndex = 0;
+ for (MCSectionData::iterator iFrag = SD->begin(), iFragEnd = SD->end();
+ iFrag != iFragEnd; ++iFrag)
+ iFrag->setLayoutOrder(FragmentIndex++);
+ }
- // Align this section if necessary by adding padding bytes to the previous
- // section.
- if (uint64_t Pad = OffsetToAlignment(Address, it->getAlignment()))
- Address += Pad;
+ // Layout until everything fits.
+ while (layoutOnce(Layout))
+ continue;
- SD.setAddress(Address);
- LayoutSection(SD);
- Address += SD.getSize();
+ DEBUG_WITH_TYPE("mc-dump", {
+ llvm::errs() << "assembler backend - post-relaxation\n--\n";
+ dump(); });
- }
+ // Finalize the layout, including fragment lowering.
+ finishLayout(Layout);
DEBUG_WITH_TYPE("mc-dump", {
- llvm::errs() << "assembler backend - post-layout\n--\n";
+ llvm::errs() << "assembler backend - final-layout\n--\n";
dump(); });
+ uint64_t StartOffset = OS.tell();
+
+ // Allow the object writer a chance to perform post-layout binding (for
+ // example, to set the index fields in the symbol data).
+ getWriter().ExecutePostLayoutBinding(*this, Layout);
+
+ // Evaluate and apply the fixups, generating relocation entries as necessary.
+ for (MCAssembler::iterator it = begin(), ie = end(); it != ie; ++it) {
+ for (MCSectionData::iterator it2 = it->begin(),
+ ie2 = it->end(); it2 != ie2; ++it2) {
+ MCEncodedFragmentWithFixups *F =
+ dyn_cast<MCEncodedFragmentWithFixups>(it2);
+ if (F) {
+ for (MCEncodedFragmentWithFixups::fixup_iterator it3 = F->fixup_begin(),
+ ie3 = F->fixup_end(); it3 != ie3; ++it3) {
+ MCFixup &Fixup = *it3;
+ uint64_t FixedValue = handleFixup(Layout, *F, Fixup);
+ getBackend().applyFixup(Fixup, F->getContents().data(),
+ F->getContents().size(), FixedValue);
+ }
+ }
+ }
+ }
+
// Write the object file.
- MachObjectWriter MOW(OS);
- MOW.WriteObject(*this);
+ getWriter().WriteObject(*this, Layout);
- OS.flush();
+ stats::ObjectBytes += OS.tell() - StartOffset;
}
+bool MCAssembler::fixupNeedsRelaxation(const MCFixup &Fixup,
+ const MCRelaxableFragment *DF,
+ const MCAsmLayout &Layout) const {
+ // If we cannot resolve the fixup value, it requires relaxation.
+ MCValue Target;
+ uint64_t Value;
+ if (!evaluateFixup(Layout, Fixup, DF, Target, Value))
+ return true;
-// Debugging methods
+ return getBackend().fixupNeedsRelaxation(Fixup, Value, DF, Layout);
+}
-namespace llvm {
+bool MCAssembler::fragmentNeedsRelaxation(const MCRelaxableFragment *F,
+ const MCAsmLayout &Layout) const {
+ // If this inst doesn't ever need relaxation, ignore it. This occurs when we
+ // are intentionally pushing out inst fragments, or because we relaxed a
+ // previous instruction to one that doesn't need relaxation.
+ if (!getBackend().mayNeedRelaxation(F->getInst()))
+ return false;
-raw_ostream &operator<<(raw_ostream &OS, const MCAsmFixup &AF) {
- OS << "<MCAsmFixup" << " Offset:" << AF.Offset << " Value:" << *AF.Value
- << " Kind:" << AF.Kind << ">";
- return OS;
-}
+ for (MCRelaxableFragment::const_fixup_iterator it = F->fixup_begin(),
+ ie = F->fixup_end(); it != ie; ++it)
+ if (fixupNeedsRelaxation(*it, F, Layout))
+ return true;
+ return false;
}
-void MCFragment::dump() {
- raw_ostream &OS = llvm::errs();
+bool MCAssembler::relaxInstruction(MCAsmLayout &Layout,
+ MCRelaxableFragment &F) {
+ if (!fragmentNeedsRelaxation(&F, Layout))
+ return false;
- OS << "<MCFragment " << (void*) this << " Offset:" << Offset
- << " FileSize:" << FileSize;
+ ++stats::RelaxedInstructions;
- OS << ">";
+ // FIXME-PERF: We could immediately lower out instructions if we can tell
+ // they are fully resolved, to avoid retesting on later passes.
+
+ // Relax the fragment.
+
+ MCInst Relaxed;
+ getBackend().relaxInstruction(F.getInst(), Relaxed);
+
+ // Encode the new instruction.
+ //
+ // FIXME-PERF: If it matters, we could let the target do this. It can
+ // probably do so more efficiently in many cases.
+ SmallVector<MCFixup, 4> Fixups;
+ SmallString<256> Code;
+ raw_svector_ostream VecOS(Code);
+ getEmitter().EncodeInstruction(Relaxed, VecOS, Fixups);
+ VecOS.flush();
+
+ // Update the fragment.
+ F.setInst(Relaxed);
+ F.getContents() = Code;
+ F.getFixups() = Fixups;
+
+ return true;
}
-void MCAlignFragment::dump() {
- raw_ostream &OS = llvm::errs();
+bool MCAssembler::relaxLEB(MCAsmLayout &Layout, MCLEBFragment &LF) {
+ int64_t Value = 0;
+ uint64_t OldSize = LF.getContents().size();
+ bool IsAbs = LF.getValue().EvaluateAsAbsolute(Value, Layout);
+ (void)IsAbs;
+ assert(IsAbs);
+ SmallString<8> &Data = LF.getContents();
+ Data.clear();
+ raw_svector_ostream OSE(Data);
+ if (LF.isSigned())
+ encodeSLEB128(Value, OSE);
+ else
+ encodeULEB128(Value, OSE);
+ OSE.flush();
+ return OldSize != LF.getContents().size();
+}
- OS << "<MCAlignFragment ";
- this->MCFragment::dump();
- OS << "\n ";
- OS << " Alignment:" << getAlignment()
- << " Value:" << getValue() << " ValueSize:" << getValueSize()
- << " MaxBytesToEmit:" << getMaxBytesToEmit() << ">";
+bool MCAssembler::relaxDwarfLineAddr(MCAsmLayout &Layout,
+ MCDwarfLineAddrFragment &DF) {
+ MCContext &Context = Layout.getAssembler().getContext();
+ int64_t AddrDelta = 0;
+ uint64_t OldSize = DF.getContents().size();
+ bool IsAbs = DF.getAddrDelta().EvaluateAsAbsolute(AddrDelta, Layout);
+ (void)IsAbs;
+ assert(IsAbs);
+ int64_t LineDelta;
+ LineDelta = DF.getLineDelta();
+ SmallString<8> &Data = DF.getContents();
+ Data.clear();
+ raw_svector_ostream OSE(Data);
+ MCDwarfLineAddr::Encode(Context, LineDelta, AddrDelta, OSE);
+ OSE.flush();
+ return OldSize != Data.size();
}
-void MCDataFragment::dump() {
- raw_ostream &OS = llvm::errs();
+bool MCAssembler::relaxDwarfCallFrameFragment(MCAsmLayout &Layout,
+ MCDwarfCallFrameFragment &DF) {
+ MCContext &Context = Layout.getAssembler().getContext();
+ int64_t AddrDelta = 0;
+ uint64_t OldSize = DF.getContents().size();
+ bool IsAbs = DF.getAddrDelta().EvaluateAsAbsolute(AddrDelta, Layout);
+ (void)IsAbs;
+ assert(IsAbs);
+ SmallString<8> &Data = DF.getContents();
+ Data.clear();
+ raw_svector_ostream OSE(Data);
+ MCDwarfFrameEmitter::EncodeAdvanceLoc(Context, AddrDelta, OSE);
+ OSE.flush();
+ return OldSize != Data.size();
+}
- OS << "<MCDataFragment ";
- this->MCFragment::dump();
- OS << "\n ";
- OS << " Contents:[";
- for (unsigned i = 0, e = getContents().size(); i != e; ++i) {
- if (i) OS << ",";
- OS << hexdigit((Contents[i] >> 4) & 0xF) << hexdigit(Contents[i] & 0xF);
- }
- OS << "] (" << getContents().size() << " bytes)";
-
- if (!getFixups().empty()) {
- OS << ",\n ";
- OS << " Fixups:[";
- for (fixup_iterator it = fixup_begin(), ie = fixup_end(); it != ie; ++it) {
- if (it != fixup_begin()) OS << ",\n ";
- OS << *it;
+bool MCAssembler::layoutSectionOnce(MCAsmLayout &Layout, MCSectionData &SD) {
+ // Holds the first fragment which needed relaxing during this layout. It will
+ // remain NULL if none were relaxed.
+ // When a fragment is relaxed, all the fragments following it should get
+ // invalidated because their offset is going to change.
+ MCFragment *FirstRelaxedFragment = NULL;
+
+ // Attempt to relax all the fragments in the section.
+ for (MCSectionData::iterator I = SD.begin(), IE = SD.end(); I != IE; ++I) {
+ // Check if this is a fragment that needs relaxation.
+ bool RelaxedFrag = false;
+ switch(I->getKind()) {
+ default:
+ break;
+ case MCFragment::FT_Relaxable:
+ assert(!getRelaxAll() &&
+ "Did not expect a MCRelaxableFragment in RelaxAll mode");
+ RelaxedFrag = relaxInstruction(Layout, *cast<MCRelaxableFragment>(I));
+ break;
+ case MCFragment::FT_Dwarf:
+ RelaxedFrag = relaxDwarfLineAddr(Layout,
+ *cast<MCDwarfLineAddrFragment>(I));
+ break;
+ case MCFragment::FT_DwarfFrame:
+ RelaxedFrag =
+ relaxDwarfCallFrameFragment(Layout,
+ *cast<MCDwarfCallFrameFragment>(I));
+ break;
+ case MCFragment::FT_LEB:
+ RelaxedFrag = relaxLEB(Layout, *cast<MCLEBFragment>(I));
+ break;
}
- OS << "]";
+ if (RelaxedFrag && !FirstRelaxedFragment)
+ FirstRelaxedFragment = I;
}
-
- OS << ">";
+ if (FirstRelaxedFragment) {
+ Layout.invalidateFragmentsFrom(FirstRelaxedFragment);
+ return true;
+ }
+ return false;
}
-void MCFillFragment::dump() {
- raw_ostream &OS = llvm::errs();
+bool MCAssembler::layoutOnce(MCAsmLayout &Layout) {
+ ++stats::RelaxationSteps;
+
+ bool WasRelaxed = false;
+ for (iterator it = begin(), ie = end(); it != ie; ++it) {
+ MCSectionData &SD = *it;
+ while (layoutSectionOnce(Layout, SD))
+ WasRelaxed = true;
+ }
- OS << "<MCFillFragment ";
- this->MCFragment::dump();
- OS << "\n ";
- OS << " Value:" << getValue() << " ValueSize:" << getValueSize()
- << " Count:" << getCount() << ">";
+ return WasRelaxed;
}
-void MCOrgFragment::dump() {
- raw_ostream &OS = llvm::errs();
+void MCAssembler::finishLayout(MCAsmLayout &Layout) {
+ // The layout is done. Mark every fragment as valid.
+ for (unsigned int i = 0, n = Layout.getSectionOrder().size(); i != n; ++i) {
+ Layout.getFragmentOffset(&*Layout.getSectionOrder()[i]->rbegin());
+ }
+}
+
+// Debugging methods
+
+namespace llvm {
+
+raw_ostream &operator<<(raw_ostream &OS, const MCFixup &AF) {
+ OS << "<MCFixup" << " Offset:" << AF.getOffset()
+ << " Value:" << *AF.getValue()
+ << " Kind:" << AF.getKind() << ">";
+ return OS;
+}
- OS << "<MCOrgFragment ";
- this->MCFragment::dump();
- OS << "\n ";
- OS << " Offset:" << getOffset() << " Value:" << getValue() << ">";
}
-void MCZeroFillFragment::dump() {
+#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
+void MCFragment::dump() {
raw_ostream &OS = llvm::errs();
- OS << "<MCZeroFillFragment ";
- this->MCFragment::dump();
- OS << "\n ";
- OS << " Size:" << getSize() << " Alignment:" << getAlignment() << ">";
+ OS << "<";
+ switch (getKind()) {
+ case MCFragment::FT_Align: OS << "MCAlignFragment"; break;
+ case MCFragment::FT_Data: OS << "MCDataFragment"; break;
+ case MCFragment::FT_CompactEncodedInst:
+ OS << "MCCompactEncodedInstFragment"; break;
+ case MCFragment::FT_Fill: OS << "MCFillFragment"; break;
+ case MCFragment::FT_Relaxable: OS << "MCRelaxableFragment"; break;
+ case MCFragment::FT_Org: OS << "MCOrgFragment"; break;
+ case MCFragment::FT_Dwarf: OS << "MCDwarfFragment"; break;
+ case MCFragment::FT_DwarfFrame: OS << "MCDwarfCallFrameFragment"; break;
+ case MCFragment::FT_LEB: OS << "MCLEBFragment"; break;
+ }
+
+ OS << "<MCFragment " << (void*) this << " LayoutOrder:" << LayoutOrder
+ << " Offset:" << Offset
+ << " HasInstructions:" << hasInstructions()
+ << " BundlePadding:" << static_cast<unsigned>(getBundlePadding()) << ">";
+
+ switch (getKind()) {
+ case MCFragment::FT_Align: {
+ const MCAlignFragment *AF = cast<MCAlignFragment>(this);
+ if (AF->hasEmitNops())
+ OS << " (emit nops)";
+ OS << "\n ";
+ OS << " Alignment:" << AF->getAlignment()
+ << " Value:" << AF->getValue() << " ValueSize:" << AF->getValueSize()
+ << " MaxBytesToEmit:" << AF->getMaxBytesToEmit() << ">";
+ break;
+ }
+ case MCFragment::FT_Data: {
+ const MCDataFragment *DF = cast<MCDataFragment>(this);
+ OS << "\n ";
+ OS << " Contents:[";
+ const SmallVectorImpl<char> &Contents = DF->getContents();
+ for (unsigned i = 0, e = Contents.size(); i != e; ++i) {
+ if (i) OS << ",";
+ OS << hexdigit((Contents[i] >> 4) & 0xF) << hexdigit(Contents[i] & 0xF);
+ }
+ OS << "] (" << Contents.size() << " bytes)";
+
+ if (DF->fixup_begin() != DF->fixup_end()) {
+ OS << ",\n ";
+ OS << " Fixups:[";
+ for (MCDataFragment::const_fixup_iterator it = DF->fixup_begin(),
+ ie = DF->fixup_end(); it != ie; ++it) {
+ if (it != DF->fixup_begin()) OS << ",\n ";
+ OS << *it;
+ }
+ OS << "]";
+ }
+ break;
+ }
+ case MCFragment::FT_CompactEncodedInst: {
+ const MCCompactEncodedInstFragment *CEIF =
+ cast<MCCompactEncodedInstFragment>(this);
+ OS << "\n ";
+ OS << " Contents:[";
+ const SmallVectorImpl<char> &Contents = CEIF->getContents();
+ for (unsigned i = 0, e = Contents.size(); i != e; ++i) {
+ if (i) OS << ",";
+ OS << hexdigit((Contents[i] >> 4) & 0xF) << hexdigit(Contents[i] & 0xF);
+ }
+ OS << "] (" << Contents.size() << " bytes)";
+ break;
+ }
+ case MCFragment::FT_Fill: {
+ const MCFillFragment *FF = cast<MCFillFragment>(this);
+ OS << " Value:" << FF->getValue() << " ValueSize:" << FF->getValueSize()
+ << " Size:" << FF->getSize();
+ break;
+ }
+ case MCFragment::FT_Relaxable: {
+ const MCRelaxableFragment *F = cast<MCRelaxableFragment>(this);
+ OS << "\n ";
+ OS << " Inst:";
+ F->getInst().dump_pretty(OS);
+ break;
+ }
+ case MCFragment::FT_Org: {
+ const MCOrgFragment *OF = cast<MCOrgFragment>(this);
+ OS << "\n ";
+ OS << " Offset:" << OF->getOffset() << " Value:" << OF->getValue();
+ break;
+ }
+ case MCFragment::FT_Dwarf: {
+ const MCDwarfLineAddrFragment *OF = cast<MCDwarfLineAddrFragment>(this);
+ OS << "\n ";
+ OS << " AddrDelta:" << OF->getAddrDelta()
+ << " LineDelta:" << OF->getLineDelta();
+ break;
+ }
+ case MCFragment::FT_DwarfFrame: {
+ const MCDwarfCallFrameFragment *CF = cast<MCDwarfCallFrameFragment>(this);
+ OS << "\n ";
+ OS << " AddrDelta:" << CF->getAddrDelta();
+ break;
+ }
+ case MCFragment::FT_LEB: {
+ const MCLEBFragment *LF = cast<MCLEBFragment>(this);
+ OS << "\n ";
+ OS << " Value:" << LF->getValue() << " Signed:" << LF->isSigned();
+ break;
+ }
+ }
+ OS << ">";
}
void MCSectionData::dump() {
raw_ostream &OS = llvm::errs();
OS << "<MCSectionData";
- OS << " Alignment:" << getAlignment() << " Address:" << Address
- << " Size:" << Size << " FileSize:" << FileSize
+ OS << " Alignment:" << getAlignment()
<< " Fragments:[\n ";
for (iterator it = begin(), ie = end(); it != ie; ++it) {
if (it != begin()) OS << ",\n ";
}
OS << "]>\n";
}
+#endif
+
+// anchors for MC*Fragment vtables
+void MCEncodedFragment::anchor() { }
+void MCEncodedFragmentWithFixups::anchor() { }
+void MCDataFragment::anchor() { }
+void MCCompactEncodedInstFragment::anchor() { }
+void MCRelaxableFragment::anchor() { }
+void MCAlignFragment::anchor() { }
+void MCFillFragment::anchor() { }
+void MCOrgFragment::anchor() { }
+void MCLEBFragment::anchor() { }
+void MCDwarfLineAddrFragment::anchor() { }
+void MCDwarfCallFrameFragment::anchor() { }
projects / oota-llvm.git / blobdiff