#define DEBUG_TYPE "assembler"
#include "llvm/MC/MCAssembler.h"
#include "llvm/MC/MCAsmLayout.h"
+#include "llvm/MC/MCCodeEmitter.h"
#include "llvm/MC/MCExpr.h"
-#include "llvm/MC/MCSectionMachO.h"
+#include "llvm/MC/MCObjectWriter.h"
#include "llvm/MC/MCSymbol.h"
#include "llvm/MC/MCValue.h"
-#include "llvm/ADT/DenseMap.h"
-#include "llvm/ADT/SmallString.h"
+#include "llvm/ADT/OwningPtr.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/ADT/StringExtras.h"
-#include "llvm/ADT/StringMap.h"
#include "llvm/ADT/Twine.h"
+#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorHandling.h"
-#include "llvm/Support/MachO.h"
#include "llvm/Support/raw_ostream.h"
-#include "llvm/Support/Debug.h"
#include "llvm/Target/TargetRegistry.h"
#include "llvm/Target/TargetAsmBackend.h"
-// FIXME: Gross.
-#include "../Target/X86/X86FixupKinds.h"
-
#include <vector>
using namespace llvm;
-class MachObjectWriter;
-
+namespace {
+namespace stats {
STATISTIC(EmittedFragments, "Number of emitted assembler fragments");
+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");
+STATISTIC(SectionLayouts, "Number of section layouts");
+}
+}
// 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);
- return (SMO.getType() == 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(0)
+ {
+ // Compute the section layout order. Virtual sections must go last.
+ for (MCAssembler::iterator it = Asm.begin(), ie = Asm.end(); it != ie; ++it)
+ if (!Asm.getBackend().isVirtualSection(it->getSection()))
+ SectionOrder.push_back(&*it);
+ for (MCAssembler::iterator it = Asm.begin(), ie = Asm.end(); it != ie; ++it)
+ if (Asm.getBackend().isVirtualSection(it->getSection()))
+ SectionOrder.push_back(&*it);
}
-static bool isFixupKindPCRel(unsigned Kind) {
- switch (Kind) {
- default:
- return false;
- case X86::reloc_pcrel_1byte:
- case X86::reloc_pcrel_4byte:
- case X86::reloc_riprel_4byte:
+bool MCAsmLayout::isSectionUpToDate(const MCSectionData *SD) const {
+ // The first section is always up-to-date.
+ unsigned Index = SD->getLayoutOrder();
+ if (!Index)
return true;
- }
-}
-
-class MachObjectWriter {
- // See <mach-o/loader.h>.
- enum {
- Header_Magic32 = 0xFEEDFACE,
- Header_Magic64 = 0xFEEDFACF
- };
-
- enum {
- Header32Size = 28,
- Header64Size = 32,
- SegmentLoadCommand32Size = 56,
- SegmentLoadCommand64Size = 72,
- Section32Size = 68,
- Section64Size = 80,
- SymtabLoadCommandSize = 24,
- DysymtabLoadCommandSize = 80,
- Nlist32Size = 12,
- Nlist64Size = 16,
- RelocationInfoSize = 8
- };
-
- enum HeaderFileType {
- HFT_Object = 0x1
- };
-
- enum HeaderFlags {
- HF_SubsectionsViaSymbols = 0x2000
- };
-
- enum LoadCommandType {
- LCT_Segment = 0x1,
- LCT_Symtab = 0x2,
- LCT_Dysymtab = 0xb,
- LCT_Segment64 = 0x19
- };
-
- // 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;
- unsigned Is64Bit : 1;
- unsigned IsLSB : 1;
-
-public:
- MachObjectWriter(raw_ostream &_OS, bool _Is64Bit, bool _IsLSB = true)
- : OS(_OS), Is64Bit(_Is64Bit), 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 WriteHeader(unsigned NumLoadCommands, unsigned LoadCommandsSize,
- bool SubsectionsViaSymbols) {
- uint32_t Flags = 0;
- if (SubsectionsViaSymbols)
- Flags |= HF_SubsectionsViaSymbols;
-
- // struct mach_header (28 bytes) or
- // struct mach_header_64 (32 bytes)
-
- uint64_t Start = OS.tell();
- (void) Start;
-
- Write32(Is64Bit ? Header_Magic64 : Header_Magic32);
-
- // FIXME: Support cputype.
- Write32(Is64Bit ? MachO::CPUTypeX86_64 : 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);
- if (Is64Bit)
- Write32(0); // reserved
-
- assert(OS.tell() - Start == Is64Bit ? Header64Size : Header32Size);
- }
-
- /// WriteSegmentLoadCommand - Write a segment load command.
- ///
- /// \arg NumSections - The number of sections in this segment.
- /// \arg SectionDataSize - The total size of the sections.
- void WriteSegmentLoadCommand(unsigned NumSections,
- uint64_t VMSize,
- uint64_t SectionDataStartOffset,
- uint64_t SectionDataSize) {
- // struct segment_command (56 bytes) or
- // struct segment_command_64 (72 bytes)
-
- uint64_t Start = OS.tell();
- (void) Start;
-
- unsigned SegmentLoadCommandSize = Is64Bit ? SegmentLoadCommand64Size :
- SegmentLoadCommand32Size;
- Write32(Is64Bit ? LCT_Segment64 : LCT_Segment);
- Write32(SegmentLoadCommandSize +
- NumSections * (Is64Bit ? Section64Size : Section32Size));
-
- WriteString("", 16);
- if (Is64Bit) {
- Write64(0); // vmaddr
- Write64(VMSize); // vmsize
- Write64(SectionDataStartOffset); // file offset
- Write64(SectionDataSize); // file size
- } else {
- 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 == SegmentLoadCommandSize);
- }
-
- void WriteSection(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) or
- // struct section_64 (80 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);
- if (Is64Bit) {
- Write64(SD.getAddress()); // address
- Write64(SD.getSize()); // size
- } else {
- 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
- if (Is64Bit)
- Write32(0); // reserved3
-
- assert(OS.tell() - Start == Is64Bit ? Section64Size : 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 WriteNlist(MachSymbolData &MSD) {
- MCSymbolData &Data = *MSD.SymbolData;
- const MCSymbol &Symbol = Data.getSymbol();
- uint8_t Type = 0;
- uint16_t Flags = Data.getFlags();
- uint32_t Address = 0;
-
- // 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.getAddress();
- }
- } 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);
- }
- }
-
- // struct nlist (12 bytes)
-
- Write32(MSD.StringIndex);
- Write8(Type);
- Write8(MSD.SectionIndex);
-
- // The Mach-O streamer uses the lowest 16-bits of the flags for the 'desc'
- // value.
- Write16(Flags);
- if (Is64Bit)
- Write64(Address);
- else
- Write32(Address);
- }
-
- struct MachRelocationEntry {
- uint32_t Word0;
- uint32_t Word1;
- };
- void ComputeScatteredRelocationInfo(MCAssembler &Asm, MCFragment &Fragment,
- MCAsmFixup &Fixup,
- const MCValue &Target,
- 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()->getSymbol();
- MCSymbolData *A_SD = &Asm.getSymbolData(*A);
-
- if (!A_SD->getFragment())
- llvm_report_error("symbol '" + A->getName() +
- "' can not be undefined in a subtraction expression");
-
- uint32_t Value = A_SD->getAddress();
- uint32_t Value2 = 0;
-
- if (const MCSymbolRefExpr *B = Target.getSymB()) {
- MCSymbolData *B_SD = &Asm.getSymbolData(B->getSymbol());
-
- if (!B_SD->getFragment())
- llvm_report_error("symbol '" + B->getSymbol().getName() +
- "' can not be undefined in a subtraction expression");
-
- // Select the appropriate difference relocation type.
- //
- // Note that there is no longer any semantic difference between these two
- // relocation types from the linkers point of view, this is done solely
- // for pedantic compatibility with 'as'.
- Type = A_SD->isExternal() ? RIT_Difference : RIT_LocalDifference;
- Value2 = B_SD->getAddress();
- }
-
- MachRelocationEntry MRE;
- MRE.Word0 = ((Address << 0) |
- (Type << 24) |
- (Log2Size << 28) |
- (IsPCRel << 30) |
- RF_Scattered);
- MRE.Word1 = Value;
- Relocs.push_back(MRE);
-
- if (Type == RIT_Difference || 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);
- }
- }
-
- void ComputeRelocationInfo(MCAssembler &Asm, MCDataFragment &Fragment,
- MCAsmFixup &Fixup,
- std::vector<MachRelocationEntry> &Relocs) {
- unsigned IsPCRel = isFixupKindPCRel(Fixup.Kind);
- unsigned Log2Size = getFixupKindLog2Size(Fixup.Kind);
-
- // FIXME: Share layout object.
- MCAsmLayout Layout(Asm);
-
- // Evaluate the fixup; if the value was resolved, no relocation is needed.
- MCValue Target;
- if (Asm.EvaluateFixup(Layout, Fixup, &Fragment, Target, Fixup.FixedValue))
- return;
-
- // If this is a difference or a defined symbol plus an offset, then we need
- // a scattered relocation entry.
- uint32_t Offset = Target.getConstant();
- if (IsPCRel)
- Offset += 1 << Log2Size;
- if (Target.getSymB() ||
- (Target.getSymA() && !Target.getSymA()->getSymbol().isUndefined() &&
- Offset))
- return ComputeScatteredRelocationInfo(Asm, Fragment, Fixup, Target,
- Relocs);
-
- // See <reloc.h>.
- uint32_t Address = Fragment.getOffset() + Fixup.Offset;
- uint32_t Value = 0;
- unsigned Index = 0;
- unsigned IsExtern = 0;
- unsigned Type = 0;
-
- if (Target.isAbsolute()) { // constant
- // SymbolNum of 0 indicates the absolute section.
- //
- // FIXME: Currently, these are never generated (see code below). I cannot
- // find a case where they are actually emitted.
- Type = RIT_Vanilla;
- Value = 0;
- } else {
- const MCSymbol *Symbol = &Target.getSymA()->getSymbol();
- MCSymbolData *SD = &Asm.getSymbolData(*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->getAddress();
- }
-
- Type = RIT_Vanilla;
- }
-
- // 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);
- }
-
- void BindIndirectSymbols(MCAssembler &Asm) {
- // 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());
-
- if (Section.getType() != MCSectionMachO::S_NON_LAZY_SYMBOL_POINTERS)
- continue;
-
- Asm.getOrCreateSymbolData(*it->Symbol);
- }
+ // Otherwise, sections are always implicitly computed when the preceeding
+ // fragment is layed out.
+ const MCSectionData *Prev = getSectionOrder()[Index - 1];
+ return isFragmentUpToDate(&(Prev->getFragmentList().back()));
+}
- // 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());
+bool MCAsmLayout::isFragmentUpToDate(const MCFragment *F) const {
+ return (LastValidFragment &&
+ F->getLayoutOrder() <= LastValidFragment->getLayoutOrder());
+}
- if (Section.getType() != MCSectionMachO::S_LAZY_SYMBOL_POINTERS &&
- Section.getType() != MCSectionMachO::S_SYMBOL_STUBS)
- continue;
+void MCAsmLayout::UpdateForSlide(MCFragment *F, int SlideAmount) {
+ // If this fragment wasn't already up-to-date, we don't need to do anything.
+ if (!isFragmentUpToDate(F))
+ return;
- // Set the symbol type to undefined lazy, but only on construction.
- //
- // FIXME: Do not hardcode.
- bool Created;
- MCSymbolData &Entry = Asm.getOrCreateSymbolData(*it->Symbol, &Created);
- if (Created)
- Entry.setFlags(Entry.getFlags() | 0x0001);
+ // Otherwise, reset the last valid fragment to the predecessor of the
+ // invalidated fragment.
+ LastValidFragment = F->getPrevNode();
+ if (!LastValidFragment) {
+ unsigned Index = F->getParent()->getLayoutOrder();
+ if (Index != 0) {
+ MCSectionData *Prev = getSectionOrder()[Index - 1];
+ LastValidFragment = &(Prev->getFragmentList().back());
}
}
+}
- /// 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 non-linker visible symbols.
- if (!Asm.isSymbolLinkerVisible(it))
- 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 non-linker visible symbols.
- if (!Asm.isSymbolLinkerVisible(it))
- 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);
- }
+void MCAsmLayout::EnsureValid(const MCFragment *F) const {
+ // Advance the layout position until the fragment is up-to-date.
+ while (!isFragmentUpToDate(F)) {
+ // Advance to the next fragment.
+ MCFragment *Cur = LastValidFragment;
+ if (Cur)
+ Cur = Cur->getNextNode();
+ if (!Cur) {
+ unsigned NextIndex = 0;
+ if (LastValidFragment)
+ NextIndex = LastValidFragment->getParent()->getLayoutOrder() + 1;
+ Cur = SectionOrder[NextIndex]->begin();
}
- // 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';
+ const_cast<MCAsmLayout*>(this)->LayoutFragment(Cur);
}
+}
- void WriteObject(MCAssembler &Asm) {
- unsigned NumSections = Asm.size();
-
- // Create symbol data for any indirect symbols.
- BindIndirectSymbols(Asm);
-
- // 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 = Is64Bit ?
- SegmentLoadCommand64Size + NumSections * Section64Size :
- SegmentLoadCommand32Size + NumSections * Section32Size;
-
- // Add the symbol table load command sizes, if used.
- if (NumSymbols) {
- NumLoadCommands += 2;
- LoadCommandsSize += SymtabLoadCommandSize + DysymtabLoadCommandSize;
- }
-
- // Compute the total size of the section data, as well as its file size and
- // vm size.
- uint64_t SectionDataStart = (Is64Bit ? Header64Size : 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());
- }
+void MCAsmLayout::FragmentReplaced(MCFragment *Src, MCFragment *Dst) {
+ if (LastValidFragment == Src)
+ LastValidFragment = Dst;
- // The section data is padded to 4 bytes.
- //
- // FIXME: Is this machine dependent?
- unsigned SectionDataPadding = OffsetToAlignment(SectionDataFileSize, 4);
- SectionDataFileSize += SectionDataPadding;
-
- // Write the prolog, starting with the header and load command...
- WriteHeader(NumLoadCommands, LoadCommandsSize,
- Asm.getSubsectionsViaSymbols());
- WriteSegmentLoadCommand(NumSections, VMSize,
- SectionDataStart, SectionDataSize);
-
- // ... and then the section headers.
- //
- // 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],
- RelocInfos);
-
- unsigned NumRelocs = RelocInfos.size() - NumRelocsStart;
- uint64_t SectionStart = SectionDataStart + SD.getAddress();
- WriteSection(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 * (Is64Bit ? Nlist64Size :
- Nlist32Size);
- WriteSymtabLoadCommand(SymbolTableOffset, NumSymTabSymbols,
- StringTableOffset, StringTable.size());
-
- WriteDysymtabLoadCommand(FirstLocalSymbol, NumLocalSymbols,
- FirstExternalSymbol, NumExternalSymbols,
- FirstUndefinedSymbol, NumUndefinedSymbols,
- IndirectSymbolOffset, NumIndirectSymbols);
- }
+ Dst->Offset = Src->Offset;
+ Dst->EffectiveSize = Src->EffectiveSize;
+}
- // Write the actual section data.
- for (MCAssembler::iterator it = Asm.begin(), ie = Asm.end(); it != ie; ++it)
- WriteFileData(OS, *it, *this);
+uint64_t MCAsmLayout::getFragmentAddress(const MCFragment *F) const {
+ assert(F->getParent() && "Missing section()!");
+ return getSectionAddress(F->getParent()) + getFragmentOffset(F);
+}
- // Write the extra padding.
- WriteZeros(SectionDataPadding);
+uint64_t MCAsmLayout::getFragmentEffectiveSize(const MCFragment *F) const {
+ EnsureValid(F);
+ assert(F->EffectiveSize != ~UINT64_C(0) && "Address not set!");
+ return F->EffectiveSize;
+}
- // Write the relocation entries.
- for (unsigned i = 0, e = RelocInfos.size(); i != e; ++i) {
- Write32(RelocInfos[i].Word0);
- Write32(RelocInfos[i].Word1);
- }
+uint64_t MCAsmLayout::getFragmentOffset(const MCFragment *F) const {
+ EnsureValid(F);
+ assert(F->Offset != ~UINT64_C(0) && "Address not set!");
+ return F->Offset;
+}
- // 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());
- if (Section.getType() == MCSectionMachO::S_NON_LAZY_SYMBOL_POINTERS) {
- // If this symbol is defined and internal, mark it as such.
- if (it->Symbol->isDefined() &&
- !Asm.getSymbolData(*it->Symbol).isExternal()) {
- uint32_t Flags = ISF_Local;
- if (it->Symbol->isAbsolute())
- Flags |= ISF_Absolute;
- Write32(Flags);
- continue;
- }
- }
+uint64_t MCAsmLayout::getSymbolAddress(const MCSymbolData *SD) const {
+ assert(SD->getFragment() && "Invalid getAddress() on undefined symbol!");
+ return getFragmentAddress(SD->getFragment()) + SD->getOffset();
+}
- Write32(Asm.getSymbolData(*it->Symbol).getIndex());
- }
+uint64_t MCAsmLayout::getSectionAddress(const MCSectionData *SD) const {
+ EnsureValid(SD->begin());
+ assert(SD->Address != ~UINT64_C(0) && "Address not set!");
+ return SD->Address;
+}
- // FIXME: Check that offsets match computed ones.
+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) + getFragmentEffectiveSize(&F);
+}
- // Write the symbol table entries.
- for (unsigned i = 0, e = LocalSymbolData.size(); i != e; ++i)
- WriteNlist(LocalSymbolData[i]);
- for (unsigned i = 0, e = ExternalSymbolData.size(); i != e; ++i)
- WriteNlist(ExternalSymbolData[i]);
- for (unsigned i = 0, e = UndefinedSymbolData.size(); i != e; ++i)
- WriteNlist(UndefinedSymbolData[i]);
+uint64_t MCAsmLayout::getSectionFileSize(const MCSectionData *SD) const {
+ // Virtual sections have no file size.
+ if (getAssembler().getBackend().isVirtualSection(SD->getSection()))
+ return 0;
- // Write the string table.
- OS << StringTable.str();
- }
- }
+ // Otherwise, the file size is the same as the address space size.
+ return getSectionAddressSize(SD);
+}
- void ApplyFixup(const MCAsmFixup &Fixup, MCDataFragment &DF) {
- unsigned Size = 1 << getFixupKindLog2Size(Fixup.Kind);
+uint64_t MCAsmLayout::getSectionSize(const MCSectionData *SD) const {
+ // The logical size is the address space size minus any tail padding.
+ uint64_t Size = getSectionAddressSize(SD);
+ const MCAlignFragment *AF =
+ dyn_cast<MCAlignFragment>(&(SD->getFragmentList().back()));
+ if (AF && AF->hasOnlyAlignAddress())
+ Size -= getFragmentEffectiveSize(AF);
- // 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));
- }
-};
+ return Size;
+}
/* *** */
}
MCFragment::MCFragment(FragmentType _Kind, MCSectionData *_Parent)
- : Kind(_Kind),
- Parent(_Parent),
- FileSize(~UINT64_C(0))
+ : Kind(_Kind), Parent(_Parent), Atom(0), EffectiveSize(~UINT64_C(0))
{
if (Parent)
Parent->getFragmentList().push_back(this);
}
-MCFragment::~MCFragment() {
-}
-
-uint64_t MCFragment::getAddress() const {
- assert(getParent() && "Missing Section!");
- return getParent()->getAddress() + Offset;
-}
-
/* *** */
MCSectionData::MCSectionData() : Section(0) {}
: Section(&_Section),
Alignment(1),
Address(~UINT64_C(0)),
- Size(~UINT64_C(0)),
- FileSize(~UINT64_C(0)),
HasInstructions(false)
{
if (A)
/* *** */
MCAssembler::MCAssembler(MCContext &_Context, TargetAsmBackend &_Backend,
- raw_ostream &_OS)
- : Context(_Context), Backend(_Backend), OS(_OS), SubsectionsViaSymbols(false)
+ MCCodeEmitter &_Emitter, raw_ostream &_OS)
+ : Context(_Context), Backend(_Backend), Emitter(_Emitter),
+ OS(_OS), RelaxAll(false), SubsectionsViaSymbols(false)
{
}
}
static bool isScatteredFixupFullyResolvedSimple(const MCAssembler &Asm,
- const MCAsmFixup &Fixup,
- const MCDataFragment *DF,
+ const MCFixup &Fixup,
const MCValue Target,
const MCSection *BaseSection) {
// The effective fixup address is
// resolved. This also works in conjunction with absolutized .set, which
// requires the compiler to use .set to absolutize the differences between
// symbols which the compiler knows to be assembly time constants, so we don't
- // need to worry about consider symbol differences fully resolved.
+ // need to worry about considering symbol differences fully resolved.
// Non-relative fixups are only resolved if constant.
if (!BaseSection)
return true;
}
+static bool isScatteredFixupFullyResolved(const MCAssembler &Asm,
+ const MCAsmLayout &Layout,
+ const MCFixup &Fixup,
+ const MCValue Target,
+ const MCSymbolData *BaseSymbol) {
+ // The effective fixup address is
+ // addr(atom(A)) + offset(A)
+ // - addr(atom(B)) - offset(B)
+ // - addr(BaseSymbol) + <fixup offset from base symbol>
+ // and the offsets are not relocatable, so the fixup is fully resolved when
+ // addr(atom(A)) - addr(atom(B)) - addr(BaseSymbol) == 0.
+ //
+ // Note that "false" is almost always conservatively correct (it means we emit
+ // a relocation which is unnecessary), except when it would force us to emit a
+ // relocation which the target cannot encode.
+
+ const MCSymbolData *A_Base = 0, *B_Base = 0;
+ if (const MCSymbolRefExpr *A = Target.getSymA()) {
+ // Modified symbol references cannot be resolved.
+ if (A->getKind() != MCSymbolRefExpr::VK_None)
+ return false;
+
+ A_Base = Asm.getAtom(Layout, &Asm.getSymbolData(A->getSymbol()));
+ if (!A_Base)
+ return false;
+ }
+
+ if (const MCSymbolRefExpr *B = Target.getSymB()) {
+ // Modified symbol references cannot be resolved.
+ if (B->getKind() != MCSymbolRefExpr::VK_None)
+ return false;
+
+ B_Base = Asm.getAtom(Layout, &Asm.getSymbolData(B->getSymbol()));
+ if (!B_Base)
+ return false;
+ }
+
+ // If there is no base, A and B have to be the same atom for this fixup to be
+ // fully resolved.
+ if (!BaseSymbol)
+ return A_Base == B_Base;
+
+ // Otherwise, B must be missing and A must be the base.
+ return !B_Base && BaseSymbol == A_Base;
+}
+
bool MCAssembler::isSymbolLinkerVisible(const MCSymbolData *SD) const {
// Non-temporary labels should always be visible to the linker.
if (!SD->getSymbol().isTemporary())
SD->getFragment()->getParent()->getSection());
}
-const MCSymbolData *MCAssembler::getAtomForAddress(const MCSectionData *Section,
- uint64_t Address) const {
- const MCSymbolData *Best = 0;
- for (MCAssembler::const_symbol_iterator it = symbol_begin(),
- ie = symbol_end(); it != ie; ++it) {
- // Ignore non-linker visible symbols.
- if (!isSymbolLinkerVisible(it))
- continue;
-
- // Ignore symbols not in the same section.
- if (!it->getFragment() || it->getFragment()->getParent() != Section)
- continue;
-
- // Otherwise, find the closest symbol preceding this address (ties are
- // resolved in favor of the last defined symbol).
- if (it->getAddress() <= Address &&
- (!Best || it->getAddress() >= Best->getAddress()))
- Best = it;
- }
-
- return Best;
-}
-
-const MCSymbolData *MCAssembler::getAtom(const MCSymbolData *SD) const {
+const MCSymbolData *MCAssembler::getAtom(const MCAsmLayout &Layout,
+ const MCSymbolData *SD) const {
// Linker visible symbols define atoms.
if (isSymbolLinkerVisible(SD))
return SD;
if (!SD->getFragment())
return 0;
- // Otherwise, search by address.
- return getAtomForAddress(SD->getFragment()->getParent(), SD->getAddress());
+ // Non-linker visible symbols in sections which can't be atomized have no
+ // defining atom.
+ if (!getBackend().isSectionAtomizable(
+ SD->getFragment()->getParent()->getSection()))
+ return 0;
+
+ // Otherwise, return the atom for the containing fragment.
+ return SD->getFragment()->getAtom();
}
-bool MCAssembler::EvaluateFixup(const MCAsmLayout &Layout, MCAsmFixup &Fixup,
- MCDataFragment *DF,
+bool MCAssembler::EvaluateFixup(const MCAsmLayout &Layout,
+ const MCFixup &Fixup, const MCFragment *DF,
MCValue &Target, uint64_t &Value) const {
- if (!Fixup.Value->EvaluateAsRelocatable(Target, &Layout))
- llvm_report_error("expected relocatable expression");
+ ++stats::EvaluateFixup;
+
+ if (!Fixup.getValue()->EvaluateAsRelocatable(Target, &Layout))
+ report_fatal_error("expected relocatable expression");
// FIXME: How do non-scattered symbols work in ELF? I presume the linker
// doesn't support small relocations, but then under what criteria does the
Value = Target.getConstant();
- bool IsResolved = true, IsPCRel = isFixupKindPCRel(Fixup.Kind);
+ bool IsPCRel = Emitter.getFixupKindInfo(
+ Fixup.getKind()).Flags & MCFixupKindInfo::FKF_IsPCRel;
+ bool IsResolved = true;
if (const MCSymbolRefExpr *A = Target.getSymA()) {
if (A->getSymbol().isDefined())
- Value += getSymbolData(A->getSymbol()).getAddress();
+ Value += Layout.getSymbolAddress(&getSymbolData(A->getSymbol()));
else
IsResolved = false;
}
if (const MCSymbolRefExpr *B = Target.getSymB()) {
if (B->getSymbol().isDefined())
- Value -= getSymbolData(B->getSymbol()).getAddress();
+ Value -= Layout.getSymbolAddress(&getSymbolData(B->getSymbol()));
else
IsResolved = false;
}
// resolved; scattering may cause atoms to move.
if (IsResolved && getBackend().hasScatteredSymbols()) {
if (getBackend().hasReliableSymbolDifference()) {
- llvm_report_error("FIXME: Not yet implemented");
+ // If this is a PCrel relocation, find the base atom (identified by its
+ // symbol) that the fixup value is relative to.
+ const MCSymbolData *BaseSymbol = 0;
+ if (IsPCRel) {
+ BaseSymbol = DF->getAtom();
+ if (!BaseSymbol)
+ IsResolved = false;
+ }
+
+ if (IsResolved)
+ IsResolved = isScatteredFixupFullyResolved(*this, Layout, Fixup, Target,
+ BaseSymbol);
} else {
const MCSection *BaseSection = 0;
if (IsPCRel)
BaseSection = &DF->getParent()->getSection();
- IsResolved = isScatteredFixupFullyResolvedSimple(*this, Fixup, DF, Target,
+ IsResolved = isScatteredFixupFullyResolvedSimple(*this, Fixup, Target,
BaseSection);
}
}
if (IsPCRel)
- Value -= DF->getAddress() + Fixup.Offset;
+ Value -= Layout.getFragmentAddress(DF) + Fixup.getOffset();
return IsResolved;
}
-void MCAssembler::LayoutSection(MCSectionData &SD) {
- MCAsmLayout Layout(*this);
- uint64_t Address = SD.getAddress();
-
- for (MCSectionData::iterator it = SD.begin(), ie = SD.end(); it != ie; ++it) {
- MCFragment &F = *it;
+uint64_t MCAssembler::ComputeFragmentSize(MCAsmLayout &Layout,
+ const MCFragment &F,
+ uint64_t SectionAddress,
+ uint64_t FragmentOffset) const {
+ switch (F.getKind()) {
+ case MCFragment::FT_Data:
+ return cast<MCDataFragment>(F).getContents().size();
+ case MCFragment::FT_Fill:
+ return cast<MCFillFragment>(F).getSize();
+ case MCFragment::FT_Inst:
+ return cast<MCInstFragment>(F).getInstSize();
- F.setOffset(Address - SD.getAddress());
+ case MCFragment::FT_Align: {
+ const MCAlignFragment &AF = cast<MCAlignFragment>(F);
- // Evaluate fragment size.
- switch (F.getKind()) {
- case MCFragment::FT_Align: {
- MCAlignFragment &AF = cast<MCAlignFragment>(F);
+ assert((!AF.hasOnlyAlignAddress() || !AF.getNextNode()) &&
+ "Invalid OnlyAlignAddress bit, not the last fragment!");
- uint64_t Size = OffsetToAlignment(Address, AF.getAlignment());
- if (Size > AF.getMaxBytesToEmit())
- AF.setFileSize(0);
- else
- AF.setFileSize(Size);
- break;
- }
+ uint64_t Size = OffsetToAlignment(SectionAddress + FragmentOffset,
+ AF.getAlignment());
- case MCFragment::FT_Data:
- case MCFragment::FT_Fill:
- F.setFileSize(F.getMaxFileSize());
- break;
+ // Honor MaxBytesToEmit.
+ if (Size > AF.getMaxBytesToEmit())
+ return 0;
- case MCFragment::FT_Org: {
- MCOrgFragment &OF = cast<MCOrgFragment>(F);
+ return Size;
+ }
- int64_t TargetLocation;
- if (!OF.getOffset().EvaluateAsAbsolute(TargetLocation, &Layout))
- llvm_report_error("expected assembly-time absolute expression");
+ case MCFragment::FT_Org: {
+ const MCOrgFragment &OF = cast<MCOrgFragment>(F);
- // FIXME: We need a way to communicate this error.
- int64_t Offset = TargetLocation - F.getOffset();
- if (Offset < 0)
- llvm_report_error("invalid .org offset '" + Twine(TargetLocation) +
- "' (at offset '" + Twine(F.getOffset()) + "'");
+ // FIXME: We should compute this sooner, we don't want to recurse here, and
+ // we would like to be more functional.
+ int64_t TargetLocation;
+ if (!OF.getOffset().EvaluateAsAbsolute(TargetLocation, &Layout))
+ report_fatal_error("expected assembly-time absolute expression");
- F.setFileSize(Offset);
- break;
- }
+ // FIXME: We need a way to communicate this error.
+ int64_t Offset = TargetLocation - FragmentOffset;
+ if (Offset < 0)
+ report_fatal_error("invalid .org offset '" + Twine(TargetLocation) +
+ "' (at offset '" + Twine(FragmentOffset) + "'");
- case MCFragment::FT_ZeroFill: {
- MCZeroFillFragment &ZFF = cast<MCZeroFillFragment>(F);
+ return Offset;
+ }
+ }
- // 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());
+ assert(0 && "invalid fragment kind");
+ return 0;
+}
- // FIXME: This is misnamed.
- F.setFileSize(ZFF.getSize());
- break;
- }
- }
+void MCAsmLayout::LayoutFile() {
+ // Initialize the first section and set the valid fragment layout point. All
+ // actual layout computations are done lazily.
+ LastValidFragment = 0;
+ if (!getSectionOrder().empty())
+ getSectionOrder().front()->Address = 0;
+}
- Address += F.getFileSize();
+void MCAsmLayout::LayoutFragment(MCFragment *F) {
+ MCFragment *Prev = F->getPrevNode();
+
+ // We should never try to recompute something which is up-to-date.
+ assert(!isFragmentUpToDate(F) && "Attempt to recompute up-to-date fragment!");
+ // We should never try to compute the fragment layout if the section isn't
+ // up-to-date.
+ assert(isSectionUpToDate(F->getParent()) &&
+ "Attempt to compute fragment before it's section!");
+ // We should never try to compute the fragment layout if it's predecessor
+ // isn't up-to-date.
+ assert((!Prev || isFragmentUpToDate(Prev)) &&
+ "Attempt to compute fragment before it's predecessor!");
+
+ ++stats::FragmentLayouts;
+
+ // Compute the fragment start address.
+ uint64_t StartAddress = F->getParent()->Address;
+ uint64_t Address = StartAddress;
+ if (Prev)
+ Address += Prev->Offset + Prev->EffectiveSize;
+
+ // Compute fragment offset and size.
+ F->Offset = Address - StartAddress;
+ F->EffectiveSize = getAssembler().ComputeFragmentSize(*this, *F, StartAddress,
+ F->Offset);
+ LastValidFragment = F;
+
+ // If this is the last fragment in a section, update the next section address.
+ if (!F->getNextNode()) {
+ unsigned NextIndex = F->getParent()->getLayoutOrder() + 1;
+ if (NextIndex != getSectionOrder().size())
+ LayoutSection(getSectionOrder()[NextIndex]);
}
-
- // Set the section sizes.
- SD.setSize(Address - SD.getAddress());
- if (isVirtualSection(SD.getSection()))
- SD.setFileSize(0);
- else
- SD.setFileSize(Address - SD.getAddress());
}
-/// 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::LayoutSection(MCSectionData *SD) {
+ unsigned SectionOrderIndex = SD->getLayoutOrder();
+
+ ++stats::SectionLayouts;
- for (uint64_t i = 0; i < Count; i++)
- MOW.Write8 (uint8_t(Nops[Count - 1][i]));
+ // Compute the section start address.
+ uint64_t StartAddress = 0;
+ if (SectionOrderIndex) {
+ MCSectionData *Prev = getSectionOrder()[SectionOrderIndex - 1];
+ StartAddress = getSectionAddress(Prev) + getSectionAddressSize(Prev);
+ }
- return Count;
+ // Honor the section alignment requirements.
+ StartAddress = RoundUpToAlignment(StartAddress, SD->getAlignment());
+
+ // Set the section address.
+ SD->Address = StartAddress;
}
-/// 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();
+/// WriteFragmentData - Write the \arg F data to the output file.
+static void WriteFragmentData(const MCAssembler &Asm, const MCAsmLayout &Layout,
+ const MCFragment &F, MCObjectWriter *OW) {
+ uint64_t Start = OW->getStream().tell();
(void) Start;
- ++EmittedFragments;
+ ++stats::EmittedFragments;
// FIXME: Embed in fragments instead?
+ uint64_t FragmentSize = Layout.getFragmentEffectiveSize(&F);
switch (F.getKind()) {
case MCFragment::FT_Align: {
MCAlignFragment &AF = cast<MCAlignFragment>(F);
- uint64_t Count = AF.getFileSize() / AF.getValueSize();
+ uint64_t Count = FragmentSize / AF.getValueSize();
+
+ assert(AF.getValueSize() && "Invalid virtual align in concrete fragment!");
// 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;
+ // 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;
+ 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);
-
- // 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);
-
- OS << cast<MCDataFragment>(F).getContents().str();
+ assert(FragmentSize == DF.getContents().size() && "Invalid size!");
+ OW->WriteBytes(DF.getContents().str());
break;
}
case MCFragment::FT_Fill: {
MCFillFragment &FF = cast<MCFillFragment>(F);
- for (uint64_t i = 0, e = FF.getCount(); i != e; ++i) {
+
+ 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;
+ 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_Inst:
+ llvm_unreachable("unexpected inst fragment after lowering");
+ break;
+
case MCFragment::FT_Org: {
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!");
- break;
- }
}
- assert(OS.tell() - Start == F.getFileSize());
+ assert(OW->getStream().tell() - Start == FragmentSize);
}
-/// 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,
+ MCObjectWriter *OW) const {
// Ignore virtual sections.
- if (isVirtualSection(SD.getSection())) {
- assert(SD.getFileSize() == 0);
+ if (getBackend().isVirtualSection(SD->getSection())) {
+ 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:
+ assert(0 && "Invalid fragment in virtual section!");
+ case MCFragment::FT_Align:
+ assert(!cast<MCAlignFragment>(it)->getValueSize() &&
+ "Invalid align in virtual section!");
+ break;
+ case MCFragment::FT_Fill:
+ assert(!cast<MCFillFragment>(it)->getValueSize() &&
+ "Invalid fill in virtual section!");
+ break;
+ }
+ }
+
return;
}
- uint64_t Start = OS.tell();
+ uint64_t Start = OW->getStream().tell();
(void) Start;
- for (MCSectionData::const_iterator it = SD.begin(),
- ie = SD.end(); it != ie; ++it)
- WriteFileData(OS, *it, MOW);
-
- // Add section padding.
- assert(SD.getFileSize() >= SD.getSize() && "Invalid section sizes!");
- MOW.WriteZeros(SD.getFileSize() - SD.getSize());
+ for (MCSectionData::const_iterator it = SD->begin(),
+ ie = SD->end(); it != ie; ++it)
+ WriteFragmentData(*this, Layout, *it, OW);
- assert(OS.tell() - Start == SD.getFileSize());
+ assert(OW->getStream().tell() - Start == Layout.getSectionFileSize(SD));
}
void MCAssembler::Finish() {
llvm::errs() << "assembler backend - pre-layout\n--\n";
dump(); });
+ // Create the layout object.
+ MCAsmLayout Layout(*this);
+
+ // Insert additional align fragments for concrete sections to explicitly pad
+ // the previous section to match their alignment requirements. This is for
+ // 'gas' compatibility, it shouldn't strictly be necessary.
+ //
+ // FIXME: This may be Mach-O specific.
+ for (unsigned i = 1, e = Layout.getSectionOrder().size(); i < e; ++i) {
+ MCSectionData *SD = Layout.getSectionOrder()[i];
+
+ // Ignore sections without alignment requirements.
+ unsigned Align = SD->getAlignment();
+ if (Align <= 1)
+ continue;
+
+ // Ignore virtual sections, they don't cause file size modifications.
+ if (getBackend().isVirtualSection(SD->getSection()))
+ continue;
+
+ // Otherwise, create a new align fragment at the end of the previous
+ // section.
+ MCAlignFragment *AF = new MCAlignFragment(Align, 0, 1, Align,
+ Layout.getSectionOrder()[i - 1]);
+ AF->setOnlyAlignAddress(true);
+ }
+
+ // 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()) {
+ unsigned ValueSize = 1;
+ if (getBackend().isVirtualSection(it->getSection()))
+ ValueSize = 1;
+ new MCFillFragment(0, 1, 0, it);
+ }
+
+ it->setOrdinal(SectionIndex++);
+ }
+
+ // Assign layout order indices to sections and fragments.
+ unsigned FragmentIndex = 0;
+ for (unsigned i = 0, e = Layout.getSectionOrder().size(); i != e; ++i) {
+ MCSectionData *SD = Layout.getSectionOrder()[i];
+ SD->setLayoutOrder(i);
+
+ for (MCSectionData::iterator it2 = SD->begin(),
+ ie2 = SD->end(); it2 != ie2; ++it2)
+ it2->setLayoutOrder(FragmentIndex++);
+ }
+
// Layout until everything fits.
- while (LayoutOnce())
+ while (LayoutOnce(Layout))
continue;
DEBUG_WITH_TYPE("mc-dump", {
- llvm::errs() << "assembler backend - post-layout\n--\n";
+ 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 - final-layout\n--\n";
dump(); });
+ uint64_t StartOffset = OS.tell();
+ llvm::OwningPtr<MCObjectWriter> Writer(getBackend().createObjectWriter(OS));
+ if (!Writer)
+ report_fatal_error("unable to create object writer!");
+
+ // Allow the object writer a chance to perform post-layout binding (for
+ // example, to set the index fields in the symbol data).
+ Writer->ExecutePostLayoutBinding(*this);
+
+ // 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) {
+ MCDataFragment *DF = dyn_cast<MCDataFragment>(it2);
+ if (!DF)
+ continue;
+
+ for (MCDataFragment::fixup_iterator it3 = DF->fixup_begin(),
+ ie3 = DF->fixup_end(); it3 != ie3; ++it3) {
+ MCFixup &Fixup = *it3;
+
+ // Evaluate the fixup.
+ MCValue Target;
+ uint64_t FixedValue;
+ if (!EvaluateFixup(Layout, Fixup, DF, 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.
+ Writer->RecordRelocation(*this, Layout, DF, Fixup, Target,FixedValue);
+ }
+
+ getBackend().ApplyFixup(Fixup, *DF, FixedValue);
+ }
+ }
+ }
+
// Write the object file.
- //
- // FIXME: Factor out MCObjectWriter.
- bool Is64Bit = StringRef(getBackend().getTarget().getName()) == "x86-64";
- MachObjectWriter MOW(OS, Is64Bit);
- MOW.WriteObject(*this);
+ Writer->WriteObject(*this, Layout);
- OS.flush();
+ stats::ObjectBytes += OS.tell() - StartOffset;
}
-bool MCAssembler::FixupNeedsRelaxation(MCAsmFixup &Fixup, MCDataFragment *DF) {
- // FIXME: Share layout object.
- MCAsmLayout Layout(*this);
-
- // Currently we only need to relax X86::reloc_pcrel_1byte.
- if (unsigned(Fixup.Kind) != X86::reloc_pcrel_1byte)
- return false;
+bool MCAssembler::FixupNeedsRelaxation(const MCFixup &Fixup,
+ const MCFragment *DF,
+ const MCAsmLayout &Layout) const {
+ if (getRelaxAll())
+ return true;
// If we cannot resolve the fixup value, it requires relaxation.
MCValue Target;
return true;
// Otherwise, relax if the value is too big for a (signed) i8.
+ //
+ // FIXME: This is target dependent!
return int64_t(Value) != int64_t(int8_t(Value));
}
-bool MCAssembler::LayoutOnce() {
- // 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;
+bool MCAssembler::FragmentNeedsRelaxation(const MCInstFragment *IF,
+ 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(IF->getInst()))
+ return false;
- // Skip virtual sections.
- if (isVirtualSection(SD.getSection()))
- continue;
+ for (MCInstFragment::const_fixup_iterator it = IF->fixup_begin(),
+ ie = IF->fixup_end(); it != ie; ++it)
+ if (FixupNeedsRelaxation(*it, IF, Layout))
+ return true;
- // 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;
- }
+ return false;
+}
- // Layout the section fragments and its size.
- SD.setAddress(Address);
- LayoutSection(SD);
- Address += SD.getFileSize();
+bool MCAssembler::LayoutOnce(MCAsmLayout &Layout) {
+ ++stats::RelaxationSteps;
- Prev = &SD;
- }
+ // Layout the sections in order.
+ Layout.LayoutFile();
- // Layout the virtual sections.
+ // Scan for fragments that need relaxation.
+ bool WasRelaxed = false;
for (iterator it = begin(), ie = end(); it != ie; ++it) {
MCSectionData &SD = *it;
- if (!isVirtualSection(SD.getSection()))
- continue;
+ for (MCSectionData::iterator it2 = SD.begin(),
+ ie2 = SD.end(); it2 != ie2; ++it2) {
+ // Check if this is an instruction fragment that needs relaxation.
+ MCInstFragment *IF = dyn_cast<MCInstFragment>(it2);
+ if (!IF || !FragmentNeedsRelaxation(IF, Layout))
+ continue;
- // Align this section if necessary by adding padding bytes to the previous
- // section.
- if (uint64_t Pad = OffsetToAlignment(Address, it->getAlignment()))
- Address += Pad;
+ ++stats::RelaxedInstructions;
+
+ // FIXME-PERF: We could immediately lower out instructions if we can tell
+ // they are fully resolved, to avoid retesting on later passes.
- SD.setAddress(Address);
- LayoutSection(SD);
- Address += SD.getSize();
+ // Relax the fragment.
+
+ MCInst Relaxed;
+ getBackend().RelaxInstruction(IF->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 instruction fragment.
+ int SlideAmount = Code.size() - IF->getInstSize();
+ IF->setInst(Relaxed);
+ IF->getCode() = Code;
+ IF->getFixups().clear();
+ // FIXME: Eliminate copy.
+ for (unsigned i = 0, e = Fixups.size(); i != e; ++i)
+ IF->getFixups().push_back(Fixups[i]);
+
+ // Update the layout, and remember that we relaxed.
+ Layout.UpdateForSlide(IF, SlideAmount);
+ WasRelaxed = true;
+ }
}
- // Scan the fixups in order and relax any that don't fit.
+ return WasRelaxed;
+}
+
+void MCAssembler::FinishLayout(MCAsmLayout &Layout) {
+ // Lower out any instruction fragments, to simplify the fixup application and
+ // output.
+ //
+ // FIXME-PERF: We don't have to do this, but the assumption is that it is
+ // cheap (we will mostly end up eliminating fragments and appending on to data
+ // fragments), so the extra complexity downstream isn't worth it. Evaluate
+ // this assumption.
for (iterator it = begin(), ie = end(); it != ie; ++it) {
MCSectionData &SD = *it;
for (MCSectionData::iterator it2 = SD.begin(),
ie2 = SD.end(); it2 != ie2; ++it2) {
- MCDataFragment *DF = dyn_cast<MCDataFragment>(it2);
- if (!DF)
+ MCInstFragment *IF = dyn_cast<MCInstFragment>(it2);
+ if (!IF)
continue;
- for (MCDataFragment::fixup_iterator it3 = DF->fixup_begin(),
- ie3 = DF->fixup_end(); it3 != ie3; ++it3) {
- MCAsmFixup &Fixup = *it3;
-
- // Check whether we need to relax this fixup.
- if (!FixupNeedsRelaxation(Fixup, DF))
- continue;
-
- // Relax the instruction.
- //
- // FIXME: This is a huge temporary hack which just looks for x86
- // branches; the only thing we need to relax on x86 is
- // 'X86::reloc_pcrel_1byte'. Once we have MCInst fragments, this will be
- // replaced by a TargetAsmBackend hook (most likely tblgen'd) to relax
- // an individual MCInst.
- SmallVectorImpl<char> &C = DF->getContents();
- uint64_t PrevOffset = Fixup.Offset;
- unsigned Amt = 0;
-
- // jcc instructions
- if (unsigned(C[Fixup.Offset-1]) >= 0x70 &&
- unsigned(C[Fixup.Offset-1]) <= 0x7f) {
- C[Fixup.Offset] = C[Fixup.Offset-1] + 0x10;
- C[Fixup.Offset-1] = char(0x0f);
- ++Fixup.Offset;
- Amt = 4;
-
- // jmp rel8
- } else if (C[Fixup.Offset-1] == char(0xeb)) {
- C[Fixup.Offset-1] = char(0xe9);
- Amt = 3;
-
- } else
- llvm_unreachable("unknown 1 byte pcrel instruction!");
-
- Fixup.Value = MCBinaryExpr::Create(
- MCBinaryExpr::Sub, Fixup.Value,
- MCConstantExpr::Create(3, getContext()),
- getContext());
- C.insert(C.begin() + Fixup.Offset, Amt, char(0));
- Fixup.Kind = MCFixupKind(X86::reloc_pcrel_4byte);
-
- // Update the remaining fixups, which have slid.
- //
- // FIXME: This is bad for performance, but will be eliminated by the
- // move to MCInst specific fragments.
- ++it3;
- for (; it3 != ie3; ++it3)
- it3->Offset += Amt;
-
- // Update all the symbols for this fragment, which may have slid.
- //
- // FIXME: This is really really bad for performance, but will be
- // eliminated by the move to MCInst specific fragments.
- for (MCAssembler::symbol_iterator it = symbol_begin(),
- ie = symbol_end(); it != ie; ++it) {
- MCSymbolData &SD = *it;
-
- if (it->getFragment() != DF)
- continue;
-
- if (SD.getOffset() > PrevOffset)
- SD.setOffset(SD.getOffset() + Amt);
- }
-
- // Restart layout.
- //
- // FIXME: This is O(N^2), but will be eliminated once we have a smart
- // MCAsmLayout object.
- return true;
- }
+ // Create a new data fragment for the instruction.
+ //
+ // FIXME-PERF: Reuse previous data fragment if possible.
+ MCDataFragment *DF = new MCDataFragment();
+ SD.getFragmentList().insert(it2, DF);
+
+ // Update the data fragments layout data.
+ DF->setParent(IF->getParent());
+ DF->setAtom(IF->getAtom());
+ DF->setLayoutOrder(IF->getLayoutOrder());
+ Layout.FragmentReplaced(IF, DF);
+
+ // Copy in the data and the fixups.
+ DF->getContents().append(IF->getCode().begin(), IF->getCode().end());
+ for (unsigned i = 0, e = IF->getFixups().size(); i != e; ++i)
+ DF->getFixups().push_back(IF->getFixups()[i]);
+
+ // Delete the instruction fragment and update the iterator.
+ SD.getFragmentList().erase(IF);
+ it2 = DF;
}
}
-
- return false;
}
// Debugging methods
namespace llvm {
-raw_ostream &operator<<(raw_ostream &OS, const MCAsmFixup &AF) {
- OS << "<MCAsmFixup" << " Offset:" << AF.Offset << " Value:" << *AF.Value
- << " Kind:" << AF.Kind << ">";
+raw_ostream &operator<<(raw_ostream &OS, const MCFixup &AF) {
+ OS << "<MCFixup" << " Offset:" << AF.getOffset()
+ << " Value:" << *AF.getValue()
+ << " Kind:" << AF.getKind() << ">";
return OS;
}
void MCFragment::dump() {
raw_ostream &OS = llvm::errs();
- OS << "<MCFragment " << (void*) this << " Offset:" << Offset
- << " FileSize:" << FileSize;
-
- OS << ">";
-}
-
-void MCAlignFragment::dump() {
- raw_ostream &OS = llvm::errs();
-
- OS << "<MCAlignFragment ";
- this->MCFragment::dump();
- OS << "\n ";
- OS << " Alignment:" << getAlignment()
- << " Value:" << getValue() << " ValueSize:" << getValueSize()
- << " MaxBytesToEmit:" << getMaxBytesToEmit() << ">";
-}
+ OS << "<";
+ switch (getKind()) {
+ case MCFragment::FT_Align: OS << "MCAlignFragment"; break;
+ case MCFragment::FT_Data: OS << "MCDataFragment"; break;
+ case MCFragment::FT_Fill: OS << "MCFillFragment"; break;
+ case MCFragment::FT_Inst: OS << "MCInstFragment"; break;
+ case MCFragment::FT_Org: OS << "MCOrgFragment"; break;
+ }
-void MCDataFragment::dump() {
- raw_ostream &OS = llvm::errs();
+ OS << "<MCFragment " << (void*) this << " LayoutOrder:" << LayoutOrder
+ << " Offset:" << Offset << " EffectiveSize:" << EffectiveSize << ">";
- 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);
+ switch (getKind()) {
+ case MCFragment::FT_Align: {
+ const MCAlignFragment *AF = cast<MCAlignFragment>(this);
+ if (AF->hasEmitNops())
+ OS << " (emit nops)";
+ if (AF->hasOnlyAlignAddress())
+ OS << " (only align section)";
+ OS << "\n ";
+ OS << " Alignment:" << AF->getAlignment()
+ << " Value:" << AF->getValue() << " ValueSize:" << AF->getValueSize()
+ << " MaxBytesToEmit:" << AF->getMaxBytesToEmit() << ">";
+ break;
}
- 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;
+ 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 << "]";
+ OS << "] (" << Contents.size() << " bytes)";
+
+ if (!DF->getFixups().empty()) {
+ 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_Fill: {
+ const MCFillFragment *FF = cast<MCFillFragment>(this);
+ OS << " Value:" << FF->getValue() << " ValueSize:" << FF->getValueSize()
+ << " Size:" << FF->getSize();
+ break;
+ }
+ case MCFragment::FT_Inst: {
+ const MCInstFragment *IF = cast<MCInstFragment>(this);
+ OS << "\n ";
+ OS << " Inst:";
+ IF->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;
+ }
}
-
OS << ">";
}
-void MCFillFragment::dump() {
- raw_ostream &OS = llvm::errs();
-
- OS << "<MCFillFragment ";
- this->MCFragment::dump();
- OS << "\n ";
- OS << " Value:" << getValue() << " ValueSize:" << getValueSize()
- << " Count:" << getCount() << ">";
-}
-
-void MCOrgFragment::dump() {
- raw_ostream &OS = llvm::errs();
-
- OS << "<MCOrgFragment ";
- this->MCFragment::dump();
- OS << "\n ";
- OS << " Offset:" << getOffset() << " Value:" << getValue() << ">";
-}
-
-void MCZeroFillFragment::dump() {
- raw_ostream &OS = llvm::errs();
-
- OS << "<MCZeroFillFragment ";
- this->MCFragment::dump();
- OS << "\n ";
- OS << " Size:" << getSize() << " Alignment:" << getAlignment() << ">";
-}
-
void MCSectionData::dump() {
raw_ostream &OS = llvm::errs();
OS << "<MCSectionData";
OS << " Alignment:" << getAlignment() << " Address:" << Address
- << " Size:" << Size << " FileSize:" << FileSize
<< " Fragments:[\n ";
for (iterator it = begin(), ie = end(); it != ie; ++it) {
if (it != begin()) OS << ",\n ";
projects / oota-llvm.git / blobdiff