mirror of
https://github.com/c64scene-ar/llvm-6502.git
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2928c83b01
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@86251 91177308-0d34-0410-b5e6-96231b3b80d8
1211 lines
38 KiB
C++
1211 lines
38 KiB
C++
//===- lib/MC/MCAssembler.cpp - Assembler Backend Implementation ----------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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#define DEBUG_TYPE "assembler"
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#include "llvm/MC/MCAssembler.h"
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#include "llvm/MC/MCExpr.h"
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#include "llvm/MC/MCSectionMachO.h"
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#include "llvm/MC/MCSymbol.h"
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#include "llvm/MC/MCValue.h"
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#include "llvm/Target/TargetMachOWriterInfo.h"
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#include "llvm/ADT/DenseMap.h"
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#include "llvm/ADT/SmallString.h"
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#include "llvm/ADT/Statistic.h"
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#include "llvm/ADT/StringMap.h"
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#include "llvm/ADT/Twine.h"
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#include "llvm/Support/ErrorHandling.h"
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#include "llvm/Support/raw_ostream.h"
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#include <vector>
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using namespace llvm;
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class MachObjectWriter;
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STATISTIC(EmittedFragments, "Number of emitted assembler fragments");
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// FIXME FIXME FIXME: There are number of places in this file where we convert
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// what is a 64-bit assembler value used for computation into a value in the
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// object file, which may truncate it. We should detect that truncation where
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// invalid and report errors back.
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static void WriteFileData(raw_ostream &OS, const MCSectionData &SD,
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MachObjectWriter &MOW);
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/// isVirtualSection - Check if this is a section which does not actually exist
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/// in the object file.
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static bool isVirtualSection(const MCSection &Section) {
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// FIXME: Lame.
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const MCSectionMachO &SMO = static_cast<const MCSectionMachO&>(Section);
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unsigned Type = SMO.getTypeAndAttributes() & MCSectionMachO::SECTION_TYPE;
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return (Type == MCSectionMachO::S_ZEROFILL);
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}
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class MachObjectWriter {
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// See <mach-o/loader.h>.
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enum {
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Header_Magic32 = 0xFEEDFACE,
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Header_Magic64 = 0xFEEDFACF
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};
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static const unsigned Header32Size = 28;
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static const unsigned Header64Size = 32;
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static const unsigned SegmentLoadCommand32Size = 56;
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static const unsigned Section32Size = 68;
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static const unsigned SymtabLoadCommandSize = 24;
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static const unsigned DysymtabLoadCommandSize = 80;
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static const unsigned Nlist32Size = 12;
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static const unsigned RelocationInfoSize = 8;
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enum HeaderFileType {
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HFT_Object = 0x1
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};
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enum HeaderFlags {
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HF_SubsectionsViaSymbols = 0x2000
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};
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enum LoadCommandType {
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LCT_Segment = 0x1,
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LCT_Symtab = 0x2,
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LCT_Dysymtab = 0xb
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};
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// See <mach-o/nlist.h>.
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enum SymbolTypeType {
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STT_Undefined = 0x00,
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STT_Absolute = 0x02,
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STT_Section = 0x0e
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};
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enum SymbolTypeFlags {
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// If any of these bits are set, then the entry is a stab entry number (see
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// <mach-o/stab.h>. Otherwise the other masks apply.
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STF_StabsEntryMask = 0xe0,
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STF_TypeMask = 0x0e,
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STF_External = 0x01,
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STF_PrivateExtern = 0x10
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};
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/// IndirectSymbolFlags - Flags for encoding special values in the indirect
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/// symbol entry.
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enum IndirectSymbolFlags {
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ISF_Local = 0x80000000,
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ISF_Absolute = 0x40000000
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};
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/// RelocationFlags - Special flags for addresses.
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enum RelocationFlags {
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RF_Scattered = 0x80000000
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};
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enum RelocationInfoType {
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RIT_Vanilla = 0,
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RIT_Pair = 1,
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RIT_Difference = 2,
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RIT_PreboundLazyPointer = 3,
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RIT_LocalDifference = 4
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};
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/// MachSymbolData - Helper struct for containing some precomputed information
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/// on symbols.
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struct MachSymbolData {
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MCSymbolData *SymbolData;
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uint64_t StringIndex;
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uint8_t SectionIndex;
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// Support lexicographic sorting.
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bool operator<(const MachSymbolData &RHS) const {
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const std::string &Name = SymbolData->getSymbol().getName();
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return Name < RHS.SymbolData->getSymbol().getName();
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}
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};
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raw_ostream &OS;
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bool IsLSB;
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public:
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MachObjectWriter(raw_ostream &_OS, bool _IsLSB = true)
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: OS(_OS), IsLSB(_IsLSB) {
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}
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/// @name Helper Methods
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/// @{
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void Write8(uint8_t Value) {
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OS << char(Value);
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}
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void Write16(uint16_t Value) {
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if (IsLSB) {
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Write8(uint8_t(Value >> 0));
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Write8(uint8_t(Value >> 8));
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} else {
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Write8(uint8_t(Value >> 8));
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Write8(uint8_t(Value >> 0));
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}
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}
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void Write32(uint32_t Value) {
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if (IsLSB) {
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Write16(uint16_t(Value >> 0));
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Write16(uint16_t(Value >> 16));
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} else {
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Write16(uint16_t(Value >> 16));
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Write16(uint16_t(Value >> 0));
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}
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}
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void Write64(uint64_t Value) {
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if (IsLSB) {
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Write32(uint32_t(Value >> 0));
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Write32(uint32_t(Value >> 32));
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} else {
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Write32(uint32_t(Value >> 32));
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Write32(uint32_t(Value >> 0));
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}
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}
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void WriteZeros(unsigned N) {
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const char Zeros[16] = { 0 };
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for (unsigned i = 0, e = N / 16; i != e; ++i)
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OS << StringRef(Zeros, 16);
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OS << StringRef(Zeros, N % 16);
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}
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void WriteString(StringRef Str, unsigned ZeroFillSize = 0) {
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OS << Str;
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if (ZeroFillSize)
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WriteZeros(ZeroFillSize - Str.size());
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}
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/// @}
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void WriteHeader32(unsigned NumLoadCommands, unsigned LoadCommandsSize,
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bool SubsectionsViaSymbols) {
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uint32_t Flags = 0;
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if (SubsectionsViaSymbols)
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Flags |= HF_SubsectionsViaSymbols;
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// struct mach_header (28 bytes)
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uint64_t Start = OS.tell();
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(void) Start;
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Write32(Header_Magic32);
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// FIXME: Support cputype.
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Write32(TargetMachOWriterInfo::HDR_CPU_TYPE_I386);
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// FIXME: Support cpusubtype.
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Write32(TargetMachOWriterInfo::HDR_CPU_SUBTYPE_I386_ALL);
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Write32(HFT_Object);
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Write32(NumLoadCommands); // Object files have a single load command, the
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// segment.
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Write32(LoadCommandsSize);
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Write32(Flags);
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assert(OS.tell() - Start == Header32Size);
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}
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/// WriteSegmentLoadCommand32 - Write a 32-bit segment load command.
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///
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/// \arg NumSections - The number of sections in this segment.
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/// \arg SectionDataSize - The total size of the sections.
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void WriteSegmentLoadCommand32(unsigned NumSections,
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uint64_t VMSize,
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uint64_t SectionDataStartOffset,
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uint64_t SectionDataSize) {
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// struct segment_command (56 bytes)
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uint64_t Start = OS.tell();
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(void) Start;
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Write32(LCT_Segment);
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Write32(SegmentLoadCommand32Size + NumSections * Section32Size);
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WriteString("", 16);
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Write32(0); // vmaddr
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Write32(VMSize); // vmsize
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Write32(SectionDataStartOffset); // file offset
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Write32(SectionDataSize); // file size
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Write32(0x7); // maxprot
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Write32(0x7); // initprot
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Write32(NumSections);
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Write32(0); // flags
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assert(OS.tell() - Start == SegmentLoadCommand32Size);
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}
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void WriteSection32(const MCSectionData &SD, uint64_t FileOffset,
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uint64_t RelocationsStart, unsigned NumRelocations) {
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// The offset is unused for virtual sections.
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if (isVirtualSection(SD.getSection())) {
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assert(SD.getFileSize() == 0 && "Invalid file size!");
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FileOffset = 0;
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}
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// struct section (68 bytes)
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uint64_t Start = OS.tell();
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(void) Start;
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// FIXME: cast<> support!
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const MCSectionMachO &Section =
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static_cast<const MCSectionMachO&>(SD.getSection());
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WriteString(Section.getSectionName(), 16);
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WriteString(Section.getSegmentName(), 16);
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Write32(SD.getAddress()); // address
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Write32(SD.getSize()); // size
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Write32(FileOffset);
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assert(isPowerOf2_32(SD.getAlignment()) && "Invalid alignment!");
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Write32(Log2_32(SD.getAlignment()));
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Write32(NumRelocations ? RelocationsStart : 0);
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Write32(NumRelocations);
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Write32(Section.getTypeAndAttributes());
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Write32(0); // reserved1
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Write32(Section.getStubSize()); // reserved2
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assert(OS.tell() - Start == Section32Size);
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}
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void WriteSymtabLoadCommand(uint32_t SymbolOffset, uint32_t NumSymbols,
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uint32_t StringTableOffset,
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uint32_t StringTableSize) {
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// struct symtab_command (24 bytes)
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uint64_t Start = OS.tell();
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(void) Start;
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Write32(LCT_Symtab);
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Write32(SymtabLoadCommandSize);
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Write32(SymbolOffset);
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Write32(NumSymbols);
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Write32(StringTableOffset);
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Write32(StringTableSize);
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assert(OS.tell() - Start == SymtabLoadCommandSize);
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}
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void WriteDysymtabLoadCommand(uint32_t FirstLocalSymbol,
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uint32_t NumLocalSymbols,
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uint32_t FirstExternalSymbol,
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uint32_t NumExternalSymbols,
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uint32_t FirstUndefinedSymbol,
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uint32_t NumUndefinedSymbols,
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uint32_t IndirectSymbolOffset,
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uint32_t NumIndirectSymbols) {
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// struct dysymtab_command (80 bytes)
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uint64_t Start = OS.tell();
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(void) Start;
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Write32(LCT_Dysymtab);
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Write32(DysymtabLoadCommandSize);
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Write32(FirstLocalSymbol);
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Write32(NumLocalSymbols);
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Write32(FirstExternalSymbol);
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Write32(NumExternalSymbols);
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Write32(FirstUndefinedSymbol);
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Write32(NumUndefinedSymbols);
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Write32(0); // tocoff
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Write32(0); // ntoc
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Write32(0); // modtaboff
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Write32(0); // nmodtab
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Write32(0); // extrefsymoff
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Write32(0); // nextrefsyms
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Write32(IndirectSymbolOffset);
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Write32(NumIndirectSymbols);
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Write32(0); // extreloff
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Write32(0); // nextrel
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Write32(0); // locreloff
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Write32(0); // nlocrel
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assert(OS.tell() - Start == DysymtabLoadCommandSize);
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}
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void WriteNlist32(MachSymbolData &MSD) {
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MCSymbolData &Data = *MSD.SymbolData;
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const MCSymbol &Symbol = Data.getSymbol();
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uint8_t Type = 0;
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uint16_t Flags = Data.getFlags();
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uint32_t Address = 0;
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// Set the N_TYPE bits. See <mach-o/nlist.h>.
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//
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// FIXME: Are the prebound or indirect fields possible here?
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if (Symbol.isUndefined())
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Type = STT_Undefined;
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else if (Symbol.isAbsolute())
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Type = STT_Absolute;
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else
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Type = STT_Section;
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// FIXME: Set STAB bits.
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if (Data.isPrivateExtern())
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Type |= STF_PrivateExtern;
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// Set external bit.
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if (Data.isExternal() || Symbol.isUndefined())
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Type |= STF_External;
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// Compute the symbol address.
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if (Symbol.isDefined()) {
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if (Symbol.isAbsolute()) {
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llvm_unreachable("FIXME: Not yet implemented!");
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} else {
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Address = Data.getFragment()->getAddress() + Data.getOffset();
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}
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} else if (Data.isCommon()) {
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// Common symbols are encoded with the size in the address
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// field, and their alignment in the flags.
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Address = Data.getCommonSize();
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// Common alignment is packed into the 'desc' bits.
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if (unsigned Align = Data.getCommonAlignment()) {
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unsigned Log2Size = Log2_32(Align);
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assert((1U << Log2Size) == Align && "Invalid 'common' alignment!");
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if (Log2Size > 15)
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llvm_report_error("invalid 'common' alignment '" +
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Twine(Align) + "'");
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// FIXME: Keep this mask with the SymbolFlags enumeration.
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Flags = (Flags & 0xF0FF) | (Log2Size << 8);
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}
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}
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// struct nlist (12 bytes)
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Write32(MSD.StringIndex);
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Write8(Type);
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Write8(MSD.SectionIndex);
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// The Mach-O streamer uses the lowest 16-bits of the flags for the 'desc'
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// value.
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Write16(Flags);
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Write32(Address);
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}
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struct MachRelocationEntry {
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uint32_t Word0;
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uint32_t Word1;
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};
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void ComputeScatteredRelocationInfo(MCAssembler &Asm,
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MCSectionData::Fixup &Fixup,
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const MCValue &Target,
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DenseMap<const MCSymbol*,MCSymbolData*> &SymbolMap,
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std::vector<MachRelocationEntry> &Relocs) {
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uint32_t Address = Fixup.Fragment->getOffset() + Fixup.Offset;
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unsigned IsPCRel = 0;
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unsigned Type = RIT_Vanilla;
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// See <reloc.h>.
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const MCSymbol *A = Target.getSymA();
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MCSymbolData *SD = SymbolMap.lookup(A);
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uint32_t Value = SD->getFragment()->getAddress() + SD->getOffset();
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uint32_t Value2 = 0;
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if (const MCSymbol *B = Target.getSymB()) {
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Type = RIT_LocalDifference;
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MCSymbolData *SD = SymbolMap.lookup(B);
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Value2 = SD->getFragment()->getAddress() + SD->getOffset();
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}
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unsigned Log2Size = Log2_32(Fixup.Size);
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assert((1U << Log2Size) == Fixup.Size && "Invalid fixup size!");
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// The value which goes in the fixup is current value of the expression.
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Fixup.FixedValue = Value - Value2 + Target.getConstant();
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MachRelocationEntry MRE;
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MRE.Word0 = ((Address << 0) |
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(Type << 24) |
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(Log2Size << 28) |
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(IsPCRel << 30) |
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RF_Scattered);
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MRE.Word1 = Value;
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Relocs.push_back(MRE);
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if (Type == RIT_LocalDifference) {
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Type = RIT_Pair;
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MachRelocationEntry MRE;
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MRE.Word0 = ((0 << 0) |
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(Type << 24) |
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(Log2Size << 28) |
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(0 << 30) |
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RF_Scattered);
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MRE.Word1 = Value2;
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Relocs.push_back(MRE);
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}
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}
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void ComputeRelocationInfo(MCAssembler &Asm,
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MCSectionData::Fixup &Fixup,
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DenseMap<const MCSymbol*,MCSymbolData*> &SymbolMap,
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std::vector<MachRelocationEntry> &Relocs) {
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MCValue Target;
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if (!Fixup.Value->EvaluateAsRelocatable(Target))
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llvm_report_error("expected relocatable expression");
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// If this is a difference or a local symbol plus an offset, then we need a
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// scattered relocation entry.
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if (Target.getSymB() ||
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(Target.getSymA() && !Target.getSymA()->isUndefined() &&
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Target.getConstant()))
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return ComputeScatteredRelocationInfo(Asm, Fixup, Target,
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SymbolMap, Relocs);
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// See <reloc.h>.
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uint32_t Address = Fixup.Fragment->getOffset() + Fixup.Offset;
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uint32_t Value = 0;
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unsigned Index = 0;
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unsigned IsPCRel = 0;
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unsigned IsExtern = 0;
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unsigned Type = 0;
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if (Target.isAbsolute()) { // constant
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// SymbolNum of 0 indicates the absolute section.
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Type = RIT_Vanilla;
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Value = 0;
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llvm_unreachable("FIXME: Not yet implemented!");
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} else {
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const MCSymbol *Symbol = Target.getSymA();
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MCSymbolData *SD = SymbolMap.lookup(Symbol);
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if (Symbol->isUndefined()) {
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IsExtern = 1;
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Index = SD->getIndex();
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Value = 0;
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} else {
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// The index is the section ordinal.
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//
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// FIXME: O(N)
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Index = 1;
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for (MCAssembler::iterator it = Asm.begin(),
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ie = Asm.end(); it != ie; ++it, ++Index)
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if (&*it == SD->getFragment()->getParent())
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break;
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Value = SD->getFragment()->getAddress() + SD->getOffset();
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}
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Type = RIT_Vanilla;
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}
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// The value which goes in the fixup is current value of the expression.
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Fixup.FixedValue = Value + Target.getConstant();
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unsigned Log2Size = Log2_32(Fixup.Size);
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assert((1U << Log2Size) == Fixup.Size && "Invalid fixup size!");
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// struct relocation_info (8 bytes)
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MachRelocationEntry MRE;
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MRE.Word0 = Address;
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MRE.Word1 = ((Index << 0) |
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(IsPCRel << 24) |
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(Log2Size << 25) |
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(IsExtern << 27) |
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(Type << 28));
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Relocs.push_back(MRE);
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}
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|
|
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.
|
|
//
|
|
// FIXME: Check to see if this varies per arch.
|
|
while (StringTable.size() % 4)
|
|
StringTable += '\x00';
|
|
}
|
|
|
|
void WriteObject(MCAssembler &Asm) {
|
|
unsigned NumSections = Asm.size();
|
|
|
|
// 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;
|
|
}
|
|
|
|
// 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());
|
|
}
|
|
|
|
// The section data is passed 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...
|
|
WriteHeader32(NumLoadCommands, LoadCommandsSize,
|
|
Asm.getSubsectionsViaSymbols());
|
|
WriteSegmentLoadCommand32(NumSections, VMSize,
|
|
SectionDataStart, SectionDataSize);
|
|
|
|
// ... and then the section headers.
|
|
//
|
|
// We also compute the section relocations while we do this. Note that
|
|
// compute relocation info will also update the fixup to have the correct
|
|
// value; this will be 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 (unsigned i = 0, e = SD.fixup_size(); i != e; ++i)
|
|
ComputeRelocationInfo(Asm, SD.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);
|
|
}
|
|
|
|
// 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();
|
|
}
|
|
}
|
|
};
|
|
|
|
/* *** */
|
|
|
|
MCFragment::MCFragment() : Kind(FragmentType(~0)) {
|
|
}
|
|
|
|
MCFragment::MCFragment(FragmentType _Kind, MCSectionData *_Parent)
|
|
: Kind(_Kind),
|
|
Parent(_Parent),
|
|
FileSize(~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) {}
|
|
|
|
MCSectionData::MCSectionData(const MCSection &_Section, MCAssembler *A)
|
|
: Section(&_Section),
|
|
Alignment(1),
|
|
Address(~UINT64_C(0)),
|
|
Size(~UINT64_C(0)),
|
|
FileSize(~UINT64_C(0)),
|
|
LastFixupLookup(~0)
|
|
{
|
|
if (A)
|
|
A->getSectionList().push_back(this);
|
|
}
|
|
|
|
const MCSectionData::Fixup *
|
|
MCSectionData::LookupFixup(const MCFragment *Fragment, uint64_t Offset) const {
|
|
// Use a one level cache to turn the common case of accessing the fixups in
|
|
// order into O(1) instead of O(N).
|
|
unsigned i = LastFixupLookup, Count = Fixups.size(), End = Fixups.size();
|
|
if (i >= End)
|
|
i = 0;
|
|
while (Count--) {
|
|
const Fixup &F = Fixups[i];
|
|
if (F.Fragment == Fragment && F.Offset == Offset) {
|
|
LastFixupLookup = i;
|
|
return &F;
|
|
}
|
|
|
|
++i;
|
|
if (i == End)
|
|
i = 0;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
/* *** */
|
|
|
|
MCSymbolData::MCSymbolData() : Symbol(0) {}
|
|
|
|
MCSymbolData::MCSymbolData(const MCSymbol &_Symbol, MCFragment *_Fragment,
|
|
uint64_t _Offset, MCAssembler *A)
|
|
: Symbol(&_Symbol), Fragment(_Fragment), Offset(_Offset),
|
|
IsExternal(false), IsPrivateExtern(false),
|
|
CommonSize(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() {
|
|
}
|
|
|
|
void MCAssembler::LayoutSection(MCSectionData &SD) {
|
|
uint64_t Address = SD.getAddress();
|
|
|
|
for (MCSectionData::iterator it = SD.begin(), ie = SD.end(); it != ie; ++it) {
|
|
MCFragment &F = *it;
|
|
|
|
F.setOffset(Address - SD.getAddress());
|
|
|
|
// Evaluate fragment size.
|
|
switch (F.getKind()) {
|
|
case MCFragment::FT_Align: {
|
|
MCAlignFragment &AF = cast<MCAlignFragment>(F);
|
|
|
|
uint64_t Size = OffsetToAlignment(Address, AF.getAlignment());
|
|
if (Size > AF.getMaxBytesToEmit())
|
|
AF.setFileSize(0);
|
|
else
|
|
AF.setFileSize(Size);
|
|
break;
|
|
}
|
|
|
|
case MCFragment::FT_Data:
|
|
F.setFileSize(F.getMaxFileSize());
|
|
break;
|
|
|
|
case MCFragment::FT_Fill: {
|
|
MCFillFragment &FF = cast<MCFillFragment>(F);
|
|
|
|
F.setFileSize(F.getMaxFileSize());
|
|
|
|
MCValue Target;
|
|
if (!FF.getValue().EvaluateAsRelocatable(Target))
|
|
llvm_report_error("expected relocatable expression");
|
|
|
|
// If the fill value is constant, thats it.
|
|
if (Target.isAbsolute())
|
|
break;
|
|
|
|
// Otherwise, add fixups for the values.
|
|
for (uint64_t i = 0, e = FF.getCount(); i != e; ++i) {
|
|
MCSectionData::Fixup Fix(F, i * FF.getValueSize(),
|
|
FF.getValue(),FF.getValueSize());
|
|
SD.getFixups().push_back(Fix);
|
|
}
|
|
break;
|
|
}
|
|
|
|
case MCFragment::FT_Org: {
|
|
MCOrgFragment &OF = cast<MCOrgFragment>(F);
|
|
|
|
MCValue Target;
|
|
if (!OF.getOffset().EvaluateAsRelocatable(Target))
|
|
llvm_report_error("expected relocatable expression");
|
|
|
|
if (!Target.isAbsolute())
|
|
llvm_unreachable("FIXME: Not yet implemented!");
|
|
uint64_t OrgOffset = Target.getConstant();
|
|
uint64_t Offset = Address - SD.getAddress();
|
|
|
|
// FIXME: We need a way to communicate this error.
|
|
if (OrgOffset < Offset)
|
|
llvm_report_error("invalid .org offset '" + Twine(OrgOffset) +
|
|
"' (at offset '" + Twine(Offset) + "'");
|
|
|
|
F.setFileSize(OrgOffset - Offset);
|
|
break;
|
|
}
|
|
|
|
case MCFragment::FT_ZeroFill: {
|
|
MCZeroFillFragment &ZFF = cast<MCZeroFillFragment>(F);
|
|
|
|
// Align the fragment offset; it is safe to adjust the offset freely since
|
|
// this is only in virtual sections.
|
|
uint64_t Aligned = RoundUpToAlignment(Address, ZFF.getAlignment());
|
|
F.setOffset(Aligned - SD.getAddress());
|
|
|
|
// FIXME: This is misnamed.
|
|
F.setFileSize(ZFF.getSize());
|
|
break;
|
|
}
|
|
}
|
|
|
|
Address += F.getFileSize();
|
|
}
|
|
|
|
// Set the section sizes.
|
|
SD.setSize(Address - SD.getAddress());
|
|
if (isVirtualSection(SD.getSection()))
|
|
SD.setFileSize(0);
|
|
else
|
|
SD.setFileSize(Address - SD.getAddress());
|
|
}
|
|
|
|
/// 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;
|
|
|
|
++EmittedFragments;
|
|
|
|
// FIXME: Embed in fragments instead?
|
|
switch (F.getKind()) {
|
|
case MCFragment::FT_Align: {
|
|
MCAlignFragment &AF = cast<MCAlignFragment>(F);
|
|
uint64_t Count = AF.getFileSize() / 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 '" +
|
|
Twine(AF.getValueSize()) +
|
|
"' is not a divisor of padding size '" +
|
|
Twine(AF.getFileSize()) + "'");
|
|
|
|
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;
|
|
}
|
|
}
|
|
break;
|
|
}
|
|
|
|
case MCFragment::FT_Data:
|
|
OS << cast<MCDataFragment>(F).getContents().str();
|
|
break;
|
|
|
|
case MCFragment::FT_Fill: {
|
|
MCFillFragment &FF = cast<MCFillFragment>(F);
|
|
|
|
int64_t Value = 0;
|
|
|
|
MCValue Target;
|
|
if (!FF.getValue().EvaluateAsRelocatable(Target))
|
|
llvm_report_error("expected relocatable expression");
|
|
|
|
if (Target.isAbsolute())
|
|
Value = Target.getConstant();
|
|
for (uint64_t i = 0, e = FF.getCount(); i != e; ++i) {
|
|
if (!Target.isAbsolute()) {
|
|
// Find the fixup.
|
|
//
|
|
// FIXME: Find a better way to write in the fixes.
|
|
const MCSectionData::Fixup *Fixup =
|
|
F.getParent()->LookupFixup(&F, i * FF.getValueSize());
|
|
assert(Fixup && "Missing fixup for fill value!");
|
|
Value = Fixup->FixedValue;
|
|
}
|
|
|
|
switch (FF.getValueSize()) {
|
|
default:
|
|
assert(0 && "Invalid size!");
|
|
case 1: MOW.Write8 (uint8_t (Value)); break;
|
|
case 2: MOW.Write16(uint16_t(Value)); break;
|
|
case 4: MOW.Write32(uint32_t(Value)); break;
|
|
case 8: MOW.Write64(uint64_t(Value)); break;
|
|
}
|
|
}
|
|
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()));
|
|
|
|
break;
|
|
}
|
|
|
|
case MCFragment::FT_ZeroFill: {
|
|
assert(0 && "Invalid zero fill fragment in concrete section!");
|
|
break;
|
|
}
|
|
}
|
|
|
|
assert(OS.tell() - Start == F.getFileSize());
|
|
}
|
|
|
|
/// WriteFileData - Write the \arg SD data to the output file.
|
|
static void WriteFileData(raw_ostream &OS, const MCSectionData &SD,
|
|
MachObjectWriter &MOW) {
|
|
// Ignore virtual sections.
|
|
if (isVirtualSection(SD.getSection())) {
|
|
assert(SD.getFileSize() == 0);
|
|
return;
|
|
}
|
|
|
|
uint64_t Start = OS.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());
|
|
|
|
assert(OS.tell() - Start == SD.getFileSize());
|
|
}
|
|
|
|
void MCAssembler::Finish() {
|
|
// 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;
|
|
}
|
|
|
|
// Layout the section fragments and its size.
|
|
SD.setAddress(Address);
|
|
LayoutSection(SD);
|
|
Address += SD.getFileSize();
|
|
|
|
Prev = &SD;
|
|
}
|
|
|
|
// Layout the virtual sections.
|
|
for (iterator it = begin(), ie = end(); it != ie; ++it) {
|
|
MCSectionData &SD = *it;
|
|
|
|
if (!isVirtualSection(SD.getSection()))
|
|
continue;
|
|
|
|
SD.setAddress(Address);
|
|
LayoutSection(SD);
|
|
Address += SD.getSize();
|
|
}
|
|
|
|
// Write the object file.
|
|
MachObjectWriter MOW(OS);
|
|
MOW.WriteObject(*this);
|
|
|
|
OS.flush();
|
|
}
|