#define DEBUG_TYPE "assembler"
#include "llvm/MC/MCAssembler.h"
+#include "llvm/MC/MCExpr.h"
#include "llvm/MC/MCSectionMachO.h"
+#include "llvm/MC/MCSymbol.h"
+#include "llvm/MC/MCValue.h"
#include "llvm/Target/TargetMachOWriterInfo.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/SmallString.h"
STATISTIC(EmittedFragments, "Number of emitted assembler fragments");
+// 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);
+/// isVirtualSection - Check if this is a section which does not actually exist
+/// in the object file.
+static bool isVirtualSection(const MCSection &Section) {
+ // FIXME: Lame.
+ const MCSectionMachO &SMO = static_cast<const MCSectionMachO&>(Section);
+ unsigned Type = SMO.getTypeAndAttributes() & MCSectionMachO::SECTION_TYPE;
+ return (Type == MCSectionMachO::S_ZEROFILL);
+}
+
class MachObjectWriter {
// See <mach-o/loader.h>.
enum {
Header_Magic32 = 0xFEEDFACE,
Header_Magic64 = 0xFEEDFACF
};
-
+
static const unsigned Header32Size = 28;
static const unsigned Header64Size = 32;
static const unsigned SegmentLoadCommand32Size = 56;
bool IsLSB;
public:
- MachObjectWriter(raw_ostream &_OS, bool _IsLSB = true)
+ MachObjectWriter(raw_ostream &_OS, bool _IsLSB = true)
: OS(_OS), IsLSB(_IsLSB) {
}
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(const StringRef &Str, unsigned ZeroFillSize = 0) {
+ void WriteString(StringRef Str, unsigned ZeroFillSize = 0) {
OS << Str;
if (ZeroFillSize)
WriteZeros(ZeroFillSize - Str.size());
}
/// @}
-
+
void WriteHeader32(unsigned NumLoadCommands, unsigned LoadCommandsSize,
bool SubsectionsViaSymbols) {
uint32_t Flags = 0;
void WriteSection32(const MCSectionData &SD, uint64_t FileOffset,
uint64_t RelocationsStart, unsigned NumRelocations) {
+ // The offset is unused for virtual sections.
+ if (isVirtualSection(SD.getSection())) {
+ assert(SD.getFileSize() == 0 && "Invalid file size!");
+ FileOffset = 0;
+ }
+
// struct section (68 bytes)
uint64_t Start = OS.tell();
void WriteNlist32(MachSymbolData &MSD) {
MCSymbolData &Data = *MSD.SymbolData;
- MCSymbol &Symbol = Data.getSymbol();
+ 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>.
//
if (Data.isExternal() || Symbol.isUndefined())
Type |= STF_External;
- // 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(Data.getFlags() & 0xFFFF);
-
- // Write the symbol address.
- uint32_t Address = 0;
+ // Compute the symbol address.
if (Symbol.isDefined()) {
if (Symbol.isAbsolute()) {
llvm_unreachable("FIXME: Not yet implemented!");
} else {
Address = Data.getFragment()->getAddress() + Data.getOffset();
}
+ } else if (Data.isCommon()) {
+ // Common symbols are encoded with the size in the address
+ // field, and their alignment in the flags.
+ Address = Data.getCommonSize();
+
+ // Common alignment is packed into the 'desc' bits.
+ if (unsigned Align = Data.getCommonAlignment()) {
+ unsigned Log2Size = Log2_32(Align);
+ assert((1U << Log2Size) == Align && "Invalid 'common' alignment!");
+ if (Log2Size > 15)
+ llvm_report_error("invalid 'common' alignment '" +
+ Twine(Align) + "'");
+ // FIXME: Keep this mask with the SymbolFlags enumeration.
+ Flags = (Flags & 0xF0FF) | (Log2Size << 8);
+ }
}
+
+ // 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);
Write32(Address);
}
};
void ComputeScatteredRelocationInfo(MCAssembler &Asm,
MCSectionData::Fixup &Fixup,
+ const MCValue &Target,
DenseMap<const MCSymbol*,MCSymbolData*> &SymbolMap,
std::vector<MachRelocationEntry> &Relocs) {
uint32_t Address = Fixup.Fragment->getOffset() + Fixup.Offset;
unsigned Type = RIT_Vanilla;
// See <reloc.h>.
-
- const MCSymbol *A = Fixup.Value.getSymA();
+ const MCSymbol *A = Target.getSymA();
MCSymbolData *SD = SymbolMap.lookup(A);
uint32_t Value = SD->getFragment()->getAddress() + SD->getOffset();
uint32_t Value2 = 0;
- if (const MCSymbol *B = Fixup.Value.getSymB()) {
+ if (const MCSymbol *B = Target.getSymB()) {
Type = RIT_LocalDifference;
MCSymbolData *SD = SymbolMap.lookup(B);
assert((1U << Log2Size) == Fixup.Size && "Invalid fixup size!");
// The value which goes in the fixup is current value of the expression.
- Fixup.FixedValue = Value - Value2 + Fixup.Value.getConstant();
+ Fixup.FixedValue = Value - Value2 + Target.getConstant();
MachRelocationEntry MRE;
MRE.Word0 = ((Address << 0) |
MCSectionData::Fixup &Fixup,
DenseMap<const MCSymbol*,MCSymbolData*> &SymbolMap,
std::vector<MachRelocationEntry> &Relocs) {
- // If this is a local symbol plus an offset or a difference, then we need a
+ MCValue Target;
+ if (!Fixup.Value->EvaluateAsRelocatable(Target))
+ llvm_report_error("expected relocatable expression");
+
+ // If this is a difference or a local symbol plus an offset, then we need a
// scattered relocation entry.
- if (Fixup.Value.getSymB()) // a - b
- return ComputeScatteredRelocationInfo(Asm, Fixup, SymbolMap, Relocs);
- if (Fixup.Value.getSymA() && Fixup.Value.getConstant())
- if (!Fixup.Value.getSymA()->isUndefined())
- return ComputeScatteredRelocationInfo(Asm, Fixup, SymbolMap, Relocs);
-
+ if (Target.getSymB() ||
+ (Target.getSymA() && !Target.getSymA()->isUndefined() &&
+ Target.getConstant()))
+ return ComputeScatteredRelocationInfo(Asm, Fixup, Target,
+ SymbolMap, Relocs);
+
// See <reloc.h>.
uint32_t Address = Fixup.Fragment->getOffset() + Fixup.Offset;
uint32_t Value = 0;
unsigned IsExtern = 0;
unsigned Type = 0;
- if (Fixup.Value.isAbsolute()) { // constant
+ if (Target.isAbsolute()) { // constant
// SymbolNum of 0 indicates the absolute section.
Type = RIT_Vanilla;
Value = 0;
llvm_unreachable("FIXME: Not yet implemented!");
} else {
- const MCSymbol *Symbol = Fixup.Value.getSymA();
+ const MCSymbol *Symbol = Target.getSymA();
MCSymbolData *SD = SymbolMap.lookup(Symbol);
-
+
if (Symbol->isUndefined()) {
IsExtern = 1;
Index = SD->getIndex();
}
// The value which goes in the fixup is current value of the expression.
- Fixup.FixedValue = Value + Fixup.Value.getConstant();
+ Fixup.FixedValue = Value + Target.getConstant();
unsigned Log2Size = Log2_32(Fixup.Size);
assert((1U << Log2Size) == Fixup.Size && "Invalid fixup size!");
(Type << 28));
Relocs.push_back(MRE);
}
-
+
void BindIndirectSymbols(MCAssembler &Asm,
DenseMap<const MCSymbol*,MCSymbolData*> &SymbolMap) {
// This is the point where 'as' creates actual symbols for indirect symbols
// files.
for (MCAssembler::symbol_iterator it = Asm.symbol_begin(),
ie = Asm.symbol_end(); it != ie; ++it) {
- MCSymbol &Symbol = it->getSymbol();
+ const MCSymbol &Symbol = it->getSymbol();
// Ignore assembler temporaries.
if (it->getSymbol().isTemporary())
// Now add the data for local symbols.
for (MCAssembler::symbol_iterator it = Asm.symbol_begin(),
ie = Asm.symbol_end(); it != ie; ++it) {
- MCSymbol &Symbol = it->getSymbol();
+ const MCSymbol &Symbol = it->getSymbol();
// Ignore assembler temporaries.
if (it->getSymbol().isTemporary())
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;
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,
+ SectionDataFileSize = std::max(SectionDataFileSize,
SD.getAddress() + SD.getFileSize());
}
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
WriteSection32(SD, SectionStart, RelocTableEnd, NumRelocs);
RelocTableEnd += NumRelocs * RelocationInfoSize;
}
-
+
// Write the symbol table load command, if used.
if (NumSymbols) {
unsigned FirstLocalSymbol = 0;
return 0;
}
-
+
/* *** */
-MCSymbolData::MCSymbolData() : Symbol(*(MCSymbol*)0) {}
+MCSymbolData::MCSymbolData() : Symbol(0) {}
-MCSymbolData::MCSymbolData(MCSymbol &_Symbol, MCFragment *_Fragment,
+MCSymbolData::MCSymbolData(const MCSymbol &_Symbol, MCFragment *_Fragment,
uint64_t _Offset, MCAssembler *A)
- : Symbol(_Symbol), Fragment(_Fragment), Offset(_Offset),
- IsExternal(false), IsPrivateExtern(false), Flags(0), Index(0)
+ : 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(raw_ostream &_OS)
- : OS(_OS),
- SubsectionsViaSymbols(false)
+MCAssembler::MCAssembler(MCContext &_Context, raw_ostream &_OS)
+ : Context(_Context), OS(_OS), SubsectionsViaSymbols(false)
{
}
switch (F.getKind()) {
case MCFragment::FT_Align: {
MCAlignFragment &AF = cast<MCAlignFragment>(F);
-
- uint64_t Size = RoundUpToAlignment(Address, AF.getAlignment()) - Address;
+
+ uint64_t Size = OffsetToAlignment(Address, AF.getAlignment());
if (Size > AF.getMaxBytesToEmit())
AF.setFileSize(0);
else
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 (FF.getValue().isAbsolute())
+ if (Target.isAbsolute())
break;
// Otherwise, add fixups for the values.
case MCFragment::FT_Org: {
MCOrgFragment &OF = cast<MCOrgFragment>(F);
- if (!OF.getOffset().isAbsolute())
+ 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 = OF.getOffset().getConstant();
+ 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) +
+ 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());
- SD.setFileSize(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.
MachObjectWriter &MOW) {
uint64_t Start = OS.tell();
(void) Start;
-
+
++EmittedFragments;
// FIXME: Embed in fragments instead?
// 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()) +
+ llvm_report_error("undefined .align directive, value size '" +
+ Twine(AF.getValueSize()) +
"' is not a divisor of padding size '" +
Twine(AF.getFileSize()) + "'");
MCFillFragment &FF = cast<MCFillFragment>(F);
int64_t Value = 0;
- if (FF.getValue().isAbsolute())
- Value = FF.getValue().getConstant();
+
+ 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 (!FF.getValue().isAbsolute()) {
+ if (!Target.isAbsolute()) {
// Find the fixup.
//
// FIXME: Find a better way to write in the fixes.
}
break;
}
-
+
case MCFragment::FT_Org: {
MCOrgFragment &OF = cast<MCOrgFragment>(F);
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);
}
void MCAssembler::Finish() {
- // Layout the sections and fragments.
+ // 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())) {
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);
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