X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FMC%2FMachObjectWriter.cpp;h=a94b2140227f579efe791c86f12f59820573413d;hb=b21d9aebba7e45ddcbce61dd501000049cefb335;hp=6e720115dd1648687a704e96797903c5b2bfbfdd;hpb=f68a26b5d8e06a85edba97702884a74673b60807;p=oota-llvm.git diff --git a/lib/MC/MachObjectWriter.cpp b/lib/MC/MachObjectWriter.cpp index 6e720115dd1..a94b2140227 100644 --- a/lib/MC/MachObjectWriter.cpp +++ b/lib/MC/MachObjectWriter.cpp @@ -8,19 +8,20 @@ //===----------------------------------------------------------------------===// #include "llvm/MC/MCMachObjectWriter.h" -#include "llvm/ADT/OwningPtr.h" #include "llvm/ADT/StringMap.h" #include "llvm/ADT/Twine.h" #include "llvm/MC/MCAssembler.h" #include "llvm/MC/MCAsmBackend.h" #include "llvm/MC/MCAsmLayout.h" #include "llvm/MC/MCExpr.h" +#include "llvm/MC/MCFixupKindInfo.h" #include "llvm/MC/MCObjectWriter.h" #include "llvm/MC/MCSectionMachO.h" #include "llvm/MC/MCSymbol.h" #include "llvm/MC/MCMachOSymbolFlags.h" #include "llvm/MC/MCValue.h" #include "llvm/Object/MachOFormat.h" +#include "llvm/Support/Debug.h" #include "llvm/Support/ErrorHandling.h" #include @@ -67,6 +68,11 @@ uint64_t MachObjectWriter::getSymbolAddress(const MCSymbolData* SD, // If this is a variable, then recursively evaluate now. if (S.isVariable()) { + if (const MCConstantExpr *C = + dyn_cast(S.getVariableValue())) + return C->getValue(); + + MCValue Target; if (!S.getVariableValue()->EvaluateAsRelocatable(Target, Layout)) report_fatal_error("unable to evaluate offset for variable '" + @@ -139,8 +145,8 @@ void MachObjectWriter::WriteHeader(unsigned NumLoadCommands, /// WriteSegmentLoadCommand - Write a segment load command. /// -/// \arg NumSections - The number of sections in this segment. -/// \arg SectionDataSize - The total size of the sections. +/// \param NumSections The number of sections in this segment. +/// \param SectionDataSize The total size of the sections. void MachObjectWriter::WriteSegmentLoadCommand(unsigned NumSections, uint64_t VMSize, uint64_t SectionDataStartOffset, @@ -314,11 +320,7 @@ void MachObjectWriter::WriteNlist(MachSymbolData &MSD, // Compute the symbol address. if (Symbol.isDefined()) { - if (Symbol.isAbsolute()) { - Address = cast(Symbol.getVariableValue())->getValue(); - } else { - Address = getSymbolAddress(&Data, Layout); - } + Address = getSymbolAddress(&Data, Layout); } else if (Data.isCommon()) { // Common symbols are encoded with the size in the address // field, and their alignment in the flags. @@ -351,6 +353,21 @@ void MachObjectWriter::WriteNlist(MachSymbolData &MSD, Write32(Address); } +void MachObjectWriter::WriteLinkeditLoadCommand(uint32_t Type, + uint32_t DataOffset, + uint32_t DataSize) { + uint64_t Start = OS.tell(); + (void) Start; + + Write32(Type); + Write32(macho::LinkeditLoadCommandSize); + Write32(DataOffset); + Write32(DataSize); + + assert(OS.tell() - Start == macho::LinkeditLoadCommandSize); +} + + void MachObjectWriter::RecordRelocation(const MCAssembler &Asm, const MCAsmLayout &Layout, const MCFragment *Fragment, @@ -380,8 +397,7 @@ void MachObjectWriter::BindIndirectSymbols(MCAssembler &Asm) { continue; // Initialize the section indirect symbol base, if necessary. - if (!IndirectSymBase.count(it->SectionData)) - IndirectSymBase[it->SectionData] = IndirectIndex; + IndirectSymBase.insert(std::make_pair(it->SectionData, IndirectIndex)); Asm.getOrCreateSymbolData(*it->Symbol); } @@ -398,8 +414,7 @@ void MachObjectWriter::BindIndirectSymbols(MCAssembler &Asm) { continue; // Initialize the section indirect symbol base, if necessary. - if (!IndirectSymBase.count(it->SectionData)) - IndirectSymBase[it->SectionData] = IndirectIndex; + IndirectSymBase.insert(std::make_pair(it->SectionData, IndirectIndex)); // Set the symbol type to undefined lazy, but only on construction. // @@ -543,6 +558,26 @@ void MachObjectWriter::computeSectionAddresses(const MCAssembler &Asm, } } +void MachObjectWriter::markAbsoluteVariableSymbols(MCAssembler &Asm, + const MCAsmLayout &Layout) { + for (MCAssembler::symbol_iterator i = Asm.symbol_begin(), + e = Asm.symbol_end(); + i != e; ++i) { + MCSymbolData &SD = *i; + if (!SD.getSymbol().isVariable()) + continue; + + // Is the variable is a symbol difference (SA - SB + C) expression, + // and neither symbol is external, mark the variable as absolute. + const MCExpr *Expr = SD.getSymbol().getVariableValue(); + MCValue Value; + if (Expr->EvaluateAsRelocatable(Value, Layout)) { + if (Value.getSymA() && Value.getSymB()) + const_cast(&SD.getSymbol())->setAbsolute(); + } + } +} + void MachObjectWriter::ExecutePostLayoutBinding(MCAssembler &Asm, const MCAsmLayout &Layout) { computeSectionAddresses(Asm, Layout); @@ -550,6 +585,10 @@ void MachObjectWriter::ExecutePostLayoutBinding(MCAssembler &Asm, // Create symbol data for any indirect symbols. BindIndirectSymbols(Asm); + // Mark symbol difference expressions in variables (from .set or = directives) + // as absolute. + markAbsoluteVariableSymbols(Asm, Layout); + // Compute symbol table information and bind symbol indices. ComputeSymbolTable(Asm, StringTable, LocalSymbolData, ExternalSymbolData, UndefinedSymbolData); @@ -584,9 +623,16 @@ IsSymbolRefDifferenceFullyResolvedImpl(const MCAssembler &Asm, // 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 considering symbol differences fully resolved. + // + // If the file isn't using sub-sections-via-symbols, we can make the + // same assumptions about any symbol that we normally make about + // assembler locals. if (!Asm.getBackend().hasReliableSymbolDifference()) { - if (!SA.isTemporary() || !SA.isInSection() || &SecA != &SecB) + if (!SA.isInSection() || &SecA != &SecB || + (!SA.isTemporary() && + FB.getAtom() != Asm.getSymbolData(SA).getFragment()->getAtom() && + Asm.getSubsectionsViaSymbols())) return false; return true; } @@ -647,6 +693,13 @@ void MachObjectWriter::WriteObject(MCAssembler &Asm, macho::DysymtabLoadCommandSize); } + // Add the data-in-code load command size, if used. + unsigned NumDataRegions = Asm.getDataRegions().size(); + if (NumDataRegions) { + ++NumLoadCommands; + LoadCommandsSize += macho::LinkeditLoadCommandSize; + } + // Compute the total size of the section data, as well as its file size and vm // size. uint64_t SectionDataStart = (is64Bit() ? macho::Header64Size : @@ -694,6 +747,15 @@ void MachObjectWriter::WriteObject(MCAssembler &Asm, RelocTableEnd += NumRelocs * macho::RelocationInfoSize; } + // Write the data-in-code load command, if used. + uint64_t DataInCodeTableEnd = RelocTableEnd + NumDataRegions * 8; + if (NumDataRegions) { + uint64_t DataRegionsOffset = RelocTableEnd; + uint64_t DataRegionsSize = NumDataRegions * 8; + WriteLinkeditLoadCommand(macho::LCT_DataInCode, DataRegionsOffset, + DataRegionsSize); + } + // Write the symbol table load command, if used. if (NumSymbols) { unsigned FirstLocalSymbol = 0; @@ -710,10 +772,10 @@ void MachObjectWriter::WriteObject(MCAssembler &Asm, // If used, the indirect symbols are written after the section data. if (NumIndirectSymbols) - IndirectSymbolOffset = RelocTableEnd; + IndirectSymbolOffset = DataInCodeTableEnd; // The symbol table is written after the indirect symbol data. - uint64_t SymbolTableOffset = RelocTableEnd + IndirectSymbolSize; + uint64_t SymbolTableOffset = DataInCodeTableEnd + IndirectSymbolSize; // The string table is written after symbol table. uint64_t StringTableOffset = @@ -753,6 +815,27 @@ void MachObjectWriter::WriteObject(MCAssembler &Asm, } } + // Write out the data-in-code region payload, if there is one. + for (MCAssembler::const_data_region_iterator + it = Asm.data_region_begin(), ie = Asm.data_region_end(); + it != ie; ++it) { + const DataRegionData *Data = &(*it); + uint64_t Start = + getSymbolAddress(&Layout.getAssembler().getSymbolData(*Data->Start), + Layout); + uint64_t End = + getSymbolAddress(&Layout.getAssembler().getSymbolData(*Data->End), + Layout); + DEBUG(dbgs() << "data in code region-- kind: " << Data->Kind + << " start: " << Start << "(" << Data->Start->getName() << ")" + << " end: " << End << "(" << Data->End->getName() << ")" + << " size: " << End - Start + << "\n"); + Write32(Start); + Write16(End - Start); + Write16(Data->Kind); + } + // Write the symbol table data, if used. if (NumSymbols) { // Write the indirect symbol entries.