It's not necessary to do rounding for alloca operations when the requested
alignment is equal to the stack alignment.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@40004 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/MachOWriter.cpp b/lib/CodeGen/MachOWriter.cpp
new file mode 100644
index 0000000..36060e1
--- /dev/null
+++ b/lib/CodeGen/MachOWriter.cpp
@@ -0,0 +1,945 @@
+//===-- MachOWriter.cpp - Target-independent Mach-O Writer code -----------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file was developed by Nate Begeman and is distributed under the
+// University of Illinois Open Source License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements the target-independent Mach-O writer. This file writes
+// out the Mach-O file in the following order:
+//
+// #1 FatHeader (universal-only)
+// #2 FatArch (universal-only, 1 per universal arch)
+// Per arch:
+// #3 Header
+// #4 Load Commands
+// #5 Sections
+// #6 Relocations
+// #7 Symbols
+// #8 Strings
+//
+//===----------------------------------------------------------------------===//
+
+#include "MachOWriter.h"
+#include "llvm/Constants.h"
+#include "llvm/DerivedTypes.h"
+#include "llvm/Module.h"
+#include "llvm/PassManager.h"
+#include "llvm/CodeGen/FileWriters.h"
+#include "llvm/CodeGen/MachineCodeEmitter.h"
+#include "llvm/CodeGen/MachineConstantPool.h"
+#include "llvm/CodeGen/MachineJumpTableInfo.h"
+#include "llvm/Target/TargetAsmInfo.h"
+#include "llvm/Target/TargetJITInfo.h"
+#include "llvm/Support/Mangler.h"
+#include "llvm/Support/MathExtras.h"
+#include "llvm/Support/OutputBuffer.h"
+#include "llvm/Support/Streams.h"
+#include <algorithm>
+using namespace llvm;
+
+/// AddMachOWriter - Concrete function to add the Mach-O writer to the function
+/// pass manager.
+MachineCodeEmitter *llvm::AddMachOWriter(FunctionPassManager &FPM,
+ std::ostream &O,
+ TargetMachine &TM) {
+ MachOWriter *MOW = new MachOWriter(O, TM);
+ FPM.add(MOW);
+ return &MOW->getMachineCodeEmitter();
+}
+
+//===----------------------------------------------------------------------===//
+// MachOCodeEmitter Implementation
+//===----------------------------------------------------------------------===//
+
+namespace llvm {
+ /// MachOCodeEmitter - This class is used by the MachOWriter to emit the code
+ /// for functions to the Mach-O file.
+ class MachOCodeEmitter : public MachineCodeEmitter {
+ MachOWriter &MOW;
+
+ /// Target machine description.
+ TargetMachine &TM;
+
+ /// is64Bit/isLittleEndian - This information is inferred from the target
+ /// machine directly, indicating what header values and flags to set.
+ bool is64Bit, isLittleEndian;
+
+ /// Relocations - These are the relocations that the function needs, as
+ /// emitted.
+ std::vector<MachineRelocation> Relocations;
+
+ /// CPLocations - This is a map of constant pool indices to offsets from the
+ /// start of the section for that constant pool index.
+ std::vector<intptr_t> CPLocations;
+
+ /// CPSections - This is a map of constant pool indices to the MachOSection
+ /// containing the constant pool entry for that index.
+ std::vector<unsigned> CPSections;
+
+ /// JTLocations - This is a map of jump table indices to offsets from the
+ /// start of the section for that jump table index.
+ std::vector<intptr_t> JTLocations;
+
+ /// MBBLocations - This vector is a mapping from MBB ID's to their address.
+ /// It is filled in by the StartMachineBasicBlock callback and queried by
+ /// the getMachineBasicBlockAddress callback.
+ std::vector<intptr_t> MBBLocations;
+
+ public:
+ MachOCodeEmitter(MachOWriter &mow) : MOW(mow), TM(MOW.TM) {
+ is64Bit = TM.getTargetData()->getPointerSizeInBits() == 64;
+ isLittleEndian = TM.getTargetData()->isLittleEndian();
+ }
+
+ virtual void startFunction(MachineFunction &MF);
+ virtual bool finishFunction(MachineFunction &MF);
+
+ virtual void addRelocation(const MachineRelocation &MR) {
+ Relocations.push_back(MR);
+ }
+
+ void emitConstantPool(MachineConstantPool *MCP);
+ void emitJumpTables(MachineJumpTableInfo *MJTI);
+
+ virtual intptr_t getConstantPoolEntryAddress(unsigned Index) const {
+ assert(CPLocations.size() > Index && "CP not emitted!");
+ return CPLocations[Index];
+ }
+ virtual intptr_t getJumpTableEntryAddress(unsigned Index) const {
+ assert(JTLocations.size() > Index && "JT not emitted!");
+ return JTLocations[Index];
+ }
+
+ virtual void StartMachineBasicBlock(MachineBasicBlock *MBB) {
+ if (MBBLocations.size() <= (unsigned)MBB->getNumber())
+ MBBLocations.resize((MBB->getNumber()+1)*2);
+ MBBLocations[MBB->getNumber()] = getCurrentPCOffset();
+ }
+
+ virtual intptr_t getMachineBasicBlockAddress(MachineBasicBlock *MBB) const {
+ assert(MBBLocations.size() > (unsigned)MBB->getNumber() &&
+ MBBLocations[MBB->getNumber()] && "MBB not emitted!");
+ return MBBLocations[MBB->getNumber()];
+ }
+
+ /// JIT SPECIFIC FUNCTIONS - DO NOT IMPLEMENT THESE HERE!
+ virtual void startFunctionStub(unsigned StubSize, unsigned Alignment = 1) {
+ assert(0 && "JIT specific function called!");
+ abort();
+ }
+ virtual void *finishFunctionStub(const Function *F) {
+ assert(0 && "JIT specific function called!");
+ abort();
+ return 0;
+ }
+ };
+}
+
+/// startFunction - This callback is invoked when a new machine function is
+/// about to be emitted.
+void MachOCodeEmitter::startFunction(MachineFunction &MF) {
+ const TargetData *TD = TM.getTargetData();
+ const Function *F = MF.getFunction();
+
+ // Align the output buffer to the appropriate alignment, power of 2.
+ unsigned FnAlign = F->getAlignment();
+ unsigned TDAlign = TD->getPrefTypeAlignment(F->getType());
+ unsigned Align = Log2_32(std::max(FnAlign, TDAlign));
+ assert(!(Align & (Align-1)) && "Alignment is not a power of two!");
+
+ // Get the Mach-O Section that this function belongs in.
+ MachOWriter::MachOSection *MOS = MOW.getTextSection();
+
+ // FIXME: better memory management
+ MOS->SectionData.reserve(4096);
+ BufferBegin = &MOS->SectionData[0];
+ BufferEnd = BufferBegin + MOS->SectionData.capacity();
+
+ // Upgrade the section alignment if required.
+ if (MOS->align < Align) MOS->align = Align;
+
+ // Round the size up to the correct alignment for starting the new function.
+ if ((MOS->size & ((1 << Align) - 1)) != 0) {
+ MOS->size += (1 << Align);
+ MOS->size &= ~((1 << Align) - 1);
+ }
+
+ // FIXME: Using MOS->size directly here instead of calculating it from the
+ // output buffer size (impossible because the code emitter deals only in raw
+ // bytes) forces us to manually synchronize size and write padding zero bytes
+ // to the output buffer for all non-text sections. For text sections, we do
+ // not synchonize the output buffer, and we just blow up if anyone tries to
+ // write non-code to it. An assert should probably be added to
+ // AddSymbolToSection to prevent calling it on the text section.
+ CurBufferPtr = BufferBegin + MOS->size;
+
+ // Clear per-function data structures.
+ CPLocations.clear();
+ CPSections.clear();
+ JTLocations.clear();
+ MBBLocations.clear();
+}
+
+/// finishFunction - This callback is invoked after the function is completely
+/// finished.
+bool MachOCodeEmitter::finishFunction(MachineFunction &MF) {
+ // Get the Mach-O Section that this function belongs in.
+ MachOWriter::MachOSection *MOS = MOW.getTextSection();
+
+ // Get a symbol for the function to add to the symbol table
+ // FIXME: it seems like we should call something like AddSymbolToSection
+ // in startFunction rather than changing the section size and symbol n_value
+ // here.
+ const GlobalValue *FuncV = MF.getFunction();
+ MachOSym FnSym(FuncV, MOW.Mang->getValueName(FuncV), MOS->Index, TM);
+ FnSym.n_value = MOS->size;
+ MOS->size = CurBufferPtr - BufferBegin;
+
+ // Emit constant pool to appropriate section(s)
+ emitConstantPool(MF.getConstantPool());
+
+ // Emit jump tables to appropriate section
+ emitJumpTables(MF.getJumpTableInfo());
+
+ // If we have emitted any relocations to function-specific objects such as
+ // basic blocks, constant pools entries, or jump tables, record their
+ // addresses now so that we can rewrite them with the correct addresses
+ // later.
+ for (unsigned i = 0, e = Relocations.size(); i != e; ++i) {
+ MachineRelocation &MR = Relocations[i];
+ intptr_t Addr;
+
+ if (MR.isBasicBlock()) {
+ Addr = getMachineBasicBlockAddress(MR.getBasicBlock());
+ MR.setConstantVal(MOS->Index);
+ MR.setResultPointer((void*)Addr);
+ } else if (MR.isJumpTableIndex()) {
+ Addr = getJumpTableEntryAddress(MR.getJumpTableIndex());
+ MR.setConstantVal(MOW.getJumpTableSection()->Index);
+ MR.setResultPointer((void*)Addr);
+ } else if (MR.isConstantPoolIndex()) {
+ Addr = getConstantPoolEntryAddress(MR.getConstantPoolIndex());
+ MR.setConstantVal(CPSections[MR.getConstantPoolIndex()]);
+ MR.setResultPointer((void*)Addr);
+ } else if (MR.isGlobalValue()) {
+ // FIXME: This should be a set or something that uniques
+ MOW.PendingGlobals.push_back(MR.getGlobalValue());
+ } else {
+ assert(0 && "Unhandled relocation type");
+ }
+ MOS->Relocations.push_back(MR);
+ }
+ Relocations.clear();
+
+ // Finally, add it to the symtab.
+ MOW.SymbolTable.push_back(FnSym);
+ return false;
+}
+
+/// emitConstantPool - For each constant pool entry, figure out which section
+/// the constant should live in, allocate space for it, and emit it to the
+/// Section data buffer.
+void MachOCodeEmitter::emitConstantPool(MachineConstantPool *MCP) {
+ const std::vector<MachineConstantPoolEntry> &CP = MCP->getConstants();
+ if (CP.empty()) return;
+
+ // FIXME: handle PIC codegen
+ bool isPIC = TM.getRelocationModel() == Reloc::PIC_;
+ assert(!isPIC && "PIC codegen not yet handled for mach-o jump tables!");
+
+ // Although there is no strict necessity that I am aware of, we will do what
+ // gcc for OS X does and put each constant pool entry in a section of constant
+ // objects of a certain size. That means that float constants go in the
+ // literal4 section, and double objects go in literal8, etc.
+ //
+ // FIXME: revisit this decision if we ever do the "stick everything into one
+ // "giant object for PIC" optimization.
+ for (unsigned i = 0, e = CP.size(); i != e; ++i) {
+ const Type *Ty = CP[i].getType();
+ unsigned Size = TM.getTargetData()->getTypeSize(Ty);
+
+ MachOWriter::MachOSection *Sec = MOW.getConstSection(CP[i].Val.ConstVal);
+ OutputBuffer SecDataOut(Sec->SectionData, is64Bit, isLittleEndian);
+
+ CPLocations.push_back(Sec->SectionData.size());
+ CPSections.push_back(Sec->Index);
+
+ // FIXME: remove when we have unified size + output buffer
+ Sec->size += Size;
+
+ // Allocate space in the section for the global.
+ // FIXME: need alignment?
+ // FIXME: share between here and AddSymbolToSection?
+ for (unsigned j = 0; j < Size; ++j)
+ SecDataOut.outbyte(0);
+
+ MOW.InitMem(CP[i].Val.ConstVal, &Sec->SectionData[0], CPLocations[i],
+ TM.getTargetData(), Sec->Relocations);
+ }
+}
+
+/// emitJumpTables - Emit all the jump tables for a given jump table info
+/// record to the appropriate section.
+void MachOCodeEmitter::emitJumpTables(MachineJumpTableInfo *MJTI) {
+ const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables();
+ if (JT.empty()) return;
+
+ // FIXME: handle PIC codegen
+ bool isPIC = TM.getRelocationModel() == Reloc::PIC_;
+ assert(!isPIC && "PIC codegen not yet handled for mach-o jump tables!");
+
+ MachOWriter::MachOSection *Sec = MOW.getJumpTableSection();
+ unsigned TextSecIndex = MOW.getTextSection()->Index;
+ OutputBuffer SecDataOut(Sec->SectionData, is64Bit, isLittleEndian);
+
+ for (unsigned i = 0, e = JT.size(); i != e; ++i) {
+ // For each jump table, record its offset from the start of the section,
+ // reserve space for the relocations to the MBBs, and add the relocations.
+ const std::vector<MachineBasicBlock*> &MBBs = JT[i].MBBs;
+ JTLocations.push_back(Sec->SectionData.size());
+ for (unsigned mi = 0, me = MBBs.size(); mi != me; ++mi) {
+ MachineRelocation MR(MOW.GetJTRelocation(Sec->SectionData.size(),
+ MBBs[mi]));
+ MR.setResultPointer((void *)JTLocations[i]);
+ MR.setConstantVal(TextSecIndex);
+ Sec->Relocations.push_back(MR);
+ SecDataOut.outaddr(0);
+ }
+ }
+ // FIXME: remove when we have unified size + output buffer
+ Sec->size = Sec->SectionData.size();
+}
+
+//===----------------------------------------------------------------------===//
+// MachOWriter Implementation
+//===----------------------------------------------------------------------===//
+
+char MachOWriter::ID = 0;
+MachOWriter::MachOWriter(std::ostream &o, TargetMachine &tm)
+ : MachineFunctionPass((intptr_t)&ID), O(o), TM(tm) {
+ is64Bit = TM.getTargetData()->getPointerSizeInBits() == 64;
+ isLittleEndian = TM.getTargetData()->isLittleEndian();
+
+ // Create the machine code emitter object for this target.
+ MCE = new MachOCodeEmitter(*this);
+}
+
+MachOWriter::~MachOWriter() {
+ delete MCE;
+}
+
+void MachOWriter::AddSymbolToSection(MachOSection *Sec, GlobalVariable *GV) {
+ const Type *Ty = GV->getType()->getElementType();
+ unsigned Size = TM.getTargetData()->getTypeSize(Ty);
+ unsigned Align = GV->getAlignment();
+ if (Align == 0)
+ Align = TM.getTargetData()->getPrefTypeAlignment(Ty);
+
+ // Reserve space in the .bss section for this symbol while maintaining the
+ // desired section alignment, which must be at least as much as required by
+ // this symbol.
+ OutputBuffer SecDataOut(Sec->SectionData, is64Bit, isLittleEndian);
+
+ if (Align) {
+ uint64_t OrigSize = Sec->size;
+ Align = Log2_32(Align);
+ Sec->align = std::max(unsigned(Sec->align), Align);
+ Sec->size = (Sec->size + Align - 1) & ~(Align-1);
+
+ // Add alignment padding to buffer as well.
+ // FIXME: remove when we have unified size + output buffer
+ unsigned AlignedSize = Sec->size - OrigSize;
+ for (unsigned i = 0; i < AlignedSize; ++i)
+ SecDataOut.outbyte(0);
+ }
+ // Globals without external linkage apparently do not go in the symbol table.
+ if (GV->getLinkage() != GlobalValue::InternalLinkage) {
+ MachOSym Sym(GV, Mang->getValueName(GV), Sec->Index, TM);
+ Sym.n_value = Sec->size;
+ SymbolTable.push_back(Sym);
+ }
+
+ // Record the offset of the symbol, and then allocate space for it.
+ // FIXME: remove when we have unified size + output buffer
+ Sec->size += Size;
+
+ // Now that we know what section the GlovalVariable is going to be emitted
+ // into, update our mappings.
+ // FIXME: We may also need to update this when outputting non-GlobalVariable
+ // GlobalValues such as functions.
+ GVSection[GV] = Sec;
+ GVOffset[GV] = Sec->SectionData.size();
+
+ // Allocate space in the section for the global.
+ for (unsigned i = 0; i < Size; ++i)
+ SecDataOut.outbyte(0);
+}
+
+void MachOWriter::EmitGlobal(GlobalVariable *GV) {
+ const Type *Ty = GV->getType()->getElementType();
+ unsigned Size = TM.getTargetData()->getTypeSize(Ty);
+ bool NoInit = !GV->hasInitializer();
+
+ // If this global has a zero initializer, it is part of the .bss or common
+ // section.
+ if (NoInit || GV->getInitializer()->isNullValue()) {
+ // If this global is part of the common block, add it now. Variables are
+ // part of the common block if they are zero initialized and allowed to be
+ // merged with other symbols.
+ if (NoInit || GV->hasLinkOnceLinkage() || GV->hasWeakLinkage()) {
+ MachOSym ExtOrCommonSym(GV, Mang->getValueName(GV), MachOSym::NO_SECT,TM);
+ // For undefined (N_UNDF) external (N_EXT) types, n_value is the size in
+ // bytes of the symbol.
+ ExtOrCommonSym.n_value = Size;
+ SymbolTable.push_back(ExtOrCommonSym);
+ // Remember that we've seen this symbol
+ GVOffset[GV] = Size;
+ return;
+ }
+ // Otherwise, this symbol is part of the .bss section.
+ MachOSection *BSS = getBSSSection();
+ AddSymbolToSection(BSS, GV);
+ return;
+ }
+
+ // Scalar read-only data goes in a literal section if the scalar is 4, 8, or
+ // 16 bytes, or a cstring. Other read only data goes into a regular const
+ // section. Read-write data goes in the data section.
+ MachOSection *Sec = GV->isConstant() ? getConstSection(GV->getInitializer()) :
+ getDataSection();
+ AddSymbolToSection(Sec, GV);
+ InitMem(GV->getInitializer(), &Sec->SectionData[0], GVOffset[GV],
+ TM.getTargetData(), Sec->Relocations);
+}
+
+
+bool MachOWriter::runOnMachineFunction(MachineFunction &MF) {
+ // Nothing to do here, this is all done through the MCE object.
+ return false;
+}
+
+bool MachOWriter::doInitialization(Module &M) {
+ // Set the magic value, now that we know the pointer size and endianness
+ Header.setMagic(isLittleEndian, is64Bit);
+
+ // Set the file type
+ // FIXME: this only works for object files, we do not support the creation
+ // of dynamic libraries or executables at this time.
+ Header.filetype = MachOHeader::MH_OBJECT;
+
+ Mang = new Mangler(M);
+ return false;
+}
+
+/// doFinalization - Now that the module has been completely processed, emit
+/// the Mach-O file to 'O'.
+bool MachOWriter::doFinalization(Module &M) {
+ // FIXME: we don't handle debug info yet, we should probably do that.
+
+ // Okay, the.text section has been completed, build the .data, .bss, and
+ // "common" sections next.
+ for (Module::global_iterator I = M.global_begin(), E = M.global_end();
+ I != E; ++I)
+ EmitGlobal(I);
+
+ // Emit the header and load commands.
+ EmitHeaderAndLoadCommands();
+
+ // Emit the various sections and their relocation info.
+ EmitSections();
+
+ // Write the symbol table and the string table to the end of the file.
+ O.write((char*)&SymT[0], SymT.size());
+ O.write((char*)&StrT[0], StrT.size());
+
+ // We are done with the abstract symbols.
+ SectionList.clear();
+ SymbolTable.clear();
+ DynamicSymbolTable.clear();
+
+ // Release the name mangler object.
+ delete Mang; Mang = 0;
+ return false;
+}
+
+void MachOWriter::EmitHeaderAndLoadCommands() {
+ // Step #0: Fill in the segment load command size, since we need it to figure
+ // out the rest of the header fields
+ MachOSegment SEG("", is64Bit);
+ SEG.nsects = SectionList.size();
+ SEG.cmdsize = SEG.cmdSize(is64Bit) +
+ SEG.nsects * SectionList[0]->cmdSize(is64Bit);
+
+ // Step #1: calculate the number of load commands. We always have at least
+ // one, for the LC_SEGMENT load command, plus two for the normal
+ // and dynamic symbol tables, if there are any symbols.
+ Header.ncmds = SymbolTable.empty() ? 1 : 3;
+
+ // Step #2: calculate the size of the load commands
+ Header.sizeofcmds = SEG.cmdsize;
+ if (!SymbolTable.empty())
+ Header.sizeofcmds += SymTab.cmdsize + DySymTab.cmdsize;
+
+ // Step #3: write the header to the file
+ // Local alias to shortenify coming code.
+ DataBuffer &FH = Header.HeaderData;
+ OutputBuffer FHOut(FH, is64Bit, isLittleEndian);
+
+ FHOut.outword(Header.magic);
+ FHOut.outword(TM.getMachOWriterInfo()->getCPUType());
+ FHOut.outword(TM.getMachOWriterInfo()->getCPUSubType());
+ FHOut.outword(Header.filetype);
+ FHOut.outword(Header.ncmds);
+ FHOut.outword(Header.sizeofcmds);
+ FHOut.outword(Header.flags);
+ if (is64Bit)
+ FHOut.outword(Header.reserved);
+
+ // Step #4: Finish filling in the segment load command and write it out
+ for (std::vector<MachOSection*>::iterator I = SectionList.begin(),
+ E = SectionList.end(); I != E; ++I)
+ SEG.filesize += (*I)->size;
+
+ SEG.vmsize = SEG.filesize;
+ SEG.fileoff = Header.cmdSize(is64Bit) + Header.sizeofcmds;
+
+ FHOut.outword(SEG.cmd);
+ FHOut.outword(SEG.cmdsize);
+ FHOut.outstring(SEG.segname, 16);
+ FHOut.outaddr(SEG.vmaddr);
+ FHOut.outaddr(SEG.vmsize);
+ FHOut.outaddr(SEG.fileoff);
+ FHOut.outaddr(SEG.filesize);
+ FHOut.outword(SEG.maxprot);
+ FHOut.outword(SEG.initprot);
+ FHOut.outword(SEG.nsects);
+ FHOut.outword(SEG.flags);
+
+ // Step #5: Finish filling in the fields of the MachOSections
+ uint64_t currentAddr = 0;
+ for (std::vector<MachOSection*>::iterator I = SectionList.begin(),
+ E = SectionList.end(); I != E; ++I) {
+ MachOSection *MOS = *I;
+ MOS->addr = currentAddr;
+ MOS->offset = currentAddr + SEG.fileoff;
+
+ // FIXME: do we need to do something with alignment here?
+ currentAddr += MOS->size;
+ }
+
+ // Step #6: Emit the symbol table to temporary buffers, so that we know the
+ // size of the string table when we write the next load command. This also
+ // sorts and assigns indices to each of the symbols, which is necessary for
+ // emitting relocations to externally-defined objects.
+ BufferSymbolAndStringTable();
+
+ // Step #7: Calculate the number of relocations for each section and write out
+ // the section commands for each section
+ currentAddr += SEG.fileoff;
+ for (std::vector<MachOSection*>::iterator I = SectionList.begin(),
+ E = SectionList.end(); I != E; ++I) {
+ MachOSection *MOS = *I;
+ // Convert the relocations to target-specific relocations, and fill in the
+ // relocation offset for this section.
+ CalculateRelocations(*MOS);
+ MOS->reloff = MOS->nreloc ? currentAddr : 0;
+ currentAddr += MOS->nreloc * 8;
+
+ // write the finalized section command to the output buffer
+ FHOut.outstring(MOS->sectname, 16);
+ FHOut.outstring(MOS->segname, 16);
+ FHOut.outaddr(MOS->addr);
+ FHOut.outaddr(MOS->size);
+ FHOut.outword(MOS->offset);
+ FHOut.outword(MOS->align);
+ FHOut.outword(MOS->reloff);
+ FHOut.outword(MOS->nreloc);
+ FHOut.outword(MOS->flags);
+ FHOut.outword(MOS->reserved1);
+ FHOut.outword(MOS->reserved2);
+ if (is64Bit)
+ FHOut.outword(MOS->reserved3);
+ }
+
+ // Step #8: Emit LC_SYMTAB/LC_DYSYMTAB load commands
+ SymTab.symoff = currentAddr;
+ SymTab.nsyms = SymbolTable.size();
+ SymTab.stroff = SymTab.symoff + SymT.size();
+ SymTab.strsize = StrT.size();
+ FHOut.outword(SymTab.cmd);
+ FHOut.outword(SymTab.cmdsize);
+ FHOut.outword(SymTab.symoff);
+ FHOut.outword(SymTab.nsyms);
+ FHOut.outword(SymTab.stroff);
+ FHOut.outword(SymTab.strsize);
+
+ // FIXME: set DySymTab fields appropriately
+ // We should probably just update these in BufferSymbolAndStringTable since
+ // thats where we're partitioning up the different kinds of symbols.
+ FHOut.outword(DySymTab.cmd);
+ FHOut.outword(DySymTab.cmdsize);
+ FHOut.outword(DySymTab.ilocalsym);
+ FHOut.outword(DySymTab.nlocalsym);
+ FHOut.outword(DySymTab.iextdefsym);
+ FHOut.outword(DySymTab.nextdefsym);
+ FHOut.outword(DySymTab.iundefsym);
+ FHOut.outword(DySymTab.nundefsym);
+ FHOut.outword(DySymTab.tocoff);
+ FHOut.outword(DySymTab.ntoc);
+ FHOut.outword(DySymTab.modtaboff);
+ FHOut.outword(DySymTab.nmodtab);
+ FHOut.outword(DySymTab.extrefsymoff);
+ FHOut.outword(DySymTab.nextrefsyms);
+ FHOut.outword(DySymTab.indirectsymoff);
+ FHOut.outword(DySymTab.nindirectsyms);
+ FHOut.outword(DySymTab.extreloff);
+ FHOut.outword(DySymTab.nextrel);
+ FHOut.outword(DySymTab.locreloff);
+ FHOut.outword(DySymTab.nlocrel);
+
+ O.write((char*)&FH[0], FH.size());
+}
+
+/// EmitSections - Now that we have constructed the file header and load
+/// commands, emit the data for each section to the file.
+void MachOWriter::EmitSections() {
+ for (std::vector<MachOSection*>::iterator I = SectionList.begin(),
+ E = SectionList.end(); I != E; ++I)
+ // Emit the contents of each section
+ O.write((char*)&(*I)->SectionData[0], (*I)->size);
+ for (std::vector<MachOSection*>::iterator I = SectionList.begin(),
+ E = SectionList.end(); I != E; ++I)
+ // Emit the relocation entry data for each section.
+ O.write((char*)&(*I)->RelocBuffer[0], (*I)->RelocBuffer.size());
+}
+
+/// PartitionByLocal - Simple boolean predicate that returns true if Sym is
+/// a local symbol rather than an external symbol.
+bool MachOWriter::PartitionByLocal(const MachOSym &Sym) {
+ return (Sym.n_type & (MachOSym::N_EXT | MachOSym::N_PEXT)) == 0;
+}
+
+/// PartitionByDefined - Simple boolean predicate that returns true if Sym is
+/// defined in this module.
+bool MachOWriter::PartitionByDefined(const MachOSym &Sym) {
+ // FIXME: Do N_ABS or N_INDR count as defined?
+ return (Sym.n_type & MachOSym::N_SECT) == MachOSym::N_SECT;
+}
+
+/// BufferSymbolAndStringTable - Sort the symbols we encountered and assign them
+/// each a string table index so that they appear in the correct order in the
+/// output file.
+void MachOWriter::BufferSymbolAndStringTable() {
+ // The order of the symbol table is:
+ // 1. local symbols
+ // 2. defined external symbols (sorted by name)
+ // 3. undefined external symbols (sorted by name)
+
+ // Before sorting the symbols, check the PendingGlobals for any undefined
+ // globals that need to be put in the symbol table.
+ for (std::vector<GlobalValue*>::iterator I = PendingGlobals.begin(),
+ E = PendingGlobals.end(); I != E; ++I) {
+ if (GVOffset[*I] == 0 && GVSection[*I] == 0) {
+ MachOSym UndfSym(*I, Mang->getValueName(*I), MachOSym::NO_SECT, TM);
+ SymbolTable.push_back(UndfSym);
+ GVOffset[*I] = -1;
+ }
+ }
+
+ // Sort the symbols by name, so that when we partition the symbols by scope
+ // of definition, we won't have to sort by name within each partition.
+ std::sort(SymbolTable.begin(), SymbolTable.end(), MachOSymCmp());
+
+ // Parition the symbol table entries so that all local symbols come before
+ // all symbols with external linkage. { 1 | 2 3 }
+ std::partition(SymbolTable.begin(), SymbolTable.end(), PartitionByLocal);
+
+ // Advance iterator to beginning of external symbols and partition so that
+ // all external symbols defined in this module come before all external
+ // symbols defined elsewhere. { 1 | 2 | 3 }
+ for (std::vector<MachOSym>::iterator I = SymbolTable.begin(),
+ E = SymbolTable.end(); I != E; ++I) {
+ if (!PartitionByLocal(*I)) {
+ std::partition(I, E, PartitionByDefined);
+ break;
+ }
+ }
+
+ // Calculate the starting index for each of the local, extern defined, and
+ // undefined symbols, as well as the number of each to put in the LC_DYSYMTAB
+ // load command.
+ for (std::vector<MachOSym>::iterator I = SymbolTable.begin(),
+ E = SymbolTable.end(); I != E; ++I) {
+ if (PartitionByLocal(*I)) {
+ ++DySymTab.nlocalsym;
+ ++DySymTab.iextdefsym;
+ ++DySymTab.iundefsym;
+ } else if (PartitionByDefined(*I)) {
+ ++DySymTab.nextdefsym;
+ ++DySymTab.iundefsym;
+ } else {
+ ++DySymTab.nundefsym;
+ }
+ }
+
+ // Write out a leading zero byte when emitting string table, for n_strx == 0
+ // which means an empty string.
+ OutputBuffer StrTOut(StrT, is64Bit, isLittleEndian);
+ StrTOut.outbyte(0);
+
+ // The order of the string table is:
+ // 1. strings for external symbols
+ // 2. strings for local symbols
+ // Since this is the opposite order from the symbol table, which we have just
+ // sorted, we can walk the symbol table backwards to output the string table.
+ for (std::vector<MachOSym>::reverse_iterator I = SymbolTable.rbegin(),
+ E = SymbolTable.rend(); I != E; ++I) {
+ if (I->GVName == "") {
+ I->n_strx = 0;
+ } else {
+ I->n_strx = StrT.size();
+ StrTOut.outstring(I->GVName, I->GVName.length()+1);
+ }
+ }
+
+ OutputBuffer SymTOut(SymT, is64Bit, isLittleEndian);
+
+ unsigned index = 0;
+ for (std::vector<MachOSym>::iterator I = SymbolTable.begin(),
+ E = SymbolTable.end(); I != E; ++I, ++index) {
+ // Add the section base address to the section offset in the n_value field
+ // to calculate the full address.
+ // FIXME: handle symbols where the n_value field is not the address
+ GlobalValue *GV = const_cast<GlobalValue*>(I->GV);
+ if (GV && GVSection[GV])
+ I->n_value += GVSection[GV]->addr;
+ if (GV && (GVOffset[GV] == -1))
+ GVOffset[GV] = index;
+
+ // Emit nlist to buffer
+ SymTOut.outword(I->n_strx);
+ SymTOut.outbyte(I->n_type);
+ SymTOut.outbyte(I->n_sect);
+ SymTOut.outhalf(I->n_desc);
+ SymTOut.outaddr(I->n_value);
+ }
+}
+
+/// CalculateRelocations - For each MachineRelocation in the current section,
+/// calculate the index of the section containing the object to be relocated,
+/// and the offset into that section. From this information, create the
+/// appropriate target-specific MachORelocation type and add buffer it to be
+/// written out after we are finished writing out sections.
+void MachOWriter::CalculateRelocations(MachOSection &MOS) {
+ for (unsigned i = 0, e = MOS.Relocations.size(); i != e; ++i) {
+ MachineRelocation &MR = MOS.Relocations[i];
+ unsigned TargetSection = MR.getConstantVal();
+ unsigned TargetAddr = 0;
+ unsigned TargetIndex = 0;
+
+ // This is a scattered relocation entry if it points to a global value with
+ // a non-zero offset.
+ bool Scattered = false;
+ bool Extern = false;
+
+ // Since we may not have seen the GlobalValue we were interested in yet at
+ // the time we emitted the relocation for it, fix it up now so that it
+ // points to the offset into the correct section.
+ if (MR.isGlobalValue()) {
+ GlobalValue *GV = MR.getGlobalValue();
+ MachOSection *MOSPtr = GVSection[GV];
+ intptr_t Offset = GVOffset[GV];
+
+ // If we have never seen the global before, it must be to a symbol
+ // defined in another module (N_UNDF).
+ if (!MOSPtr) {
+ // FIXME: need to append stub suffix
+ Extern = true;
+ TargetAddr = 0;
+ TargetIndex = GVOffset[GV];
+ } else {
+ Scattered = TargetSection != 0;
+ TargetSection = MOSPtr->Index;
+ }
+ MR.setResultPointer((void*)Offset);
+ }
+
+ // If the symbol is locally defined, pass in the address of the section and
+ // the section index to the code which will generate the target relocation.
+ if (!Extern) {
+ MachOSection &To = *SectionList[TargetSection - 1];
+ TargetAddr = To.addr;
+ TargetIndex = To.Index;
+ }
+
+ OutputBuffer RelocOut(MOS.RelocBuffer, is64Bit, isLittleEndian);
+ OutputBuffer SecOut(MOS.SectionData, is64Bit, isLittleEndian);
+
+ MOS.nreloc += GetTargetRelocation(MR, MOS.Index, TargetAddr, TargetIndex,
+ RelocOut, SecOut, Scattered, Extern);
+ }
+}
+
+// InitMem - Write the value of a Constant to the specified memory location,
+// converting it into bytes and relocations.
+void MachOWriter::InitMem(const Constant *C, void *Addr, intptr_t Offset,
+ const TargetData *TD,
+ std::vector<MachineRelocation> &MRs) {
+ typedef std::pair<const Constant*, intptr_t> CPair;
+ std::vector<CPair> WorkList;
+
+ WorkList.push_back(CPair(C,(intptr_t)Addr + Offset));
+
+ intptr_t ScatteredOffset = 0;
+
+ while (!WorkList.empty()) {
+ const Constant *PC = WorkList.back().first;
+ intptr_t PA = WorkList.back().second;
+ WorkList.pop_back();
+
+ if (isa<UndefValue>(PC)) {
+ continue;
+ } else if (const ConstantVector *CP = dyn_cast<ConstantVector>(PC)) {
+ unsigned ElementSize = TD->getTypeSize(CP->getType()->getElementType());
+ for (unsigned i = 0, e = CP->getNumOperands(); i != e; ++i)
+ WorkList.push_back(CPair(CP->getOperand(i), PA+i*ElementSize));
+ } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(PC)) {
+ //
+ // FIXME: Handle ConstantExpression. See EE::getConstantValue()
+ //
+ switch (CE->getOpcode()) {
+ case Instruction::GetElementPtr: {
+ SmallVector<Value*, 8> Indices(CE->op_begin()+1, CE->op_end());
+ ScatteredOffset = TD->getIndexedOffset(CE->getOperand(0)->getType(),
+ &Indices[0], Indices.size());
+ WorkList.push_back(CPair(CE->getOperand(0), PA));
+ break;
+ }
+ case Instruction::Add:
+ default:
+ cerr << "ConstantExpr not handled as global var init: " << *CE << "\n";
+ abort();
+ break;
+ }
+ } else if (PC->getType()->isFirstClassType()) {
+ unsigned char *ptr = (unsigned char *)PA;
+ switch (PC->getType()->getTypeID()) {
+ case Type::IntegerTyID: {
+ unsigned NumBits = cast<IntegerType>(PC->getType())->getBitWidth();
+ uint64_t val = cast<ConstantInt>(PC)->getZExtValue();
+ if (NumBits <= 8)
+ ptr[0] = val;
+ else if (NumBits <= 16) {
+ if (TD->isBigEndian())
+ val = ByteSwap_16(val);
+ ptr[0] = val;
+ ptr[1] = val >> 8;
+ } else if (NumBits <= 32) {
+ if (TD->isBigEndian())
+ val = ByteSwap_32(val);
+ ptr[0] = val;
+ ptr[1] = val >> 8;
+ ptr[2] = val >> 16;
+ ptr[3] = val >> 24;
+ } else if (NumBits <= 64) {
+ if (TD->isBigEndian())
+ val = ByteSwap_64(val);
+ ptr[0] = val;
+ ptr[1] = val >> 8;
+ ptr[2] = val >> 16;
+ ptr[3] = val >> 24;
+ ptr[4] = val >> 32;
+ ptr[5] = val >> 40;
+ ptr[6] = val >> 48;
+ ptr[7] = val >> 56;
+ } else {
+ assert(0 && "Not implemented: bit widths > 64");
+ }
+ break;
+ }
+ case Type::FloatTyID: {
+ uint64_t val = FloatToBits(cast<ConstantFP>(PC)->getValue());
+ if (TD->isBigEndian())
+ val = ByteSwap_32(val);
+ ptr[0] = val;
+ ptr[1] = val >> 8;
+ ptr[2] = val >> 16;
+ ptr[3] = val >> 24;
+ break;
+ }
+ case Type::DoubleTyID: {
+ uint64_t val = DoubleToBits(cast<ConstantFP>(PC)->getValue());
+ if (TD->isBigEndian())
+ val = ByteSwap_64(val);
+ ptr[0] = val;
+ ptr[1] = val >> 8;
+ ptr[2] = val >> 16;
+ ptr[3] = val >> 24;
+ ptr[4] = val >> 32;
+ ptr[5] = val >> 40;
+ ptr[6] = val >> 48;
+ ptr[7] = val >> 56;
+ break;
+ }
+ case Type::PointerTyID:
+ if (isa<ConstantPointerNull>(PC))
+ memset(ptr, 0, TD->getPointerSize());
+ else if (const GlobalValue* GV = dyn_cast<GlobalValue>(PC)) {
+ // FIXME: what about function stubs?
+ MRs.push_back(MachineRelocation::getGV(PA-(intptr_t)Addr,
+ MachineRelocation::VANILLA,
+ const_cast<GlobalValue*>(GV),
+ ScatteredOffset));
+ ScatteredOffset = 0;
+ } else
+ assert(0 && "Unknown constant pointer type!");
+ break;
+ default:
+ cerr << "ERROR: Constant unimp for type: " << *PC->getType() << "\n";
+ abort();
+ }
+ } else if (isa<ConstantAggregateZero>(PC)) {
+ memset((void*)PA, 0, (size_t)TD->getTypeSize(PC->getType()));
+ } else if (const ConstantArray *CPA = dyn_cast<ConstantArray>(PC)) {
+ unsigned ElementSize = TD->getTypeSize(CPA->getType()->getElementType());
+ for (unsigned i = 0, e = CPA->getNumOperands(); i != e; ++i)
+ WorkList.push_back(CPair(CPA->getOperand(i), PA+i*ElementSize));
+ } else if (const ConstantStruct *CPS = dyn_cast<ConstantStruct>(PC)) {
+ const StructLayout *SL =
+ TD->getStructLayout(cast<StructType>(CPS->getType()));
+ for (unsigned i = 0, e = CPS->getNumOperands(); i != e; ++i)
+ WorkList.push_back(CPair(CPS->getOperand(i),
+ PA+SL->getElementOffset(i)));
+ } else {
+ cerr << "Bad Type: " << *PC->getType() << "\n";
+ assert(0 && "Unknown constant type to initialize memory with!");
+ }
+ }
+}
+
+MachOSym::MachOSym(const GlobalValue *gv, std::string name, uint8_t sect,
+ TargetMachine &TM) :
+ GV(gv), n_strx(0), n_type(sect == NO_SECT ? N_UNDF : N_SECT), n_sect(sect),
+ n_desc(0), n_value(0) {
+
+ const TargetAsmInfo *TAI = TM.getTargetAsmInfo();
+
+ switch (GV->getLinkage()) {
+ default:
+ assert(0 && "Unexpected linkage type!");
+ break;
+ case GlobalValue::WeakLinkage:
+ case GlobalValue::LinkOnceLinkage:
+ assert(!isa<Function>(gv) && "Unexpected linkage type for Function!");
+ case GlobalValue::ExternalLinkage:
+ GVName = TAI->getGlobalPrefix() + name;
+ n_type |= GV->hasHiddenVisibility() ? N_PEXT : N_EXT;
+ break;
+ case GlobalValue::InternalLinkage:
+ GVName = TAI->getGlobalPrefix() + name;
+ break;
+ }
+}