diff options
| -rw-r--r-- | include/llvm/ExecutionEngine/RuntimeDyld.h | 1 | ||||
| -rw-r--r-- | lib/ExecutionEngine/RuntimeDyld/CMakeLists.txt | 1 | ||||
| -rw-r--r-- | lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp | 615 | ||||
| -rw-r--r-- | lib/ExecutionEngine/RuntimeDyld/RuntimeDyldImpl.h | 152 | ||||
| -rw-r--r-- | lib/ExecutionEngine/RuntimeDyld/RuntimeDyldMachO.cpp | 524 |
5 files changed, 694 insertions, 599 deletions
diff --git a/include/llvm/ExecutionEngine/RuntimeDyld.h b/include/llvm/ExecutionEngine/RuntimeDyld.h index 3dc65e33d4..724b9f09e0 100644 --- a/include/llvm/ExecutionEngine/RuntimeDyld.h +++ b/include/llvm/ExecutionEngine/RuntimeDyld.h @@ -53,6 +53,7 @@ class RuntimeDyld { // RuntimeDyldImpl is the actual class. RuntimeDyld is just the public // interface. RuntimeDyldImpl *Dyld; + RTDyldMemoryManager *MM; public: RuntimeDyld(RTDyldMemoryManager*); ~RuntimeDyld(); diff --git a/lib/ExecutionEngine/RuntimeDyld/CMakeLists.txt b/lib/ExecutionEngine/RuntimeDyld/CMakeLists.txt index 9e53f8757e..59bdfee3db 100644 --- a/lib/ExecutionEngine/RuntimeDyld/CMakeLists.txt +++ b/lib/ExecutionEngine/RuntimeDyld/CMakeLists.txt @@ -1,3 +1,4 @@ add_llvm_library(LLVMRuntimeDyld RuntimeDyld.cpp + RuntimeDyldMachO.cpp ) diff --git a/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp b/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp index eda4cbbad5..33dd705027 100644 --- a/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp +++ b/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp @@ -1,4 +1,4 @@ -//===-- RuntimeDyld.h - Run-time dynamic linker for MC-JIT ------*- C++ -*-===// +//===-- RuntimeDyld.cpp - Run-time dynamic linker for MC-JIT ------*- C++ -*-===// // // The LLVM Compiler Infrastructure // @@ -12,118 +12,15 @@ //===----------------------------------------------------------------------===// #define DEBUG_TYPE "dyld" -#include "llvm/ADT/OwningPtr.h" -#include "llvm/ADT/SmallVector.h" -#include "llvm/ADT/StringMap.h" -#include "llvm/ADT/StringRef.h" -#include "llvm/ADT/STLExtras.h" -#include "llvm/ADT/Twine.h" -#include "llvm/ExecutionEngine/RuntimeDyld.h" -#include "llvm/Object/MachOObject.h" -#include "llvm/Support/Debug.h" -#include "llvm/Support/ErrorHandling.h" -#include "llvm/Support/Format.h" -#include "llvm/Support/Memory.h" -#include "llvm/Support/MemoryBuffer.h" -#include "llvm/Support/system_error.h" -#include "llvm/Support/raw_ostream.h" +#include "RuntimeDyldImpl.h" using namespace llvm; using namespace llvm::object; // Empty out-of-line virtual destructor as the key function. RTDyldMemoryManager::~RTDyldMemoryManager() {} +RuntimeDyldImpl::~RuntimeDyldImpl() {} namespace llvm { -class RuntimeDyldImpl { - unsigned CPUType; - unsigned CPUSubtype; - - // The MemoryManager to load objects into. - RTDyldMemoryManager *MemMgr; - - // FIXME: This all assumes we're dealing with external symbols for anything - // explicitly referenced. I.e., we can index by name and things - // will work out. In practice, this may not be the case, so we - // should find a way to effectively generalize. - - // For each function, we have a MemoryBlock of it's instruction data. - StringMap<sys::MemoryBlock> Functions; - - // Master symbol table. As modules are loaded and external symbols are - // resolved, their addresses are stored here. - StringMap<uint8_t*> SymbolTable; - - // For each symbol, keep a list of relocations based on it. Anytime - // its address is reassigned (the JIT re-compiled the function, e.g.), - // the relocations get re-resolved. - struct RelocationEntry { - std::string Target; // Object this relocation is contained in. - uint64_t Offset; // Offset into the object for the relocation. - uint32_t Data; // Second word of the raw macho relocation entry. - int64_t Addend; // Addend encoded in the instruction itself, if any. - bool isResolved; // Has this relocation been resolved previously? - - RelocationEntry(StringRef t, uint64_t offset, uint32_t data, int64_t addend) - : Target(t), Offset(offset), Data(data), Addend(addend), - isResolved(false) {} - }; - typedef SmallVector<RelocationEntry, 4> RelocationList; - StringMap<RelocationList> Relocations; - - // FIXME: Also keep a map of all the relocations contained in an object. Use - // this to dynamically answer whether all of the relocations in it have - // been resolved or not. - - bool HasError; - std::string ErrorStr; - - // Set the error state and record an error string. - bool Error(const Twine &Msg) { - ErrorStr = Msg.str(); - HasError = true; - return true; - } - - void extractFunction(StringRef Name, uint8_t *StartAddress, - uint8_t *EndAddress); - bool resolveRelocation(uint8_t *Address, uint8_t *Value, bool isPCRel, - unsigned Type, unsigned Size); - bool resolveX86_64Relocation(uintptr_t Address, uintptr_t Value, bool isPCRel, - unsigned Type, unsigned Size); - bool resolveARMRelocation(uintptr_t Address, uintptr_t Value, bool isPCRel, - unsigned Type, unsigned Size); - - bool loadSegment32(const MachOObject *Obj, - const MachOObject::LoadCommandInfo *SegmentLCI, - const InMemoryStruct<macho::SymtabLoadCommand> &SymtabLC); - bool loadSegment64(const MachOObject *Obj, - const MachOObject::LoadCommandInfo *SegmentLCI, - const InMemoryStruct<macho::SymtabLoadCommand> &SymtabLC); - -public: - RuntimeDyldImpl(RTDyldMemoryManager *mm) : MemMgr(mm), HasError(false) {} - - bool loadObject(MemoryBuffer *InputBuffer); - - void *getSymbolAddress(StringRef Name) { - // FIXME: Just look up as a function for now. Overly simple of course. - // Work in progress. - return SymbolTable.lookup(Name); - } - - void resolveRelocations(); - - void reassignSymbolAddress(StringRef Name, uint8_t *Addr); - - // Is the linker in an error state? - bool hasError() { return HasError; } - - // Mark the error condition as handled and continue. - void clearError() { HasError = false; } - - // Get the error message. - StringRef getErrorString() { return ErrorStr; } -}; void RuntimeDyldImpl::extractFunction(StringRef Name, uint8_t *StartAddress, uint8_t *EndAddress) { @@ -144,472 +41,6 @@ void RuntimeDyldImpl::extractFunction(StringRef Name, uint8_t *StartAddress, DEBUG(dbgs() << " allocated to [" << Mem << ", " << Mem + Size << "]\n"); } -bool RuntimeDyldImpl:: -resolveRelocation(uint8_t *Address, uint8_t *Value, bool isPCRel, - unsigned Type, unsigned Size) { - // This just dispatches to the proper target specific routine. - switch (CPUType) { - default: assert(0 && "Unsupported CPU type!"); - case mach::CTM_x86_64: - return resolveX86_64Relocation((uintptr_t)Address, (uintptr_t)Value, - isPCRel, Type, Size); - case mach::CTM_ARM: - return resolveARMRelocation((uintptr_t)Address, (uintptr_t)Value, - isPCRel, Type, Size); - } - llvm_unreachable(""); -} - -bool RuntimeDyldImpl:: -resolveX86_64Relocation(uintptr_t Address, uintptr_t Value, - bool isPCRel, unsigned Type, - unsigned Size) { - // If the relocation is PC-relative, the value to be encoded is the - // pointer difference. - if (isPCRel) - // FIXME: It seems this value needs to be adjusted by 4 for an effective PC - // address. Is that expected? Only for branches, perhaps? - Value -= Address + 4; - - switch(Type) { - default: - llvm_unreachable("Invalid relocation type!"); - case macho::RIT_X86_64_Unsigned: - case macho::RIT_X86_64_Branch: { - // Mask in the target value a byte at a time (we don't have an alignment - // guarantee for the target address, so this is safest). - uint8_t *p = (uint8_t*)Address; - for (unsigned i = 0; i < Size; ++i) { - *p++ = (uint8_t)Value; - Value >>= 8; - } - return false; - } - case macho::RIT_X86_64_Signed: - case macho::RIT_X86_64_GOTLoad: - case macho::RIT_X86_64_GOT: - case macho::RIT_X86_64_Subtractor: - case macho::RIT_X86_64_Signed1: - case macho::RIT_X86_64_Signed2: - case macho::RIT_X86_64_Signed4: - case macho::RIT_X86_64_TLV: - return Error("Relocation type not implemented yet!"); - } - return false; -} - -bool RuntimeDyldImpl::resolveARMRelocation(uintptr_t Address, uintptr_t Value, - bool isPCRel, unsigned Type, - unsigned Size) { - // If the relocation is PC-relative, the value to be encoded is the - // pointer difference. - if (isPCRel) { - Value -= Address; - // ARM PCRel relocations have an effective-PC offset of two instructions - // (four bytes in Thumb mode, 8 bytes in ARM mode). - // FIXME: For now, assume ARM mode. - Value -= 8; - } - - switch(Type) { - default: - llvm_unreachable("Invalid relocation type!"); - case macho::RIT_Vanilla: { - llvm_unreachable("Invalid relocation type!"); - // Mask in the target value a byte at a time (we don't have an alignment - // guarantee for the target address, so this is safest). - uint8_t *p = (uint8_t*)Address; - for (unsigned i = 0; i < Size; ++i) { - *p++ = (uint8_t)Value; - Value >>= 8; - } - break; - } - case macho::RIT_ARM_Branch24Bit: { - // Mask the value into the target address. We know instructions are - // 32-bit aligned, so we can do it all at once. - uint32_t *p = (uint32_t*)Address; - // The low two bits of the value are not encoded. - Value >>= 2; - // Mask the value to 24 bits. - Value &= 0xffffff; - // FIXME: If the destination is a Thumb function (and the instruction - // is a non-predicated BL instruction), we need to change it to a BLX - // instruction instead. - - // Insert the value into the instruction. - *p = (*p & ~0xffffff) | Value; - break; - } - case macho::RIT_ARM_ThumbBranch22Bit: - case macho::RIT_ARM_ThumbBranch32Bit: - case macho::RIT_ARM_Half: - case macho::RIT_ARM_HalfDifference: - case macho::RIT_Pair: - case macho::RIT_Difference: - case macho::RIT_ARM_LocalDifference: - case macho::RIT_ARM_PreboundLazyPointer: - return Error("Relocation type not implemented yet!"); - } - return false; -} - -bool RuntimeDyldImpl:: -loadSegment32(const MachOObject *Obj, - const MachOObject::LoadCommandInfo *SegmentLCI, - const InMemoryStruct<macho::SymtabLoadCommand> &SymtabLC) { - InMemoryStruct<macho::SegmentLoadCommand> SegmentLC; - Obj->ReadSegmentLoadCommand(*SegmentLCI, SegmentLC); - if (!SegmentLC) - return Error("unable to load segment load command"); - - for (unsigned SectNum = 0; SectNum != SegmentLC->NumSections; ++SectNum) { - InMemoryStruct<macho::Section> Sect; - Obj->ReadSection(*SegmentLCI, SectNum, Sect); - if (!Sect) - return Error("unable to load section: '" + Twine(SectNum) + "'"); - - // FIXME: For the time being, we're only loading text segments. - if (Sect->Flags != 0x80000400) - continue; - - // Address and names of symbols in the section. - typedef std::pair<uint64_t, StringRef> SymbolEntry; - SmallVector<SymbolEntry, 64> Symbols; - // Index of all the names, in this section or not. Used when we're - // dealing with relocation entries. - SmallVector<StringRef, 64> SymbolNames; - for (unsigned i = 0; i != SymtabLC->NumSymbolTableEntries; ++i) { - InMemoryStruct<macho::SymbolTableEntry> STE; - Obj->ReadSymbolTableEntry(SymtabLC->SymbolTableOffset, i, STE); - if (!STE) - return Error("unable to read symbol: '" + Twine(i) + "'"); - if (STE->SectionIndex > SegmentLC->NumSections) - return Error("invalid section index for symbol: '" + Twine(i) + "'"); - // Get the symbol name. - StringRef Name = Obj->getStringAtIndex(STE->StringIndex); - SymbolNames.push_back(Name); - - // Just skip symbols not defined in this section. - if ((unsigned)STE->SectionIndex - 1 != SectNum) - continue; - - // FIXME: Check the symbol type and flags. - if (STE->Type != 0xF) // external, defined in this section. - continue; - // Flags == 0x8 marks a thumb function for ARM, which is fine as it - // doesn't require any special handling here. - if (STE->Flags != 0x0 && STE->Flags != 0x8) - continue; - - // Remember the symbol. - Symbols.push_back(SymbolEntry(STE->Value, Name)); - - DEBUG(dbgs() << "Function sym: '" << Name << "' @ " << - (Sect->Address + STE->Value) << "\n"); - } - // Sort the symbols by address, just in case they didn't come in that way. - array_pod_sort(Symbols.begin(), Symbols.end()); - - // If there weren't any functions (odd, but just in case...) - if (!Symbols.size()) - continue; - - // Extract the function data. - uint8_t *Base = (uint8_t*)Obj->getData(SegmentLC->FileOffset, - SegmentLC->FileSize).data(); - for (unsigned i = 0, e = Symbols.size() - 1; i != e; ++i) { - uint64_t StartOffset = Sect->Address + Symbols[i].first; - uint64_t EndOffset = Symbols[i + 1].first - 1; - DEBUG(dbgs() << "Extracting function: " << Symbols[i].second - << " from [" << StartOffset << ", " << EndOffset << "]\n"); - extractFunction(Symbols[i].second, Base + StartOffset, Base + EndOffset); - } - // The last symbol we do after since the end address is calculated - // differently because there is no next symbol to reference. - uint64_t StartOffset = Symbols[Symbols.size() - 1].first; - uint64_t EndOffset = Sect->Size - 1; - DEBUG(dbgs() << "Extracting function: " << Symbols[Symbols.size()-1].second - << " from [" << StartOffset << ", " << EndOffset << "]\n"); - extractFunction(Symbols[Symbols.size()-1].second, - Base + StartOffset, Base + EndOffset); - - // Now extract the relocation information for each function and process it. - for (unsigned j = 0; j != Sect->NumRelocationTableEntries; ++j) { - InMemoryStruct<macho::RelocationEntry> RE; - Obj->ReadRelocationEntry(Sect->RelocationTableOffset, j, RE); - if (RE->Word0 & macho::RF_Scattered) - return Error("NOT YET IMPLEMENTED: scattered relocations."); - // Word0 of the relocation is the offset into the section where the - // relocation should be applied. We need to translate that into an - // offset into a function since that's our atom. - uint32_t Offset = RE->Word0; - // Look for the function containing the address. This is used for JIT - // code, so the number of functions in section is almost always going - // to be very small (usually just one), so until we have use cases - // where that's not true, just use a trivial linear search. - unsigned SymbolNum; - unsigned NumSymbols = Symbols.size(); - assert(NumSymbols > 0 && Symbols[0].first <= Offset && - "No symbol containing relocation!"); - for (SymbolNum = 0; SymbolNum < NumSymbols - 1; ++SymbolNum) - if (Symbols[SymbolNum + 1].first > Offset) - break; - // Adjust the offset to be relative to the symbol. - Offset -= Symbols[SymbolNum].first; - // Get the name of the symbol containing the relocation. - StringRef TargetName = SymbolNames[SymbolNum]; - - bool isExtern = (RE->Word1 >> 27) & 1; - // Figure out the source symbol of the relocation. If isExtern is true, - // this relocation references the symbol table, otherwise it references - // a section in the same object, numbered from 1 through NumSections - // (SectionBases is [0, NumSections-1]). - // FIXME: Some targets (ARM) use internal relocations even for - // externally visible symbols, if the definition is in the same - // file as the reference. We need to convert those back to by-name - // references. We can resolve the address based on the section - // offset and see if we have a symbol at that address. If we do, - // use that; otherwise, puke. - if (!isExtern) - return Error("Internal relocations not supported."); - uint32_t SourceNum = RE->Word1 & 0xffffff; // 24-bit value - StringRef SourceName = SymbolNames[SourceNum]; - - // FIXME: Get the relocation addend from the target address. - - // Now store the relocation information. Associate it with the source - // symbol. - Relocations[SourceName].push_back(RelocationEntry(TargetName, - Offset, - RE->Word1, - 0 /*Addend*/)); - DEBUG(dbgs() << "Relocation at '" << TargetName << "' + " << Offset - << " from '" << SourceName << "(Word1: " - << format("0x%x", RE->Word1) << ")\n"); - } - } - return false; -} - - -bool RuntimeDyldImpl:: -loadSegment64(const MachOObject *Obj, - const MachOObject::LoadCommandInfo *SegmentLCI, - const InMemoryStruct<macho::SymtabLoadCommand> &SymtabLC) { - InMemoryStruct<macho::Segment64LoadCommand> Segment64LC; - Obj->ReadSegment64LoadCommand(*SegmentLCI, Segment64LC); - if (!Segment64LC) - return Error("unable to load segment load command"); - - for (unsigned SectNum = 0; SectNum != Segment64LC->NumSections; ++SectNum) { - InMemoryStruct<macho::Section64> Sect; - Obj->ReadSection64(*SegmentLCI, SectNum, Sect); - if (!Sect) - return Error("unable to load section: '" + Twine(SectNum) + "'"); - - // FIXME: For the time being, we're only loading text segments. - if (Sect->Flags != 0x80000400) - continue; - - // Address and names of symbols in the section. - typedef std::pair<uint64_t, StringRef> SymbolEntry; - SmallVector<SymbolEntry, 64> Symbols; - // Index of all the names, in this section or not. Used when we're - // dealing with relocation entries. - SmallVector<StringRef, 64> SymbolNames; - for (unsigned i = 0; i != SymtabLC->NumSymbolTableEntries; ++i) { - InMemoryStruct<macho::Symbol64TableEntry> STE; - Obj->ReadSymbol64TableEntry(SymtabLC->SymbolTableOffset, i, STE); - if (!STE) - return Error("unable to read symbol: '" + Twine(i) + "'"); - if (STE->SectionIndex > Segment64LC->NumSections) - return Error("invalid section index for symbol: '" + Twine(i) + "'"); - // Get the symbol name. - StringRef Name = Obj->getStringAtIndex(STE->StringIndex); - SymbolNames.push_back(Name); - - // Just skip symbols not defined in this section. - if ((unsigned)STE->SectionIndex - 1 != SectNum) - continue; - - // FIXME: Check the symbol type and flags. - if (STE->Type != 0xF) // external, defined in this section. - continue; - if (STE->Flags != 0x0) - continue; - - // Remember the symbol. - Symbols.push_back(SymbolEntry(STE->Value, Name)); - - DEBUG(dbgs() << "Function sym: '" << Name << "' @ " << - (Sect->Address + STE->Value) << "\n"); - } - // Sort the symbols by address, just in case they didn't come in that way. - array_pod_sort(Symbols.begin(), Symbols.end()); - - // If there weren't any functions (odd, but just in case...) - if (!Symbols.size()) - continue; - - // Extract the function data. - uint8_t *Base = (uint8_t*)Obj->getData(Segment64LC->FileOffset, - Segment64LC->FileSize).data(); - for (unsigned i = 0, e = Symbols.size() - 1; i != e; ++i) { - uint64_t StartOffset = Sect->Address + Symbols[i].first; - uint64_t EndOffset = Symbols[i + 1].first - 1; - DEBUG(dbgs() << "Extracting function: " << Symbols[i].second - << " from [" << StartOffset << ", " << EndOffset << "]\n"); - extractFunction(Symbols[i].second, Base + StartOffset, Base + EndOffset); - } - // The last symbol we do after since the end address is calculated - // differently because there is no next symbol to reference. - uint64_t StartOffset = Symbols[Symbols.size() - 1].first; - uint64_t EndOffset = Sect->Size - 1; - DEBUG(dbgs() << "Extracting function: " << Symbols[Symbols.size()-1].second - << " from [" << StartOffset << ", " << EndOffset << "]\n"); - extractFunction(Symbols[Symbols.size()-1].second, - Base + StartOffset, Base + EndOffset); - - // Now extract the relocation information for each function and process it. - for (unsigned j = 0; j != Sect->NumRelocationTableEntries; ++j) { - InMemoryStruct<macho::RelocationEntry> RE; - Obj->ReadRelocationEntry(Sect->RelocationTableOffset, j, RE); - if (RE->Word0 & macho::RF_Scattered) - return Error("NOT YET IMPLEMENTED: scattered relocations."); - // Word0 of the relocation is the offset into the section where the - // relocation should be applied. We need to translate that into an - // offset into a function since that's our atom. - uint32_t Offset = RE->Word0; - // Look for the function containing the address. This is used for JIT - // code, so the number of functions in section is almost always going - // to be very small (usually just one), so until we have use cases - // where that's not true, just use a trivial linear search. - unsigned SymbolNum; - unsigned NumSymbols = Symbols.size(); - assert(NumSymbols > 0 && Symbols[0].first <= Offset && - "No symbol containing relocation!"); - for (SymbolNum = 0; SymbolNum < NumSymbols - 1; ++SymbolNum) - if (Symbols[SymbolNum + 1].first > Offset) - break; - // Adjust the offset to be relative to the symbol. - Offset -= Symbols[SymbolNum].first; - // Get the name of the symbol containing the relocation. - StringRef TargetName = SymbolNames[SymbolNum]; - - bool isExtern = (RE->Word1 >> 27) & 1; - // Figure out the source symbol of the relocation. If isExtern is true, - // this relocation references the symbol table, otherwise it references - // a section in the same object, numbered from 1 through NumSections - // (SectionBases is [0, NumSections-1]). - if (!isExtern) - return Error("Internal relocations not supported."); - uint32_t SourceNum = RE->Word1 & 0xffffff; // 24-bit value - StringRef SourceName = SymbolNames[SourceNum]; - - // FIXME: Get the relocation addend from the target address. - - // Now store the relocation information. Associate it with the source - // symbol. - Relocations[SourceName].push_back(RelocationEntry(TargetName, - Offset, - RE->Word1, - 0 /*Addend*/)); - DEBUG(dbgs() << "Relocation at '" << TargetName << "' + " << Offset - << " from '" << SourceName << "(Word1: " - << format("0x%x", RE->Word1) << ")\n"); - } - } - return false; -} - -bool RuntimeDyldImpl::loadObject(MemoryBuffer *InputBuffer) { - // If the linker is in an error state, don't do anything. - if (hasError()) - return true; - // Load the Mach-O wrapper object. - std::string ErrorStr; - OwningPtr<MachOObject> Obj( - MachOObject::LoadFromBuffer(InputBuffer, &ErrorStr)); - if (!Obj) - return Error("unable to load object: '" + ErrorStr + "'"); - - // Get the CPU type information from the header. - const macho::Header &Header = Obj->getHeader(); - - // FIXME: Error checking that the loaded object is compatible with - // the system we're running on. - CPUType = Header.CPUType; - CPUSubtype = Header.CPUSubtype; - - // Validate that the load commands match what we expect. - const MachOObject::LoadCommandInfo *SegmentLCI = 0, *SymtabLCI = 0, - *DysymtabLCI = 0; - for (unsigned i = 0; i != Header.NumLoadCommands; ++i) { - const MachOObject::LoadCommandInfo &LCI = Obj->getLoadCommandInfo(i); - switch (LCI.Command.Type) { - case macho::LCT_Segment: - case macho::LCT_Segment64: - if (SegmentLCI) - return Error("unexpected input object (multiple segments)"); - SegmentLCI = &LCI; - break; - case macho::LCT_Symtab: - if (SymtabLCI) - return Error("unexpected input object (multiple symbol tables)"); - SymtabLCI = &LCI; - break; - case macho::LCT_Dysymtab: - if (DysymtabLCI) - return Error("unexpected input object (multiple symbol tables)"); - DysymtabLCI = &LCI; - break; - default: - return Error("unexpected input object (unexpected load command"); - } - } - - if (!SymtabLCI) - return Error("no symbol table found in object"); - if (!SegmentLCI) - return Error("no symbol table found in object"); - - // Read and register the symbol table data. - InMemoryStruct<macho::SymtabLoadCommand> SymtabLC; - Obj->ReadSymtabLoadCommand(*SymtabLCI, SymtabLC); - if (!SymtabLC) - return Error("unable to load symbol table load command"); - Obj->RegisterStringTable(*SymtabLC); - - // Read the dynamic link-edit information, if present (not present in static - // objects). - if (DysymtabLCI) { - InMemoryStruct<macho::DysymtabLoadCommand> DysymtabLC; - Obj->ReadDysymtabLoadCommand(*DysymtabLCI, DysymtabLC); - if (!DysymtabLC) - return Error("unable to load dynamic link-exit load command"); - - // FIXME: We don't support anything interesting yet. -// if (DysymtabLC->LocalSymbolsIndex != 0) -// return Error("NOT YET IMPLEMENTED: local symbol entries"); -// if (DysymtabLC->ExternalSymbolsIndex != 0) -// return Error("NOT YET IMPLEMENTED: non-external symbol entries"); -// if (DysymtabLC->UndefinedSymbolsIndex != SymtabLC->NumSymbolTableEntries) -// return Error("NOT YET IMPLEMENTED: undefined symbol entries"); - } - - // Load the segment load command. - if (SegmentLCI->Command.Type == macho::LCT_Segment) { - if (loadSegment32(Obj.get(), SegmentLCI, SymtabLC)) - return true; - } else { - if (loadSegment64(Obj.get(), SegmentLCI, SymtabLC)) - return true; - } - - return false; -} - // Resolve the relocations for all symbols we currently know about. void RuntimeDyldImpl::resolveRelocations() { // Just iterate over the symbols in our symbol table and assign their @@ -620,35 +51,11 @@ void RuntimeDyldImpl::resolveRelocations() { reassignSymbolAddress(i->getKey(), i->getValue()); } -// Assign an address to a symbol name and resolve all the relocations -// associated with it. -void RuntimeDyldImpl::reassignSymbolAddress(StringRef Name, uint8_t *Addr) { - // Assign the address in our symbol table. - SymbolTable[Name] = Addr; - - RelocationList &Relocs = Relocations[Name]; - for (unsigned i = 0, e = Relocs.size(); i != e; ++i) { - RelocationEntry &RE = Relocs[i]; - uint8_t *Target = SymbolTable[RE.Target] + RE.Offset; - bool isPCRel = (RE.Data >> 24) & 1; - unsigned Type = (RE.Data >> 28) & 0xf; - unsigned Size = 1 << ((RE.Data >> 25) & 3); - - DEBUG(dbgs() << "Resolving relocation at '" << RE.Target - << "' + " << RE.Offset << " (" << format("%p", Target) << ")" - << " from '" << Name << " (" << format("%p", Addr) << ")" - << "(" << (isPCRel ? "pcrel" : "absolute") - << ", type: " << Type << ", Size: " << Size << ").\n"); - - resolveRelocation(Target, Addr, isPCRel, Type, Size); - RE.isResolved = true; - } -} - //===----------------------------------------------------------------------===// // RuntimeDyld class implementation -RuntimeDyld::RuntimeDyld(RTDyldMemoryManager *MM) { - Dyld = new RuntimeDyldImpl(MM); +RuntimeDyld::RuntimeDyld(RTDyldMemoryManager *mm) { + Dyld = 0; + MM = mm; } RuntimeDyld::~RuntimeDyld() { @@ -656,6 +63,16 @@ RuntimeDyld::~RuntimeDyld() { } bool RuntimeDyld::loadObject(MemoryBuffer *InputBuffer) { + if (!Dyld) { + if (RuntimeDyldMachO::isKnownFormat(InputBuffer)) + Dyld = new RuntimeDyldMachO(MM); + else + report_fatal_error("Unknown object format!"); + } else { + if(!Dyld->isCompatibleFormat(InputBuffer)) + report_fatal_error("Incompatible object format!"); + } + return Dyld->loadObject(InputBuffer); } diff --git a/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldImpl.h b/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldImpl.h new file mode 100644 index 0000000000..bcdfb04801 --- /dev/null +++ b/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldImpl.h @@ -0,0 +1,152 @@ +//===-- RuntimeDyldImpl.h - Run-time dynamic linker for MC-JIT ------*- C++ -*-===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// Interface for the implementations of runtime dynamic linker facilities. +// +//===----------------------------------------------------------------------===// + +#ifndef LLVM_RUNTIME_DYLD_IMPL_H +#define LLVM_RUNTIME_DYLD_IMPL_H + +#include "llvm/ExecutionEngine/RuntimeDyld.h" +#include "llvm/Object/MachOObject.h" +#include "llvm/ADT/StringMap.h" +#include "llvm/ADT/Twine.h" +#include "llvm/ADT/SmallVector.h" +#include "llvm/ExecutionEngine/ExecutionEngine.h" +#include "llvm/Support/Format.h" +#include "llvm/Support/Memory.h" +#include "llvm/Support/MemoryBuffer.h" +#include "llvm/Support/system_error.h" +#include "llvm/Support/raw_ostream.h" +#include "llvm/Support/Debug.h" +#include "llvm/Support/ErrorHandling.h" + +using namespace llvm; +using namespace llvm::object; + +namespace llvm { +class RuntimeDyldImpl { +protected: + unsigned CPUType; + unsigned CPUSubtype; + + // The MemoryManager to load objects into. + RTDyldMemoryManager *MemMgr; + + // FIXME: This all assumes we're dealing with external symbols for anything + // explicitly referenced. I.e., we can index by name and things + // will work out. In practice, this may not be the case, so we + // should find a way to effectively generalize. + + // For each function, we have a MemoryBlock of it's instruction data. + StringMap<sys::MemoryBlock> Functions; + + // Master symbol table. As modules are loaded and external symbols are + // resolved, their addresses are stored here. + StringMap<uint8_t*> SymbolTable; + + bool HasError; + std::string ErrorStr; + + // Set the error state and record an error string. + bool Error(const Twine &Msg) { + ErrorStr = Msg.str(); + HasError = true; + return true; + } + + void extractFunction(StringRef Name, uint8_t *StartAddress, + uint8_t *EndAddress); + +public: + RuntimeDyldImpl(RTDyldMemoryManager *mm) : MemMgr(mm), HasError(false) {} + + virtual ~RuntimeDyldImpl(); + + virtual bool loadObject(MemoryBuffer *InputBuffer) = 0; + + void *getSymbolAddress(StringRef Name) { + // FIXME: Just look up as a function for now. Overly simple of course. + // Work in progress. + return SymbolTable.lookup(Name); + } + + void resolveRelocations(); + + virtual void reassignSymbolAddress(StringRef Name, uint8_t *Addr) = 0; + + // Is the linker in an error state? + bool hasError() { return HasError; } + + // Mark the error condition as handled and continue. + void clearError() { HasError = false; } + + // Get the error message. + StringRef getErrorString() { return ErrorStr; } + + virtual bool isCompatibleFormat(const MemoryBuffer *InputBuffer) const = 0; +}; + + +class RuntimeDyldMachO : public RuntimeDyldImpl { + + // For each symbol, keep a list of relocations based on it. Anytime + // its address is reassigned (the JIT re-compiled the function, e.g.), + // the relocations get re-resolved. + struct RelocationEntry { + std::string Target; // Object this relocation is contained in. + uint64_t Offset; // Offset into the object for the relocation. + uint32_t Data; // Second word of the raw macho relocation entry. + int64_t Addend; // Addend encoded in the instruction itself, if any. + bool isResolved; // Has this relocation been resolved previously? + + RelocationEntry(StringRef t, uint64_t offset, uint32_t data, int64_t addend) + : Target(t), Offset(offset), Data(data), Addend(addend), + isResolved(false) {} + }; + typedef SmallVector<RelocationEntry, 4> RelocationList; + StringMap<RelocationList> Relocations; + + // FIXME: Also keep a map of all the relocations contained in an object. Use + // this to dynamically answer whether all of the relocations in it have + // been resolved or not. + + bool resolveRelocation(uint8_t *Address, uint8_t *Value, bool isPCRel, + unsigned Type, unsigned Size); + bool resolveX86_64Relocation(uintptr_t Address, uintptr_t Value, bool isPCRel, + unsigned Type, unsigned Size); + bool resolveARMRelocation(uintptr_t Address, uintptr_t Value, bool isPCRel, + unsigned Type, unsigned Size); + + bool loadSegment32(const MachOObject *Obj, + const MachOObject::LoadCommandInfo *SegmentLCI, + const InMemoryStruct<macho::SymtabLoadCommand> &SymtabLC); + bool loadSegment64(const MachOObject *Obj, + const MachOObject::LoadCommandInfo *SegmentLCI, + const InMemoryStruct<macho::SymtabLoadCommand> &SymtabLC); + +public: + RuntimeDyldMachO(RTDyldMemoryManager *mm) : RuntimeDyldImpl(mm) {} + + bool loadObject(MemoryBuffer *InputBuffer); + + void reassignSymbolAddress(StringRef Name, uint8_t *Addr); + + static bool isKnownFormat(const MemoryBuffer *InputBuffer); + + bool isCompatibleFormat(const MemoryBuffer *InputBuffer) const { + return isKnownFormat(InputBuffer); + }; +}; + +} // end namespace llvm + + +#endif diff --git a/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldMachO.cpp b/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldMachO.cpp new file mode 100644 index 0000000000..623e9b2acc --- /dev/null +++ b/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldMachO.cpp @@ -0,0 +1,524 @@ +//===-- RuntimeDyldMachO.cpp - Run-time dynamic linker for MC-JIT ------*- C++ -*-===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// Implementation of the MC-JIT runtime dynamic linker. +// +//===----------------------------------------------------------------------===// + +#define DEBUG_TYPE "dyld" +#include "llvm/ADT/OwningPtr.h" +#include "llvm/ADT/StringRef.h" +#include "llvm/ADT/STLExtras.h" +#include "RuntimeDyldImpl.h" +using namespace llvm; +using namespace llvm::object; + +namespace llvm { + +bool RuntimeDyldMachO:: +resolveRelocation(uint8_t *Address, uint8_t *Value, bool isPCRel, + unsigned Type, unsigned Size) { + // This just dispatches to the proper target specific routine. + switch (CPUType) { + default: assert(0 && "Unsupported CPU type!"); + case mach::CTM_x86_64: + return resolveX86_64Relocation((uintptr_t)Address, (uintptr_t)Value, + isPCRel, Type, Size); + case mach::CTM_ARM: + return resolveARMRelocation((uintptr_t)Address, (uintptr_t)Value, + isPCRel, Type, Size); + } + llvm_unreachable(""); +} + +bool RuntimeDyldMachO:: +resolveX86_64Relocation(uintptr_t Address, uintptr_t Value, + bool isPCRel, unsigned Type, + unsigned Size) { + // If the relocation is PC-relative, the value to be encoded is the + // pointer difference. + if (isPCRel) + // FIXME: It seems this value needs to be adjusted by 4 for an effective PC + // address. Is that expected? Only for branches, perhaps? + Value -= Address + 4; + + switch(Type) { + default: + llvm_unreachable("Invalid relocation type!"); + case macho::RIT_X86_64_Unsigned: + case macho::RIT_X86_64_Branch: { + // Mask in the target value a byte at a time (we don't have an alignment + // guarantee for the target address, so this is safest). + uint8_t *p = (uint8_t*)Address; + for (unsigned i = 0; i < Size; ++i) { + *p++ = (uint8_t)Value; + Value >>= 8; + } + return false; + } + case macho::RIT_X86_64_Signed: + case macho::RIT_X86_64_GOTLoad: + case macho::RIT_X86_64_GOT: + case macho::RIT_X86_64_Subtractor: + case macho::RIT_X86_64_Signed1: + case macho::RIT_X86_64_Signed2: + case macho::RIT_X86_64_Signed4: + case macho::RIT_X86_64_TLV: + return Error("Relocation type not implemented yet!"); + } + return false; +} + +bool RuntimeDyldMachO::resolveARMRelocation(uintptr_t Address, uintptr_t Value, + bool isPCRel, unsigned Type, + unsigned Size) { + // If the relocation is PC-relative, the value to be encoded is the + // pointer difference. + if (isPCRel) { + Value -= Address; + // ARM PCRel relocations have an effective-PC offset of two instructions + // (four bytes in Thumb mode, 8 bytes in ARM mode). + // FIXME: For now, assume ARM mode. + Value -= 8; + } + + switch(Type) { + default: + llvm_unreachable("Invalid relocation type!"); + case macho::RIT_Vanilla: { + llvm_unreachable("Invalid relocation type!"); + // Mask in the target value a byte at a time (we don't have an alignment + // guarantee for the target address, so this is safest). + uint8_t *p = (uint8_t*)Address; + for (unsigned i = 0; i < Size; ++i) { + *p++ = (uint8_t)Value; + Value >>= 8; + } + break; + } + case macho::RIT_ARM_Branch24Bit: { + // Mask the value into the target address. We know instructions are + // 32-bit aligned, so we can do it all at once. + uint32_t *p = (uint32_t*)Address; + // The low two bits of the value are not encoded. + Value >>= 2; + // Mask the value to 24 bits. + Value &= 0xffffff; + // FIXME: If the destination is a Thumb function (and the instruction + // is a non-predicated BL instruction), we need to change it to a BLX + // instruction instead. + + // Insert the value into the instruction. + *p = (*p & ~0xffffff) | Value; + break; + } + case macho::RIT_ARM_ThumbBranch22Bit: + case macho::RIT_ARM_ThumbBranch32Bit: + case macho::RIT_ARM_Half: + case macho::RIT_ARM_HalfDifference: + case macho::RIT_Pair: + case macho::RIT_Difference: + case macho::RIT_ARM_LocalDifference: + case macho::RIT_ARM_PreboundLazyPointer: + return Error("Relocation type not implemented yet!"); + } + return false; +} + +bool RuntimeDyldMachO:: +loadSegment32(const MachOObject *Obj, + const MachOObject::LoadCommandInfo *SegmentLCI, + const InMemoryStruct<macho::SymtabLoadCommand> &SymtabLC) { + InMemoryStruct<macho::SegmentLoadCommand> SegmentLC; + Obj->ReadSegmentLoadCommand(*SegmentLCI, SegmentLC); + if (!SegmentLC) + return Error("unable to load segment load command"); + + for (unsigned SectNum = 0; SectNum != SegmentLC->NumSections; ++SectNum) { + InMemoryStruct<macho::Section> Sect; + Obj->ReadSection(*SegmentLCI, SectNum, Sect); + if (!Sect) + return Error("unable to load section: '" + Twine(SectNum) + "'"); + + // FIXME: For the time being, we're only loading text segments. + if (Sect->Flags != 0x80000400) + continue; + + // Address and names of symbols in the section. + typedef std::pair<uint64_t, StringRef> SymbolEntry; + SmallVector<SymbolEntry, 64> Symbols; + // Index of all the names, in this section or not. Used when we're + // dealing with relocation entries. + SmallVector<StringRef, 64> SymbolNames; + for (unsigned i = 0; i != SymtabLC->NumSymbolTableEntries; ++i) { + InMemoryStruct<macho::SymbolTableEntry> STE; + Obj->ReadSymbolTableEntry(SymtabLC->SymbolTableOffset, i, STE); + if (!STE) + return Error("unable to read symbol: '" + Twine(i) + "'"); + if (STE->SectionIndex > SegmentLC->NumSections) + return Error("invalid section index for symbol: '" + Twine(i) + "'"); + // Get the symbol name. + StringRef Name = Obj->getStringAtIndex(STE->StringIndex); + SymbolNames.push_back(Name); + + // Just skip symbols not defined in this section. + if ((unsigned)STE->SectionIndex - 1 != SectNum) + continue; + + // FIXME: Check the symbol type and flags. + if (STE->Type != 0xF) // external, defined in this section. + continue; + // Flags == 0x8 marks a thumb function for ARM, which is fine as it + // doesn't require any special handling here. + if (STE->Flags != 0x0 && STE->Flags != 0x8) + continue; + + // Remember the symbol. + Symbols.push_back(SymbolEntry(STE->Value, Name)); + + DEBUG(dbgs() << "Function sym: '" << Name << "' @ " << + (Sect->Address + STE->Value) << "\n"); + } + // Sort the symbols by address, just in case they didn't come in that way. + array_pod_sort(Symbols.begin(), Symbols.end()); + + // If there weren't any functions (odd, but just in case...) + if (!Symbols.size()) + continue; + + // Extract the function data. + uint8_t *Base = (uint8_t*)Obj->getData(SegmentLC->FileOffset, + SegmentLC->FileSize).data(); + for (unsigned i = 0, e = Symbols.size() - 1; i != e; ++i) { + uint64_t StartOffset = Sect->Address + Symbols[i].first; + uint64_t EndOffset = Symbols[i + 1].first - 1; + DEBUG(dbgs() << "Extracting function: " << Symbols[i].second + << " from [" << StartOffset << ", " << EndOffset << "]\n"); + extractFunction(Symbols[i].second, Base + StartOffset, Base + EndOffset); + } + // The last symbol we do after since the end address is calculated + // differently because there is no next symbol to reference. + uint64_t StartOffset = Symbols[Symbols.size() - 1].first; + uint64_t EndOffset = Sect->Size - 1; + DEBUG(dbgs() << "Extracting function: " << Symbols[Symbols.size()-1].second + << " from [" << StartOffset << ", " << EndOffset << "]\n"); + extractFunction(Symbols[Symbols.size()-1].second, + Base + StartOffset, Base + EndOffset); + + // Now extract the relocation information for each function and process it. + for (unsigned j = 0; j != Sect->NumRelocationTableEntries; ++j) { + InMemoryStruct<macho::RelocationEntry> RE; + Obj->ReadRelocationEntry(Sect->RelocationTableOffset, j, RE); + if (RE->Word0 & macho::RF_Scattered) + return Error("NOT YET IMPLEMENTED: scattered relocations."); + // Word0 of the relocation is the offset into the section where the + // relocation should be applied. We need to translate that into an + // offset into a function since that's our atom. + uint32_t Offset = RE->Word0; + // Look for the function containing the address. This is used for JIT + // code, so the number of functions in section is almost always going + // to be very small (usually just one), so until we have use cases + // where that's not true, just use a trivial linear search. + unsigned SymbolNum; + unsigned NumSymbols = Symbols.size(); + assert(NumSymbols > 0 && Symbols[0].first <= Offset && + "No symbol containing relocation!"); + for (SymbolNum = 0; SymbolNum < NumSymbols - 1; ++SymbolNum) + if (Symbols[SymbolNum + 1].first > Offset) + break; + // Adjust the offset to be relative to the symbol. + Offset -= Symbols[SymbolNum].first; + // Get the name of the symbol containing the relocation. + StringRef TargetName = SymbolNames[SymbolNum]; + + bool isExtern = (RE->Word1 >> 27) & 1; + // Figure out the source symbol of the relocation. If isExtern is true, + // this relocation references the symbol table, otherwise it references + // a section in the same object, numbered from 1 through NumSections + // (SectionBases is [0, NumSections-1]). + // FIXME: Some targets (ARM) use internal relocations even for + // externally visible symbols, if the definition is in the same + // file as the reference. We need to convert those back to by-name + // references. We can resolve the address based on the section + // offset and see if we have a symbol at that address. If we do, + // use that; otherwise, puke. + if (!isExtern) + return Error("Internal relocations not supported."); + uint32_t SourceNum = RE->Word1 & 0xffffff; // 24-bit value + StringRef SourceName = SymbolNames[SourceNum]; + + // FIXME: Get the relocation addend from the target address. + + // Now store the relocation information. Associate it with the source + // symbol. + Relocations[SourceName].push_back(RelocationEntry(TargetName, + Offset, + RE->Word1, + 0 /*Addend*/)); + DEBUG(dbgs() << "Relocation at '" << TargetName << "' + " << Offset + << " from '" << SourceName << "(Word1: " + << format("0x%x", RE->Word1) << ")\n"); + } + } + return false; +} + + +bool RuntimeDyldMachO:: +loadSegment64(const MachOObject *Obj, + const MachOObject::LoadCommandInfo *SegmentLCI, + const InMemoryStruct<macho::SymtabLoadCommand> &SymtabLC) { + InMemoryStruct<macho::Segment64LoadCommand> Segment64LC; + Obj->ReadSegment64LoadCommand(*SegmentLCI, Segment64LC); + if (!Segment64LC) + return Error("unable to load segment load command"); + + for (unsigned SectNum = 0; SectNum != Segment64LC->NumSections; ++SectNum) { + InMemoryStruct<macho::Section64> Sect; + Obj->ReadSection64(*SegmentLCI, SectNum, Sect); + if (!Sect) + return Error("unable to load section: '" + Twine(SectNum) + "'"); + + // FIXME: For the time being, we're only loading text segments. + if (Sect->Flags != 0x80000400) + continue; + + // Address and names of symbols in the section. + typedef std::pair<uint64_t, StringRef> SymbolEntry; + SmallVector<SymbolEntry, 64> Symbols; + // Index of all the names, in this section or not. Used when we're + // dealing with relocation entries. + SmallVector<StringRef, 64> SymbolNames; + for (unsigned i = 0; i != SymtabLC->NumSymbolTableEntries; ++i) { + InMemoryStruct<macho::Symbol64TableEntry> STE; + Obj->ReadSymbol64TableEntry(SymtabLC->SymbolTableOffset, i, STE); + if (!STE) + return Error("unable to read symbol: '" + Twine(i) + "'"); + if (STE->SectionIndex > Segment64LC->NumSections) + return Error("invalid section index for symbol: '" + Twine(i) + "'"); + // Get the symbol name. + StringRef Name = Obj->getStringAtIndex(STE->StringIndex); + SymbolNames.push_back(Name); + + // Just skip symbols not defined in this section. + if ((unsigned)STE->SectionIndex - 1 != SectNum) + continue; + + // FIXME: Check the symbol type and flags. + if (STE->Type != 0xF) // external, defined in this section. + continue; + if (STE->Flags != 0x0) + continue; + + // Remember the symbol. + Symbols.push_back(SymbolEntry(STE->Value, Name)); + + DEBUG(dbgs() << "Function sym: '" << Name << "' @ " << + (Sect->Address + STE->Value) << "\n"); + } + // Sort the symbols by address, just in case they didn't come in that way. + array_pod_sort(Symbols.begin(), Symbols.end()); + + // If there weren't any functions (odd, but just in case...) + if (!Symbols.size()) + continue; + + // Extract the function data. + uint8_t *Base = (uint8_t*)Obj->getData(Segment64LC->FileOffset, + Segment64LC->FileSize).data(); + for (unsigned i = 0, e = Symbols.size() - 1; i != e; ++i) { + uint64_t StartOffset = Sect->Address + Symbols[i].first; + uint64_t EndOffset = Symbols[i + 1].first - 1; + DEBUG(dbgs() << "Extracting function: " << Symbols[i].second + << " from [" << StartOffset << ", " << EndOffset << "]\n"); + extractFunction(Symbols[i].second, Base + StartOffset, Base + EndOffset); + } + // The last symbol we do after since the end address is calculated + // differently because there is no next symbol to reference. + uint64_t StartOffset = Symbols[Symbols.size() - 1].first; + uint64_t EndOffset = Sect->Size - 1; + DEBUG(dbgs() << "Extracting function: " << Symbols[Symbols.size()-1].second + << " from [" << StartOffset << ", " << EndOffset << "]\n"); + extractFunction(Symbols[Symbols.size()-1].second, + Base + StartOffset, Base + EndOffset); + + // Now extract the relocation information for each function and process it. + for (unsigned j = 0; j != Sect->NumRelocationTableEntries; ++j) { + InMemoryStruct<macho::RelocationEntry> RE; + Obj->ReadRelocationEntry(Sect->RelocationTableOffset, j, RE); + if (RE->Word0 & macho::RF_Scattered) + return Error("NOT YET IMPLEMENTED: scattered relocations."); + // Word0 of the relocation is the offset into the section where the + // relocation should be applied. We need to translate that into an + // offset into a function since that's our atom. + uint32_t Offset = RE->Word0; + // Look for the function containing the address. This is used for JIT + // code, so the number of functions in section is almost always going + // to be very small (usually just one), so until we have use cases + // where that's not true, just use a trivial linear search. + unsigned SymbolNum; + unsigned NumSymbols = Symbols.size(); + assert(NumSymbols > 0 && Symbols[0].first <= Offset && + "No symbol containing relocation!"); + for (SymbolNum = 0; SymbolNum < NumSymbols - 1; ++SymbolNum) + if (Symbols[SymbolNum + 1].first > Offset) + break; + // Adjust the offset to be relative to the symbol. + Offset -= Symbols[SymbolNum].first; + // Get the name of the symbol containing the relocation. + StringRef TargetName = SymbolNames[SymbolNum]; + + bool isExtern = (RE->Word1 >> 27) & 1; + // Figure out the source symbol of the relocation. If isExtern is true, + // this relocation references the symbol table, otherwise it references + // a section in the same object, numbered from 1 through NumSections + // (SectionBases is [0, NumSections-1]). + if (!isExtern) + return Error("Internal relocations not supported."); + uint32_t SourceNum = RE->Word1 & 0xffffff; // 24-bit value + StringRef SourceName = SymbolNames[SourceNum]; + + // FIXME: Get the relocation addend from the target address. + + // Now store the relocation information. Associate it with the source + // symbol. + Relocations[SourceName].push_back(RelocationEntry(TargetName, + Offset, + RE->Word1, + 0 /*Addend*/)); + DEBUG(dbgs() << "Relocation at '" << TargetName << "' + " << Offset + << " from '" << SourceName << "(Word1: " + << format("0x%x", RE->Word1) << ")\n"); + } + } + return false; +} + +bool RuntimeDyldMachO::loadObject(MemoryBuffer *InputBuffer) { + // If the linker is in an error state, don't do anything. + if (hasError()) + return true; + // Load the Mach-O wrapper object. + std::string ErrorStr; + OwningPtr<MachOObject> Obj( + MachOObject::LoadFromBuffer(InputBuffer, &ErrorStr)); + if (!Obj) + return Error("unable to load object: '" + ErrorStr + "'"); + + // Get the CPU type information from the header. + const macho::Header &Header = Obj->getHeader(); + + // FIXME: Error checking that the loaded object is compatible with + // the system we're running on. + CPUType = Header.CPUType; + CPUSubtype = Header.CPUSubtype; + + // Validate that the load commands match what we expect. + const MachOObject::LoadCommandInfo *SegmentLCI = 0, *SymtabLCI = 0, + *DysymtabLCI = 0; + for (unsigned i = 0; i != Header.NumLoadCommands; ++i) { + const MachOObject::LoadCommandInfo &LCI = Obj->getLoadCommandInfo(i); + switch (LCI.Command.Type) { + case macho::LCT_Segment: + case macho::LCT_Segment64: + if (SegmentLCI) + return Error("unexpected input object (multiple segments)"); + SegmentLCI = &LCI; + break; + case macho::LCT_Symtab: + if (SymtabLCI) + return Error("unexpected input object (multiple symbol tables)"); + SymtabLCI = &LCI; + break; + case macho::LCT_Dysymtab: + if (DysymtabLCI) + return Error("unexpected input object (multiple symbol tables)"); + DysymtabLCI = &LCI; + break; + default: + return Error("unexpected input object (unexpected load command"); + } + } + + if (!SymtabLCI) + return Error("no symbol table found in object"); + if (!SegmentLCI) + return Error("no symbol table found in object"); + + // Read and register the symbol table data. + InMemoryStruct<macho::SymtabLoadCommand> SymtabLC; + Obj->ReadSymtabLoadCommand(*SymtabLCI, SymtabLC); + if (!SymtabLC) + return Error("unable to load symbol table load command"); + Obj->RegisterStringTable(*SymtabLC); + + // Read the dynamic link-edit information, if present (not present in static + // objects). + if (DysymtabLCI) { + InMemoryStruct<macho::DysymtabLoadCommand> DysymtabLC; + Obj->ReadDysymtabLoadCommand(*DysymtabLCI, DysymtabLC); + if (!DysymtabLC) + return Error("unable to load dynamic link-exit load command"); + + // FIXME: We don't support anything interesting yet. +// if (DysymtabLC->LocalSymbolsIndex != 0) +// return Error("NOT YET IMPLEMENTED: local symbol entries"); +// if (DysymtabLC->ExternalSymbolsIndex != 0) +// return Error("NOT YET IMPLEMENTED: non-external symbol entries"); +// if (DysymtabLC->UndefinedSymbolsIndex != SymtabLC->NumSymbolTableEntries) +// return Error("NOT YET IMPLEMENTED: undefined symbol entries"); + } + + // Load the segment load command. + if (SegmentLCI->Command.Type == macho::LCT_Segment) { + if (loadSegment32(Obj.get(), SegmentLCI, SymtabLC)) + return true; + } else { + if (loadSegment64(Obj.get(), SegmentLCI, SymtabLC)) + return true; + } + + return false; +} + +// Assign an address to a symbol name and resolve all the relocations +// associated with it. +void RuntimeDyldMachO::reassignSymbolAddress(StringRef Name, uint8_t *Addr) { + // Assign the address in our symbol table. + SymbolTable[Name] = Addr; + + RelocationList &Relocs = Relocations[Name]; + for (unsigned i = 0, e = Relocs.size(); i != e; ++i) { + RelocationEntry &RE = Relocs[i]; + uint8_t *Target = SymbolTable[RE.Target] + RE.Offset; + bool isPCRel = (RE.Data >> 24) & 1; + unsigned Type = (RE.Data >> 28) & 0xf; + unsigned Size = 1 << ((RE.Data >> 25) & 3); + + DEBUG(dbgs() << "Resolving relocation at '" << RE.Target + << "' + " << RE.Offset << " (" << format("%p", Target) << ")" + << " from '" << Name << " (" << format("%p", Addr) << ")" + << "(" << (isPCRel ? "pcrel" : "absolute") + << ", type: " << Type << ", Size: " << Size << ").\n"); + + resolveRelocation(Target, Addr, isPCRel, Type, Size); + RE.isResolved = true; + } +} + +bool RuntimeDyldMachO::isKnownFormat(const MemoryBuffer *InputBuffer) { + StringRef Magic = InputBuffer->getBuffer().slice(0, 4); + if (Magic == "\xFE\xED\xFA\xCE") return true; + if (Magic == "\xCE\xFA\xED\xFE") return true; + if (Magic == "\xFE\xED\xFA\xCF") return true; + if (Magic == "\xCF\xFA\xED\xFE") return true; + return false; +} + +} // end namespace llvm |