Add to RuntimeDyld support different object formats
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@135037 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldMachO.cpp b/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldMachO.cpp
new file mode 100644
index 0000000..623e9b2
--- /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