//
//===----------------------------------------------------------------------===//
+#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"
using namespace llvm;
using namespace llvm::object;
+// Empty out-of-line virtual destructor as the key function.
+RTDyldMemoryManager::~RTDyldMemoryManager() {}
+
namespace llvm {
class RuntimeDyldImpl {
+ unsigned CPUType;
+ unsigned CPUSubtype;
+
+ // The MemoryManager to load objects into.
+ RTDyldMemoryManager *MemMgr;
+
+
+ // 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<void*> SymbolTable;
+ StringMap<uint64_t> SymbolTable;
// FIXME: Should have multiple data blocks, one for each loaded chunk of
// compiled code.
return true;
}
+ void extractFunction(StringRef Name, uint8_t *StartAddress,
+ uint8_t *EndAddress);
+ bool resolveRelocation(uint32_t BaseSection, macho::RelocationEntry RE,
+ SmallVectorImpl<void *> &SectionBases,
+ SmallVectorImpl<StringRef> &SymbolNames);
+ bool resolveX86_64Relocation(intptr_t Address, intptr_t Value, bool isPCRel,
+ unsigned Type, unsigned Size);
+ bool resolveARMRelocation(intptr_t Address, intptr_t Value, bool isPCRel,
+ unsigned Type, unsigned Size);
+
bool loadSegment32(const MachOObject *Obj,
const MachOObject::LoadCommandInfo *SegmentLCI,
const InMemoryStruct<macho::SymtabLoadCommand> &SymtabLC);
const InMemoryStruct<macho::SymtabLoadCommand> &SymtabLC);
public:
- RuntimeDyldImpl() : HasError(false) {}
+ RuntimeDyldImpl(RTDyldMemoryManager *mm) : MemMgr(mm), HasError(false) {}
bool loadObject(MemoryBuffer *InputBuffer);
- void *getSymbolAddress(StringRef Name) {
- // Use lookup() rather than [] because we don't want to add an entry
- // if there isn't one already, which the [] operator does.
- return SymbolTable.lookup(Name);
+ uint64_t getSymbolAddress(StringRef Name) {
+ // FIXME: Just look up as a function for now. Overly simple of course.
+ // Work in progress.
+ return (uint64_t)Functions.lookup(Name).base();
}
sys::MemoryBlock getMemoryBlock() { return Data; }
StringRef getErrorString() { return ErrorStr; }
};
+void RuntimeDyldImpl::extractFunction(StringRef Name, uint8_t *StartAddress,
+ uint8_t *EndAddress) {
+ // Allocate memory for the function via the memory manager.
+ uintptr_t Size = EndAddress - StartAddress + 1;
+ uint8_t *Mem = MemMgr->startFunctionBody(Name.data(), Size);
+ assert(Size >= (uint64_t)(EndAddress - StartAddress + 1) &&
+ "Memory manager failed to allocate enough memory!");
+ // Copy the function payload into the memory block.
+ memcpy(Mem, StartAddress, EndAddress - StartAddress + 1);
+ MemMgr->endFunctionBody(Name.data(), Mem, Mem + Size);
+ // Remember where we put it.
+ Functions[Name] = sys::MemoryBlock(Mem, Size);
+ DEBUG(dbgs() << " allocated to " << Mem << "\n");
+}
+bool RuntimeDyldImpl::
+resolveRelocation(uint32_t BaseSection, macho::RelocationEntry RE,
+ SmallVectorImpl<void *> &SectionBases,
+ SmallVectorImpl<StringRef> &SymbolNames) {
+ // struct relocation_info {
+ // int32_t r_address;
+ // uint32_t r_symbolnum:24,
+ // r_pcrel:1,
+ // r_length:2,
+ // r_extern:1,
+ // r_type:4;
+ // };
+ uint32_t SymbolNum = RE.Word1 & 0xffffff; // 24-bit value
+ bool isPCRel = (RE.Word1 >> 24) & 1;
+ unsigned Log2Size = (RE.Word1 >> 25) & 3;
+ bool isExtern = (RE.Word1 >> 27) & 1;
+ unsigned Type = (RE.Word1 >> 28) & 0xf;
+ if (RE.Word0 & macho::RF_Scattered)
+ return Error("NOT YET IMPLEMENTED: scattered relocations.");
+
+ // The address requiring a relocation.
+ intptr_t Address = (intptr_t)SectionBases[BaseSection] + RE.Word0;
+
+ // Figure out the target address 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]).
+ intptr_t Value;
+ if (isExtern) {
+ StringRef Name = SymbolNames[SymbolNum];
+ if (SymbolTable.lookup(Name)) {
+ // The symbol is in our symbol table, so we can resolve it directly.
+ Value = (intptr_t)SymbolTable[Name];
+ } else {
+ return Error("NOT YET IMPLEMENTED: relocations to pre-compiled code.");
+ }
+ DEBUG(dbgs() << "Resolve relocation(" << Type << ") from '" << Name
+ << "' to " << format("0x%x", Address) << ".\n");
+ } else {
+ // For non-external relocations, the SymbolNum is actual a section number
+ // as described above.
+ Value = (intptr_t)SectionBases[SymbolNum - 1];
+ }
+
+ unsigned Size = 1 << Log2Size;
+ switch (CPUType) {
+ default: assert(0 && "Unsupported CPU type!");
+ case mach::CTM_x86_64:
+ return resolveX86_64Relocation(Address, Value, isPCRel, Type, Size);
+ case mach::CTM_ARM:
+ return resolveARMRelocation(Address, Value, isPCRel, Type, Size);
+ }
+ llvm_unreachable("");
+}
+
+bool RuntimeDyldImpl::resolveX86_64Relocation(intptr_t Address, intptr_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(intptr_t Address, intptr_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:
+ 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_Pair:
+ case macho::RIT_Difference:
+ case macho::RIT_ARM_LocalDifference:
+ case macho::RIT_ARM_PreboundLazyPointer:
+ 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:
+ return Error("Relocation type not implemented yet!");
+ }
+ return false;
+}
bool RuntimeDyldImpl::
loadSegment32(const MachOObject *Obj,
memset((char*)Data.base() + Segment32LC->FileSize, 0,
Segment32LC->VMSize - Segment32LC->FileSize);
- // Bind the section indices to address.
- void **SectionBases = new void*[Segment32LC->NumSections];
+ // Bind the section indices to addresses and record the relocations we
+ // need to resolve.
+ typedef std::pair<uint32_t, macho::RelocationEntry> RelocationMap;
+ SmallVector<RelocationMap, 64> Relocations;
+
+ SmallVector<void *, 16> SectionBases;
for (unsigned i = 0; i != Segment32LC->NumSections; ++i) {
InMemoryStruct<macho::Section> Sect;
Obj->ReadSection(*SegmentLCI, i, Sect);
- if (!Sect)
+ if (!Sect)
return Error("unable to load section: '" + Twine(i) + "'");
- // FIXME: We don't support relocations yet.
- if (Sect->NumRelocationTableEntries != 0)
- return Error("not yet implemented: relocations!");
+ // Remember any relocations the section has so we can resolve them later.
+ for (unsigned j = 0; j != Sect->NumRelocationTableEntries; ++j) {
+ InMemoryStruct<macho::RelocationEntry> RE;
+ Obj->ReadRelocationEntry(Sect->RelocationTableOffset, j, RE);
+ Relocations.push_back(RelocationMap(j, *RE));
+ }
// FIXME: Improve check.
- if (Sect->Flags != 0x80000400)
- return Error("unsupported section type!");
+// if (Sect->Flags != 0x80000400)
+// return Error("unsupported section type!");
- SectionBases[i] = (char*) Data.base() + Sect->Address;
+ SectionBases.push_back((char*) Data.base() + Sect->Address);
}
- // Bind all the symbols to address.
+ // Bind all the symbols to address. Keep a record of the names for use
+ // by relocation resolution.
+ 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) + "'");
+ // Get the symbol name.
+ StringRef Name = Obj->getStringAtIndex(STE->StringIndex);
+ SymbolNames.push_back(Name);
+
+ // Just skip undefined symbols. They'll be loaded from whatever
+ // module they come from (or system dylib) when we resolve relocations
+ // involving them.
if (STE->SectionIndex == 0)
- return Error("unexpected undefined symbol!");
+ continue;
unsigned Index = STE->SectionIndex - 1;
if (Index >= Segment32LC->NumSections)
return Error("invalid section index for symbol: '" + Twine() + "'");
- // Get the symbol name.
- StringRef Name = Obj->getStringAtIndex(STE->StringIndex);
-
// Get the section base address.
void *SectionBase = SectionBases[Index];
// Get the symbol address.
- void *Address = (char*) SectionBase + STE->Value;
+ uint64_t Address = (uint64_t)SectionBase + STE->Value;
// FIXME: Check the symbol type and flags.
if (STE->Type != 0xF)
if (STE->Flags != 0x0)
return Error("unexpected symbol type!");
+ DEBUG(dbgs() << "Symbol: '" << Name << "' @ " << Address << "\n");
+
SymbolTable[Name] = Address;
}
+ // Now resolve any relocations.
+ for (unsigned i = 0, e = Relocations.size(); i != e; ++i) {
+ if (resolveRelocation(Relocations[i].first, Relocations[i].second,
+ SectionBases, SymbolNames))
+ return true;
+ }
+
// We've loaded the section; now mark the functions in it as executable.
- // FIXME: We really should use the JITMemoryManager for this.
+ // FIXME: We really should use the MemoryManager for this.
sys::Memory::setRangeExecutable(Data.base(), Data.size());
- delete SectionBases;
return false;
}
if (!Segment64LC)
return Error("unable to load segment load command");
- // Map the segment into memory.
- std::string ErrorStr;
- Data = sys::Memory::AllocateRWX(Segment64LC->VMSize, 0, &ErrorStr);
- if (!Data.base())
- return Error("unable to allocate memory block: '" + ErrorStr + "'");
- memcpy(Data.base(), Obj->getData(Segment64LC->FileOffset,
- Segment64LC->FileSize).data(),
- Segment64LC->FileSize);
- memset((char*)Data.base() + Segment64LC->FileSize, 0,
- Segment64LC->VMSize - Segment64LC->FileSize);
-
- // Bind the section indices to address.
- void **SectionBases = new void*[Segment64LC->NumSections];
- for (unsigned i = 0; i != Segment64LC->NumSections; ++i) {
+ for (unsigned SectNum = 0; SectNum != Segment64LC->NumSections; ++SectNum) {
InMemoryStruct<macho::Section64> Sect;
- Obj->ReadSection64(*SegmentLCI, i, Sect);
+ Obj->ReadSection64(*SegmentLCI, SectNum, Sect);
if (!Sect)
- return Error("unable to load section: '" + Twine(i) + "'");
-
- // FIXME: We don't support relocations yet.
- if (Sect->NumRelocationTableEntries != 0)
- return Error("not yet implemented: relocations!");
+ return Error("unable to load section: '" + Twine(SectNum) + "'");
// FIXME: Improve check.
if (Sect->Flags != 0x80000400)
return Error("unsupported section type!");
- SectionBases[i] = (char*) Data.base() + Sect->Address;
- }
-
- // Bind all the symbols to address.
- 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 == 0)
- return Error("unexpected undefined symbol!");
-
- unsigned Index = STE->SectionIndex - 1;
- if (Index >= Segment64LC->NumSections)
- return Error("invalid section index for symbol: '" + Twine() + "'");
-
- // Get the symbol name.
- StringRef Name = Obj->getStringAtIndex(STE->StringIndex);
-
- // Get the section base address.
- void *SectionBase = SectionBases[Index];
-
- // Get the symbol address.
- void *Address = (char*) SectionBase + STE->Value;
-
- // FIXME: Check the symbol type and flags.
- if (STE->Type != 0xF)
- return Error("unexpected symbol type!");
- if (STE->Flags != 0x0)
- return Error("unexpected symbol type!");
-
- SymbolTable[Name] = Address;
+ // Address and names of symbols in the section.
+ typedef std::pair<uint64_t, StringRef> SymbolEntry;
+ SmallVector<SymbolEntry, 64> Symbols;
+ 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() + "'");
+
+ // Just skip symbols not defined in this section.
+ if (STE->SectionIndex - 1 != SectNum)
+ continue;
+
+ // Get the symbol name.
+ StringRef Name = Obj->getStringAtIndex(STE->StringIndex);
+
+ // FIXME: Check the symbol type and flags.
+ if (STE->Type != 0xF) // external, defined in this section.
+ return Error("unexpected symbol type!");
+ if (STE->Flags != 0x0)
+ return Error("unexpected symbol type!");
+
+ uint64_t BaseAddress = Sect->Address;
+ uint64_t Address = BaseAddress + STE->Value;
+
+ // Remember the symbol.
+ Symbols.push_back(SymbolEntry(Address, Name));
+
+ DEBUG(dbgs() << "Function sym: '" << Name << "' @ " << Address << "\n");
+ }
+ // Sort the symbols by address, just in case they didn't come in that
+ // way.
+ array_pod_sort(Symbols.begin(), Symbols.end());
+
+ // 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 = 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);
}
- // We've loaded the section; now mark the functions in it as executable.
- // FIXME: We really should use the JITMemoryManager for this.
- sys::Memory::setRangeExecutable(Data.base(), Data.size());
-
- delete SectionBases;
return false;
}
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 != Obj->getHeader().NumLoadCommands; ++i) {
+ for (unsigned i = 0; i != Header.NumLoadCommands; ++i) {
const MachOObject::LoadCommandInfo &LCI = Obj->getLoadCommandInfo(i);
switch (LCI.Command.Type) {
case macho::LCT_Segment:
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");
+// 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.
//===----------------------------------------------------------------------===//
// RuntimeDyld class implementation
-RuntimeDyld::RuntimeDyld() {
- Dyld = new RuntimeDyldImpl;
+RuntimeDyld::RuntimeDyld(RTDyldMemoryManager *MM) {
+ Dyld = new RuntimeDyldImpl(MM);
}
RuntimeDyld::~RuntimeDyld() {
return Dyld->loadObject(InputBuffer);
}
-void *RuntimeDyld::getSymbolAddress(StringRef Name) {
+uint64_t RuntimeDyld::getSymbolAddress(StringRef Name) {
return Dyld->getSymbolAddress(Name);
}
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