Library-ize the dyld components of llvm-rtdyld.

Move the dynamic linking functionality of the llvm-rtdyld program into an
ExecutionEngine support library. Update llvm-rtdyld to just load an object
file into memory, use the library to process it, then run the _main()
function, if one is found.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@128031 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Jim Grosbach
2011-03-21 22:15:52 +00:00
parent b99462117e
commit 6e56331ed9
7 changed files with 402 additions and 228 deletions

View File

@ -13,6 +13,7 @@
#include "llvm/ADT/StringMap.h"
#include "llvm/ADT/OwningPtr.h"
#include "llvm/ExecutionEngine/RuntimeDyld.h"
#include "llvm/Object/MachOObject.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/ManagedStatic.h"
@ -51,157 +52,6 @@ static int Error(const Twine &Msg) {
}
/* *** */
static bool
loadSegment32(const MachOObject *Obj,
sys::MemoryBlock &Data,
const MachOObject::LoadCommandInfo *SegmentLCI,
const InMemoryStruct<macho::SymtabLoadCommand> &SymtabLC,
StringMap<void*> &SymbolTable) {
InMemoryStruct<macho::SegmentLoadCommand> Segment32LC;
Obj->ReadSegmentLoadCommand(*SegmentLCI, Segment32LC);
if (!Segment32LC)
return Error("unable to load segment load command");
// Map the segment into memory.
std::string ErrorStr;
Data = sys::Memory::AllocateRWX(Segment32LC->VMSize, 0, &ErrorStr);
if (!Data.base())
return Error("unable to allocate memory block: '" + ErrorStr + "'");
memcpy(Data.base(), Obj->getData(Segment32LC->FileOffset,
Segment32LC->FileSize).data(),
Segment32LC->FileSize);
memset((char*)Data.base() + Segment32LC->FileSize, 0,
Segment32LC->VMSize - Segment32LC->FileSize);
// Bind the section indices to address.
void **SectionBases = new void*[Segment32LC->NumSections];
for (unsigned i = 0; i != Segment32LC->NumSections; ++i) {
InMemoryStruct<macho::Section> Sect;
Obj->ReadSection(*SegmentLCI, i, 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!");
// 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::SymbolTableEntry> STE;
Obj->ReadSymbolTableEntry(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 >= 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;
// 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;
}
delete SectionBases;
return false;
}
static bool
loadSegment64(const MachOObject *Obj,
sys::MemoryBlock &Data,
const MachOObject::LoadCommandInfo *SegmentLCI,
const InMemoryStruct<macho::SymtabLoadCommand> &SymtabLC,
StringMap<void*> &SymbolTable) {
InMemoryStruct<macho::Segment64LoadCommand> Segment64LC;
Obj->ReadSegment64LoadCommand(*SegmentLCI, Segment64LC);
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) {
InMemoryStruct<macho::Section64> Sect;
Obj->ReadSection64(*SegmentLCI, i, 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!");
// 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;
}
delete SectionBases;
return false;
}
static int executeInput() {
// Load the input memory buffer.
@ -209,94 +59,28 @@ static int executeInput() {
if (error_code ec = MemoryBuffer::getFileOrSTDIN(InputFile, InputBuffer))
return Error("unable to read input: '" + ec.message() + "'");
// Load the Mach-O wrapper object.
std::string ErrorStr;
OwningPtr<MachOObject> Obj(
MachOObject::LoadFromBuffer(InputBuffer.take(), &ErrorStr));
if (!Obj)
return Error("unable to load object: '" + ErrorStr + "'");
// Instantiate a dynamic linker.
RuntimeDyld Dyld;
// 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) {
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.
sys::MemoryBlock Data;
StringMap<void*> SymbolTable;
if (SegmentLCI->Command.Type == macho::LCT_Segment) {
if (loadSegment32(Obj.get(), Data, SegmentLCI, SymtabLC, SymbolTable))
return true;
} else {
if (loadSegment64(Obj.get(), Data, SegmentLCI, SymtabLC, SymbolTable))
return true;
}
// Load the object file into it.
if (Dyld.loadObject(InputBuffer.take()))
return true;
// Get the address of "_main".
StringMap<void*>::iterator it = SymbolTable.find("_main");
if (it == SymbolTable.end())
void *MainAddress = Dyld.getSymbolAddress("_main");
if (MainAddress == 0)
return Error("no definition for '_main'");
// Invalidate the instruction cache.
sys::MemoryBlock Data = Dyld.getMemoryBlock();
sys::Memory::InvalidateInstructionCache(Data.base(), Data.size());
// Make sure the memory is executable.
std::string ErrorStr;
if (!sys::Memory::setExecutable(Data, &ErrorStr))
return Error("unable to mark function executable: '" + ErrorStr + "'");
// Dispatch to _main().
void *MainAddress = it->second;
errs() << "loaded '_main' at: " << MainAddress << "\n";
int (*Main)(int, const char**) =