//===-- RuntimeDyldCOFFX86_64.h --- COFF/X86_64 specific code ---*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// COFF x86_x64 support for MC-JIT runtime dynamic linker.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_LIB_EXECUTIONENGINE_RUNTIMEDYLD_TARGETS_RUNTIMEDYLDCOFF86_64_H
#define LLVM_LIB_EXECUTIONENGINE_RUNTIMEDYLD_TARGETS_RUNTIMEDYLDCOFF86_64_H
#include "llvm/Object/COFF.h"
#include "llvm/Support/COFF.h"
#include "../RuntimeDyldCOFF.h"
#define DEBUG_TYPE "dyld"
namespace llvm {
class RuntimeDyldCOFFX86_64 : public RuntimeDyldCOFF {
private:
// When a module is loaded we save the SectionID of the unwind
// sections in a table until we receive a request to register all
// unregisteredEH frame sections with the memory manager.
SmallVector<SID, 2> UnregisteredEHFrameSections;
SmallVector<SID, 2> RegisteredEHFrameSections;
public:
RuntimeDyldCOFFX86_64(RuntimeDyld::MemoryManager &MM,
RuntimeDyld::SymbolResolver &Resolver)
: RuntimeDyldCOFF(MM, Resolver) {}
unsigned getMaxStubSize() override {
return 6; // 2-byte jmp instruction + 32-bit relative address
}
// The target location for the relocation is described by RE.SectionID and
// RE.Offset. RE.SectionID can be used to find the SectionEntry. Each
// SectionEntry has three members describing its location.
// SectionEntry::Address is the address at which the section has been loaded
// into memory in the current (host) process. SectionEntry::LoadAddress is
// the address that the section will have in the target process.
// SectionEntry::ObjAddress is the address of the bits for this section in the
// original emitted object image (also in the current address space).
//
// Relocations will be applied as if the section were loaded at
// SectionEntry::LoadAddress, but they will be applied at an address based
// on SectionEntry::Address. SectionEntry::ObjAddress will be used to refer
// to Target memory contents if they are required for value calculations.
//
// The Value parameter here is the load address of the symbol for the
// relocation to be applied. For relocations which refer to symbols in the
// current object Value will be the LoadAddress of the section in which
// the symbol resides (RE.Addend provides additional information about the
// symbol location). For external symbols, Value will be the address of the
// symbol in the target address space.
void resolveRelocation(const RelocationEntry &RE, uint64_t Value) override {
const SectionEntry &Section = Sections[RE.SectionID];
uint8_t *Target = Section.getAddressWithOffset(RE.Offset);
switch (RE.RelType) {
case COFF::IMAGE_REL_AMD64_REL32:
case COFF::IMAGE_REL_AMD64_REL32_1:
case COFF::IMAGE_REL_AMD64_REL32_2:
case COFF::IMAGE_REL_AMD64_REL32_3:
case COFF::IMAGE_REL_AMD64_REL32_4:
case COFF::IMAGE_REL_AMD64_REL32_5: {
uint64_t FinalAddress = Section.getLoadAddressWithOffset(RE.Offset);
// Delta is the distance from the start of the reloc to the end of the
// instruction with the reloc.
uint64_t Delta = 4 + (RE.RelType - COFF::IMAGE_REL_AMD64_REL32);
Value -= FinalAddress + Delta;
uint64_t Result = Value + RE.Addend;
assert(((int64_t)Result <= INT32_MAX) && "Relocation overflow");
assert(((int64_t)Result >= INT32_MIN) && "Relocation underflow");
writeBytesUnaligned(Result, Target, 4);
break;
}
case COFF::IMAGE_REL_AMD64_ADDR32NB: {
// Note ADDR32NB requires a well-established notion of
// image base. This address must be less than or equal
// to every section's load address, and all sections must be
// within a 32 bit offset from the base.
//
// For now we just set these to zero.
writeBytesUnaligned(0, Target, 4);
break;
}
case COFF::IMAGE_REL_AMD64_ADDR64: {
writeBytesUnaligned(Value + RE.Addend, Target, 8);
break;
}
default:
llvm_unreachable("Relocation type not implemented yet!");
break;
}
}
relocation_iterator processRelocationRef(unsigned SectionID,
relocation_iterator RelI,
const ObjectFile &Obj,
ObjSectionToIDMap &ObjSectionToID,
StubMap &Stubs) override {
// If possible, find the symbol referred to in the relocation,
// and the section that contains it.
symbol_iterator Symbol = RelI->getSymbol();
if (Symbol == Obj.symbol_end())
report_fatal_error("Unknown symbol in relocation");
section_iterator SecI = *Symbol->getSection();
// If there is no section, this must be an external reference.
const bool IsExtern = SecI == Obj.section_end();
// Determine the Addend used to adjust the relocation value.
uint64_t RelType = RelI->getType();
uint64_t Offset = RelI->getOffset();
uint64_t Addend = 0;
SectionEntry &Section = Sections[SectionID];
uintptr_t ObjTarget = Section.getObjAddress() + Offset;
switch (RelType) {
case COFF::IMAGE_REL_AMD64_REL32:
case COFF::IMAGE_REL_AMD64_REL32_1:
case COFF::IMAGE_REL_AMD64_REL32_2:
case COFF::IMAGE_REL_AMD64_REL32_3:
case COFF::IMAGE_REL_AMD64_REL32_4:
case COFF::IMAGE_REL_AMD64_REL32_5:
case COFF::IMAGE_REL_AMD64_ADDR32NB: {
uint8_t *Displacement = (uint8_t *)ObjTarget;
Addend = readBytesUnaligned(Displacement, 4);
break;
}
case COFF::IMAGE_REL_AMD64_ADDR64: {
uint8_t *Displacement = (uint8_t *)ObjTarget;
Addend = readBytesUnaligned(Displacement, 8);
break;
}
default:
break;
}
ErrorOr<StringRef> TargetNameOrErr = Symbol->getName();
if (std::error_code EC = TargetNameOrErr.getError())
report_fatal_error(EC.message());
StringRef TargetName = *TargetNameOrErr;
DEBUG(dbgs() << "\t\tIn Section " << SectionID << " Offset " << Offset
<< " RelType: " << RelType << " TargetName: " << TargetName
<< " Addend " << Addend << "\n");
if (IsExtern) {
RelocationEntry RE(SectionID, Offset, RelType, Addend);
addRelocationForSymbol(RE, TargetName);
} else {
bool IsCode = SecI->isText();
unsigned TargetSectionID =
findOrEmitSection(Obj, *SecI, IsCode, ObjSectionToID);
uint64_t TargetOffset = getSymbolOffset(*Symbol);
RelocationEntry RE(SectionID, Offset, RelType, TargetOffset + Addend);
addRelocationForSection(RE, TargetSectionID);
}
return ++RelI;
}
unsigned getStubAlignment() override { return 1; }
void registerEHFrames() override {
for (auto const &EHFrameSID : UnregisteredEHFrameSections) {
uint8_t *EHFrameAddr = Sections[EHFrameSID].getAddress();
uint64_t EHFrameLoadAddr = Sections[EHFrameSID].getLoadAddress();
size_t EHFrameSize = Sections[EHFrameSID].getSize();
MemMgr.registerEHFrames(EHFrameAddr, EHFrameLoadAddr, EHFrameSize);
RegisteredEHFrameSections.push_back(EHFrameSID);
}
UnregisteredEHFrameSections.clear();
}
void deregisterEHFrames() override {
// Stub
}
void finalizeLoad(const ObjectFile &Obj,
ObjSectionToIDMap &SectionMap) override {
// Look for and record the EH frame section IDs.
for (const auto &SectionPair : SectionMap) {
const SectionRef &Section = SectionPair.first;
StringRef Name;
Check(Section.getName(Name));
// Note unwind info is split across .pdata and .xdata, so this
// may not be sufficiently general for all users.
if (Name == ".xdata") {
UnregisteredEHFrameSections.push_back(SectionPair.second);
}
}
}
};
} // end namespace llvm
#undef DEBUG_TYPE
#endif