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//===--- RuntimeDyldCOFFI386.h --- COFF/X86_64 specific code ---*- C++ --*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// COFF x86 support for MC-JIT runtime dynamic linker.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_LIB_EXECUTIONENGINE_RUNTIMEDYLD_TARGETS_RUNTIMEDYLDCOFFI386_H
#define LLVM_LIB_EXECUTIONENGINE_RUNTIMEDYLD_TARGETS_RUNTIMEDYLDCOFFI386_H
#include "../RuntimeDyldCOFF.h"
#include "llvm/BinaryFormat/COFF.h"
#include "llvm/Object/COFF.h"
#define DEBUG_TYPE "dyld"
namespace llvm {
class RuntimeDyldCOFFI386 : public RuntimeDyldCOFF {
public:
RuntimeDyldCOFFI386(RuntimeDyld::MemoryManager &MM,
JITSymbolResolver &Resolver)
: RuntimeDyldCOFF(MM, Resolver, 4, COFF::IMAGE_REL_I386_DIR32) {}
unsigned getMaxStubSize() const override {
return 8; // 2-byte jmp instruction + 32-bit relative address + 2 byte pad
}
Align getStubAlignment() override { return Align(1); }
Expected<object::relocation_iterator>
processRelocationRef(unsigned SectionID,
object::relocation_iterator RelI,
const object::ObjectFile &Obj,
ObjSectionToIDMap &ObjSectionToID,
StubMap &Stubs) override {
auto Symbol = RelI->getSymbol();
if (Symbol == Obj.symbol_end())
report_fatal_error("Unknown symbol in relocation");
Expected<StringRef> TargetNameOrErr = Symbol->getName();
if (!TargetNameOrErr)
return TargetNameOrErr.takeError();
StringRef TargetName = *TargetNameOrErr;
auto SectionOrErr = Symbol->getSection();
if (!SectionOrErr)
return SectionOrErr.takeError();
auto Section = *SectionOrErr;
bool IsExtern = Section == Obj.section_end();
uint64_t RelType = RelI->getType();
uint64_t Offset = RelI->getOffset();
unsigned TargetSectionID = -1;
uint64_t TargetOffset = -1;
if (TargetName.startswith(getImportSymbolPrefix())) {
TargetSectionID = SectionID;
TargetOffset = getDLLImportOffset(SectionID, Stubs, TargetName, true);
TargetName = StringRef();
IsExtern = false;
} else if (!IsExtern) {
if (auto TargetSectionIDOrErr = findOrEmitSection(
Obj, *Section, Section->isText(), ObjSectionToID))
TargetSectionID = *TargetSectionIDOrErr;
else
return TargetSectionIDOrErr.takeError();
if (RelType != COFF::IMAGE_REL_I386_SECTION)
TargetOffset = getSymbolOffset(*Symbol);
}
// Determine the Addend used to adjust the relocation value.
uint64_t Addend = 0;
SectionEntry &AddendSection = Sections[SectionID];
uintptr_t ObjTarget = AddendSection.getObjAddress() + Offset;
uint8_t *Displacement = (uint8_t *)ObjTarget;
switch (RelType) {
case COFF::IMAGE_REL_I386_DIR32:
case COFF::IMAGE_REL_I386_DIR32NB:
case COFF::IMAGE_REL_I386_SECREL:
case COFF::IMAGE_REL_I386_REL32: {
Addend = readBytesUnaligned(Displacement, 4);
break;
}
default:
break;
}
#if !defined(NDEBUG)
SmallString<32> RelTypeName;
RelI->getTypeName(RelTypeName);
#endif
LLVM_DEBUG(dbgs() << "\t\tIn Section " << SectionID << " Offset " << Offset
<< " RelType: " << RelTypeName << " TargetName: "
<< TargetName << " Addend " << Addend << "\n");
if (IsExtern) {
RelocationEntry RE(SectionID, Offset, RelType, 0, -1, 0, 0, 0, false, 0);
addRelocationForSymbol(RE, TargetName);
} else {
switch (RelType) {
case COFF::IMAGE_REL_I386_ABSOLUTE:
// This relocation is ignored.
break;
case COFF::IMAGE_REL_I386_DIR32:
case COFF::IMAGE_REL_I386_DIR32NB:
case COFF::IMAGE_REL_I386_REL32: {
RelocationEntry RE =
RelocationEntry(SectionID, Offset, RelType, Addend, TargetSectionID,
TargetOffset, 0, 0, false, 0);
addRelocationForSection(RE, TargetSectionID);
break;
}
case COFF::IMAGE_REL_I386_SECTION: {
RelocationEntry RE =
RelocationEntry(TargetSectionID, Offset, RelType, 0);
addRelocationForSection(RE, TargetSectionID);
break;
}
case COFF::IMAGE_REL_I386_SECREL: {
RelocationEntry RE =
RelocationEntry(SectionID, Offset, RelType, TargetOffset + Addend);
addRelocationForSection(RE, TargetSectionID);
break;
}
default:
llvm_unreachable("unsupported relocation type");
}
}
return ++RelI;
}
void resolveRelocation(const RelocationEntry &RE, uint64_t Value) override {
const auto Section = Sections[RE.SectionID];
uint8_t *Target = Section.getAddressWithOffset(RE.Offset);
switch (RE.RelType) {
case COFF::IMAGE_REL_I386_ABSOLUTE:
// This relocation is ignored.
break;
case COFF::IMAGE_REL_I386_DIR32: {
// The target's 32-bit VA.
uint64_t Result =
RE.Sections.SectionA == static_cast<uint32_t>(-1)
? Value
: Sections[RE.Sections.SectionA].getLoadAddressWithOffset(
RE.Addend);
assert(Result <= UINT32_MAX && "relocation overflow");
LLVM_DEBUG(dbgs() << "\t\tOffset: " << RE.Offset
<< " RelType: IMAGE_REL_I386_DIR32"
<< " TargetSection: " << RE.Sections.SectionA
<< " Value: " << format("0x%08" PRIx32, Result)
<< '\n');
writeBytesUnaligned(Result, Target, 4);
break;
}
case COFF::IMAGE_REL_I386_DIR32NB: {
// The target's 32-bit RVA.
// NOTE: use Section[0].getLoadAddress() as an approximation of ImageBase
uint64_t Result =
Sections[RE.Sections.SectionA].getLoadAddressWithOffset(RE.Addend) -
Sections[0].getLoadAddress();
assert(Result <= UINT32_MAX && "relocation overflow");
LLVM_DEBUG(dbgs() << "\t\tOffset: " << RE.Offset
<< " RelType: IMAGE_REL_I386_DIR32NB"
<< " TargetSection: " << RE.Sections.SectionA
<< " Value: " << format("0x%08" PRIx32, Result)
<< '\n');
writeBytesUnaligned(Result, Target, 4);
break;
}
case COFF::IMAGE_REL_I386_REL32: {
// 32-bit relative displacement to the target.
uint64_t Result = RE.Sections.SectionA == static_cast<uint32_t>(-1)
? Value
: Sections[RE.Sections.SectionA].getLoadAddress();
Result = Result - Section.getLoadAddress() + RE.Addend - 4 - RE.Offset;
assert(static_cast<int64_t>(Result) <= INT32_MAX &&
"relocation overflow");
assert(static_cast<int64_t>(Result) >= INT32_MIN &&
"relocation underflow");
LLVM_DEBUG(dbgs() << "\t\tOffset: " << RE.Offset
<< " RelType: IMAGE_REL_I386_REL32"
<< " TargetSection: " << RE.Sections.SectionA
<< " Value: " << format("0x%08" PRIx32, Result)
<< '\n');
writeBytesUnaligned(Result, Target, 4);
break;
}
case COFF::IMAGE_REL_I386_SECTION:
// 16-bit section index of the section that contains the target.
assert(static_cast<uint32_t>(RE.SectionID) <= UINT16_MAX &&
"relocation overflow");
LLVM_DEBUG(dbgs() << "\t\tOffset: " << RE.Offset
<< " RelType: IMAGE_REL_I386_SECTION Value: "
<< RE.SectionID << '\n');
writeBytesUnaligned(RE.SectionID, Target, 2);
break;
case COFF::IMAGE_REL_I386_SECREL:
// 32-bit offset of the target from the beginning of its section.
assert(static_cast<uint64_t>(RE.Addend) <= UINT32_MAX &&
"relocation overflow");
LLVM_DEBUG(dbgs() << "\t\tOffset: " << RE.Offset
<< " RelType: IMAGE_REL_I386_SECREL Value: "
<< RE.Addend << '\n');
writeBytesUnaligned(RE.Addend, Target, 4);
break;
default:
llvm_unreachable("unsupported relocation type");
}
}
void registerEHFrames() override {}
};
}
#endif
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