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//===- RelocVisitor.h - Visitor for object file relocations -----*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file provides a wrapper around all the different types of relocations
// in different file formats, such that a client can handle them in a unified
// manner by only implementing a minimal number of functions.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_OBJECT_RELOCVISITOR_H
#define LLVM_OBJECT_RELOCVISITOR_H
#include "llvm/ADT/Triple.h"
#include "llvm/BinaryFormat/ELF.h"
#include "llvm/BinaryFormat/MachO.h"
#include "llvm/Object/COFF.h"
#include "llvm/Object/ELFObjectFile.h"
#include "llvm/Object/MachO.h"
#include "llvm/Object/ObjectFile.h"
#include "llvm/Object/Wasm.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/ErrorHandling.h"
#include <cstdint>
#include <system_error>
namespace llvm {
namespace object {
/// Base class for object file relocation visitors.
class RelocVisitor {
public:
explicit RelocVisitor(const ObjectFile &Obj) : ObjToVisit(Obj) {}
// TODO: Should handle multiple applied relocations via either passing in the
// previously computed value or just count paired relocations as a single
// visit.
uint64_t visit(uint32_t Rel, RelocationRef R, uint64_t Value = 0) {
if (isa<ELFObjectFileBase>(ObjToVisit))
return visitELF(Rel, R, Value);
if (isa<COFFObjectFile>(ObjToVisit))
return visitCOFF(Rel, R, Value);
if (isa<MachOObjectFile>(ObjToVisit))
return visitMachO(Rel, R, Value);
if (isa<WasmObjectFile>(ObjToVisit))
return visitWasm(Rel, R, Value);
HasError = true;
return 0;
}
bool error() { return HasError; }
private:
const ObjectFile &ObjToVisit;
bool HasError = false;
uint64_t visitELF(uint32_t Rel, RelocationRef R, uint64_t Value) {
if (ObjToVisit.getBytesInAddress() == 8) { // 64-bit object file
switch (ObjToVisit.getArch()) {
case Triple::x86_64:
return visitX86_64(Rel, R, Value);
case Triple::aarch64:
case Triple::aarch64_be:
return visitAarch64(Rel, R, Value);
case Triple::bpfel:
case Triple::bpfeb:
return visitBpf(Rel, R, Value);
case Triple::mips64el:
case Triple::mips64:
return visitMips64(Rel, R, Value);
case Triple::ppc64le:
case Triple::ppc64:
return visitPPC64(Rel, R, Value);
case Triple::systemz:
return visitSystemz(Rel, R, Value);
case Triple::sparcv9:
return visitSparc64(Rel, R, Value);
case Triple::amdgcn:
return visitAmdgpu(Rel, R, Value);
default:
HasError = true;
return 0;
}
}
// 32-bit object file
assert(ObjToVisit.getBytesInAddress() == 4 &&
"Invalid word size in object file");
switch (ObjToVisit.getArch()) {
case Triple::x86:
return visitX86(Rel, R, Value);
case Triple::ppc:
return visitPPC32(Rel, R, Value);
case Triple::arm:
case Triple::armeb:
return visitARM(Rel, R, Value);
case Triple::lanai:
return visitLanai(Rel, R, Value);
case Triple::mipsel:
case Triple::mips:
return visitMips32(Rel, R, Value);
case Triple::sparc:
return visitSparc32(Rel, R, Value);
case Triple::hexagon:
return visitHexagon(Rel, R, Value);
default:
HasError = true;
return 0;
}
}
int64_t getELFAddend(RelocationRef R) {
Expected<int64_t> AddendOrErr = ELFRelocationRef(R).getAddend();
handleAllErrors(AddendOrErr.takeError(), [](const ErrorInfoBase &EI) {
report_fatal_error(EI.message());
});
return *AddendOrErr;
}
uint64_t visitX86_64(uint32_t Rel, RelocationRef R, uint64_t Value) {
switch (Rel) {
case ELF::R_X86_64_NONE:
return 0;
case ELF::R_X86_64_64:
return Value + getELFAddend(R);
case ELF::R_X86_64_PC32:
return Value + getELFAddend(R) - R.getOffset();
case ELF::R_X86_64_32:
case ELF::R_X86_64_32S:
return (Value + getELFAddend(R)) & 0xFFFFFFFF;
}
HasError = true;
return 0;
}
uint64_t visitAarch64(uint32_t Rel, RelocationRef R, uint64_t Value) {
switch (Rel) {
case ELF::R_AARCH64_ABS32: {
int64_t Res = Value + getELFAddend(R);
if (Res < INT32_MIN || Res > UINT32_MAX)
HasError = true;
return static_cast<uint32_t>(Res);
}
case ELF::R_AARCH64_ABS64:
return Value + getELFAddend(R);
}
HasError = true;
return 0;
}
uint64_t visitBpf(uint32_t Rel, RelocationRef R, uint64_t Value) {
switch (Rel) {
case ELF::R_BPF_64_32:
return Value & 0xFFFFFFFF;
case ELF::R_BPF_64_64:
return Value;
}
HasError = true;
return 0;
}
uint64_t visitMips64(uint32_t Rel, RelocationRef R, uint64_t Value) {
switch (Rel) {
case ELF::R_MIPS_32:
return (Value + getELFAddend(R)) & 0xFFFFFFFF;
case ELF::R_MIPS_64:
return Value + getELFAddend(R);
case ELF::R_MIPS_TLS_DTPREL64:
return Value + getELFAddend(R) - 0x8000;
}
HasError = true;
return 0;
}
uint64_t visitPPC64(uint32_t Rel, RelocationRef R, uint64_t Value) {
switch (Rel) {
case ELF::R_PPC64_ADDR32:
return (Value + getELFAddend(R)) & 0xFFFFFFFF;
case ELF::R_PPC64_ADDR64:
return Value + getELFAddend(R);
}
HasError = true;
return 0;
}
uint64_t visitSystemz(uint32_t Rel, RelocationRef R, uint64_t Value) {
switch (Rel) {
case ELF::R_390_32: {
int64_t Res = Value + getELFAddend(R);
if (Res < INT32_MIN || Res > UINT32_MAX)
HasError = true;
return static_cast<uint32_t>(Res);
}
case ELF::R_390_64:
return Value + getELFAddend(R);
}
HasError = true;
return 0;
}
uint64_t visitSparc64(uint32_t Rel, RelocationRef R, uint64_t Value) {
switch (Rel) {
case ELF::R_SPARC_32:
case ELF::R_SPARC_64:
case ELF::R_SPARC_UA32:
case ELF::R_SPARC_UA64:
return Value + getELFAddend(R);
}
HasError = true;
return 0;
}
uint64_t visitAmdgpu(uint32_t Rel, RelocationRef R, uint64_t Value) {
switch (Rel) {
case ELF::R_AMDGPU_ABS32:
case ELF::R_AMDGPU_ABS64:
return Value + getELFAddend(R);
}
HasError = true;
return 0;
}
uint64_t visitX86(uint32_t Rel, RelocationRef R, uint64_t Value) {
switch (Rel) {
case ELF::R_386_NONE:
return 0;
case ELF::R_386_32:
return Value;
case ELF::R_386_PC32:
return Value - R.getOffset();
}
HasError = true;
return 0;
}
uint64_t visitPPC32(uint32_t Rel, RelocationRef R, uint64_t Value) {
if (Rel == ELF::R_PPC_ADDR32)
return (Value + getELFAddend(R)) & 0xFFFFFFFF;
HasError = true;
return 0;
}
uint64_t visitARM(uint32_t Rel, RelocationRef R, uint64_t Value) {
if (Rel == ELF::R_ARM_ABS32) {
if ((int64_t)Value < INT32_MIN || (int64_t)Value > UINT32_MAX)
HasError = true;
return static_cast<uint32_t>(Value);
}
HasError = true;
return 0;
}
uint64_t visitLanai(uint32_t Rel, RelocationRef R, uint64_t Value) {
if (Rel == ELF::R_LANAI_32)
return (Value + getELFAddend(R)) & 0xFFFFFFFF;
HasError = true;
return 0;
}
uint64_t visitMips32(uint32_t Rel, RelocationRef R, uint64_t Value) {
// FIXME: Take in account implicit addends to get correct results.
if (Rel == ELF::R_MIPS_32)
return Value & 0xFFFFFFFF;
if (Rel == ELF::R_MIPS_TLS_DTPREL32)
return Value & 0xFFFFFFFF;
HasError = true;
return 0;
}
uint64_t visitSparc32(uint32_t Rel, RelocationRef R, uint64_t Value) {
if (Rel == ELF::R_SPARC_32 || Rel == ELF::R_SPARC_UA32)
return Value + getELFAddend(R);
HasError = true;
return 0;
}
uint64_t visitHexagon(uint32_t Rel, RelocationRef R, uint64_t Value) {
if (Rel == ELF::R_HEX_32)
return Value + getELFAddend(R);
HasError = true;
return 0;
}
uint64_t visitCOFF(uint32_t Rel, RelocationRef R, uint64_t Value) {
switch (ObjToVisit.getArch()) {
case Triple::x86:
switch (Rel) {
case COFF::IMAGE_REL_I386_SECREL:
case COFF::IMAGE_REL_I386_DIR32:
return static_cast<uint32_t>(Value);
}
break;
case Triple::x86_64:
switch (Rel) {
case COFF::IMAGE_REL_AMD64_SECREL:
return static_cast<uint32_t>(Value);
case COFF::IMAGE_REL_AMD64_ADDR64:
return Value;
}
break;
default:
break;
}
HasError = true;
return 0;
}
uint64_t visitMachO(uint32_t Rel, RelocationRef R, uint64_t Value) {
if (ObjToVisit.getArch() == Triple::x86_64 &&
Rel == MachO::X86_64_RELOC_UNSIGNED)
return Value;
HasError = true;
return 0;
}
uint64_t visitWasm(uint32_t Rel, RelocationRef R, uint64_t Value) {
if (ObjToVisit.getArch() == Triple::wasm32) {
switch (Rel) {
case wasm::R_WEBASSEMBLY_FUNCTION_INDEX_LEB:
case wasm::R_WEBASSEMBLY_TABLE_INDEX_SLEB:
case wasm::R_WEBASSEMBLY_TABLE_INDEX_I32:
case wasm::R_WEBASSEMBLY_MEMORY_ADDR_LEB:
case wasm::R_WEBASSEMBLY_MEMORY_ADDR_SLEB:
case wasm::R_WEBASSEMBLY_MEMORY_ADDR_I32:
case wasm::R_WEBASSEMBLY_TYPE_INDEX_LEB:
case wasm::R_WEBASSEMBLY_GLOBAL_INDEX_LEB:
case wasm::R_WEBASSEMBLY_FUNCTION_OFFSET_I32:
case wasm::R_WEBASSEMBLY_SECTION_OFFSET_I32:
// For wasm section, its offset at 0 -- ignoring Value
return 0;
}
}
HasError = true;
return 0;
}
};
} // end namespace object
} // end namespace llvm
#endif // LLVM_OBJECT_RELOCVISITOR_H