0ad562b48b
This patch is the initial support, it implements translation from object file to JIT link graph, and very few relocations were supported. Currently, the test file ELF_pc_indirect.s is passed, the HelloWorld program(compiled with mno-relax flag) can be linked correctly and run on instruction emulator correctly. In the downstream implementation, I have implemented the GOT, PLT function, and EHFrame and some optimization will be implement soon. I will organize the code in to patches, then gradually send it to upstream. Differential Revision: https://reviews.llvm.org/D105429
99 lines
2.9 KiB
C++
99 lines
2.9 KiB
C++
//===-------------- ELF.cpp - JIT linker function for ELF -------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// ELF jit-link function.
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/ExecutionEngine/JITLink/ELF.h"
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#include "llvm/BinaryFormat/ELF.h"
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#include "llvm/ExecutionEngine/JITLink/ELF_riscv.h"
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#include "llvm/ExecutionEngine/JITLink/ELF_x86_64.h"
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#include "llvm/Object/ELF.h"
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#include "llvm/Support/Endian.h"
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#include "llvm/Support/Format.h"
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#include "llvm/Support/MemoryBuffer.h"
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#include <cstring>
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using namespace llvm;
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#define DEBUG_TYPE "jitlink"
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namespace llvm {
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namespace jitlink {
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Expected<uint16_t> readTargetMachineArch(StringRef Buffer) {
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const char *Data = Buffer.data();
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if (Data[ELF::EI_DATA] == ELF::ELFDATA2LSB) {
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if (Data[ELF::EI_CLASS] == ELF::ELFCLASS64) {
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if (auto File = llvm::object::ELF64LEFile::create(Buffer)) {
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return File->getHeader().e_machine;
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} else {
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return File.takeError();
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}
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} else if (Data[ELF::EI_CLASS] == ELF::ELFCLASS32) {
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if (auto File = llvm::object::ELF32LEFile::create(Buffer)) {
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return File->getHeader().e_machine;
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} else {
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return File.takeError();
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}
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}
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}
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return ELF::EM_NONE;
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}
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Expected<std::unique_ptr<LinkGraph>>
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createLinkGraphFromELFObject(MemoryBufferRef ObjectBuffer) {
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StringRef Buffer = ObjectBuffer.getBuffer();
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if (Buffer.size() < ELF::EI_MAG3 + 1)
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return make_error<JITLinkError>("Truncated ELF buffer");
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if (memcmp(Buffer.data(), ELF::ElfMagic, strlen(ELF::ElfMagic)) != 0)
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return make_error<JITLinkError>("ELF magic not valid");
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Expected<uint16_t> TargetMachineArch = readTargetMachineArch(Buffer);
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if (!TargetMachineArch)
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return TargetMachineArch.takeError();
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switch (*TargetMachineArch) {
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case ELF::EM_RISCV:
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return createLinkGraphFromELFObject_riscv(ObjectBuffer);
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case ELF::EM_X86_64:
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return createLinkGraphFromELFObject_x86_64(ObjectBuffer);
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default:
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return make_error<JITLinkError>(
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"Unsupported target machine architecture in ELF object " +
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ObjectBuffer.getBufferIdentifier());
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}
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}
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void link_ELF(std::unique_ptr<LinkGraph> G,
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std::unique_ptr<JITLinkContext> Ctx) {
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switch (G->getTargetTriple().getArch()) {
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case Triple::riscv32:
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case Triple::riscv64:
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link_ELF_riscv(std::move(G), std::move(Ctx));
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return;
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case Triple::x86_64:
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link_ELF_x86_64(std::move(G), std::move(Ctx));
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return;
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default:
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Ctx->notifyFailed(make_error<JITLinkError>(
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"Unsupported target machine architecture in ELF link graph " +
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G->getName()));
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return;
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}
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}
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} // end namespace jitlink
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} // end namespace llvm
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