133 lines
4.9 KiB
C++
133 lines
4.9 KiB
C++
#include "elna/backend/target.hpp"
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#include "elna/backend/riscv.hpp"
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#include <cstring>
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namespace elna::riscv
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{
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elfio_writer::elfio_writer(ELFIO::section *text,
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ELFIO::symbol_section_accessor symbol_accessor, ELFIO::string_section_accessor string_accessor)
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: text(text),
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symbol_accessor(symbol_accessor), string_accessor(string_accessor)
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{
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}
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std::size_t elfio_writer::sink(const std::string& label, const std::byte *data, std::size_t size)
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{
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auto offset = text->get_size();
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text->append_data(reinterpret_cast<const char *>(data), size);
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this->symbol_accessor.add_symbol(this->string_accessor, label.data(), offset, label.size(),
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ELFIO::STB_GLOBAL, ELFIO::STT_FUNC, 0, text->get_index());
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return text->get_size();
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}
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void elfio_writer::sink(const std::string& label)
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{
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this->symbol_accessor.add_symbol(this->string_accessor, "printf", 0x00000000, 0,
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ELFIO::STB_GLOBAL, ELFIO::STT_NOTYPE, 0, ELFIO::SHN_UNDEF);
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}
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std::size_t elfio_writer::size() const
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{
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return this->text->get_size();
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}
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std::ptrdiff_t lookup(ELFIO::symbol_section_accessor symbol_accessor, const std::string& label)
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{
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for (ptrdiff_t j = 0; j < symbol_accessor.get_symbols_num(); ++j)
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{
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std::string name;
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ELFIO::Elf64_Addr value;
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ELFIO::Elf_Xword size;
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unsigned char bind;
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unsigned char type;
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ELFIO::Elf_Half section_index;
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unsigned char other;
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symbol_accessor.get_symbol(j, name, value, size, bind, type, section_index, other);
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if (name == label)
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{
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return j;
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}
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}
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return -1;
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}
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void riscv32_elf(source::program *ast, source::intermediate_code_generator intermediate_code_generator,
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std::shared_ptr<source::symbol_table> table, const std::filesystem::path& out_file)
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{
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ELFIO::elfio writer;
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writer.create(ELFIO::ELFCLASS32, ELFIO::ELFDATA2LSB);
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writer.set_os_abi(ELFIO::ELFOSABI_NONE);
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writer.set_type(ELFIO::ET_REL);
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writer.set_flags(0x4); // EF_RISCV_FLOAT_ABI_DOUBLE
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writer.set_machine(ELFIO::EM_RISCV);
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// Create code section
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ELFIO::section* text_sec = writer.sections.add(".text");
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text_sec->set_type(ELFIO::SHT_PROGBITS);
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text_sec->set_flags(ELFIO::SHF_ALLOC | ELFIO::SHF_EXECINSTR);
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text_sec->set_addr_align(0x1);
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// Create string table section
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ELFIO::section* str_sec = writer.sections.add(".strtab");
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str_sec->set_type(ELFIO::SHT_STRTAB);
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// Create string table writer
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ELFIO::string_section_accessor stra(str_sec);
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// Create symbol table section
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ELFIO::section* sym_sec = writer.sections.add(".symtab");
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sym_sec->set_type(ELFIO::SHT_SYMTAB);
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sym_sec->set_info(2);
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sym_sec->set_addr_align(0x4);
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sym_sec->set_entry_size(writer.get_default_entry_size(ELFIO::SHT_SYMTAB));
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sym_sec->set_link(str_sec->get_index());
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// Create relocation table section
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ELFIO::section* rel_sec = writer.sections.add(".rel.text");
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rel_sec->set_type(ELFIO::SHT_REL);
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rel_sec->set_info(text_sec->get_index());
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rel_sec->set_addr_align(0x4);
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rel_sec->set_entry_size(writer.get_default_entry_size(ELFIO::SHT_REL));
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rel_sec->set_link(sym_sec->get_index());
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rel_sec->set_flags(ELFIO::SHF_ALLOC);
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// Create symbol relocation table writers
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ELFIO::symbol_section_accessor syma(writer, sym_sec);
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ELFIO::relocation_section_accessor rela(writer, rel_sec);
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auto _writer = std::make_shared<elfio_writer>(text_sec, syma, stra);
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auto references = generate(intermediate_code_generator, table, _writer);
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syma.arrange_local_symbols();
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for (auto& reference : references)
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{
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ELFIO::Elf_Word relocated_symbol = lookup(syma, reference.name);
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switch (reference.target)
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{
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case address_t::high20:
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rela.add_entry(reference.offset, relocated_symbol, 26 /* ELFIO::R_RISCV_HI20 */);
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// rela.add_entry(reference.offset, relocated_symbol, 51 /* ELFIO::R_RISCV_RELAX */);
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break;
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case address_t::lower12i:
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rela.add_entry(reference.offset, relocated_symbol, 27 /* ELFIO::R_RISCV_LO12_I */);
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// rela.add_entry(reference.offset, relocated_symbol, 51 /* ELFIO::R_RISCV_RELAX */);
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break;
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case address_t::text:
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rela.add_entry(reference.offset, relocated_symbol, 18 /* ELFIO::R_RISCV_CALL */);
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// rela.add_entry(reference.offset, relocated_symbol, 51 /* ELFIO::R_RISCV_RELAX */);
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break;
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}
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}
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// Create ELF object file
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writer.save(out_file);
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}
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}
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