diff options
| -rw-r--r-- | tcg/tcg.c | 233 |
1 files changed, 158 insertions, 75 deletions
@@ -2252,8 +2252,17 @@ void tcg_dump_info(FILE *f, fprintf_function cpu_fprintf) #endif #ifdef ELF_HOST_MACHINE -/* The backend should define ELF_HOST_MACHINE to indicate both what value to - put into the ELF image and to indicate support for the feature. */ +/* In order to use this feature, the backend needs to do three things: + + (1) Define ELF_HOST_MACHINE to indicate both what value to + put into the ELF image and to indicate support for the feature. + + (2) Define tcg_register_jit. This should create a buffer containing + the contents of a .debug_frame section that describes the post- + prologue unwind info for the tcg machine. + + (3) Call tcg_register_jit_int, with the constructed .debug_frame. +*/ /* Begin GDB interface. THE FOLLOWING MUST MATCH GDB DOCS. */ typedef enum { @@ -2300,96 +2309,169 @@ static int find_string(const char *strtab, const char *str) } } -static void tcg_register_jit_int(void *buf, size_t buf_size, +static void tcg_register_jit_int(void *buf_ptr, size_t buf_size, void *debug_frame, size_t debug_frame_size) { - static const char strings[64] = - "\0" - ".text\0" - ".debug_frame\0" - ".symtab\0" - ".strtab\0" - "code_gen_buffer"; + struct __attribute__((packed)) DebugInfo { + uint32_t len; + uint16_t version; + uint32_t abbrev; + uint8_t ptr_size; + uint8_t cu_die; + uint16_t cu_lang; + uintptr_t cu_low_pc; + uintptr_t cu_high_pc; + uint8_t fn_die; + char fn_name[16]; + uintptr_t fn_low_pc; + uintptr_t fn_high_pc; + uint8_t cu_eoc; + }; struct ElfImage { ElfW(Ehdr) ehdr; ElfW(Phdr) phdr; - ElfW(Shdr) shdr[5]; - ElfW(Sym) sym[1]; - char str[64]; + ElfW(Shdr) shdr[7]; + ElfW(Sym) sym[2]; + struct DebugInfo di; + uint8_t da[24]; + char str[80]; + }; + + struct ElfImage *img; + + static const struct ElfImage img_template = { + .ehdr = { + .e_ident[EI_MAG0] = ELFMAG0, + .e_ident[EI_MAG1] = ELFMAG1, + .e_ident[EI_MAG2] = ELFMAG2, + .e_ident[EI_MAG3] = ELFMAG3, + .e_ident[EI_CLASS] = ELF_CLASS, + .e_ident[EI_DATA] = ELF_DATA, + .e_ident[EI_VERSION] = EV_CURRENT, + .e_type = ET_EXEC, + .e_machine = ELF_HOST_MACHINE, + .e_version = EV_CURRENT, + .e_phoff = offsetof(struct ElfImage, phdr), + .e_shoff = offsetof(struct ElfImage, shdr), + .e_ehsize = sizeof(ElfW(Shdr)), + .e_phentsize = sizeof(ElfW(Phdr)), + .e_phnum = 1, + .e_shentsize = sizeof(ElfW(Shdr)), + .e_shnum = ARRAY_SIZE(img->shdr), + .e_shstrndx = ARRAY_SIZE(img->shdr) - 1, + }, + .phdr = { + .p_type = PT_LOAD, + .p_flags = PF_X, + }, + .shdr = { + [0] = { .sh_type = SHT_NULL }, + /* Trick: The contents of code_gen_buffer are not present in + this fake ELF file; that got allocated elsewhere. Therefore + we mark .text as SHT_NOBITS (similar to .bss) so that readers + will not look for contents. We can record any address. */ + [1] = { /* .text */ + .sh_type = SHT_NOBITS, + .sh_flags = SHF_EXECINSTR | SHF_ALLOC, + }, + [2] = { /* .debug_info */ + .sh_type = SHT_PROGBITS, + .sh_offset = offsetof(struct ElfImage, di), + .sh_size = sizeof(struct DebugInfo), + }, + [3] = { /* .debug_abbrev */ + .sh_type = SHT_PROGBITS, + .sh_offset = offsetof(struct ElfImage, da), + .sh_size = sizeof(img->da), + }, + [4] = { /* .debug_frame */ + .sh_type = SHT_PROGBITS, + .sh_offset = sizeof(struct ElfImage), + }, + [5] = { /* .symtab */ + .sh_type = SHT_SYMTAB, + .sh_offset = offsetof(struct ElfImage, sym), + .sh_size = sizeof(img->sym), + .sh_info = 1, + .sh_link = ARRAY_SIZE(img->shdr) - 1, + .sh_entsize = sizeof(ElfW(Sym)), + }, + [6] = { /* .strtab */ + .sh_type = SHT_STRTAB, + .sh_offset = offsetof(struct ElfImage, str), + .sh_size = sizeof(img->str), + } + }, + .sym = { + [1] = { /* code_gen_buffer */ + .st_info = ELF_ST_INFO(STB_GLOBAL, STT_FUNC), + .st_shndx = 1, + } + }, + .di = { + .len = sizeof(struct DebugInfo) - 4, + .version = 2, + .ptr_size = sizeof(void *), + .cu_die = 1, + .cu_lang = 0x8001, /* DW_LANG_Mips_Assembler */ + .fn_die = 2, + .fn_name = "code_gen_buffer" + }, + .da = { + 1, /* abbrev number (the cu) */ + 0x11, 1, /* DW_TAG_compile_unit, has children */ + 0x13, 0x5, /* DW_AT_language, DW_FORM_data2 */ + 0x11, 0x1, /* DW_AT_low_pc, DW_FORM_addr */ + 0x12, 0x1, /* DW_AT_high_pc, DW_FORM_addr */ + 0, 0, /* end of abbrev */ + 2, /* abbrev number (the fn) */ + 0x2e, 0, /* DW_TAG_subprogram, no children */ + 0x3, 0x8, /* DW_AT_name, DW_FORM_string */ + 0x11, 0x1, /* DW_AT_low_pc, DW_FORM_addr */ + 0x12, 0x1, /* DW_AT_high_pc, DW_FORM_addr */ + 0, 0, /* end of abbrev */ + 0 /* no more abbrev */ + }, + .str = "\0" ".text\0" ".debug_info\0" ".debug_abbrev\0" + ".debug_frame\0" ".symtab\0" ".strtab\0" "code_gen_buffer", }; /* We only need a single jit entry; statically allocate it. */ static struct jit_code_entry one_entry; + uintptr_t buf = (uintptr_t)buf_ptr; size_t img_size = sizeof(struct ElfImage) + debug_frame_size; - struct ElfImage *img = g_malloc0(img_size); - - img->ehdr.e_ident[EI_MAG0] = ELFMAG0; - img->ehdr.e_ident[EI_MAG1] = ELFMAG1; - img->ehdr.e_ident[EI_MAG2] = ELFMAG2; - img->ehdr.e_ident[EI_MAG3] = ELFMAG3; - img->ehdr.e_ident[EI_CLASS] = ELF_CLASS; - img->ehdr.e_ident[EI_DATA] = ELF_DATA; - img->ehdr.e_ident[EI_VERSION] = EV_CURRENT; - img->ehdr.e_type = ET_EXEC; - img->ehdr.e_machine = ELF_HOST_MACHINE; - img->ehdr.e_version = EV_CURRENT; - img->ehdr.e_phoff = offsetof(struct ElfImage, phdr); - img->ehdr.e_shoff = offsetof(struct ElfImage, shdr); - img->ehdr.e_ehsize = sizeof(ElfW(Shdr)); - img->ehdr.e_phentsize = sizeof(ElfW(Phdr)); - img->ehdr.e_phnum = 1; - img->ehdr.e_shentsize = sizeof(img->shdr[0]); - img->ehdr.e_shnum = ARRAY_SIZE(img->shdr); - img->ehdr.e_shstrndx = ARRAY_SIZE(img->shdr) - 1; - - img->phdr.p_type = PT_LOAD; - img->phdr.p_offset = (char *)buf - (char *)img; - img->phdr.p_vaddr = (ElfW(Addr))buf; - img->phdr.p_paddr = img->phdr.p_vaddr; - img->phdr.p_filesz = 0; - img->phdr.p_memsz = buf_size; - img->phdr.p_flags = PF_X; - memcpy(img->str, strings, sizeof(img->str)); + img = g_malloc(img_size); + *img = img_template; + memcpy(img + 1, debug_frame, debug_frame_size); - img->shdr[0].sh_type = SHT_NULL; + img->phdr.p_vaddr = buf; + img->phdr.p_paddr = buf; + img->phdr.p_memsz = buf_size; - /* Trick: The contents of code_gen_buffer are not present in this fake - ELF file; that got allocated elsewhere, discontiguously. Therefore - we mark .text as SHT_NOBITS (similar to .bss) so that readers will - not look for contents. We can record any address at will. */ img->shdr[1].sh_name = find_string(img->str, ".text"); - img->shdr[1].sh_type = SHT_NOBITS; - img->shdr[1].sh_flags = SHF_EXECINSTR | SHF_ALLOC; - img->shdr[1].sh_addr = (ElfW(Addr))buf; + img->shdr[1].sh_addr = buf; img->shdr[1].sh_size = buf_size; - img->shdr[2].sh_name = find_string(img->str, ".debug_frame"); - img->shdr[2].sh_type = SHT_PROGBITS; - img->shdr[2].sh_offset = sizeof(*img); - img->shdr[2].sh_size = debug_frame_size; - memcpy(img + 1, debug_frame, debug_frame_size); + img->shdr[2].sh_name = find_string(img->str, ".debug_info"); + img->shdr[3].sh_name = find_string(img->str, ".debug_abbrev"); + + img->shdr[4].sh_name = find_string(img->str, ".debug_frame"); + img->shdr[4].sh_size = debug_frame_size; + + img->shdr[5].sh_name = find_string(img->str, ".symtab"); + img->shdr[6].sh_name = find_string(img->str, ".strtab"); + + img->sym[1].st_name = find_string(img->str, "code_gen_buffer"); + img->sym[1].st_value = buf; + img->sym[1].st_size = buf_size; - img->shdr[3].sh_name = find_string(img->str, ".symtab"); - img->shdr[3].sh_type = SHT_SYMTAB; - img->shdr[3].sh_offset = offsetof(struct ElfImage, sym); - img->shdr[3].sh_size = sizeof(img->sym); - img->shdr[3].sh_info = ARRAY_SIZE(img->sym); - img->shdr[3].sh_link = img->ehdr.e_shstrndx; - img->shdr[3].sh_entsize = sizeof(ElfW(Sym)); - - img->shdr[4].sh_name = find_string(img->str, ".strtab"); - img->shdr[4].sh_type = SHT_STRTAB; - img->shdr[4].sh_offset = offsetof(struct ElfImage, str); - img->shdr[4].sh_size = sizeof(img->str); - - img->sym[0].st_name = find_string(img->str, "code_gen_buffer"); - img->sym[0].st_info = ELF_ST_INFO(STB_GLOBAL, STT_FUNC); - img->sym[0].st_shndx = 1; - img->sym[0].st_value = (ElfW(Addr))buf; - img->sym[0].st_size = buf_size; + img->di.cu_low_pc = buf; + img->di.cu_high_pc = buf_size; + img->di.fn_low_pc = buf; + img->di.fn_high_pc = buf_size; #ifdef DEBUG_JIT /* Enable this block to be able to debug the ELF image file creation. @@ -2397,7 +2479,7 @@ static void tcg_register_jit_int(void *buf, size_t buf_size, { FILE *f = fopen("/tmp/qemu.jit", "w+b"); if (f) { - if (fwrite(img, img_size, 1, f) != buf_size) { + if (fwrite(img, img_size, 1, f) != img_size) { /* Avoid stupid unused return value warning for fwrite. */ } fclose(f); @@ -2414,7 +2496,8 @@ static void tcg_register_jit_int(void *buf, size_t buf_size, __jit_debug_register_code(); } #else -/* No support for the feature. Provide the entry point expected by exec.c. */ +/* No support for the feature. Provide the entry point expected by exec.c, + and implement the internal function we declared earlier. */ static void tcg_register_jit_int(void *buf, size_t size, void *debug_frame, size_t debug_frame_size) |