diff options
| -rw-r--r-- | tccelf.c | 114 |
1 files changed, 68 insertions, 46 deletions
@@ -433,7 +433,7 @@ static void relocate_syms(TCCState *s1, int do_resolve) } } -/* relocate a given section (CPU dependant) */ +/* relocate a given section (CPU dependent) */ static void relocate_section(TCCState *s1, Section *s) { Section *sr; @@ -581,7 +581,7 @@ static void put_got_offset(TCCState *s1, int index, unsigned long val) } /* XXX: suppress that */ -static void put32(unsigned char *p, unsigned int val) +static void put32(unsigned char *p, uint32_t val) { p[0] = val; p[1] = val >> 8; @@ -589,6 +589,11 @@ static void put32(unsigned char *p, unsigned int val) p[3] = val >> 24; } +static uint32_t get32(unsigned char *p) +{ + return p[0] | (p[1] << 8) | (p[2] << 16) | (p[3] << 24); +} + static void build_got(TCCState *s1) { unsigned char *ptr; @@ -632,10 +637,43 @@ static void put_got_entry(TCCState *s1, sym = &((Elf32_Sym *)symtab_section->data)[sym_index]; name = symtab_section->link->data + sym->st_name; offset = sym->st_value; - /* NOTE: we put temporarily the got offset */ if (reloc_type == R_386_JMP_SLOT) { - s1->nb_plt_entries++; - offset = s1->got->data_offset; + Section *plt; + uint8_t *p; + int modrm; + + /* if we build a DLL, we add a %ebx offset */ + if (s1->output_type == TCC_OUTPUT_DLL) + modrm = 0xa3; + else + modrm = 0x25; + + /* add a PLT entry */ + plt = s1->plt; + if (plt->data_offset == 0) { + /* first plt entry */ + p = section_ptr_add(plt, 16); + p[0] = 0xff; /* pushl got + 4 */ + p[1] = modrm + 0x10; + put32(p + 2, 4); + p[6] = 0xff; /* jmp *(got + 8) */ + p[7] = modrm; + put32(p + 8, 8); + } + + p = section_ptr_add(plt, 16); + p[0] = 0xff; /* jmp *(got + x) */ + p[1] = modrm; + put32(p + 2, s1->got->data_offset); + p[6] = 0x68; /* push $xxx */ + put32(p + 7, (plt->data_offset - 32) >> 1); + p[11] = 0xe9; /* jmp plt_start */ + put32(p + 12, -(plt->data_offset)); + + /* the symbol is modified so that it will be relocated to + the PLT */ + if (s1->output_type == TCC_OUTPUT_EXE) + offset = plt->data_offset - 16; } index = put_elf_sym(s1->dynsym, offset, size, info, 0, sym->st_shndx, name); @@ -847,7 +885,7 @@ int tcc_output_file(TCCState *s1, const char *filename) Section *strsec, *s; Elf32_Shdr shdr, *sh; Elf32_Phdr *phdr, *ph; - Section *interp, *plt, *dynamic, *dynstr; + Section *interp, *dynamic, *dynstr; unsigned long saved_dynamic_data_offset; Elf32_Sym *sym; int type, file_type; @@ -863,7 +901,6 @@ int tcc_output_file(TCCState *s1, const char *filename) section_order = NULL; interp = NULL; dynamic = NULL; - plt = NULL; /* avoid warning */ dynstr = NULL; /* avoid warning */ saved_dynamic_data_offset = 0; /* avoid warning */ @@ -898,8 +935,9 @@ int tcc_output_file(TCCState *s1, const char *filename) dynamic->sh_entsize = sizeof(Elf32_Dyn); /* add PLT */ - plt = new_section(s1, ".plt", SHT_PROGBITS, SHF_ALLOC | SHF_EXECINSTR); - plt->sh_entsize = 4; + s1->plt = new_section(s1, ".plt", SHT_PROGBITS, + SHF_ALLOC | SHF_EXECINSTR); + s1->plt->sh_entsize = 4; build_got(s1); @@ -998,9 +1036,6 @@ int tcc_output_file(TCCState *s1, const char *filename) build_got_entries(s1); - /* update PLT/GOT sizes so that we can allocate their space */ - plt->data_offset += 16 * (s1->nb_plt_entries + 1); - /* add a list of needed dlls */ for(i = 0; i < s1->nb_loaded_dlls; i++) { DLLReference *dllref = s1->loaded_dlls[i]; @@ -1191,8 +1226,6 @@ int tcc_output_file(TCCState *s1, const char *filename) /* if dynamic section, then add corresponing program header */ if (dynamic) { - int plt_offset; - unsigned char *p; Elf32_Sym *sym_end; ph = &phdr[phnum - 1]; @@ -1209,49 +1242,38 @@ int tcc_output_file(TCCState *s1, const char *filename) /* put GOT dynamic section address */ put32(s1->got->data, dynamic->sh_addr); - /* compute the PLT */ - plt->data_offset = 0; - - /* first plt entry */ - p = section_ptr_add(plt, 16); - p[0] = 0xff; /* pushl got + 4 */ - p[1] = 0x35; - put32(p + 2, s1->got->sh_addr + 4); - p[6] = 0xff; /* jmp *(got + 8) */ - p[7] = 0x25; - put32(p + 8, s1->got->sh_addr + 8); - - /* relocation symbols in .dynsym and build PLT. */ - plt_offset = 0; + /* relocate the PLT */ + if (file_type == TCC_OUTPUT_EXE) { + uint8_t *p, *p_end; + + p = s1->plt->data; + p_end = p + s1->plt->data_offset; + put32(p + 2, get32(p + 2) + s1->got->sh_addr); + put32(p + 8, get32(p + 8) + s1->got->sh_addr); + p += 16; + while (p < p_end) { + put32(p + 2, get32(p + 2) + s1->got->sh_addr); + p += 16; + } + } + + /* relocate symbols in .dynsym */ sym_end = (Elf32_Sym *)(s1->dynsym->data + s1->dynsym->data_offset); for(sym = (Elf32_Sym *)s1->dynsym->data + 1; sym < sym_end; sym++) { - type = ELF32_ST_TYPE(sym->st_info); if (sym->st_shndx == SHN_UNDEF) { - if (type == STT_FUNC) { - /* one more entry in PLT */ - p = section_ptr_add(plt, 16); - p[0] = 0xff; /* jmp *(got + x) */ - p[1] = 0x25; - put32(p + 2, s1->got->sh_addr + sym->st_value); - p[6] = 0x68; /* push $xxx */ - put32(p + 7, plt_offset); - p[11] = 0xe9; /* jmp plt_start */ - put32(p + 12, -(plt->data_offset)); - - /* patch symbol value to point to plt */ - sym->st_value = plt->sh_addr + p - plt->data; - - plt_offset += 8; - } + /* relocate to the PLT if the symbol corresponds + to a PLT entry */ + if (sym->st_value) + sym->st_value += s1->plt->sh_addr; } else if (sym->st_shndx < SHN_LORESERVE) { /* do symbol relocation */ sym->st_value += s1->sections[sym->st_shndx]->sh_addr; } } - /* put dynamic section entries */ + /* put dynamic section entries */ dynamic->data_offset = saved_dynamic_data_offset; put_dt(dynamic, DT_HASH, s1->dynsym->hash->sh_addr); put_dt(dynamic, DT_STRTAB, dynstr->sh_addr); |