#ifdef TARGET_DEFS_ONLY #define EM_TCC_TARGET EM_386 /* relocation type for 32 bit data relocation */ #define R_DATA_32 R_386_32 #define R_DATA_PTR R_386_32 #define R_JMP_SLOT R_386_JMP_SLOT #define R_GLOB_DAT R_386_GLOB_DAT #define R_COPY R_386_COPY #define R_RELATIVE R_386_RELATIVE #define R_NUM R_386_NUM #define ELF_START_ADDR 0x08048000 #define ELF_PAGE_SIZE 0x1000 #define PCRELATIVE_DLLPLT 0 #define RELOCATE_DLLPLT 0 #else /* !TARGET_DEFS_ONLY */ #include "tcc.h" /* Returns 1 for a code relocation, 0 for a data relocation. For unknown relocations, returns -1. */ int code_reloc (int reloc_type) { switch (reloc_type) { case R_386_RELATIVE: case R_386_16: case R_386_32: case R_386_GOTPC: case R_386_GOTOFF: case R_386_GOT32: case R_386_GOT32X: case R_386_GLOB_DAT: case R_386_COPY: return 0; case R_386_PC16: case R_386_PC32: case R_386_PLT32: case R_386_JMP_SLOT: return 1; } tcc_error ("Unknown relocation type: %d", reloc_type); return -1; } /* Returns an enumerator to describe whether and when the relocation needs a GOT and/or PLT entry to be created. See tcc.h for a description of the different values. */ int gotplt_entry_type (int reloc_type) { switch (reloc_type) { case R_386_RELATIVE: case R_386_16: case R_386_GLOB_DAT: case R_386_JMP_SLOT: case R_386_COPY: return NO_GOTPLT_ENTRY; case R_386_32: /* This relocations shouldn't normally need GOT or PLT slots if it weren't for simplicity in the code generator. See our caller for comments. */ return AUTO_GOTPLT_ENTRY; case R_386_PC16: case R_386_PC32: return AUTO_GOTPLT_ENTRY; case R_386_GOTPC: case R_386_GOTOFF: return BUILD_GOT_ONLY; case R_386_GOT32: case R_386_GOT32X: case R_386_PLT32: return ALWAYS_GOTPLT_ENTRY; } tcc_error ("Unknown relocation type: %d", reloc_type); return -1; } ST_FUNC unsigned create_plt_entry(TCCState *s1, unsigned got_offset, struct sym_attr *attr) { Section *plt = s1->plt; uint8_t *p; int modrm; unsigned plt_offset, relofs; /* on i386 if we build a DLL, we add a %ebx offset */ if (s1->output_type == TCC_OUTPUT_DLL) modrm = 0xa3; else modrm = 0x25; /* empty PLT: create PLT0 entry that pushes the library identifier (GOT + PTR_SIZE) and jumps to ld.so resolution routine (GOT + 2 * PTR_SIZE) */ if (plt->data_offset == 0) { p = section_ptr_add(plt, 16); p[0] = 0xff; /* pushl got + PTR_SIZE */ p[1] = modrm + 0x10; write32le(p + 2, PTR_SIZE); p[6] = 0xff; /* jmp *(got + PTR_SIZE * 2) */ p[7] = modrm; write32le(p + 8, PTR_SIZE * 2); } plt_offset = plt->data_offset; /* The PLT slot refers to the relocation entry it needs via offset. The reloc entry is created below, so its offset is the current data_offset */ relofs = s1->got->reloc ? s1->got->reloc->data_offset : 0; /* Jump to GOT entry where ld.so initially put the address of ip + 4 */ p = section_ptr_add(plt, 16); p[0] = 0xff; /* jmp *(got + x) */ p[1] = modrm; write32le(p + 2, got_offset); p[6] = 0x68; /* push $xxx */ write32le(p + 7, relofs); p[11] = 0xe9; /* jmp plt_start */ write32le(p + 12, -(plt->data_offset)); return plt_offset; } /* relocate the PLT: compute addresses and offsets in the PLT now that final address for PLT and GOT are known (see fill_program_header) */ ST_FUNC void relocate_plt(TCCState *s1) { uint8_t *p, *p_end; if (!s1->plt) return; p = s1->plt->data; p_end = p + s1->plt->data_offset; if (p < p_end) { add32le(p + 2, s1->got->sh_addr); add32le(p + 8, s1->got->sh_addr); p += 16; while (p < p_end) { add32le(p + 2, s1->got->sh_addr); p += 16; } } } static ElfW_Rel *qrel; /* ptr to next reloc entry reused */ void relocate_init(Section *sr) { qrel = (ElfW_Rel *) sr->data; } void relocate(TCCState *s1, ElfW_Rel *rel, int type, unsigned char *ptr, addr_t addr, addr_t val) { int sym_index, esym_index; sym_index = ELFW(R_SYM)(rel->r_info); switch (type) { case R_386_32: if (s1->output_type == TCC_OUTPUT_DLL) { esym_index = s1->sym_attrs[sym_index].dyn_index; qrel->r_offset = rel->r_offset; if (esym_index) { qrel->r_info = ELFW(R_INFO)(esym_index, R_386_32); qrel++; return; } else { qrel->r_info = ELFW(R_INFO)(0, R_386_RELATIVE); qrel++; } } add32le(ptr, val); return; case R_386_PC32: if (s1->output_type == TCC_OUTPUT_DLL) { /* DLL relocation */ esym_index = s1->sym_attrs[sym_index].dyn_index; if (esym_index) { qrel->r_offset = rel->r_offset; qrel->r_info = ELFW(R_INFO)(esym_index, R_386_PC32); qrel++; return; } } add32le(ptr, val - addr); return; case R_386_PLT32: add32le(ptr, val - addr); return; case R_386_GLOB_DAT: case R_386_JMP_SLOT: write32le(ptr, val); return; case R_386_GOTPC: add32le(ptr, s1->got->sh_addr - addr); return; case R_386_GOTOFF: add32le(ptr, val - s1->got->sh_addr); return; case R_386_GOT32: case R_386_GOT32X: /* we load the got offset */ add32le(ptr, s1->sym_attrs[sym_index].got_offset); return; case R_386_16: if (s1->output_format != TCC_OUTPUT_FORMAT_BINARY) { output_file: tcc_error("can only produce 16-bit binary files"); } write16le(ptr, read16le(ptr) + val); return; case R_386_PC16: if (s1->output_format != TCC_OUTPUT_FORMAT_BINARY) goto output_file; write16le(ptr, read16le(ptr) + val - addr); return; case R_386_RELATIVE: #ifdef TCC_TARGET_PE add32le(ptr, val - s1->pe_imagebase); #endif /* do nothing */ return; case R_386_COPY: /* This relocation must copy initialized data from the library to the program .bss segment. Currently made like for ARM (to remove noise of default case). Is this true? */ return; default: fprintf(stderr,"FIXME: handle reloc type %d at %x [%p] to %x\n", type, (unsigned)addr, ptr, (unsigned)val); return; } } #endif /* !TARGET_DEFS_ONLY */