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2 * Generic Dynamic compiler generator
4 * Copyright (c) 2003 Fabrice Bellard
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
30 /* all dynamically generated functions begin with this code */
31 #define OP_PREFIX "op_"
33 int elf_must_swap(Elf32_Ehdr
*h
)
41 return (h
->e_ident
[EI_DATA
] == ELFDATA2MSB
) !=
45 void swab16s(uint16_t *p
)
50 void swab32s(uint32_t *p
)
55 void swab64s(uint32_t *p
)
60 void elf_swap_ehdr(Elf32_Ehdr
*h
)
62 swab16s(&h
->e_type
); /* Object file type */
63 swab16s(&h
-> e_machine
); /* Architecture */
64 swab32s(&h
-> e_version
); /* Object file version */
65 swab32s(&h
-> e_entry
); /* Entry point virtual address */
66 swab32s(&h
-> e_phoff
); /* Program header table file offset */
67 swab32s(&h
-> e_shoff
); /* Section header table file offset */
68 swab32s(&h
-> e_flags
); /* Processor-specific flags */
69 swab16s(&h
-> e_ehsize
); /* ELF header size in bytes */
70 swab16s(&h
-> e_phentsize
); /* Program header table entry size */
71 swab16s(&h
-> e_phnum
); /* Program header table entry count */
72 swab16s(&h
-> e_shentsize
); /* Section header table entry size */
73 swab16s(&h
-> e_shnum
); /* Section header table entry count */
74 swab16s(&h
-> e_shstrndx
); /* Section header string table index */
77 void elf_swap_shdr(Elf32_Shdr
*h
)
79 swab32s(&h
-> sh_name
); /* Section name (string tbl index) */
80 swab32s(&h
-> sh_type
); /* Section type */
81 swab32s(&h
-> sh_flags
); /* Section flags */
82 swab32s(&h
-> sh_addr
); /* Section virtual addr at execution */
83 swab32s(&h
-> sh_offset
); /* Section file offset */
84 swab32s(&h
-> sh_size
); /* Section size in bytes */
85 swab32s(&h
-> sh_link
); /* Link to another section */
86 swab32s(&h
-> sh_info
); /* Additional section information */
87 swab32s(&h
-> sh_addralign
); /* Section alignment */
88 swab32s(&h
-> sh_entsize
); /* Entry size if section holds table */
91 void elf_swap_phdr(Elf32_Phdr
*h
)
93 swab32s(&h
->p_type
); /* Segment type */
94 swab32s(&h
->p_offset
); /* Segment file offset */
95 swab32s(&h
->p_vaddr
); /* Segment virtual address */
96 swab32s(&h
->p_paddr
); /* Segment physical address */
97 swab32s(&h
->p_filesz
); /* Segment size in file */
98 swab32s(&h
->p_memsz
); /* Segment size in memory */
99 swab32s(&h
->p_flags
); /* Segment flags */
100 swab32s(&h
->p_align
); /* Segment alignment */
106 uint16_t get16(uint16_t *p
)
115 uint32_t get32(uint32_t *p
)
124 void put16(uint16_t *p
, uint16_t val
)
131 void put32(uint32_t *p
, uint32_t val
)
138 void __attribute__((noreturn
)) error(const char *fmt
, ...)
142 fprintf(stderr
, "dyngen: ");
143 vfprintf(stderr
, fmt
, ap
);
144 fprintf(stderr
, "\n");
150 Elf32_Shdr
*find_elf_section(Elf32_Shdr
*shdr
, int shnum
, const char *shstr
,
157 for(i
= 0; i
< shnum
; i
++) {
161 shname
= shstr
+ sec
->sh_name
;
162 if (!strcmp(shname
, name
))
168 void *load_data(int fd
, long offset
, unsigned int size
)
175 lseek(fd
, offset
, SEEK_SET
);
176 if (read(fd
, data
, size
) != size
) {
183 int strstart(const char *str
, const char *val
, const char **ptr
)
201 /* generate op code */
202 void gen_code(const char *name
, unsigned long offset
, unsigned long size
,
203 FILE *outfile
, uint8_t *text
, void *relocs
, int nb_relocs
, int reloc_sh_type
,
204 Elf32_Sym
*symtab
, char *strtab
, int gen_switch
)
207 uint8_t *p_start
, *p_end
;
209 uint8_t args_present
[MAX_ARGS
];
210 const char *sym_name
, *p
;
212 /* compute exact size excluding return instruction */
213 p_start
= text
+ offset
;
214 p_end
= p_start
+ size
;
221 error("empty code for %s", name
);
223 error("ret expected at the end of %s", name
);
224 copy_size
= p
- p_start
;
230 p
= (void *)(p_end
- 4);
232 while (p
> p_start
&& get32((uint32_t *)p
) != 0x4e800020)
234 /* skip double ret */
235 if (p
> p_start
&& get32((uint32_t *)(p
- 4)) == 0x4e800020)
238 error("empty code for %s", name
);
239 copy_size
= p
- p_start
;
243 error("unsupported CPU (%d)", e_machine
);
246 /* compute the number of arguments by looking at the relocations */
247 for(i
= 0;i
< MAX_ARGS
; i
++)
250 if (reloc_sh_type
== SHT_REL
) {
253 for(i
= 0, rel
= relocs
;i
< nb_relocs
; i
++, rel
++) {
254 if (rel
->r_offset
>= offset
&& rel
->r_offset
< offset
+ copy_size
) {
255 sym_name
= strtab
+ symtab
[ELF32_R_SYM(rel
->r_info
)].st_name
;
256 if (strstart(sym_name
, "__op_param", &p
)) {
257 n
= strtoul(p
, NULL
, 10);
259 error("too many arguments in %s", name
);
260 args_present
[n
- 1] = 1;
267 for(i
= 0, rel
= relocs
;i
< nb_relocs
; i
++, rel
++) {
268 if (rel
->r_offset
>= offset
&& rel
->r_offset
< offset
+ copy_size
) {
269 sym_name
= strtab
+ symtab
[ELF32_R_SYM(rel
->r_info
)].st_name
;
270 if (strstart(sym_name
, "__op_param", &p
)) {
271 n
= strtoul(p
, NULL
, 10);
273 error("too many arguments in %s", name
);
274 args_present
[n
- 1] = 1;
281 while (nb_args
< MAX_ARGS
&& args_present
[nb_args
])
283 for(i
= nb_args
; i
< MAX_ARGS
; i
++) {
285 error("inconsistent argument numbering in %s", name
);
291 fprintf(outfile
, "case INDEX_%s: {\n", name
);
293 fprintf(outfile
, " long ");
294 for(i
= 0; i
< nb_args
; i
++) {
296 fprintf(outfile
, ", ");
297 fprintf(outfile
, "param%d", i
+ 1);
299 fprintf(outfile
, ";\n");
301 fprintf(outfile
, " extern void %s();\n", name
);
303 if (reloc_sh_type
== SHT_REL
) {
305 for(i
= 0, rel
= relocs
;i
< nb_relocs
; i
++, rel
++) {
306 if (rel
->r_offset
>= offset
&& rel
->r_offset
< offset
+ copy_size
) {
307 sym_name
= strtab
+ symtab
[ELF32_R_SYM(rel
->r_info
)].st_name
;
308 if (!strstart(sym_name
, "__op_param", &p
)) {
309 fprintf(outfile
, "extern char %s;\n", sym_name
);
315 for(i
= 0, rel
= relocs
;i
< nb_relocs
; i
++, rel
++) {
316 if (rel
->r_offset
>= offset
&& rel
->r_offset
< offset
+ copy_size
) {
317 sym_name
= strtab
+ symtab
[ELF32_R_SYM(rel
->r_info
)].st_name
;
318 if (!strstart(sym_name
, "__op_param", &p
)) {
319 fprintf(outfile
, "extern char %s;\n", sym_name
);
325 fprintf(outfile
, " memcpy(gen_code_ptr, &%s, %d);\n", name
, copy_size
);
326 for(i
= 0; i
< nb_args
; i
++) {
327 fprintf(outfile
, " param%d = *opparam_ptr++;\n", i
+ 1);
330 /* patch relocations */
338 for(i
= 0, rel
= relocs
;i
< nb_relocs
; i
++, rel
++) {
339 if (rel
->r_offset
>= offset
&& rel
->r_offset
< offset
+ copy_size
) {
340 sym_name
= strtab
+ symtab
[ELF32_R_SYM(rel
->r_info
)].st_name
;
341 if (strstart(sym_name
, "__op_param", &p
)) {
342 snprintf(name
, sizeof(name
), "param%s", p
);
344 snprintf(name
, sizeof(name
), "(long)(&%s)", sym_name
);
346 type
= ELF32_R_TYPE(rel
->r_info
);
347 addend
= get32((uint32_t *)(text
+ rel
->r_offset
));
350 fprintf(outfile
, " *(uint32_t *)(gen_code_ptr + %ld) = %s + %ld;\n",
351 rel
->r_offset
- offset
, name
, addend
);
354 fprintf(outfile
, " *(uint32_t *)(gen_code_ptr + %ld) = %s - (long)(gen_code_ptr + %ld) + %ld;\n",
355 rel
->r_offset
- offset
, name
, rel
->r_offset
- offset
, addend
);
358 error("unsupported i386 relocation (%d)", type
);
365 error("unsupported CPU for relocations (%d)", e_machine
);
367 fprintf(outfile
, " gen_code_ptr += %d;\n", copy_size
);
368 fprintf(outfile
, "}\n");
369 fprintf(outfile
, "break;\n\n");
371 fprintf(outfile
, "static inline void gen_%s(", name
);
373 fprintf(outfile
, "void");
375 for(i
= 0; i
< nb_args
; i
++) {
377 fprintf(outfile
, ", ");
378 fprintf(outfile
, "long param%d", i
+ 1);
381 fprintf(outfile
, ")\n");
382 fprintf(outfile
, "{\n");
383 for(i
= 0; i
< nb_args
; i
++) {
384 fprintf(outfile
, " *gen_opparam_ptr++ = param%d;\n", i
+ 1);
386 fprintf(outfile
, " *gen_opc_ptr++ = INDEX_%s;\n", name
);
387 fprintf(outfile
, "}\n\n");
391 /* load an elf object file */
392 int load_elf(const char *filename
, FILE *outfile
, int do_print_enum
)
396 Elf32_Shdr
*sec
, *shdr
, *symtab_sec
, *strtab_sec
, *text_sec
;
398 Elf32_Sym
*symtab
, *sym
;
399 const char *cpu_name
;
400 char *shstr
, *strtab
;
403 int nb_relocs
, reloc_sh_type
;
405 fd
= open(filename
, O_RDONLY
);
407 error("can't open file '%s'", filename
);
409 /* Read ELF header. */
410 if (read(fd
, &ehdr
, sizeof (ehdr
)) != sizeof (ehdr
))
411 error("unable to read file header");
413 /* Check ELF identification. */
414 if (ehdr
.e_ident
[EI_MAG0
] != ELFMAG0
415 || ehdr
.e_ident
[EI_MAG1
] != ELFMAG1
416 || ehdr
.e_ident
[EI_MAG2
] != ELFMAG2
417 || ehdr
.e_ident
[EI_MAG3
] != ELFMAG3
418 || ehdr
.e_ident
[EI_CLASS
] != ELFCLASS32
419 || ehdr
.e_ident
[EI_VERSION
] != EV_CURRENT
) {
420 error("bad ELF header");
423 do_swap
= elf_must_swap(&ehdr
);
425 elf_swap_ehdr(&ehdr
);
426 if (ehdr
.e_type
!= ET_REL
)
427 error("ELF object file expected");
428 if (ehdr
.e_version
!= EV_CURRENT
)
429 error("Invalid ELF version");
430 e_machine
= ehdr
.e_machine
;
432 /* read section headers */
433 shdr
= load_data(fd
, ehdr
.e_shoff
, ehdr
.e_shnum
* sizeof(Elf32_Shdr
));
435 for(i
= 0; i
< ehdr
.e_shnum
; i
++) {
436 elf_swap_shdr(&shdr
[i
]);
440 sec
= &shdr
[ehdr
.e_shstrndx
];
441 shstr
= load_data(fd
, sec
->sh_offset
, sec
->sh_size
);
445 text_sec
= find_elf_section(shdr
, ehdr
.e_shnum
, shstr
, ".text");
447 error("could not find .text section");
448 text
= load_data(fd
, text_sec
->sh_offset
, text_sec
->sh_size
);
450 /* find text relocations, if any */
454 for(i
= 0; i
< ehdr
.e_shnum
; i
++) {
456 if ((sec
->sh_type
== SHT_REL
|| sec
->sh_type
== SHT_RELA
) &&
457 sec
->sh_info
== (text_sec
- shdr
)) {
458 reloc_sh_type
= sec
->sh_type
;
459 relocs
= load_data(fd
, sec
->sh_offset
, sec
->sh_size
);
460 nb_relocs
= sec
->sh_size
/ sec
->sh_entsize
;
462 if (sec
->sh_type
== SHT_REL
) {
463 Elf32_Rel
*rel
= relocs
;
464 for(j
= 0, rel
= relocs
; j
< nb_relocs
; j
++, rel
++) {
465 swab32s(&rel
->r_offset
);
466 swab32s(&rel
->r_info
);
469 Elf32_Rela
*rel
= relocs
;
470 for(j
= 0, rel
= relocs
; j
< nb_relocs
; j
++, rel
++) {
471 swab32s(&rel
->r_offset
);
472 swab32s(&rel
->r_info
);
473 swab32s(&rel
->r_addend
);
481 symtab_sec
= find_elf_section(shdr
, ehdr
.e_shnum
, shstr
, ".symtab");
483 error("could not find .symtab section");
484 strtab_sec
= &shdr
[symtab_sec
->sh_link
];
486 symtab
= load_data(fd
, symtab_sec
->sh_offset
, symtab_sec
->sh_size
);
487 strtab
= load_data(fd
, strtab_sec
->sh_offset
, strtab_sec
->sh_size
);
489 nb_syms
= symtab_sec
->sh_size
/ sizeof(Elf32_Sym
);
491 for(i
= 0, sym
= symtab
; i
< nb_syms
; i
++, sym
++) {
492 swab32s(&sym
->st_name
);
493 swab32s(&sym
->st_value
);
494 swab32s(&sym
->st_size
);
495 swab16s(&sym
->st_shndx
);
516 error("unsupported CPU (e_machine=%d)", e_machine
);
520 fprintf(outfile
, "DEF(end)\n");
521 for(i
= 0, sym
= symtab
; i
< nb_syms
; i
++, sym
++) {
522 const char *name
, *p
;
523 name
= strtab
+ sym
->st_name
;
524 if (strstart(name
, OP_PREFIX
, &p
)) {
525 fprintf(outfile
, "DEF(%s)\n", p
);
529 /* generate big code generation switch */
531 "int dyngen_code(uint8_t *gen_code_buf,\n"
532 " const uint16_t *opc_buf, const uint32_t *opparam_buf)\n"
534 " uint8_t *gen_code_ptr;\n"
535 " const uint16_t *opc_ptr;\n"
536 " const uint32_t *opparam_ptr;\n"
537 " gen_code_ptr = gen_code_buf;\n"
538 " opc_ptr = opc_buf;\n"
539 " opparam_ptr = opparam_buf;\n"
541 " switch(*opc_ptr++) {\n"
544 for(i
= 0, sym
= symtab
; i
< nb_syms
; i
++, sym
++) {
546 name
= strtab
+ sym
->st_name
;
547 if (strstart(name
, OP_PREFIX
, NULL
)) {
549 printf("%4d: %s pos=0x%08x len=%d\n",
550 i
, name
, sym
->st_value
, sym
->st_size
);
552 if (sym
->st_shndx
!= (text_sec
- shdr
))
553 error("invalid section for opcode (0x%x)", sym
->st_shndx
);
554 gen_code(name
, sym
->st_value
, sym
->st_size
, outfile
,
555 text
, relocs
, nb_relocs
, reloc_sh_type
, symtab
, strtab
, 1);
567 /* generate a return */
570 fprintf(outfile
, "*gen_code_ptr++ = 0xc3; /* ret */\n");
573 error("no return generation for cpu '%s'", cpu_name
);
576 fprintf(outfile
, "return gen_code_ptr - gen_code_buf;\n");
577 fprintf(outfile
, "}\n\n");
579 /* generate gen_xxx functions */
580 /* XXX: suppress the use of these functions to simplify code */
581 for(i
= 0, sym
= symtab
; i
< nb_syms
; i
++, sym
++) {
583 name
= strtab
+ sym
->st_name
;
584 if (strstart(name
, OP_PREFIX
, NULL
)) {
585 if (sym
->st_shndx
!= (text_sec
- shdr
))
586 error("invalid section for opcode (0x%x)", sym
->st_shndx
);
587 gen_code(name
, sym
->st_value
, sym
->st_size
, outfile
,
588 text
, relocs
, nb_relocs
, reloc_sh_type
, symtab
, strtab
, 0);
599 printf("dyngen (c) 2003 Fabrice Bellard\n"
600 "usage: dyngen [-o outfile] [-c] objfile\n"
601 "Generate a dynamic code generator from an object file\n"
602 "-c output enum of operations\n"
607 int main(int argc
, char **argv
)
609 int c
, do_print_enum
;
610 const char *filename
, *outfilename
;
613 outfilename
= "out.c";
616 c
= getopt(argc
, argv
, "ho:c");
624 outfilename
= optarg
;
633 filename
= argv
[optind
];
634 outfile
= fopen(outfilename
, "w");
636 error("could not open '%s'", outfilename
);
637 load_elf(filename
, outfile
, do_print_enum
);