]> git.proxmox.com Git - mirror_qemu.git/blob - dyngen.c
added float support
[mirror_qemu.git] / dyngen.c
1 #include <stdlib.h>
2 #include <stdio.h>
3 #include <stdarg.h>
4 #include <inttypes.h>
5 #include <elf.h>
6 #include <unistd.h>
7 #include <fcntl.h>
8
9 #include "thunk.h"
10
11 /* all dynamically generated functions begin with this code */
12 #define OP_PREFIX "op"
13
14 int elf_must_swap(Elf32_Ehdr *h)
15 {
16 union {
17 uint32_t i;
18 uint8_t b[4];
19 } swaptest;
20
21 swaptest.i = 1;
22 return (h->e_ident[EI_DATA] == ELFDATA2MSB) !=
23 (swaptest.b[0] == 0);
24 }
25
26 void swab16s(uint16_t *p)
27 {
28 *p = bswap16(*p);
29 }
30
31 void swab32s(uint32_t *p)
32 {
33 *p = bswap32(*p);
34 }
35
36 void swab64s(uint32_t *p)
37 {
38 *p = bswap64(*p);
39 }
40
41 void elf_swap_ehdr(Elf32_Ehdr *h)
42 {
43 swab16s(&h->e_type); /* Object file type */
44 swab16s(&h-> e_machine); /* Architecture */
45 swab32s(&h-> e_version); /* Object file version */
46 swab32s(&h-> e_entry); /* Entry point virtual address */
47 swab32s(&h-> e_phoff); /* Program header table file offset */
48 swab32s(&h-> e_shoff); /* Section header table file offset */
49 swab32s(&h-> e_flags); /* Processor-specific flags */
50 swab16s(&h-> e_ehsize); /* ELF header size in bytes */
51 swab16s(&h-> e_phentsize); /* Program header table entry size */
52 swab16s(&h-> e_phnum); /* Program header table entry count */
53 swab16s(&h-> e_shentsize); /* Section header table entry size */
54 swab16s(&h-> e_shnum); /* Section header table entry count */
55 swab16s(&h-> e_shstrndx); /* Section header string table index */
56 }
57
58 void elf_swap_shdr(Elf32_Shdr *h)
59 {
60 swab32s(&h-> sh_name); /* Section name (string tbl index) */
61 swab32s(&h-> sh_type); /* Section type */
62 swab32s(&h-> sh_flags); /* Section flags */
63 swab32s(&h-> sh_addr); /* Section virtual addr at execution */
64 swab32s(&h-> sh_offset); /* Section file offset */
65 swab32s(&h-> sh_size); /* Section size in bytes */
66 swab32s(&h-> sh_link); /* Link to another section */
67 swab32s(&h-> sh_info); /* Additional section information */
68 swab32s(&h-> sh_addralign); /* Section alignment */
69 swab32s(&h-> sh_entsize); /* Entry size if section holds table */
70 }
71
72 void elf_swap_phdr(Elf32_Phdr *h)
73 {
74 swab32s(&h->p_type); /* Segment type */
75 swab32s(&h->p_offset); /* Segment file offset */
76 swab32s(&h->p_vaddr); /* Segment virtual address */
77 swab32s(&h->p_paddr); /* Segment physical address */
78 swab32s(&h->p_filesz); /* Segment size in file */
79 swab32s(&h->p_memsz); /* Segment size in memory */
80 swab32s(&h->p_flags); /* Segment flags */
81 swab32s(&h->p_align); /* Segment alignment */
82 }
83
84 int do_swap;
85 int e_machine;
86
87 uint16_t get16(uint16_t *p)
88 {
89 uint16_t val;
90 val = *p;
91 if (do_swap)
92 val = bswap16(val);
93 return val;
94 }
95
96 uint32_t get32(uint32_t *p)
97 {
98 uint32_t val;
99 val = *p;
100 if (do_swap)
101 val = bswap32(val);
102 return val;
103 }
104
105 void put16(uint16_t *p, uint16_t val)
106 {
107 if (do_swap)
108 val = bswap16(val);
109 *p = val;
110 }
111
112 void put32(uint32_t *p, uint32_t val)
113 {
114 if (do_swap)
115 val = bswap32(val);
116 *p = val;
117 }
118
119 void __attribute__((noreturn)) error(const char *fmt, ...)
120 {
121 va_list ap;
122 va_start(ap, fmt);
123 fprintf(stderr, "dyngen: ");
124 vfprintf(stderr, fmt, ap);
125 fprintf(stderr, "\n");
126 va_end(ap);
127 exit(1);
128 }
129
130
131 Elf32_Shdr *find_elf_section(Elf32_Shdr *shdr, int shnum, const char *shstr,
132 const char *name)
133 {
134 int i;
135 const char *shname;
136 Elf32_Shdr *sec;
137
138 for(i = 0; i < shnum; i++) {
139 sec = &shdr[i];
140 if (!sec->sh_name)
141 continue;
142 shname = shstr + sec->sh_name;
143 if (!strcmp(shname, name))
144 return sec;
145 }
146 return NULL;
147 }
148
149 void *load_data(int fd, long offset, unsigned int size)
150 {
151 char *data;
152
153 data = malloc(size);
154 if (!data)
155 return NULL;
156 lseek(fd, offset, SEEK_SET);
157 if (read(fd, data, size) != size) {
158 free(data);
159 return NULL;
160 }
161 return data;
162 }
163
164 int strstart(const char *str, const char *val, const char **ptr)
165 {
166 const char *p, *q;
167 p = str;
168 q = val;
169 while (*q != '\0') {
170 if (*p != *q)
171 return 0;
172 p++;
173 q++;
174 }
175 if (ptr)
176 *ptr = p;
177 return 1;
178 }
179
180 #define MAX_ARGS 3
181
182 /* generate op code */
183 void gen_code(const char *name, unsigned long offset, unsigned long size,
184 FILE *outfile, uint8_t *text, void *relocs, int nb_relocs, int reloc_sh_type,
185 Elf32_Sym *symtab, char *strtab)
186 {
187 int copy_size = 0;
188 uint8_t *p_start, *p_end;
189 int nb_args, i;
190 uint8_t args_present[MAX_ARGS];
191 const char *sym_name, *p;
192
193 /* compute exact size excluding return instruction */
194 p_start = text + offset;
195 p_end = p_start + size;
196 switch(e_machine) {
197 case EM_386:
198 {
199 uint8_t *p;
200 p = p_end - 1;
201 /* find ret */
202 while (p > p_start && *p != 0xc3)
203 p--;
204 /* skip double ret */
205 if (p > p_start && p[-1] == 0xc3)
206 p--;
207 if (p == p_start)
208 error("empty code for %s", name);
209 copy_size = p - p_start;
210 }
211 break;
212 case EM_PPC:
213 {
214 uint8_t *p;
215 p = (void *)(p_end - 4);
216 /* find ret */
217 while (p > p_start && get32((uint32_t *)p) != 0x4e800020)
218 p -= 4;
219 /* skip double ret */
220 if (p > p_start && get32((uint32_t *)(p - 4)) == 0x4e800020)
221 p -= 4;
222 if (p == p_start)
223 error("empty code for %s", name);
224 copy_size = p - p_start;
225 }
226 break;
227 default:
228 error("unsupported CPU (%d)", e_machine);
229 }
230
231 /* compute the number of arguments by looking at the relocations */
232 for(i = 0;i < MAX_ARGS; i++)
233 args_present[i] = 0;
234
235 if (reloc_sh_type == SHT_REL) {
236 Elf32_Rel *rel;
237 int n;
238 for(i = 0, rel = relocs;i < nb_relocs; i++, rel++) {
239 if (rel->r_offset >= offset && rel->r_offset < offset + copy_size) {
240 sym_name = strtab + symtab[ELF32_R_SYM(rel->r_info)].st_name;
241 if (strstart(sym_name, "__op_param", &p)) {
242 n = strtoul(p, NULL, 10);
243 if (n >= MAX_ARGS)
244 error("too many arguments in %s", name);
245 args_present[n - 1] = 1;
246 } else {
247 fprintf(outfile, "extern char %s;\n", sym_name);
248 }
249 }
250 }
251 } else {
252 Elf32_Rela *rel;
253 int n;
254 for(i = 0, rel = relocs;i < nb_relocs; i++, rel++) {
255 if (rel->r_offset >= offset && rel->r_offset < offset + copy_size) {
256 sym_name = strtab + symtab[ELF32_R_SYM(rel->r_info)].st_name;
257 if (strstart(sym_name, "__op_param", &p)) {
258 n = strtoul(p, NULL, 10);
259 if (n >= MAX_ARGS)
260 error("too many arguments in %s", name);
261 args_present[n - 1] = 1;
262 } else {
263 fprintf(outfile, "extern char %s;\n", sym_name);
264 }
265 }
266 }
267 }
268
269 nb_args = 0;
270 while (nb_args < MAX_ARGS && args_present[nb_args])
271 nb_args++;
272 for(i = nb_args; i < MAX_ARGS; i++) {
273 if (args_present[i])
274 error("inconsistent argument numbering in %s", name);
275 }
276
277 /* output C code */
278 fprintf(outfile, "extern void %s();\n", name);
279 fprintf(outfile, "static inline void gen_%s(", name);
280 if (nb_args == 0) {
281 fprintf(outfile, "void");
282 } else {
283 for(i = 0; i < nb_args; i++) {
284 if (i != 0)
285 fprintf(outfile, ", ");
286 fprintf(outfile, "long param%d", i + 1);
287 }
288 }
289 fprintf(outfile, ")\n");
290 fprintf(outfile, "{\n");
291 fprintf(outfile, " memcpy(gen_code_ptr, &%s, %d);\n", name, copy_size);
292
293 /* patch relocations */
294 switch(e_machine) {
295 case EM_386:
296 {
297 Elf32_Rel *rel;
298 char name[256];
299 int type;
300 long addend;
301 for(i = 0, rel = relocs;i < nb_relocs; i++, rel++) {
302 if (rel->r_offset >= offset && rel->r_offset < offset + copy_size) {
303 sym_name = strtab + symtab[ELF32_R_SYM(rel->r_info)].st_name;
304 if (strstart(sym_name, "__op_param", &p)) {
305 snprintf(name, sizeof(name), "param%s", p);
306 } else {
307 snprintf(name, sizeof(name), "(long)(&%s)", sym_name);
308 }
309 type = ELF32_R_TYPE(rel->r_info);
310 addend = get32((uint32_t *)(text + rel->r_offset));
311 switch(type) {
312 case R_386_32:
313 fprintf(outfile, " *(uint32_t *)(gen_code_ptr + %ld) = %s + %ld;\n",
314 rel->r_offset - offset, name, addend);
315 break;
316 case R_386_PC32:
317 fprintf(outfile, " *(uint32_t *)(gen_code_ptr + %ld) = %s - (long)(gen_code_ptr + %ld) + %ld;\n",
318 rel->r_offset - offset, name, rel->r_offset - offset, addend);
319 break;
320 default:
321 error("unsupported i386 relocation (%d)", type);
322 }
323 }
324 }
325 }
326 break;
327 default:
328 error("unsupported CPU for relocations (%d)", e_machine);
329 }
330
331
332 fprintf(outfile, " gen_code_ptr += %d;\n", copy_size);
333 fprintf(outfile, "}\n\n");
334 }
335
336 /* load an elf object file */
337 int load_elf(const char *filename, FILE *outfile)
338 {
339 int fd;
340 Elf32_Ehdr ehdr;
341 Elf32_Shdr *sec, *shdr, *symtab_sec, *strtab_sec, *text_sec;
342 int i, j, nb_syms;
343 Elf32_Sym *symtab, *sym;
344 const char *cpu_name;
345 char *shstr, *strtab;
346 uint8_t *text;
347 void *relocs;
348 int nb_relocs, reloc_sh_type;
349
350 fd = open(filename, O_RDONLY);
351 if (fd < 0)
352 error("can't open file '%s'", filename);
353
354 /* Read ELF header. */
355 if (read(fd, &ehdr, sizeof (ehdr)) != sizeof (ehdr))
356 error("unable to read file header");
357
358 /* Check ELF identification. */
359 if (ehdr.e_ident[EI_MAG0] != ELFMAG0
360 || ehdr.e_ident[EI_MAG1] != ELFMAG1
361 || ehdr.e_ident[EI_MAG2] != ELFMAG2
362 || ehdr.e_ident[EI_MAG3] != ELFMAG3
363 || ehdr.e_ident[EI_CLASS] != ELFCLASS32
364 || ehdr.e_ident[EI_VERSION] != EV_CURRENT) {
365 error("bad ELF header");
366 }
367
368 do_swap = elf_must_swap(&ehdr);
369 if (do_swap)
370 elf_swap_ehdr(&ehdr);
371 if (ehdr.e_type != ET_REL)
372 error("ELF object file expected");
373 if (ehdr.e_version != EV_CURRENT)
374 error("Invalid ELF version");
375 e_machine = ehdr.e_machine;
376
377 /* read section headers */
378 shdr = load_data(fd, ehdr.e_shoff, ehdr.e_shnum * sizeof(Elf32_Shdr));
379 if (do_swap) {
380 for(i = 0; i < ehdr.e_shnum; i++) {
381 elf_swap_shdr(&shdr[i]);
382 }
383 }
384
385 sec = &shdr[ehdr.e_shstrndx];
386 shstr = load_data(fd, sec->sh_offset, sec->sh_size);
387
388 /* text section */
389
390 text_sec = find_elf_section(shdr, ehdr.e_shnum, shstr, ".text");
391 if (!text_sec)
392 error("could not find .text section");
393 text = load_data(fd, text_sec->sh_offset, text_sec->sh_size);
394
395 /* find text relocations, if any */
396 nb_relocs = 0;
397 relocs = NULL;
398 reloc_sh_type = 0;
399 for(i = 0; i < ehdr.e_shnum; i++) {
400 sec = &shdr[i];
401 if ((sec->sh_type == SHT_REL || sec->sh_type == SHT_RELA) &&
402 sec->sh_info == (text_sec - shdr)) {
403 reloc_sh_type = sec->sh_type;
404 relocs = load_data(fd, sec->sh_offset, sec->sh_size);
405 nb_relocs = sec->sh_size / sec->sh_entsize;
406 if (do_swap) {
407 if (sec->sh_type == SHT_REL) {
408 Elf32_Rel *rel = relocs;
409 for(j = 0, rel = relocs; j < nb_relocs; j++, rel++) {
410 swab32s(&rel->r_offset);
411 swab32s(&rel->r_info);
412 }
413 } else {
414 Elf32_Rela *rel = relocs;
415 for(j = 0, rel = relocs; j < nb_relocs; j++, rel++) {
416 swab32s(&rel->r_offset);
417 swab32s(&rel->r_info);
418 swab32s(&rel->r_addend);
419 }
420 }
421 }
422 break;
423 }
424 }
425
426 symtab_sec = find_elf_section(shdr, ehdr.e_shnum, shstr, ".symtab");
427 if (!symtab_sec)
428 error("could not find .symtab section");
429 strtab_sec = &shdr[symtab_sec->sh_link];
430
431 symtab = load_data(fd, symtab_sec->sh_offset, symtab_sec->sh_size);
432 strtab = load_data(fd, strtab_sec->sh_offset, strtab_sec->sh_size);
433
434 nb_syms = symtab_sec->sh_size / sizeof(Elf32_Sym);
435 if (do_swap) {
436 for(i = 0, sym = symtab; i < nb_syms; i++, sym++) {
437 swab32s(&sym->st_name);
438 swab32s(&sym->st_value);
439 swab32s(&sym->st_size);
440 swab16s(&sym->st_shndx);
441 }
442 }
443
444 switch(e_machine) {
445 case EM_386:
446 cpu_name = "i386";
447 break;
448 case EM_PPC:
449 cpu_name = "ppc";
450 break;
451 case EM_MIPS:
452 cpu_name = "mips";
453 break;
454 case EM_ARM:
455 cpu_name = "arm";
456 break;
457 case EM_SPARC:
458 cpu_name = "sparc";
459 break;
460 default:
461 error("unsupported CPU (e_machine=%d)", e_machine);
462 }
463
464 fprintf(outfile, "#include \"gen-%s.h\"\n\n", cpu_name);
465
466 for(i = 0, sym = symtab; i < nb_syms; i++, sym++) {
467 const char *name;
468 name = strtab + sym->st_name;
469 if (strstart(name, "op_", NULL) ||
470 strstart(name, "op1_", NULL) ||
471 strstart(name, "op2_", NULL) ||
472 strstart(name, "op3_", NULL)) {
473 #if 0
474 printf("%4d: %s pos=0x%08x len=%d\n",
475 i, name, sym->st_value, sym->st_size);
476 #endif
477 if (sym->st_shndx != (text_sec - shdr))
478 error("invalid section for opcode (0x%x)", sym->st_shndx);
479 gen_code(name, sym->st_value, sym->st_size, outfile,
480 text, relocs, nb_relocs, reloc_sh_type, symtab, strtab);
481 }
482 }
483
484 close(fd);
485 return 0;
486 }
487
488 void usage(void)
489 {
490 printf("dyngen (c) 2003 Fabrice Bellard\n"
491 "usage: dyngen [-o outfile] objfile\n"
492 "Generate a dynamic code generator from an object file\n");
493 exit(1);
494 }
495
496 int main(int argc, char **argv)
497 {
498 int c;
499 const char *filename, *outfilename;
500 FILE *outfile;
501
502 outfilename = "out.c";
503 for(;;) {
504 c = getopt(argc, argv, "ho:");
505 if (c == -1)
506 break;
507 switch(c) {
508 case 'h':
509 usage();
510 break;
511 case 'o':
512 outfilename = optarg;
513 break;
514 }
515 }
516 if (optind >= argc)
517 usage();
518 filename = argv[optind];
519 outfile = fopen(outfilename, "w");
520 if (!outfile)
521 error("could not open '%s'", outfilename);
522 load_elf(filename, outfile);
523 fclose(outfile);
524 return 0;
525 }