git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@15 c046a42c-6fe2-441c-8c8c-71466251a162
526 lines
15 KiB
C
526 lines
15 KiB
C
#include <stdlib.h>
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#include <stdio.h>
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#include <stdarg.h>
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#include <inttypes.h>
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#include <elf.h>
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#include <unistd.h>
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#include <fcntl.h>
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#include "thunk.h"
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/* all dynamically generated functions begin with this code */
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#define OP_PREFIX "op"
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int elf_must_swap(Elf32_Ehdr *h)
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{
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union {
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uint32_t i;
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uint8_t b[4];
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} swaptest;
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swaptest.i = 1;
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return (h->e_ident[EI_DATA] == ELFDATA2MSB) !=
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(swaptest.b[0] == 0);
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}
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void swab16s(uint16_t *p)
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{
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*p = bswap16(*p);
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}
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void swab32s(uint32_t *p)
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{
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*p = bswap32(*p);
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}
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void swab64s(uint32_t *p)
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{
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*p = bswap64(*p);
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}
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void elf_swap_ehdr(Elf32_Ehdr *h)
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{
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swab16s(&h->e_type); /* Object file type */
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swab16s(&h-> e_machine); /* Architecture */
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swab32s(&h-> e_version); /* Object file version */
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swab32s(&h-> e_entry); /* Entry point virtual address */
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swab32s(&h-> e_phoff); /* Program header table file offset */
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swab32s(&h-> e_shoff); /* Section header table file offset */
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swab32s(&h-> e_flags); /* Processor-specific flags */
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swab16s(&h-> e_ehsize); /* ELF header size in bytes */
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swab16s(&h-> e_phentsize); /* Program header table entry size */
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swab16s(&h-> e_phnum); /* Program header table entry count */
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swab16s(&h-> e_shentsize); /* Section header table entry size */
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swab16s(&h-> e_shnum); /* Section header table entry count */
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swab16s(&h-> e_shstrndx); /* Section header string table index */
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}
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void elf_swap_shdr(Elf32_Shdr *h)
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{
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swab32s(&h-> sh_name); /* Section name (string tbl index) */
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swab32s(&h-> sh_type); /* Section type */
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swab32s(&h-> sh_flags); /* Section flags */
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swab32s(&h-> sh_addr); /* Section virtual addr at execution */
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swab32s(&h-> sh_offset); /* Section file offset */
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swab32s(&h-> sh_size); /* Section size in bytes */
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swab32s(&h-> sh_link); /* Link to another section */
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swab32s(&h-> sh_info); /* Additional section information */
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swab32s(&h-> sh_addralign); /* Section alignment */
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swab32s(&h-> sh_entsize); /* Entry size if section holds table */
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}
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void elf_swap_phdr(Elf32_Phdr *h)
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{
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swab32s(&h->p_type); /* Segment type */
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swab32s(&h->p_offset); /* Segment file offset */
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swab32s(&h->p_vaddr); /* Segment virtual address */
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swab32s(&h->p_paddr); /* Segment physical address */
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swab32s(&h->p_filesz); /* Segment size in file */
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swab32s(&h->p_memsz); /* Segment size in memory */
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swab32s(&h->p_flags); /* Segment flags */
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swab32s(&h->p_align); /* Segment alignment */
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}
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int do_swap;
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int e_machine;
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uint16_t get16(uint16_t *p)
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{
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uint16_t val;
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val = *p;
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if (do_swap)
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val = bswap16(val);
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return val;
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}
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uint32_t get32(uint32_t *p)
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{
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uint32_t val;
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val = *p;
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if (do_swap)
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val = bswap32(val);
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return val;
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}
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void put16(uint16_t *p, uint16_t val)
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{
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if (do_swap)
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val = bswap16(val);
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*p = val;
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}
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void put32(uint32_t *p, uint32_t val)
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{
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if (do_swap)
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val = bswap32(val);
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*p = val;
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}
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void __attribute__((noreturn)) error(const char *fmt, ...)
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{
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va_list ap;
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va_start(ap, fmt);
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fprintf(stderr, "dyngen: ");
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vfprintf(stderr, fmt, ap);
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fprintf(stderr, "\n");
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va_end(ap);
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exit(1);
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}
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Elf32_Shdr *find_elf_section(Elf32_Shdr *shdr, int shnum, const char *shstr,
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const char *name)
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{
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int i;
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const char *shname;
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Elf32_Shdr *sec;
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for(i = 0; i < shnum; i++) {
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sec = &shdr[i];
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if (!sec->sh_name)
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continue;
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shname = shstr + sec->sh_name;
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if (!strcmp(shname, name))
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return sec;
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}
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return NULL;
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}
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void *load_data(int fd, long offset, unsigned int size)
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{
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char *data;
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data = malloc(size);
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if (!data)
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return NULL;
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lseek(fd, offset, SEEK_SET);
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if (read(fd, data, size) != size) {
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free(data);
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return NULL;
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}
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return data;
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}
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int strstart(const char *str, const char *val, const char **ptr)
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{
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const char *p, *q;
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p = str;
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q = val;
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while (*q != '\0') {
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if (*p != *q)
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return 0;
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p++;
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q++;
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}
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if (ptr)
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*ptr = p;
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return 1;
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}
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#define MAX_ARGS 3
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/* generate op code */
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void gen_code(const char *name, unsigned long offset, unsigned long size,
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FILE *outfile, uint8_t *text, void *relocs, int nb_relocs, int reloc_sh_type,
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Elf32_Sym *symtab, char *strtab)
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{
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int copy_size = 0;
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uint8_t *p_start, *p_end;
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int nb_args, i;
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uint8_t args_present[MAX_ARGS];
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const char *sym_name, *p;
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/* compute exact size excluding return instruction */
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p_start = text + offset;
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p_end = p_start + size;
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switch(e_machine) {
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case EM_386:
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{
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uint8_t *p;
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p = p_end - 1;
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/* find ret */
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while (p > p_start && *p != 0xc3)
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p--;
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/* skip double ret */
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if (p > p_start && p[-1] == 0xc3)
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p--;
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if (p == p_start)
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error("empty code for %s", name);
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copy_size = p - p_start;
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}
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break;
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case EM_PPC:
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{
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uint8_t *p;
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p = (void *)(p_end - 4);
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/* find ret */
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while (p > p_start && get32((uint32_t *)p) != 0x4e800020)
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p -= 4;
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/* skip double ret */
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if (p > p_start && get32((uint32_t *)(p - 4)) == 0x4e800020)
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p -= 4;
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if (p == p_start)
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error("empty code for %s", name);
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copy_size = p - p_start;
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}
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break;
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default:
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error("unsupported CPU (%d)", e_machine);
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}
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/* compute the number of arguments by looking at the relocations */
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for(i = 0;i < MAX_ARGS; i++)
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args_present[i] = 0;
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if (reloc_sh_type == SHT_REL) {
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Elf32_Rel *rel;
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int n;
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for(i = 0, rel = relocs;i < nb_relocs; i++, rel++) {
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if (rel->r_offset >= offset && rel->r_offset < offset + copy_size) {
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sym_name = strtab + symtab[ELF32_R_SYM(rel->r_info)].st_name;
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if (strstart(sym_name, "__op_param", &p)) {
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n = strtoul(p, NULL, 10);
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if (n >= MAX_ARGS)
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error("too many arguments in %s", name);
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args_present[n - 1] = 1;
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} else {
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fprintf(outfile, "extern char %s;\n", sym_name);
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}
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}
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}
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} else {
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Elf32_Rela *rel;
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int n;
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for(i = 0, rel = relocs;i < nb_relocs; i++, rel++) {
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if (rel->r_offset >= offset && rel->r_offset < offset + copy_size) {
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sym_name = strtab + symtab[ELF32_R_SYM(rel->r_info)].st_name;
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if (strstart(sym_name, "__op_param", &p)) {
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n = strtoul(p, NULL, 10);
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if (n >= MAX_ARGS)
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error("too many arguments in %s", name);
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args_present[n - 1] = 1;
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} else {
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fprintf(outfile, "extern char %s;\n", sym_name);
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}
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}
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}
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}
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nb_args = 0;
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while (nb_args < MAX_ARGS && args_present[nb_args])
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nb_args++;
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for(i = nb_args; i < MAX_ARGS; i++) {
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if (args_present[i])
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error("inconsistent argument numbering in %s", name);
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}
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/* output C code */
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fprintf(outfile, "extern void %s();\n", name);
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fprintf(outfile, "static inline void gen_%s(", name);
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if (nb_args == 0) {
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fprintf(outfile, "void");
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} else {
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for(i = 0; i < nb_args; i++) {
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if (i != 0)
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fprintf(outfile, ", ");
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fprintf(outfile, "long param%d", i + 1);
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}
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}
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fprintf(outfile, ")\n");
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fprintf(outfile, "{\n");
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fprintf(outfile, " memcpy(gen_code_ptr, &%s, %d);\n", name, copy_size);
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/* patch relocations */
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switch(e_machine) {
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case EM_386:
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{
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Elf32_Rel *rel;
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char name[256];
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int type;
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long addend;
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for(i = 0, rel = relocs;i < nb_relocs; i++, rel++) {
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if (rel->r_offset >= offset && rel->r_offset < offset + copy_size) {
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sym_name = strtab + symtab[ELF32_R_SYM(rel->r_info)].st_name;
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if (strstart(sym_name, "__op_param", &p)) {
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snprintf(name, sizeof(name), "param%s", p);
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} else {
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snprintf(name, sizeof(name), "(long)(&%s)", sym_name);
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}
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type = ELF32_R_TYPE(rel->r_info);
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addend = get32((uint32_t *)(text + rel->r_offset));
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switch(type) {
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case R_386_32:
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fprintf(outfile, " *(uint32_t *)(gen_code_ptr + %ld) = %s + %ld;\n",
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rel->r_offset - offset, name, addend);
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break;
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case R_386_PC32:
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fprintf(outfile, " *(uint32_t *)(gen_code_ptr + %ld) = %s - (long)(gen_code_ptr + %ld) + %ld;\n",
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rel->r_offset - offset, name, rel->r_offset - offset, addend);
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break;
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default:
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error("unsupported i386 relocation (%d)", type);
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}
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}
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}
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}
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break;
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default:
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error("unsupported CPU for relocations (%d)", e_machine);
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}
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fprintf(outfile, " gen_code_ptr += %d;\n", copy_size);
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fprintf(outfile, "}\n\n");
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}
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/* load an elf object file */
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int load_elf(const char *filename, FILE *outfile)
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{
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int fd;
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Elf32_Ehdr ehdr;
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Elf32_Shdr *sec, *shdr, *symtab_sec, *strtab_sec, *text_sec;
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int i, j, nb_syms;
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Elf32_Sym *symtab, *sym;
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const char *cpu_name;
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char *shstr, *strtab;
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uint8_t *text;
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void *relocs;
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int nb_relocs, reloc_sh_type;
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fd = open(filename, O_RDONLY);
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if (fd < 0)
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error("can't open file '%s'", filename);
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/* Read ELF header. */
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if (read(fd, &ehdr, sizeof (ehdr)) != sizeof (ehdr))
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error("unable to read file header");
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/* Check ELF identification. */
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if (ehdr.e_ident[EI_MAG0] != ELFMAG0
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|| ehdr.e_ident[EI_MAG1] != ELFMAG1
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|| ehdr.e_ident[EI_MAG2] != ELFMAG2
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|| ehdr.e_ident[EI_MAG3] != ELFMAG3
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|| ehdr.e_ident[EI_CLASS] != ELFCLASS32
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|| ehdr.e_ident[EI_VERSION] != EV_CURRENT) {
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error("bad ELF header");
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}
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do_swap = elf_must_swap(&ehdr);
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if (do_swap)
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elf_swap_ehdr(&ehdr);
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if (ehdr.e_type != ET_REL)
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error("ELF object file expected");
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if (ehdr.e_version != EV_CURRENT)
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error("Invalid ELF version");
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e_machine = ehdr.e_machine;
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/* read section headers */
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shdr = load_data(fd, ehdr.e_shoff, ehdr.e_shnum * sizeof(Elf32_Shdr));
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if (do_swap) {
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for(i = 0; i < ehdr.e_shnum; i++) {
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elf_swap_shdr(&shdr[i]);
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}
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}
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sec = &shdr[ehdr.e_shstrndx];
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shstr = load_data(fd, sec->sh_offset, sec->sh_size);
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/* text section */
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text_sec = find_elf_section(shdr, ehdr.e_shnum, shstr, ".text");
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if (!text_sec)
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error("could not find .text section");
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text = load_data(fd, text_sec->sh_offset, text_sec->sh_size);
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/* find text relocations, if any */
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nb_relocs = 0;
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relocs = NULL;
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reloc_sh_type = 0;
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for(i = 0; i < ehdr.e_shnum; i++) {
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sec = &shdr[i];
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if ((sec->sh_type == SHT_REL || sec->sh_type == SHT_RELA) &&
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sec->sh_info == (text_sec - shdr)) {
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reloc_sh_type = sec->sh_type;
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relocs = load_data(fd, sec->sh_offset, sec->sh_size);
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nb_relocs = sec->sh_size / sec->sh_entsize;
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if (do_swap) {
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if (sec->sh_type == SHT_REL) {
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Elf32_Rel *rel = relocs;
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for(j = 0, rel = relocs; j < nb_relocs; j++, rel++) {
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swab32s(&rel->r_offset);
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swab32s(&rel->r_info);
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}
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} else {
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Elf32_Rela *rel = relocs;
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for(j = 0, rel = relocs; j < nb_relocs; j++, rel++) {
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swab32s(&rel->r_offset);
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swab32s(&rel->r_info);
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swab32s(&rel->r_addend);
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}
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}
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}
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break;
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}
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}
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symtab_sec = find_elf_section(shdr, ehdr.e_shnum, shstr, ".symtab");
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if (!symtab_sec)
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error("could not find .symtab section");
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strtab_sec = &shdr[symtab_sec->sh_link];
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symtab = load_data(fd, symtab_sec->sh_offset, symtab_sec->sh_size);
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strtab = load_data(fd, strtab_sec->sh_offset, strtab_sec->sh_size);
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nb_syms = symtab_sec->sh_size / sizeof(Elf32_Sym);
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if (do_swap) {
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for(i = 0, sym = symtab; i < nb_syms; i++, sym++) {
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swab32s(&sym->st_name);
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swab32s(&sym->st_value);
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swab32s(&sym->st_size);
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swab16s(&sym->st_shndx);
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}
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}
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switch(e_machine) {
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case EM_386:
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cpu_name = "i386";
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break;
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case EM_PPC:
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cpu_name = "ppc";
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break;
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case EM_MIPS:
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cpu_name = "mips";
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break;
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case EM_ARM:
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cpu_name = "arm";
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break;
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case EM_SPARC:
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cpu_name = "sparc";
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break;
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default:
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error("unsupported CPU (e_machine=%d)", e_machine);
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}
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fprintf(outfile, "#include \"gen-%s.h\"\n\n", cpu_name);
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for(i = 0, sym = symtab; i < nb_syms; i++, sym++) {
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const char *name;
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name = strtab + sym->st_name;
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if (strstart(name, "op_", NULL) ||
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strstart(name, "op1_", NULL) ||
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strstart(name, "op2_", NULL) ||
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strstart(name, "op3_", NULL)) {
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#if 0
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printf("%4d: %s pos=0x%08x len=%d\n",
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i, name, sym->st_value, sym->st_size);
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#endif
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if (sym->st_shndx != (text_sec - shdr))
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error("invalid section for opcode (0x%x)", sym->st_shndx);
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gen_code(name, sym->st_value, sym->st_size, outfile,
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text, relocs, nb_relocs, reloc_sh_type, symtab, strtab);
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}
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}
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close(fd);
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return 0;
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}
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void usage(void)
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{
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printf("dyngen (c) 2003 Fabrice Bellard\n"
|
|
"usage: dyngen [-o outfile] objfile\n"
|
|
"Generate a dynamic code generator from an object file\n");
|
|
exit(1);
|
|
}
|
|
|
|
int main(int argc, char **argv)
|
|
{
|
|
int c;
|
|
const char *filename, *outfilename;
|
|
FILE *outfile;
|
|
|
|
outfilename = "out.c";
|
|
for(;;) {
|
|
c = getopt(argc, argv, "ho:");
|
|
if (c == -1)
|
|
break;
|
|
switch(c) {
|
|
case 'h':
|
|
usage();
|
|
break;
|
|
case 'o':
|
|
outfilename = optarg;
|
|
break;
|
|
}
|
|
}
|
|
if (optind >= argc)
|
|
usage();
|
|
filename = argv[optind];
|
|
outfile = fopen(outfilename, "w");
|
|
if (!outfile)
|
|
error("could not open '%s'", outfilename);
|
|
load_elf(filename, outfile);
|
|
fclose(outfile);
|
|
return 0;
|
|
}
|