x86_64-link.c

   1 #ifdef TARGET_DEFS_ONLY
   2
   3 #define EM_TCC_TARGET EM_X86_64
   4
   5 /* relocation type for 32 bit data relocation */
   6 #define R_DATA_32   R_X86_64_32S
   7 #define R_DATA_PTR  R_X86_64_64
   8 #define R_JMP_SLOT  R_X86_64_JUMP_SLOT
   9 #define R_GLOB_DAT  R_X86_64_GLOB_DAT
  10 #define R_COPY      R_X86_64_COPY
  11 #define R_RELATIVE  R_X86_64_RELATIVE
  12
  13 #define R_NUM       R_X86_64_NUM
  14
  15 #define ELF_START_ADDR 0x400000
  16 #define ELF_PAGE_SIZE  0x200000
  17
  18 #define PCRELATIVE_DLLPLT 1
  19 #define RELOCATE_DLLPLT 1
  20
  21 #else /* !TARGET_DEFS_ONLY */
  22
  23 #include "tcc.h"
  24
  25 #if !defined(ELF_OBJ_ONLY) || defined(TCC_TARGET_MACHO)
  26 /* Returns 1 for a code relocation, 0 for a data relocation. For unknown
  27    relocations, returns -1. */
  28 int code_reloc (int reloc_type)
  29 {
  30     switch (reloc_type) {
  31         case R_X86_64_32:
  32         case R_X86_64_32S:
  33         case R_X86_64_64:
  34         case R_X86_64_GOTPC32:
  35         case R_X86_64_GOTPC64:
  36         case R_X86_64_GOTPCREL:
  37         case R_X86_64_GOTPCRELX:
  38         case R_X86_64_REX_GOTPCRELX:
  39         case R_X86_64_GOTTPOFF:
  40         case R_X86_64_GOT32:
  41         case R_X86_64_GOT64:
  42         case R_X86_64_GLOB_DAT:
  43         case R_X86_64_COPY:
  44         case R_X86_64_RELATIVE:
  45         case R_X86_64_GOTOFF64:
  46             return 0;
  47
  48         case R_X86_64_PC32:
  49         case R_X86_64_PC64:
  50         case R_X86_64_PLT32:
  51         case R_X86_64_PLTOFF64:
  52         case R_X86_64_JUMP_SLOT:
  53             return 1;
  54     }
  55     return -1;
  56 }
  57
  58 /* Returns an enumerator to describe whether and when the relocation needs a
  59    GOT and/or PLT entry to be created. See tcc.h for a description of the
  60    different values. */
  61 int gotplt_entry_type (int reloc_type)
  62 {
  63     switch (reloc_type) {
  64         case R_X86_64_GLOB_DAT:
  65         case R_X86_64_JUMP_SLOT:
  66         case R_X86_64_COPY:
  67         case R_X86_64_RELATIVE:
  68             return NO_GOTPLT_ENTRY;
  69
  70         /* The following relocs wouldn't normally need GOT or PLT
  71            slots, but we need them for simplicity in the link
  72            editor part.  See our caller for comments.  */
  73         case R_X86_64_32:
  74         case R_X86_64_32S:
  75         case R_X86_64_64:
  76         case R_X86_64_PC32:
  77         case R_X86_64_PC64:
  78             return AUTO_GOTPLT_ENTRY;
  79
  80         case R_X86_64_GOTTPOFF:
  81             return BUILD_GOT_ONLY;
  82
  83         case R_X86_64_GOT32:
  84         case R_X86_64_GOT64:
  85         case R_X86_64_GOTPC32:
  86         case R_X86_64_GOTPC64:
  87         case R_X86_64_GOTOFF64:
  88         case R_X86_64_GOTPCREL:
  89         case R_X86_64_GOTPCRELX:
  90         case R_X86_64_REX_GOTPCRELX:
  91         case R_X86_64_PLT32:
  92         case R_X86_64_PLTOFF64:
  93             return ALWAYS_GOTPLT_ENTRY;
  94     }
  95
  96     return -1;
  97 }
  98
  99 #if !defined(TCC_TARGET_MACHO) || defined TCC_IS_NATIVE
 100 ST_FUNC unsigned create_plt_entry(TCCState *s1, unsigned got_offset, struct sym_attr *attr)
 101 {
 102     Section *plt = s1->plt;
 103     uint8_t *p;
 104     int modrm;
 105     unsigned plt_offset, relofs;
 106
 107     modrm = 0x25;
 108
 109     /* empty PLT: create PLT0 entry that pushes the library identifier
 110        (GOT + PTR_SIZE) and jumps to ld.so resolution routine
 111        (GOT + 2 * PTR_SIZE) */
 112     if (plt->data_offset == 0) {
 113         p = section_ptr_add(plt, 16);
 114         p[0] = 0xff; /* pushl got + PTR_SIZE */
 115         p[1] = modrm + 0x10;
 116         write32le(p + 2, PTR_SIZE);
 117         p[6] = 0xff; /* jmp *(got + PTR_SIZE * 2) */
 118         p[7] = modrm;
 119         write32le(p + 8, PTR_SIZE * 2);
 120     }
 121     plt_offset = plt->data_offset;
 122
 123     /* The PLT slot refers to the relocation entry it needs via offset.
 124        The reloc entry is created below, so its offset is the current
 125        data_offset */
 126     relofs = s1->got->reloc ? s1->got->reloc->data_offset : 0;
 127
 128     /* Jump to GOT entry where ld.so initially put the address of ip + 4 */
 129     p = section_ptr_add(plt, 16);
 130     p[0] = 0xff; /* jmp *(got + x) */
 131     p[1] = modrm;
 132     write32le(p + 2, got_offset);
 133     p[6] = 0x68; /* push $xxx */
 134     /* On x86-64, the relocation is referred to by _index_ */
 135     write32le(p + 7, relofs / sizeof (ElfW_Rel));
 136     p[11] = 0xe9; /* jmp plt_start */
 137     write32le(p + 12, -(plt->data_offset));
 138     return plt_offset;
 139 }
 140
 141 /* relocate the PLT: compute addresses and offsets in the PLT now that final
 142    address for PLT and GOT are known (see fill_program_header) */
 143 ST_FUNC void relocate_plt(TCCState *s1)
 144 {
 145     uint8_t *p, *p_end;
 146
 147     if (!s1->plt)
 148       return;
 149
 150     p = s1->plt->data;
 151     p_end = p + s1->plt->data_offset;
 152
 153     if (p < p_end) {
 154         int x = s1->got->sh_addr - s1->plt->sh_addr - 6;
 155         add32le(p + 2, x);
 156         add32le(p + 8, x - 6);
 157         p += 16;
 158         while (p < p_end) {
 159             add32le(p + 2, x + (s1->plt->data - p));
 160             p += 16;
 161         }
 162     }
 163 }
 164 #endif
 165 #endif
 166
 167 void relocate(TCCState *s1, ElfW_Rel *rel, int type, unsigned char *ptr, addr_t addr, addr_t val)
 168 {
 169     int sym_index, esym_index;
 170
 171     sym_index = ELFW(R_SYM)(rel->r_info);
 172
 173     switch (type) {
 174         case R_X86_64_64:
 175             if (s1->output_type == TCC_OUTPUT_DLL) {
 176                 esym_index = get_sym_attr(s1, sym_index, 0)->dyn_index;
 177                 qrel->r_offset = rel->r_offset;
 178                 if (esym_index) {
 179                     qrel->r_info = ELFW(R_INFO)(esym_index, R_X86_64_64);
 180                     qrel->r_addend = rel->r_addend;
 181                     qrel++;
 182                     break;
 183                 } else {
 184                     qrel->r_info = ELFW(R_INFO)(0, R_X86_64_RELATIVE);
 185                     qrel->r_addend = read64le(ptr) + val;
 186                     qrel++;
 187                 }
 188             }
 189             add64le(ptr, val);
 190             break;
 191         case R_X86_64_32:
 192         case R_X86_64_32S:
 193             if (s1->output_type == TCC_OUTPUT_DLL) {
 194                 /* XXX: this logic may depend on TCC's codegen
 195                    now TCC uses R_X86_64_32 even for a 64bit pointer */
 196                 qrel->r_offset = rel->r_offset;
 197                 qrel->r_info = ELFW(R_INFO)(0, R_X86_64_RELATIVE);
 198                 /* Use sign extension! */
 199                 qrel->r_addend = (int)read32le(ptr) + val;
 200                 qrel++;
 201             }
 202             add32le(ptr, val);
 203             break;
 204
 205         case R_X86_64_PC32:
 206             if (s1->output_type == TCC_OUTPUT_DLL) {
 207                 /* DLL relocation */
 208                 esym_index = get_sym_attr(s1, sym_index, 0)->dyn_index;
 209                 if (esym_index) {
 210                     qrel->r_offset = rel->r_offset;
 211                     qrel->r_info = ELFW(R_INFO)(esym_index, R_X86_64_PC32);
 212                     /* Use sign extension! */
 213                     qrel->r_addend = (int)read32le(ptr) + rel->r_addend;
 214                     qrel++;
 215                     break;
 216                 }
 217             }
 218             goto plt32pc32;
 219
 220         case R_X86_64_PLT32:
 221             /* fallthrough: val already holds the PLT slot address */
 222
 223         plt32pc32:
 224         {
 225             long long diff;
 226             diff = (long long)val - addr;
 227             if (diff < -2147483648LL || diff > 2147483647LL) {
 228                 tcc_error("internal error: relocation failed");
 229             }
 230             add32le(ptr, diff);
 231         }
 232             break;
 233
 234         case R_X86_64_PLTOFF64:
 235             add64le(ptr, val - s1->got->sh_addr + rel->r_addend);
 236             break;
 237
 238         case R_X86_64_PC64:
 239             if (s1->output_type == TCC_OUTPUT_DLL) {
 240                 /* DLL relocation */
 241                 esym_index = get_sym_attr(s1, sym_index, 0)->dyn_index;
 242                 if (esym_index) {
 243                     qrel->r_offset = rel->r_offset;
 244                     qrel->r_info = ELFW(R_INFO)(esym_index, R_X86_64_PC64);
 245                     qrel->r_addend = read64le(ptr) + rel->r_addend;
 246                     qrel++;
 247                     break;
 248                 }
 249             }
 250             add64le(ptr, val - addr);
 251             break;
 252
 253         case R_X86_64_GLOB_DAT:
 254         case R_X86_64_JUMP_SLOT:
 255             /* They don't need addend */
 256             write64le(ptr, val - rel->r_addend);
 257             break;
 258         case R_X86_64_GOTPCREL:
 259         case R_X86_64_GOTPCRELX:
 260         case R_X86_64_REX_GOTPCRELX:
 261             add32le(ptr, s1->got->sh_addr - addr +
 262                          get_sym_attr(s1, sym_index, 0)->got_offset - 4);
 263             break;
 264         case R_X86_64_GOTPC32:
 265             add32le(ptr, s1->got->sh_addr - addr + rel->r_addend);
 266             break;
 267         case R_X86_64_GOTPC64:
 268             add64le(ptr, s1->got->sh_addr - addr + rel->r_addend);
 269             break;
 270         case R_X86_64_GOTTPOFF:
 271             add32le(ptr, val - s1->got->sh_addr);
 272             break;
 273         case R_X86_64_GOT32:
 274             /* we load the got offset */
 275             add32le(ptr, get_sym_attr(s1, sym_index, 0)->got_offset);
 276             break;
 277         case R_X86_64_GOT64:
 278             /* we load the got offset */
 279             add64le(ptr, get_sym_attr(s1, sym_index, 0)->got_offset);
 280             break;
 281         case R_X86_64_GOTOFF64:
 282             add64le(ptr, val - s1->got->sh_addr);
 283             break;
 284         case R_X86_64_RELATIVE:
 285 #ifdef TCC_TARGET_PE
 286             add32le(ptr, val - s1->pe_imagebase);
 287 #endif
 288             /* do nothing */
 289             break;
 290     }
 291 }
 292
 293 #endif /* !TARGET_DEFS_ONLY */