| 1 | /* |
| 2 | * ia32rtools |
| 3 | * (C) notaz, 2013,2014 |
| 4 | * |
| 5 | * This work is licensed under the terms of 3-clause BSD license. |
| 6 | * See COPYING file in the top-level directory. |
| 7 | */ |
| 8 | |
| 9 | #include <stdio.h> |
| 10 | #include <stdlib.h> |
| 11 | #include <string.h> |
| 12 | |
| 13 | #include "my_assert.h" |
| 14 | #include "my_str.h" |
| 15 | #include "common.h" |
| 16 | |
| 17 | #include "protoparse.h" |
| 18 | |
| 19 | static const char *c_save_regs[] = { "ebx", "esi", "edi", "ebp" }; |
| 20 | |
| 21 | static int is_x86_reg_saved(const char *reg) |
| 22 | { |
| 23 | static const char *nosave_regs[] = { "eax", "edx", "ecx" }; |
| 24 | int nosave = 0; |
| 25 | int r; |
| 26 | |
| 27 | for (r = 0; r < ARRAY_SIZE(nosave_regs); r++) |
| 28 | if (strcmp(reg, nosave_regs[r]) == 0) |
| 29 | nosave = 1; |
| 30 | |
| 31 | return !nosave; |
| 32 | } |
| 33 | |
| 34 | // output decorated name |
| 35 | static const char *pp_to_name(const struct parsed_proto *pp) |
| 36 | { |
| 37 | static char buf[256]; |
| 38 | char atval[16]; |
| 39 | |
| 40 | if (!pp->is_fastcall && pp->argc_reg != 0) { |
| 41 | // can only be handled by __cdecl C func |
| 42 | snprintf(buf, sizeof(buf), "_%s", pp->name); |
| 43 | return buf; |
| 44 | } |
| 45 | |
| 46 | atval[0] = 0; |
| 47 | if (pp->is_stdcall) { |
| 48 | snprintf(atval, sizeof(atval), "@%d", |
| 49 | pp->argc * 4); |
| 50 | } |
| 51 | snprintf(buf, sizeof(buf), "%s%s%s", |
| 52 | pp->is_fastcall ? "@" : "_", |
| 53 | pp->name, atval); |
| 54 | |
| 55 | return buf; |
| 56 | } |
| 57 | |
| 58 | static void out_toasm_x86(FILE *f, const char *sym_out, |
| 59 | const struct parsed_proto *pp) |
| 60 | { |
| 61 | int must_save = 0; |
| 62 | int sarg_ofs = 1; // stack offset to args, in DWORDs |
| 63 | int args_repushed = 0; |
| 64 | int argc_repush; |
| 65 | const char *name; |
| 66 | int i; |
| 67 | |
| 68 | argc_repush = pp->argc; |
| 69 | if (pp->is_vararg) |
| 70 | argc_repush = ARRAY_SIZE(pp->arg); // hopefully enough? |
| 71 | |
| 72 | for (i = 0; i < pp->argc; i++) { |
| 73 | if (pp->arg[i].reg != NULL) |
| 74 | must_save |= is_x86_reg_saved(pp->arg[i].reg); |
| 75 | } |
| 76 | |
| 77 | name = pp_to_name(pp); |
| 78 | fprintf(f, ".global %s\n", name); |
| 79 | fprintf(f, "%s:\n", name); |
| 80 | |
| 81 | if (pp->argc_reg == 0 || pp->is_fastcall) { |
| 82 | fprintf(f, "\t# %s\n", |
| 83 | pp->is_fastcall ? "__fastcall" : |
| 84 | (pp->is_stdcall ? "__stdcall" : "__cdecl")); |
| 85 | fprintf(f, "\tjmp %s\n\n", sym_out); |
| 86 | return; |
| 87 | } |
| 88 | |
| 89 | if (pp->argc_stack == 0 && !must_save && !pp->is_stdcall |
| 90 | && !pp->is_vararg && !pp->has_retreg) |
| 91 | { |
| 92 | // load arg regs |
| 93 | for (i = 0; i < pp->argc; i++) { |
| 94 | fprintf(f, "\tmovl %d(%%esp), %%%s\n", |
| 95 | (i + sarg_ofs) * 4, pp->arg[i].reg); |
| 96 | } |
| 97 | fprintf(f, "\tjmp %s\n\n", sym_out); |
| 98 | return; |
| 99 | } |
| 100 | |
| 101 | // asm_stack_args | saved_regs | ra | args_from_c |
| 102 | |
| 103 | // save the regs |
| 104 | // because we don't always know what we are calling, |
| 105 | // be safe and save everything that has to be saved in __cdecl |
| 106 | for (i = 0; i < ARRAY_SIZE(c_save_regs); i++) { |
| 107 | fprintf(f, "\tpushl %%%s\n", c_save_regs[i]); |
| 108 | sarg_ofs++; |
| 109 | } |
| 110 | |
| 111 | // reconstruct arg stack for asm |
| 112 | for (i = argc_repush - 1; i >= 0; i--) { |
| 113 | if (pp->arg[i].reg == NULL) { |
| 114 | fprintf(f, "\tmovl %d(%%esp), %%eax\n", |
| 115 | (i + sarg_ofs) * 4); |
| 116 | fprintf(f, "\tpushl %%eax\n"); |
| 117 | sarg_ofs++; |
| 118 | args_repushed++; |
| 119 | } |
| 120 | } |
| 121 | |
| 122 | // load arg regs |
| 123 | for (i = 0; i < pp->argc; i++) { |
| 124 | if (pp->arg[i].reg != NULL) { |
| 125 | fprintf(f, "\tmovl %d(%%esp), %%%s\n", |
| 126 | (i + sarg_ofs) * 4, pp->arg[i].reg); |
| 127 | if (pp->arg[i].type.is_retreg) |
| 128 | fprintf(f, "\tmovl (%%%s), %%%s\n", |
| 129 | pp->arg[i].reg, pp->arg[i].reg); |
| 130 | } |
| 131 | } |
| 132 | |
| 133 | fprintf(f, "\n\t# %s\n", pp->is_stdcall ? "__stdcall" : "__cdecl"); |
| 134 | fprintf(f, "\tcall %s\n\n", sym_out); |
| 135 | |
| 136 | if (args_repushed && !pp->is_stdcall) { |
| 137 | fprintf(f, "\tadd $%d,%%esp\n", args_repushed * 4); |
| 138 | sarg_ofs -= args_repushed; |
| 139 | } |
| 140 | |
| 141 | // update the retreg regs |
| 142 | if (pp->has_retreg) { |
| 143 | for (i = 0; i < pp->argc; i++) { |
| 144 | if (pp->arg[i].type.is_retreg) { |
| 145 | fprintf(f, "\tmovl %d(%%esp), %%ecx\n" |
| 146 | "\tmovl %%%s, (%%ecx)\n", |
| 147 | (i + sarg_ofs) * 4, pp->arg[i].reg); |
| 148 | } |
| 149 | } |
| 150 | } |
| 151 | |
| 152 | // restore regs |
| 153 | for (i = ARRAY_SIZE(c_save_regs) - 1; i >= 0; i--) |
| 154 | fprintf(f, "\tpopl %%%s\n", c_save_regs[i]); |
| 155 | |
| 156 | fprintf(f, "\tret\n\n"); |
| 157 | } |
| 158 | |
| 159 | static void out_fromasm_x86(FILE *f, const char *sym, |
| 160 | const struct parsed_proto *pp) |
| 161 | { |
| 162 | int reg_ofs[ARRAY_SIZE(pp->arg)]; |
| 163 | int sarg_ofs = 1; // stack offset to args, in DWORDs |
| 164 | int saved_regs = 0; |
| 165 | int ecx_ofs = -1; |
| 166 | int edx_ofs = -1; |
| 167 | int c_is_stdcall; |
| 168 | int argc_repush; |
| 169 | int stack_args; |
| 170 | int ret64; |
| 171 | int i; |
| 172 | |
| 173 | argc_repush = pp->argc; |
| 174 | stack_args = pp->argc_stack; |
| 175 | if (pp->is_vararg) { |
| 176 | argc_repush = ARRAY_SIZE(pp->arg); // hopefully enough? |
| 177 | stack_args = argc_repush - pp->argc_reg; |
| 178 | } |
| 179 | |
| 180 | ret64 = strstr(pp->ret_type.name, "int64") != NULL; |
| 181 | |
| 182 | fprintf(f, "# %s", |
| 183 | pp->is_fastcall ? "__fastcall" : |
| 184 | (pp->is_stdcall ? "__stdcall" : "__cdecl")); |
| 185 | if (ret64) |
| 186 | fprintf(f, " ret64"); |
| 187 | if (!pp->is_fastcall && pp->argc_reg != 0) |
| 188 | fprintf(f, " +reg"); |
| 189 | |
| 190 | if (pp->is_stdcall && !pp->is_fastcall && pp->argc_reg != 0 |
| 191 | && !IS_START(sym, "sub_") && !IS_START(sym, "f_")) |
| 192 | { |
| 193 | // alias for possible .def export |
| 194 | char sym2[256]; |
| 195 | |
| 196 | snprintf(sym2, sizeof(sym2), "_%s@%d", |
| 197 | sym, pp->argc * 4); |
| 198 | fprintf(f, "\n.global %s # for .def\n", sym2); |
| 199 | fprintf(f, "%s:", sym2); |
| 200 | } |
| 201 | fprintf(f, "\n.global %s\n", sym); |
| 202 | fprintf(f, "%s:\n", sym); |
| 203 | |
| 204 | if ((pp->argc_reg == 0 || pp->is_fastcall) |
| 205 | && !IS(pp->name, "storm_491")) // wants edx save :( |
| 206 | { |
| 207 | fprintf(f, "\tjmp %s\n\n", pp_to_name(pp)); |
| 208 | return; |
| 209 | } |
| 210 | |
| 211 | c_is_stdcall = (pp->argc_reg == 0 && pp->is_stdcall); |
| 212 | |
| 213 | // at least sc sub_47B150 needs edx to be preserved |
| 214 | // int64 returns use edx:eax - no edx save |
| 215 | // we use ecx also as scratch |
| 216 | fprintf(f, "\tpushl %%ecx\n"); |
| 217 | saved_regs++; |
| 218 | sarg_ofs++; |
| 219 | ecx_ofs = sarg_ofs; |
| 220 | if (!ret64) { |
| 221 | fprintf(f, "\tpushl %%edx\n"); |
| 222 | saved_regs++; |
| 223 | sarg_ofs++; |
| 224 | edx_ofs = sarg_ofs; |
| 225 | } |
| 226 | |
| 227 | // need space for retreg args |
| 228 | if (pp->has_retreg) { |
| 229 | for (i = 0; i < pp->argc; i++) { |
| 230 | if (!pp->arg[i].type.is_retreg) |
| 231 | continue; |
| 232 | if (IS(pp->arg[i].reg, "ecx") && ecx_ofs >= 0) { |
| 233 | reg_ofs[i] = ecx_ofs; |
| 234 | continue; |
| 235 | } |
| 236 | if (IS(pp->arg[i].reg, "edx") && edx_ofs >= 0) { |
| 237 | reg_ofs[i] = edx_ofs; |
| 238 | continue; |
| 239 | } |
| 240 | fprintf(f, "\tpushl %%%s\n", pp->arg[i].reg); |
| 241 | saved_regs++; |
| 242 | sarg_ofs++; |
| 243 | reg_ofs[i] = sarg_ofs; |
| 244 | } |
| 245 | } |
| 246 | |
| 247 | // construct arg stack |
| 248 | for (i = argc_repush - 1; i >= 0; i--) { |
| 249 | if (pp->arg[i].reg == NULL) { |
| 250 | fprintf(f, "\tmovl %d(%%esp), %%ecx\n", |
| 251 | (sarg_ofs + stack_args - 1) * 4); |
| 252 | fprintf(f, "\tpushl %%ecx\n"); |
| 253 | stack_args--; |
| 254 | } |
| 255 | else { |
| 256 | const char *reg = pp->arg[i].reg; |
| 257 | if (pp->arg[i].type.is_retreg) { |
| 258 | reg = "ecx"; |
| 259 | fprintf(f, "\tlea %d(%%esp), %%ecx\n", |
| 260 | (sarg_ofs - reg_ofs[i]) * 4); |
| 261 | } |
| 262 | else if (IS(reg, "ecx")) |
| 263 | // must reload original ecx |
| 264 | fprintf(f, "\tmovl %d(%%esp), %%ecx\n", |
| 265 | (sarg_ofs - 2) * 4); |
| 266 | |
| 267 | fprintf(f, "\tpushl %%%s\n", reg); |
| 268 | } |
| 269 | sarg_ofs++; |
| 270 | } |
| 271 | |
| 272 | fprintf(f, "\n\tcall %s\n\n", pp_to_name(pp)); |
| 273 | |
| 274 | if (!c_is_stdcall && sarg_ofs > saved_regs + 1) |
| 275 | fprintf(f, "\tadd $%d,%%esp\n", |
| 276 | (sarg_ofs - (saved_regs + 1)) * 4); |
| 277 | |
| 278 | // pop retregs |
| 279 | if (pp->has_retreg) { |
| 280 | for (i = pp->argc - 1; i >= 0; i--) { |
| 281 | if (!pp->arg[i].type.is_retreg) |
| 282 | continue; |
| 283 | if (IS(pp->arg[i].reg, "ecx") && ecx_ofs >= 0) { |
| 284 | continue; |
| 285 | } |
| 286 | if (IS(pp->arg[i].reg, "edx") && edx_ofs >= 0) { |
| 287 | continue; |
| 288 | } |
| 289 | fprintf(f, "\tpopl %%%s\n", pp->arg[i].reg); |
| 290 | } |
| 291 | } |
| 292 | |
| 293 | if (!ret64) |
| 294 | fprintf(f, "\tpopl %%edx\n"); |
| 295 | fprintf(f, "\tpopl %%ecx\n"); |
| 296 | |
| 297 | if (pp->is_stdcall && pp->argc_stack) |
| 298 | fprintf(f, "\tret $%d\n\n", pp->argc_stack * 4); |
| 299 | else |
| 300 | fprintf(f, "\tret\n\n"); |
| 301 | } |
| 302 | |
| 303 | int main(int argc, char *argv[]) |
| 304 | { |
| 305 | FILE *fout, *fsyms_to, *fsyms_from, *fhdr; |
| 306 | const struct parsed_proto *pp; |
| 307 | char line[256]; |
| 308 | char sym_noat[256]; |
| 309 | char sym[256]; |
| 310 | char *p; |
| 311 | int ret = 1; |
| 312 | |
| 313 | if (argc != 5) { |
| 314 | printf("usage:\n%s <bridge.s> <toasm_symf> <fromasm_symf> <hdrf>\n", |
| 315 | argv[0]); |
| 316 | return 1; |
| 317 | } |
| 318 | |
| 319 | hdrfn = argv[4]; |
| 320 | fhdr = fopen(hdrfn, "r"); |
| 321 | my_assert_not(fhdr, NULL); |
| 322 | |
| 323 | fsyms_from = fopen(argv[3], "r"); |
| 324 | my_assert_not(fsyms_from, NULL); |
| 325 | |
| 326 | fsyms_to = fopen(argv[2], "r"); |
| 327 | my_assert_not(fsyms_to, NULL); |
| 328 | |
| 329 | fout = fopen(argv[1], "w"); |
| 330 | my_assert_not(fout, NULL); |
| 331 | |
| 332 | fprintf(fout, ".text\n\n"); |
| 333 | fprintf(fout, "# C -> asm\n\n"); |
| 334 | |
| 335 | while (fgets(line, sizeof(line), fsyms_to)) |
| 336 | { |
| 337 | next_word(sym, sizeof(sym), line); |
| 338 | if (sym[0] == 0 || sym[0] == ';' || sym[0] == '#') |
| 339 | continue; |
| 340 | |
| 341 | // IDA asm doesn't do '@' notation.. |
| 342 | strcpy(sym_noat, sym); |
| 343 | p = strchr(sym_noat, '@'); |
| 344 | if (p != NULL) |
| 345 | *p = 0; |
| 346 | |
| 347 | pp = proto_parse(fhdr, sym_noat, 0); |
| 348 | if (pp == NULL) |
| 349 | goto out; |
| 350 | |
| 351 | out_toasm_x86(fout, sym_noat, pp); |
| 352 | } |
| 353 | |
| 354 | fprintf(fout, "# asm -> C\n\n"); |
| 355 | |
| 356 | while (fgets(line, sizeof(line), fsyms_from)) |
| 357 | { |
| 358 | next_word(sym, sizeof(sym), line); |
| 359 | if (sym[0] == 0 || sym[0] == ';' || sym[0] == '#') |
| 360 | continue; |
| 361 | |
| 362 | pp = proto_parse(fhdr, sym, 0); |
| 363 | if (pp == NULL) |
| 364 | goto out; |
| 365 | |
| 366 | out_fromasm_x86(fout, sym, pp); |
| 367 | } |
| 368 | |
| 369 | ret = 0; |
| 370 | out: |
| 371 | fclose(fout); |
| 372 | fclose(fsyms_to); |
| 373 | fclose(fsyms_from); |
| 374 | fclose(fhdr); |
| 375 | if (ret) |
| 376 | remove(argv[1]); |
| 377 | |
| 378 | return ret; |
| 379 | } |