** try to find last instruction before 'lastpc' that modified register 'reg' */
| 383 | ** try to find last instruction before 'lastpc' that modified register 'reg' |
| 384 | */ |
| 385 | static int findsetreg (Proto *p, int lastpc, int reg) { |
| 386 | int pc; |
| 387 | int setreg = -1; /* keep last instruction that changed 'reg' */ |
| 388 | int jmptarget = 0; /* any code before this address is conditional */ |
| 389 | for (pc = 0; pc < lastpc; pc++) { |
| 390 | Instruction i = p->code[pc]; |
| 391 | OpCode op = GET_OPCODE(i); |
| 392 | int a = GETARG_A(i); |
| 393 | switch (op) { |
| 394 | case OP_LOADNIL: { |
| 395 | int b = GETARG_B(i); |
| 396 | if (a <= reg && reg <= a + b) /* set registers from 'a' to 'a+b' */ |
| 397 | setreg = filterpc(pc, jmptarget); |
| 398 | break; |
| 399 | } |
| 400 | case OP_TFORCALL: { |
| 401 | if (reg >= a + 2) /* affect all regs above its base */ |
| 402 | setreg = filterpc(pc, jmptarget); |
| 403 | break; |
| 404 | } |
| 405 | case OP_CALL: |
| 406 | case OP_TAILCALL: { |
| 407 | if (reg >= a) /* affect all registers above base */ |
| 408 | setreg = filterpc(pc, jmptarget); |
| 409 | break; |
| 410 | } |
| 411 | case OP_JMP: { |
| 412 | int b = GETARG_sBx(i); |
| 413 | int dest = pc + 1 + b; |
| 414 | /* jump is forward and do not skip 'lastpc'? */ |
| 415 | if (pc < dest && dest <= lastpc) { |
| 416 | if (dest > jmptarget) |
| 417 | jmptarget = dest; /* update 'jmptarget' */ |
| 418 | } |
| 419 | break; |
| 420 | } |
| 421 | default: |
| 422 | if (testAMode(op) && reg == a) /* any instruction that set A */ |
| 423 | setreg = filterpc(pc, jmptarget); |
| 424 | break; |
| 425 | } |
| 426 | } |
| 427 | return setreg; |
| 428 | } |
| 429 | |
| 430 | |
| 431 | static const char *getobjname (Proto *p, int lastpc, int reg, |
no test coverage detected