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view lwasm/insn_gen.c @ 577:e49d24f4a9a5
Correct bug in the object file output code leading to stack corruption
It turns out leaving a pointer to a stack allocated temporary in a
persistent data structure is not conducive to correct program operation.
Undo the export check setup in the object file output sequence so a
pointer to stack allocated memory is not left hanging when the function
returns. This seems to correct at least one mysterious crash bug, and
possibly others.
Thanks to Boisy Pitre for reporting the crash bug that led to this
discovery, as well as a previous crash bug that likely has the same
root cause.
Additional thanks to Ciaran Anscomb whose debugger wielding wizardry
revealed the exact location of this particular bit of unbrilliance.
author | William Astle <lost@l-w.ca> |
---|---|
date | Sat, 03 Aug 2024 14:30:06 -0600 |
parents | 62720ac9e28d |
children |
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/* insn_gen.c, Copyright © 2009 William Astle This file is part of LWASM. LWASM is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program. If not, see <http://www.gnu.org/licenses/>. Contains code for parsing general addressing modes (IMM+DIR+EXT+IND) */ #include <ctype.h> #include <stdlib.h> #include <lw_expr.h> #include "lwasm.h" #include "instab.h" void insn_indexed_parse_aux(asmstate_t *as, line_t *l, char **p); void insn_indexed_resolve_aux(asmstate_t *as, line_t *l, int force, int elen); void insn_indexed_emit_aux(asmstate_t *as, line_t *l); void insn_parse_indexed_aux(asmstate_t *as, line_t *l, char **p); void insn_resolve_indexed_aux(asmstate_t *as, line_t *l, int force, int elen); // "extra" is required due to the way OIM, EIM, TIM, and AIM work void insn_parse_gen_aux(asmstate_t *as, line_t *l, char **p, int elen) { char *optr2; int v1, tv; lw_expr_t s; if (!**p) { lwasm_register_error(as, l, E_OPERAND_BAD); return; } /* this is the easy case - start it [ or , means indexed */ if (**p == ',' || **p == '[') { indexed: l -> lint = -1; l -> lint2 = 1; insn_parse_indexed_aux(as, l, p); l -> minlen = OPLEN(instab[l -> insn].ops[1]) + 1 + elen; l -> maxlen = OPLEN(instab[l -> insn].ops[1]) + 3 + elen; goto out; } /* we have to parse the first expression to find if we have a comma after it */ optr2 = *p; if (**p == '<') { (*p)++; l -> lint2 = 0; if (**p == '<') { *p = optr2; goto indexed; } } // for compatibility with asxxxx // * followed by a digit, alpha, or _, or ., or ?, or another * is "f8" else if (**p == '*') { tv = *(*p + 1); if (isdigit(tv) || isalpha(tv) || tv == '_' || tv == '.' || tv == '?' || tv == '@' || tv == '*' || tv == '+' || tv == '-') { l -> lint2 = 0; (*p)++; } } else if (**p == '>') { (*p)++; l -> lint2 = 2; } else { l -> lint2 = -1; } lwasm_skip_to_next_token(l, p); s = lwasm_parse_expr(as, p); if (**p == ',') { /* we have an indexed mode here - reset and transfer control to indexing mode */ lw_expr_destroy(s); *p = optr2; goto indexed; } if (!s) { lwasm_register_error(as, l, E_OPERAND_BAD); return; } lwasm_save_expr(l, 0, s); l -> minlen = OPLEN(instab[l -> insn].ops[0]) + 1 + elen; l -> maxlen = OPLEN(instab[l -> insn].ops[2]) + 2 + elen; if (as -> output_format == OUTPUT_OBJ && l -> lint2 == -1) { l -> lint2 = 2; goto out; } if (l -> lint2 != -1) goto out; // if we have a constant now, figure out dp vs nondp if (lw_expr_istype(s, lw_expr_type_int)) { if (s -> value > 0xffff) lwasm_register_error(as, l, E_BYTE_OVERFLOW); v1 = lw_expr_intval(s); if (((v1 >> 8) & 0xff) == (l -> dpval & 0xff)) { l -> lint2 = 0; goto out; } l -> lint2 = 2; } else { int min; int max; if (lwasm_calculate_range(as, s, &min, &max) == 0) { // fprintf(stderr, "range (P) %d...%d for %s\n", min, max, lw_expr_print(s)); if (min > max) { // we don't know what to do in this case so don't do anything goto out; } min = (min >> 8) & 0xff; max = (max >> 8) & 0xff; if ((l -> dpval & 0xff) < min || (l -> dpval & 0xff) > max) { l -> lint2 = 2; goto out; } if (min == max && (l -> dpval & 0xff) == min) { l -> lint2 = 0; goto out; } // if here, we don't know if the value is in the DP or not { l -> lint2 = -1; goto out; } } } out: if (l -> lint2 != -1) { if (l -> lint2 == 0) { l -> len = OPLEN(instab[l -> insn].ops[0]) + 1 + elen; } else if (l -> lint2 == 2) { l -> len = OPLEN(instab[l -> insn].ops[2]) + 2 + elen; } else if (l -> lint2 == 1 && l -> lint != -1) { if (l -> lint == 3) l -> len = OPLEN(instab[l -> insn].ops[1]) + 1 + elen; else l -> len = OPLEN(instab[l -> insn].ops[1]) + l -> lint + 1 + elen; } } } void insn_resolve_gen_aux(asmstate_t *as, line_t *l, int force, int elen) { lw_expr_t e; if (l -> lint2 == 1) { // indexed insn_resolve_indexed_aux(as, l, force, elen); goto out; } if (l -> lint2 != -1) return; e = lwasm_fetch_expr(l, 0); lwasm_reduce_expr(as, e); if (lw_expr_istype(e, lw_expr_type_int)) { int v; v = lw_expr_intval(e); if (((v >> 8) & 0xff) == (l -> dpval & 0xff)) { l -> lint2 = 0; goto out; } l -> lint2 = 2; goto out; } else { int min; int max; if (lwasm_calculate_range(as, e, &min, &max) == 0) { // fprintf(stderr, "range (R) %d...%d for %s\n", min, max, lw_expr_print(e)); if (min > max) { // we don't know what to do in this case so don't do anything goto out; } min = (min >> 8) & 0xff; max = (max >> 8) & 0xff; if ((l -> dpval & 0xff) < min || (l -> dpval & 0xff) > max) { l -> lint2 = 2; goto out; } if (min == max && (l -> dpval & 0xff) == min) { l -> lint2 = 0; goto out; } // if here, we don't know if the value is in the DP or not { l -> lint2 = -1; goto out; } } } if (force) { l -> lint2 = 2; } out: if (l -> lint2 != -1) { if (l -> lint2 == 0) { l -> len = OPLEN(instab[l -> insn].ops[0]) + 1 + elen; } else if (l -> lint2 == 2) { l -> len = OPLEN(instab[l -> insn].ops[2]) + 2 + elen; } else if (l -> lint2 == 1 && l -> lint != -1) { if (l -> lint == 3) l -> len = OPLEN(instab[l -> insn].ops[1]) + 1 + elen; else l -> len = OPLEN(instab[l -> insn].ops[1]) + l -> lint + 1 + elen; } } } void insn_emit_gen_aux(asmstate_t *as, line_t *l, int extra) { lw_expr_t e; e = lwasm_fetch_expr(l, 0); lwasm_emitop(l, instab[l -> insn].ops[l -> lint2]); if (extra != -1) lwasm_emit(l, extra); if (l -> lint2 == 1) { if (l -> lint == 3) { int offs; if (lw_expr_istype(e, lw_expr_type_int)) { offs = lw_expr_intval(e); if ((offs >= -16 && offs <= 15) || offs >= 0xFFF0) { l -> pb |= offs & 0x1f; l -> lint = 0; } else { lwasm_register_error(as, l, E_BYTE_OVERFLOW); } } else { lwasm_register_error(as, l, E_EXPRESSION_NOT_RESOLVED); } } lwasm_emit(l, l -> pb); if (l -> lint > 0) { int i; i = lw_expr_intval(e); if (l -> lint == 1) { if (i < -128 || i > 127) lwasm_register_error(as, l, E_BYTE_OVERFLOW); } else if (l -> lint == 2 && lw_expr_istype(e, lw_expr_type_int) && CURPRAGMA(l, PRAGMA_OPERANDSIZE)) { // note that W relative and extended indirect must be 16 bits if (l -> pb != 0xAF && l -> pb != 0xB0 && l -> pb != 0x9f) { if ((i >= -128 && i <= 127) || i >= 0xFF80) { lwasm_register_error(as, l, W_OPERAND_SIZE); } } } lwasm_emitexpr(l, e, l -> lint); } l -> cycle_adj = lwasm_cycle_calc_ind(l); return; } if (l -> lint2 == 2) { lwasm_emitexpr(l, e, 2); if (CURPRAGMA(l, PRAGMA_OPERANDSIZE)) { if (instab[l -> insn].ops[2] == 0xbd || instab[l -> insn].ops[2] == 0x7e) { // check if bsr or bra could be used instead lw_expr_t e1, e2; int offs; e2 = lw_expr_build(lw_expr_type_special, lwasm_expr_linelen, l); e1 = lw_expr_build(lw_expr_type_oper, lw_expr_oper_minus, e, e2); lw_expr_destroy(e2); e2 = lw_expr_build(lw_expr_type_oper, lw_expr_oper_minus, e1, l -> addr); lw_expr_destroy(e1); lwasm_reduce_expr(as, e2); if (lw_expr_istype(e2, lw_expr_type_int)) { offs = lw_expr_intval(e2); if (offs >= -128 && offs <= 127) { lwasm_register_error(as, l, W_OPERAND_SIZE); } } lw_expr_destroy(e2); } } } else { lwasm_emitexpr(l, e, 1); } } // the various insn_gen? functions have an immediate mode of ? bits PARSEFUNC(insn_parse_gen0) { if (**p == '#') { lwasm_register_error(as, l, E_IMMEDIATE_INVALID); return; } // handle non-immediate insn_parse_gen_aux(as, l, p, 0); } RESOLVEFUNC(insn_resolve_gen0) { if (l -> len != -1) return; // handle non-immediate insn_resolve_gen_aux(as, l, force, 0); } EMITFUNC(insn_emit_gen0) { insn_emit_gen_aux(as, l, -1); } PARSEFUNC(insn_parse_gen8) { l -> genmode = 8; if (**p == '#') { lw_expr_t e; (*p)++; as -> exprwidth = 8; e = lwasm_parse_expr(as, p); as -> exprwidth = 16; if (!e) { lwasm_register_error(as, l, E_OPERAND_BAD); return; } l -> len = OPLEN(instab[l -> insn].ops[3]) + 1; l -> lint2 = 3; lwasm_save_expr(l, 0, e); return; } // handle non-immediate insn_parse_gen_aux(as, l, p, 0); if (l -> lint2 != -1) { if (l -> lint2 == 0) { l -> len = OPLEN(instab[l -> insn].ops[0]) + 1; } else if (l -> lint2 == 2) { l -> len = OPLEN(instab[l -> insn].ops[2]) + 2; } else if (l -> lint2 == 1 && l -> lint != -1) { if (l -> lint == 3) l -> len = OPLEN(instab[l -> insn].ops[1]) + 1; else l -> len = OPLEN(instab[l -> insn].ops[1]) + l -> lint + 1; } } } RESOLVEFUNC(insn_resolve_gen8) { if (l -> len != -1) return; // handle non-immediate insn_resolve_gen_aux(as, l, force, 0); } EMITFUNC(insn_emit_gen8) { if (l -> lint2 == 3) { lw_expr_t e; e = lwasm_fetch_expr(l, 0); if (lw_expr_istype(e, lw_expr_type_int)) { int i; i = lw_expr_intval(e); if (i < -128 || i > 255) { lwasm_register_error(as, l, E_BYTE_OVERFLOW); } } lwasm_emitop(l, instab[l -> insn].ops[3]); lwasm_emitexpr(l, e, 1); return; } insn_emit_gen_aux(as, l, -1); } PARSEFUNC(insn_parse_gen16) { l -> genmode = 16; if (**p == '#') { lw_expr_t e; (*p)++; e = lwasm_parse_expr(as, p); if (!e) { lwasm_register_error(as, l, E_OPERAND_BAD); return; } l -> len = OPLEN(instab[l -> insn].ops[3]) + 2; l -> lint2 = 3; lwasm_save_expr(l, 0, e); return; } // handle non-immediate insn_parse_gen_aux(as, l, p, 0); if (l -> lint2 != -1) { if (l -> lint2 == 0) { l -> len = OPLEN(instab[l -> insn].ops[0]) + 1; } else if (l -> lint2 == 2) { l -> len = OPLEN(instab[l -> insn].ops[2]) + 2; } else if (l -> lint2 == 1 && l -> lint != -1) { if (l -> lint == 3) l -> len = OPLEN(instab[l -> insn].ops[1]) + 1; else l -> len = OPLEN(instab[l -> insn].ops[1]) + l -> lint + 1; } } } RESOLVEFUNC(insn_resolve_gen16) { if (l -> len != -1) return; // handle non-immediate insn_resolve_gen_aux(as, l, force, 0); } EMITFUNC(insn_emit_gen16) { if (l -> lint2 == 3) { lw_expr_t e; e = lwasm_fetch_expr(l, 0); lwasm_emitop(l, instab[l -> insn].ops[3]); lwasm_emitexpr(l, e, 2); return; } insn_emit_gen_aux(as, l, -1); } PARSEFUNC(insn_parse_gen32) { l -> genmode = 32; if (**p == '#') { lw_expr_t e; (*p)++; e = lwasm_parse_expr(as, p); if (!e) { lwasm_register_error(as, l, E_OPERAND_BAD); return; } l -> len = OPLEN(instab[l -> insn].ops[3]) + 4; l -> lint2 = 3; lwasm_save_expr(l, 0, e); return; } // handle non-immediate insn_parse_gen_aux(as, l, p, 0); if (l -> lint2 != -1) { if (l -> lint2 == 0) { l -> len = OPLEN(instab[l -> insn].ops[0]) + 1; } else if (l -> lint2 == 2) { l -> len = OPLEN(instab[l -> insn].ops[2]) + 2; } else if (l -> lint2 == 1 && l -> lint != -1) { if (l -> lint == 3) l -> len = OPLEN(instab[l -> insn].ops[1]) + 1; else l -> len = OPLEN(instab[l -> insn].ops[1]) + l -> lint + 1; } } } RESOLVEFUNC(insn_resolve_gen32) { if (l -> len != -1) return; // handle non-immediate insn_resolve_gen_aux(as, l, force, 0); } EMITFUNC(insn_emit_gen32) { if (l -> lint2 == 3) { lw_expr_t e; e = lwasm_fetch_expr(l, 0); lwasm_emitop(l, instab[l -> insn].ops[3]); lwasm_emitexpr(l, e, 4); return; } insn_emit_gen_aux(as, l, -1); } PARSEFUNC(insn_parse_imm8) { lw_expr_t e; if (**p == '#') { (*p)++; as -> exprwidth = 8; e = lwasm_parse_expr(as, p); as -> exprwidth = 16; if (!e) { lwasm_register_error(as, l, E_OPERAND_BAD); return; } l -> len = OPLEN(instab[l -> insn].ops[0]) + 1; lwasm_save_expr(l, 0, e); } else { lwasm_register_error(as, l, E_OPERAND_BAD); } } EMITFUNC(insn_emit_imm8) { lw_expr_t e; lwasm_emitop(l, instab[l -> insn].ops[0]); e = lwasm_fetch_expr(l, 0); if (lw_expr_istype(e, lw_expr_type_int)) { int i; i = lw_expr_intval(e); if (i < -128 || i > 255) { lwasm_register_error(as, l, E_BYTE_OVERFLOW); } } lwasm_emitexpr(l, e, 1); }