/* * Value handling * * Copyright (C) 2006-2007 Peter Johnson * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND OTHER CONTRIBUTORS ``AS IS'' * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR OTHER CONTRIBUTORS BE * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE * POSSIBILITY OF SUCH DAMAGE. */ #include "util.h" #include "libyasm-stdint.h" #include "coretype.h" #include "bitvect.h" #include "errwarn.h" #include "intnum.h" #include "floatnum.h" #include "expr.h" #include "value.h" #include "symrec.h" #include "bytecode.h" #include "section.h" #include "arch.h" void yasm_value_initialize(/*@out@*/ yasm_value *value, /*@null@*/ /*@kept@*/ yasm_expr *e, unsigned int size) { value->abs = e; value->rel = NULL; value->wrt = NULL; value->seg_of = 0; value->rshift = 0; value->curpos_rel = 0; value->ip_rel = 0; value->jump_target = 0; value->section_rel = 0; value->no_warn = 0; value->sign = 0; value->size = size; } void yasm_value_init_sym(/*@out@*/ yasm_value *value, /*@null@*/ yasm_symrec *sym, unsigned int size) { value->abs = NULL; value->rel = sym; value->wrt = NULL; value->seg_of = 0; value->rshift = 0; value->curpos_rel = 0; value->ip_rel = 0; value->jump_target = 0; value->section_rel = 0; value->no_warn = 0; value->sign = 0; value->size = size; } void yasm_value_init_copy(yasm_value *value, const yasm_value *orig) { value->abs = orig->abs ? yasm_expr_copy(orig->abs) : NULL; value->rel = orig->rel; value->wrt = orig->wrt; value->seg_of = orig->seg_of; value->rshift = orig->rshift; value->curpos_rel = orig->curpos_rel; value->ip_rel = orig->ip_rel; value->jump_target = orig->jump_target; value->section_rel = orig->section_rel; value->no_warn = orig->no_warn; value->sign = orig->sign; value->size = orig->size; } void yasm_value_delete(yasm_value *value) { if (value->abs) yasm_expr_destroy(value->abs); value->abs = NULL; value->rel = NULL; } void yasm_value_set_curpos_rel(yasm_value *value, yasm_bytecode *bc, unsigned int ip_rel) { value->curpos_rel = 1; value->ip_rel = ip_rel; /* In order for us to correctly output curpos-relative values, we must * have a relative portion of the value. If one doesn't exist, point * to a custom absolute symbol. */ if (!value->rel) { yasm_object *object = yasm_section_get_object(yasm_bc_get_section(bc)); value->rel = yasm_symtab_abs_sym(object->symtab); } } static int value_finalize_scan(yasm_value *value, yasm_expr *e, /*@null@*/ yasm_bytecode *expr_precbc, int ssym_not_ok) { int i; /*@dependent@*/ yasm_section *sect; /*@dependent@*/ /*@null@*/ yasm_bytecode *precbc; unsigned long shamt; /* for SHR */ /* Yes, this has a maximum upper bound on 32 terms, based on an * "insane number of terms" (and ease of implementation) WAG. * The right way to do this would be a stack-based alloca, but that's * not ISO C. We really don't want to malloc here as this function is * hit a lot! * * This is a bitmask to keep things small, as this is a recursive * routine and we don't want to eat up stack space. */ unsigned long used; /* for ADD */ /* Thanks to this running after a simplify, we don't need to iterate * down through IDENTs or handle SUB. * * We scan for a single symrec, gathering info along the way. After * we've found the symrec, we keep scanning but error if we find * another one. We pull out the single symrec and any legal operations * performed on it. * * Also, if we find a float anywhere, we don't allow mixing of a single * symrec with it. */ switch (e->op) { case YASM_EXPR_ADD: /* Okay for single symrec anywhere in expr. * Check for single symrec anywhere. * Handle symrec-symrec by checking for (-1*symrec) * and symrec term pairs (where both symrecs are in the same * segment). */ if (e->numterms > 32) yasm__fatal(N_("expression on line %d has too many add terms;" " internal limit of 32"), e->line); used = 0; for (i=0; inumterms; i++) { int j; yasm_expr *sube; yasm_intnum *intn; yasm_symrec *sym; /*@dependent@*/ yasm_section *sect2; /*@dependent@*/ /*@null@*/ yasm_bytecode *precbc2; /* First look for an (-1*symrec) term */ if (e->terms[i].type != YASM_EXPR_EXPR) continue; sube = e->terms[i].data.expn; if (sube->op != YASM_EXPR_MUL || sube->numterms != 2) { /* recurse instead */ if (value_finalize_scan(value, sube, expr_precbc, ssym_not_ok)) return 1; continue; } if (sube->terms[0].type == YASM_EXPR_INT && sube->terms[1].type == YASM_EXPR_SYM) { intn = sube->terms[0].data.intn; sym = sube->terms[1].data.sym; } else if (sube->terms[0].type == YASM_EXPR_SYM && sube->terms[1].type == YASM_EXPR_INT) { sym = sube->terms[0].data.sym; intn = sube->terms[1].data.intn; } else { if (value_finalize_scan(value, sube, expr_precbc, ssym_not_ok)) return 1; continue; } if (!yasm_intnum_is_neg1(intn)) { if (value_finalize_scan(value, sube, expr_precbc, ssym_not_ok)) return 1; continue; } /* Look for the same symrec term; even if both are external, * they should cancel out. */ for (j=0; jnumterms; j++) { if (e->terms[j].type == YASM_EXPR_SYM && e->terms[j].data.sym == sym && (used & (1<terms[i].type = YASM_EXPR_INT; e->terms[i].data.intn = yasm_intnum_create_uint(0); e->terms[j].type = YASM_EXPR_INT; e->terms[j].data.intn = yasm_intnum_create_uint(0); break; /* stop looking */ } } if (j != e->numterms) continue; if (!yasm_symrec_get_label(sym, &precbc)) { if (value_finalize_scan(value, sube, expr_precbc, ssym_not_ok)) return 1; continue; } sect2 = yasm_bc_get_section(precbc); /* Now look for a unused symrec term in the same segment */ for (j=0; jnumterms; j++) { if (e->terms[j].type == YASM_EXPR_SYM && yasm_symrec_get_label(e->terms[j].data.sym, &precbc2) && (sect = yasm_bc_get_section(precbc2)) && sect == sect2 && (used & (1<numterms && !value->curpos_rel && (yasm_symrec_is_curpos(sym) || (expr_precbc && sect2 == yasm_bc_get_section(expr_precbc)))) { for (j=0; jnumterms; j++) { if (e->terms[j].type == YASM_EXPR_SYM && !yasm_symrec_get_equ(e->terms[j].data.sym) && !yasm_symrec_is_special(e->terms[j].data.sym) && (used & (1<rel || ssym_not_ok) return 1; value->rel = e->terms[j].data.sym; value->curpos_rel = 1; if (yasm_symrec_is_curpos(sym)) { /* Replace both symrec portions with 0 */ yasm_expr_destroy(sube); e->terms[i].type = YASM_EXPR_INT; e->terms[i].data.intn = yasm_intnum_create_uint(0); e->terms[j].type = YASM_EXPR_INT; e->terms[j].data.intn = yasm_intnum_create_uint(0); } else { /* Replace positive portion with curpos */ yasm_object *object = yasm_section_get_object(sect2); yasm_symtab *symtab = object->symtab; e->terms[j].data.sym = yasm_symtab_define_curpos (symtab, ".", expr_precbc, e->line); } break; /* stop looking */ } } } if (j == e->numterms) return 1; /* We didn't find a match! */ } /* Look for unmatched symrecs. If we've already found one or * we don't WANT to find one, error out. */ for (i=0; inumterms; i++) { if (e->terms[i].type == YASM_EXPR_SYM && (used & (1<rel || ssym_not_ok) return 1; value->rel = e->terms[i].data.sym; /* and replace with 0 */ e->terms[i].type = YASM_EXPR_INT; e->terms[i].data.intn = yasm_intnum_create_uint(0); } } break; case YASM_EXPR_SHR: /* Okay for single symrec in LHS and constant on RHS. * Single symrecs are not okay on RHS. * If RHS is non-constant, don't allow single symrec on LHS. * XXX: should rshift be an expr instead?? */ /* Check for single sym on LHS */ if (e->terms[0].type != YASM_EXPR_SYM) break; /* If we already have a sym, we can't take another one */ if (value->rel || ssym_not_ok) return 1; /* RHS must be a positive integer */ if (e->terms[1].type != YASM_EXPR_INT) return 1; /* can't shift sym by non-constant integer */ shamt = yasm_intnum_get_uint(e->terms[1].data.intn); if ((shamt + value->rshift) > YASM_VALUE_RSHIFT_MAX) return 1; /* total shift would be too large */ /* Update value */ value->rshift += shamt; value->rel = e->terms[0].data.sym; /* Replace symbol with 0 */ e->terms[0].type = YASM_EXPR_INT; e->terms[0].data.intn = yasm_intnum_create_uint(0); /* Just leave SHR in place */ break; case YASM_EXPR_SEG: /* Okay for single symrec (can only be done once). * Not okay for anything BUT a single symrec as an immediate * child. */ if (e->terms[0].type != YASM_EXPR_SYM) return 1; if (value->seg_of) return 1; /* multiple SEG not legal */ value->seg_of = 1; if (value->rel || ssym_not_ok) return 1; /* got a relative portion somewhere else? */ value->rel = e->terms[0].data.sym; /* replace with ident'ed 0 */ e->op = YASM_EXPR_IDENT; e->terms[0].type = YASM_EXPR_INT; e->terms[0].data.intn = yasm_intnum_create_uint(0); break; case YASM_EXPR_WRT: /* Okay for single symrec in LHS and either a register or single * symrec (as an immediate child) on RHS. * If a single symrec on RHS, can only be done once. * WRT reg is left in expr for arch to look at. */ /* Handle RHS */ switch (e->terms[1].type) { case YASM_EXPR_SYM: if (value->wrt) return 1; value->wrt = e->terms[1].data.sym; /* and drop the WRT portion */ e->op = YASM_EXPR_IDENT; e->numterms = 1; break; case YASM_EXPR_REG: break; /* ignore */ default: return 1; } /* Handle LHS */ switch (e->terms[0].type) { case YASM_EXPR_SYM: if (value->rel || ssym_not_ok) return 1; value->rel = e->terms[0].data.sym; /* and replace with 0 */ e->terms[0].type = YASM_EXPR_INT; e->terms[0].data.intn = yasm_intnum_create_uint(0); break; case YASM_EXPR_EXPR: /* recurse */ return value_finalize_scan(value, e->terms[0].data.expn, expr_precbc, ssym_not_ok); default: break; /* ignore */ } break; default: /* Single symrec not allowed anywhere */ for (i=0; inumterms; i++) { switch (e->terms[i].type) { case YASM_EXPR_SYM: return 1; case YASM_EXPR_EXPR: /* recurse */ return value_finalize_scan(value, e->terms[i].data.expn, expr_precbc, 1); default: break; } } break; } return 0; } int yasm_value_finalize_expr(yasm_value *value, yasm_expr *e, yasm_bytecode *precbc, unsigned int size) { if (!e) { yasm_value_initialize(value, NULL, size); return 0; } yasm_value_initialize(value, e, size); return yasm_value_finalize(value, precbc); } int yasm_value_finalize(yasm_value *value, yasm_bytecode *precbc) { if (!value->abs) return 0; value->abs = yasm_expr__level_tree(value->abs, 1, 1, 0, 0, NULL, NULL); /* quit early if there was an issue in simplify() */ if (yasm_error_occurred()) return 1; /* Strip top-level AND masking to an all-1s mask the same size * of the value size. This allows forced avoidance of overflow warnings. */ if (value->abs->op == YASM_EXPR_AND) { int term; /* Calculate 1<size); yasm_intnum_calc(mask, YASM_EXPR_SHL, mask_tmp); yasm_intnum_set_uint(mask_tmp, 1); yasm_intnum_calc(mask, YASM_EXPR_SUB, mask_tmp); yasm_intnum_destroy(mask_tmp); /* Walk terms and delete matching masks */ for (term=value->abs->numterms-1; term>=0; term--) { if (value->abs->terms[term].type == YASM_EXPR_INT && yasm_intnum_compare(value->abs->terms[term].data.intn, mask) == 0) { /* Delete the intnum */ yasm_intnum_destroy(value->abs->terms[term].data.intn); /* Slide everything to its right over by 1 */ if (term != value->abs->numterms-1) /* if it wasn't last.. */ memmove(&value->abs->terms[term], &value->abs->terms[term+1], (value->abs->numterms-1-term)* sizeof(yasm_expr__item)); /* Update numterms */ value->abs->numterms--; /* Indicate warnings have been disabled */ value->no_warn = 1; } } if (value->abs->numterms == 1) value->abs->op = YASM_EXPR_IDENT; yasm_intnum_destroy(mask); } /* Handle trivial (IDENT) cases immediately */ if (value->abs->op == YASM_EXPR_IDENT) { switch (value->abs->terms[0].type) { case YASM_EXPR_INT: if (yasm_intnum_is_zero(value->abs->terms[0].data.intn)) { yasm_expr_destroy(value->abs); value->abs = NULL; } return 0; case YASM_EXPR_REG: case YASM_EXPR_FLOAT: return 0; case YASM_EXPR_SYM: value->rel = value->abs->terms[0].data.sym; yasm_expr_destroy(value->abs); value->abs = NULL; return 0; case YASM_EXPR_EXPR: /* Bring up lower values. */ while (value->abs->op == YASM_EXPR_IDENT && value->abs->terms[0].type == YASM_EXPR_EXPR) { yasm_expr *sube = value->abs->terms[0].data.expn; yasm_xfree(value->abs); value->abs = sube; } break; default: yasm_internal_error(N_("unexpected expr term type")); } } if (value_finalize_scan(value, value->abs, precbc, 0)) return 1; value->abs = yasm_expr__level_tree(value->abs, 1, 1, 0, 0, NULL, NULL); /* Simplify 0 in abs to NULL */ if (value->abs->op == YASM_EXPR_IDENT && value->abs->terms[0].type == YASM_EXPR_INT && yasm_intnum_is_zero(value->abs->terms[0].data.intn)) { yasm_expr_destroy(value->abs); value->abs = NULL; } return 0; } yasm_intnum * yasm_value_get_intnum(yasm_value *value, yasm_bytecode *bc, int calc_bc_dist) { /*@dependent@*/ /*@null@*/ yasm_intnum *intn = NULL; /*@only@*/ yasm_intnum *outval; int sym_local; if (value->abs) { /* Handle integer expressions, if non-integer or too complex, return * NULL. */ intn = yasm_expr_get_intnum(&value->abs, calc_bc_dist); if (!intn) return NULL; } if (value->rel) { /* If relative portion is not in bc section, return NULL. * Otherwise get the relative portion's offset. */ /*@dependent@*/ yasm_bytecode *rel_prevbc; unsigned long dist; if (!bc) return NULL; /* Can't calculate relative value */ sym_local = yasm_symrec_get_label(value->rel, &rel_prevbc); if (value->wrt || value->seg_of || value->section_rel || !sym_local) return NULL; /* we can't handle SEG, WRT, or external symbols */ if (rel_prevbc->section != bc->section) return NULL; /* not in this section */ if (!value->curpos_rel) return NULL; /* not PC-relative */ /* Calculate value relative to current assembly position */ dist = yasm_bc_next_offset(rel_prevbc); if (dist < bc->offset) { outval = yasm_intnum_create_uint(bc->offset - dist); yasm_intnum_calc(outval, YASM_EXPR_NEG, NULL); } else { dist -= bc->offset; outval = yasm_intnum_create_uint(dist); } if (value->rshift > 0) { /*@only@*/ yasm_intnum *shamt = yasm_intnum_create_uint((unsigned long)value->rshift); yasm_intnum_calc(outval, YASM_EXPR_SHR, shamt); yasm_intnum_destroy(shamt); } /* Add in absolute portion */ if (intn) yasm_intnum_calc(outval, YASM_EXPR_ADD, intn); return outval; } if (intn) return yasm_intnum_copy(intn); /* No absolute or relative portions: output 0 */ return yasm_intnum_create_uint(0); } int yasm_value_output_basic(yasm_value *value, /*@out@*/ unsigned char *buf, size_t destsize, yasm_bytecode *bc, int warn, yasm_arch *arch) { /*@dependent@*/ /*@null@*/ yasm_intnum *intn = NULL; /*@only@*/ yasm_intnum *outval; int sym_local; int retval = 1; unsigned int valsize = value->size; if (value->no_warn) warn = 0; if (value->abs) { /* Handle floating point expressions */ if (!value->rel && value->abs->op == YASM_EXPR_IDENT && value->abs->terms[0].type == YASM_EXPR_FLOAT) { if (yasm_arch_floatnum_tobytes(arch, value->abs->terms[0].data.flt, buf, destsize, valsize, 0, warn)) return -1; else return 1; } /* Check for complex float expressions */ if (yasm_expr__contains(value->abs, YASM_EXPR_FLOAT)) { yasm_error_set(YASM_ERROR_FLOATING_POINT, N_("floating point expression too complex")); return -1; } /* Handle normal integer expressions */ intn = yasm_expr_get_intnum(&value->abs, 1); if (!intn) { /* Second try before erroring: yasm_expr_get_intnum doesn't handle * SEG:OFF, so try simplifying out any to just the OFF portion, * then getting the intnum again. */ yasm_expr *seg = yasm_expr_extract_deep_segoff(&value->abs); if (seg) yasm_expr_destroy(seg); intn = yasm_expr_get_intnum(&value->abs, 1); } if (!intn) { /* Still don't have an integer! */ yasm_error_set(YASM_ERROR_TOO_COMPLEX, N_("expression too complex")); return -1; } } /* Adjust warn for signed/unsigned integer warnings */ if (warn != 0) warn = value->sign ? -1 : 1; if (value->rel) { /* If relative portion is not in bc section, don't try to handle it * here. Otherwise get the relative portion's offset. */ /*@dependent@*/ yasm_bytecode *rel_prevbc; unsigned long dist; sym_local = yasm_symrec_get_label(value->rel, &rel_prevbc); if (value->wrt || value->seg_of || value->section_rel || !sym_local) return 0; /* we can't handle SEG, WRT, or external symbols */ if (rel_prevbc->section != bc->section) return 0; /* not in this section */ if (!value->curpos_rel) return 0; /* not PC-relative */ /* Calculate value relative to current assembly position */ dist = yasm_bc_next_offset(rel_prevbc); if (dist < bc->offset) { outval = yasm_intnum_create_uint(bc->offset - dist); yasm_intnum_calc(outval, YASM_EXPR_NEG, NULL); } else { dist -= bc->offset; outval = yasm_intnum_create_uint(dist); } if (value->rshift > 0) { /*@only@*/ yasm_intnum *shamt = yasm_intnum_create_uint((unsigned long)value->rshift); yasm_intnum_calc(outval, YASM_EXPR_SHR, shamt); yasm_intnum_destroy(shamt); } /* Add in absolute portion */ if (intn) yasm_intnum_calc(outval, YASM_EXPR_ADD, intn); /* Output! */ if (yasm_arch_intnum_tobytes(arch, outval, buf, destsize, valsize, 0, bc, warn)) retval = -1; yasm_intnum_destroy(outval); return retval; } if (value->seg_of || value->rshift || value->curpos_rel || value->ip_rel || value->section_rel) return 0; /* We can't handle this with just an absolute */ if (intn) { /* Output just absolute portion */ if (yasm_arch_intnum_tobytes(arch, intn, buf, destsize, valsize, 0, bc, warn)) retval = -1; } else { /* No absolute or relative portions: output 0 */ outval = yasm_intnum_create_uint(0); if (yasm_arch_intnum_tobytes(arch, outval, buf, destsize, valsize, 0, bc, warn)) retval = -1; yasm_intnum_destroy(outval); } return retval; } void yasm_value_print(const yasm_value *value, FILE *f, int indent_level) { fprintf(f, "%*s%u-bit, %ssigned", indent_level, "", value->size, value->sign ? "" : "un"); fprintf(f, "%*sAbsolute portion=", indent_level, ""); yasm_expr_print(value->abs, f); fprintf(f, "\n"); if (value->rel) { fprintf(f, "%*sRelative to=%s%s\n", indent_level, "", value->seg_of ? "SEG " : "", yasm_symrec_get_name(value->rel)); if (value->wrt) fprintf(f, "%*s(With respect to=%s)\n", indent_level, "", yasm_symrec_get_name(value->wrt)); if (value->rshift > 0) fprintf(f, "%*s(Right shifted by=%u)\n", indent_level, "", value->rshift); if (value->curpos_rel) fprintf(f, "%*s(Relative to current position)\n", indent_level, ""); if (value->ip_rel) fprintf(f, "%*s(IP-relative)\n", indent_level, ""); if (value->jump_target) fprintf(f, "%*s(Jump target)\n", indent_level, ""); if (value->section_rel) fprintf(f, "%*s(Section-relative)\n", indent_level, ""); if (value->no_warn) fprintf(f, "%*s(Overflow warnings disabled)\n", indent_level, ""); } }