11f5207bJohn Levon/*
21f5207bJohn Levon * Copyright (C) 2006 Dan Carpenter.
31f5207bJohn Levon *
41f5207bJohn Levon * This program is free software; you can redistribute it and/or
51f5207bJohn Levon * modify it under the terms of the GNU General Public License
61f5207bJohn Levon * as published by the Free Software Foundation; either version 2
71f5207bJohn Levon * of the License, or (at your option) any later version.
81f5207bJohn Levon *
91f5207bJohn Levon * This program is distributed in the hope that it will be useful,
101f5207bJohn Levon * but WITHOUT ANY WARRANTY; without even the implied warranty of
111f5207bJohn Levon * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
121f5207bJohn Levon * GNU General Public License for more details.
131f5207bJohn Levon *
141f5207bJohn Levon * You should have received a copy of the GNU General Public License
151f5207bJohn Levon * along with this program; if not, see http://www.gnu.org/copyleft/gpl.txt
161f5207bJohn Levon */
171f5207bJohn Levon
181f5207bJohn Levon/*
191f5207bJohn Levon * Miscellaneous helper functions.
201f5207bJohn Levon */
211f5207bJohn Levon
221f5207bJohn Levon#include <stdlib.h>
231f5207bJohn Levon#include <stdio.h>
241f5207bJohn Levon#include "allocate.h"
251f5207bJohn Levon#include "smatch.h"
261f5207bJohn Levon#include "smatch_extra.h"
271f5207bJohn Levon#include "smatch_slist.h"
281f5207bJohn Levon
291f5207bJohn Levon#define VAR_LEN 512
301f5207bJohn Levon
311f5207bJohn Levonchar *alloc_string(const char *str)
321f5207bJohn Levon{
331f5207bJohn Levon	char *tmp;
341f5207bJohn Levon
351f5207bJohn Levon	if (!str)
361f5207bJohn Levon		return NULL;
371f5207bJohn Levon	tmp = malloc(strlen(str) + 1);
381f5207bJohn Levon	strcpy(tmp, str);
391f5207bJohn Levon	return tmp;
401f5207bJohn Levon}
411f5207bJohn Levon
42c85f09cJohn Levonchar *alloc_string_newline(const char *str)
43c85f09cJohn Levon{
44c85f09cJohn Levon	char *tmp;
45c85f09cJohn Levon	int len;
46c85f09cJohn Levon
47c85f09cJohn Levon	if (!str)
48c85f09cJohn Levon		return NULL;
49c85f09cJohn Levon	len = strlen(str);
50c85f09cJohn Levon	tmp = malloc(len + 2);
51c85f09cJohn Levon	snprintf(tmp, len + 2, "%s\n", str);
52c85f09cJohn Levon	return tmp;
53c85f09cJohn Levon}
54c85f09cJohn Levon
551f5207bJohn Levonvoid free_string(char *str)
561f5207bJohn Levon{
571f5207bJohn Levon	free(str);
581f5207bJohn Levon}
591f5207bJohn Levon
601f5207bJohn Levonvoid remove_parens(char *str)
611f5207bJohn Levon{
621f5207bJohn Levon	char *src, *dst;
631f5207bJohn Levon
641f5207bJohn Levon	dst = src = str;
651f5207bJohn Levon	while (*src != '\0') {
661f5207bJohn Levon		if (*src == '(' || *src == ')') {
671f5207bJohn Levon			src++;
681f5207bJohn Levon			continue;
691f5207bJohn Levon		}
701f5207bJohn Levon		*dst++ = *src++;
711f5207bJohn Levon	}
721f5207bJohn Levon	*dst = *src;
731f5207bJohn Levon}
741f5207bJohn Levon
751f5207bJohn Levonstruct smatch_state *alloc_state_num(int num)
761f5207bJohn Levon{
771f5207bJohn Levon	struct smatch_state *state;
781f5207bJohn Levon	static char buff[256];
791f5207bJohn Levon
801f5207bJohn Levon	state = __alloc_smatch_state(0);
811f5207bJohn Levon	snprintf(buff, 255, "%d", num);
821f5207bJohn Levon	buff[255] = '\0';
831f5207bJohn Levon	state->name = alloc_string(buff);
841f5207bJohn Levon	state->data = INT_PTR(num);
851f5207bJohn Levon	return state;
861f5207bJohn Levon}
871f5207bJohn Levon
881f5207bJohn Levonstruct smatch_state *alloc_state_str(const char *name)
891f5207bJohn Levon{
901f5207bJohn Levon	struct smatch_state *state;
911f5207bJohn Levon
921f5207bJohn Levon	state = __alloc_smatch_state(0);
931f5207bJohn Levon	state->name = alloc_string(name);
941f5207bJohn Levon	return state;
951f5207bJohn Levon}
961f5207bJohn Levon
97efe51d0John Levonstruct smatch_state *merge_str_state(struct smatch_state *s1, struct smatch_state *s2)
98efe51d0John Levon{
99efe51d0John Levon	if (!s1->name || !s2->name)
100efe51d0John Levon		return &merged;
101efe51d0John Levon	if (strcmp(s1->name, s2->name) == 0)
102efe51d0John Levon		return s1;
103efe51d0John Levon	return &merged;
104efe51d0John Levon}
105efe51d0John Levon
1061f5207bJohn Levonstruct smatch_state *alloc_state_expr(struct expression *expr)
1071f5207bJohn Levon{
1081f5207bJohn Levon	struct smatch_state *state;
1091f5207bJohn Levon	char *name;
1101f5207bJohn Levon
1111f5207bJohn Levon	expr = strip_expr(expr);
1121f5207bJohn Levon	name = expr_to_str(expr);
113efe51d0John Levon	if (!name)
114efe51d0John Levon		return NULL;
115efe51d0John Levon
116efe51d0John Levon	state = __alloc_smatch_state(0);
1171f5207bJohn Levon	state->name = alloc_sname(name);
1181f5207bJohn Levon	free_string(name);
1191f5207bJohn Levon	state->data = expr;
1201f5207bJohn Levon	return state;
1211f5207bJohn Levon}
1221f5207bJohn Levon
1231f5207bJohn Levonvoid append(char *dest, const char *data, int buff_len)
1241f5207bJohn Levon{
1251f5207bJohn Levon	strncat(dest, data, buff_len - strlen(dest) - 1);
1261f5207bJohn Levon}
1271f5207bJohn Levon
1281f5207bJohn Levon/*
1291f5207bJohn Levon * If you have "foo(a, b, 1);" then use
1301f5207bJohn Levon * get_argument_from_call_expr(expr, 0) to return the expression for
1311f5207bJohn Levon * a.  Yes, it does start counting from 0.
1321f5207bJohn Levon */
1331f5207bJohn Levonstruct expression *get_argument_from_call_expr(struct expression_list *args,
1341f5207bJohn Levon					       int num)
1351f5207bJohn Levon{
1361f5207bJohn Levon	struct expression *expr;
1371f5207bJohn Levon	int i = 0;
1381f5207bJohn Levon
1391f5207bJohn Levon	if (!args)
1401f5207bJohn Levon		return NULL;
1411f5207bJohn Levon
1421f5207bJohn Levon	FOR_EACH_PTR(args, expr) {
1431f5207bJohn Levon		if (i == num)
1441f5207bJohn Levon			return expr;
1451f5207bJohn Levon		i++;
1461f5207bJohn Levon	} END_FOR_EACH_PTR(expr);
1471f5207bJohn Levon	return NULL;
1481f5207bJohn Levon}
1491f5207bJohn Levon
1506523a3aJohn Levonstruct expression *get_array_expr(struct expression *expr)
1511f5207bJohn Levon{
1521f5207bJohn Levon	struct expression *parent;
1531f5207bJohn Levon	struct symbol *type;
1541f5207bJohn Levon
1551f5207bJohn Levon	if (expr->type != EXPR_BINOP || expr->op != '+')
1561f5207bJohn Levon		return NULL;
1571f5207bJohn Levon
1581f5207bJohn Levon	type = get_type(expr->left);
1591f5207bJohn Levon	if (!type)
1601f5207bJohn Levon		return NULL;
1611f5207bJohn Levon	if (type->type == SYM_ARRAY)
1621f5207bJohn Levon		return expr->left;
1631f5207bJohn Levon	if (type->type != SYM_PTR)
1641f5207bJohn Levon		return NULL;
1651f5207bJohn Levon
1661f5207bJohn Levon	parent = expr_get_parent_expr(expr);
1671f5207bJohn Levon	if (!parent)  /* Sometimes we haven't set up the ->parent yet. FIXME!! */
1681f5207bJohn Levon		return expr->left;
1691f5207bJohn Levon	if (parent->type == EXPR_PREOP && parent->op == '*')
1701f5207bJohn Levon		return expr->left;
1711f5207bJohn Levon
1721f5207bJohn Levon	return NULL;
1731f5207bJohn Levon}
1741f5207bJohn Levon
1751f5207bJohn Levonstatic void __get_variable_from_expr(struct symbol **sym_ptr, char *buf,
1761f5207bJohn Levon				     struct expression *expr, int len,
1776523a3aJohn Levon				     int *complicated)
1781f5207bJohn Levon{
1791f5207bJohn Levon	if (!expr) {
1801f5207bJohn Levon		/* can't happen on valid code */
1811f5207bJohn Levon		*complicated = 1;
1821f5207bJohn Levon		return;
1831f5207bJohn Levon	}
1841f5207bJohn Levon
1851f5207bJohn Levon	switch (expr->type) {
1861f5207bJohn Levon	case EXPR_DEREF: {
1871f5207bJohn Levon		struct expression *deref;
1881f5207bJohn Levon		int op;
1891f5207bJohn Levon
1901f5207bJohn Levon		deref = expr->deref;
1911f5207bJohn Levon		op = deref->op;
192efe51d0John Levon		if (deref->type == EXPR_PREOP && op == '*') {
1931f5207bJohn Levon			struct expression *unop = strip_expr(deref->unop);
1941f5207bJohn Levon
1951f5207bJohn Levon			if (unop->type == EXPR_PREOP && unop->op == '&') {
1961f5207bJohn Levon				deref = unop->unop;
1971f5207bJohn Levon				op = '.';
1981f5207bJohn Levon			} else {
199efe51d0John Levon				if (!is_pointer(deref) && !is_pointer(deref->unop))
2001f5207bJohn Levon					op = '.';
201efe51d0John Levon				deref = deref->unop;
2021f5207bJohn Levon			}
2031f5207bJohn Levon		}
2041f5207bJohn Levon
2056523a3aJohn Levon		__get_variable_from_expr(sym_ptr, buf, deref, len, complicated);
2061f5207bJohn Levon
2071f5207bJohn Levon		if (op == '*')
2081f5207bJohn Levon			append(buf, "->", len);
2091f5207bJohn Levon		else
2101f5207bJohn Levon			append(buf, ".", len);
2111f5207bJohn Levon
2121f5207bJohn Levon		if (expr->member)
2131f5207bJohn Levon			append(buf, expr->member->name, len);
2141f5207bJohn Levon		else
2151f5207bJohn Levon			append(buf, "unknown_member", len);
2161f5207bJohn Levon
2171f5207bJohn Levon		return;
2181f5207bJohn Levon	}
2191f5207bJohn Levon	case EXPR_SYMBOL:
2201f5207bJohn Levon		if (expr->symbol_name)
2211f5207bJohn Levon			append(buf, expr->symbol_name->name, len);
2221f5207bJohn Levon		if (sym_ptr) {
2231f5207bJohn Levon			if (*sym_ptr)
2241f5207bJohn Levon				*complicated = 1;
2251f5207bJohn Levon			*sym_ptr = expr->symbol;
2261f5207bJohn Levon		}
2271f5207bJohn Levon		return;
2281f5207bJohn Levon	case EXPR_PREOP: {
2291f5207bJohn Levon		const char *tmp;
2301f5207bJohn Levon
2311f5207bJohn Levon		if (get_expression_statement(expr)) {
2321f5207bJohn Levon			*complicated = 2;
2331f5207bJohn Levon			return;
2341f5207bJohn Levon		}
2351f5207bJohn Levon
2361f5207bJohn Levon		if (expr->op == '(') {
2376523a3aJohn Levon			if (expr->unop->type != EXPR_SYMBOL)
2381f5207bJohn Levon				append(buf, "(", len);
2391f5207bJohn Levon		} else if (expr->op != '*' || !get_array_expr(expr->unop)) {
2401f5207bJohn Levon			tmp = show_special(expr->op);
2411f5207bJohn Levon			append(buf, tmp, len);
2421f5207bJohn Levon		}
2431f5207bJohn Levon		__get_variable_from_expr(sym_ptr, buf, expr->unop,
2446523a3aJohn Levon						 len, complicated);
2451f5207bJohn Levon
2466523a3aJohn Levon		if (expr->op == '(' && expr->unop->type != EXPR_SYMBOL)
2471f5207bJohn Levon			append(buf, ")", len);
2481f5207bJohn Levon
2491f5207bJohn Levon		if (expr->op == SPECIAL_DECREMENT ||
2506523a3aJohn Levon		    expr->op == SPECIAL_INCREMENT)
2511f5207bJohn Levon			*complicated = 1;
2521f5207bJohn Levon
2531f5207bJohn Levon		return;
2541f5207bJohn Levon	}
2551f5207bJohn Levon	case EXPR_POSTOP: {
2561f5207bJohn Levon		const char *tmp;
2571f5207bJohn Levon
2581f5207bJohn Levon		__get_variable_from_expr(sym_ptr, buf, expr->unop,
2596523a3aJohn Levon						 len, complicated);
2601f5207bJohn Levon		tmp = show_special(expr->op);
2611f5207bJohn Levon		append(buf, tmp, len);
2621f5207bJohn Levon
2631f5207bJohn Levon		if (expr->op == SPECIAL_DECREMENT || expr->op == SPECIAL_INCREMENT)
2641f5207bJohn Levon			*complicated = 1;
2651f5207bJohn Levon		return;
2661f5207bJohn Levon	}
2671f5207bJohn Levon	case EXPR_ASSIGNMENT:
2681f5207bJohn Levon	case EXPR_COMPARE:
2691f5207bJohn Levon	case EXPR_LOGICAL:
2701f5207bJohn Levon	case EXPR_BINOP: {
2711f5207bJohn Levon		char tmp[10];
2721f5207bJohn Levon		struct expression *array_expr;
2731f5207bJohn Levon
2741f5207bJohn Levon		*complicated = 1;
2751f5207bJohn Levon		array_expr = get_array_expr(expr);
2761f5207bJohn Levon		if (array_expr) {
2776523a3aJohn Levon			__get_variable_from_expr(sym_ptr, buf, array_expr, len, complicated);
2781f5207bJohn Levon			append(buf, "[", len);
2791f5207bJohn Levon		} else {
2806523a3aJohn Levon			__get_variable_from_expr(sym_ptr, buf, expr->left, len, complicated);
2811f5207bJohn Levon			snprintf(tmp, sizeof(tmp), " %s ", show_special(expr->op));
2821f5207bJohn Levon			append(buf, tmp, len);
2831f5207bJohn Levon		}
2846523a3aJohn Levon		__get_variable_from_expr(NULL, buf, expr->right, len, complicated);
2851f5207bJohn Levon		if (array_expr)
2861f5207bJohn Levon			append(buf, "]", len);
2871f5207bJohn Levon		return;
2881f5207bJohn Levon	}
2891f5207bJohn Levon	case EXPR_VALUE: {
290c85f09cJohn Levon		sval_t sval = {};
2911f5207bJohn Levon		char tmp[25];
2921f5207bJohn Levon
2931f5207bJohn Levon		*complicated = 1;
294c85f09cJohn Levon		if (!get_value(expr, &sval))
295c85f09cJohn Levon			return;
296c85f09cJohn Levon		snprintf(tmp, 25, "%s", sval_to_numstr(sval));
2971f5207bJohn Levon		append(buf, tmp, len);
2981f5207bJohn Levon		return;
2991f5207bJohn Levon	}
3005a0e240John Levon	case EXPR_FVALUE: {
3015a0e240John Levon		sval_t sval = {};
3025a0e240John Levon		char tmp[25];
3035a0e240John Levon
3045a0e240John Levon		*complicated = 1;
3055a0e240John Levon		if (!get_value(expr, &sval))
3065a0e240John Levon			return;
3075a0e240John Levon		snprintf(tmp, 25, "%s", sval_to_numstr(sval));
3085a0e240John Levon		append(buf, tmp, len);
3095a0e240John Levon		return;
3105a0e240John Levon	}
3111f5207bJohn Levon	case EXPR_STRING:
3121f5207bJohn Levon		append(buf, "\"", len);
3131f5207bJohn Levon		if (expr->string)
3141f5207bJohn Levon			append(buf, expr->string->data, len);
3151f5207bJohn Levon		append(buf, "\"", len);
3161f5207bJohn Levon		return;
3171f5207bJohn Levon	case EXPR_CALL: {
3181f5207bJohn Levon		struct expression *tmp;
3191f5207bJohn Levon		int i;
3201f5207bJohn Levon
3211f5207bJohn Levon		*complicated = 1;
3226523a3aJohn Levon		__get_variable_from_expr(NULL, buf, expr->fn, len, complicated);
3231f5207bJohn Levon		append(buf, "(", len);
3241f5207bJohn Levon		i = 0;
3251f5207bJohn Levon		FOR_EACH_PTR(expr->args, tmp) {
3261f5207bJohn Levon			if (i++)
3271f5207bJohn Levon				append(buf, ", ", len);
3286523a3aJohn Levon			__get_variable_from_expr(NULL, buf, tmp, len, complicated);
3291f5207bJohn Levon		} END_FOR_EACH_PTR(tmp);
3301f5207bJohn Levon		append(buf, ")", len);
3311f5207bJohn Levon		return;
3321f5207bJohn Levon	}
3331f5207bJohn Levon	case EXPR_CAST:
3341f5207bJohn Levon	case EXPR_FORCE_CAST:
3351f5207bJohn Levon		__get_variable_from_expr(sym_ptr, buf,
3361f5207bJohn Levon					 expr->cast_expression, len,
3376523a3aJohn Levon					 complicated);
3381f5207bJohn Levon		return;
3391f5207bJohn Levon	case EXPR_SIZEOF: {
3401f5207bJohn Levon		sval_t sval;
3411f5207bJohn Levon		int size;
3421f5207bJohn Levon		char tmp[25];
3431f5207bJohn Levon
3441f5207bJohn Levon		if (expr->cast_type && get_base_type(expr->cast_type)) {
3451f5207bJohn Levon			size = type_bytes(get_base_type(expr->cast_type));
3461f5207bJohn Levon			snprintf(tmp, 25, "%d", size);
3471f5207bJohn Levon			append(buf, tmp, len);
3481f5207bJohn Levon		} else if (get_value(expr, &sval)) {
3491f5207bJohn Levon			snprintf(tmp, 25, "%s", sval_to_str(sval));
3501f5207bJohn Levon			append(buf, tmp, len);
3511f5207bJohn Levon		}
3521f5207bJohn Levon		return;
3531f5207bJohn Levon	}
3541f5207bJohn Levon	case EXPR_IDENTIFIER:
3551f5207bJohn Levon		*complicated = 1;
3561f5207bJohn Levon		if (expr->expr_ident)
3571f5207bJohn Levon			append(buf, expr->expr_ident->name, len);
3581f5207bJohn Levon		return;
3596523a3aJohn Levon	case EXPR_SELECT:
3606523a3aJohn Levon	case EXPR_CONDITIONAL:
3611f5207bJohn Levon		*complicated = 1;
3626523a3aJohn Levon		append(buf, "(", len);
3636523a3aJohn Levon		__get_variable_from_expr(NULL, buf, expr->conditional, len, complicated);
3646523a3aJohn Levon		append(buf, ") ?", len);
3656523a3aJohn Levon		if (expr->cond_true)
3666523a3aJohn Levon			__get_variable_from_expr(NULL, buf, expr->cond_true, len, complicated);
3676523a3aJohn Levon		append(buf, ":", len);
3686523a3aJohn Levon		__get_variable_from_expr(NULL, buf, expr->cond_false, len, complicated);
3696523a3aJohn Levon		return;
3706523a3aJohn Levon	default: {
3716523a3aJohn Levon			char tmp[64];
3726523a3aJohn Levon
3736523a3aJohn Levon			snprintf(tmp, sizeof(tmp), "$expr_%p(%d)", expr, expr->type);
3746523a3aJohn Levon			append(buf, tmp, len);
3756523a3aJohn Levon			*complicated = 1;
3766523a3aJohn Levon		}
3771f5207bJohn Levon		return;
3781f5207bJohn Levon	}
3791f5207bJohn Levon}
3801f5207bJohn Levon
3811f5207bJohn Levonstruct expr_str_cache_results {
3821f5207bJohn Levon	struct expression *expr;
3831f5207bJohn Levon	char str[VAR_LEN];
3841f5207bJohn Levon	struct symbol *sym;
3851f5207bJohn Levon	int complicated;
3861f5207bJohn Levon};
3871f5207bJohn Levon
3881f5207bJohn Levonstatic void get_variable_from_expr(struct symbol **sym_ptr, char *buf,
3891f5207bJohn Levon				     struct expression *expr, int len,
3906523a3aJohn Levon				     int *complicated)
3911f5207bJohn Levon{
3921f5207bJohn Levon	static struct expr_str_cache_results cached[8];
3931f5207bJohn Levon	struct symbol *tmp_sym = NULL;
3941f5207bJohn Levon	static int idx;
3951f5207bJohn Levon	int i;
3961f5207bJohn Levon
3971f5207bJohn Levon	for (i = 0; i < ARRAY_SIZE(cached); i++) {
3986523a3aJohn Levon		if (expr == cached[i].expr) {
3991f5207bJohn Levon			strncpy(buf, cached[i].str, len);
4001f5207bJohn Levon			if (sym_ptr)
4011f5207bJohn Levon				*sym_ptr = cached[i].sym;
4021f5207bJohn Levon			*complicated = cached[i].complicated;
4031f5207bJohn Levon			return;
4041f5207bJohn Levon		}
4051f5207bJohn Levon	}
4061f5207bJohn Levon
4076523a3aJohn Levon	__get_variable_from_expr(&tmp_sym, buf, expr, len, complicated);
4081f5207bJohn Levon	if (sym_ptr)
4091f5207bJohn Levon		*sym_ptr = tmp_sym;
4101f5207bJohn Levon
4116523a3aJohn Levon	if (expr->smatch_flags & Tmp)
4126523a3aJohn Levon		return;
4136523a3aJohn Levon
4141f5207bJohn Levon	cached[idx].expr = expr;
4151f5207bJohn Levon	strncpy(cached[idx].str, buf, VAR_LEN);
4161f5207bJohn Levon	cached[idx].sym = tmp_sym;
4171f5207bJohn Levon	cached[idx].complicated = *complicated;
4181f5207bJohn Levon
4191f5207bJohn Levon	idx = (idx + 1) % ARRAY_SIZE(cached);
4201f5207bJohn Levon}
4211f5207bJohn Levon
4221f5207bJohn Levon/*
4231f5207bJohn Levon * This is returns a stylized "c looking" representation of the
4241f5207bJohn Levon * variable name.
4251f5207bJohn Levon *
4261f5207bJohn Levon * It uses the same buffer every time so you have to save the result
4271f5207bJohn Levon * yourself if you want to keep it.
4281f5207bJohn Levon *
4291f5207bJohn Levon */
4301f5207bJohn Levon
4311f5207bJohn Levonchar *expr_to_str_sym(struct expression *expr, struct symbol **sym_ptr)
4321f5207bJohn Levon{
4331f5207bJohn Levon	static char var_name[VAR_LEN];
4341f5207bJohn Levon	int complicated = 0;
4351f5207bJohn Levon
4361f5207bJohn Levon	if (sym_ptr)
4371f5207bJohn Levon		*sym_ptr = NULL;
4381f5207bJohn Levon	var_name[0] = '\0';
4391f5207bJohn Levon
4401f5207bJohn Levon	if (!expr)
4411f5207bJohn Levon		return NULL;
4421f5207bJohn Levon	get_variable_from_expr(sym_ptr, var_name, expr, sizeof(var_name),
4436523a3aJohn Levon			       &complicated);
4441f5207bJohn Levon	if (complicated < 2)
4451f5207bJohn Levon		return alloc_string(var_name);
4461f5207bJohn Levon	else
4471f5207bJohn Levon		return NULL;
4481f5207bJohn Levon}
4491f5207bJohn Levon
4501f5207bJohn Levonchar *expr_to_str(struct expression *expr)
4511f5207bJohn Levon{
4521f5207bJohn Levon	return expr_to_str_sym(expr, NULL);
4531f5207bJohn Levon}
4541f5207bJohn Levon
4551f5207bJohn Levon/*
4561f5207bJohn Levon * get_variable_from_expr_simple() only returns simple variables.
4571f5207bJohn Levon * If it's a complicated variable like a->foo[x] instead of just 'a->foo'
4581f5207bJohn Levon * then it returns NULL.
4591f5207bJohn Levon */
4601f5207bJohn Levonchar *expr_to_var_sym(struct expression *expr,
4611f5207bJohn Levon				    struct symbol **sym_ptr)
4621f5207bJohn Levon{
4631f5207bJohn Levon	static char var_name[VAR_LEN];
4641f5207bJohn Levon	int complicated = 0;
4651f5207bJohn Levon
4661f5207bJohn Levon	if (sym_ptr)
4671f5207bJohn Levon		*sym_ptr = NULL;
4681f5207bJohn Levon	var_name[0] = '\0';
4691f5207bJohn Levon
4701f5207bJohn Levon	if (!expr)
4711f5207bJohn Levon		return NULL;
4721f5207bJohn Levon	expr = strip_expr(expr);
4731f5207bJohn Levon	get_variable_from_expr(sym_ptr, var_name, expr, sizeof(var_name),
4746523a3aJohn Levon			       &complicated);
4751f5207bJohn Levon
4761f5207bJohn Levon	if (complicated) {
4771f5207bJohn Levon		if (sym_ptr)
4781f5207bJohn Levon			*sym_ptr = NULL;
4791f5207bJohn Levon		return NULL;
4801f5207bJohn Levon	}
4811f5207bJohn Levon	return alloc_string(var_name);
4821f5207bJohn Levon}
4831f5207bJohn Levon
4841f5207bJohn Levonchar *expr_to_var(struct expression *expr)
4851f5207bJohn Levon{
4861f5207bJohn Levon	return expr_to_var_sym(expr, NULL);
4871f5207bJohn Levon}
4881f5207bJohn Levon
4891f5207bJohn Levonstruct symbol *expr_to_sym(struct expression *expr)
4901f5207bJohn Levon{
4911f5207bJohn Levon	struct symbol *sym;
4921f5207bJohn Levon	char *name;
4931f5207bJohn Levon
4941f5207bJohn Levon	name = expr_to_var_sym(expr, &sym);
4951f5207bJohn Levon	free_string(name);
4961f5207bJohn Levon	return sym;
4971f5207bJohn Levon}
4981f5207bJohn Levon
4991f5207bJohn Levonint get_complication_score(struct expression *expr)
5001f5207bJohn Levon{
5011f5207bJohn Levon	expr = strip_expr(expr);
5021f5207bJohn Levon
5031f5207bJohn Levon	/*
5041f5207bJohn Levon	 * Don't forget to keep get_complication_score() and store_all_links()
5051f5207bJohn Levon	 * in sync.
5061f5207bJohn Levon	 *
5071f5207bJohn Levon	 */
5081f5207bJohn Levon
5091f5207bJohn Levon	if (!expr)
5101f5207bJohn Levon		return 990;
5111f5207bJohn Levon
5121f5207bJohn Levon	switch (expr->type) {
5131f5207bJohn Levon	case EXPR_CALL:
5141f5207bJohn Levon		return 991;
5151f5207bJohn Levon	case EXPR_COMPARE:
5161f5207bJohn Levon	case EXPR_BINOP:
5171f5207bJohn Levon		return get_complication_score(expr->left) +
5181f5207bJohn Levon		       get_complication_score(expr->right);
5191f5207bJohn Levon	case EXPR_SYMBOL:
5201f5207bJohn Levon		return 1;
5211f5207bJohn Levon	case EXPR_PREOP:
5221f5207bJohn Levon		if (expr->op == '*' || expr->op == '(')
5231f5207bJohn Levon			return get_complication_score(expr->unop);
5241f5207bJohn Levon		return 993;
5251f5207bJohn Levon	case EXPR_DEREF:
5261f5207bJohn Levon		return get_complication_score(expr->deref);
5271f5207bJohn Levon	case EXPR_VALUE:
5281f5207bJohn Levon	case EXPR_SIZEOF:
5291f5207bJohn Levon		return 0;
5301f5207bJohn Levon	default:
5311f5207bJohn Levon		return 994;
5321f5207bJohn Levon	}
5331f5207bJohn Levon}
5341f5207bJohn Levon
5351f5207bJohn Levonstruct expression *reorder_expr_alphabetically(struct expression *expr)
5361f5207bJohn Levon{
5371f5207bJohn Levon	struct expression *ret;
5381f5207bJohn Levon	char *left, *right;
5391f5207bJohn Levon
5401f5207bJohn Levon	if (expr->type != EXPR_BINOP)
5411f5207bJohn Levon		return expr;
5421f5207bJohn Levon	if (expr->op != '+' && expr->op != '*')
5431f5207bJohn Levon		return expr;
5441f5207bJohn Levon
5451f5207bJohn Levon	left = expr_to_var(expr->left);
5461f5207bJohn Levon	right = expr_to_var(expr->right);
5471f5207bJohn Levon	ret = expr;
5481f5207bJohn Levon	if (!left || !right)
5491f5207bJohn Levon		goto free;
5501f5207bJohn Levon	if (strcmp(left, right) <= 0)
5511f5207bJohn Levon		goto free;
5521f5207bJohn Levon
5531f5207bJohn Levon	ret = binop_expression(expr->right, expr->op, expr->left);
5541f5207bJohn Levonfree:
5551f5207bJohn Levon	free_string(left);
5561f5207bJohn Levon	free_string(right);
5571f5207bJohn Levon
5581f5207bJohn Levon	return ret;
5591f5207bJohn Levon}
5601f5207bJohn Levon
5611f5207bJohn Levonchar *expr_to_chunk_helper(struct expression *expr, struct symbol **sym, struct var_sym_list **vsl)
5621f5207bJohn Levon{
5631f5207bJohn Levon	struct var_sym_list *tmp_vsl;
5641f5207bJohn Levon	char *name;
5651f5207bJohn Levon	struct symbol *tmp;
5661f5207bJohn Levon	int score;
5671f5207bJohn Levon
5681f5207bJohn Levon	if (vsl)
5691f5207bJohn Levon		*vsl = NULL;
5701f5207bJohn Levon	if (sym)
5711f5207bJohn Levon		*sym = NULL;
5721f5207bJohn Levon
5731f5207bJohn Levon	expr = strip_parens(expr);
5741f5207bJohn Levon	if (!expr)
5751f5207bJohn Levon		return NULL;
5761f5207bJohn Levon
5771f5207bJohn Levon	name = expr_to_var_sym(expr, &tmp);
5781f5207bJohn Levon	if (name && tmp) {
5791f5207bJohn Levon		if (sym)
5801f5207bJohn Levon			*sym = tmp;
5811f5207bJohn Levon		if (vsl)
582efe51d0John Levon			add_var_sym(vsl, name, tmp);
5831f5207bJohn Levon		return name;
5841f5207bJohn Levon	}
5851f5207bJohn Levon	free_string(name);
5861f5207bJohn Levon
5871f5207bJohn Levon	score = get_complication_score(expr);
5881f5207bJohn Levon	if (score <= 0 || score > 2)
5891f5207bJohn Levon		return NULL;
5901f5207bJohn Levon
5911f5207bJohn Levon	tmp_vsl = expr_to_vsl(expr);
5921f5207bJohn Levon	if (vsl) {
5931f5207bJohn Levon		*vsl = tmp_vsl;
5941f5207bJohn Levon		if (!*vsl)
5951f5207bJohn Levon			return NULL;
5961f5207bJohn Levon	}
5971f5207bJohn Levon	if (sym) {
5981f5207bJohn Levon		if (ptr_list_size((struct ptr_list *)tmp_vsl) == 1) {
5991f5207bJohn Levon			struct var_sym *vs;
6001f5207bJohn Levon
6011f5207bJohn Levon			vs = first_ptr_list((struct ptr_list *)tmp_vsl);
6021f5207bJohn Levon			*sym = vs->sym;
6031f5207bJohn Levon		}
6041f5207bJohn Levon	}
6051f5207bJohn Levon
6061f5207bJohn Levon	expr = reorder_expr_alphabetically(expr);
6071f5207bJohn Levon
6081f5207bJohn Levon	return expr_to_str(expr);
6091f5207bJohn Levon}
6101f5207bJohn Levon
6111f5207bJohn Levonchar *expr_to_known_chunk_sym(struct expression *expr, struct symbol **sym)
6121f5207bJohn Levon{
6131f5207bJohn Levon	return expr_to_chunk_helper(expr, sym, NULL);
6141f5207bJohn Levon}
6151f5207bJohn Levon
6161f5207bJohn Levonchar *expr_to_chunk_sym_vsl(struct expression *expr, struct symbol **sym, struct var_sym_list **vsl)
6171f5207bJohn Levon{
6181f5207bJohn Levon	return expr_to_chunk_helper(expr, sym, vsl);
6191f5207bJohn Levon}
6201f5207bJohn Levon
6211f5207bJohn Levonint sym_name_is(const char *name, struct expression *expr)
6221f5207bJohn Levon{
6231f5207bJohn Levon	if (!expr)
6241f5207bJohn Levon		return 0;
6251f5207bJohn Levon	if (expr->type != EXPR_SYMBOL)
6261f5207bJohn Levon		return 0;
6271f5207bJohn Levon	if (!strcmp(expr->symbol_name->name, name))
6281f5207bJohn Levon		return 1;
6291f5207bJohn Levon	return 0;
6301f5207bJohn Levon}
6311f5207bJohn Levon
632c85f09cJohn Levonint expr_is_zero(struct expression *expr)
6331f5207bJohn Levon{
6341f5207bJohn Levon	sval_t sval;
6351f5207bJohn Levon
6361f5207bJohn Levon	if (get_value(expr, &sval) && sval.value == 0)
6371f5207bJohn Levon		return 1;
6381f5207bJohn Levon	return 0;
6391f5207bJohn Levon}
6401f5207bJohn Levon
6411f5207bJohn Levonint is_array(struct expression *expr)
6421f5207bJohn Levon{
6431f5207bJohn Levon	struct symbol *type;
6441f5207bJohn Levon
6451f5207bJohn Levon	expr = strip_expr(expr);
6461f5207bJohn Levon	if (!expr)
6471f5207bJohn Levon		return 0;
6481f5207bJohn Levon
6491f5207bJohn Levon	if (expr->type == EXPR_PREOP && expr->op == '*') {
6501f5207bJohn Levon		expr = strip_expr(expr->unop);
6511f5207bJohn Levon		if (!expr)
6521f5207bJohn Levon			return 0;
6531f5207bJohn Levon		if (expr->type == EXPR_BINOP && expr->op == '+')
6541f5207bJohn Levon			return 1;
6551f5207bJohn Levon	}
6561f5207bJohn Levon
6571f5207bJohn Levon	if (expr->type != EXPR_BINOP || expr->op != '+')
6581f5207bJohn Levon		return 0;
6591f5207bJohn Levon
6601f5207bJohn Levon	type = get_type(expr->left);
6611f5207bJohn Levon	if (!type || type->type != SYM_ARRAY)
6621f5207bJohn Levon		return 0;
6631f5207bJohn Levon
6641f5207bJohn Levon	return 1;
6651f5207bJohn Levon}
6661f5207bJohn Levon
6671f5207bJohn Levonstruct expression *get_array_base(struct expression *expr)
6681f5207bJohn Levon{
6691f5207bJohn Levon	if (!is_array(expr))
6701f5207bJohn Levon		return NULL;
6711f5207bJohn Levon	expr = strip_expr(expr);
6721f5207bJohn Levon	if (expr->type == EXPR_PREOP && expr->op == '*')
6731f5207bJohn Levon		expr = strip_expr(expr->unop);
6741f5207bJohn Levon	if (expr->type != EXPR_BINOP || expr->op != '+')
6751f5207bJohn Levon		return NULL;
6761f5207bJohn Levon	return strip_parens(expr->left);
6771f5207bJohn Levon}
6781f5207bJohn Levon
6791f5207bJohn Levonstruct expression *get_array_offset(struct expression *expr)
6801f5207bJohn Levon{
6811f5207bJohn Levon	if (!is_array(expr))
6821f5207bJohn Levon		return NULL;
6831f5207bJohn Levon	expr = strip_expr(expr);
6841f5207bJohn Levon	if (expr->type == EXPR_PREOP && expr->op == '*')
6851f5207bJohn Levon		expr = strip_expr(expr->unop);
6861f5207bJohn Levon	if (expr->type != EXPR_BINOP || expr->op != '+')
6871f5207bJohn Levon		return NULL;
6881f5207bJohn Levon	return strip_parens(expr->right);
6891f5207bJohn Levon}
6901f5207bJohn Levon
6911f5207bJohn Levonconst char *show_state(struct smatch_state *state)
6921f5207bJohn Levon{
6931f5207bJohn Levon	if (!state)
6941f5207bJohn Levon		return NULL;
6951f5207bJohn Levon	return state->name;
6961f5207bJohn Levon}
6971f5207bJohn Levon
6981f5207bJohn Levonstruct statement *get_expression_statement(struct expression *expr)
6991f5207bJohn Levon{
7001f5207bJohn Levon	/* What are those things called? if (({....; ret;})) { ...*/
7011f5207bJohn Levon
7021f5207bJohn Levon	if (expr->type != EXPR_PREOP)
7031f5207bJohn Levon		return NULL;
7041f5207bJohn Levon	if (expr->op != '(')
7051f5207bJohn Levon		return NULL;
7061f5207bJohn Levon	if (!expr->unop)
7071f5207bJohn Levon		return NULL;
7081f5207bJohn Levon	if (expr->unop->type != EXPR_STATEMENT)
7091f5207bJohn Levon		return NULL;
7101f5207bJohn Levon	if (expr->unop->statement->type != STMT_COMPOUND)
7111f5207bJohn Levon		return NULL;
7121f5207bJohn Levon	return expr->unop->statement;
7131f5207bJohn Levon}
7141f5207bJohn Levon
7151f5207bJohn Levonstruct expression *strip_parens(struct expression *expr)
7161f5207bJohn Levon{
7171f5207bJohn Levon	if (!expr)
7181f5207bJohn Levon		return NULL;
7191f5207bJohn Levon
7201f5207bJohn Levon	if (expr->type == EXPR_PREOP) {
7211f5207bJohn Levon		if (!expr->unop)
7221f5207bJohn Levon			return expr;  /* parsing invalid code */
7231f5207bJohn Levon
7241f5207bJohn Levon		if (expr->op == '(' && expr->unop->type == EXPR_STATEMENT &&
7251f5207bJohn Levon			expr->unop->statement->type == STMT_COMPOUND)
7261f5207bJohn Levon			return expr;
7271f5207bJohn Levon		if (expr->op == '(')
7281f5207bJohn Levon			return strip_parens(expr->unop);
7291f5207bJohn Levon	}
7301f5207bJohn Levon	return expr;
7311f5207bJohn Levon}
7321f5207bJohn Levon
7331f5207bJohn Levonstatic struct expression *strip_expr_helper(struct expression *expr, bool set_parent)
7341f5207bJohn Levon{
7351f5207bJohn Levon	if (!expr)
7361f5207bJohn Levon		return NULL;
7371f5207bJohn Levon
7381f5207bJohn Levon	switch (expr->type) {
7391f5207bJohn Levon	case EXPR_FORCE_CAST:
7401f5207bJohn Levon	case EXPR_CAST:
7411f5207bJohn Levon		if (set_parent)
7421f5207bJohn Levon			expr_set_parent_expr(expr->cast_expression, expr);
7431f5207bJohn Levon
7441f5207bJohn Levon		if (!expr->cast_expression)
7451f5207bJohn Levon			return expr;
7461f5207bJohn Levon		return strip_expr_helper(expr->cast_expression, set_parent);
7471f5207bJohn Levon	case EXPR_PREOP: {
7481f5207bJohn Levon		struct expression *unop;
7491f5207bJohn Levon
7501f5207bJohn Levon		if (!expr->unop)  /* parsing invalid code */
7511f5207bJohn Levon			return expr;
7521f5207bJohn Levon		if (set_parent)
7531f5207bJohn Levon			expr_set_parent_expr(expr->unop, expr);
7541f5207bJohn Levon
7551f5207bJohn Levon
7561f5207bJohn Levon		if (expr->op == '(' && expr->unop->type == EXPR_STATEMENT &&
7571f5207bJohn Levon			expr->unop->statement->type == STMT_COMPOUND)
7581f5207bJohn Levon			return expr;
7591f5207bJohn Levon
7601f5207bJohn Levon		unop = strip_expr_helper(expr->unop, set_parent);
7611f5207bJohn Levon
7621f5207bJohn Levon		if (expr->op == '*' && unop &&
7631f5207bJohn Levon		    unop->type == EXPR_PREOP && unop->op == '&') {
7641f5207bJohn Levon			struct symbol *type = get_type(unop->unop);
7651f5207bJohn Levon
7661f5207bJohn Levon			if (type && type->type == SYM_ARRAY)
7671f5207bJohn Levon				return expr;
7681f5207bJohn Levon			return strip_expr_helper(unop->unop, set_parent);
7691f5207bJohn Levon		}
7701f5207bJohn Levon
7711f5207bJohn Levon		if (expr->op == '(')
7721f5207bJohn Levon			return unop;
7731f5207bJohn Levon
7741f5207bJohn Levon		return expr;
7751f5207bJohn Levon	}
7761f5207bJohn Levon	case EXPR_CONDITIONAL:
7771f5207bJohn Levon		if (known_condition_true(expr->conditional)) {
7781f5207bJohn Levon			if (expr->cond_true) {
7791f5207bJohn Levon				if (set_parent)
7801f5207bJohn Levon					expr_set_parent_expr(expr->cond_true, expr);
7811f5207bJohn Levon				return strip_expr_helper(expr->cond_true, set_parent);
7821f5207bJohn Levon			}
7831f5207bJohn Levon			if (set_parent)
7841f5207bJohn Levon				expr_set_parent_expr(expr->conditional, expr);
7851f5207bJohn Levon			return strip_expr_helper(expr->conditional, set_parent);
7861f5207bJohn Levon		}
7871f5207bJohn Levon		if (known_condition_false(expr->conditional)) {
7881f5207bJohn Levon			if (set_parent)
7891f5207bJohn Levon				expr_set_parent_expr(expr->cond_false, expr);
7901f5207bJohn Levon			return strip_expr_helper(expr->cond_false, set_parent);
7911f5207bJohn Levon		}
7921f5207bJohn Levon		return expr;
7931f5207bJohn Levon	case EXPR_CALL:
7941f5207bJohn Levon		if (sym_name_is("__builtin_expect", expr->fn) ||
7951f5207bJohn Levon		    sym_name_is("__builtin_bswap16", expr->fn) ||
7961f5207bJohn Levon		    sym_name_is("__builtin_bswap32", expr->fn) ||
7971f5207bJohn Levon		    sym_name_is("__builtin_bswap64", expr->fn)) {
7981f5207bJohn Levon			expr = get_argument_from_call_expr(expr->args, 0);
7991f5207bJohn Levon			return strip_expr_helper(expr, set_parent);
8001f5207bJohn Levon		}
8011f5207bJohn Levon		return expr;
8021f5207bJohn Levon	}
8031f5207bJohn Levon	return expr;
8041f5207bJohn Levon}
8051f5207bJohn Levon
8061f5207bJohn Levonstruct expression *strip_expr(struct expression *expr)
8071f5207bJohn Levon{
8081f5207bJohn Levon	return strip_expr_helper(expr, false);
8091f5207bJohn Levon}
8101f5207bJohn Levon
8111f5207bJohn Levonstruct expression *strip_expr_set_parent(struct expression *expr)
8121f5207bJohn Levon{
8131f5207bJohn Levon	return strip_expr_helper(expr, true);
8141f5207bJohn Levon}
8151f5207bJohn Levon
8161f5207bJohn Levonstatic void delete_state_tracker(struct tracker *t)
8171f5207bJohn Levon{
8181f5207bJohn Levon	delete_state(t->owner, t->name, t->sym);
8191f5207bJohn Levon	__free_tracker(t);
8201f5207bJohn Levon}
8211f5207bJohn Levon
8221f5207bJohn Levonvoid scoped_state(int my_id, const char *name, struct symbol *sym)
8231f5207bJohn Levon{
8241f5207bJohn Levon	struct tracker *t;
8251f5207bJohn Levon
8261f5207bJohn Levon	t = alloc_tracker(my_id, name, sym);
8271f5207bJohn Levon	add_scope_hook((scope_hook *)&delete_state_tracker, t);
8281f5207bJohn Levon}
8291f5207bJohn Levon
8301f5207bJohn Levonint is_error_return(struct expression *expr)
8311f5207bJohn Levon{
8321f5207bJohn Levon	struct symbol *cur_func = cur_func_sym;
8331f5207bJohn Levon	struct range_list *rl;
8341f5207bJohn Levon	sval_t sval;
8351f5207bJohn Levon
8361f5207bJohn Levon	if (!expr)
8371f5207bJohn Levon		return 0;
8381f5207bJohn Levon	if (cur_func->type != SYM_NODE)
8391f5207bJohn Levon		return 0;
8401f5207bJohn Levon	cur_func = get_base_type(cur_func);
8411f5207bJohn Levon	if (cur_func->type != SYM_FN)
8421f5207bJohn Levon		return 0;
8431f5207bJohn Levon	cur_func = get_base_type(cur_func);
8441f5207bJohn Levon	if (cur_func == &void_ctype)
8451f5207bJohn Levon		return 0;
8461f5207bJohn Levon	if (option_project == PROJ_KERNEL &&
8471f5207bJohn Levon	    get_implied_rl(expr, &rl) &&
8481f5207bJohn Levon	    rl_type(rl) == &int_ctype &&
8491f5207bJohn Levon	    sval_is_negative(rl_min(rl)) &&
8501f5207bJohn Levon	    rl_max(rl).value == -1)
8511f5207bJohn Levon		return 1;
8521f5207bJohn Levon	if (!get_implied_value(expr, &sval))
8531f5207bJohn Levon		return 0;
8541f5207bJohn Levon	if (sval.value < 0)
8551f5207bJohn Levon		return 1;
8561f5207bJohn Levon	if (cur_func->type == SYM_PTR && sval.value == 0)
8571f5207bJohn Levon		return 1;
8581f5207bJohn Levon	return 0;
8591f5207bJohn Levon}
8601f5207bJohn Levon
861c85f09cJohn Levonint getting_address(struct expression *expr)
8621f5207bJohn Levon{
863c85f09cJohn Levon	int deref_count = 0;
8641f5207bJohn Levon
865c85f09cJohn Levon	while ((expr = expr_get_parent_expr(expr))) {
866c85f09cJohn Levon		if (expr->type == EXPR_PREOP && expr->op == '*') {
867c85f09cJohn Levon			/* &foo->bar->baz dereferences "foo->bar" */
868c85f09cJohn Levon			if (deref_count == 0)
869c85f09cJohn Levon				deref_count++;
870c85f09cJohn Levon			return false;
871c85f09cJohn Levon		}
872c85f09cJohn Levon		if (expr->type == EXPR_PREOP && expr->op == '&')
873c85f09cJohn Levon			return true;
874c85f09cJohn Levon	}
875c85f09cJohn Levon	return false;
8761f5207bJohn Levon}
8771f5207bJohn Levon
8781f5207bJohn Levonint get_struct_and_member(struct expression *expr, const char **type, const char **member)
8791f5207bJohn Levon{
8801f5207bJohn Levon	struct symbol *sym;
8811f5207bJohn Levon
8821f5207bJohn Levon	expr = strip_expr(expr);
8831f5207bJohn Levon	if (expr->type != EXPR_DEREF)
8841f5207bJohn Levon		return 0;
8851f5207bJohn Levon	if (!expr->member)
8861f5207bJohn Levon		return 0;
8871f5207bJohn Levon
8881f5207bJohn Levon	sym = get_type(expr->deref);
8891f5207bJohn Levon	if (!sym)
8901f5207bJohn Levon		return 0;
8911f5207bJohn Levon	if (sym->type == SYM_UNION)
8921f5207bJohn Levon		return 0;
8931f5207bJohn Levon	if (!sym->ident)
8941f5207bJohn Levon		return 0;
8951f5207bJohn Levon
8961f5207bJohn Levon	*type = sym->ident->name;
8971f5207bJohn Levon	*member = expr->member->name;
8981f5207bJohn Levon	return 1;
8991f5207bJohn Levon}
9001f5207bJohn Levon
9011f5207bJohn Levonchar *get_member_name(struct expression *expr)
9021f5207bJohn Levon{
9031f5207bJohn Levon	char buf[256];
9041f5207bJohn Levon	struct symbol *sym;
9051f5207bJohn Levon
9061f5207bJohn Levon	expr = strip_expr(expr);
9071f5207bJohn Levon	if (!expr || expr->type != EXPR_DEREF)
9081f5207bJohn Levon		return NULL;
9091f5207bJohn Levon	if (!expr->member)
9101f5207bJohn Levon		return NULL;
9111f5207bJohn Levon
9121f5207bJohn Levon	sym = get_type(expr->deref);
9131f5207bJohn Levon	if (!sym)
9141f5207bJohn Levon		return NULL;
9151f5207bJohn Levon	if (sym->type == SYM_UNION) {
9161f5207bJohn Levon		snprintf(buf, sizeof(buf), "(union %s)->%s",
9171f5207bJohn Levon			 sym->ident ? sym->ident->name : "anonymous",
9181f5207bJohn Levon			 expr->member->name);
9191f5207bJohn Levon		return alloc_string(buf);
9201f5207bJohn Levon	}
921efe51d0John Levon	if (!sym->ident) {
922efe51d0John Levon		struct expression *deref;
923efe51d0John Levon		char *full, *outer;
924efe51d0John Levon		int len;
925efe51d0John Levon
926efe51d0John Levon		/*
927efe51d0John Levon		 * If we're in an anonymous struct then maybe we can find an
928efe51d0John Levon		 * outer struct name to use as a name.  This code should be
929efe51d0John Levon		 * recursive and cleaner.  I am not very proud of it.
930efe51d0John Levon		 *
931efe51d0John Levon		 */
932efe51d0John Levon
933efe51d0John Levon		deref = expr->deref;
934efe51d0John Levon		if (deref->type != EXPR_DEREF || !deref->member)
935efe51d0John Levon			return NULL;
936efe51d0John Levon		sym = get_type(deref->deref);
937efe51d0John Levon		if (!sym || sym->type != SYM_STRUCT || !sym->ident)
938efe51d0John Levon			return NULL;
939efe51d0John Levon
940efe51d0John Levon		full = expr_to_str(expr);
941efe51d0John Levon		if (!full)
942efe51d0John Levon			return NULL;
943efe51d0John Levon		deref = deref->deref;
944efe51d0John Levon		if (deref->type == EXPR_PREOP && deref->op == '*')
945efe51d0John Levon			deref = deref->unop;
946efe51d0John Levon		outer = expr_to_str(deref);
947efe51d0John Levon		if (!outer) {
948efe51d0John Levon			free_string(full);
949efe51d0John Levon			return NULL;
950efe51d0John Levon		}
951efe51d0John Levon		len = strlen(outer);
952efe51d0John Levon		if (strncmp(outer, full, len) != 0) {
953efe51d0John Levon			free_string(full);
954efe51d0John Levon			free_string(outer);
955efe51d0John Levon			return NULL;
956efe51d0John Levon		}
957efe51d0John Levon		if (full[len] == '-' && full[len + 1] == '>')
958efe51d0John Levon			len += 2;
959efe51d0John Levon		if (full[len] == '.')
960efe51d0John Levon			len++;
961efe51d0John Levon		snprintf(buf, sizeof(buf), "(struct %s)->%s", sym->ident->name, full + len);
962efe51d0John Levon		free_string(outer);
963efe51d0John Levon		free_string(full);
964efe51d0John Levon
965efe51d0John Levon		return alloc_string(buf);
966efe51d0John Levon	}
9671f5207bJohn Levon	snprintf(buf, sizeof(buf), "(struct %s)->%s", sym->ident->name, expr->member->name);
9681f5207bJohn Levon	return alloc_string(buf);
9691f5207bJohn Levon}
9701f5207bJohn Levon
9711f5207bJohn Levonint cmp_pos(struct position pos1, struct position pos2)
9721f5207bJohn Levon{
9731f5207bJohn Levon	/* the stream position is ... */
9741f5207bJohn Levon	if (pos1.stream > pos2.stream)
9751f5207bJohn Levon		return -1;
9761f5207bJohn Levon	if (pos1.stream < pos2.stream)
9771f5207bJohn Levon		return 1;
9781f5207bJohn Levon
9791f5207bJohn Levon	if (pos1.line < pos2.line)
9801f5207bJohn Levon		return -1;
9811f5207bJohn Levon	if (pos1.line > pos2.line)
9821f5207bJohn Levon		return 1;
9831f5207bJohn Levon
9841f5207bJohn Levon	if (pos1.pos < pos2.pos)
9851f5207bJohn Levon		return -1;
9861f5207bJohn Levon	if (pos1.pos > pos2.pos)
9871f5207bJohn Levon		return 1;
9881f5207bJohn Levon
9891f5207bJohn Levon	return 0;
9901f5207bJohn Levon}
9911f5207bJohn Levon
9921f5207bJohn Levonint positions_eq(struct position pos1, struct position pos2)
9931f5207bJohn Levon{
9941f5207bJohn Levon	if (pos1.line != pos2.line)
9951f5207bJohn Levon		return 0;
9961f5207bJohn Levon	if (pos1.pos != pos2.pos)
9971f5207bJohn Levon		return 0;
9981f5207bJohn Levon	if (pos1.stream != pos2.stream)
9991f5207bJohn Levon		return 0;
10001f5207bJohn Levon	return 1;
10011f5207bJohn Levon}
10021f5207bJohn Levon
10031f5207bJohn Levonstruct statement *get_current_statement(void)
10041f5207bJohn Levon{
10051f5207bJohn Levon	struct statement *prev, *tmp;
10061f5207bJohn Levon
10071f5207bJohn Levon	prev = last_ptr_list((struct ptr_list *)big_statement_stack);
10081f5207bJohn Levon
10091f5207bJohn Levon	if (!prev || !get_macro_name(prev->pos))
10101f5207bJohn Levon		return prev;
10111f5207bJohn Levon
10121f5207bJohn Levon	FOR_EACH_PTR_REVERSE(big_statement_stack, tmp) {
10131f5207bJohn Levon		if (positions_eq(tmp->pos, prev->pos))
10141f5207bJohn Levon			continue;
10151f5207bJohn Levon		if (prev->pos.line > tmp->pos.line)
10161f5207bJohn Levon			return prev;
10171f5207bJohn Levon		return tmp;
10181f5207bJohn Levon	} END_FOR_EACH_PTR_REVERSE(tmp);
10191f5207bJohn Levon	return prev;
10201f5207bJohn Levon}
10211f5207bJohn Levon
10221f5207bJohn Levonstruct statement *get_prev_statement(void)
10231f5207bJohn Levon{
10241f5207bJohn Levon	struct statement *tmp;
10251f5207bJohn Levon	int i;
10261f5207bJohn Levon
10271f5207bJohn Levon	i = 0;
10281f5207bJohn Levon	FOR_EACH_PTR_REVERSE(big_statement_stack, tmp) {
10291f5207bJohn Levon		if (i++ == 1)
10301f5207bJohn Levon			return tmp;
10311f5207bJohn Levon	} END_FOR_EACH_PTR_REVERSE(tmp);
10321f5207bJohn Levon	return NULL;
10331f5207bJohn Levon}
10341f5207bJohn Levon
10351f5207bJohn Levonstruct expression *get_last_expr_from_expression_stmt(struct expression *expr)
10361f5207bJohn Levon{
10371f5207bJohn Levon	struct statement *stmt;
10381f5207bJohn Levon	struct statement *last_stmt;
10391f5207bJohn Levon
10401f5207bJohn Levon	while (expr->type == EXPR_PREOP && expr->op == '(')
10411f5207bJohn Levon		expr = expr->unop;
10421f5207bJohn Levon	if (expr->type != EXPR_STATEMENT)
10431f5207bJohn Levon		return NULL;
10441f5207bJohn Levon	stmt = expr->statement;
10451f5207bJohn Levon	if (!stmt)
10461f5207bJohn Levon		return NULL;
10471f5207bJohn Levon	if (stmt->type == STMT_COMPOUND) {
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