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lint: merge duplicate code for checking array index

This commit is contained in:
rillig 2024-03-09 14:54:14 +00:00
parent 6e7bb15f48
commit 4ed4a1b76a
1 changed files with 25 additions and 50 deletions
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75
usr.bin/xlint/lint1/tree.c
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@ -1,4 +1,4 @@
/* $NetBSD: tree.c,v 1.612 2024/03/09 13:54:47 rillig Exp $ */
/* $NetBSD: tree.c,v 1.613 2024/03/09 14:54:14 rillig Exp $ */
/*
* Copyright (c) 1994, 1995 Jochen Pohl
@ -37,7 +37,7 @@
#include <sys/cdefs.h>
#if defined(__RCSID)
__RCSID("$NetBSD: tree.c,v 1.612 2024/03/09 13:54:47 rillig Exp $");
__RCSID("$NetBSD: tree.c,v 1.613 2024/03/09 14:54:14 rillig Exp $");
#endif
#include <float.h>
@ -4327,52 +4327,37 @@ expr(tnode_t *tn, bool vctx, bool cond, bool dofreeblk, bool is_do_while)
expr_free_all();
}
/*
* Checks the range of array indices, if possible.
* amper is set if only the address of the element is used. This
* means that the index is allowed to refer to the first element
* after the array.
*/
/* If the expression has the form '*(arr + idx)', check the array index. */
static void
check_array_index(tnode_t *tn, bool amper)
check_array_index(const tnode_t *indir, bool taking_address)
{
lint_assert(has_operands(tn));
const tnode_t *ln = tn->u.ops.left;
const tnode_t *rn = tn->u.ops.right;
const tnode_t *plus, *arr, *idx;
/* We can only check constant indices. */
if (rn->tn_op != CON)
return;
if (indir->tn_op == INDIR
&& (plus = indir->u.ops.left, plus->tn_op == PLUS)
&& plus->u.ops.left->tn_op == ADDR
&& (arr = plus->u.ops.left->u.ops.left, true)
&& (arr->tn_op == STRING || arr->tn_op == NAME)
&& arr->tn_type->t_tspec == ARRAY
&& (idx = plus->u.ops.right, idx->tn_op == CON)
&& (!is_incomplete(arr->tn_type) || idx->u.value.u.integer < 0))
goto proceed;
return;
/* Return if the left node does not stem from an array. */
if (ln->tn_op != ADDR)
return;
if (ln->u.ops.left->tn_op != STRING && ln->u.ops.left->tn_op != NAME)
return;
if (ln->u.ops.left->tn_type->t_tspec != ARRAY)
return;
/*
* For incomplete array types, we can print a warning only if the index
* is negative.
*/
if (is_incomplete(ln->u.ops.left->tn_type)
&& rn->u.value.u.integer >= 0)
return;
int elsz = length_in_bits(ln->tn_type->t_subt, NULL);
proceed:;
int elsz = length_in_bits(arr->tn_type->t_subt, NULL);
if (elsz == 0)
return;
elsz /= CHAR_SIZE;
/* Change the unit of the index from bytes to element size. */
int64_t con = is_uinteger(rn->tn_type->t_tspec)
? (int64_t)((uint64_t)rn->u.value.u.integer / elsz)
: rn->u.value.u.integer / elsz;
int64_t con = is_uinteger(idx->tn_type->t_tspec)
? (int64_t)((uint64_t)idx->u.value.u.integer / elsz)
: idx->u.value.u.integer / elsz;
int dim = ln->u.ops.left->tn_type->u.dimension + (amper ? 1 : 0);
int dim = arr->tn_type->u.dimension + (taking_address ? 1 : 0);
if (!is_uinteger(rn->tn_type->t_tspec) && con < 0)
if (!is_uinteger(idx->tn_type->t_tspec) && con < 0)
/* array subscript cannot be negative: %ld */
warning(167, (long)con);
else if (dim > 0 && (uint64_t)con >= (uint64_t)dim)
@ -4389,15 +4374,7 @@ check_expr_addr(const tnode_t *ln, bool szof, bool fcall)
mark_as_set(ln->u.sym);
mark_as_used(ln->u.sym, fcall, szof);
}
if (ln->tn_op == INDIR && ln->u.ops.left->tn_op == PLUS)
check_array_index(ln->u.ops.left, true);
}
static void
check_expr_load(const tnode_t *ln)
{
if (ln->tn_op == INDIR && ln->u.ops.left->tn_op == PLUS)
check_array_index(ln->u.ops.left, false);
check_array_index(ln, true);
}
/*
@ -4439,9 +4416,7 @@ check_expr_assign(const tnode_t *ln, bool szof)
if (ln->u.sym->s_scl == EXTERN)
outusg(ln->u.sym);
}
if (ln->tn_op == INDIR && ln->u.ops.left->tn_op == PLUS)
/* check the range of array indices */
check_array_index(ln->u.ops.left, false);
check_array_index(ln, false);
}
static void
@ -4463,7 +4438,7 @@ check_expr_op(op_t op, const tnode_t *ln, bool szof, bool fcall, bool eqwarn)
check_expr_addr(ln, szof, fcall);
break;
case LOAD:
check_expr_load(ln);
check_array_index(ln, false);
/* FALLTHROUGH */
case INCBEF:
case DECBEF: