Module Name: src
Committed By: rillig
Date: Wed Jan 1 14:09:28 UTC 2025
Modified Files:
src/tests/usr.bin/xlint/lint1: msg_132.c
src/usr.bin/xlint/lint1: tree.c
Log Message:
lint: fix wrong warning about possible loss of accuracy
The expression "'0' + random() % 10" always fits in a signed or unsigned
char.
To generate a diff of this commit:
cvs rdiff -u -r1.47 -r1.48 src/tests/usr.bin/xlint/lint1/msg_132.c
cvs rdiff -u -r1.664 -r1.665 src/usr.bin/xlint/lint1/tree.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/tests/usr.bin/xlint/lint1/msg_132.c
diff -u src/tests/usr.bin/xlint/lint1/msg_132.c:1.47 src/tests/usr.bin/xlint/lint1/msg_132.c:1.48
--- src/tests/usr.bin/xlint/lint1/msg_132.c:1.47 Wed Jan 1 14:03:42 2025
+++ src/tests/usr.bin/xlint/lint1/msg_132.c Wed Jan 1 14:09:28 2025
@@ -1,4 +1,4 @@
-/* $NetBSD: msg_132.c,v 1.47 2025/01/01 14:03:42 rillig Exp $ */
+/* $NetBSD: msg_132.c,v 1.48 2025/01/01 14:09:28 rillig Exp $ */
# 3 "msg_132.c"
// Test for message: conversion from '%s' to '%s' may lose accuracy [132]
@@ -307,9 +307,7 @@ test_ic_plus(void)
{
/* expect+1: warning: conversion from 'long long' to 'signed char' may lose accuracy [132] */
s8 = -129 + s64 % 1;
- /* expect+1: warning: conversion from 'long long' to 'signed char' may lose accuracy [132] */
s8 = -128 + s64 % 1;
- /* expect+1: warning: conversion from 'long long' to 'signed char' may lose accuracy [132] */
s8 = 127 + s64 % 1;
/* expect+1: warning: conversion from 'long long' to 'signed char' may lose accuracy [132] */
s8 = 128 + s64 % 1;
@@ -320,19 +318,15 @@ test_ic_plus(void)
/* expect+2: warning: conversion of negative constant -128 to unsigned type 'unsigned long long' [222] */
/* expect+1: warning: conversion from 'unsigned long long' to 'signed char' may lose accuracy [132] */
s8 = -128 + u64 % 1;
- /* expect+1: warning: conversion from 'unsigned long long' to 'signed char' may lose accuracy [132] */
s8 = 127 + u64 % 1;
/* expect+1: warning: conversion from 'unsigned long long' to 'signed char' may lose accuracy [132] */
s8 = 128 + u64 % 1;
- /* expect+1: warning: conversion from 'unsigned long long' to 'unsigned char' may lose accuracy [132] */
u8 = 0 + u64 % 1;
- /* expect+1: warning: conversion from 'unsigned long long' to 'unsigned char' may lose accuracy [132] */
u8 = 255 + u64 % 1;
/* expect+1: warning: conversion from 'unsigned long long' to 'unsigned char' may lose accuracy [132] */
u8 = 256 + u64 % 1;
- /* expect+1: warning: conversion from 'long long' to 'signed char' may lose accuracy [132] */
s8 = '0' + s64 % 10;
}
Index: src/usr.bin/xlint/lint1/tree.c
diff -u src/usr.bin/xlint/lint1/tree.c:1.664 src/usr.bin/xlint/lint1/tree.c:1.665
--- src/usr.bin/xlint/lint1/tree.c:1.664 Sun Dec 15 06:04:17 2024
+++ src/usr.bin/xlint/lint1/tree.c Wed Jan 1 14:09:28 2025
@@ -1,4 +1,4 @@
-/* $NetBSD: tree.c,v 1.664 2024/12/15 06:04:17 rillig Exp $ */
+/* $NetBSD: tree.c,v 1.665 2025/01/01 14:09:28 rillig Exp $ */
/*
* Copyright (c) 1994, 1995 Jochen Pohl
@@ -37,7 +37,7 @@
#include <sys/cdefs.h>
#if defined(__RCSID)
-__RCSID("$NetBSD: tree.c,v 1.664 2024/12/15 06:04:17 rillig Exp $");
+__RCSID("$NetBSD: tree.c,v 1.665 2025/01/01 14:09:28 rillig Exp $");
#endif
#include <float.h>
@@ -83,6 +83,45 @@ u64_max(uint64_t a, uint64_t b)
return a > b ? a : b;
}
+static int64_t
+si_min_value(const type_t *tp)
+{
+ uint64_t mask = value_bits(size_in_bits(tp->t_tspec));
+ return -(int64_t)(mask >> 1) - 1;
+}
+
+static int64_t
+si_max_value(const type_t *tp)
+{
+ uint64_t mask = value_bits(size_in_bits(tp->t_tspec));
+ return (int64_t)(mask >> 1);
+}
+
+static uint64_t
+ui_max_value(const type_t *tp)
+{
+ return value_bits(size_in_bits(tp->t_tspec));
+}
+
+static int64_t
+si_plus_sat(const type_t *tp, int64_t a, int64_t b)
+{
+ if (a >= 0) {
+ int64_t max = si_max_value(tp);
+ return b <= max - a ? a + b : max;
+ } else {
+ int64_t min = si_min_value(tp);
+ return b >= min - a ? a + b : min;
+ }
+}
+
+static uint64_t
+ui_plus_sat(const type_t *tp, uint64_t a, uint64_t b)
+{
+ uint64_t max = ui_max_value(tp);
+ return b <= max - a ? a + b : max;
+}
+
static uint64_t
u64_fill_right(uint64_t x)
{
@@ -219,6 +258,20 @@ ic_mod(const type_t *tp, integer_constra
}
static integer_constraints
+ic_plus(const type_t *tp, integer_constraints a, integer_constraints b)
+{
+ bool maybe_signed = ic_maybe_signed(tp, &a) || ic_maybe_signed(tp, &b);
+
+ integer_constraints c;
+ c.smin = maybe_signed ? si_plus_sat(tp, a.smin, b.smin) : INT64_MIN;
+ c.smax = maybe_signed ? si_plus_sat(tp, a.smax, b.smax) : INT64_MAX;
+ c.umin = maybe_signed ? 0 : ui_plus_sat(tp, a.umin, b.umin);
+ c.umax = maybe_signed ? UINT64_MAX : ui_plus_sat(tp, a.umax, b.umax);
+ c.bclr = ~u64_fill_right(c.umax);
+ return c;
+}
+
+static integer_constraints
ic_shl(const type_t *tp, integer_constraints a, integer_constraints b)
{
integer_constraints c;
@@ -360,6 +413,10 @@ ic_expr(const tnode_t *tn)
lc = ic_expr(before_conversion(tn->u.ops.left));
rc = ic_expr(before_conversion(tn->u.ops.right));
return ic_mod(tn->tn_type, lc, rc);
+ case PLUS:
+ lc = ic_expr(before_conversion(tn->u.ops.left));
+ rc = ic_expr(before_conversion(tn->u.ops.right));
+ return ic_plus(tn->tn_type, lc, rc);
case SHL:
lc = ic_expr(tn->u.ops.left);
rc = ic_expr(tn->u.ops.right);
