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AOT: fix mb_trim NestedJIT rtrim wrong output (leftover #34396) #34532

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Merged
PurHur merged 1 commit into from
Aug 24, 2026
Merged

AOT: fix mb_trim NestedJIT rtrim wrong output (leftover #34396) #34532

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73 changes: 47 additions & 26 deletions ext/mbstring/MbTrimJitHelper.php
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Original file line number Diff line number Diff line change
Expand Up @@ -11,6 +11,10 @@
* Private bodies: ascending for-loops only, no `break`/`continue`/strrev (those
* SIGSEGV under thin AOT when several leaves share a module).
*
* Byte access via $value[$i] — NestedJIT substr() mis-fires under thin AOT (#34338).
* Rtrim NBSP uses a C2-hold deferral — `$last = $i - 1` / `$last === $n - 1` miscompile
* under thin AOT (#34396 leftover).
*
* Default charset: ASCII ws + U+00A0 (C2 A0). php-src: ext/mbstring/mbstring.c
*/
final class MbTrimJitHelper
Expand Down Expand Up @@ -58,7 +62,7 @@ private static function trimLeftBody(string $value): string
$started = 0;
$prev = '';
for ($i = 0; $i < $n; ++$i) {
$c = \substr($value, $i, 1);
$c = $value[$i];
$ws = 0;
if (' ' === $c || "\t" === $c || "\n" === $c || "\r" === $c
|| "\0" === $c || "\x0B" === $c) {
Expand Down Expand Up @@ -100,33 +104,43 @@ private static function trimRightBody(string $value): string
{
$n = \strlen($value);
$last = -1;
$prev = '';
$pendingC2 = -1;
for ($i = 0; $i < $n; ++$i) {
$c = \substr($value, $i, 1);
$ws = 0;
if (' ' === $c || "\t" === $c || "\n" === $c || "\r" === $c
|| "\0" === $c || "\x0B" === $c) {
$ws = 1;
} elseif ("\xA0" === $c && "\xC2" === $prev) {
$ws = 1;
// previous C2 was start of NBSP — retract last if it pointed at C2
if ($last === $i - 1) {
$last = $i - 2;
$c = $value[$i];
if ($pendingC2 >= 0) {
if ("\xA0" === $c) {
$pendingC2 = -1;
} else {
$last = $pendingC2;
$pendingC2 = -1;
if (0 === self::defaultWsFlag($c)) {
$last = $i;
}
}
}
if (0 === $ws) {
} elseif ("\xC2" === $c) {
$pendingC2 = $i;
} elseif (0 === self::defaultWsFlag($c)) {
$last = $i;
}
$prev = $c;
}
if ($last === $n - 1) {
return $value;
if ($pendingC2 >= 0) {
$last = $pendingC2;
}
if ($last < 0) {
return '';
}

return \substr($value, 0, $last + 1);
return self::copyPrefix($value, $last + 1);
}

private static function defaultWsFlag(string $c): int
{
if (' ' === $c || "\t" === $c || "\n" === $c || "\r" === $c
|| "\0" === $c || "\x0B" === $c) {
return 1;
}

return 0;
}

private static function trimCharsLeftBody(string $value, string $what): string
Expand All @@ -136,11 +150,11 @@ private static function trimCharsLeftBody(string $value, string $what): string
$out = '';
$started = 0;
for ($i = 0; $i < $n; ++$i) {
$c = \substr($value, $i, 1);
$c = $value[$i];
if (0 === $started) {
$hit = 0;
for ($k = 0; $k < $wlen; ++$k) {
if (\substr($what, $k, 1) === $c) {
if ($what[$k] === $c) {
$hit = 1;
}
}
Expand All @@ -162,24 +176,31 @@ private static function trimCharsRightBody(string $value, string $what): string
$wlen = \strlen($what);
$last = -1;
for ($i = 0; $i < $n; ++$i) {
$c = \substr($value, $i, 1);
$c = $value[$i];
$hit = 0;
for ($k = 0; $k < $wlen; ++$k) {
if (\substr($what, $k, 1) === $c) {
if ($what[$k] === $c) {
$hit = 1;
}
}
if (0 === $hit) {
$last = $i;
}
}
if ($last === $n - 1) {
return $value;
}
if ($last < 0) {
return '';
}

return \substr($value, 0, $last + 1);
return self::copyPrefix($value, $last + 1);
}

private static function copyPrefix(string $value, int $len): string
{
$out = '';
for ($i = 0; $i < $len; ++$i) {
$out .= $value[$i];
}

return $out;
}
}
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