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php-in-php: hash_equals/hash_hmac_algos PHP LLVM (#7189 phase 1) #7480

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Merged
PurHur merged 1 commit into from
Jun 7, 2026
Merged

php-in-php: hash_equals/hash_hmac_algos PHP LLVM (#7189 phase 1) #7480

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7 changes: 5 additions & 2 deletions lib/JIT/Builtin/StringHashCryptoJit.php
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Expand Up @@ -11,7 +11,7 @@
* LLVM lowering for hash() / hash_hmac() / hash_pbkdf2() / hash_equals() / hash_hmac_algos().
*
* Compiles {@see hash_crypto_jit_runtime.c} to bitcode for MCJIT and AOT module link (#7060).
* Removed from {@see lib/AOT/Linker.php} — digest bodies live in the JIT link step, not AOT .o floor.
* hash_equals / hash_hmac_algos lowered in PHP LLVM via {@see StringHashEquals} / {@see StringHashHmacAlgos} (#7189 phase 1).
*/
final class StringHashCryptoJit
{
Expand All @@ -28,7 +28,10 @@ final class StringHashCryptoJit

public static function implement(Context $context): void
{
// AOT standalone resolves __compiler_hash* via Linker (hash_crypto_jit_runtime.c).
StringHashEquals::ensureLinked($context);
StringHashHmacAlgos::ensureLinked($context);

// AOT standalone: digest symbols still come from Linker (hash_crypto_jit_runtime.c).
if (Builtin::LOAD_TYPE_STANDALONE === $context->loadType) {
return;
}
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117 changes: 117 additions & 0 deletions lib/JIT/Builtin/StringHashEquals.php
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@@ -0,0 +1,117 @@
<?php

declare(strict_types=1);

namespace PHPCompiler\JIT\Builtin;

use PHPCompiler\JIT\Context;
use PHPLLVM\Builder;
use PHPLLVM\Value;
use PHPLLVM\Value\Function_ as LlvmFunction;

/**
* LLVM implementation of __compiler_hash_equals (issue #7189 phase 1).
*
* php-src: ext/hash/hash.c — timing-safe compare for hash_equals().
* VM semantics: ext/standard/VmHash::equals().
*/
final class StringHashEquals
{
public static function ensureLinked(Context $context): void
{
self::implement($context);
}

public static function implement(Context $context): void
{
$probe = $context->module->getNamedFunction('__compiler_hash_equals');
if (null !== $probe && $probe->countBasicBlocks() > 0) {
$context->registerFunction('__compiler_hash_equals', $probe);

return;
}

$strPtr = $context->getTypeFromString('__string__*');
$i32 = $context->getTypeFromString('int32');
$ft = $context->context->functionType($i32, false, $strPtr, $strPtr);
$fn = null !== $probe
? $probe
: $context->module->addFunction('__compiler_hash_equals', $ft);
self::implementHashEquals($context, $fn);
$context->registerFunction('__compiler_hash_equals', $fn);
}

private static function implementHashEquals(Context $context, LlvmFunction $fn): void
{
$entry = $fn->appendBasicBlock('hash_equals_entry');
$context->builder->positionAtEnd($entry);

$known = $fn->getParam(0);
$user = $fn->getParam(1);
$i32 = $context->getTypeFromString('int32');
$i64 = $context->getTypeFromString('int64');
$zeroI32 = $i32->constInt(0, false);
$oneI32 = $i32->constInt(1, false);
$zeroI64 = $i64->constInt(0, false);
$oneI64 = $i64->constInt(1, false);

$strlen = $context->lookupFunction('__string__strlen');
$knownLen = $context->builder->call($strlen, $known);
$userLen = $context->builder->call($strlen, $user);
$lenMismatch = $context->builder->icmp(Builder::INT_NE, $knownLen, $userLen);

$failBb = $fn->appendBasicBlock('hash_equals_fail');
$loopHead = $fn->appendBasicBlock('hash_equals_loop_head');
$context->builder->branchIf($lenMismatch, $failBb, $loopHead);

$context->builder->positionAtEnd($failBb);
$context->builder->returnValue($zeroI32);
$context->builder->clearInsertionPosition();

$knownData = self::stringData($context, $known);
$userData = self::stringData($context, $user);
$iSlot = $context->builder->alloca($i64, 1, 'hash_equals_i');
$accSlot = $context->builder->alloca($i32, 1, 'hash_equals_acc');
$context->builder->store($zeroI64, $iSlot);
$context->builder->store($zeroI32, $accSlot);

$context->builder->positionAtEnd($loopHead);
$i = $context->builder->load($iSlot);
$done = $context->builder->icmp(Builder::INT_SGE, $i, $knownLen);
$loopBody = $fn->appendBasicBlock('hash_equals_loop_body');
$loopDone = $fn->appendBasicBlock('hash_equals_loop_done');
$context->builder->branchIf($done, $loopDone, $loopBody);

$context->builder->positionAtEnd($loopBody);
$ka = $context->builder->load($context->builder->gep($knownData, $i));
$ua = $context->builder->load($context->builder->gep($userData, $i));
$xor = $context->builder->xor(
$context->builder->zExt($ka, $i32),
$context->builder->zExt($ua, $i32)
);
$acc = $context->builder->load($accSlot);
$context->builder->store($context->builder->or($acc, $xor), $accSlot);
$context->builder->store($context->builder->addNoSignedWrap($i, $oneI64), $iSlot);
$context->builder->branch($loopHead);

$context->builder->positionAtEnd($loopDone);
$finalAcc = $context->builder->load($accSlot);
$isZero = $context->builder->icmp(Builder::INT_EQ, $finalAcc, $zeroI32);
$okBb = $fn->appendBasicBlock('hash_equals_ok');
$context->builder->branchIf($isZero, $okBb, $failBb);

$context->builder->positionAtEnd($okBb);
$context->builder->returnValue($oneI32);
$context->builder->clearInsertionPosition();
}

private static function stringData(Context $context, Value $str): Value
{
$map = $context->structFieldMap['__string__'];

return $context->builder->pointerCast(
$context->builder->structGep($str, $map['value']),
$context->getTypeFromString('int8*')
);
}
}
90 changes: 90 additions & 0 deletions lib/JIT/Builtin/StringHashHmacAlgos.php
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@@ -0,0 +1,90 @@
<?php

declare(strict_types=1);

namespace PHPCompiler\JIT\Builtin;

use PHPCompiler\JIT\Context;
use PHPLLVM\Builder;
use PHPLLVM\Value\Function_ as LlvmFunction;

/**
* LLVM implementation of __compiler_hash_hmac_algos (issue #7189 phase 1).
*
* php-src: ext/hash/hash.c — HMAC-capable digest names.
* VM semantics: ext/standard/VmHash::hmacAlgos().
*/
final class StringHashHmacAlgos
{
/** @var list<string> */
private const HMAC_ALGOS = ['md5', 'sha1', 'sha256'];

public static function ensureLinked(Context $context): void
{
self::implement($context);
}

public static function implement(Context $context): void
{
$probe = $context->module->getNamedFunction('__compiler_hash_hmac_algos');
if (null !== $probe && $probe->countBasicBlocks() > 0) {
$context->registerFunction('__compiler_hash_hmac_algos', $probe);

return;
}

$htPtr = $context->getTypeFromString('__hashtable__*');
$ft = $context->context->functionType($htPtr, false);
$fn = null !== $probe
? $probe
: $context->module->addFunction('__compiler_hash_hmac_algos', $ft);
self::implementHashHmacAlgos($context, $fn);
$context->registerFunction('__compiler_hash_hmac_algos', $fn);
}

private static function implementHashHmacAlgos(Context $context, LlvmFunction $fn): void
{
$entry = $fn->appendBasicBlock('hash_hmac_algos_entry');
$context->builder->positionAtEnd($entry);

$htPtr = $context->getTypeFromString('__hashtable__*');
$i64 = $context->getTypeFromString('int64');
$ht = $context->builder->call($context->lookupFunction('__hashtable__alloc'));
$nullHt = $htPtr->constNull();
$isNull = $context->builder->icmp(Builder::INT_EQ, $ht, $nullHt);

$failBb = $fn->appendBasicBlock('hash_hmac_algos_fail');
$buildBb = $fn->appendBasicBlock('hash_hmac_algos_build');
$context->builder->branchIf($isNull, $failBb, $buildBb);

$context->builder->positionAtEnd($failBb);
$context->builder->returnValue($nullHt);
$context->builder->clearInsertionPosition();

$context->builder->positionAtEnd($buildBb);
$setAt = $context->lookupFunction('__hashtable__setStringAt');
foreach (self::HMAC_ALGOS as $index => $algo) {
$context->builder->call(
$setAt,
$ht,
$i64->constInt($index, false),
self::literalString($context, $algo)
);
}
$context->builder->returnValue($ht);
$context->builder->clearInsertionPosition();
}

private static function literalString(Context $context, string $text): \PHPLLVM\Value
{
$i64 = $context->getTypeFromString('int64');
$charPtr = $context->getTypeFromString('char*');
$cstr = $context->builder->pointerCast($context->constantFromString($text), $charPtr);

return $context->builder->call(
$context->lookupFunction('__string__init'),
$i64->constInt(\strlen($text), false),
$cstr
);
}
}
38 changes: 0 additions & 38 deletions lib/JIT/Builtin/hash_crypto_jit_runtime.c
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Expand Up @@ -760,41 +760,3 @@ __string__ *__compiler_hash_pbkdf2(
return result;
}

/** Timing-safe string compare for hash_equals() (issue #2179). */
int __compiler_hash_equals(__string__ *known, __string__ *user)
{
size_t known_len = hc_strlen(known);
size_t user_len = hc_strlen(user);
const unsigned char *ka = (const unsigned char *) hc_strdata(known);
const unsigned char *ua = (const unsigned char *) hc_strdata(user);
size_t len = known_len;
int result = 0;

if (known_len != user_len) {
return 0;
}
for (size_t i = 0; i < len; i++) {
result |= ka[i] ^ ua[i];
}

return result == 0 ? 1 : 0;
}

/** hash_hmac_algos() — HMAC-capable digest names (ext/hash/hash.c, issue #6229). */
__hashtable__ *__compiler_hash_hmac_algos(void)
{
static const char *algos[] = {"md5", "sha1", "sha256", NULL};
__hashtable__ *ht;
size_t i;

ht = __hashtable__alloc();
if (NULL == ht) {
return NULL;
}
for (i = 0; algos[i] != NULL; ++i) {
size_t len = strlen(algos[i]);
__hashtable__setStringAt(ht, i, __string__init((long long) len, algos[i]));
}

return ht;
}
7 changes: 7 additions & 0 deletions test/unit/JIT/StringHashCryptoRuntimeStandaloneTest.php
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Expand Up @@ -19,10 +19,17 @@ public function testRuntimeShrinkRemovesHashCryptoC(): void
$this->assertFileExists(__DIR__.'/../../../lib/JIT/Builtin/hash_crypto_jit_runtime.c');
$jit = (string) file_get_contents(__DIR__.'/../../../lib/JIT/Builtin/StringHashCryptoJit.php');
$this->assertStringContainsString('__compiler_hash', $jit);
$this->assertStringContainsString('StringHashEquals', $jit);
$this->assertStringContainsString('StringHashHmacAlgos', $jit);
$this->assertStringContainsString('StringHashCryptoJit', $jit);
$linker = (string) file_get_contents(__DIR__.'/../../../lib/AOT/Linker.php');
$this->assertStringNotContainsString('runtime/hash_crypto.c', $linker);
$this->assertStringContainsString('hash_crypto_jit_runtime.c', $linker);
$runtimeC = (string) file_get_contents(__DIR__.'/../../../lib/JIT/Builtin/hash_crypto_jit_runtime.c');
$this->assertStringNotContainsString('__compiler_hash_equals', $runtimeC);
$this->assertStringNotContainsString('__compiler_hash_hmac_algos', $runtimeC);
$equalsJit = (string) file_get_contents(__DIR__.'/../../../lib/JIT/Builtin/StringHashEquals.php');
$this->assertStringContainsString('__compiler_hash_equals', $equalsJit);
$runtime = (string) file_get_contents(__DIR__.'/../../../lib/JIT/Builtin/StringHashCrypto.php');
$this->assertStringContainsString('StringHashCryptoJit', $runtime);
$this->assertStringNotContainsString('hash_crypto.c', $runtime);
Expand Down