From 8305a73483e854f314b8afa2d65dbcb0e7fae1b9 Mon Sep 17 00:00:00 2001
From: Dmitry Stogov <dmitry@zend.com>
Date: Mon, 4 Dec 2017 23:40:54 +0300
Subject: [PATCH] Implemented x86 and x86_64 assembler functions for
 zend_string equality check. They take into account zend_string layout (value
 alignment and trailing padding) and perform comparison by double or quad
 words.

---
 Zend/zend_string.c | 72 ++++++++++++++++++++++++++++++++++++++++++++++
 Zend/zend_string.h | 11 ++++++-
 2 files changed, 82 insertions(+), 1 deletion(-)

diff --git a/Zend/zend_string.c b/Zend/zend_string.c
index bceb328f7f..5c280ce0f4 100644
--- a/Zend/zend_string.c
+++ b/Zend/zend_string.c
@@ -309,6 +309,78 @@ ZEND_API void zend_interned_strings_switch_storage(zend_bool request)
 	}
 }
 
+#if defined(__GNUC__) && defined(__i386__)
+ZEND_API zend_bool ZEND_FASTCALL zend_string_equal_val(zend_string *s1, zend_string *s2)
+{
+	zend_ulong ret;
+
+	__asm__ (
+		"subl %1, %2\n\t"
+		"ll0%=:\n\t"
+		"movl (%1,%2), %0\n\t"
+		"xorl (%1), %0\n\t"
+		"jne ll1%=\n\t"
+		"addl $0x4, %1\n\t"
+		"subl $0x4, %3\n\t"
+		"jg ll0%=\n\t"
+		"movl $0x1, %0\n\t"
+		"jmp ll3%=\n\t"
+		"ll1%=:\n\t"
+		"cmpl $0x4,%3\n\t"
+		"jl ll2%=\n\t"
+		"xorl %0, %0\n\t"
+		"jmp ll3%=\n\t"
+		"ll2%=:\n\t"
+		"negl %3\n\t"
+		"lea 0x1c(,%3,8), %3\n\t"
+		"shll %b3, %0\n\t"
+		"sete %b0\n\t"
+		"andl $0x1, %0\n\t"
+		"ll3%=:\n"
+		: "=&a"(ret)
+		: "d"(ZSTR_VAL(s2)),
+		  "r"(ZSTR_VAL(s1)),
+		  "c"(ZSTR_LEN(s1))
+		: "cc");
+	return ret;
+}
+#elif defined(__GNUC__) && defined(__x86_64__)
+ZEND_API zend_bool ZEND_FASTCALL zend_string_equal_val(zend_string *s1, zend_string *s2)
+{
+	zend_ulong ret;
+
+	__asm__ (
+		"subq %1, %2\n\t"
+		"ll0%=:\n\t"
+		"movq (%1,%2), %0\n\t"
+		"xorq (%1), %0\n\t"
+		"jne ll1%=\n\t"
+		"addq $0x8, %1\n\t"
+		"subq $0x8, %3\n\t"
+		"jg ll0%=\n\t"
+		"movq $0x1, %0\n\t"
+		"jmp ll3%=\n\t"
+		"ll1%=:\n\t"
+		"cmpq $0x8,%3\n\t"
+		"jl ll2%=\n\t"
+		"xorq %0, %0\n\t"
+		"jmp ll3%=\n\t"
+		"ll2%=:\n\t"
+		"negq %3\n\t"
+		"lea 0x3c(,%3,8), %3\n\t"
+		"shlq %b3, %0\n\t"
+		"sete %b0\n\t"
+		"andq $0x1, %0\n\t"
+		"ll3%=:\n"
+		: "=&a"(ret)
+		: "r"(ZSTR_VAL(s2)),
+		  "r"(ZSTR_VAL(s1)),
+		  "c"(ZSTR_LEN(s1))
+		: "cc");
+	return ret;
+}
+#endif
+
 /*
  * Local variables:
  * tab-width: 4
diff --git a/Zend/zend_string.h b/Zend/zend_string.h
index 686895d817..2bbcdb80a8 100644
--- a/Zend/zend_string.h
+++ b/Zend/zend_string.h
@@ -288,9 +288,18 @@ static zend_always_inline void zend_string_release(zend_string *s)
 	}
 }
 
+#if defined(__GNUC__) && (defined(__i386__) || defined(__x86_64__))
+ZEND_API zend_bool ZEND_FASTCALL zend_string_equal_val(zend_string *s1, zend_string *s2);
+#else
+static zend_always_inline zend_bool zend_string_equal_val(zend_string *s1, zend_string *s2)
+{
+	return !memcmp(ZSTR_VAL(s1), ZSTR_VAL(s2), ZSTR_LEN(s1));
+}
+#endif
+
 static zend_always_inline zend_bool zend_string_equal_content(zend_string *s1, zend_string *s2)
 {
-	return ZSTR_LEN(s1) == ZSTR_LEN(s2) && !memcmp(ZSTR_VAL(s1), ZSTR_VAL(s2), ZSTR_LEN(s1));
+	return ZSTR_LEN(s1) == ZSTR_LEN(s2) && zend_string_equal_val(s1, s2);
 }
 
 static zend_always_inline zend_bool zend_string_equals(zend_string *s1, zend_string *s2)
-- 
2.50.1