Changeset 280984 in webkit

Timestamp:

Aug 12, 2021, 1:45:02 PM (5 years ago)

Author:

sbarati@apple.com

Message:

Update ARM64EHash
​https://bugs.webkit.org/show_bug.cgi?id=228962
<rdar://79883337>

Reviewed by Mark Lam.

• assembler/AssemblerBuffer.h:

(JSC::ARM64EHash::makeDiversifier):
(JSC::ARM64EHash::nextValue):
(JSC::ARM64EHash::bitsForDiversifier):
(JSC::ARM64EHash::currentHash):
(JSC::ARM64EHash::setUpdatedHash):
(JSC::ARM64EHash::ARM64EHash):
(JSC::ARM64EHash::update):
(JSC::ARM64EHash::finalize):
(JSC::AssemblerBuffer::AssemblerBuffer):
(JSC::AssemblerBuffer::putIntegralUnchecked):
(JSC::AssemblerBuffer::hash const):

• assembler/LinkBuffer.cpp:

(JSC::LinkBuffer::copyCompactAndLinkCode):

Location:

trunk/Source/JavaScriptCore

Files:

• ChangeLog (modified) (1 diff)
• assembler/AssemblerBuffer.h (modified) (3 diffs)
• assembler/LinkBuffer.cpp (modified) (2 diffs)

trunk/Source/JavaScriptCore/ChangeLog

@@ +1 @@
+2021-08-12  Saam Barati  <sbarati@apple.com>
+
+        Update ARM64EHash
+        https://bugs.webkit.org/show_bug.cgi?id=228962
+        <rdar://79883337>
+
+        Reviewed by Mark Lam.
+
+        * assembler/AssemblerBuffer.h:
+        (JSC::ARM64EHash::makeDiversifier):
+        (JSC::ARM64EHash::nextValue):
+        (JSC::ARM64EHash::bitsForDiversifier):
+        (JSC::ARM64EHash::currentHash):
+        (JSC::ARM64EHash::setUpdatedHash):
+        (JSC::ARM64EHash::ARM64EHash):
+        (JSC::ARM64EHash::update):
+        (JSC::ARM64EHash::finalize):
+        (JSC::AssemblerBuffer::AssemblerBuffer):
+        (JSC::AssemblerBuffer::putIntegralUnchecked):
+        (JSC::AssemblerBuffer::hash const):
+        * assembler/LinkBuffer.cpp:
+        (JSC::LinkBuffer::copyCompactAndLinkCode):
+
 2021-08-11  Yusuke Suzuki  <ysuzuki@apple.com>
 

trunk/Source/JavaScriptCore/assembler/AssemblerBuffer.h

@@ -206 +206 @@
     class ARM64EHash {
     public:
-        ARM64EHash(uint32_t initialHash)
-            : m_hash(initialHash)
-        {
-        }
-
-        ALWAYS_INLINE uint32_t update(uint32_t value)
-        {
-            uint64_t input = value ^ m_hash;
-            uint64_t a = static_cast<uint32_t>(tagInt(input, static_cast<PtrTag>(0)) >> 39);
-            uint64_t b = tagInt(input, static_cast<PtrTag>(0xb7e151628aed2a6a)) >> 23;
-            m_hash = a ^ b;
-            return m_hash;
+        static constexpr uint8_t initializationNamespace = 0x11;
+
+        static ALWAYS_INLINE PtrTag makeDiversifier(uint8_t namespaceTag, uint64_t index, uint32_t value)
+        {
+            // <namespaceTag:8><index:24><value:32>
+            return static_cast<PtrTag>((static_cast<uint64_t>(namespaceTag) << 56) + ((index & 0xFFFFFF) << 32) + static_cast<uint64_t>(value));
+        }
+
+        static ALWAYS_INLINE uint32_t nextValue(uint64_t instruction, uint64_t index, uint32_t currentValue)
+        {
+            uint64_t a = tagInt(instruction, makeDiversifier(0x12, index, currentValue));
+            uint64_t b = tagInt(instruction, makeDiversifier(0x13, index, currentValue));
+            return static_cast<uint32_t>((a >> 39) ^ (b >> 23));
+        }
+
+        static ALWAYS_INLINE uint32_t bitsForDiversifier(void* diversifier)
+        {
+            return static_cast<uint32_t>(bitwise_cast<uintptr_t>(diversifier));
+        }
+
+        ALWAYS_INLINE uint32_t currentHash(uint32_t index, void* diversifier)
+        {
+            uint64_t result;
+            bool hashFieldIsTagged = index == 0;
+            if (hashFieldIsTagged)
+                result = untagInt(m_hash, makeDiversifier(initializationNamespace, index, bitsForDiversifier(diversifier)));
+            else
+                result = m_hash;
+            return static_cast<uint32_t>(result);
+        }
+
+        ALWAYS_INLINE void setUpdatedHash(uint32_t value, uint32_t index, void* diversifier)
+        {
+            bool shouldTagHashField = index == 0;
+            if (shouldTagHashField)
+                m_hash = tagInt(static_cast<uint64_t>(value), makeDiversifier(initializationNamespace, index, bitsForDiversifier(diversifier)));
+            else
+                m_hash = value;
+        }
+
+        ARM64EHash(void* diversifier)
+        {
+            setUpdatedHash(0, 0, diversifier);
+        }
+ 
+        ALWAYS_INLINE uint32_t update(uint32_t instruction, uint32_t index, void* diversifier)
+        {
+            uint32_t currentHash = this->currentHash(index, diversifier);
+            uint64_t nextIndex = index + 1;
+            uint32_t output = nextValue(instruction, nextIndex, currentHash);
+            setUpdatedHash(output, nextIndex, diversifier);
+            return output;
         }
 
     private:
-        uint32_t m_hash;
+        uint64_t m_hash;
     };
 #endif
@@ -231 +271 @@
             , m_index(0)
 #if CPU(ARM64E)
-            , m_hash(static_cast<uint32_t>(bitwise_cast<uint64_t>(this)))
+            , m_hash(this)
             , m_hashes()
 #endif
@@ -389 +429 @@
             static_assert(sizeof(value) == 4, "");
 #if CPU(ARM64E)
-            uint32_t hash = m_hash.update(value);
+            uint32_t hash = m_hash.update(value, m_index / sizeof(IntegralType), this);
             WTF::unalignedStore<uint32_t>(m_hashes.buffer() + m_index, hash);
 #endif

trunk/Source/JavaScriptCore/assembler/LinkBuffer.cpp

@@ -246 +246 @@
     uint8_t* inData = bitwise_cast<uint8_t*>(m_assemblerStorage.buffer());
 #if CPU(ARM64E)
-    ARM64EHash verifyUncompactedHash { static_cast<uint32_t>(bitwise_cast<uint64_t>(&macroAssembler.m_assembler.buffer())) };
+    void* bufferPtr = &macroAssembler.m_assembler.buffer();
+    ARM64EHash verifyUncompactedHash { bufferPtr };
     m_assemblerHashesStorage = macroAssembler.m_assembler.buffer().releaseAssemblerHashes();
     uint32_t* inHashes = bitwise_cast<uint32_t*>(m_assemblerHashesStorage.buffer());
@@ -268 +269 @@
         InstructionType value = *ptr;
 #if CPU(ARM64E)
-        uint32_t hash = verifyUncompactedHash.update(value);
         unsigned index = (bitwise_cast<uint8_t*>(ptr) - inData) / 4;
+        uint32_t hash = verifyUncompactedHash.update(value, index, bufferPtr);
         RELEASE_ASSERT(inHashes[index] == hash);
 #endif