Changeset 236880 in webkit

Timestamp:

Oct 5, 2018, 11:33:41 AM (7 years ago)

Author:

mark.lam@apple.com

Message:

performJITMemcpy() should handle the case when the executable allocator is not initialized yet.
​https://bugs.webkit.org/show_bug.cgi?id=190317
<rdar://problem/45039398>

Reviewed by Saam Barati.

When SeparatedWXHeaps is in use, jitWriteThunkGenerator() will call performJITMemcpy()
to copy memory before the JIT fixed memory pool is initialize. Before r236864,
performJITMemcpy() would just do a memcpy in that case. We need to restore the
equivalent behavior.

• jit/ExecutableAllocator.cpp:

(JSC::isJITPC):

• jit/ExecutableAllocator.h:

(JSC::performJITMemcpy):

Location:

trunk/Source/JavaScriptCore

Files:

• ChangeLog (modified) (1 diff)
• jit/ExecutableAllocator.cpp (modified) (3 diffs)
• jit/ExecutableAllocator.h (modified) (1 diff)

trunk/Source/JavaScriptCore/ChangeLog

@@ +1 @@
+2018-10-05  Mark Lam  <mark.lam@apple.com>
+
+        performJITMemcpy() should handle the case when the executable allocator is not initialized yet.
+        https://bugs.webkit.org/show_bug.cgi?id=190317
+        <rdar://problem/45039398>
+
+        Reviewed by Saam Barati.
+
+        When SeparatedWXHeaps is in use, jitWriteThunkGenerator() will call performJITMemcpy()
+        to copy memory before the JIT fixed memory pool is initialize.  Before r236864,
+        performJITMemcpy() would just do a memcpy in that case.  We need to restore the
+        equivalent behavior.
+
+        * jit/ExecutableAllocator.cpp:
+        (JSC::isJITPC):
+        * jit/ExecutableAllocator.h:
+        (JSC::performJITMemcpy):
+
 2018-10-05  Carlos Eduardo Ramalho  <cadubentzen@gmail.com>
 

trunk/Source/JavaScriptCore/jit/ExecutableAllocator.cpp

@@ -332 +332 @@
         return linkBuffer.finalizeCodeWithoutDisassembly<JITThunkPtrTag>();
     }
-#else // CPU(ARM64) && USE(EXECUTE_ONLY_JIT_WRITE_FUNCTION)
+#else // not CPU(ARM64) && USE(EXECUTE_ONLY_JIT_WRITE_FUNCTION)
     static void genericWriteToJITRegion(off_t offset, const void* data, size_t dataSize)
     {
@@ -351 +351 @@
         return MacroAssemblerCodeRef<JITThunkPtrTag>::createSelfManagedCodeRef(codePtr);
     }
-#endif
+#endif // CPU(ARM64) && USE(EXECUTE_ONLY_JIT_WRITE_FUNCTION)
 
 #else // OS(DARWIN) && HAVE(REMAP_JIT)
@@ -510 +510 @@
 bool isJITPC(void* pc)
 {
-    return allocator->isJITPC(pc);
+    return allocator && allocator->isJITPC(pc);
 }
 

trunk/Source/JavaScriptCore/jit/ExecutableAllocator.h

@@ -94 +94 @@
     RELEASE_ASSERT(roundUpToMultipleOf<instructionSize>(src) == src);
 #endif
-    if (dst >= startOfFixedExecutableMemoryPool() && dst < endOfFixedExecutableMemoryPool()) {
+    if (isJITPC(dst)) {
         RELEASE_ASSERT(reinterpret_cast<uint8_t*>(dst) + n <= endOfFixedExecutableMemoryPool());
 #if ENABLE(FAST_JIT_PERMISSIONS)