Changeset 44476 in webkit for trunk/JavaScriptCore/assembler

Timestamp:

Jun 5, 2009, 5:08:00 PM (16 years ago)

Author:

[email protected]

Message:

2009-06-05 Gavin Barraclough <​[email protected]>

Reviewed by Sam Weinig.

Remove patchLength..tByIdExternalLoadPrefix magic numbers from JIT.h.

These aren't really suitable values to be tracking within common code
of the JIT, since they are not (and realistically cannot) be checked
by ASSERTs, as the other repatch offsets are. Move this functionality
(skipping the REX prefix when patching load instructions to LEAs on
x86-64) into the X86Assembler.

• assembler/AbstractMacroAssembler.h: (JSC::AbstractMacroAssembler::CodeLocationInstruction::repatchLoadPtrToLEA):
• assembler/X86Assembler.h: (JSC::X86Assembler::repatchLoadPtrToLEA):
• jit/JIT.h:
• jit/JITPropertyAccess.cpp: (JSC::JIT::patchGetByIdSelf): (JSC::JIT::patchPutByIdReplace):

Location:

trunk/JavaScriptCore/assembler

Files:

• AbstractMacroAssembler.h (modified) (1 diff)
• X86Assembler.h (modified) (1 diff)

trunk/JavaScriptCore/assembler/AbstractMacroAssembler.h

@@ -460 +460 @@
         }
 
-        void repatchLoadToLEA()
-        {
-            AssemblerType::repatchLoadToLEA(this->dataLocation());
+        void repatchLoadPtrToLEA()
+        {
+            AssemblerType::repatchLoadPtrToLEA(this->dataLocation());
         }
 

trunk/JavaScriptCore/assembler/X86Assembler.h

@@ -1422 +1422 @@
     }
 
-    static void repatchLoadToLEA(void* where)
-    {
+    static void repatchLoadPtrToLEA(void* where)
+    {
+#if PLATFORM(X86_64)
+        // On x86-64 pointer memory accesses require a 64-bit operand, and as such a REX prefix.
+        // Skip over the prefix byte.
+        where = reinterpret_cast<char*>(where) + 1;
+#endif
         ExecutableAllocator::MakeWritable unprotect(where, 1);
         *reinterpret_cast<unsigned char*>(where) = static_cast<unsigned char>(OP_LEA);