Changeset 37406 in webkit for trunk/JavaScriptCore/VM/CTI.cpp

Timestamp:

Oct 7, 2008, 9:56:38 PM (17 years ago)

Author:

[email protected]

Message:

Switch CTI runtime calls to the fastcall calling convention

Reviewed by Cameron Zwarich

Basically this means that we get to store the argument for CTI
calls in the ECX register, which saves a register->memory write
and subsequent memory->register read.

This is a 1.7% progression in SunSpider and 2.4% on commandline
v8 tests on Windows

File:

• trunk/JavaScriptCore/VM/CTI.cpp (modified) (5 diffs)

trunk/JavaScriptCore/VM/CTI.cpp

@@ -113 +113 @@
             sub esp, 0x24;
             mov esi, 512;
-            mov [esp], esp;
+            mov ecx, esp;
             mov edi, [esp + 0x38];
             call [esp + 0x30];
@@ -126 +126 @@
     {
         __asm {
-            mov [esp], esp;
+            mov ecx, esp;
             call JSC::Machine::cti_vm_throw;
             add esp, 0x24;
@@ -2796 +2796 @@
 extern "C" {
 
-static JSValue* SFX_CALL transitionObject(StructureID* newStructureID, size_t cachedOffset, JSObject* baseObject, JSValue* value)
+static JSValue* transitionObject(StructureID* newStructureID, size_t cachedOffset, JSObject* baseObject, JSValue* value)
 {
     baseObject->transitionTo(newStructureID);
@@ -2872 +2872 @@
     }
     m_jit.ret();
+    
+    X86Assembler::JmpSrc failureJump;
+    if (failureCases.size()) {
+        for (unsigned i = 0; i < failureCases.size(); ++i)
+            m_jit.link(failureCases[i], m_jit.label());
+        m_jit.emitRestoreArgumentReferenceForTrampoline();
+        failureJump = m_jit.emitUnlinkedJmp();
+    }
+
     void* code = m_jit.copy();
     ASSERT(code);
-    
-    for (unsigned i = 0; i < failureCases.size(); ++i)
-        X86Assembler::link(code, failureCases[i], reinterpret_cast<void*>(Machine::cti_op_put_by_id_fail));
+
+    if (failureCases.size())
+        X86Assembler::link(code, failureJump, reinterpret_cast<void*>(Machine::cti_op_put_by_id_fail));
 
     if (transitionWillNeedStorageRealloc(oldStructureID, newStructureID))
@@ -2986 +2995 @@
 
     m_jit.addl_rr(X86::ecx, X86::ecx);
-    X86Assembler::JmpSrc failureCases3 = m_jit.emitUnlinkedJo();
+    X86Assembler::JmpSrc failureClobberedECX = m_jit.emitUnlinkedJo();
     m_jit.addl_i8r(1, X86::ecx);
 
     X86Assembler::JmpSrc success = m_jit.emitUnlinkedJmp();
+
+    m_jit.link(failureClobberedECX, m_jit.label());
+    m_jit.emitRestoreArgumentReference();
+    X86Assembler::JmpSrc failureCases3 = m_jit.emitUnlinkedJmp();
 
     void* code = m_jit.copy();