Generate inline code for contextual loads.

src/ia32/codegen-ia32.cc

Index: src/ia32/codegen-ia32.cc
diff --git a/src/ia32/codegen-ia32.cc b/src/ia32/codegen-ia32.cc
index 86f3877c7e8cdc824793c7956363be47e3fa34c6..738450d2d7bef1353a1f43bb34104fca8c8a6095 100644
--- a/src/ia32/codegen-ia32.cc
+++ b/src/ia32/codegen-ia32.cc
@@ -9144,9 +9144,15 @@ class DeferredReferenceGetNamedValue: public DeferredCode {
  public:
   DeferredReferenceGetNamedValue(Register dst,
                                  Register receiver,
-                                 Handle<String> name)
-      : dst_(dst), receiver_(receiver),  name_(name) {
-    set_comment("[ DeferredReferenceGetNamedValue");
+                                 Handle<String> name,
+                                 bool is_contextual)
+      : dst_(dst),
+        receiver_(receiver),
+        name_(name),
+        is_contextual_(is_contextual) {
+    set_comment(is_contextual
+                ? "[ DeferredReferenceGetNamedValue (contextual)"
+                : "[ DeferredReferenceGetNamedValue");
   }
 
   virtual void Generate();
@@ -9158,6 +9164,7 @@ class DeferredReferenceGetNamedValue: public DeferredCode {
   Register dst_;
   Register receiver_;
   Handle<String> name_;
+  bool is_contextual_;
 };
 
 
@@ -9167,9 +9174,15 @@ void DeferredReferenceGetNamedValue::Generate() {
   }
   __ Set(ecx, Immediate(name_));
   Handle<Code> ic(Builtins::builtin(Builtins::LoadIC_Initialize));
-  __ call(ic, RelocInfo::CODE_TARGET);
-  // The call must be followed by a test eax instruction to indicate
-  // that the inobject property case was inlined.
+  RelocInfo::Mode mode = is_contextual_
+      ? RelocInfo::CODE_TARGET_CONTEXT
+      : RelocInfo::CODE_TARGET;
+  __ call(ic, mode);
+  // The call must be followed by:
+  // - a test eax instruction to indicate that the inobject property
+  //   case was inlined.
+  // - a mov ecx instruction to indicate that the contextual property
+  //   load was inlined.
   //
   // Store the delta to the map check instruction here in the test
   // instruction.  Use masm_-> instead of the __ macro since the
@@ -9177,8 +9190,13 @@ void DeferredReferenceGetNamedValue::Generate() {
   int delta_to_patch_site = masm_->SizeOfCodeGeneratedSince(patch_site());
   // Here we use masm_-> instead of the __ macro because this is the
   // instruction that gets patched and coverage code gets in the way.
-  masm_->test(eax, Immediate(-delta_to_patch_site));
-  __ IncrementCounter(&Counters::named_load_inline_miss, 1);
+  if (is_contextual_) {
+    masm_->mov(ecx, -delta_to_patch_site);
+    __ IncrementCounter(&Counters::named_load_global_inline_miss, 1);
+  } else {
+    masm_->test(eax, Immediate(-delta_to_patch_site));
+    __ IncrementCounter(&Counters::named_load_inline_miss, 1);
+  }
 
   if (!dst_.is(eax)) __ mov(dst_, eax);
 }
@@ -9349,12 +9367,17 @@ Result CodeGenerator::EmitNamedLoad(Handle<String> name, bool is_contextual) {
 #ifdef DEBUG
   int original_height = frame()->height();
 #endif
+
+  bool contextual_load_in_builtin =
+      is_contextual &&
+      (Bootstrapper::IsActive() ||
+       (!info_->closure().is_null() && info_->closure()->IsBuiltin()));
+
   Result result;
-  // Do not inline the inobject property case for loads from the global
-  // object.  Also do not inline for unoptimized code.  This saves time in
-  // the code generator.  Unoptimized code is toplevel code or code that is
-  // not in a loop.
-  if (is_contextual || scope()->is_global_scope() || loop_nesting() == 0) {
+  // Do not inline in the global code or when not in loop.
+  if (scope()->is_global_scope() ||
+      loop_nesting() == 0 ||
+      contextual_load_in_builtin) {
     Comment cmnt(masm(), "[ Load from named Property");
     frame()->Push(name);
 
@@ -9367,19 +9390,26 @@ Result CodeGenerator::EmitNamedLoad(Handle<String> name, bool is_contextual) {
     // instruction here.
     __ nop();
   } else {
-    // Inline the inobject property case.
-    Comment cmnt(masm(), "[ Inlined named property load");
+    // Inline the property load.
+    Comment cmnt(masm(), is_contextual
+                         ? "[ Inlined contextual property load"
+                         : "[ Inlined named property load");
     Result receiver = frame()->Pop();
     receiver.ToRegister();
 
     result = allocator()->Allocate();
     ASSERT(result.is_valid());
     DeferredReferenceGetNamedValue* deferred =
-        new DeferredReferenceGetNamedValue(result.reg(), receiver.reg(), name);
+        new DeferredReferenceGetNamedValue(result.reg(),
+                                           receiver.reg(),
+                                           name,
+                                           is_contextual);
 
-    // Check that the receiver is a heap object.
-    __ test(receiver.reg(), Immediate(kSmiTagMask));
-    deferred->Branch(zero);
+    if (!is_contextual) {
+      // Check that the receiver is a heap object.
+      __ test(receiver.reg(), Immediate(kSmiTagMask));
+      deferred->Branch(zero);
+    }
 
     __ bind(deferred->patch_site());
     // This is the map check instruction that will be patched (so we can't
@@ -9391,17 +9421,28 @@ Result CodeGenerator::EmitNamedLoad(Handle<String> name, bool is_contextual) {
     // which allows the assert below to succeed and patching to work.
     deferred->Branch(not_equal);
 
-    // The delta from the patch label to the load offset must be statically
-    // known.
+    // The delta from the patch label to the actual load must be
+    // statically known.
     ASSERT(masm()->SizeOfCodeGeneratedSince(deferred->patch_site()) ==
            LoadIC::kOffsetToLoadInstruction);
-    // The initial (invalid) offset has to be large enough to force a 32-bit
-    // instruction encoding to allow patching with an arbitrary offset.  Use
-    // kMaxInt (minus kHeapObjectTag).
-    int offset = kMaxInt;
-    masm()->mov(result.reg(), FieldOperand(receiver.reg(), offset));
 
-    __ IncrementCounter(&Counters::named_load_inline, 1);
+    if (is_contextual) {
+      // Load the (initialy invalid) cell and get its value.
+      masm()->mov(result.reg(), Factory::null_value());

[Søren Thygesen Gjesse, 2010/09/20 06:50:08]

How about having a --debug-code guarded assert here that result.reg() is never
null when this code is actually run.

+      __ mov(result.reg(),
+             FieldOperand(result.reg(), JSGlobalPropertyCell::kValueOffset));
+      __ cmp(result.reg(), Factory::the_hole_value());
+      deferred->Branch(equal);
+      __ IncrementCounter(&Counters::named_load_global_inline, 1);
+    } else {
+      // The initial (invalid) offset has to be large enough to force a 32-bit
+      // instruction encoding to allow patching with an arbitrary offset.  Use
+      // kMaxInt (minus kHeapObjectTag).
+      int offset = kMaxInt;
+      masm()->mov(result.reg(), FieldOperand(receiver.reg(), offset));
+      __ IncrementCounter(&Counters::named_load_inline, 1);
+    }
+
     deferred->BindExit();
   }
   ASSERT(frame()->height() == original_height - 1);