Implement Harmony semantics for typeof null (behind a flag).

Harmony is intended to make typeof null === "null". This may
break existing programs. Implementing it will allow us to run
some tests on the actual web.

R=kmillikin@chromium.org
BUG=
TEST=

Review URL: http://codereview.chromium.org/7598030

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@8876 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

diff --git a/src/arm/full-codegen-arm.cc b/src/arm/full-codegen-arm.cc
index cdfc0a9..3742d16 100644 (file)
--- a/src/arm/full-codegen-arm.cc
+++ b/src/arm/full-codegen-arm.cc
@@ -4030,6 +4030,10 @@ void FullCodeGenerator::EmitLiteralCompareTypeof(Expression* expr,
     __ b(eq, if_true);
     __ CompareRoot(r0, Heap::kFalseValueRootIndex);
     Split(eq, if_true, if_false, fall_through);
+  } else if (FLAG_harmony_typeof &&
+             check->Equals(isolate()->heap()->null_symbol())) {
+    __ CompareRoot(r0, Heap::kNullValueRootIndex);
+    Split(eq, if_true, if_false, fall_through);
   } else if (check->Equals(isolate()->heap()->undefined_symbol())) {
     __ CompareRoot(r0, Heap::kUndefinedValueRootIndex);
     __ b(eq, if_true);
@@ -4047,8 +4051,10 @@ void FullCodeGenerator::EmitLiteralCompareTypeof(Expression* expr,
 
   } else if (check->Equals(isolate()->heap()->object_symbol())) {
     __ JumpIfSmi(r0, if_false);
-    __ CompareRoot(r0, Heap::kNullValueRootIndex);
-    __ b(eq, if_true);
+    if (!FLAG_harmony_typeof) {
+      __ CompareRoot(r0, Heap::kNullValueRootIndex);
+      __ b(eq, if_true);
+    }
     // Check for JS objects => true.
     __ CompareObjectType(r0, r0, r1, FIRST_NONCALLABLE_SPEC_OBJECT_TYPE);
     __ b(lt, if_false);

diff --git a/src/arm/lithium-codegen-arm.cc b/src/arm/lithium-codegen-arm.cc
index 3f3f31a..1ec5f00 100644 (file)
--- a/src/arm/lithium-codegen-arm.cc
+++ b/src/arm/lithium-codegen-arm.cc
@@ -4395,6 +4395,10 @@ Condition LCodeGen::EmitTypeofIs(Label* true_label,
     __ CompareRoot(input, Heap::kFalseValueRootIndex);
     final_branch_condition = eq;
 
+  } else if (FLAG_harmony_typeof && type_name->Equals(heap()->null_symbol())) {
+    __ CompareRoot(input, Heap::kNullValueRootIndex);
+    final_branch_condition = eq;
+
   } else if (type_name->Equals(heap()->undefined_symbol())) {
     __ CompareRoot(input, Heap::kUndefinedValueRootIndex);
     __ b(eq, true_label);
@@ -4413,8 +4417,10 @@ Condition LCodeGen::EmitTypeofIs(Label* true_label,
 
   } else if (type_name->Equals(heap()->object_symbol())) {
     __ JumpIfSmi(input, false_label);
-    __ CompareRoot(input, Heap::kNullValueRootIndex);
-    __ b(eq, true_label);
+    if (!FLAG_harmony_typeof) {
+      __ CompareRoot(input, Heap::kNullValueRootIndex);
+      __ b(eq, true_label);
+    }
     __ CompareObjectType(input, input, scratch,
                          FIRST_NONCALLABLE_SPEC_OBJECT_TYPE);
     __ b(lt, false_label);

diff --git a/src/flag-definitions.h b/src/flag-definitions.h
index 2ea9651..e315af9 100644 (file)
--- a/src/flag-definitions.h
+++ b/src/flag-definitions.h
@@ -97,6 +97,7 @@ private:
 #define FLAG FLAG_FULL
 
 // Flags for experimental language features.
+DEFINE_bool(harmony_typeof, false, "enable harmony semantics for typeof")
 DEFINE_bool(harmony_proxies, false, "enable harmony proxies")
 DEFINE_bool(harmony_weakmaps, false, "enable harmony weak maps")
 

diff --git a/src/heap.h b/src/heap.h
index 4f4ef14..03a6484 100644 (file)
--- a/src/heap.h
+++ b/src/heap.h
@@ -160,6 +160,7 @@ inline Heap* _inline_get_heap_();
   V(length_symbol, "length")                                             \
   V(name_symbol, "name")                                                 \
   V(native_symbol, "native")                                             \
+  V(null_symbol, "null")                                                 \
   V(number_symbol, "number")                                             \
   V(Number_symbol, "Number")                                             \
   V(nan_symbol, "NaN")                                                   \

diff --git a/src/ia32/full-codegen-ia32.cc b/src/ia32/full-codegen-ia32.cc
index 994c9ff..14ced5e 100644 (file)
--- a/src/ia32/full-codegen-ia32.cc
+++ b/src/ia32/full-codegen-ia32.cc
@@ -4105,6 +4105,10 @@ void FullCodeGenerator::EmitLiteralCompareTypeof(Expression* expr,
     __ j(equal, if_true);
     __ cmp(eax, isolate()->factory()->false_value());
     Split(equal, if_true, if_false, fall_through);
+  } else if (FLAG_harmony_typeof &&
+             check->Equals(isolate()->heap()->null_symbol())) {
+    __ cmp(eax, isolate()->factory()->null_value());
+    Split(equal, if_true, if_false, fall_through);
   } else if (check->Equals(isolate()->heap()->undefined_symbol())) {
     __ cmp(eax, isolate()->factory()->undefined_value());
     __ j(equal, if_true);
@@ -4120,8 +4124,10 @@ void FullCodeGenerator::EmitLiteralCompareTypeof(Expression* expr,
     Split(above_equal, if_true, if_false, fall_through);
   } else if (check->Equals(isolate()->heap()->object_symbol())) {
     __ JumpIfSmi(eax, if_false);
-    __ cmp(eax, isolate()->factory()->null_value());
-    __ j(equal, if_true);
+    if (!FLAG_harmony_typeof) {
+      __ cmp(eax, isolate()->factory()->null_value());
+      __ j(equal, if_true);
+    }
     __ CmpObjectType(eax, FIRST_NONCALLABLE_SPEC_OBJECT_TYPE, edx);
     __ j(below, if_false);
     __ CmpInstanceType(edx, LAST_NONCALLABLE_SPEC_OBJECT_TYPE);

diff --git a/src/ia32/lithium-codegen-ia32.cc b/src/ia32/lithium-codegen-ia32.cc
index c0f4e71..bbe8473 100644 (file)
--- a/src/ia32/lithium-codegen-ia32.cc
+++ b/src/ia32/lithium-codegen-ia32.cc
@@ -4200,6 +4200,10 @@ Condition LCodeGen::EmitTypeofIs(Label* true_label,
     __ cmp(input, factory()->false_value());
     final_branch_condition = equal;
 
+  } else if (FLAG_harmony_typeof && type_name->Equals(heap()->null_symbol())) {
+    __ cmp(input, factory()->null_value());
+    final_branch_condition = equal;
+
   } else if (type_name->Equals(heap()->undefined_symbol())) {
     __ cmp(input, factory()->undefined_value());
     __ j(equal, true_label);
@@ -4218,8 +4222,10 @@ Condition LCodeGen::EmitTypeofIs(Label* true_label,
 
   } else if (type_name->Equals(heap()->object_symbol())) {
     __ JumpIfSmi(input, false_label);
-    __ cmp(input, factory()->null_value());
-    __ j(equal, true_label);
+    if (!FLAG_harmony_typeof) {
+      __ cmp(input, factory()->null_value());
+      __ j(equal, true_label);
+    }
     __ CmpObjectType(input, FIRST_NONCALLABLE_SPEC_OBJECT_TYPE, input);
     __ j(below, false_label);
     __ CmpInstanceType(input, LAST_NONCALLABLE_SPEC_OBJECT_TYPE);

diff --git a/src/runtime.cc b/src/runtime.cc
index 82733a7..38199f8 100644 (file)
--- a/src/runtime.cc
+++ b/src/runtime.cc
@@ -4853,7 +4853,9 @@ RUNTIME_FUNCTION(MaybeObject*, Runtime_Typeof) {
         return isolate->heap()->boolean_symbol();
       }
       if (heap_obj->IsNull()) {
-        return isolate->heap()->object_symbol();
+        return FLAG_harmony_typeof
+            ? isolate->heap()->null_symbol()
+            : isolate->heap()->object_symbol();
       }
       ASSERT(heap_obj->IsUndefined());
       return isolate->heap()->undefined_symbol();

diff --git a/src/x64/full-codegen-x64.cc b/src/x64/full-codegen-x64.cc
index 0f7e5b3..edd9e81 100644 (file)
--- a/src/x64/full-codegen-x64.cc
+++ b/src/x64/full-codegen-x64.cc
@@ -3971,6 +3971,10 @@ void FullCodeGenerator::EmitLiteralCompareTypeof(Expression* expr,
     __ j(equal, if_true);
     __ CompareRoot(rax, Heap::kFalseValueRootIndex);
     Split(equal, if_true, if_false, fall_through);
+  } else if (FLAG_harmony_typeof &&
+             check->Equals(isolate()->heap()->null_symbol())) {
+    __ CompareRoot(rax, Heap::kNullValueRootIndex);
+    Split(equal, if_true, if_false, fall_through);
   } else if (check->Equals(isolate()->heap()->undefined_symbol())) {
     __ CompareRoot(rax, Heap::kUndefinedValueRootIndex);
     __ j(equal, if_true);
@@ -3987,8 +3991,10 @@ void FullCodeGenerator::EmitLiteralCompareTypeof(Expression* expr,
     Split(above_equal, if_true, if_false, fall_through);
   } else if (check->Equals(isolate()->heap()->object_symbol())) {
     __ JumpIfSmi(rax, if_false);
-    __ CompareRoot(rax, Heap::kNullValueRootIndex);
-    __ j(equal, if_true);
+    if (!FLAG_harmony_typeof) {
+      __ CompareRoot(rax, Heap::kNullValueRootIndex);
+      __ j(equal, if_true);
+    }
     __ CmpObjectType(rax, FIRST_NONCALLABLE_SPEC_OBJECT_TYPE, rdx);
     __ j(below, if_false);
     __ CmpInstanceType(rdx, LAST_NONCALLABLE_SPEC_OBJECT_TYPE);

diff --git a/src/x64/lithium-codegen-x64.cc b/src/x64/lithium-codegen-x64.cc
index ce6a910..99f84b5 100644 (file)
--- a/src/x64/lithium-codegen-x64.cc
+++ b/src/x64/lithium-codegen-x64.cc
@@ -4008,6 +4008,10 @@ Condition LCodeGen::EmitTypeofIs(Label* true_label,
     __ CompareRoot(input, Heap::kFalseValueRootIndex);
     final_branch_condition = equal;
 
+  } else if (FLAG_harmony_typeof && type_name->Equals(heap()->null_symbol())) {
+    __ CompareRoot(input, Heap::kNullValueRootIndex);
+    final_branch_condition = equal;
+
   } else if (type_name->Equals(heap()->undefined_symbol())) {
     __ CompareRoot(input, Heap::kUndefinedValueRootIndex);
     __ j(equal, true_label);
@@ -4025,8 +4029,10 @@ Condition LCodeGen::EmitTypeofIs(Label* true_label,
 
   } else if (type_name->Equals(heap()->object_symbol())) {
     __ JumpIfSmi(input, false_label);
-    __ CompareRoot(input, Heap::kNullValueRootIndex);
-    __ j(equal, true_label);
+    if (!FLAG_harmony_typeof) {
+      __ CompareRoot(input, Heap::kNullValueRootIndex);
+      __ j(equal, true_label);
+    }
     __ CmpObjectType(input, FIRST_NONCALLABLE_SPEC_OBJECT_TYPE, input);
     __ j(below, false_label);
     __ CmpInstanceType(input, LAST_NONCALLABLE_SPEC_OBJECT_TYPE);

diff --git a/test/mjsunit/harmony/typeof.js b/test/mjsunit/harmony/typeof.js
new file mode 100644 (file)
index 0000000..acde977
--- /dev/null
+++ b/test/mjsunit/harmony/typeof.js
@@ -0,0 +1,35 @@
+// Copyright 2011 the V8 project authors. All rights reserved.
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+//       notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+//       copyright notice, this list of conditions and the following
+//       disclaimer in the documentation and/or other materials provided
+//       with the distribution.
+//     * Neither the name of Google Inc. nor the names of its
+//       contributors may be used to endorse or promote products derived
+//       from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// Flags: --harmony-typeof
+
+assertFalse(typeof null == 'object')
+assertFalse(typeof null === 'object')
+assertTrue(typeof null == 'null')
+assertTrue(typeof null === 'null')
+assertEquals("null", typeof null)
+assertSame("null", typeof null)