Make kAsciiDataHintTag have correct semantics for all both 1 and 2 byte string types.

BUG=

Review URL: https://chromiumcodereview.appspot.com/11361171

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@12937 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/arm/code-stubs-arm.cc

@@ -6498,11 +6498,6 @@ void StringAddStub::Generate(MacroAssembler* masm) {
   __ tst(r4, Operand(kAsciiDataHintMask));
   __ tst(r5, Operand(kAsciiDataHintMask), ne);
   __ b(ne, &ascii_data);
-  __ eor(r4, r4, Operand(r5));
-  STATIC_ASSERT(kOneByteStringTag != 0 && kAsciiDataHintTag != 0);
-  __ and_(r4, r4, Operand(kOneByteStringTag | kAsciiDataHintTag));
-  __ cmp(r4, Operand(kOneByteStringTag | kAsciiDataHintTag));
-  __ b(eq, &ascii_data);
 
   // Allocate a two byte cons string.
   __ AllocateTwoByteConsString(r7, r6, r4, r5, &call_runtime);

src/ia32/code-stubs-ia32.cc

@@ -5748,13 +5748,6 @@ void StringAddStub::Generate(MacroAssembler* masm) {
   // edi: second instance type.
   __ test(ecx, Immediate(kAsciiDataHintMask));
   __ j(not_zero, &ascii_data);
-  __ mov(ecx, FieldOperand(eax, HeapObject::kMapOffset));
-  __ movzx_b(ecx, FieldOperand(ecx, Map::kInstanceTypeOffset));
-  __ xor_(edi, ecx);
-  STATIC_ASSERT(kOneByteStringTag != 0 && kAsciiDataHintTag != 0);
-  __ and_(edi, kOneByteStringTag | kAsciiDataHintTag);
-  __ cmp(edi, kOneByteStringTag | kAsciiDataHintTag);
-  __ j(equal, &ascii_data);
   // Allocate a two byte cons string.
   __ AllocateTwoByteConsString(ecx, edi, no_reg, &call_runtime);
   __ jmp(&allocated);

src/objects-inl.h

@@ -333,8 +333,7 @@ bool String::IsTwoByteRepresentationUnderneath() {
 
 bool String::HasOnlyAsciiChars() {
   uint32_t type = map()->instance_type();
-  return (type & kStringEncodingMask) == kOneByteStringTag ||
-         (type & kAsciiDataHintMask) == kAsciiDataHintTag;
+  return (type & kAsciiDataHintMask) == kAsciiDataHintTag;
 }
 
 

src/objects.h

@@ -530,39 +530,46 @@ const uint32_t kShortcutTypeTag = kConsStringTag;
 enum InstanceType {
   // String types.
   SYMBOL_TYPE = kTwoByteStringTag | kSymbolTag | kSeqStringTag,
-  ASCII_SYMBOL_TYPE = kOneByteStringTag | kSymbolTag | kSeqStringTag,
+  ASCII_SYMBOL_TYPE = kOneByteStringTag | kAsciiDataHintTag | kSymbolTag |
+                      kSeqStringTag,
   CONS_SYMBOL_TYPE = kTwoByteStringTag | kSymbolTag | kConsStringTag,
-  CONS_ASCII_SYMBOL_TYPE = kOneByteStringTag | kSymbolTag | kConsStringTag,
+  CONS_ASCII_SYMBOL_TYPE = kOneByteStringTag | kAsciiDataHintTag | kSymbolTag |
+                           kConsStringTag,
   SHORT_EXTERNAL_SYMBOL_TYPE = kTwoByteStringTag | kSymbolTag |
                                kExternalStringTag | kShortExternalStringTag,
   SHORT_EXTERNAL_SYMBOL_WITH_ASCII_DATA_TYPE =
       kTwoByteStringTag | kSymbolTag | kExternalStringTag |
       kAsciiDataHintTag | kShortExternalStringTag,
-  SHORT_EXTERNAL_ASCII_SYMBOL_TYPE = kOneByteStringTag | kExternalStringTag |
-                                     kSymbolTag | kShortExternalStringTag,
+  SHORT_EXTERNAL_ASCII_SYMBOL_TYPE = kOneByteStringTag | kAsciiDataHintTag |
+                                     kExternalStringTag | kSymbolTag |
+                                     kShortExternalStringTag,
   EXTERNAL_SYMBOL_TYPE = kTwoByteStringTag | kSymbolTag | kExternalStringTag,
   EXTERNAL_SYMBOL_WITH_ASCII_DATA_TYPE =
       kTwoByteStringTag | kSymbolTag | kExternalStringTag | kAsciiDataHintTag,
   EXTERNAL_ASCII_SYMBOL_TYPE =
-      kOneByteStringTag | kSymbolTag | kExternalStringTag,
+      kOneByteStringTag | kAsciiDataHintTag | kSymbolTag | kExternalStringTag,
   STRING_TYPE = kTwoByteStringTag | kSeqStringTag,
-  ASCII_STRING_TYPE = kOneByteStringTag | kSeqStringTag,
+  ASCII_STRING_TYPE = kOneByteStringTag | kAsciiDataHintTag | kSeqStringTag,
   CONS_STRING_TYPE = kTwoByteStringTag | kConsStringTag,
-  CONS_ASCII_STRING_TYPE = kOneByteStringTag | kConsStringTag,
+  CONS_ASCII_STRING_TYPE =
+      kOneByteStringTag | kAsciiDataHintTag | kConsStringTag,
   SLICED_STRING_TYPE = kTwoByteStringTag | kSlicedStringTag,
-  SLICED_ASCII_STRING_TYPE = kOneByteStringTag | kSlicedStringTag,
+  SLICED_ASCII_STRING_TYPE =
+      kOneByteStringTag | kAsciiDataHintTag | kSlicedStringTag,
   SHORT_EXTERNAL_STRING_TYPE =
       kTwoByteStringTag | kExternalStringTag | kShortExternalStringTag,
   SHORT_EXTERNAL_STRING_WITH_ASCII_DATA_TYPE =
       kTwoByteStringTag | kExternalStringTag |
       kAsciiDataHintTag | kShortExternalStringTag,
   SHORT_EXTERNAL_ASCII_STRING_TYPE =
-      kOneByteStringTag | kExternalStringTag | kShortExternalStringTag,
+      kOneByteStringTag | kAsciiDataHintTag |
+      kExternalStringTag | kShortExternalStringTag,
   EXTERNAL_STRING_TYPE = kTwoByteStringTag | kExternalStringTag,
   EXTERNAL_STRING_WITH_ASCII_DATA_TYPE =
       kTwoByteStringTag | kExternalStringTag | kAsciiDataHintTag,
   // LAST_STRING_TYPE
-  EXTERNAL_ASCII_STRING_TYPE = kOneByteStringTag | kExternalStringTag,
+  EXTERNAL_ASCII_STRING_TYPE =
+      kOneByteStringTag | kAsciiDataHintTag | kExternalStringTag,
   PRIVATE_EXTERNAL_ASCII_STRING_TYPE = EXTERNAL_ASCII_STRING_TYPE,
 
   // Objects allocated in their own spaces (never in new space).

src/x64/code-stubs-x64.cc

@@ -4765,11 +4765,6 @@ void StringAddStub::Generate(MacroAssembler* masm) {
   // r9: second instance type.
   __ testb(rcx, Immediate(kAsciiDataHintMask));
   __ j(not_zero, &ascii_data);
-  __ xor_(r8, r9);
-  STATIC_ASSERT(kOneByteStringTag != 0 && kAsciiDataHintTag != 0);
-  __ andb(r8, Immediate(kOneByteStringTag | kAsciiDataHintTag));
-  __ cmpb(r8, Immediate(kOneByteStringTag | kAsciiDataHintTag));
-  __ j(equal, &ascii_data);
   // Allocate a two byte cons string.
   __ AllocateTwoByteConsString(rcx, rdi, no_reg, &call_runtime);
   __ jmp(&allocated);