Fast string construct stub (ia32 only for now).

Review URL: http://codereview.chromium.org/3211002

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@5357 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/arm/builtins-arm.cc

@@ -481,6 +481,13 @@ void Builtins::Generate_ArrayConstructCode(MacroAssembler* masm) {
 }
 
 
+void Builtins::Generate_StringConstructCode(MacroAssembler* masm) {
+  // TODO(849): implement custom construct stub.
+  // Generate a copy of the generic stub for now.
+  Generate_JSConstructStubGeneric(masm);
+}
+
+
 void Builtins::Generate_JSConstructCall(MacroAssembler* masm) {
   // ----------- S t a t e -------------
   //  -- r0     : number of arguments

src/bootstrapper.cc

@@ -720,6 +720,8 @@ void Genesis::InitializeGlobal(Handle<GlobalObject> inner_global,
         InstallFunction(global, "String", JS_VALUE_TYPE, JSValue::kSize,
                         Top::initial_object_prototype(), Builtins::Illegal,
                         true);
+    string_fun->shared()->set_construct_stub(
+        Builtins::builtin(Builtins::StringConstructCode));
     global_context()->set_string_function(*string_fun);
     // Add 'length' property to strings.
     Handle<DescriptorArray> string_descriptors =

src/builtins.h

@@ -117,7 +117,10 @@ enum BuiltinExtraArguments {
   V(FunctionApply,              BUILTIN, UNINITIALIZED)                   \
                                                                           \
   V(ArrayCode,                  BUILTIN, UNINITIALIZED)                   \
-  V(ArrayConstructCode,         BUILTIN, UNINITIALIZED)
+  V(ArrayConstructCode,         BUILTIN, UNINITIALIZED)                   \
+                                                                          \
+  V(StringConstructCode,        BUILTIN, UNINITIALIZED)
+
 
 #ifdef ENABLE_DEBUGGER_SUPPORT
 // Define list of builtins used by the debugger implemented in assembly.
@@ -258,6 +261,8 @@ class Builtins : public AllStatic {
 
   static void Generate_ArrayCode(MacroAssembler* masm);
   static void Generate_ArrayConstructCode(MacroAssembler* masm);
+
+  static void Generate_StringConstructCode(MacroAssembler* masm);
 };
 
 } }  // namespace v8::internal

src/ia32/builtins-ia32.cc

@@ -29,6 +29,7 @@
 
 #if defined(V8_TARGET_ARCH_IA32)
 
+#include "code-stubs-ia32.h"
 #include "codegen-inl.h"
 
 namespace v8 {
@@ -695,17 +696,6 @@ void Builtins::Generate_FunctionApply(MacroAssembler* masm) {
 }
 
 
-// Load the built-in Array function from the current context.
-static void GenerateLoadArrayFunction(MacroAssembler* masm, Register result) {
-  // Load the global context.
-  __ mov(result, Operand(esi, Context::SlotOffset(Context::GLOBAL_INDEX)));
-  __ mov(result, FieldOperand(result, GlobalObject::kGlobalContextOffset));
-  // Load the Array function from the global context.
-  __ mov(result,
-         Operand(result, Context::SlotOffset(Context::ARRAY_FUNCTION_INDEX)));
-}
-
-
 // Number of empty elements to allocate for an empty array.
 static const int kPreallocatedArrayElements = 4;
 
@@ -1095,7 +1085,7 @@ void Builtins::Generate_ArrayCode(MacroAssembler* masm) {
   Label generic_array_code;
 
   // Get the Array function.
-  GenerateLoadArrayFunction(masm, edi);
+  __ LoadGlobalFunction(Context::ARRAY_FUNCTION_INDEX, edi);
 
   if (FLAG_debug_code) {
     // Initial map for the builtin Array function shoud be a map.
@@ -1131,7 +1121,7 @@ void Builtins::Generate_ArrayConstructCode(MacroAssembler* masm) {
   if (FLAG_debug_code) {
     // The array construct code is only set for the builtin Array function which
     // does always have a map.
-    GenerateLoadArrayFunction(masm, ebx);
+    __ LoadGlobalFunction(Context::ARRAY_FUNCTION_INDEX, ebx);
     __ cmp(edi, Operand(ebx));
     __ Assert(equal, "Unexpected Array function");
     // Initial map for the builtin Array function should be a map.
@@ -1155,6 +1145,131 @@ void Builtins::Generate_ArrayConstructCode(MacroAssembler* masm) {
 }
 
 
+void Builtins::Generate_StringConstructCode(MacroAssembler* masm) {
+  // ----------- S t a t e -------------
+  //  -- eax                 : number of arguments
+  //  -- edi                 : constructor function
+  //  -- esp[0]              : return address
+  //  -- esp[(argc - n) * 4] : arg[n] (zero-based)
+  //  -- esp[(argc + 1) * 4] : receiver
+  // -----------------------------------
+  __ IncrementCounter(&Counters::string_ctor_calls, 1);
+
+  if (FLAG_debug_code) {
+    __ LoadGlobalFunction(Context::STRING_FUNCTION_INDEX, ecx);
+    __ cmp(edi, Operand(ecx));
+    __ Assert(equal, "Unexpected String function");
+  }
+
+  // Load the first argument into eax and get rid of the rest
+  // (including the receiver).
+  Label no_arguments;
+  __ test(eax, Operand(eax));
+  __ j(zero, &no_arguments);
+  __ mov(ebx, Operand(esp, eax, times_pointer_size, 0));
+  __ pop(ecx);
+  __ lea(esp, Operand(esp, eax, times_pointer_size, kPointerSize));
+  __ push(ecx);
+  __ mov(eax, ebx);
+
+  // Lookup the argument in the number to string cache.
+  Label not_cached, argument_is_string;
+  NumberToStringStub::GenerateLookupNumberStringCache(
+      masm,
+      eax,  // Input.
+      ebx,  // Result.
+      ecx,  // Scratch 1.
+      edx,  // Scratch 2.
+      false,  // Input is known to be smi?
+      &not_cached);
+  __ IncrementCounter(&Counters::string_ctor_cached_number, 1);
+  __ bind(&argument_is_string);
+  // ----------- S t a t e -------------
+  //  -- ebx    : argument converted to string
+  //  -- edi    : constructor function
+  //  -- esp[0] : return address
+  // -----------------------------------
+
+  // Allocate a JSValue and put the tagged pointer into eax.
+  Label gc_required;
+  __ AllocateInNewSpace(JSValue::kSize,
+                        eax,  // Result.
+                        ecx,  // New allocation top (we ignore it).
+                        no_reg,
+                        &gc_required,
+                        TAG_OBJECT);
+
+  // Set the map.
+  __ LoadGlobalFunctionInitialMap(edi, ecx);
+  if (FLAG_debug_code) {
+    __ cmpb(FieldOperand(ecx, Map::kInstanceSizeOffset),
+            JSValue::kSize >> kPointerSizeLog2);
+    __ Assert(equal, "Unexpected string wrapper instance size");
+    __ cmpb(FieldOperand(ecx, Map::kUnusedPropertyFieldsOffset), 0);
+    __ Assert(equal, "Unexpected unused properties of string wrapper");
+  }
+  __ mov(FieldOperand(eax, HeapObject::kMapOffset), ecx);
+
+  // Set properties and elements.
+  __ Set(ecx, Immediate(Factory::empty_fixed_array()));
+  __ mov(FieldOperand(eax, JSObject::kPropertiesOffset), ecx);
+  __ mov(FieldOperand(eax, JSObject::kElementsOffset), ecx);
+
+  // Set the value.
+  __ mov(FieldOperand(eax, JSValue::kValueOffset), ebx);
+
+  // Ensure the object is fully initialized.
+  STATIC_ASSERT(JSValue::kSize == 4 * kPointerSize);
+
+  // We're done. Return.
+  __ ret(0);
+
+  // The argument was not found in the number to string cache. Check
+  // if it's a string already before calling the conversion builtin.
+  Label convert_argument;
+  __ bind(&not_cached);
+  STATIC_ASSERT(kSmiTag == 0);
+  __ test(eax, Immediate(kSmiTagMask));
+  __ j(zero, &convert_argument);
+  Condition is_string = masm->IsObjectStringType(eax, ebx, ecx);
+  __ j(NegateCondition(is_string), &convert_argument);
+  __ mov(ebx, eax);
+  __ IncrementCounter(&Counters::string_ctor_string_value, 1);
+  __ jmp(&argument_is_string);
+
+  // Invoke the conversion builtin and put the result into ebx.
+  __ bind(&convert_argument);
+  __ IncrementCounter(&Counters::string_ctor_conversions, 1);
+  __ EnterInternalFrame();
+  __ push(edi);  // Preserve the function.
+  __ push(eax);
+  __ InvokeBuiltin(Builtins::TO_STRING, CALL_FUNCTION);
+  __ pop(edi);
+  __ LeaveInternalFrame();
+  __ mov(ebx, eax);
+  __ jmp(&argument_is_string);
+
+  // Load the empty string into ebx, remove the receiver from the
+  // stack, and jump back to the case where the argument is a string.
+  __ bind(&no_arguments);
+  __ Set(ebx, Immediate(Factory::empty_string()));
+  __ pop(ecx);
+  __ lea(esp, Operand(esp, kPointerSize));
+  __ push(ecx);
+  __ jmp(&argument_is_string);
+
+  // At this point the argument is already a string. Call runtime to
+  // create a string wrapper.
+  __ bind(&gc_required);
+  __ IncrementCounter(&Counters::string_ctor_gc_required, 1);
+  __ EnterInternalFrame();
+  __ push(ebx);
+  __ CallRuntime(Runtime::kNewStringWrapper, 1);
+  __ LeaveInternalFrame();
+  __ ret(0);
+}
+
+
 static void EnterArgumentsAdaptorFrame(MacroAssembler* masm) {
   __ push(ebp);
   __ mov(ebp, Operand(esp));

src/ia32/macro-assembler-ia32.cc

@@ -1369,6 +1369,30 @@ void MacroAssembler::LoadContext(Register dst, int context_chain_length) {
 }
 
 
+void MacroAssembler::LoadGlobalFunction(int index, Register function) {
+  // Load the global or builtins object from the current context.
+  mov(function, Operand(esi, Context::SlotOffset(Context::GLOBAL_INDEX)));
+  // Load the global context from the global or builtins object.
+  mov(function, FieldOperand(function, GlobalObject::kGlobalContextOffset));
+  // Load the function from the global context.
+  mov(function, Operand(function, Context::SlotOffset(index)));
+}
+
+
+void MacroAssembler::LoadGlobalFunctionInitialMap(Register function,
+                                                  Register map) {
+  // Load the initial map.  The global functions all have initial maps.
+  mov(map, FieldOperand(function, JSFunction::kPrototypeOrInitialMapOffset));
+  if (FLAG_debug_code) {
+    Label ok, fail;
+    CheckMap(map, Factory::meta_map(), &fail, false);
+    jmp(&ok);
+    bind(&fail);
+    Abort("Global functions must have initial map");
+    bind(&ok);
+  }
+}
+
 
 void MacroAssembler::Ret() {
   ret(0);

src/ia32/macro-assembler-ia32.h

@@ -140,6 +140,13 @@ class MacroAssembler: public Assembler {
   // Find the function context up the context chain.
   void LoadContext(Register dst, int context_chain_length);
 
+  // Load the global function with the given index.
+  void LoadGlobalFunction(int index, Register function);
+
+  // Load the initial map from the global function. The registers
+  // function and map can be the same.
+  void LoadGlobalFunctionInitialMap(Register function, Register map);
+
   // ---------------------------------------------------------------------------
   // JavaScript invokes
 

src/ia32/stub-cache-ia32.cc

@@ -257,16 +257,8 @@ void StubCache::GenerateProbe(MacroAssembler* masm,
 void StubCompiler::GenerateLoadGlobalFunctionPrototype(MacroAssembler* masm,
                                                        int index,
                                                        Register prototype) {
-  // Load the global or builtins object from the current context.
-  __ mov(prototype, Operand(esi, Context::SlotOffset(Context::GLOBAL_INDEX)));
-  // Load the global context from the global or builtins object.
-  __ mov(prototype,
-         FieldOperand(prototype, GlobalObject::kGlobalContextOffset));
-  // Load the function from the global context.
-  __ mov(prototype, Operand(prototype, Context::SlotOffset(index)));
-  // Load the initial map.  The global functions all have initial maps.
-  __ mov(prototype,
-         FieldOperand(prototype, JSFunction::kPrototypeOrInitialMapOffset));
+  __ LoadGlobalFunction(index, prototype);
+  __ LoadGlobalFunctionInitialMap(prototype, prototype);
   // Load the prototype from the initial map.
   __ mov(prototype, FieldOperand(prototype, Map::kPrototypeOffset));
 }

src/runtime.cc

@@ -5575,6 +5575,14 @@ static Object* Runtime_StringToArray(Arguments args) {
 }
 
 
+static Object* Runtime_NewStringWrapper(Arguments args) {
+  NoHandleAllocation ha;
+  ASSERT(args.length() == 1);
+  CONVERT_CHECKED(String, value, args[0]);
+  return value->ToObject();
+}
+
+
 bool Runtime::IsUpperCaseChar(uint16_t ch) {
   unibrow::uchar chars[unibrow::ToUppercase::kMaxWidth];
   int char_length = to_upper_mapping.get(ch, 0, chars);

src/runtime.h

@@ -174,6 +174,7 @@ namespace internal {
   F(StringMatch, 3, 1) \
   F(StringTrim, 3, 1) \
   F(StringToArray, 1, 1) \
+  F(NewStringWrapper, 1, 1) \
   \
   /* Numbers */ \
   F(NumberToRadixString, 2, 1) \

src/v8-counters.h

@@ -85,6 +85,11 @@ namespace internal {
   SC(compilation_cache_misses, V8.CompilationCacheMisses)             \
   SC(regexp_cache_hits, V8.RegExpCacheHits)                           \
   SC(regexp_cache_misses, V8.RegExpCacheMisses)                       \
+  SC(string_ctor_calls, V8.StringConstructorCalls)                    \
+  SC(string_ctor_conversions, V8.StringConstructorConversions)        \
+  SC(string_ctor_cached_number, V8.StringConstructorCachedNumber)     \
+  SC(string_ctor_string_value, V8.StringConstructorStringValue)       \
+  SC(string_ctor_gc_required, V8.StringConstructorGCRequired)         \
   /* Amount of evaled source code. */                                 \
   SC(total_eval_size, V8.TotalEvalSize)                               \
   /* Amount of loaded source code. */                                 \

src/x64/builtins-x64.cc

@@ -875,6 +875,13 @@ void Builtins::Generate_ArrayConstructCode(MacroAssembler* masm) {
 }
 
 
+void Builtins::Generate_StringConstructCode(MacroAssembler* masm) {
+  // TODO(849): implement custom construct stub.
+  // Generate a copy of the generic stub for now.
+  Generate_JSConstructStubGeneric(masm);
+}
+
+
 void Builtins::Generate_JSConstructCall(MacroAssembler* masm) {
   // ----------- S t a t e -------------
   //  -- rax: number of arguments