Introduce intrinsic to expose debug state to generated code.

R=ulan@chromium.org

Review URL: https://codereview.chromium.org/332673002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@21908 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/arm/full-codegen-arm.cc

@@ -4009,6 +4009,17 @@ void FullCodeGenerator::EmitFastAsciiArrayJoin(CallRuntime* expr) {
 }
 
 
+void FullCodeGenerator::EmitDebugIsActive(CallRuntime* expr) {
+  ASSERT(expr->arguments()->length() == 0);
+  ExternalReference debug_is_active =
+      ExternalReference::debug_is_active_address(isolate());
+  __ mov(ip, Operand(debug_is_active));
+  __ ldrb(r0, MemOperand(ip));
+  __ SmiTag(r0);
+  context()->Plug(r0);
+}
+
+
 void FullCodeGenerator::VisitCallRuntime(CallRuntime* expr) {
   if (expr->function() != NULL &&
       expr->function()->intrinsic_type == Runtime::INLINE) {

src/arm64/full-codegen-arm64.cc

@@ -3720,6 +3720,17 @@ void FullCodeGenerator::EmitFastAsciiArrayJoin(CallRuntime* expr) {
 }
 
 
+void FullCodeGenerator::EmitDebugIsActive(CallRuntime* expr) {
+  ASSERT(expr->arguments()->length() == 0);
+  ExternalReference debug_is_active =
+      ExternalReference::debug_is_active_address(isolate());
+  __ Mov(x10, debug_is_active);
+  __ Ldrb(x0, MemOperand(x10));
+  __ SmiTag(x0);
+  context()->Plug(x0);
+}
+
+
 void FullCodeGenerator::VisitCallRuntime(CallRuntime* expr) {
   if (expr->function() != NULL &&
       expr->function()->intrinsic_type == Runtime::INLINE) {

src/array.js

@@ -1128,7 +1128,7 @@ function ArrayFilter(f, receiver) {
   var result = new $Array();
   var accumulator = new InternalArray();
   var accumulator_length = 0;
-  var stepping = %_DebugCallbackSupportsStepping(f);
+  var stepping = DEBUG_IS_ACTIVE && %DebugCallbackSupportsStepping(f);
   for (var i = 0; i < length; i++) {
     if (i in array) {
       var element = array[i];
@@ -1161,7 +1161,7 @@ function ArrayForEach(f, receiver) {
     receiver = ToObject(receiver);
   }
 
-  var stepping = %_DebugCallbackSupportsStepping(f);
+  var stepping = DEBUG_IS_ACTIVE && %DebugCallbackSupportsStepping(f);
   for (var i = 0; i < length; i++) {
     if (i in array) {
       var element = array[i];
@@ -1192,7 +1192,7 @@ function ArraySome(f, receiver) {
     receiver = ToObject(receiver);
   }
 
-  var stepping = %_DebugCallbackSupportsStepping(f);
+  var stepping = DEBUG_IS_ACTIVE && %DebugCallbackSupportsStepping(f);
   for (var i = 0; i < length; i++) {
     if (i in array) {
       var element = array[i];
@@ -1222,7 +1222,7 @@ function ArrayEvery(f, receiver) {
     receiver = ToObject(receiver);
   }
 
-  var stepping = %_DebugCallbackSupportsStepping(f);
+  var stepping = DEBUG_IS_ACTIVE && %DebugCallbackSupportsStepping(f);
   for (var i = 0; i < length; i++) {
     if (i in array) {
       var element = array[i];
@@ -1253,7 +1253,7 @@ function ArrayMap(f, receiver) {
 
   var result = new $Array();
   var accumulator = new InternalArray(length);
-  var stepping = %_DebugCallbackSupportsStepping(f);
+  var stepping = DEBUG_IS_ACTIVE && %DebugCallbackSupportsStepping(f);
   for (var i = 0; i < length; i++) {
     if (i in array) {
       var element = array[i];
@@ -1400,7 +1400,7 @@ function ArrayReduce(callback, current) {
   }
 
   var receiver = %GetDefaultReceiver(callback);
-  var stepping = %_DebugCallbackSupportsStepping(callback);
+  var stepping = DEBUG_IS_ACTIVE && %DebugCallbackSupportsStepping(callback);
   for (; i < length; i++) {
     if (i in array) {
       var element = array[i];
@@ -1437,7 +1437,7 @@ function ArrayReduceRight(callback, current) {
   }
 
   var receiver = %GetDefaultReceiver(callback);
-  var stepping = %_DebugCallbackSupportsStepping(callback);
+  var stepping = DEBUG_IS_ACTIVE && %DebugCallbackSupportsStepping(callback);
   for (; i >= 0; i--) {
     if (i in array) {
       var element = array[i];

src/assembler.cc

@@ -1428,6 +1428,12 @@ ExternalReference ExternalReference::cpu_features() {
 }
 
 
+ExternalReference ExternalReference::debug_is_active_address(
+    Isolate* isolate) {
+  return ExternalReference(isolate->debug()->is_active_address());
+}
+
+
 ExternalReference ExternalReference::debug_after_break_target_address(
     Isolate* isolate) {
   return ExternalReference(isolate->debug()->after_break_target_address());

src/assembler.h

@@ -911,6 +911,7 @@ class ExternalReference BASE_EMBEDDED {
 
   static ExternalReference cpu_features();
 
+  static ExternalReference debug_is_active_address(Isolate* isolate);
   static ExternalReference debug_after_break_target_address(Isolate* isolate);
   static ExternalReference debug_restarter_frame_function_pointer_address(
       Isolate* isolate);

src/collection.js

@@ -81,7 +81,7 @@ function SetForEach(f, receiver) {
 
   var iterator = new SetIterator(this, ITERATOR_KIND_VALUES);
   var entry;
-  var stepping = %_DebugCallbackSupportsStepping(f);
+  var stepping = DEBUG_IS_ACTIVE && %DebugCallbackSupportsStepping(f);
   while (!(entry = %SetIteratorNext(iterator)).done) {
     if (stepping) %DebugPrepareStepInIfStepping(f);
     %_CallFunction(receiver, entry.value, entry.value, this, f);
@@ -192,7 +192,7 @@ function MapForEach(f, receiver) {
 
   var iterator = new MapIterator(this, ITERATOR_KIND_ENTRIES);
   var entry;
-  var stepping = %_DebugCallbackSupportsStepping(f);
+  var stepping = DEBUG_IS_ACTIVE && %DebugCallbackSupportsStepping(f);
   while (!(entry = %MapIteratorNext(iterator)).done) {
     if (stepping) %DebugPrepareStepInIfStepping(f);
     %_CallFunction(receiver, entry.value[1], entry.value[0], this, f);

src/debug.h

@@ -505,6 +505,10 @@ class Debug {
   int break_id() { return thread_local_.break_id_; }
 
   // Support for embedding into generated code.
+  Address is_active_address() {
+    return reinterpret_cast<Address>(&is_active_);
+  }
+
   Address after_break_target_address() {
     return reinterpret_cast<Address>(&after_break_target_);
   }

src/hydrogen-instructions.h

@@ -6120,6 +6120,11 @@ class HObjectAccess V8_FINAL {
                          Handle<String>::null(), false, false);
   }
 
+  static HObjectAccess ForExternalUInteger8() {
+    return HObjectAccess(kExternalMemory, 0, Representation::UInteger8(),
+                         Handle<String>::null(), false, false);
+  }
+
   // Create an access to an offset in a fixed array header.
   static HObjectAccess ForFixedArrayHeader(int offset);
 

src/hydrogen.cc

@@ -11711,11 +11711,13 @@ void HOptimizedGraphBuilder::GenerateDebugBreakInOptimizedCode(
 }
 
 
-void HOptimizedGraphBuilder::GenerateDebugCallbackSupportsStepping(
-    CallRuntime* call) {
-  ASSERT(call->arguments()->length() == 1);
-  // Debugging is not supported in optimized code.
-  return ast_context()->ReturnValue(graph()->GetConstantFalse());
+void HOptimizedGraphBuilder::GenerateDebugIsActive(CallRuntime* call) {
+  ASSERT(call->arguments()->length() == 0);
+  HValue* ref =
+      Add<HConstant>(ExternalReference::debug_is_active_address(isolate()));
+  HValue* value = Add<HLoadNamedField>(
+      ref, static_cast<HValue*>(NULL), HObjectAccess::ForExternalUInteger8());
+  return ast_context()->ReturnValue(value);
 }
 
 

src/ia32/full-codegen-ia32.cc

@@ -3996,6 +3996,16 @@ void FullCodeGenerator::EmitFastAsciiArrayJoin(CallRuntime* expr) {
 }
 
 
+void FullCodeGenerator::EmitDebugIsActive(CallRuntime* expr) {
+  ASSERT(expr->arguments()->length() == 0);
+  ExternalReference debug_is_active =
+      ExternalReference::debug_is_active_address(isolate());
+  __ movzx_b(eax, Operand::StaticVariable(debug_is_active));
+  __ SmiTag(eax);
+  context()->Plug(eax);
+}
+
+
 void FullCodeGenerator::VisitCallRuntime(CallRuntime* expr) {
   if (expr->function() != NULL &&
       expr->function()->intrinsic_type == Runtime::INLINE) {

src/macros.py

@@ -285,3 +285,6 @@ const PROPERTY_ATTRIBUTES_PRIVATE_SYMBOL = 32;
 const ITERATOR_KIND_KEYS = 1;
 const ITERATOR_KIND_VALUES = 2;
 const ITERATOR_KIND_ENTRIES = 3;
+
+# Check whether debug is active.
+const DEBUG_IS_ACTIVE = (%_DebugIsActive() != 0);

src/runtime.h

@@ -438,6 +438,7 @@ namespace internal {
   F(DebugConstructedBy, 2, 1) \
   F(DebugGetPrototype, 1, 1) \
   F(DebugSetScriptSource, 2, 1) \
+  F(DebugCallbackSupportsStepping, 1, 1) \
   F(SystemBreak, 0, 1) \
   F(DebugDisassembleFunction, 1, 1) \
   F(DebugDisassembleConstructor, 1, 1) \
@@ -654,7 +655,8 @@ namespace internal {
   F(RegExpExec, 4, 1)                                                        \
   F(RegExpConstructResult, 3, 1)                                             \
   F(GetFromCache, 2, 1)                                                      \
-  F(NumberToString, 1, 1)
+  F(NumberToString, 1, 1)                                                    \
+  F(DebugIsActive, 0, 1)
 
 
 // ----------------------------------------------------------------------------
@@ -680,9 +682,7 @@ namespace internal {
   F(DoubleHi, 1, 1)                                                          \
   F(DoubleLo, 1, 1)                                                          \
   F(MathSqrtRT, 1, 1)                                                        \
-  F(MathLogRT, 1, 1)                                                         \
-  /* Debugger */                                                             \
-  F(DebugCallbackSupportsStepping, 1, 1)
+  F(MathLogRT, 1, 1)
 
 
 //---------------------------------------------------------------------------

src/x64/full-codegen-x64.cc

@@ -4004,6 +4004,17 @@ void FullCodeGenerator::EmitFastAsciiArrayJoin(CallRuntime* expr) {
 }
 
 
+void FullCodeGenerator::EmitDebugIsActive(CallRuntime* expr) {
+  ASSERT(expr->arguments()->length() == 0);
+  ExternalReference debug_is_active =
+      ExternalReference::debug_is_active_address(isolate());
+  __ Move(kScratchRegister, debug_is_active);
+  __ movzxbp(rax, Operand(kScratchRegister, 0));
+  __ Integer32ToSmi(rax, rax);
+  context()->Plug(rax);
+}
+
+
 void FullCodeGenerator::VisitCallRuntime(CallRuntime* expr) {
   if (expr->function() != NULL &&
       expr->function()->intrinsic_type == Runtime::INLINE) {

test/mjsunit/debug-is-active.js

+// Copyright 2014 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Flags: --expose-debug-as debug --allow-natives-syntax
+
+Debug = debug.Debug;
+
+function f() { return %_DebugIsActive() != 0; }
+
+assertFalse(f());
+assertFalse(f());
+Debug.setListener(function() {});
+assertTrue(f());
+Debug.setListener(null);
+assertFalse(f());
+
+%OptimizeFunctionOnNextCall(f);
+assertFalse(f());
+assertOptimized(f);
+
+Debug.setListener(function() {});
+assertTrue(f());
+assertOptimized(f);
+
+Debug.setListener(null);
+assertFalse(f());
+assertOptimized(f);