OLD | NEW |
1 // Copyright 2012 the V8 project authors. All rights reserved. | 1 // Copyright 2012 the V8 project authors. All rights reserved. |
2 // Use of this source code is governed by a BSD-style license that can be | 2 // Use of this source code is governed by a BSD-style license that can be |
3 // found in the LICENSE file. | 3 // found in the LICENSE file. |
4 | 4 |
5 #ifndef V8_OBJECTS_H_ | 5 #ifndef V8_OBJECTS_H_ |
6 #define V8_OBJECTS_H_ | 6 #define V8_OBJECTS_H_ |
7 | 7 |
8 #include "allocation.h" | 8 #include "allocation.h" |
9 #include "assert-scope.h" | 9 #include "assert-scope.h" |
10 #include "builtins.h" | 10 #include "builtins.h" |
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5994 kDescriptorIndexBitCount, kDescriptorIndexBitCount> {}; // NOLINT | 5994 kDescriptorIndexBitCount, kDescriptorIndexBitCount> {}; // NOLINT |
5995 STATIC_ASSERT(kDescriptorIndexBitCount + kDescriptorIndexBitCount == 20); | 5995 STATIC_ASSERT(kDescriptorIndexBitCount + kDescriptorIndexBitCount == 20); |
5996 class IsShared: public BitField<bool, 20, 1> {}; | 5996 class IsShared: public BitField<bool, 20, 1> {}; |
5997 class DictionaryMap: public BitField<bool, 21, 1> {}; | 5997 class DictionaryMap: public BitField<bool, 21, 1> {}; |
5998 class OwnsDescriptors: public BitField<bool, 22, 1> {}; | 5998 class OwnsDescriptors: public BitField<bool, 22, 1> {}; |
5999 class HasInstanceCallHandler: public BitField<bool, 23, 1> {}; | 5999 class HasInstanceCallHandler: public BitField<bool, 23, 1> {}; |
6000 class Deprecated: public BitField<bool, 24, 1> {}; | 6000 class Deprecated: public BitField<bool, 24, 1> {}; |
6001 class IsFrozen: public BitField<bool, 25, 1> {}; | 6001 class IsFrozen: public BitField<bool, 25, 1> {}; |
6002 class IsUnstable: public BitField<bool, 26, 1> {}; | 6002 class IsUnstable: public BitField<bool, 26, 1> {}; |
6003 class IsMigrationTarget: public BitField<bool, 27, 1> {}; | 6003 class IsMigrationTarget: public BitField<bool, 27, 1> {}; |
| 6004 class DoneInobjectSlackTracking: public BitField<bool, 28, 1> {}; |
| 6005 // Keep this bit field at the very end for better code in |
| 6006 // Builtins::kJSConstructStubGeneric stub. |
| 6007 class ConstructionCount: public BitField<int, 29, 3> {}; |
6004 | 6008 |
6005 // Tells whether the object in the prototype property will be used | 6009 // Tells whether the object in the prototype property will be used |
6006 // for instances created from this function. If the prototype | 6010 // for instances created from this function. If the prototype |
6007 // property is set to a value that is not a JSObject, the prototype | 6011 // property is set to a value that is not a JSObject, the prototype |
6008 // property will not be used to create instances of the function. | 6012 // property will not be used to create instances of the function. |
6009 // See ECMA-262, 13.2.2. | 6013 // See ECMA-262, 13.2.2. |
6010 inline void set_non_instance_prototype(bool value); | 6014 inline void set_non_instance_prototype(bool value); |
6011 inline bool has_non_instance_prototype(); | 6015 inline bool has_non_instance_prototype(); |
6012 | 6016 |
6013 // Tells whether function has special prototype property. If not, prototype | 6017 // Tells whether function has special prototype property. If not, prototype |
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6175 StoreMode store_mode, | 6179 StoreMode store_mode, |
6176 PropertyAttributes attributes, | 6180 PropertyAttributes attributes, |
6177 const char* reason); | 6181 const char* reason); |
6178 | 6182 |
6179 static Handle<Map> Normalize(Handle<Map> map, PropertyNormalizationMode mode); | 6183 static Handle<Map> Normalize(Handle<Map> map, PropertyNormalizationMode mode); |
6180 | 6184 |
6181 // Returns the constructor name (the name (possibly, inferred name) of the | 6185 // Returns the constructor name (the name (possibly, inferred name) of the |
6182 // function that was used to instantiate the object). | 6186 // function that was used to instantiate the object). |
6183 String* constructor_name(); | 6187 String* constructor_name(); |
6184 | 6188 |
6185 // Tells whether the map is attached to SharedFunctionInfo | |
6186 // (for inobject slack tracking). | |
6187 inline void set_attached_to_shared_function_info(bool value); | |
6188 | |
6189 inline bool attached_to_shared_function_info(); | |
6190 | |
6191 // Tells whether the map is shared between objects that may have different | 6189 // Tells whether the map is shared between objects that may have different |
6192 // behavior. If true, the map should never be modified, instead a clone | 6190 // behavior. If true, the map should never be modified, instead a clone |
6193 // should be created and modified. | 6191 // should be created and modified. |
6194 inline void set_is_shared(bool value); | 6192 inline void set_is_shared(bool value); |
6195 inline bool is_shared(); | 6193 inline bool is_shared(); |
6196 | 6194 |
6197 // Tells whether the map is used for JSObjects in dictionary mode (ie | 6195 // Tells whether the map is used for JSObjects in dictionary mode (ie |
6198 // normalized objects, ie objects for which HasFastProperties returns false). | 6196 // normalized objects, ie objects for which HasFastProperties returns false). |
6199 // A map can never be used for both dictionary mode and fast mode JSObjects. | 6197 // A map can never be used for both dictionary mode and fast mode JSObjects. |
6200 // False by default and for HeapObjects that are not JSObjects. | 6198 // False by default and for HeapObjects that are not JSObjects. |
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6315 inline bool owns_descriptors(); | 6313 inline bool owns_descriptors(); |
6316 inline void set_owns_descriptors(bool is_shared); | 6314 inline void set_owns_descriptors(bool is_shared); |
6317 inline bool has_instance_call_handler(); | 6315 inline bool has_instance_call_handler(); |
6318 inline void set_has_instance_call_handler(); | 6316 inline void set_has_instance_call_handler(); |
6319 inline void freeze(); | 6317 inline void freeze(); |
6320 inline bool is_frozen(); | 6318 inline bool is_frozen(); |
6321 inline void mark_unstable(); | 6319 inline void mark_unstable(); |
6322 inline bool is_stable(); | 6320 inline bool is_stable(); |
6323 inline void set_migration_target(bool value); | 6321 inline void set_migration_target(bool value); |
6324 inline bool is_migration_target(); | 6322 inline bool is_migration_target(); |
| 6323 inline void set_done_inobject_slack_tracking(bool value); |
| 6324 inline bool done_inobject_slack_tracking(); |
| 6325 inline void set_construction_count(int value); |
| 6326 inline int construction_count(); |
6325 inline void deprecate(); | 6327 inline void deprecate(); |
6326 inline bool is_deprecated(); | 6328 inline bool is_deprecated(); |
6327 inline bool CanBeDeprecated(); | 6329 inline bool CanBeDeprecated(); |
6328 // Returns a non-deprecated version of the input. If the input was not | 6330 // Returns a non-deprecated version of the input. If the input was not |
6329 // deprecated, it is directly returned. Otherwise, the non-deprecated version | 6331 // deprecated, it is directly returned. Otherwise, the non-deprecated version |
6330 // is found by re-transitioning from the root of the transition tree using the | 6332 // is found by re-transitioning from the root of the transition tree using the |
6331 // descriptor array of the map. Returns NULL if no updated map is found. | 6333 // descriptor array of the map. Returns NULL if no updated map is found. |
6332 // This method also applies any pending migrations along the prototype chain. | 6334 // This method also applies any pending migrations along the prototype chain. |
6333 static MaybeHandle<Map> CurrentMapForDeprecated(Handle<Map> map) | 6335 static MaybeHandle<Map> CurrentMapForDeprecated(Handle<Map> map) |
6334 V8_WARN_UNUSED_RESULT; | 6336 V8_WARN_UNUSED_RESULT; |
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6555 static const int kHasNamedInterceptor = 2; | 6557 static const int kHasNamedInterceptor = 2; |
6556 static const int kHasIndexedInterceptor = 3; | 6558 static const int kHasIndexedInterceptor = 3; |
6557 static const int kIsUndetectable = 4; | 6559 static const int kIsUndetectable = 4; |
6558 static const int kIsObserved = 5; | 6560 static const int kIsObserved = 5; |
6559 static const int kIsAccessCheckNeeded = 6; | 6561 static const int kIsAccessCheckNeeded = 6; |
6560 class FunctionWithPrototype: public BitField<bool, 7, 1> {}; | 6562 class FunctionWithPrototype: public BitField<bool, 7, 1> {}; |
6561 | 6563 |
6562 // Bit positions for bit field 2 | 6564 // Bit positions for bit field 2 |
6563 static const int kIsExtensible = 0; | 6565 static const int kIsExtensible = 0; |
6564 static const int kStringWrapperSafeForDefaultValueOf = 1; | 6566 static const int kStringWrapperSafeForDefaultValueOf = 1; |
6565 static const int kAttachedToSharedFunctionInfo = 2; | 6567 // Currently bit 2 is not used. |
6566 // No bits can be used after kElementsKindFirstBit, they are all reserved for | 6568 // No bits can be used after kElementsKindFirstBit, they are all reserved for |
6567 // storing ElementKind. | 6569 // storing ElementKind. |
6568 static const int kElementsKindShift = 3; | 6570 static const int kElementsKindShift = 3; |
6569 static const int kElementsKindBitCount = 5; | 6571 static const int kElementsKindBitCount = 5; |
6570 | 6572 |
6571 // Derived values from bit field 2 | 6573 // Derived values from bit field 2 |
6572 static const int kElementsKindMask = (-1 << kElementsKindShift) & | 6574 static const int kElementsKindMask = (-1 << kElementsKindShift) & |
6573 ((1 << (kElementsKindShift + kElementsKindBitCount)) - 1); | 6575 ((1 << (kElementsKindShift + kElementsKindBitCount)) - 1); |
6574 static const int8_t kMaximumBitField2FastElementValue = static_cast<int8_t>( | 6576 static const int8_t kMaximumBitField2FastElementValue = static_cast<int8_t>( |
6575 (FAST_ELEMENTS + 1) << Map::kElementsKindShift) - 1; | 6577 (FAST_ELEMENTS + 1) << Map::kElementsKindShift) - 1; |
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6948 inline void set_formal_parameter_count(int value); | 6950 inline void set_formal_parameter_count(int value); |
6949 | 6951 |
6950 // Set the formal parameter count so the function code will be | 6952 // Set the formal parameter count so the function code will be |
6951 // called without using argument adaptor frames. | 6953 // called without using argument adaptor frames. |
6952 inline void DontAdaptArguments(); | 6954 inline void DontAdaptArguments(); |
6953 | 6955 |
6954 // [expected_nof_properties]: Expected number of properties for the function. | 6956 // [expected_nof_properties]: Expected number of properties for the function. |
6955 inline int expected_nof_properties(); | 6957 inline int expected_nof_properties(); |
6956 inline void set_expected_nof_properties(int value); | 6958 inline void set_expected_nof_properties(int value); |
6957 | 6959 |
6958 // Inobject slack tracking is the way to reclaim unused inobject space. | |
6959 // | |
6960 // The instance size is initially determined by adding some slack to | |
6961 // expected_nof_properties (to allow for a few extra properties added | |
6962 // after the constructor). There is no guarantee that the extra space | |
6963 // will not be wasted. | |
6964 // | |
6965 // Here is the algorithm to reclaim the unused inobject space: | |
6966 // - Detect the first constructor call for this SharedFunctionInfo. | |
6967 // When it happens enter the "in progress" state: remember the | |
6968 // constructor's initial_map and install a special construct stub that | |
6969 // counts constructor calls. | |
6970 // - While the tracking is in progress create objects filled with | |
6971 // one_pointer_filler_map instead of undefined_value. This way they can be | |
6972 // resized quickly and safely. | |
6973 // - Once enough (kGenerousAllocationCount) objects have been created | |
6974 // compute the 'slack' (traverse the map transition tree starting from the | |
6975 // initial_map and find the lowest value of unused_property_fields). | |
6976 // - Traverse the transition tree again and decrease the instance size | |
6977 // of every map. Existing objects will resize automatically (they are | |
6978 // filled with one_pointer_filler_map). All further allocations will | |
6979 // use the adjusted instance size. | |
6980 // - Decrease expected_nof_properties so that an allocations made from | |
6981 // another context will use the adjusted instance size too. | |
6982 // - Exit "in progress" state by clearing the reference to the initial_map | |
6983 // and setting the regular construct stub (generic or inline). | |
6984 // | |
6985 // The above is the main event sequence. Some special cases are possible | |
6986 // while the tracking is in progress: | |
6987 // | |
6988 // - GC occurs. | |
6989 // Check if the initial_map is referenced by any live objects (except this | |
6990 // SharedFunctionInfo). If it is, continue tracking as usual. | |
6991 // If it is not, clear the reference and reset the tracking state. The | |
6992 // tracking will be initiated again on the next constructor call. | |
6993 // | |
6994 // - The constructor is called from another context. | |
6995 // Immediately complete the tracking, perform all the necessary changes | |
6996 // to maps. This is necessary because there is no efficient way to track | |
6997 // multiple initial_maps. | |
6998 // Proceed to create an object in the current context (with the adjusted | |
6999 // size). | |
7000 // | |
7001 // - A different constructor function sharing the same SharedFunctionInfo is | |
7002 // called in the same context. This could be another closure in the same | |
7003 // context, or the first function could have been disposed. | |
7004 // This is handled the same way as the previous case. | |
7005 // | |
7006 // Important: inobject slack tracking is not attempted during the snapshot | |
7007 // creation. | |
7008 | |
7009 static const int kGenerousAllocationCount = 8; | |
7010 | |
7011 // [construction_count]: Counter for constructor calls made during | |
7012 // the tracking phase. | |
7013 inline int construction_count(); | |
7014 inline void set_construction_count(int value); | |
7015 | |
7016 // [feedback_vector] - accumulates ast node feedback from full-codegen and | 6960 // [feedback_vector] - accumulates ast node feedback from full-codegen and |
7017 // (increasingly) from crankshafted code where sufficient feedback isn't | 6961 // (increasingly) from crankshafted code where sufficient feedback isn't |
7018 // available. Currently the field is duplicated in | 6962 // available. Currently the field is duplicated in |
7019 // TypeFeedbackInfo::feedback_vector, but the allocation is done here. | 6963 // TypeFeedbackInfo::feedback_vector, but the allocation is done here. |
7020 DECL_ACCESSORS(feedback_vector, FixedArray) | 6964 DECL_ACCESSORS(feedback_vector, FixedArray) |
7021 | 6965 |
7022 // [initial_map]: initial map of the first function called as a constructor. | |
7023 // Saved for the duration of the tracking phase. | |
7024 // This is a weak link (GC resets it to undefined_value if no other live | |
7025 // object reference this map). | |
7026 DECL_ACCESSORS(initial_map, Object) | |
7027 | |
7028 // True if the initial_map is not undefined and the countdown stub is | |
7029 // installed. | |
7030 inline bool IsInobjectSlackTrackingInProgress(); | |
7031 | |
7032 // Starts the tracking. | |
7033 // Stores the initial map and installs the countdown stub. | |
7034 // IsInobjectSlackTrackingInProgress is normally true after this call, | |
7035 // except when tracking have not been started (e.g. the map has no unused | |
7036 // properties or the snapshot is being built). | |
7037 void StartInobjectSlackTracking(Map* map); | |
7038 | |
7039 // Completes the tracking. | |
7040 // IsInobjectSlackTrackingInProgress is false after this call. | |
7041 void CompleteInobjectSlackTracking(); | |
7042 | |
7043 // Invoked before pointers in SharedFunctionInfo are being marked. | 6966 // Invoked before pointers in SharedFunctionInfo are being marked. |
7044 // Also clears the optimized code map. | 6967 // Also clears the optimized code map. |
7045 inline void BeforeVisitingPointers(); | 6968 inline void BeforeVisitingPointers(); |
7046 | 6969 |
7047 // Clears the initial_map before the GC marking phase to ensure the reference | |
7048 // is weak. IsInobjectSlackTrackingInProgress is false after this call. | |
7049 void DetachInitialMap(); | |
7050 | |
7051 // Restores the link to the initial map after the GC marking phase. | |
7052 // IsInobjectSlackTrackingInProgress is true after this call. | |
7053 void AttachInitialMap(Map* map); | |
7054 | |
7055 // False if there are definitely no live objects created from this function. | |
7056 // True if live objects _may_ exist (existence not guaranteed). | |
7057 // May go back from true to false after GC. | |
7058 DECL_BOOLEAN_ACCESSORS(live_objects_may_exist) | |
7059 | |
7060 // [instance class name]: class name for instances. | 6970 // [instance class name]: class name for instances. |
7061 DECL_ACCESSORS(instance_class_name, Object) | 6971 DECL_ACCESSORS(instance_class_name, Object) |
7062 | 6972 |
7063 // [function data]: This field holds some additional data for function. | 6973 // [function data]: This field holds some additional data for function. |
7064 // Currently it either has FunctionTemplateInfo to make benefit the API | 6974 // Currently it either has FunctionTemplateInfo to make benefit the API |
7065 // or Smi identifying a builtin function. | 6975 // or Smi identifying a builtin function. |
7066 // In the long run we don't want all functions to have this field but | 6976 // In the long run we don't want all functions to have this field but |
7067 // we can fix that when we have a better model for storing hidden data | 6977 // we can fix that when we have a better model for storing hidden data |
7068 // on objects. | 6978 // on objects. |
7069 DECL_ACCESSORS(function_data, Object) | 6979 DECL_ACCESSORS(function_data, Object) |
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7295 static const int kConstructStubOffset = kScopeInfoOffset + kPointerSize; | 7205 static const int kConstructStubOffset = kScopeInfoOffset + kPointerSize; |
7296 static const int kInstanceClassNameOffset = | 7206 static const int kInstanceClassNameOffset = |
7297 kConstructStubOffset + kPointerSize; | 7207 kConstructStubOffset + kPointerSize; |
7298 static const int kFunctionDataOffset = | 7208 static const int kFunctionDataOffset = |
7299 kInstanceClassNameOffset + kPointerSize; | 7209 kInstanceClassNameOffset + kPointerSize; |
7300 static const int kScriptOffset = kFunctionDataOffset + kPointerSize; | 7210 static const int kScriptOffset = kFunctionDataOffset + kPointerSize; |
7301 static const int kDebugInfoOffset = kScriptOffset + kPointerSize; | 7211 static const int kDebugInfoOffset = kScriptOffset + kPointerSize; |
7302 static const int kInferredNameOffset = kDebugInfoOffset + kPointerSize; | 7212 static const int kInferredNameOffset = kDebugInfoOffset + kPointerSize; |
7303 static const int kFeedbackVectorOffset = | 7213 static const int kFeedbackVectorOffset = |
7304 kInferredNameOffset + kPointerSize; | 7214 kInferredNameOffset + kPointerSize; |
7305 static const int kInitialMapOffset = | |
7306 kFeedbackVectorOffset + kPointerSize; | |
7307 #if V8_HOST_ARCH_32_BIT | 7215 #if V8_HOST_ARCH_32_BIT |
7308 // Smi fields. | 7216 // Smi fields. |
7309 static const int kLengthOffset = | 7217 static const int kLengthOffset = |
7310 kInitialMapOffset + kPointerSize; | 7218 kFeedbackVectorOffset + kPointerSize; |
7311 static const int kFormalParameterCountOffset = kLengthOffset + kPointerSize; | 7219 static const int kFormalParameterCountOffset = kLengthOffset + kPointerSize; |
7312 static const int kExpectedNofPropertiesOffset = | 7220 static const int kExpectedNofPropertiesOffset = |
7313 kFormalParameterCountOffset + kPointerSize; | 7221 kFormalParameterCountOffset + kPointerSize; |
7314 static const int kNumLiteralsOffset = | 7222 static const int kNumLiteralsOffset = |
7315 kExpectedNofPropertiesOffset + kPointerSize; | 7223 kExpectedNofPropertiesOffset + kPointerSize; |
7316 static const int kStartPositionAndTypeOffset = | 7224 static const int kStartPositionAndTypeOffset = |
7317 kNumLiteralsOffset + kPointerSize; | 7225 kNumLiteralsOffset + kPointerSize; |
7318 static const int kEndPositionOffset = | 7226 static const int kEndPositionOffset = |
7319 kStartPositionAndTypeOffset + kPointerSize; | 7227 kStartPositionAndTypeOffset + kPointerSize; |
7320 static const int kFunctionTokenPositionOffset = | 7228 static const int kFunctionTokenPositionOffset = |
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7336 // The only reason to use smi fields instead of int fields | 7244 // The only reason to use smi fields instead of int fields |
7337 // is to allow iteration without maps decoding during | 7245 // is to allow iteration without maps decoding during |
7338 // garbage collections. | 7246 // garbage collections. |
7339 // To avoid wasting space on 64-bit architectures we use | 7247 // To avoid wasting space on 64-bit architectures we use |
7340 // the following trick: we group integer fields into pairs | 7248 // the following trick: we group integer fields into pairs |
7341 // First integer in each pair is shifted left by 1. | 7249 // First integer in each pair is shifted left by 1. |
7342 // By doing this we guarantee that LSB of each kPointerSize aligned | 7250 // By doing this we guarantee that LSB of each kPointerSize aligned |
7343 // word is not set and thus this word cannot be treated as pointer | 7251 // word is not set and thus this word cannot be treated as pointer |
7344 // to HeapObject during old space traversal. | 7252 // to HeapObject during old space traversal. |
7345 static const int kLengthOffset = | 7253 static const int kLengthOffset = |
7346 kInitialMapOffset + kPointerSize; | 7254 kFeedbackVectorOffset + kPointerSize; |
7347 static const int kFormalParameterCountOffset = | 7255 static const int kFormalParameterCountOffset = |
7348 kLengthOffset + kIntSize; | 7256 kLengthOffset + kIntSize; |
7349 | 7257 |
7350 static const int kExpectedNofPropertiesOffset = | 7258 static const int kExpectedNofPropertiesOffset = |
7351 kFormalParameterCountOffset + kIntSize; | 7259 kFormalParameterCountOffset + kIntSize; |
7352 static const int kNumLiteralsOffset = | 7260 static const int kNumLiteralsOffset = |
7353 kExpectedNofPropertiesOffset + kIntSize; | 7261 kExpectedNofPropertiesOffset + kIntSize; |
7354 | 7262 |
7355 static const int kEndPositionOffset = | 7263 static const int kEndPositionOffset = |
7356 kNumLiteralsOffset + kIntSize; | 7264 kNumLiteralsOffset + kIntSize; |
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7370 static const int kAstNodeCountOffset = | 7278 static const int kAstNodeCountOffset = |
7371 kCountersOffset + kIntSize; | 7279 kCountersOffset + kIntSize; |
7372 static const int kProfilerTicksOffset = | 7280 static const int kProfilerTicksOffset = |
7373 kAstNodeCountOffset + kIntSize; | 7281 kAstNodeCountOffset + kIntSize; |
7374 | 7282 |
7375 // Total size. | 7283 // Total size. |
7376 static const int kSize = kProfilerTicksOffset + kIntSize; | 7284 static const int kSize = kProfilerTicksOffset + kIntSize; |
7377 | 7285 |
7378 #endif | 7286 #endif |
7379 | 7287 |
7380 // The construction counter for inobject slack tracking is stored in the | |
7381 // most significant byte of compiler_hints which is otherwise unused. | |
7382 // Its offset depends on the endian-ness of the architecture. | |
7383 #if defined(V8_TARGET_LITTLE_ENDIAN) | |
7384 static const int kConstructionCountOffset = kCompilerHintsOffset + 3; | |
7385 #elif defined(V8_TARGET_BIG_ENDIAN) | |
7386 static const int kConstructionCountOffset = kCompilerHintsOffset + 0; | |
7387 #else | |
7388 #error Unknown byte ordering | |
7389 #endif | |
7390 | |
7391 static const int kAlignedSize = POINTER_SIZE_ALIGN(kSize); | 7288 static const int kAlignedSize = POINTER_SIZE_ALIGN(kSize); |
7392 | 7289 |
7393 typedef FixedBodyDescriptor<kNameOffset, | 7290 typedef FixedBodyDescriptor<kNameOffset, |
7394 kInitialMapOffset + kPointerSize, | 7291 kFeedbackVectorOffset + kPointerSize, |
7395 kSize> BodyDescriptor; | 7292 kSize> BodyDescriptor; |
7396 | 7293 |
7397 // Bit positions in start_position_and_type. | 7294 // Bit positions in start_position_and_type. |
7398 // The source code start position is in the 30 most significant bits of | 7295 // The source code start position is in the 30 most significant bits of |
7399 // the start_position_and_type field. | 7296 // the start_position_and_type field. |
7400 static const int kIsExpressionBit = 0; | 7297 static const int kIsExpressionBit = 0; |
7401 static const int kIsTopLevelBit = 1; | 7298 static const int kIsTopLevelBit = 1; |
7402 static const int kStartPositionShift = 2; | 7299 static const int kStartPositionShift = 2; |
7403 static const int kStartPositionMask = ~((1 << kStartPositionShift) - 1); | 7300 static const int kStartPositionMask = ~((1 << kStartPositionShift) - 1); |
7404 | 7301 |
7405 // Bit positions in compiler_hints. | 7302 // Bit positions in compiler_hints. |
7406 enum CompilerHints { | 7303 enum CompilerHints { |
7407 kAllowLazyCompilation, | 7304 kAllowLazyCompilation, |
7408 kAllowLazyCompilationWithoutContext, | 7305 kAllowLazyCompilationWithoutContext, |
7409 kLiveObjectsMayExist, | |
7410 kOptimizationDisabled, | 7306 kOptimizationDisabled, |
7411 kStrictModeFunction, | 7307 kStrictModeFunction, |
7412 kUsesArguments, | 7308 kUsesArguments, |
7413 kHasDuplicateParameters, | 7309 kHasDuplicateParameters, |
7414 kNative, | 7310 kNative, |
7415 kInlineBuiltin, | 7311 kInlineBuiltin, |
7416 kBoundFunction, | 7312 kBoundFunction, |
7417 kIsAnonymous, | 7313 kIsAnonymous, |
7418 kNameShouldPrintAsAnonymous, | 7314 kNameShouldPrintAsAnonymous, |
7419 kIsFunction, | 7315 kIsFunction, |
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7615 void MarkInOptimizationQueue(); | 7511 void MarkInOptimizationQueue(); |
7616 | 7512 |
7617 // Tells whether or not the function is already marked for lazy | 7513 // Tells whether or not the function is already marked for lazy |
7618 // recompilation. | 7514 // recompilation. |
7619 inline bool IsMarkedForOptimization(); | 7515 inline bool IsMarkedForOptimization(); |
7620 inline bool IsMarkedForConcurrentOptimization(); | 7516 inline bool IsMarkedForConcurrentOptimization(); |
7621 | 7517 |
7622 // Tells whether or not the function is on the concurrent recompilation queue. | 7518 // Tells whether or not the function is on the concurrent recompilation queue. |
7623 inline bool IsInOptimizationQueue(); | 7519 inline bool IsInOptimizationQueue(); |
7624 | 7520 |
| 7521 // Inobject slack tracking is the way to reclaim unused inobject space. |
| 7522 // |
| 7523 // The instance size is initially determined by adding some slack to |
| 7524 // expected_nof_properties (to allow for a few extra properties added |
| 7525 // after the constructor). There is no guarantee that the extra space |
| 7526 // will not be wasted. |
| 7527 // |
| 7528 // Here is the algorithm to reclaim the unused inobject space: |
| 7529 // - Detect the first constructor call for this JSFunction. |
| 7530 // When it happens enter the "in progress" state: initialize construction |
| 7531 // counter in the initial_map and set the |done_inobject_slack_tracking| |
| 7532 // flag. |
| 7533 // - While the tracking is in progress create objects filled with |
| 7534 // one_pointer_filler_map instead of undefined_value. This way they can be |
| 7535 // resized quickly and safely. |
| 7536 // - Once enough (kGenerousAllocationCount) objects have been created |
| 7537 // compute the 'slack' (traverse the map transition tree starting from the |
| 7538 // initial_map and find the lowest value of unused_property_fields). |
| 7539 // - Traverse the transition tree again and decrease the instance size |
| 7540 // of every map. Existing objects will resize automatically (they are |
| 7541 // filled with one_pointer_filler_map). All further allocations will |
| 7542 // use the adjusted instance size. |
| 7543 // - SharedFunctionInfo's expected_nof_properties left unmodified since |
| 7544 // allocations made using different closures could actually create different |
| 7545 // kind of objects (see prototype inheritance pattern). |
| 7546 // |
| 7547 // Important: inobject slack tracking is not attempted during the snapshot |
| 7548 // creation. |
| 7549 |
| 7550 static const int kGenerousAllocationCount = Map::ConstructionCount::kMax; |
| 7551 static const int kFinishSlackTracking = 1; |
| 7552 static const int kNoSlackTracking = 0; |
| 7553 |
| 7554 // True if the initial_map is set and the object constructions countdown |
| 7555 // counter is not zero. |
| 7556 inline bool IsInobjectSlackTrackingInProgress(); |
| 7557 |
| 7558 // Starts the tracking. |
| 7559 // Initializes object constructions countdown counter in the initial map. |
| 7560 // IsInobjectSlackTrackingInProgress is normally true after this call, |
| 7561 // except when tracking have not been started (e.g. the map has no unused |
| 7562 // properties or the snapshot is being built). |
| 7563 void StartInobjectSlackTracking(); |
| 7564 |
| 7565 // Completes the tracking. |
| 7566 // IsInobjectSlackTrackingInProgress is false after this call. |
| 7567 void CompleteInobjectSlackTracking(); |
| 7568 |
7625 // [literals_or_bindings]: Fixed array holding either | 7569 // [literals_or_bindings]: Fixed array holding either |
7626 // the materialized literals or the bindings of a bound function. | 7570 // the materialized literals or the bindings of a bound function. |
7627 // | 7571 // |
7628 // If the function contains object, regexp or array literals, the | 7572 // If the function contains object, regexp or array literals, the |
7629 // literals array prefix contains the object, regexp, and array | 7573 // literals array prefix contains the object, regexp, and array |
7630 // function to be used when creating these literals. This is | 7574 // function to be used when creating these literals. This is |
7631 // necessary so that we do not dynamically lookup the object, regexp | 7575 // necessary so that we do not dynamically lookup the object, regexp |
7632 // or array functions. Performing a dynamic lookup, we might end up | 7576 // or array functions. Performing a dynamic lookup, we might end up |
7633 // using the functions from a new context that we should not have | 7577 // using the functions from a new context that we should not have |
7634 // access to. | 7578 // access to. |
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11122 } else { | 11066 } else { |
11123 value &= ~(1 << bit_position); | 11067 value &= ~(1 << bit_position); |
11124 } | 11068 } |
11125 return value; | 11069 return value; |
11126 } | 11070 } |
11127 }; | 11071 }; |
11128 | 11072 |
11129 } } // namespace v8::internal | 11073 } } // namespace v8::internal |
11130 | 11074 |
11131 #endif // V8_OBJECTS_H_ | 11075 #endif // V8_OBJECTS_H_ |
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