1 // Copyright 2012 the V8 project authors. All rights reserved.
2 // Redistribution and use in source and binary forms, with or without
3 // modification, are permitted provided that the following conditions are
6 // * Redistributions of source code must retain the above copyright
7 // notice, this list of conditions and the following disclaimer.
8 // * Redistributions in binary form must reproduce the above
9 // copyright notice, this list of conditions and the following
10 // disclaimer in the documentation and/or other materials provided
11 // with the distribution.
12 // * Neither the name of Google Inc. nor the names of its
13 // contributors may be used to endorse or promote products derived
14 // from this software without specific prior written permission.
16 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
17 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
18 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
19 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
20 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
21 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
22 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
26 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28 #ifndef V8_V8GLOBALS_H_
29 #define V8_V8GLOBALS_H_
37 // This file contains constants and global declarations related to the
40 // Mask for the sign bit in a smi.
41 const intptr_t kSmiSignMask = kIntptrSignBit;
43 const int kObjectAlignmentBits = kPointerSizeLog2;
44 const intptr_t kObjectAlignment = 1 << kObjectAlignmentBits;
45 const intptr_t kObjectAlignmentMask = kObjectAlignment - 1;
47 // Desired alignment for pointers.
48 const intptr_t kPointerAlignment = (1 << kPointerSizeLog2);
49 const intptr_t kPointerAlignmentMask = kPointerAlignment - 1;
51 // Desired alignment for double values.
52 const intptr_t kDoubleAlignment = 8;
53 const intptr_t kDoubleAlignmentMask = kDoubleAlignment - 1;
55 // Desired alignment for maps.
56 #if V8_HOST_ARCH_64_BIT
57 const intptr_t kMapAlignmentBits = kObjectAlignmentBits;
59 const intptr_t kMapAlignmentBits = kObjectAlignmentBits + 3;
61 const intptr_t kMapAlignment = (1 << kMapAlignmentBits);
62 const intptr_t kMapAlignmentMask = kMapAlignment - 1;
64 // Desired alignment for generated code is 32 bytes (to improve cache line
66 const int kCodeAlignmentBits = 5;
67 const intptr_t kCodeAlignment = 1 << kCodeAlignmentBits;
68 const intptr_t kCodeAlignmentMask = kCodeAlignment - 1;
70 // Tag information for Failure.
71 const int kFailureTag = 3;
72 const int kFailureTagSize = 2;
73 const intptr_t kFailureTagMask = (1 << kFailureTagSize) - 1;
76 // Zap-value: The value used for zapping dead objects.
77 // Should be a recognizable hex value tagged as a failure.
78 #ifdef V8_HOST_ARCH_64_BIT
79 const Address kZapValue =
80 reinterpret_cast<Address>(V8_UINT64_C(0xdeadbeedbeadbeef));
81 const Address kHandleZapValue =
82 reinterpret_cast<Address>(V8_UINT64_C(0x1baddead0baddeaf));
83 const Address kFromSpaceZapValue =
84 reinterpret_cast<Address>(V8_UINT64_C(0x1beefdad0beefdaf));
85 const uint64_t kDebugZapValue = V8_UINT64_C(0xbadbaddbbadbaddb);
86 const uint64_t kSlotsZapValue = V8_UINT64_C(0xbeefdeadbeefdeef);
87 const uint64_t kFreeListZapValue = 0xfeed1eaffeed1eaf;
89 const Address kZapValue = reinterpret_cast<Address>(0xdeadbeef);
90 const Address kHandleZapValue = reinterpret_cast<Address>(0xbaddeaf);
91 const Address kFromSpaceZapValue = reinterpret_cast<Address>(0xbeefdaf);
92 const uint32_t kSlotsZapValue = 0xbeefdeef;
93 const uint32_t kDebugZapValue = 0xbadbaddb;
94 const uint32_t kFreeListZapValue = 0xfeed1eaf;
98 // Number of bits to represent the page size for paged spaces. The value of 20
99 // gives 1Mb bytes per page.
100 const int kPageSizeBits = 20;
102 // On Intel architecture, cache line size is 64 bytes.
103 // On ARM it may be less (32 bytes), but as far this constant is
104 // used for aligning data, it doesn't hurt to align on a greater value.
105 const int kProcessorCacheLineSize = 64;
107 // Constants relevant to double precision floating point numbers.
108 // If looking only at the top 32 bits, the QNaN mask is bits 19 to 30.
109 const uint32_t kQuietNaNHighBitsMask = 0xfff << (51 - 32);
112 // -----------------------------------------------------------------------------
113 // Forward declarations for frequently used classes
119 class AssertNoAllocation;
128 class DescriptorArray;
129 class ExternalReference;
131 class FunctionTemplateInfo;
133 class SeededNumberDictionary;
134 class UnseededNumberDictionary;
135 class StringDictionary;
136 template <typename T> class Handle;
140 class InterceptorInfo;
144 class LargeObjectSpace;
146 class MacroAssembler;
149 class MarkCompactCollector;
159 template <typename Config, class Allocator = FreeStoreAllocationPolicy>
166 class MessageLocation;
172 typedef bool (*WeakSlotCallback)(Object** pointer);
174 typedef bool (*WeakSlotCallbackWithHeap)(Heap* heap, Object** pointer);
176 // -----------------------------------------------------------------------------
179 // NOTE: SpaceIterator depends on AllocationSpace enumeration values being
181 enum AllocationSpace {
182 NEW_SPACE, // Semispaces collected with copying collector.
183 OLD_POINTER_SPACE, // May contain pointers to new space.
184 OLD_DATA_SPACE, // Must not have pointers to new space.
185 CODE_SPACE, // No pointers to new space, marked executable.
186 MAP_SPACE, // Only and all map objects.
187 CELL_SPACE, // Only and all cell objects.
188 LO_SPACE, // Promoted large objects.
190 FIRST_SPACE = NEW_SPACE,
191 LAST_SPACE = LO_SPACE,
192 FIRST_PAGED_SPACE = OLD_POINTER_SPACE,
193 LAST_PAGED_SPACE = CELL_SPACE
195 const int kSpaceTagSize = 3;
196 const int kSpaceTagMask = (1 << kSpaceTagSize) - 1;
199 // A flag that indicates whether objects should be pretenured when
200 // allocated (allocated directly into the old generation) or not
201 // (allocated in the young generation if the object size and type
203 enum PretenureFlag { NOT_TENURED, TENURED };
205 enum GarbageCollector { SCAVENGER, MARK_COMPACTOR };
207 enum Executability { NOT_EXECUTABLE, EXECUTABLE };
211 VISIT_ALL_IN_SCAVENGE,
212 VISIT_ALL_IN_SWEEP_NEWSPACE,
216 // Flag indicating whether code is built into the VM (one of the natives files).
217 enum NativesFlag { NOT_NATIVES_CODE, NATIVES_CODE };
220 // A CodeDesc describes a buffer holding instructions and relocation
221 // information. The instructions start at the beginning of the buffer
222 // and grow forward, the relocation information starts at the end of
223 // the buffer and grows backward.
225 // |<--------------- buffer_size ---------------->|
226 // |<-- instr_size -->| |<-- reloc_size -->|
227 // +==================+========+==================+
228 // | instructions | free | reloc info |
229 // +==================+========+==================+
243 // Callback function used for iterating objects in heap spaces,
244 // for example, scanning heap objects.
245 typedef int (*HeapObjectCallback)(HeapObject* obj);
248 // Callback function used for checking constraints when copying/relocating
249 // objects. Returns true if an object can be copied/relocated from its
250 // old_addr to a new_addr.
251 typedef bool (*ConstraintCallback)(Address new_addr, Address old_addr);
254 // Callback function on inline caches, used for iterating over inline caches
256 typedef void (*InlineCacheCallback)(Code* code, Address ic);
259 // State for inline cache call sites. Aliased as IC::State.
260 enum InlineCacheState {
261 // Has never been executed.
263 // Has been executed but monomorhic state has been delayed.
265 // Has been executed and only one receiver type has been seen.
267 // Like MONOMORPHIC but check failed due to prototype.
268 MONOMORPHIC_PROTOTYPE_FAILURE,
269 // Multiple receiver types have been seen.
271 // Special states for debug break or step in prepare stubs.
273 DEBUG_PREPARE_STEP_IN
285 enum CallFunctionFlags {
286 NO_CALL_FUNCTION_FLAGS = 0,
287 // Receiver might implicitly be the global objects. If it is, the
288 // hole is passed to the call function stub.
289 RECEIVER_MIGHT_BE_IMPLICIT = 1 << 0,
290 // The call target is cached in the instruction stream.
291 RECORD_CALL_TARGET = 1 << 1
295 enum InlineCacheHolderFlag {
296 OWN_MAP, // For fast properties objects.
297 PROTOTYPE_MAP // For slow properties objects (except GlobalObjects).
301 // The Store Buffer (GC).
303 kStoreBufferFullEvent,
304 kStoreBufferStartScanningPagesEvent,
305 kStoreBufferScanningPageEvent
309 typedef void (*StoreBufferCallback)(Heap* heap,
311 StoreBufferEvent event);
314 // Whether to remove map transitions and constant transitions from a
316 enum TransitionFlag {
322 // Union used for fast testing of specific double values.
323 union DoubleRepresentation {
326 DoubleRepresentation(double x) { value = x; }
330 // Union used for customized checking of the IEEE double types
331 // inlined within v8 runtime, rather than going to the underlying
332 // platform headers and libraries
333 union IeeeDoubleLittleEndianArchType {
336 unsigned int man_low :32;
337 unsigned int man_high :20;
338 unsigned int exp :11;
339 unsigned int sign :1;
344 union IeeeDoubleBigEndianArchType {
347 unsigned int sign :1;
348 unsigned int exp :11;
349 unsigned int man_high :20;
350 unsigned int man_low :32;
356 struct AccessorDescriptor {
357 MaybeObject* (*getter)(Object* object, void* data);
358 MaybeObject* (*setter)(JSObject* object, Object* value, void* data);
363 // Logging and profiling. A StateTag represents a possible state of
364 // the VM. The logger maintains a stack of these. Creating a VMState
365 // object enters a state by pushing on the stack, and destroying a
366 // VMState object leaves a state by popping the current state from the
369 #define STATE_TAG_LIST(V) \
377 #define DEF_STATE_TAG(name) name,
378 STATE_TAG_LIST(DEF_STATE_TAG)
385 // -----------------------------------------------------------------------------
390 #define HAS_SMI_TAG(value) \
391 ((reinterpret_cast<intptr_t>(value) & kSmiTagMask) == kSmiTag)
393 #define HAS_FAILURE_TAG(value) \
394 ((reinterpret_cast<intptr_t>(value) & kFailureTagMask) == kFailureTag)
396 // OBJECT_POINTER_ALIGN returns the value aligned as a HeapObject pointer
397 #define OBJECT_POINTER_ALIGN(value) \
398 (((value) + kObjectAlignmentMask) & ~kObjectAlignmentMask)
400 // POINTER_SIZE_ALIGN returns the value aligned as a pointer.
401 #define POINTER_SIZE_ALIGN(value) \
402 (((value) + kPointerAlignmentMask) & ~kPointerAlignmentMask)
404 // MAP_POINTER_ALIGN returns the value aligned as a map pointer.
405 #define MAP_POINTER_ALIGN(value) \
406 (((value) + kMapAlignmentMask) & ~kMapAlignmentMask)
408 // CODE_POINTER_ALIGN returns the value aligned as a generated code segment.
409 #define CODE_POINTER_ALIGN(value) \
410 (((value) + kCodeAlignmentMask) & ~kCodeAlignmentMask)
412 // Support for tracking C++ memory allocation. Insert TRACK_MEMORY("Fisk")
413 // inside a C++ class and new and delete will be overloaded so logging is
415 // This file (globals.h) is included before log.h, so we use direct calls to
416 // the Logger rather than the LOG macro.
418 #define TRACK_MEMORY(name) \
419 void* operator new(size_t size) { \
420 void* result = ::operator new(size); \
421 Logger::NewEventStatic(name, result, size); \
424 void operator delete(void* object) { \
425 Logger::DeleteEventStatic(name, object); \
426 ::operator delete(object); \
429 #define TRACK_MEMORY(name)
433 // Feature flags bit positions. They are mostly based on the CPUID spec.
434 // (We assign CPUID itself to one of the currently reserved bits --
435 // feel free to change this if needed.)
436 // On X86/X64, values below 32 are bits in EDX, values above 32 are bits in ECX.
437 enum CpuFeature { SSE4_1 = 32 + 19, // x86
438 SSE3 = 32 + 0, // x86
449 // Used to specify if a macro instruction must perform a smi check on tagged
457 // Used to specify whether a receiver is implicitly or explicitly
458 // provided to a call.
466 EVAL_SCOPE, // The top-level scope for an eval source.
467 FUNCTION_SCOPE, // The top-level scope for a function.
468 MODULE_SCOPE, // The scope introduced by a module literal
469 GLOBAL_SCOPE, // The top-level scope for a program or a top-level eval.
470 CATCH_SCOPE, // The scope introduced by catch.
471 BLOCK_SCOPE, // The scope introduced by a new block.
472 WITH_SCOPE // The scope introduced by with.
476 const uint32_t kHoleNanUpper32 = 0x7FFFFFFF;
477 const uint32_t kHoleNanLower32 = 0xFFFFFFFF;
478 const uint32_t kNaNOrInfinityLowerBoundUpper32 = 0x7FF00000;
480 const uint64_t kHoleNanInt64 =
481 (static_cast<uint64_t>(kHoleNanUpper32) << 32) | kHoleNanLower32;
482 const uint64_t kLastNonNaNInt64 =
483 (static_cast<uint64_t>(kNaNOrInfinityLowerBoundUpper32) << 32);
487 // User declared variables:
488 VAR, // declared via 'var', and 'function' declarations
490 CONST, // declared via 'const' declarations
492 CONST_HARMONY, // declared via 'const' declarations in harmony mode
494 LET, // declared via 'let' declarations
496 // Variables introduced by the compiler:
497 DYNAMIC, // always require dynamic lookup (we don't know
500 DYNAMIC_GLOBAL, // requires dynamic lookup, but we know that the
501 // variable is global unless it has been shadowed
502 // by an eval-introduced variable
504 DYNAMIC_LOCAL, // requires dynamic lookup, but we know that the
505 // variable is local and where it is unless it
506 // has been shadowed by an eval-introduced
509 INTERNAL, // like VAR, but not user-visible (may or may not
512 TEMPORARY // temporary variables (not user-visible), never
517 // ES6 Draft Rev3 10.2 specifies declarative environment records with mutable
518 // and immutable bindings that can be in two states: initialized and
519 // uninitialized. In ES5 only immutable bindings have these two states. When
520 // accessing a binding, it needs to be checked for initialization. However in
521 // the following cases the binding is initialized immediately after creation
522 // so the initialization check can always be skipped:
523 // 1. Var declared local variables.
525 // 2. A local variable introduced by a function declaration.
528 // function x(foo) {}
529 // 4. Catch bound variables.
530 // try {} catch (foo) {}
531 // 6. Function variables of named function expressions.
532 // var x = function foo() {}
533 // 7. Implicit binding of 'this'.
534 // 8. Implicit binding of 'arguments' in functions.
536 // ES5 specified object environment records which are introduced by ES elements
537 // such as Program and WithStatement that associate identifier bindings with the
538 // properties of some object. In the specification only mutable bindings exist
539 // (which may be non-writable) and have no distinct initialization step. However
540 // V8 allows const declarations in global code with distinct creation and
541 // initialization steps which are represented by non-writable properties in the
542 // global object. As a result also these bindings need to be checked for
545 // The following enum specifies a flag that indicates if the binding needs a
546 // distinct initialization step (kNeedsInitialization) or if the binding is
547 // immediately initialized upon creation (kCreatedInitialized).
548 enum InitializationFlag {
549 kNeedsInitialization,
554 enum ClearExceptionFlag {
560 } } // namespace v8::internal
562 #endif // V8_V8GLOBALS_H_