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Add V8_ALIGNAS() and V8_ALIGNOF() and use that in lazy-instance.h.

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This renames the existing V8_ALIGNAS() to V8_ALIGNED(), and introduces
V8_ALIGNAS(type, alignment) which aligns according to the type and falls
back to aligning according to alignment.

Also use __attribute__((aligned(n))) instead of __attribute__((__aligned__(n))).

R=svenpanne@chromium.org

Review URL: https://codereview.chromium.org/22999052

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@16318 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
This commit is contained in:
bmeurer@chromium.org 2013-08-26 11:18:28 +00:00
parent 1873546031
commit 10a4570282
3 changed files with 71 additions and 24 deletions
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70
include/v8config.h
View File

@ -97,6 +97,7 @@
// C++11 feature detection
//
// V8_HAS_CXX11_ALIGNAS - alignas specifier supported
// V8_HAS_CXX11_ALIGNOF - alignof(type) operator supported
// V8_HAS_CXX11_STATIC_ASSERT - static_assert() supported
// V8_HAS_CXX11_DELETE - deleted functions supported
// V8_HAS_CXX11_FINAL - final marker supported
@ -104,7 +105,9 @@
//
// Compiler-specific feature detection
//
// V8_HAS_ATTRIBUTE___ALIGNED__ - __attribute__((__aligned__(n))) supported
// V8_HAS___ALIGNOF - __alignof(type) operator supported
// V8_HAS___ALIGNOF__ - __alignof__(type) operator supported
// V8_HAS_ATTRIBUTE_ALIGNED - __attribute__((aligned(n))) supported
// V8_HAS_ATTRIBUTE_ALWAYS_INLINE - __attribute__((always_inline)) supported
// V8_HAS_ATTRIBUTE_DEPRECATED - __attribute__((deprecated)) supported
// V8_HAS_ATTRIBUTE_VISIBILITY - __attribute__((visibility)) supported
@ -122,7 +125,11 @@
# define V8_CC_CLANG 1
# define V8_HAS_ATTRIBUTE___ALIGNED__ (__has_attribute(__aligned__))
// Clang defines __alignof__ as alias for __alignof
# define V8_HAS___ALIGNOF 1
# define V8_HAS___ALIGNOF__ V8_HAS___ALIGNOF
# define V8_HAS_ATTRIBUTE_ALIGNED (__has_attribute(aligned))
# define V8_HAS_ATTRIBUTE_ALWAYS_INLINE (__has_attribute(always_inline))
# define V8_HAS_ATTRIBUTE_DEPRECATED (__has_attribute(deprecated))
# define V8_HAS_ATTRIBUTE_VISIBILITY (__has_attribute(visibility))
@ -146,7 +153,9 @@
# define V8_CC_MINGW 1
# endif
# define V8_HAS_ATTRIBUTE___ALIGNED__ (V8_GNUC_PREREQ(2, 95, 0))
# define V8_HAS___ALIGNOF__ (V8_GNUC_PREREQ(4, 3, 0))
# define V8_HAS_ATTRIBUTE_ALIGNED (V8_GNUC_PREREQ(2, 95, 0))
// always_inline is available in gcc 4.0 but not very reliable until 4.4.
// Works around "sorry, unimplemented: inlining failed" build errors with
// older compilers.
@ -164,6 +173,7 @@
// both for forward compatibility.
# if defined(__GXX_EXPERIMENTAL_CXX0X__) || __cplusplus >= 201103L
# define V8_HAS_CXX11_ALIGNAS (V8_GNUC_PREREQ(4, 8, 0))
# define V8_HAS_CXX11_ALIGNOF (V8_GNUC_PREREQ(4, 8, 0))
# define V8_HAS_CXX11_STATIC_ASSERT (V8_GNUC_PREREQ(4, 3, 0))
# define V8_HAS_CXX11_DELETE (V8_GNUC_PREREQ(4, 4, 0))
# define V8_HAS_CXX11_OVERRIDE (V8_GNUC_PREREQ(4, 7, 0))
@ -179,6 +189,8 @@
# define V8_CC_MSVC 1
# define V8_HAS___ALIGNOF 1
// Override control was added with Visual Studio 2005, but
// Visual Studio 2010 and earlier spell "final" as "sealed".
# define V8_HAS_CXX11_FINAL (_MSC_VER >= 1700)
@ -275,16 +287,54 @@
// This macro allows to specify memory alignment for structs, classes, etc.
// Use like:
// class V8_ALIGNAS(16) MyClass { ... };
// V8_ALIGNAS(32) int array[42];
// class V8_ALIGNED(16) MyClass { ... };
// V8_ALIGNED(32) int array[42];
#if V8_HAS_CXX11_ALIGNAS
# define V8_ALIGNAS(n) alignas(n)
#elif V8_HAS_ATTRIBUTE___ALIGNED__
# define V8_ALIGNAS(n) __attribute__((__aligned__(n)))
# define V8_ALIGNED(n) alignas(n)
#elif V8_HAS_ATTRIBUTE_ALIGNED
# define V8_ALIGNED(n) __attribute__((aligned(n)))
#elif V8_HAS_DECLSPEC_ALIGN
# define V8_ALIGNAS(n) __declspec(align(n))
# define V8_ALIGNED(n) __declspec(align(n))
#else
# define V8_ALIGNAS(n) /* NOT SUPPORTED */
# define V8_ALIGNED(n) /* NOT SUPPORTED */
#endif
// This macro is similar to V8_ALIGNED(), but takes a type instead of size
// in bytes. If the compiler does not supports using the alignment of the
// |type|, it will align according to the |alignment| instead. For example,
// Visual Studio C++ cannot combine __declspec(align) and __alignof. The
// |alignment| must be a literal that is used as a kind of worst-case fallback
// alignment.
// Use like:
// struct V8_ALIGNAS(AnotherClass, 16) NewClass { ... };
// V8_ALIGNAS(double, 8) int array[100];
#if V8_HAS_CXX11_ALIGNAS
# define V8_ALIGNAS(type, alignment) alignas(type)
#elif V8_HAS___ALIGNOF__ && V8_HAS_ATTRIBUTE_ALIGNED
# define V8_ALIGNAS(type, alignment) __attribute__((aligned(__alignof__(type))))
#else
# define V8_ALIGNAS(type, alignment) V8_ALIGNED(alignment)
#endif
// This macro returns alignment in bytes (an integer power of two) required for
// any instance of the given type, which is either complete type, an array type,
// or a reference type.
// Use like:
// size_t alignment = V8_ALIGNOF(double);
#if V8_HAS_CXX11_ALIGNOF
# define V8_ALIGNOF(type) alignof(type)
#elif V8_HAS___ALIGNOF
# define V8_ALIGNOF(type) __alignof(type)
#elif V8_HAS___ALIGNOF__
# define V8_ALIGNOF(type) __alignof__(type)
#else
// Note that alignment of a type within a struct can be less than the
// alignment of the type stand-alone (because of ancient ABIs), so this
// should only be used as a last resort.
namespace v8 { template <typename T> class AlignOfHelper { char c; T t; }; }
# define V8_ALIGNOF(type) (sizeof(::v8::AlignOfHelper<type>) - sizeof(type))
#endif
#endif // V8CONFIG_H_

6
src/circular-queue.h
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@ -70,7 +70,7 @@ class SamplingCircularQueue {
// completely processed by the consumer.
};
struct V8_ALIGNAS(PROCESSOR_CACHE_LINE_SIZE) Entry {
struct V8_ALIGNED(PROCESSOR_CACHE_LINE_SIZE) Entry {
Entry() : marker(kEmpty) {}
T record;
Atomic32 marker;
@ -79,8 +79,8 @@ class SamplingCircularQueue {
Entry* Next(Entry* entry);
Entry buffer_[Length];
V8_ALIGNAS(PROCESSOR_CACHE_LINE_SIZE) Entry* enqueue_pos_;
V8_ALIGNAS(PROCESSOR_CACHE_LINE_SIZE) Entry* dequeue_pos_;
V8_ALIGNED(PROCESSOR_CACHE_LINE_SIZE) Entry* enqueue_pos_;
V8_ALIGNED(PROCESSOR_CACHE_LINE_SIZE) Entry* dequeue_pos_;
DISALLOW_COPY_AND_ASSIGN(SamplingCircularQueue);
};

19
src/lazy-instance.h
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@ -91,12 +91,13 @@
#ifndef V8_LAZY_INSTANCE_H_
#define V8_LAZY_INSTANCE_H_
#include "checks.h"
#include "once.h"
namespace v8 {
namespace internal {
#define LAZY_STATIC_INSTANCE_INITIALIZER { V8_ONCE_INIT, {} }
#define LAZY_STATIC_INSTANCE_INITIALIZER { V8_ONCE_INIT, { {} } }
#define LAZY_DYNAMIC_INSTANCE_INITIALIZER { V8_ONCE_INIT, 0 }
// Default to static mode.
@ -111,17 +112,15 @@ struct LeakyInstanceTrait {
// Traits that define how an instance is allocated and accessed.
// TODO(kalmard): __alignof__ is only defined for GCC > 4.2. Fix alignment issue
// on MIPS with other compilers.
#if defined(__GNUC__) && (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ > 2))
#define LAZY_ALIGN(x) __attribute__((aligned(__alignof__(x))))
#else
#define LAZY_ALIGN(x)
#endif
template <typename T>
struct StaticallyAllocatedInstanceTrait {
typedef char StorageType[sizeof(T)] LAZY_ALIGN(T);
// 16-byte alignment fallback to be on the safe side here.
struct V8_ALIGNAS(T, 16) StorageType {
char x[sizeof(T)];
};
STATIC_ASSERT(V8_ALIGNOF(StorageType) >= V8_ALIGNOF(T));
static T* MutableInstance(StorageType* storage) {
return reinterpret_cast<T*>(storage);
@ -133,8 +132,6 @@ struct StaticallyAllocatedInstanceTrait {
}
};
#undef LAZY_ALIGN
template <typename T>
struct DynamicallyAllocatedInstanceTrait {