/* [<][>][^][v][top][bottom][index][help] */
// Copyright 2012 the V8 project authors. All rights reserved.
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following
// disclaimer in the documentation and/or other materials provided
// with the distribution.
// * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived
// from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
// This module contains the platform-specific code. This make the rest of the
// code less dependent on operating system, compilers and runtime libraries.
// This module does specifically not deal with differences between different
// processor architecture.
// The platform classes have the same definition for all platforms. The
// implementation for a particular platform is put in platform_<os>.cc.
// The build system then uses the implementation for the target platform.
//
// This design has been chosen because it is simple and fast. Alternatively,
// the platform dependent classes could have been implemented using abstract
// superclasses with virtual methods and having specializations for each
// platform. This design was rejected because it was more complicated and
// slower. It would require factory methods for selecting the right
// implementation and the overhead of virtual methods for performance
// sensitive like mutex locking/unlocking.
#ifndef V8_PLATFORM_H_
#define V8_PLATFORM_H_
#ifdef __sun
# ifndef signbit
int signbit(double x);
# endif
#endif
// GCC specific stuff
#ifdef __GNUC__
// Needed for va_list on at least MinGW and Android.
#include <stdarg.h>
#define __GNUC_VERSION__ (__GNUC__ * 10000 + __GNUC_MINOR__ * 100)
#endif // __GNUC__
// Windows specific stuff.
#ifdef WIN32
// Microsoft Visual C++ specific stuff.
#ifdef _MSC_VER
#include "win32-math.h"
int strncasecmp(const char* s1, const char* s2, int n);
#endif // _MSC_VER
// Random is missing on both Visual Studio and MinGW.
int random();
#endif // WIN32
#include "atomicops.h"
#include "lazy-instance.h"
#include "platform-tls.h"
#include "utils.h"
#include "v8globals.h"
namespace v8 {
namespace internal {
// Use AtomicWord for a machine-sized pointer. It is assumed that
// reads and writes of naturally aligned values of this type are atomic.
typedef intptr_t AtomicWord;
class Semaphore;
class Mutex;
double ceiling(double x);
double modulo(double x, double y);
// Custom implementation of sin, cos, tan and log.
double fast_sin(double input);
double fast_cos(double input);
double fast_tan(double input);
double fast_log(double input);
double fast_sqrt(double input);
// Forward declarations.
class Socket;
// ----------------------------------------------------------------------------
// OS
//
// This class has static methods for the different platform specific
// functions. Add methods here to cope with differences between the
// supported platforms.
class OS {
public:
// Initializes the platform OS support. Called once at VM startup.
static void SetUp();
// Initializes the platform OS support that depend on CPU features. This is
// called after CPU initialization.
static void PostSetUp();
// Clean up platform-OS-related things. Called once at VM shutdown.
static void TearDown();
// Returns the accumulated user time for thread. This routine
// can be used for profiling. The implementation should
// strive for high-precision timer resolution, preferable
// micro-second resolution.
static int GetUserTime(uint32_t* secs, uint32_t* usecs);
// Get a tick counter normalized to one tick per microsecond.
// Used for calculating time intervals.
static int64_t Ticks();
// Returns current time as the number of milliseconds since
// 00:00:00 UTC, January 1, 1970.
static double TimeCurrentMillis();
// Returns a string identifying the current time zone. The
// timestamp is used for determining if DST is in effect.
static const char* LocalTimezone(double time);
// Returns the local time offset in milliseconds east of UTC without
// taking daylight savings time into account.
static double LocalTimeOffset();
// Returns the daylight savings offset for the given time.
static double DaylightSavingsOffset(double time);
// Returns last OS error.
static int GetLastError();
static FILE* FOpen(const char* path, const char* mode);
static bool Remove(const char* path);
// Opens a temporary file, the file is auto removed on close.
static FILE* OpenTemporaryFile();
// Log file open mode is platform-dependent due to line ends issues.
static const char* const LogFileOpenMode;
// Print output to console. This is mostly used for debugging output.
// On platforms that has standard terminal output, the output
// should go to stdout.
static void Print(const char* format, ...);
static void VPrint(const char* format, va_list args);
// Print output to a file. This is mostly used for debugging output.
static void FPrint(FILE* out, const char* format, ...);
static void VFPrint(FILE* out, const char* format, va_list args);
// Print error output to console. This is mostly used for error message
// output. On platforms that has standard terminal output, the output
// should go to stderr.
static void PrintError(const char* format, ...);
static void VPrintError(const char* format, va_list args);
// Allocate/Free memory used by JS heap. Pages are readable/writable, but
// they are not guaranteed to be executable unless 'executable' is true.
// Returns the address of allocated memory, or NULL if failed.
static void* Allocate(const size_t requested,
size_t* allocated,
bool is_executable);
static void Free(void* address, const size_t size);
// This is the granularity at which the ProtectCode(...) call can set page
// permissions.
static intptr_t CommitPageSize();
// Mark code segments non-writable.
static void ProtectCode(void* address, const size_t size);
// Assign memory as a guard page so that access will cause an exception.
static void Guard(void* address, const size_t size);
// Generate a random address to be used for hinting mmap().
static void* GetRandomMmapAddr();
// Get the Alignment guaranteed by Allocate().
static size_t AllocateAlignment();
// Returns an indication of whether a pointer is in a space that
// has been allocated by Allocate(). This method may conservatively
// always return false, but giving more accurate information may
// improve the robustness of the stack dump code in the presence of
// heap corruption.
static bool IsOutsideAllocatedSpace(void* pointer);
// Sleep for a number of milliseconds.
static void Sleep(const int milliseconds);
// Abort the current process.
static void Abort();
// Debug break.
static void DebugBreak();
// Walk the stack.
static const int kStackWalkError = -1;
static const int kStackWalkMaxNameLen = 256;
static const int kStackWalkMaxTextLen = 256;
struct StackFrame {
void* address;
char text[kStackWalkMaxTextLen];
};
static int StackWalk(Vector<StackFrame> frames);
// Factory method for creating platform dependent Mutex.
// Please use delete to reclaim the storage for the returned Mutex.
static Mutex* CreateMutex();
// Factory method for creating platform dependent Semaphore.
// Please use delete to reclaim the storage for the returned Semaphore.
static Semaphore* CreateSemaphore(int count);
// Factory method for creating platform dependent Socket.
// Please use delete to reclaim the storage for the returned Socket.
static Socket* CreateSocket();
class MemoryMappedFile {
public:
static MemoryMappedFile* open(const char* name);
static MemoryMappedFile* create(const char* name, int size, void* initial);
virtual ~MemoryMappedFile() { }
virtual void* memory() = 0;
virtual int size() = 0;
};
// Safe formatting print. Ensures that str is always null-terminated.
// Returns the number of chars written, or -1 if output was truncated.
static int SNPrintF(Vector<char> str, const char* format, ...);
static int VSNPrintF(Vector<char> str,
const char* format,
va_list args);
static char* StrChr(char* str, int c);
static void StrNCpy(Vector<char> dest, const char* src, size_t n);
// Support for the profiler. Can do nothing, in which case ticks
// occuring in shared libraries will not be properly accounted for.
static void LogSharedLibraryAddresses();
// Support for the profiler. Notifies the external profiling
// process that a code moving garbage collection starts. Can do
// nothing, in which case the code objects must not move (e.g., by
// using --never-compact) if accurate profiling is desired.
static void SignalCodeMovingGC();
// The return value indicates the CPU features we are sure of because of the
// OS. For example MacOSX doesn't run on any x86 CPUs that don't have SSE2
// instructions.
// This is a little messy because the interpretation is subject to the cross
// of the CPU and the OS. The bits in the answer correspond to the bit
// positions indicated by the members of the CpuFeature enum from globals.h
static uint64_t CpuFeaturesImpliedByPlatform();
// Maximum size of the virtual memory. 0 means there is no artificial
// limit.
static intptr_t MaxVirtualMemory();
// Returns the double constant NAN
static double nan_value();
// Support runtime detection of VFP3 on ARM CPUs.
static bool ArmCpuHasFeature(CpuFeature feature);
// Support runtime detection of whether the hard float option of the
// EABI is used.
static bool ArmUsingHardFloat();
// Support runtime detection of FPU on MIPS CPUs.
static bool MipsCpuHasFeature(CpuFeature feature);
// Returns the activation frame alignment constraint or zero if
// the platform doesn't care. Guaranteed to be a power of two.
static int ActivationFrameAlignment();
static void ReleaseStore(volatile AtomicWord* ptr, AtomicWord value);
#if defined(V8_TARGET_ARCH_IA32)
// Copy memory area to disjoint memory area.
static void MemCopy(void* dest, const void* src, size_t size);
// Limit below which the extra overhead of the MemCopy function is likely
// to outweigh the benefits of faster copying.
static const int kMinComplexMemCopy = 64;
typedef void (*MemCopyFunction)(void* dest, const void* src, size_t size);
#else // V8_TARGET_ARCH_IA32
static void MemCopy(void* dest, const void* src, size_t size) {
memcpy(dest, src, size);
}
static const int kMinComplexMemCopy = 256;
#endif // V8_TARGET_ARCH_IA32
static int GetCurrentProcessId();
private:
static const int msPerSecond = 1000;
DISALLOW_IMPLICIT_CONSTRUCTORS(OS);
};
// Represents and controls an area of reserved memory.
// Control of the reserved memory can be assigned to another VirtualMemory
// object by assignment or copy-contructing. This removes the reserved memory
// from the original object.
class VirtualMemory {
public:
// Empty VirtualMemory object, controlling no reserved memory.
VirtualMemory();
// Reserves virtual memory with size.
explicit VirtualMemory(size_t size);
// Reserves virtual memory containing an area of the given size that
// is aligned per alignment. This may not be at the position returned
// by address().
VirtualMemory(size_t size, size_t alignment);
// Releases the reserved memory, if any, controlled by this VirtualMemory
// object.
~VirtualMemory();
// Returns whether the memory has been reserved.
bool IsReserved();
// Initialize or resets an embedded VirtualMemory object.
void Reset();
// Returns the start address of the reserved memory.
// If the memory was reserved with an alignment, this address is not
// necessarily aligned. The user might need to round it up to a multiple of
// the alignment to get the start of the aligned block.
void* address() {
ASSERT(IsReserved());
return address_;
}
// Returns the size of the reserved memory. The returned value is only
// meaningful when IsReserved() returns true.
// If the memory was reserved with an alignment, this size may be larger
// than the requested size.
size_t size() { return size_; }
// Commits real memory. Returns whether the operation succeeded.
bool Commit(void* address, size_t size, bool is_executable);
// Uncommit real memory. Returns whether the operation succeeded.
bool Uncommit(void* address, size_t size);
// Creates a single guard page at the given address.
bool Guard(void* address);
void Release() {
ASSERT(IsReserved());
// Notice: Order is important here. The VirtualMemory object might live
// inside the allocated region.
void* address = address_;
size_t size = size_;
Reset();
bool result = ReleaseRegion(address, size);
USE(result);
ASSERT(result);
}
// Assign control of the reserved region to a different VirtualMemory object.
// The old object is no longer functional (IsReserved() returns false).
void TakeControl(VirtualMemory* from) {
ASSERT(!IsReserved());
address_ = from->address_;
size_ = from->size_;
from->Reset();
}
static void* ReserveRegion(size_t size);
static bool CommitRegion(void* base, size_t size, bool is_executable);
static bool UncommitRegion(void* base, size_t size);
// Must be called with a base pointer that has been returned by ReserveRegion
// and the same size it was reserved with.
static bool ReleaseRegion(void* base, size_t size);
private:
void* address_; // Start address of the virtual memory.
size_t size_; // Size of the virtual memory.
};
// ----------------------------------------------------------------------------
// Thread
//
// Thread objects are used for creating and running threads. When the start()
// method is called the new thread starts running the run() method in the new
// thread. The Thread object should not be deallocated before the thread has
// terminated.
class Thread {
public:
// Opaque data type for thread-local storage keys.
// LOCAL_STORAGE_KEY_MIN_VALUE and LOCAL_STORAGE_KEY_MAX_VALUE are specified
// to ensure that enumeration type has correct value range (see Issue 830 for
// more details).
enum LocalStorageKey {
LOCAL_STORAGE_KEY_MIN_VALUE = kMinInt,
LOCAL_STORAGE_KEY_MAX_VALUE = kMaxInt
};
class Options {
public:
Options() : name_("v8:<unknown>"), stack_size_(0) {}
Options(const char* name, int stack_size = 0)
: name_(name), stack_size_(stack_size) {}
const char* name() const { return name_; }
int stack_size() const { return stack_size_; }
private:
const char* name_;
int stack_size_;
};
// Create new thread.
explicit Thread(const Options& options);
virtual ~Thread();
// Start new thread by calling the Run() method in the new thread.
void Start();
// Wait until thread terminates.
void Join();
inline const char* name() const {
return name_;
}
// Abstract method for run handler.
virtual void Run() = 0;
// Thread-local storage.
static LocalStorageKey CreateThreadLocalKey();
static void DeleteThreadLocalKey(LocalStorageKey key);
static void* GetThreadLocal(LocalStorageKey key);
static int GetThreadLocalInt(LocalStorageKey key) {
return static_cast<int>(reinterpret_cast<intptr_t>(GetThreadLocal(key)));
}
static void SetThreadLocal(LocalStorageKey key, void* value);
static void SetThreadLocalInt(LocalStorageKey key, int value) {
SetThreadLocal(key, reinterpret_cast<void*>(static_cast<intptr_t>(value)));
}
static bool HasThreadLocal(LocalStorageKey key) {
return GetThreadLocal(key) != NULL;
}
#ifdef V8_FAST_TLS_SUPPORTED
static inline void* GetExistingThreadLocal(LocalStorageKey key) {
void* result = reinterpret_cast<void*>(
InternalGetExistingThreadLocal(static_cast<intptr_t>(key)));
ASSERT(result == GetThreadLocal(key));
return result;
}
#else
static inline void* GetExistingThreadLocal(LocalStorageKey key) {
return GetThreadLocal(key);
}
#endif
// A hint to the scheduler to let another thread run.
static void YieldCPU();
// The thread name length is limited to 16 based on Linux's implementation of
// prctl().
static const int kMaxThreadNameLength = 16;
class PlatformData;
PlatformData* data() { return data_; }
private:
void set_name(const char* name);
PlatformData* data_;
char name_[kMaxThreadNameLength];
int stack_size_;
DISALLOW_COPY_AND_ASSIGN(Thread);
};
// ----------------------------------------------------------------------------
// Mutex
//
// Mutexes are used for serializing access to non-reentrant sections of code.
// The implementations of mutex should allow for nested/recursive locking.
class Mutex {
public:
virtual ~Mutex() {}
// Locks the given mutex. If the mutex is currently unlocked, it becomes
// locked and owned by the calling thread, and immediately. If the mutex
// is already locked by another thread, suspends the calling thread until
// the mutex is unlocked.
virtual int Lock() = 0;
// Unlocks the given mutex. The mutex is assumed to be locked and owned by
// the calling thread on entrance.
virtual int Unlock() = 0;
// Tries to lock the given mutex. Returns whether the mutex was
// successfully locked.
virtual bool TryLock() = 0;
};
struct CreateMutexTrait {
static Mutex* Create() {
return OS::CreateMutex();
}
};
// POD Mutex initialized lazily (i.e. the first time Pointer() is called).
// Usage:
// static LazyMutex my_mutex = LAZY_MUTEX_INITIALIZER;
//
// void my_function() {
// ScopedLock my_lock(my_mutex.Pointer());
// // Do something.
// }
//
typedef LazyDynamicInstance<
Mutex, CreateMutexTrait, ThreadSafeInitOnceTrait>::type LazyMutex;
#define LAZY_MUTEX_INITIALIZER LAZY_DYNAMIC_INSTANCE_INITIALIZER
// ----------------------------------------------------------------------------
// ScopedLock
//
// Stack-allocated ScopedLocks provide block-scoped locking and
// unlocking of a mutex.
class ScopedLock {
public:
explicit ScopedLock(Mutex* mutex): mutex_(mutex) {
ASSERT(mutex_ != NULL);
mutex_->Lock();
}
~ScopedLock() {
mutex_->Unlock();
}
private:
Mutex* mutex_;
DISALLOW_COPY_AND_ASSIGN(ScopedLock);
};
// ----------------------------------------------------------------------------
// Semaphore
//
// A semaphore object is a synchronization object that maintains a count. The
// count is decremented each time a thread completes a wait for the semaphore
// object and incremented each time a thread signals the semaphore. When the
// count reaches zero, threads waiting for the semaphore blocks until the
// count becomes non-zero.
class Semaphore {
public:
virtual ~Semaphore() {}
// Suspends the calling thread until the semaphore counter is non zero
// and then decrements the semaphore counter.
virtual void Wait() = 0;
// Suspends the calling thread until the counter is non zero or the timeout
// time has passed. If timeout happens the return value is false and the
// counter is unchanged. Otherwise the semaphore counter is decremented and
// true is returned. The timeout value is specified in microseconds.
virtual bool Wait(int timeout) = 0;
// Increments the semaphore counter.
virtual void Signal() = 0;
};
template <int InitialValue>
struct CreateSemaphoreTrait {
static Semaphore* Create() {
return OS::CreateSemaphore(InitialValue);
}
};
// POD Semaphore initialized lazily (i.e. the first time Pointer() is called).
// Usage:
// // The following semaphore starts at 0.
// static LazySemaphore<0>::type my_semaphore = LAZY_SEMAPHORE_INITIALIZER;
//
// void my_function() {
// // Do something with my_semaphore.Pointer().
// }
//
template <int InitialValue>
struct LazySemaphore {
typedef typename LazyDynamicInstance<
Semaphore, CreateSemaphoreTrait<InitialValue>,
ThreadSafeInitOnceTrait>::type type;
};
#define LAZY_SEMAPHORE_INITIALIZER LAZY_DYNAMIC_INSTANCE_INITIALIZER
// ----------------------------------------------------------------------------
// Socket
//
class Socket {
public:
virtual ~Socket() {}
// Server initialization.
virtual bool Bind(const int port) = 0;
virtual bool Listen(int backlog) const = 0;
virtual Socket* Accept() const = 0;
// Client initialization.
virtual bool Connect(const char* host, const char* port) = 0;
// Shutdown socket for both read and write. This causes blocking Send and
// Receive calls to exit. After Shutdown the Socket object cannot be used for
// any communication.
virtual bool Shutdown() = 0;
// Data Transimission
// Return 0 on failure.
virtual int Send(const char* data, int len) const = 0;
virtual int Receive(char* data, int len) const = 0;
// Set the value of the SO_REUSEADDR socket option.
virtual bool SetReuseAddress(bool reuse_address) = 0;
virtual bool IsValid() const = 0;
static bool SetUp();
static int LastError();
static uint16_t HToN(uint16_t value);
static uint16_t NToH(uint16_t value);
static uint32_t HToN(uint32_t value);
static uint32_t NToH(uint32_t value);
};
// ----------------------------------------------------------------------------
// Sampler
//
// A sampler periodically samples the state of the VM and optionally
// (if used for profiling) the program counter and stack pointer for
// the thread that created it.
// TickSample captures the information collected for each sample.
class TickSample {
public:
TickSample()
: state(OTHER),
pc(NULL),
sp(NULL),
fp(NULL),
tos(NULL),
frames_count(0),
has_external_callback(false) {}
StateTag state; // The state of the VM.
Address pc; // Instruction pointer.
Address sp; // Stack pointer.
Address fp; // Frame pointer.
union {
Address tos; // Top stack value (*sp).
Address external_callback;
};
static const int kMaxFramesCount = 64;
Address stack[kMaxFramesCount]; // Call stack.
int frames_count : 8; // Number of captured frames.
bool has_external_callback : 1;
};
class Sampler {
public:
// Initialize sampler.
Sampler(Isolate* isolate, int interval);
virtual ~Sampler();
int interval() const { return interval_; }
// Performs stack sampling.
void SampleStack(TickSample* sample) {
DoSampleStack(sample);
IncSamplesTaken();
}
// This method is called for each sampling period with the current
// program counter.
virtual void Tick(TickSample* sample) = 0;
// Start and stop sampler.
void Start();
void Stop();
// Is the sampler used for profiling?
bool IsProfiling() const { return NoBarrier_Load(&profiling_) > 0; }
void IncreaseProfilingDepth() { NoBarrier_AtomicIncrement(&profiling_, 1); }
void DecreaseProfilingDepth() { NoBarrier_AtomicIncrement(&profiling_, -1); }
// Whether the sampler is running (that is, consumes resources).
bool IsActive() const { return NoBarrier_Load(&active_); }
Isolate* isolate() { return isolate_; }
// Used in tests to make sure that stack sampling is performed.
int samples_taken() const { return samples_taken_; }
void ResetSamplesTaken() { samples_taken_ = 0; }
class PlatformData;
PlatformData* data() { return data_; }
PlatformData* platform_data() { return data_; }
protected:
virtual void DoSampleStack(TickSample* sample) = 0;
private:
void SetActive(bool value) { NoBarrier_Store(&active_, value); }
void IncSamplesTaken() { if (++samples_taken_ < 0) samples_taken_ = 0; }
Isolate* isolate_;
const int interval_;
Atomic32 profiling_;
Atomic32 active_;
PlatformData* data_; // Platform specific data.
int samples_taken_; // Counts stack samples taken.
DISALLOW_IMPLICIT_CONSTRUCTORS(Sampler);
};
} } // namespace v8::internal
#endif // V8_PLATFORM_H_