Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame^] | 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 |
| 3 | // found in the LICENSE file. |
| 4 | |
| 5 | // This module contains the platform-specific code. This make the rest of the |
| 6 | // code less dependent on operating system, compilers and runtime libraries. |
| 7 | // This module does specifically not deal with differences between different |
| 8 | // processor architecture. |
| 9 | // The platform classes have the same definition for all platforms. The |
| 10 | // implementation for a particular platform is put in platform_<os>.cc. |
| 11 | // The build system then uses the implementation for the target platform. |
| 12 | // |
| 13 | // This design has been chosen because it is simple and fast. Alternatively, |
| 14 | // the platform dependent classes could have been implemented using abstract |
| 15 | // superclasses with virtual methods and having specializations for each |
| 16 | // platform. This design was rejected because it was more complicated and |
| 17 | // slower. It would require factory methods for selecting the right |
| 18 | // implementation and the overhead of virtual methods for performance |
| 19 | // sensitive like mutex locking/unlocking. |
| 20 | |
| 21 | #ifndef V8_BASE_PLATFORM_PLATFORM_H_ |
| 22 | #define V8_BASE_PLATFORM_PLATFORM_H_ |
| 23 | |
| 24 | #include <stdarg.h> |
| 25 | #include <string> |
| 26 | #include <vector> |
| 27 | |
| 28 | #include "src/base/build_config.h" |
| 29 | #include "src/base/platform/mutex.h" |
| 30 | #include "src/base/platform/semaphore.h" |
| 31 | |
| 32 | #ifdef __sun |
| 33 | # ifndef signbit |
| 34 | namespace std { |
| 35 | int signbit(double x); |
| 36 | } |
| 37 | # endif |
| 38 | #endif |
| 39 | |
| 40 | #if V8_OS_QNX |
| 41 | #include "src/base/qnx-math.h" |
| 42 | #endif |
| 43 | |
| 44 | // Microsoft Visual C++ specific stuff. |
| 45 | #if V8_LIBC_MSVCRT |
| 46 | |
| 47 | #include "src/base/win32-headers.h" |
| 48 | #include "src/base/win32-math.h" |
| 49 | |
| 50 | int strncasecmp(const char* s1, const char* s2, int n); |
| 51 | |
| 52 | // Visual C++ 2013 and higher implement this function. |
| 53 | #if (_MSC_VER < 1800) |
| 54 | inline int lrint(double flt) { |
| 55 | int intgr; |
| 56 | #if V8_TARGET_ARCH_IA32 || V8_TARGET_ARCH_X87 |
| 57 | __asm { |
| 58 | fld flt |
| 59 | fistp intgr |
| 60 | }; |
| 61 | #else |
| 62 | intgr = static_cast<int>(flt + 0.5); |
| 63 | if ((intgr & 1) != 0 && intgr - flt == 0.5) { |
| 64 | // If the number is halfway between two integers, round to the even one. |
| 65 | intgr--; |
| 66 | } |
| 67 | #endif |
| 68 | return intgr; |
| 69 | } |
| 70 | #endif // _MSC_VER < 1800 |
| 71 | |
| 72 | #endif // V8_LIBC_MSVCRT |
| 73 | |
| 74 | namespace v8 { |
| 75 | namespace base { |
| 76 | |
| 77 | // ---------------------------------------------------------------------------- |
| 78 | // Fast TLS support |
| 79 | |
| 80 | #ifndef V8_NO_FAST_TLS |
| 81 | |
| 82 | #if defined(_MSC_VER) && (V8_HOST_ARCH_IA32) |
| 83 | |
| 84 | #define V8_FAST_TLS_SUPPORTED 1 |
| 85 | |
| 86 | INLINE(intptr_t InternalGetExistingThreadLocal(intptr_t index)); |
| 87 | |
| 88 | inline intptr_t InternalGetExistingThreadLocal(intptr_t index) { |
| 89 | const intptr_t kTibInlineTlsOffset = 0xE10; |
| 90 | const intptr_t kTibExtraTlsOffset = 0xF94; |
| 91 | const intptr_t kMaxInlineSlots = 64; |
| 92 | const intptr_t kMaxSlots = kMaxInlineSlots + 1024; |
| 93 | const intptr_t kPointerSize = sizeof(void*); |
| 94 | DCHECK(0 <= index && index < kMaxSlots); |
| 95 | if (index < kMaxInlineSlots) { |
| 96 | return static_cast<intptr_t>(__readfsdword(kTibInlineTlsOffset + |
| 97 | kPointerSize * index)); |
| 98 | } |
| 99 | intptr_t extra = static_cast<intptr_t>(__readfsdword(kTibExtraTlsOffset)); |
| 100 | DCHECK(extra != 0); |
| 101 | return *reinterpret_cast<intptr_t*>(extra + |
| 102 | kPointerSize * (index - kMaxInlineSlots)); |
| 103 | } |
| 104 | |
| 105 | #elif defined(__APPLE__) && (V8_HOST_ARCH_IA32 || V8_HOST_ARCH_X64) |
| 106 | |
| 107 | #define V8_FAST_TLS_SUPPORTED 1 |
| 108 | |
| 109 | extern intptr_t kMacTlsBaseOffset; |
| 110 | |
| 111 | INLINE(intptr_t InternalGetExistingThreadLocal(intptr_t index)); |
| 112 | |
| 113 | inline intptr_t InternalGetExistingThreadLocal(intptr_t index) { |
| 114 | intptr_t result; |
| 115 | #if V8_HOST_ARCH_IA32 |
| 116 | asm("movl %%gs:(%1,%2,4), %0;" |
| 117 | :"=r"(result) // Output must be a writable register. |
| 118 | :"r"(kMacTlsBaseOffset), "r"(index)); |
| 119 | #else |
| 120 | asm("movq %%gs:(%1,%2,8), %0;" |
| 121 | :"=r"(result) |
| 122 | :"r"(kMacTlsBaseOffset), "r"(index)); |
| 123 | #endif |
| 124 | return result; |
| 125 | } |
| 126 | |
| 127 | #endif |
| 128 | |
| 129 | #endif // V8_NO_FAST_TLS |
| 130 | |
| 131 | |
| 132 | class TimezoneCache; |
| 133 | |
| 134 | |
| 135 | // ---------------------------------------------------------------------------- |
| 136 | // OS |
| 137 | // |
| 138 | // This class has static methods for the different platform specific |
| 139 | // functions. Add methods here to cope with differences between the |
| 140 | // supported platforms. |
| 141 | |
| 142 | class OS { |
| 143 | public: |
| 144 | // Initialize the OS class. |
| 145 | // - random_seed: Used for the GetRandomMmapAddress() if non-zero. |
| 146 | // - hard_abort: If true, OS::Abort() will crash instead of aborting. |
| 147 | // - gc_fake_mmap: Name of the file for fake gc mmap used in ll_prof. |
| 148 | static void Initialize(int64_t random_seed, |
| 149 | bool hard_abort, |
| 150 | const char* const gc_fake_mmap); |
| 151 | |
| 152 | // Returns the accumulated user time for thread. This routine |
| 153 | // can be used for profiling. The implementation should |
| 154 | // strive for high-precision timer resolution, preferable |
| 155 | // micro-second resolution. |
| 156 | static int GetUserTime(uint32_t* secs, uint32_t* usecs); |
| 157 | |
| 158 | // Returns current time as the number of milliseconds since |
| 159 | // 00:00:00 UTC, January 1, 1970. |
| 160 | static double TimeCurrentMillis(); |
| 161 | |
| 162 | static TimezoneCache* CreateTimezoneCache(); |
| 163 | static void DisposeTimezoneCache(TimezoneCache* cache); |
| 164 | static void ClearTimezoneCache(TimezoneCache* cache); |
| 165 | |
| 166 | // Returns a string identifying the current time zone. The |
| 167 | // timestamp is used for determining if DST is in effect. |
| 168 | static const char* LocalTimezone(double time, TimezoneCache* cache); |
| 169 | |
| 170 | // Returns the local time offset in milliseconds east of UTC without |
| 171 | // taking daylight savings time into account. |
| 172 | static double LocalTimeOffset(TimezoneCache* cache); |
| 173 | |
| 174 | // Returns the daylight savings offset for the given time. |
| 175 | static double DaylightSavingsOffset(double time, TimezoneCache* cache); |
| 176 | |
| 177 | // Returns last OS error. |
| 178 | static int GetLastError(); |
| 179 | |
| 180 | static FILE* FOpen(const char* path, const char* mode); |
| 181 | static bool Remove(const char* path); |
| 182 | |
| 183 | // Opens a temporary file, the file is auto removed on close. |
| 184 | static FILE* OpenTemporaryFile(); |
| 185 | |
| 186 | // Log file open mode is platform-dependent due to line ends issues. |
| 187 | static const char* const LogFileOpenMode; |
| 188 | |
| 189 | // Print output to console. This is mostly used for debugging output. |
| 190 | // On platforms that has standard terminal output, the output |
| 191 | // should go to stdout. |
| 192 | static void Print(const char* format, ...); |
| 193 | static void VPrint(const char* format, va_list args); |
| 194 | |
| 195 | // Print output to a file. This is mostly used for debugging output. |
| 196 | static void FPrint(FILE* out, const char* format, ...); |
| 197 | static void VFPrint(FILE* out, const char* format, va_list args); |
| 198 | |
| 199 | // Print error output to console. This is mostly used for error message |
| 200 | // output. On platforms that has standard terminal output, the output |
| 201 | // should go to stderr. |
| 202 | static void PrintError(const char* format, ...); |
| 203 | static void VPrintError(const char* format, va_list args); |
| 204 | |
| 205 | // Allocate/Free memory used by JS heap. Pages are readable/writable, but |
| 206 | // they are not guaranteed to be executable unless 'executable' is true. |
| 207 | // Returns the address of allocated memory, or NULL if failed. |
| 208 | static void* Allocate(const size_t requested, |
| 209 | size_t* allocated, |
| 210 | bool is_executable); |
| 211 | static void Free(void* address, const size_t size); |
| 212 | |
| 213 | // This is the granularity at which the ProtectCode(...) call can set page |
| 214 | // permissions. |
| 215 | static intptr_t CommitPageSize(); |
| 216 | |
| 217 | // Mark code segments non-writable. |
| 218 | static void ProtectCode(void* address, const size_t size); |
| 219 | |
| 220 | // Assign memory as a guard page so that access will cause an exception. |
| 221 | static void Guard(void* address, const size_t size); |
| 222 | |
| 223 | // Generate a random address to be used for hinting mmap(). |
| 224 | static void* GetRandomMmapAddr(); |
| 225 | |
| 226 | // Get the Alignment guaranteed by Allocate(). |
| 227 | static size_t AllocateAlignment(); |
| 228 | |
| 229 | // Sleep for a number of milliseconds. |
| 230 | static void Sleep(const int milliseconds); |
| 231 | |
| 232 | // Abort the current process. |
| 233 | static void Abort(); |
| 234 | |
| 235 | // Debug break. |
| 236 | static void DebugBreak(); |
| 237 | |
| 238 | // Walk the stack. |
| 239 | static const int kStackWalkError = -1; |
| 240 | static const int kStackWalkMaxNameLen = 256; |
| 241 | static const int kStackWalkMaxTextLen = 256; |
| 242 | struct StackFrame { |
| 243 | void* address; |
| 244 | char text[kStackWalkMaxTextLen]; |
| 245 | }; |
| 246 | |
| 247 | class MemoryMappedFile { |
| 248 | public: |
| 249 | static MemoryMappedFile* open(const char* name); |
| 250 | static MemoryMappedFile* create(const char* name, int size, void* initial); |
| 251 | virtual ~MemoryMappedFile() { } |
| 252 | virtual void* memory() = 0; |
| 253 | virtual int size() = 0; |
| 254 | }; |
| 255 | |
| 256 | // Safe formatting print. Ensures that str is always null-terminated. |
| 257 | // Returns the number of chars written, or -1 if output was truncated. |
| 258 | static int SNPrintF(char* str, int length, const char* format, ...); |
| 259 | static int VSNPrintF(char* str, |
| 260 | int length, |
| 261 | const char* format, |
| 262 | va_list args); |
| 263 | |
| 264 | static char* StrChr(char* str, int c); |
| 265 | static void StrNCpy(char* dest, int length, const char* src, size_t n); |
| 266 | |
| 267 | // Support for the profiler. Can do nothing, in which case ticks |
| 268 | // occuring in shared libraries will not be properly accounted for. |
| 269 | struct SharedLibraryAddress { |
| 270 | SharedLibraryAddress( |
| 271 | const std::string& library_path, uintptr_t start, uintptr_t end) |
| 272 | : library_path(library_path), start(start), end(end) {} |
| 273 | |
| 274 | std::string library_path; |
| 275 | uintptr_t start; |
| 276 | uintptr_t end; |
| 277 | }; |
| 278 | |
| 279 | static std::vector<SharedLibraryAddress> GetSharedLibraryAddresses(); |
| 280 | |
| 281 | // Support for the profiler. Notifies the external profiling |
| 282 | // process that a code moving garbage collection starts. Can do |
| 283 | // nothing, in which case the code objects must not move (e.g., by |
| 284 | // using --never-compact) if accurate profiling is desired. |
| 285 | static void SignalCodeMovingGC(); |
| 286 | |
| 287 | // Returns the double constant NAN |
| 288 | static double nan_value(); |
| 289 | |
| 290 | // Support runtime detection of whether the hard float option of the |
| 291 | // EABI is used. |
| 292 | static bool ArmUsingHardFloat(); |
| 293 | |
| 294 | // Returns the activation frame alignment constraint or zero if |
| 295 | // the platform doesn't care. Guaranteed to be a power of two. |
| 296 | static int ActivationFrameAlignment(); |
| 297 | |
| 298 | static int GetCurrentProcessId(); |
| 299 | |
| 300 | static int GetCurrentThreadId(); |
| 301 | |
| 302 | private: |
| 303 | static const int msPerSecond = 1000; |
| 304 | |
| 305 | #if V8_OS_POSIX |
| 306 | static const char* GetGCFakeMMapFile(); |
| 307 | #endif |
| 308 | |
| 309 | DISALLOW_IMPLICIT_CONSTRUCTORS(OS); |
| 310 | }; |
| 311 | |
| 312 | // Represents and controls an area of reserved memory. |
| 313 | // Control of the reserved memory can be assigned to another VirtualMemory |
| 314 | // object by assignment or copy-contructing. This removes the reserved memory |
| 315 | // from the original object. |
| 316 | class VirtualMemory { |
| 317 | public: |
| 318 | // Empty VirtualMemory object, controlling no reserved memory. |
| 319 | VirtualMemory(); |
| 320 | |
| 321 | // Reserves virtual memory with size. |
| 322 | explicit VirtualMemory(size_t size); |
| 323 | |
| 324 | // Reserves virtual memory containing an area of the given size that |
| 325 | // is aligned per alignment. This may not be at the position returned |
| 326 | // by address(). |
| 327 | VirtualMemory(size_t size, size_t alignment); |
| 328 | |
| 329 | // Releases the reserved memory, if any, controlled by this VirtualMemory |
| 330 | // object. |
| 331 | ~VirtualMemory(); |
| 332 | |
| 333 | // Returns whether the memory has been reserved. |
| 334 | bool IsReserved(); |
| 335 | |
| 336 | // Initialize or resets an embedded VirtualMemory object. |
| 337 | void Reset(); |
| 338 | |
| 339 | // Returns the start address of the reserved memory. |
| 340 | // If the memory was reserved with an alignment, this address is not |
| 341 | // necessarily aligned. The user might need to round it up to a multiple of |
| 342 | // the alignment to get the start of the aligned block. |
| 343 | void* address() { |
| 344 | DCHECK(IsReserved()); |
| 345 | return address_; |
| 346 | } |
| 347 | |
| 348 | // Returns the size of the reserved memory. The returned value is only |
| 349 | // meaningful when IsReserved() returns true. |
| 350 | // If the memory was reserved with an alignment, this size may be larger |
| 351 | // than the requested size. |
| 352 | size_t size() { return size_; } |
| 353 | |
| 354 | // Commits real memory. Returns whether the operation succeeded. |
| 355 | bool Commit(void* address, size_t size, bool is_executable); |
| 356 | |
| 357 | // Uncommit real memory. Returns whether the operation succeeded. |
| 358 | bool Uncommit(void* address, size_t size); |
| 359 | |
| 360 | // Creates a single guard page at the given address. |
| 361 | bool Guard(void* address); |
| 362 | |
| 363 | void Release() { |
| 364 | DCHECK(IsReserved()); |
| 365 | // Notice: Order is important here. The VirtualMemory object might live |
| 366 | // inside the allocated region. |
| 367 | void* address = address_; |
| 368 | size_t size = size_; |
| 369 | Reset(); |
| 370 | bool result = ReleaseRegion(address, size); |
| 371 | USE(result); |
| 372 | DCHECK(result); |
| 373 | } |
| 374 | |
| 375 | // Assign control of the reserved region to a different VirtualMemory object. |
| 376 | // The old object is no longer functional (IsReserved() returns false). |
| 377 | void TakeControl(VirtualMemory* from) { |
| 378 | DCHECK(!IsReserved()); |
| 379 | address_ = from->address_; |
| 380 | size_ = from->size_; |
| 381 | from->Reset(); |
| 382 | } |
| 383 | |
| 384 | static void* ReserveRegion(size_t size); |
| 385 | |
| 386 | static bool CommitRegion(void* base, size_t size, bool is_executable); |
| 387 | |
| 388 | static bool UncommitRegion(void* base, size_t size); |
| 389 | |
| 390 | // Must be called with a base pointer that has been returned by ReserveRegion |
| 391 | // and the same size it was reserved with. |
| 392 | static bool ReleaseRegion(void* base, size_t size); |
| 393 | |
| 394 | // Returns true if OS performs lazy commits, i.e. the memory allocation call |
| 395 | // defers actual physical memory allocation till the first memory access. |
| 396 | // Otherwise returns false. |
| 397 | static bool HasLazyCommits(); |
| 398 | |
| 399 | private: |
| 400 | void* address_; // Start address of the virtual memory. |
| 401 | size_t size_; // Size of the virtual memory. |
| 402 | }; |
| 403 | |
| 404 | |
| 405 | // ---------------------------------------------------------------------------- |
| 406 | // Thread |
| 407 | // |
| 408 | // Thread objects are used for creating and running threads. When the start() |
| 409 | // method is called the new thread starts running the run() method in the new |
| 410 | // thread. The Thread object should not be deallocated before the thread has |
| 411 | // terminated. |
| 412 | |
| 413 | class Thread { |
| 414 | public: |
| 415 | // Opaque data type for thread-local storage keys. |
| 416 | typedef int32_t LocalStorageKey; |
| 417 | |
| 418 | class Options { |
| 419 | public: |
| 420 | Options() : name_("v8:<unknown>"), stack_size_(0) {} |
| 421 | explicit Options(const char* name, int stack_size = 0) |
| 422 | : name_(name), stack_size_(stack_size) {} |
| 423 | |
| 424 | const char* name() const { return name_; } |
| 425 | int stack_size() const { return stack_size_; } |
| 426 | |
| 427 | private: |
| 428 | const char* name_; |
| 429 | int stack_size_; |
| 430 | }; |
| 431 | |
| 432 | // Create new thread. |
| 433 | explicit Thread(const Options& options); |
| 434 | virtual ~Thread(); |
| 435 | |
| 436 | // Start new thread by calling the Run() method on the new thread. |
| 437 | void Start(); |
| 438 | |
| 439 | // Start new thread and wait until Run() method is called on the new thread. |
| 440 | void StartSynchronously() { |
| 441 | start_semaphore_ = new Semaphore(0); |
| 442 | Start(); |
| 443 | start_semaphore_->Wait(); |
| 444 | delete start_semaphore_; |
| 445 | start_semaphore_ = NULL; |
| 446 | } |
| 447 | |
| 448 | // Wait until thread terminates. |
| 449 | void Join(); |
| 450 | |
| 451 | inline const char* name() const { |
| 452 | return name_; |
| 453 | } |
| 454 | |
| 455 | // Abstract method for run handler. |
| 456 | virtual void Run() = 0; |
| 457 | |
| 458 | // Thread-local storage. |
| 459 | static LocalStorageKey CreateThreadLocalKey(); |
| 460 | static void DeleteThreadLocalKey(LocalStorageKey key); |
| 461 | static void* GetThreadLocal(LocalStorageKey key); |
| 462 | static int GetThreadLocalInt(LocalStorageKey key) { |
| 463 | return static_cast<int>(reinterpret_cast<intptr_t>(GetThreadLocal(key))); |
| 464 | } |
| 465 | static void SetThreadLocal(LocalStorageKey key, void* value); |
| 466 | static void SetThreadLocalInt(LocalStorageKey key, int value) { |
| 467 | SetThreadLocal(key, reinterpret_cast<void*>(static_cast<intptr_t>(value))); |
| 468 | } |
| 469 | static bool HasThreadLocal(LocalStorageKey key) { |
| 470 | return GetThreadLocal(key) != NULL; |
| 471 | } |
| 472 | |
| 473 | #ifdef V8_FAST_TLS_SUPPORTED |
| 474 | static inline void* GetExistingThreadLocal(LocalStorageKey key) { |
| 475 | void* result = reinterpret_cast<void*>( |
| 476 | InternalGetExistingThreadLocal(static_cast<intptr_t>(key))); |
| 477 | DCHECK(result == GetThreadLocal(key)); |
| 478 | return result; |
| 479 | } |
| 480 | #else |
| 481 | static inline void* GetExistingThreadLocal(LocalStorageKey key) { |
| 482 | return GetThreadLocal(key); |
| 483 | } |
| 484 | #endif |
| 485 | |
| 486 | // A hint to the scheduler to let another thread run. |
| 487 | static void YieldCPU(); |
| 488 | |
| 489 | |
| 490 | // The thread name length is limited to 16 based on Linux's implementation of |
| 491 | // prctl(). |
| 492 | static const int kMaxThreadNameLength = 16; |
| 493 | |
| 494 | class PlatformData; |
| 495 | PlatformData* data() { return data_; } |
| 496 | |
| 497 | void NotifyStartedAndRun() { |
| 498 | if (start_semaphore_) start_semaphore_->Signal(); |
| 499 | Run(); |
| 500 | } |
| 501 | |
| 502 | private: |
| 503 | void set_name(const char* name); |
| 504 | |
| 505 | PlatformData* data_; |
| 506 | |
| 507 | char name_[kMaxThreadNameLength]; |
| 508 | int stack_size_; |
| 509 | Semaphore* start_semaphore_; |
| 510 | |
| 511 | DISALLOW_COPY_AND_ASSIGN(Thread); |
| 512 | }; |
| 513 | |
| 514 | } } // namespace v8::base |
| 515 | |
| 516 | #endif // V8_BASE_PLATFORM_PLATFORM_H_ |