| // Copyright 2012 the V8 project authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| // Platform-specific code for Cygwin goes here. For the POSIX-compatible |
| // parts, the implementation is in platform-posix.cc. |
| |
| #include <errno.h> |
| #include <pthread.h> |
| #include <semaphore.h> |
| #include <stdarg.h> |
| #include <strings.h> // index |
| #include <sys/mman.h> // mmap & munmap |
| #include <sys/time.h> |
| #include <unistd.h> // sysconf |
| |
| #include <cmath> |
| |
| #undef MAP_TYPE |
| |
| #include "src/base/macros.h" |
| #include "src/base/platform/platform-posix.h" |
| #include "src/base/platform/platform.h" |
| #include "src/base/win32-headers.h" |
| |
| namespace v8 { |
| namespace base { |
| |
| namespace { |
| |
| // The memory allocation implementation is taken from platform-win32.cc. |
| |
| DWORD GetProtectionFromMemoryPermission(OS::MemoryPermission access) { |
| switch (access) { |
| case OS::MemoryPermission::kNoAccess: |
| case OS::MemoryPermission::kNoAccessWillJitLater: |
| return PAGE_NOACCESS; |
| case OS::MemoryPermission::kRead: |
| return PAGE_READONLY; |
| case OS::MemoryPermission::kReadWrite: |
| return PAGE_READWRITE; |
| case OS::MemoryPermission::kReadWriteExecute: |
| return PAGE_EXECUTE_READWRITE; |
| case OS::MemoryPermission::kReadExecute: |
| return PAGE_EXECUTE_READ; |
| } |
| UNREACHABLE(); |
| } |
| |
| uint8_t* RandomizedVirtualAlloc(size_t size, DWORD flags, DWORD protect, |
| void* hint) { |
| LPVOID base = nullptr; |
| |
| // For executable or reserved pages try to use the address hint. |
| if (protect != PAGE_READWRITE) { |
| base = VirtualAlloc(hint, size, flags, protect); |
| } |
| |
| // If that fails, let the OS find an address to use. |
| if (base == nullptr) { |
| base = VirtualAlloc(nullptr, size, flags, protect); |
| } |
| |
| return reinterpret_cast<uint8_t*>(base); |
| } |
| |
| } // namespace |
| |
| class CygwinTimezoneCache : public PosixTimezoneCache { |
| const char* LocalTimezone(double time) override; |
| |
| double LocalTimeOffset(double time_ms, bool is_utc) override; |
| |
| ~CygwinTimezoneCache() override {} |
| }; |
| |
| const char* CygwinTimezoneCache::LocalTimezone(double time) { |
| if (std::isnan(time)) return ""; |
| time_t tv = static_cast<time_t>(std::floor(time/msPerSecond)); |
| struct tm tm; |
| struct tm* t = localtime_r(&tv, &tm); |
| if (nullptr == t) return ""; |
| return tzname[0]; // The location of the timezone string on Cygwin. |
| } |
| |
| double LocalTimeOffset(double time_ms, bool is_utc) { |
| // On Cygwin, struct tm does not contain a tm_gmtoff field. |
| time_t utc = time(nullptr); |
| DCHECK_NE(utc, -1); |
| struct tm tm; |
| struct tm* loc = localtime_r(&utc, &tm); |
| DCHECK_NOT_NULL(loc); |
| // time - localtime includes any daylight savings offset, so subtract it. |
| return static_cast<double>((mktime(loc) - utc) * msPerSecond - |
| (loc->tm_isdst > 0 ? 3600 * msPerSecond : 0)); |
| } |
| |
| // static |
| void* OS::Allocate(void* hint, size_t size, size_t alignment, |
| MemoryPermission access) { |
| size_t page_size = AllocatePageSize(); |
| DCHECK_EQ(0, size % page_size); |
| DCHECK_EQ(0, alignment % page_size); |
| DCHECK_LE(page_size, alignment); |
| hint = AlignedAddress(hint, alignment); |
| |
| DWORD flags = (access == OS::MemoryPermission::kNoAccess) |
| ? MEM_RESERVE |
| : MEM_RESERVE | MEM_COMMIT; |
| DWORD protect = GetProtectionFromMemoryPermission(access); |
| |
| // First, try an exact size aligned allocation. |
| uint8_t* base = RandomizedVirtualAlloc(size, flags, protect, hint); |
| if (base == nullptr) return nullptr; // Can't allocate, we're OOM. |
| |
| // If address is suitably aligned, we're done. |
| uint8_t* aligned_base = RoundUp(base, alignment); |
| if (base == aligned_base) return reinterpret_cast<void*>(base); |
| |
| // Otherwise, free it and try a larger allocation. |
| CHECK(Free(base, size)); |
| |
| // Clear the hint. It's unlikely we can allocate at this address. |
| hint = nullptr; |
| |
| // Add the maximum misalignment so we are guaranteed an aligned base address |
| // in the allocated region. |
| size_t padded_size = size + (alignment - page_size); |
| const int kMaxAttempts = 3; |
| aligned_base = nullptr; |
| for (int i = 0; i < kMaxAttempts; ++i) { |
| base = RandomizedVirtualAlloc(padded_size, flags, protect, hint); |
| if (base == nullptr) return nullptr; // Can't allocate, we're OOM. |
| |
| // Try to trim the allocation by freeing the padded allocation and then |
| // calling VirtualAlloc at the aligned base. |
| CHECK(Free(base, padded_size)); |
| aligned_base = RoundUp(base, alignment); |
| base = reinterpret_cast<uint8_t*>( |
| VirtualAlloc(aligned_base, size, flags, protect)); |
| // We might not get the reduced allocation due to a race. In that case, |
| // base will be nullptr. |
| if (base != nullptr) break; |
| } |
| DCHECK_IMPLIES(base, base == aligned_base); |
| return reinterpret_cast<void*>(base); |
| } |
| |
| // static |
| bool OS::Free(void* address, const size_t size) { |
| DCHECK_EQ(0, static_cast<uintptr_t>(address) % AllocatePageSize()); |
| DCHECK_EQ(0, size % AllocatePageSize()); |
| USE(size); |
| return VirtualFree(address, 0, MEM_RELEASE) != 0; |
| } |
| |
| // static |
| bool OS::Release(void* address, size_t size) { |
| DCHECK_EQ(0, reinterpret_cast<uintptr_t>(address) % CommitPageSize()); |
| DCHECK_EQ(0, size % CommitPageSize()); |
| return VirtualFree(address, size, MEM_DECOMMIT) != 0; |
| } |
| |
| // static |
| bool OS::SetPermissions(void* address, size_t size, MemoryPermission access) { |
| DCHECK_EQ(0, reinterpret_cast<uintptr_t>(address) % CommitPageSize()); |
| DCHECK_EQ(0, size % CommitPageSize()); |
| if (access == MemoryPermission::kNoAccess) { |
| return VirtualFree(address, size, MEM_DECOMMIT) != 0; |
| } |
| DWORD protect = GetProtectionFromMemoryPermission(access); |
| return VirtualAlloc(address, size, MEM_COMMIT, protect) != nullptr; |
| } |
| |
| // static |
| bool OS::DiscardSystemPages(void* address, size_t size) { |
| // On Windows, discarded pages are not returned to the system immediately and |
| // not guaranteed to be zeroed when returned to the application. |
| using DiscardVirtualMemoryFunction = |
| DWORD(WINAPI*)(PVOID virtualAddress, SIZE_T size); |
| static std::atomic<DiscardVirtualMemoryFunction> discard_virtual_memory( |
| reinterpret_cast<DiscardVirtualMemoryFunction>(-1)); |
| if (discard_virtual_memory == |
| reinterpret_cast<DiscardVirtualMemoryFunction>(-1)) |
| discard_virtual_memory = |
| reinterpret_cast<DiscardVirtualMemoryFunction>(GetProcAddress( |
| GetModuleHandle(L"Kernel32.dll"), "DiscardVirtualMemory")); |
| // Use DiscardVirtualMemory when available because it releases faster than |
| // MEM_RESET. |
| DiscardVirtualMemoryFunction discard_function = discard_virtual_memory.load(); |
| if (discard_function) { |
| DWORD ret = discard_function(address, size); |
| if (!ret) return true; |
| } |
| // DiscardVirtualMemory is buggy in Win10 SP0, so fall back to MEM_RESET on |
| // failure. |
| void* ptr = VirtualAlloc(address, size, MEM_RESET, PAGE_READWRITE); |
| CHECK(ptr); |
| return ptr; |
| } |
| |
| // static |
| bool OS::HasLazyCommits() { |
| // TODO(alph): implement for the platform. |
| return false; |
| } |
| |
| std::vector<OS::SharedLibraryAddress> OS::GetSharedLibraryAddresses() { |
| std::vector<SharedLibraryAddresses> result; |
| // This function assumes that the layout of the file is as follows: |
| // hex_start_addr-hex_end_addr rwxp <unused data> [binary_file_name] |
| // If we encounter an unexpected situation we abort scanning further entries. |
| FILE* fp = fopen("/proc/self/maps", "r"); |
| if (fp == nullptr) return result; |
| |
| // Allocate enough room to be able to store a full file name. |
| const int kLibNameLen = FILENAME_MAX + 1; |
| char* lib_name = reinterpret_cast<char*>(malloc(kLibNameLen)); |
| |
| // This loop will terminate once the scanning hits an EOF. |
| while (true) { |
| uintptr_t start, end; |
| char attr_r, attr_w, attr_x, attr_p; |
| // Parse the addresses and permission bits at the beginning of the line. |
| if (fscanf(fp, "%" V8PRIxPTR "-%" V8PRIxPTR, &start, &end) != 2) break; |
| if (fscanf(fp, " %c%c%c%c", &attr_r, &attr_w, &attr_x, &attr_p) != 4) break; |
| |
| int c; |
| if (attr_r == 'r' && attr_w != 'w' && attr_x == 'x') { |
| // Found a read-only executable entry. Skip characters until we reach |
| // the beginning of the filename or the end of the line. |
| do { |
| c = getc(fp); |
| } while ((c != EOF) && (c != '\n') && (c != '/')); |
| if (c == EOF) break; // EOF: Was unexpected, just exit. |
| |
| // Process the filename if found. |
| if (c == '/') { |
| ungetc(c, fp); // Push the '/' back into the stream to be read below. |
| |
| // Read to the end of the line. Exit if the read fails. |
| if (fgets(lib_name, kLibNameLen, fp) == nullptr) break; |
| |
| // Drop the newline character read by fgets. We do not need to check |
| // for a zero-length string because we know that we at least read the |
| // '/' character. |
| lib_name[strlen(lib_name) - 1] = '\0'; |
| } else { |
| // No library name found, just record the raw address range. |
| snprintf(lib_name, kLibNameLen, |
| "%08" V8PRIxPTR "-%08" V8PRIxPTR, start, end); |
| } |
| result.push_back(SharedLibraryAddress(lib_name, start, end)); |
| } else { |
| // Entry not describing executable data. Skip to end of line to set up |
| // reading the next entry. |
| do { |
| c = getc(fp); |
| } while ((c != EOF) && (c != '\n')); |
| if (c == EOF) break; |
| } |
| } |
| free(lib_name); |
| fclose(fp); |
| return result; |
| } |
| |
| void OS::SignalCodeMovingGC() { |
| // Nothing to do on Cygwin. |
| } |
| |
| void OS::AdjustSchedulingParams() {} |
| |
| } // namespace base |
| } // namespace v8 |