platform.cc

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#if defined(__APPLE__)
#include <pthread.h>
#include <sys/mman.h>
 
#include <format>
#include <print>
#include <utility>
 
#include "src/platform/platform-base.h"
 
namespace broom {
namespace platform {
constexpr const int kInvalidFd = -1;
 
void* GetStackBottom() { return pthread_get_stackaddr_np(pthread_self()); }
 
void UnmapMemorySpace(const MemorySpace& space) {
  BENSURE_EQ(munmap(space.StartPtr(), space.Size()), 0,
             "Failed to unmap memory: {}", strerror(errno));
}
 
int GetProtectionFromMemoryPermissions(MemoryPermissions permissions) {
  switch (permissions) {
    case MemoryPermissions::kReadOnly:
      return PROT_READ;
    case MemoryPermissions::kWriteOnly:
      return PROT_WRITE;
    case MemoryPermissions::kReadWrite:
      return PROT_READ | PROT_WRITE;
    case MemoryPermissions::kNone:
      return 0;
  }
  ABORT("Unexpected permissions");
}
 
int GetFlagsFromMemoryPermissions(BROOM_UNUSED MemoryPermissions permissions) {
  return 0;
}
 
MemorySpace MapMemorySpace(size_t space_size, MemoryPermissions permissions) {
  int prot = GetProtectionFromMemoryPermissions(permissions);
  int flags = GetFlagsFromMemoryPermissions(permissions);
  flags |= MAP_ANON;
  flags |= MAP_PRIVATE;
  void* maybe_pointer = mmap(nullptr, space_size, prot, flags, kInvalidFd, 0);
  BASSERT_NE(maybe_pointer, nullptr, "Unrecoverable mmap failure: {}",
             strerror(errno));
  return MemorySpace{maybe_pointer, space_size};
}
 
}  // namespace platform
}  // namespace broom
#endif