dart::BSS Class Reference

#include <bss_relocs.h>

Inheritance diagram for dart::BSS:

Public Types
enum class	Relocation : intptr_t { DRT_GetFfiCallbackMetadata , DRT_ExitTemporaryIsolate , EndOfVmEntries , EndOfIsolateGroupEntries = EndOfVmEntries }

Static Public Member Functions
static constexpr intptr_t	RelocationIndex (Relocation reloc)
static void	Initialize (Thread *current, uword *bss, bool vm)
static void	InitializeBSSEntry (BSS::Relocation relocation, uword new_value, uword *bss_start)

Static Public Attributes
static constexpr intptr_t	kVmEntryCount
static constexpr intptr_t	kIsolateGroupEntryCount

Detailed Description

Definition at line 13 of file bss_relocs.h.

Member Enumeration Documentation

Relocation

enum class dart::BSS::Relocation : intptr_t

strong

Enumerator
DRT_GetFfiCallbackMetadata
DRT_ExitTemporaryIsolate
EndOfVmEntries
EndOfIsolateGroupEntries

Definition at line 18 of file bss_relocs.h.

                        : intptr_t {
    DRT_GetFfiCallbackMetadata,  // TODO(https://dartbug.com/52579): Remove.
    DRT_ExitTemporaryIsolate,    // TODO(https://dartbug.com/52579): Remove.
    EndOfVmEntries,
 
    // We don't have any isolate group specific entries at the moment.
    EndOfIsolateGroupEntries = EndOfVmEntries,
  };

Member Function Documentation

Initialize()

void dart::BSS::Initialize ( Thread *  current, uword *  bss, bool  vm  )

static

Definition at line 30 of file bss_relocs.cc.

                                                               {
  // TODO(https://dartbug.com/52579): Remove.
  InitializeBSSEntry(Relocation::DRT_GetFfiCallbackMetadata,
                     reinterpret_cast<uword>(DLRT_GetFfiCallbackMetadata),
                     bss_start);
  InitializeBSSEntry(Relocation::DRT_ExitTemporaryIsolate,
                     reinterpret_cast<uword>(DLRT_ExitTemporaryIsolate),
                     bss_start);
}

InitializeBSSEntry()

void dart::BSS::InitializeBSSEntry ( BSS::Relocation  relocation, uword  new_value, uword *  bss_start  )

static

Definition at line 12 of file bss_relocs.cc.

                                               {
  std::atomic<uword>* slot = reinterpret_cast<std::atomic<uword>*>(
      &bss_start[BSS::RelocationIndex(relocation)]);
  uword old_value = slot->load(std::memory_order_relaxed);
  // FullSnapshotReader::ReadProgramSnapshot, and thus BSS::Initialize, can
  // get called multiple times for the same isolate in different threads, though
  // the initialized value will be consistent and thus change only once. Avoid
  // calling compare_exchange_strong unless we actually need to change the
  // value, to avoid spurious read/write races by TSAN.
  if (old_value == new_value) return;
  if (!slot->compare_exchange_strong(old_value, new_value,
                                     std::memory_order_relaxed)) {
    RELEASE_ASSERT(old_value == new_value);
  }
}

RelocationIndex()

static constexpr intptr_t dart::BSS::RelocationIndex ( Relocation  reloc )

inlinestaticconstexpr

Definition at line 33 of file bss_relocs.h.

                                                              {
    return static_cast<intptr_t>(reloc);
  }

Member Data Documentation

kIsolateGroupEntryCount

constexpr intptr_t dart::BSS::kIsolateGroupEntryCount

staticconstexpr

Initial value:

=
      static_cast<intptr_t>(Relocation::EndOfIsolateGroupEntries)

Definition at line 30 of file bss_relocs.h.

kVmEntryCount

constexpr intptr_t dart::BSS::kVmEntryCount

staticconstexpr

Initial value:

=
      static_cast<intptr_t>(Relocation::EndOfVmEntries)

Definition at line 27 of file bss_relocs.h.

---

The documentation for this class was generated from the following files:

• third_party/dart-lang/sdk/runtime/vm/bss_relocs.h
• third_party/dart-lang/sdk/runtime/vm/bss_relocs.cc