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Diffstat (limited to 'absl/flags/internal/flag.h')
-rw-r--r--absl/flags/internal/flag.h19
1 files changed, 13 insertions, 6 deletions
diff --git a/absl/flags/internal/flag.h b/absl/flags/internal/flag.h
index ef30a22f..b426ccb5 100644
--- a/absl/flags/internal/flag.h
+++ b/absl/flags/internal/flag.h
@@ -24,6 +24,7 @@
#include <string>
#include <type_traits>
+#include "absl/base/call_once.h"
#include "absl/base/config.h"
#include "absl/base/thread_annotations.h"
#include "absl/flags/config.h"
@@ -281,10 +282,8 @@ class FlagImpl {
help_(help.source),
help_source_kind_(static_cast<uint8_t>(help.kind)),
def_kind_(static_cast<uint8_t>(FlagDefaultKind::kGenFunc)),
- is_data_guard_inited_(false),
modified_(false),
on_command_line_(false),
- inited_(false),
counter_(0),
callback_(nullptr),
default_src_(default_value_gen),
@@ -406,20 +405,28 @@ class FlagImpl {
// Indicates if help message was supplied as literal or generator func.
const uint8_t help_source_kind_ : 1;
+ // ------------------------------------------------------------------------
+ // The bytes containing the const bitfields must not be shared with bytes
+ // containing the mutable bitfields.
+ // ------------------------------------------------------------------------
+
+ // Unique tag for absl::call_once call to initialize this flag.
+ //
+ // The placement of this variable between the immutable and mutable bitfields
+ // is important as prevents them from occupying the same byte. If you remove
+ // this variable, make sure to maintain this property.
+ absl::once_flag init_control_;
+
// Mutable flag's state (guarded by `data_guard_`).
// If def_kind_ == kDynamicValue, default_src_ holds a dynamically allocated
// value.
uint8_t def_kind_ : 1 ABSL_GUARDED_BY(*DataGuard());
- // Protects against multiple concurrent constructions of `data_guard_`.
- bool is_data_guard_inited_ : 1;
// Has this flag's value been modified?
bool modified_ : 1 ABSL_GUARDED_BY(*DataGuard());
// Has this flag been specified on command line.
bool on_command_line_ : 1 ABSL_GUARDED_BY(*DataGuard());
- // Indicates that the flag state is initialized.
- std::atomic<bool> inited_;
// Mutation counter
int64_t counter_ ABSL_GUARDED_BY(*DataGuard());
// Optional flag's callback and absl::Mutex to guard the invocations.