Replace direct uses of __builtin_prefetch from SwissTable with the wrapper functions.
Add a new (internal) feature test macro to detect whether the wrappers are no-ops on a given platform.
Note that one-arg __builtin_prefetch(x) is equivalent to __builtin_prefetch(x, 0, 3), per `man BUILTIN_PREFETCH(3)` and gcc docs.
PiperOrigin-RevId: 449508660
Change-Id: I144e750205eec0c956d8dd62bc72e10bdb87c4f7
diff --git a/absl/base/internal/prefetch.h b/absl/base/internal/prefetch.h
index a71b389..d4971a6 100644
--- a/absl/base/internal/prefetch.h
+++ b/absl/base/internal/prefetch.h
@@ -72,6 +72,8 @@
#if ABSL_HAVE_BUILTIN(__builtin_prefetch) || defined(__GNUC__)
+#define ABSL_INTERNAL_HAVE_PREFETCH 1
+
// See __builtin_prefetch:
// https://gcc.gnu.org/onlinedocs/gcc/Other-Builtins.html.
//
diff --git a/absl/container/BUILD.bazel b/absl/container/BUILD.bazel
index d733cb2..9ef7066 100644
--- a/absl/container/BUILD.bazel
+++ b/absl/container/BUILD.bazel
@@ -589,6 +589,7 @@
"//absl/base:config",
"//absl/base:core_headers",
"//absl/base:endian",
+ "//absl/base:prefetch",
"//absl/memory",
"//absl/meta:type_traits",
"//absl/numeric:bits",
@@ -611,6 +612,7 @@
"//absl/base",
"//absl/base:config",
"//absl/base:core_headers",
+ "//absl/base:prefetch",
"//absl/base:raw_logging_internal",
"//absl/strings",
"@com_google_googletest//:gtest_main",
diff --git a/absl/container/CMakeLists.txt b/absl/container/CMakeLists.txt
index aad69fa..9b5c59a 100644
--- a/absl/container/CMakeLists.txt
+++ b/absl/container/CMakeLists.txt
@@ -681,6 +681,7 @@
absl::memory
absl::meta
absl::optional
+ absl::prefetch
absl::utility
absl::hashtablez_sampler
PUBLIC
@@ -702,6 +703,7 @@
absl::base
absl::config
absl::core_headers
+ absl::prefetch
absl::raw_logging_internal
absl::strings
GTest::gmock_main
diff --git a/absl/container/internal/raw_hash_set.h b/absl/container/internal/raw_hash_set.h
index 56251b2..769af50 100644
--- a/absl/container/internal/raw_hash_set.h
+++ b/absl/container/internal/raw_hash_set.h
@@ -197,6 +197,7 @@
#include "absl/base/config.h"
#include "absl/base/internal/endian.h"
+#include "absl/base/internal/prefetch.h"
#include "absl/base/optimization.h"
#include "absl/base/port.h"
#include "absl/container/internal/common.h"
@@ -1636,12 +1637,13 @@
template <class K = key_type>
void prefetch(const key_arg<K>& key) const {
(void)key;
-#if defined(__GNUC__)
+ // Avoid probing if we won't be able to prefetch the addresses received.
+#ifdef ABSL_INTERNAL_HAVE_PREFETCH
prefetch_heap_block();
auto seq = probe(ctrl_, hash_ref()(key), capacity_);
- __builtin_prefetch(static_cast<const void*>(ctrl_ + seq.offset()));
- __builtin_prefetch(static_cast<const void*>(slots_ + seq.offset()));
-#endif // __GNUC__
+ base_internal::PrefetchT0(ctrl_ + seq.offset());
+ base_internal::PrefetchT0(slots_ + seq.offset());
+#endif // ABSL_INTERNAL_HAVE_PREFETCH
}
// The API of find() has two extensions.
@@ -2159,9 +2161,7 @@
// This is intended to overlap with execution of calculating the hash for a
// key.
void prefetch_heap_block() const {
-#if defined(__GNUC__)
- __builtin_prefetch(static_cast<const void*>(ctrl_), 0, 1);
-#endif // __GNUC__
+ base_internal::PrefetchT2(ctrl_);
}
HashtablezInfoHandle& infoz() { return settings_.template get<1>(); }
diff --git a/absl/container/internal/raw_hash_set_test.cc b/absl/container/internal/raw_hash_set_test.cc
index 9cd88a2..914ec0c 100644
--- a/absl/container/internal/raw_hash_set_test.cc
+++ b/absl/container/internal/raw_hash_set_test.cc
@@ -31,6 +31,7 @@
#include "absl/base/attributes.h"
#include "absl/base/config.h"
#include "absl/base/internal/cycleclock.h"
+#include "absl/base/internal/prefetch.h"
#include "absl/base/internal/raw_logging.h"
#include "absl/container/internal/container_memory.h"
#include "absl/container/internal/hash_function_defaults.h"
