Export of internal Abseil changes

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341670bce317dd6af8d3c066970230591a47e80c by Martijn Vels <mvels@google.com>:

Change GetStack() and GetParentStack() to return absl::Span

PiperOrigin-RevId: 368765721

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6aaab9536d6957303c7aba100c3afaa6fb0ea2c8 by Martijn Vels <mvels@google.com>:

Remove locking from parent stack.

This change removes the need to lock all access to `parent_stack' by making the 'copy constructor' logic specify the 'copied from' CordzInfo (where available) to the TrackCord function, after which parent_stack is immutable.

PiperOrigin-RevId: 368760630

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b19e2059cada35a8ede994833018edac94de6ddc by Martijn Vels <mvels@google.com>:

Add cordz instrumentation to Cord

PiperOrigin-RevId: 368746225

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67b8bbf980f0f4e1db79aa32968e9a715a09b51a by Martijn Vels <mvels@google.com>:

Create ABSL_INTERNAL_CORDZ_ENABLED define controlling when Cordz code is enabled

There are specific builds and condtions under which we don't support cordz sampling, which is per this change represented by ABSL_INTERNAL_CORDZ_ENABLED being defined.

PiperOrigin-RevId: 368731603

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8cbfe0e3169637a620f4b66ad2bc2ce340879cb0 by Martijn Vels <mvels@google.com>:

Add a `rep` property to CordzInfo to be managed by Cord logic.

This change adds a `rep` property to CordzInfo, which is intended to be used by collection logic.

Mini design:
Cord invokes TrackCord() providing the active 'root' cordrep of the newly sampled Cord, returning a CordzInfo with a weak (uncounted) reference to this root. Cord invokes `SetCordRep()` each time the root cordrep of the sampled Cord is updated while holding `mutex()`. Cord must also obtain `mutex()` _before_ removing a reference on the old root. i.e.: Cord must guarantee that the (weak) reference held in CordzInfo is at all times valid.

CordzInfo collection code can then safely obtain a (reference counted) rep pointer by adding a reference to `rep_` while holding `mutex()`. This requires only a very brief critical section inside CordzInfo logic, minimizing contention with concurrent Cord updates.

Cord code should typically obtain and hold `mutex()` for the entirety of each mutating Cord operation on a sampled cord. As Cord is thread compatible, it never competes on the lock with any other thread. The only possible concurrent access is from Cordz collection code, which should be a relatively rare event.

PiperOrigin-RevId: 368673758

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1255120dce2bdd6b4205a34a0e555e0b74b6152f by Martijn Vels <mvels@google.com>:

Remove 'depth' from active recorded metrics.

Going forward we do not 'live' record depth (and size), but will observe these at collection time only.

PiperOrigin-RevId: 368636572

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83e5146e35f221736b49e9f0a8805f8c159a51db by Martijn Vels <mvels@google.com>:

Make cordz targets visible in OSS

PiperOrigin-RevId: 368615010

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dcb16a4f1239151f0a8c70a8cfeb29dabbd113b8 by Martijn Vels <mvels@google.com>:

Internal cleanup

PiperOrigin-RevId: 368514666
GitOrigin-RevId: 341670bce317dd6af8d3c066970230591a47e80c
Change-Id: I94cecfbbd441eb386f99fc5186c468a7a5538862

1 files changed, 149 insertions, 1 deletions

diff --git a/absl/strings/CMakeLists.txt b/absl/strings/CMakeLists.txt
index 0d93d5ff..044e38b3 100644
--- a/absl/strings/CMakeLists.txt
+++ b/absl/strings/CMakeLists.txt
@@ -259,7 +259,7 @@ absl_cc_test(
 absl_cc_test(
   NAME
     str_join_test
-  SRCS
+ss  SRCS
     "str_join_test.cc"
   COPTS
     ${ABSL_TEST_COPTS}
@@ -605,6 +605,152 @@ absl_cc_test(
 
 absl_cc_library(
   NAME
+    cordz_functions
+  HDRS
+    "internal/cordz_functions.h"
+  SRCS
+    "internal/cordz_functions.cc"
+  COPTS
+    ${ABSL_DEFAULT_COPTS}
+  DEPS
+    absl::config
+    absl::core_headers
+    absl::exponential_biased
+    absl::raw_logging_internal
+)
+
+absl_cc_test(
+  NAME
+    cordz_functions_test
+  SRCS
+    "internal/cordz_functions_test.cc"
+  DEPS
+    absl::config
+    absl::cord_test_helpers
+    absl::cordz_functions
+    gmock_main
+)
+
+absl_cc_library(
+  NAME
+    cordz_statistics
+  HDRS
+    "internal/cordz_statistics.h"
+  COPTS
+    ${ABSL_DEFAULT_COPTS}
+  DEPS
+    absl::config
+    absl::core_headers
+    absl::synchronization
+)
+
+absl_cc_library(
+  NAME
+    cordz_handle
+  HDRS
+    "internal/cordz_handle.h"
+  SRCS
+    "internal/cordz_handle.cc"
+  COPTS
+    ${ABSL_DEFAULT_COPTS}
+  DEPS
+    absl::config
+    absl::synchronization
+)
+
+absl_cc_test(
+  NAME
+    cordz_handle_test
+  SRCS
+    "internal/cordz_handle_test.cc"
+  DEPS
+    absl::config
+    absl::cord_test_helpers
+    absl::cordz_handle
+    absl::memory
+    absl::random_random
+    absl::random_distributions
+    absl::synchronization
+    absl::time
+    gmock_main
+)
+
+absl_cc_library(
+  NAME
+    cordz_info
+  HDRS
+    "internal/cordz_info.h"
+  SRCS
+    "internal/cordz_info.cc"
+  COPTS
+    ${ABSL_DEFAULT_COPTS}
+  DEPS
+    absl::config
+    absl::cord_internal
+    absl::cordz_handle
+    absl::cordz_statistics
+    absl::core_headers
+    absl::span
+    absl::stacktrace
+    absl::synchronization
+)
+
+absl_cc_test(
+  NAME
+    cordz_info_test
+  SRCS
+    "internal/cordz_info_test.cc"
+  DEPS
+    absl::config
+    absl::cord_internal
+    absl::cord_test_helpers
+    absl::cordz_handle
+    absl::cordz_info
+    absl::span
+    absl::stacktrace
+    absl::symbolize
+    gmock_main
+)
+
+absl_cc_library(
+  NAME
+    cordz_sample_token
+  HDRS
+    "internal/cordz_sample_token.h"
+  SRCS
+    "internal/cordz_sample_token.cc"
+  COPTS
+    ${ABSL_DEFAULT_COPTS}
+  DEPS
+    absl::config
+    absl::cordz_handle
+    absl::cordz_info
+)
+
+absl_cc_test(
+  NAME
+    cordz_sample_token_test
+  SRCS
+    "internal/cordz_sample_token_test.cc"
+  COPTS
+    ${ABSL_DEFAULT_COPTS}
+  DEPS
+    absl::config
+    absl::cord_internal
+    absl::cordz_handle
+    absl::cordz_info
+    absl::cordz_info
+    absl::cordz_sample_token
+    absl::memory
+    absl::random_random
+    absl::synchronization
+    absl::thread_pool
+    absl::time
+    gmock_main
+)
+
+absl_cc_library(
+  NAME
     cord
   HDRS
     "cord.h"
@@ -616,6 +762,8 @@ absl_cc_library(
     absl::base
     absl::config
     absl::cord_internal
+    absl::cordz_functions
+    absl::cordz_info
     absl::cordz_update_tracker
     absl::core_headers
     absl::endian