llvm · SchrodingerZhu · Jun 14, 2024 · Jun 2, 2024 · Jun 2, 2024 · Jun 2, 2024
diff --git a/libc/config/config.json b/libc/config/config.json
@@ -49,6 +49,10 @@
     "LIBC_CONF_RAW_MUTEX_DEFAULT_SPIN_COUNT": {
       "value": 100,
       "doc": "Default number of spins before blocking if a mutex is in contention (default to 100)."
+    },
+    "LIBC_CONF_RWLOCK_DEFAULT_SPIN_COUNT": {
+      "value": 100,
+      "doc": "Default number of spins before blocking if a rwlock is in contention (default to 100)."
     }
   }
 }
diff --git a/libc/config/linux/aarch64/entrypoints.txt b/libc/config/linux/aarch64/entrypoints.txt
@@ -644,6 +644,15 @@ if(LLVM_LIBC_FULL_BUILD)
     libc.src.pthread.pthread_mutexattr_setrobust
     libc.src.pthread.pthread_mutexattr_settype
     libc.src.pthread.pthread_once
+    libc.src.pthread.pthread_rwlock_init
+    libc.src.pthread.pthread_rwlock_tryrdlock
+    libc.src.pthread.pthread_rwlock_rdlock
+    libc.src.pthread.pthread_rwlock_timedrdlock
+    libc.src.pthread.pthread_rwlock_trywrlock
+    libc.src.pthread.pthread_rwlock_wrlock
+    libc.src.pthread.pthread_rwlock_timedwrlock
+    libc.src.pthread.pthread_rwlock_unlock
+    libc.src.pthread.pthread_rwlock_destroy
     libc.src.pthread.pthread_rwlockattr_destroy
     libc.src.pthread.pthread_rwlockattr_getkind_np
     libc.src.pthread.pthread_rwlockattr_getpshared

diff --git a/libc/config/linux/api.td b/libc/config/linux/api.td
@@ -181,6 +181,7 @@ def PThreadAPI : PublicAPI<"pthread.h"> {
       "pthread_mutexattr_t",
       "pthread_once_t",
       "pthread_rwlockattr_t",
+      "pthread_rwlock_t",
       "pthread_t",
   ];
 }
@@ -270,6 +271,7 @@ def SysTypesAPI : PublicAPI<"sys/types.h"> {
     "pthread_mutexattr_t",
     "pthread_once_t",
     "pthread_rwlockattr_t",
+    "pthread_rwlock_t",
     "pthread_t",
     "size_t",
     "ssize_t",

diff --git a/libc/config/linux/x86_64/entrypoints.txt b/libc/config/linux/x86_64/entrypoints.txt
@@ -725,6 +725,15 @@ if(LLVM_LIBC_FULL_BUILD)
     libc.src.pthread.pthread_mutexattr_setrobust
     libc.src.pthread.pthread_mutexattr_settype
     libc.src.pthread.pthread_once
+    libc.src.pthread.pthread_rwlock_init
+    libc.src.pthread.pthread_rwlock_tryrdlock
+    libc.src.pthread.pthread_rwlock_rdlock
+    libc.src.pthread.pthread_rwlock_timedrdlock
+    libc.src.pthread.pthread_rwlock_trywrlock
+    libc.src.pthread.pthread_rwlock_wrlock
+    libc.src.pthread.pthread_rwlock_timedwrlock
+    libc.src.pthread.pthread_rwlock_unlock
+    libc.src.pthread.pthread_rwlock_destroy
     libc.src.pthread.pthread_rwlockattr_destroy
     libc.src.pthread.pthread_rwlockattr_getkind_np
     libc.src.pthread.pthread_rwlockattr_getpshared

diff --git a/libc/docs/configure.rst b/libc/docs/configure.rst
@@ -36,6 +36,7 @@ to learn about the defaults for your platform and target.
     - ``LIBC_CONF_PRINTF_FLOAT_TO_STR_USE_MEGA_LONG_DOUBLE_TABLE``: Use large table for better printf long double performance.
 * **"pthread" options**
     - ``LIBC_CONF_RAW_MUTEX_DEFAULT_SPIN_COUNT``: Default number of spins before blocking if a mutex is in contention (default to 100).
+    - ``LIBC_CONF_RWLOCK_DEFAULT_SPIN_COUNT``: Default number of spins before blocking if a rwlock is in contention (default to 100).
     - ``LIBC_CONF_TIMEOUT_ENSURE_MONOTONICITY``: Automatically adjust timeout to CLOCK_MONOTONIC (default to true). POSIX API may require CLOCK_REALTIME, which can be unstable and leading to unexpected behavior. This option will convert the real-time timestamp to monotonic timestamp relative to the time of call.
 * **"string" options**
     - ``LIBC_CONF_MEMSET_X86_USE_SOFTWARE_PREFETCHING``: Inserts prefetch for write instructions (PREFETCHW) for memset on x86 to recover performance when hardware prefetcher is disabled.

diff --git a/libc/include/CMakeLists.txt b/libc/include/CMakeLists.txt
@@ -332,6 +332,7 @@ add_gen_header(
     .llvm-libc-types.pthread_mutex_t
     .llvm-libc-types.pthread_mutexattr_t
     .llvm-libc-types.pthread_once_t
+    .llvm-libc-types.pthread_rwlock_t
     .llvm-libc-types.pthread_rwlockattr_t
     .llvm-libc-types.pthread_t
 )

diff --git a/libc/include/llvm-libc-types/CMakeLists.txt b/libc/include/llvm-libc-types/CMakeLists.txt
@@ -54,6 +54,7 @@ add_header(pthread_key_t HDR pthread_key_t.h)
 add_header(pthread_mutex_t HDR pthread_mutex_t.h DEPENDS .__futex_word .__mutex_type)
 add_header(pthread_mutexattr_t HDR pthread_mutexattr_t.h)
 add_header(pthread_once_t HDR pthread_once_t.h DEPENDS .__futex_word)
+add_header(pthread_rwlock_t HDR pthread_rwlock_t.h DEPENDS .__futex_word .pid_t)
 add_header(pthread_rwlockattr_t HDR pthread_rwlockattr_t.h)
 add_header(pthread_t HDR pthread_t.h DEPENDS .__thread_type)
 add_header(rlim_t HDR rlim_t.h)

diff --git a/libc/include/llvm-libc-types/pthread_rwlock_t.h b/libc/include/llvm-libc-types/pthread_rwlock_t.h
@@ -0,0 +1,26 @@
+//===-- Definition of pthread_mutex_t type --------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIBC_TYPES_PTHREAD_RWLOCK_T_H
+#define LLVM_LIBC_TYPES_PTHREAD_RWLOCK_T_H
+
+#include "llvm-libc-types/__futex_word.h"
+#include "llvm-libc-types/pid_t.h"
+typedef struct {
+  unsigned __is_pshared : 1;
+  unsigned __preference : 1;
+  int __state;
+  pid_t __writer_tid;
+  __futex_word __wait_queue_mutex;
+  __futex_word __pending_readers;
+  __futex_word __pending_writers;
+  __futex_word __reader_serialization;
+  __futex_word __writer_serialization;
+} pthread_rwlock_t;
+
+#endif // LLVM_LIBC_TYPES_PTHREAD_RWLOCK_T_H
diff --git a/libc/include/pthread.h.def b/libc/include/pthread.h.def
@@ -17,6 +17,7 @@
 #define PTHREAD_STACK_MIN (1 << 14) // 16KB
 
 #define PTHREAD_MUTEX_INITIALIZER {0}
+#define PTHREAD_RWLOCK_INITIALIZER {}
 #define PTHREAD_ONCE_INIT {0}
 
 enum {

diff --git a/libc/spec/posix.td b/libc/spec/posix.td
@@ -113,6 +113,8 @@ def POSIX : StandardSpec<"POSIX"> {
   NamedType PThreadRWLockAttrTType = NamedType<"pthread_rwlockattr_t">;
   PtrType PThreadRWLockAttrTPtr = PtrType<PThreadRWLockAttrTType>;
   ConstType ConstPThreadRWLockAttrTPtr = ConstType<PThreadRWLockAttrTPtr>;
+  RestrictedPtrType RestrictedPThreadRWLockAttrTPtr = RestrictedPtrType<PThreadRWLockAttrTType>;
+  ConstType ConstRestrictedPThreadRWLockAttrTPtr = ConstType<RestrictedPThreadRWLockAttrTPtr>;
 
   NamedType PThreadMutexAttrTType = NamedType<"pthread_mutexattr_t">;
   PtrType PThreadMutexAttrTPtr = PtrType<PThreadMutexAttrTType>;
@@ -126,6 +128,10 @@ def POSIX : StandardSpec<"POSIX"> {
   ConstType ConstPThreadMutexTPtr = ConstType<PThreadMutexTPtr>;
   ConstType ConstRestrictedPThreadMutexTPtr = ConstType<RestrictedPThreadMutexTPtr>;
 
+  NamedType PThreadRWLockTType = NamedType<"pthread_rwlock_t">;
+  PtrType PThreadRWLockTPtr = PtrType<PThreadRWLockTType>;
+  RestrictedPtrType RestrictedPThreadRWLockTPtr = RestrictedPtrType<PThreadRWLockTType>;
+
   PtrType PThreadTPtr = PtrType<PThreadTType>;
   RestrictedPtrType RestrictedPThreadTPtr = RestrictedPtrType<PThreadTType>;
 
@@ -1003,6 +1009,7 @@ def POSIX : StandardSpec<"POSIX"> {
         PThreadOnceCallback,
         PThreadOnceT,
         PThreadRWLockAttrTType,
+        PThreadRWLockTType,
         PThreadStartT,
         PThreadTSSDtorT,
         PThreadTType,
@@ -1259,6 +1266,51 @@ def POSIX : StandardSpec<"POSIX"> {
           RetValSpec<IntType>,
           [ArgSpec<PThreadRWLockAttrTPtr>, ArgSpec<IntType>]
       >,
+      FunctionSpec<
+        "pthread_rwlock_init",
+        RetValSpec<IntType>,
+        [ArgSpec<PThreadRWLockTPtr>, ArgSpec<ConstRestrictedPThreadRWLockAttrTPtr>]
+      >,
+      FunctionSpec<
+        "pthread_rwlock_tryrdlock",
+        RetValSpec<IntType>,
+        [ArgSpec<PThreadRWLockTPtr>]
+      >,
+      FunctionSpec<
+        "pthread_rwlock_trywrlock",
+        RetValSpec<IntType>,
+        [ArgSpec<PThreadRWLockTPtr>]
+      >,
+      FunctionSpec<
+        "pthread_rwlock_timedrdlock",
+        RetValSpec<IntType>,
+        [ArgSpec<RestrictedPThreadRWLockTPtr>, ArgSpec<ConstRestrictStructTimeSpecPtr>]
+      >,
+      FunctionSpec<
+        "pthread_rwlock_timedwrlock",
+        RetValSpec<IntType>,
+        [ArgSpec<RestrictedPThreadRWLockTPtr>, ArgSpec<ConstRestrictStructTimeSpecPtr>]
+      >,
+      FunctionSpec<
+        "pthread_rwlock_rdlock",
+        RetValSpec<IntType>,
+        [ArgSpec<PThreadRWLockTPtr>]
+      >,
+      FunctionSpec<
+        "pthread_rwlock_wrlock",
+        RetValSpec<IntType>,
+        [ArgSpec<PThreadRWLockTPtr>]
+      >,
+      FunctionSpec<
+        "pthread_rwlock_unlock",
+        RetValSpec<IntType>,
+        [ArgSpec<PThreadRWLockTPtr>]
+      >,
+      FunctionSpec<
+        "pthread_rwlock_destroy",
+        RetValSpec<IntType>,
+        [ArgSpec<PThreadRWLockTPtr>]
+      >,
     ]
   >;
 
@@ -1616,6 +1668,7 @@ def POSIX : StandardSpec<"POSIX"> {
       PThreadMutexTType,
       PThreadOnceT,
       PThreadRWLockAttrTType,
+      PThreadRWLockTType,
       PThreadTType,
       PidT,
       SSizeTType,

diff --git a/libc/spec/spec.td b/libc/spec/spec.td
@@ -126,6 +126,8 @@ def TimeTType : NamedType<"time_t">;
 def StructTimeSpec : NamedType<"struct timespec">;
 def StructTimeSpecPtr : PtrType<StructTimeSpec>;
 def ConstStructTimeSpecPtr : ConstType<StructTimeSpecPtr>;
+def RestrictStructTimeSpecPtr : RestrictedPtrType<StructTimeSpec>;
+def ConstRestrictStructTimeSpecPtr : ConstType<RestrictStructTimeSpecPtr>;
 
 def BSearchCompareT : NamedType<"__bsearchcompare_t">;
 def QSortCompareT : NamedType<"__qsortcompare_t">;

diff --git a/libc/src/__support/macros/attributes.h b/libc/src/__support/macros/attributes.h
@@ -42,4 +42,10 @@
 #define LIBC_CONSTINIT
 #endif
 
+#ifdef __clang__
+#define LIBC_PREFERED_TYPE(TYPE) [[clang::preferred_type(TYPE)]]
+#else
+#define LIBC_PREFERED_TYPE(TYPE)
+#endif
+
 #endif // LLVM_LIBC_SRC___SUPPORT_MACROS_ATTRIBUTES_H
diff --git a/libc/src/__support/threads/linux/CMakeLists.txt b/libc/src/__support/threads/linux/CMakeLists.txt
@@ -22,11 +22,11 @@ add_header_library(
     libc.src.__support.time.linux.abs_timeout
 )
 
-set(raw_mutex_additional_flags)
+set(monotonicity_flags)
 if (LIBC_CONF_TIMEOUT_ENSURE_MONOTONICITY)
-  set(raw_mutex_additional_flags -DLIBC_COPT_TIMEOUT_ENSURE_MONOTONICITY=1)
+  set(monotonicity_flags -DLIBC_COPT_TIMEOUT_ENSURE_MONOTONICITY=1)
 else()
-  set(raw_mutex_additional_flags -DLIBC_COPT_TIMEOUT_ENSURE_MONOTONICITY=0)
+  set(monotonicity_flags -DLIBC_COPT_TIMEOUT_ENSURE_MONOTONICITY=0)
 endif()
 
 add_header_library(
@@ -42,8 +42,22 @@ add_header_library(
     libc.hdr.types.pid_t
   COMPILE_OPTIONS
     -DLIBC_COPT_RAW_MUTEX_DEFAULT_SPIN_COUNT=${LIBC_CONF_RAW_MUTEX_DEFAULT_SPIN_COUNT}
-    ${raw_mutex_additional_flags}
-
+    ${monotonicity_flags}
+)
+
+add_header_library(
+  rwlock
+  HDRS
+    rwlock.h
+  DEPENDS
+    .futex_utils
+    .raw_mutex
+    libc.src.__support.common
+    libc.src.__support.OSUtil.osutil
+    libc.src.__support.CPP.limits
+  COMPILE_OPTIONS
+    -DLIBC_COPT_RWLOCK_DEFAULT_SPIN_COUNT=${LIBC_CONF_RWLOCK_DEFAULT_SPIN_COUNT}
+    ${monotonicity_flags}
 )
 
 add_header_library(