[libc] Add pthread_mutexattr_t type and its setters and getters.

A simple implementation of the getters and setters has been added. More
logic can be added to them in future as required.

Reviewed By: michaelrj

Differential Revision: https://reviews.llvm.org/D122969

31 files changed, 783 insertions, 0 deletions

diff --git a/libc/config/linux/aarch64/entrypoints.txt b/libc/config/linux/aarch64/entrypoints.txt
index 72919c1b81e4..aa66c0d040a4 100644
--- a/libc/config/linux/aarch64/entrypoints.txt
+++ b/libc/config/linux/aarch64/entrypoints.txt
@@ -228,6 +228,16 @@ if(LLVM_LIBC_FULL_BUILD)
     libc.src.threads.mtx_unlock
     libc.src.threads.thrd_create
     libc.src.threads.thrd_join
+
+    # pthread.h entrypoints
+    libc.src.pthread.pthread_mutexattr_destroy
+    libc.src.pthread.pthread_mutexattr_init
+    libc.src.pthread.pthread_mutexattr_getpshared
+    libc.src.pthread.pthread_mutexattr_getrobust
+    libc.src.pthread.pthread_mutexattr_gettype
+    libc.src.pthread.pthread_mutexattr_setpshared
+    libc.src.pthread.pthread_mutexattr_setrobust
+    libc.src.pthread.pthread_mutexattr_settype
   )
 endif()
 
diff --git a/libc/config/linux/api.td b/libc/config/linux/api.td
index b351ea6d5e29..9d2f142ef43a 100644
--- a/libc/config/linux/api.td
+++ b/libc/config/linux/api.td
@@ -237,6 +237,10 @@ def ThreadsAPI : PublicAPI<"threads.h"> {
   ];
 }
 
+def PThreadAPI : PublicAPI<"pthread.h"> {
+  let Types = ["pthread_mutexattr_t"];
+}
+
 def UniStdAPI : PublicAPI<"unistd.h"> {
   let Types = ["off_t", "size_t", "ssize_t"];
 }
diff --git a/libc/config/linux/x86_64/entrypoints.txt b/libc/config/linux/x86_64/entrypoints.txt
index 5aa64a8dc7df..c5c5e5046de2 100644
--- a/libc/config/linux/x86_64/entrypoints.txt
+++ b/libc/config/linux/x86_64/entrypoints.txt
@@ -222,6 +222,16 @@ if(LLVM_LIBC_FULL_BUILD)
     # assert.h entrypoints
     # libc.src.assert.__assert_fail
 
+    # pthread.h entrypoints
+    libc.src.pthread.pthread_mutexattr_destroy
+    libc.src.pthread.pthread_mutexattr_init
+    libc.src.pthread.pthread_mutexattr_getpshared
+    libc.src.pthread.pthread_mutexattr_getrobust
+    libc.src.pthread.pthread_mutexattr_gettype
+    libc.src.pthread.pthread_mutexattr_setpshared
+    libc.src.pthread.pthread_mutexattr_setrobust
+    libc.src.pthread.pthread_mutexattr_settype
+
     # stdlib.h entrypoints
     libc.src.stdlib._Exit
     # libc.src.stdlib.abort
diff --git a/libc/include/CMakeLists.txt b/libc/include/CMakeLists.txt
index 30e188878eac..efe9e8107ee7 100644
--- a/libc/include/CMakeLists.txt
+++ b/libc/include/CMakeLists.txt
@@ -155,6 +155,15 @@ add_gen_header(
     .llvm-libc-types.ssize_t
 )
 
+add_gen_header(
+  pthread
+  DEF_FILE pthread.h.def
+  GEN_HDR pthread.h
+  DEPENDS
+    .llvm_libc_common_h
+    .llvm-libc-types.pthread_mutexattr_t
+)
+
 # TODO: Not all platforms will have a include/sys directory. Add the sys
 # directory and the targets for sys/*.h files conditional to the OS requiring
 # them.
diff --git a/libc/include/llvm-libc-types/CMakeLists.txt b/libc/include/llvm-libc-types/CMakeLists.txt
index 8fb859d94156..77a86fe25619 100644
--- a/libc/include/llvm-libc-types/CMakeLists.txt
+++ b/libc/include/llvm-libc-types/CMakeLists.txt
@@ -18,6 +18,7 @@ add_header(mode_t HDR mode_t.h)
 add_header(mtx_t HDR mtx_t.h DEPENDS .__futex_word .__mutex_type)
 add_header(off_t HDR off_t.h)
 add_header(once_flag HDR once_flag.h DEPENDS .__futex_word)
+add_header(pthread_mutexattr_t HDR pthread_mutexattr_t.h)
 add_header(size_t HDR size_t.h)
 add_header(ssize_t HDR ssize_t.h)
 add_header(struct_sigaction HDR struct_sigaction.h)
diff --git a/libc/include/llvm-libc-types/pthread_mutexattr_t.h b/libc/include/llvm-libc-types/pthread_mutexattr_t.h
new file mode 100644
index 000000000000..be1ff5611ed4
--- /dev/null
+++ b/libc/include/llvm-libc-types/pthread_mutexattr_t.h
@@ -0,0 +1,16 @@
+//===-- Definition of pthread_mutexattr_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_MUTEXATTR_T_H
+#define __LLVM_LIBC_TYPES_PTHREAD_MUTEXATTR_T_H
+
+// pthread_mutexattr_t is a collection bit mapped flags. The mapping is internal
+// detail of the libc implementation.
+typedef unsigned int pthread_mutexattr_t;
+
+#endif // __LLVM_LIBC_TYPES_PTHREAD_MUTEXATTR_T_H
diff --git a/libc/include/pthread.h.def b/libc/include/pthread.h.def
new file mode 100644
index 000000000000..9de3da4b5dee
--- /dev/null
+++ b/libc/include/pthread.h.def
@@ -0,0 +1,29 @@
+//===-- POSIX header pthread.h --------------------------------------------===//
+//
+// 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_PTHREAD_H
+#define LLVM_LIBC_PTHREAD_H
+
+#include <__llvm-libc-common.h>
+
+enum {
+  PTHREAD_MUTEX_NORMAL = 0x0,
+  PTHREAD_MUTEX_ERRORCHECK = 0x1,
+  PTHREAD_MUTEX_RECURSIVE = 0x2,
+  PTHREAD_MUTEX_DEFAULT = PTHREAD_MUTEX_NORMAL,
+
+  PTHREAD_PROCESS_PRIVATE = 0x0,
+  PTHREAD_PROCESS_SHARED = 0x1,
+
+  PTHREAD_MUTEX_STALLED = 0x0,
+  PTHREAD_MUTEX_ROBUST = 0x1,
+};
+
+%%public_api()
+
+#endif // LLVM_LIBC_PTHREAD_H
diff --git a/libc/spec/posix.td b/libc/spec/posix.td
index b9641d8c362d..882ccf5e6d72 100644
--- a/libc/spec/posix.td
+++ b/libc/spec/posix.td
@@ -20,6 +20,11 @@ def POSIX : StandardSpec<"POSIX"> {
   NamedType ModeTType = NamedType<"mode_t">;
   NamedType OffTType = NamedType<"off_t">;
   NamedType SSizeTType = NamedType<"ssize_t">;
+  NamedType PThreadMutexAttrTType = NamedType<"pthread_mutexattr_t">;
+  PtrType PThreadMutexAttrTPtr = PtrType<PThreadMutexAttrTType>;
+  RestrictedPtrType RestrictedPThreadMutexAttrTPtr = RestrictedPtrType<PThreadMutexAttrTType>;
+  ConstType ConstPThreadMutexAttrTPtr = ConstType<PThreadMutexAttrTPtr>;
+  ConstType ConstRestrictedPThreadMutexAttrTPtr = ConstType<RestrictedPThreadMutexAttrTPtr>;
 
   HeaderSpec Errno = HeaderSpec<
       "errno.h",
@@ -371,10 +376,80 @@ def POSIX : StandardSpec<"POSIX"> {
     ]
   >;
 
+  HeaderSpec PThread = HeaderSpec<
+    "pthread.h",
+    [], // Macros
+    [PThreadMutexAttrTType], // Types
+    [], // Enumerations
+    [
+      FunctionSpec<
+          "pthread_mutexattr_init",
+          RetValSpec<IntType>,
+          [ArgSpec<PThreadMutexAttrTPtr>]
+      >,
+      FunctionSpec<
+          "pthread_mutexattr_destroy",
+          RetValSpec<IntType>,
+          [ArgSpec<PThreadMutexAttrTPtr>]
+      >,
+      FunctionSpec<
+          "pthread_mutexattr_gettype",
+          RetValSpec<IntType>,
+          [ArgSpec<ConstRestrictedPThreadMutexAttrTPtr>, ArgSpec<RestrictedIntPtr>]
+      >,
+      FunctionSpec<
+          "pthread_mutexattr_settype",
+          RetValSpec<IntType>,
+          [ArgSpec<RestrictedPThreadMutexAttrTPtr>, ArgSpec<IntType>]
+      >,
+      FunctionSpec<
+          "pthread_mutexattr_getrobust",
+          RetValSpec<IntType>,
+          [ArgSpec<ConstRestrictedPThreadMutexAttrTPtr>, ArgSpec<RestrictedIntPtr>]
+      >,
+      FunctionSpec<
+          "pthread_mutexattr_setrobust",
+          RetValSpec<IntType>,
+          [ArgSpec<RestrictedPThreadMutexAttrTPtr>, ArgSpec<IntType>]
+      >,
+      FunctionSpec<
+          "pthread_mutexattr_getpshared",
+          RetValSpec<IntType>,
+          [ArgSpec<ConstRestrictedPThreadMutexAttrTPtr>, ArgSpec<RestrictedIntPtr>]
+      >,
+      FunctionSpec<
+          "pthread_mutexattr_setpshared",
+          RetValSpec<IntType>,
+          [ArgSpec<RestrictedPThreadMutexAttrTPtr>, ArgSpec<IntType>]
+      >,
+      FunctionSpec<
+          "pthread_mutexattr_getprotocol",
+          RetValSpec<IntType>,
+          [ArgSpec<ConstRestrictedPThreadMutexAttrTPtr>, ArgSpec<RestrictedIntPtr>]
+      >,
+      FunctionSpec<
+          "pthread_mutexattr_setprotocol",
+          RetValSpec<IntType>,
+          [ArgSpec<RestrictedPThreadMutexAttrTPtr>, ArgSpec<IntType>]
+      >,
+      FunctionSpec<
+          "pthread_mutexattr_getprioceiling",
+          RetValSpec<IntType>,
+          [ArgSpec<ConstRestrictedPThreadMutexAttrTPtr>, ArgSpec<RestrictedIntPtr>]
+      >,
+      FunctionSpec<
+          "pthread_mutexattr_setprioceiling",
+          RetValSpec<IntType>,
+          [ArgSpec<RestrictedPThreadMutexAttrTPtr>, ArgSpec<IntType>]
+      >,
+    ]
+  >;
+
   let Headers = [
     CType,
     Errno,
     FCntl,
+    PThread,
     Signal,
     StdLib,
     SysMMan,
diff --git a/libc/spec/spec.td b/libc/spec/spec.td
index 183e1b7d0ecc..2261043a726c 100644
--- a/libc/spec/spec.td
+++ b/libc/spec/spec.td
@@ -84,6 +84,7 @@ def ThrdTType : NamedType<"thrd_t">;
 def ThrdTTypePtr : PtrType<ThrdTType>;
 
 def IntPtr : PtrType<IntType>;
+def RestrictedIntPtr : RestrictedPtrType<IntType>;
 def FloatPtr : PtrType<FloatType>;
 def DoublePtr : PtrType<DoubleType>;
 
diff --git a/libc/src/CMakeLists.txt b/libc/src/CMakeLists.txt
index f16af6c94fc7..a53e382fcaeb 100644
--- a/libc/src/CMakeLists.txt
+++ b/libc/src/CMakeLists.txt
@@ -10,6 +10,7 @@ add_subdirectory(stdlib)
 
 if(${LIBC_TARGET_OS} STREQUAL "linux")
   add_subdirectory(fcntl)
+  add_subdirectory(pthread)
   add_subdirectory(sys)
   add_subdirectory(unistd)
 endif()
diff --git a/libc/src/pthread/CMakeLists.txt b/libc/src/pthread/CMakeLists.txt
new file mode 100644
index 000000000000..22d61c85af27
--- /dev/null
+++ b/libc/src/pthread/CMakeLists.txt
@@ -0,0 +1,98 @@
+add_header_library(
+  pthread_mutexattr
+  HDRS
+    pthread_mutexattr.h
+  DEPENDS
+    libc.include.pthread
+)
+
+add_entrypoint_object(
+  pthread_mutexattr_init
+  SRCS
+    pthread_mutexattr_init.cpp
+  HDRS
+    pthread_mutexattr_init.h
+  DEPENDS
+    .pthread_mutexattr
+    libc.include.pthread
+)
+
+add_entrypoint_object(
+  pthread_mutexattr_gettype
+  SRCS
+    pthread_mutexattr_gettype.cpp
+  HDRS
+    pthread_mutexattr_gettype.h
+  DEPENDS
+    .pthread_mutexattr
+    libc.include.pthread
+)
+
+add_entrypoint_object(
+  pthread_mutexattr_settype
+  SRCS
+    pthread_mutexattr_settype.cpp
+  HDRS
+    pthread_mutexattr_settype.h
+  DEPENDS
+    .pthread_mutexattr
+    libc.include.pthread
+)
+
+add_entrypoint_object(
+  pthread_mutexattr_destroy
+  SRCS
+    pthread_mutexattr_destroy.cpp
+  HDRS
+    pthread_mutexattr_destroy.h
+  DEPENDS
+    .pthread_mutexattr
+    libc.include.errno
+    libc.include.pthread
+)
+
+add_entrypoint_object(
+  pthread_mutexattr_getrobust
+  SRCS
+    pthread_mutexattr_getrobust.cpp
+  HDRS
+    pthread_mutexattr_getrobust.h
+  DEPENDS
+    .pthread_mutexattr
+    libc.include.pthread
+)
+
+add_entrypoint_object(
+  pthread_mutexattr_setrobust
+  SRCS
+    pthread_mutexattr_setrobust.cpp
+  HDRS
+    pthread_mutexattr_setrobust.h
+  DEPENDS
+    .pthread_mutexattr
+    libc.include.errno
+    libc.include.pthread
+)
+
+add_entrypoint_object(
+  pthread_mutexattr_getpshared
+  SRCS
+    pthread_mutexattr_getpshared.cpp
+  HDRS
+    pthread_mutexattr_getpshared.h
+  DEPENDS
+    .pthread_mutexattr
+    libc.include.pthread
+)
+
+add_entrypoint_object(
+  pthread_mutexattr_setpshared
+  SRCS
+    pthread_mutexattr_setpshared.cpp
+  HDRS
+    pthread_mutexattr_setpshared.h
+  DEPENDS
+    .pthread_mutexattr
+    libc.include.errno
+    libc.include.pthread
+)
diff --git a/libc/src/pthread/pthread_mutexattr.h b/libc/src/pthread/pthread_mutexattr.h
new file mode 100644
index 000000000000..4f969e288c88
--- /dev/null
+++ b/libc/src/pthread/pthread_mutexattr.h
@@ -0,0 +1,36 @@
+//===-- Declarations related mutex attribute objects  -----------*- C++ -*-===//
+//
+// 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_SRC_PTHREAD_PTHREAD_MUTEXATTR_H
+#define LLVM_LIBC_SRC_PTHREAD_PTHREAD_MUTEXATTR_H
+
+#include <pthread.h>
+
+namespace __llvm_libc {
+
+enum class PThreadMutexAttrPos : unsigned int {
+  TYPE_SHIFT = 0,
+  TYPE_MASK = 0x3 << TYPE_SHIFT, // Type is encoded in 2 bits
+
+  ROBUST_SHIFT = 2,
+  ROBUST_MASK = 0x1 << ROBUST_SHIFT,
+
+  PSHARED_SHIFT = 3,
+  PSHARED_MASK = 0x1 << PSHARED_SHIFT,
+
+  // TODO: Add a mask for protocol and prioceiling when it is supported.
+};
+
+constexpr pthread_mutexattr_t DEFAULT_MUTEXATTR =
+    PTHREAD_MUTEX_DEFAULT << unsigned(PThreadMutexAttrPos::TYPE_SHIFT) |
+    PTHREAD_MUTEX_STALLED << unsigned(PThreadMutexAttrPos::ROBUST_SHIFT) |
+    PTHREAD_PROCESS_PRIVATE << unsigned(PThreadMutexAttrPos::PSHARED_SHIFT);
+
+} // namespace __llvm_libc
+
+#endif // LLVM_LIBC_SRC_PTHREAD_PTHREAD_MUTEXATTR_H
diff --git a/libc/src/pthread/pthread_mutexattr_destroy.cpp b/libc/src/pthread/pthread_mutexattr_destroy.cpp
new file mode 100644
index 000000000000..ed338b4e0760
--- /dev/null
+++ b/libc/src/pthread/pthread_mutexattr_destroy.cpp
@@ -0,0 +1,23 @@
+//===-- Implementation of the pthread_mutexattr_init ----------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#include "pthread_mutexattr_destroy.h"
+#include "pthread_mutexattr.h"
+
+#include "src/__support/common.h"
+
+#include <errno.h>
+
+namespace __llvm_libc {
+
+LLVM_LIBC_FUNCTION(int, pthread_mutexattr_destroy,
+                   (pthread_mutexattr_t * attr)) {
+  return 0;
+}
+
+} // namespace __llvm_libc
diff --git a/libc/src/pthread/pthread_mutexattr_destroy.h b/libc/src/pthread/pthread_mutexattr_destroy.h
new file mode 100644
index 000000000000..2d7a5ed24e75
--- /dev/null
+++ b/libc/src/pthread/pthread_mutexattr_destroy.h
@@ -0,0 +1,20 @@
+//===-- Implementation header for pthread_mutexattr_destroy -----*- C++ -*-===//
+//
+// 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_SRC_PTHREAD_PTHREAD_MUTEXATTR_DESTROY_H
+#define LLVM_LIBC_SRC_PTHREAD_PTHREAD_MUTEXATTR_DESTROY_H
+
+#include <pthread.h>
+
+namespace __llvm_libc {
+
+int pthread_mutexattr_destroy(pthread_mutexattr_t *attr);
+
+} // namespace __llvm_libc
+
+#endif // LLVM_LIBC_SRC_PTHREAD_PTHREAD_MUTEXATTR_DESTROY_H
diff --git a/libc/src/pthread/pthread_mutexattr_getpshared.cpp b/libc/src/pthread/pthread_mutexattr_getpshared.cpp
new file mode 100644
index 000000000000..636bc1ae05ed
--- /dev/null
+++ b/libc/src/pthread/pthread_mutexattr_getpshared.cpp
@@ -0,0 +1,26 @@
+//===-- Implementation of the pthread_mutexattr_getpshared ----------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#include "pthread_mutexattr_getpshared.h"
+#include "pthread_mutexattr.h"
+
+#include "src/__support/common.h"
+
+#include <errno.h>
+
+namespace __llvm_libc {
+
+LLVM_LIBC_FUNCTION(int, pthread_mutexattr_getpshared,
+                   (const pthread_mutexattr_t *__restrict attr,
+                    int *__restrict pshared)) {
+  *pshared = (*attr & unsigned(PThreadMutexAttrPos::PSHARED_MASK)) >>
+             unsigned(PThreadMutexAttrPos::PSHARED_SHIFT);
+  return 0;
+}
+
+} // namespace __llvm_libc
diff --git a/libc/src/pthread/pthread_mutexattr_getpshared.h b/libc/src/pthread/pthread_mutexattr_getpshared.h
new file mode 100644
index 000000000000..12c60ea00b68
--- /dev/null
+++ b/libc/src/pthread/pthread_mutexattr_getpshared.h
@@ -0,0 +1,21 @@
+//===-- Implementation header for pthread_mutexattr_getpshared --*- C++ -*-===//
+//
+// 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_SRC_PTHREAD_PTHREAD_MUTEXATTR_GETPSHARED_H
+#define LLVM_LIBC_SRC_PTHREAD_PTHREAD_MUTEXATTR_GETPSHARED_H
+
+#include <pthread.h>
+
+namespace __llvm_libc {
+
+int pthread_mutexattr_getpshared(const pthread_mutexattr_t *__restrict attr,
+                                 int *__restrict pshared);
+
+} // namespace __llvm_libc
+
+#endif // LLVM_LIBC_SRC_PTHREAD_PTHREAD_MUTEXATTR_GETPSHARED_H
diff --git a/libc/src/pthread/pthread_mutexattr_getrobust.cpp b/libc/src/pthread/pthread_mutexattr_getrobust.cpp
new file mode 100644
index 000000000000..e3677ee415bf
--- /dev/null
+++ b/libc/src/pthread/pthread_mutexattr_getrobust.cpp
@@ -0,0 +1,26 @@
+//===-- Implementation of the pthread_mutexattr_getrobust -----------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#include "pthread_mutexattr_getrobust.h"
+#include "pthread_mutexattr.h"
+
+#include "src/__support/common.h"
+
+#include <errno.h>
+
+namespace __llvm_libc {
+
+LLVM_LIBC_FUNCTION(int, pthread_mutexattr_getrobust,
+                   (const pthread_mutexattr_t *__restrict attr,
+                    int *__restrict robust)) {
+  *robust = (*attr & unsigned(PThreadMutexAttrPos::ROBUST_MASK)) >>
+            unsigned(PThreadMutexAttrPos::ROBUST_SHIFT);
+  return 0;
+}
+
+} // namespace __llvm_libc
diff --git a/libc/src/pthread/pthread_mutexattr_getrobust.h b/libc/src/pthread/pthread_mutexattr_getrobust.h
new file mode 100644
index 000000000000..762cde0317fb
--- /dev/null
+++ b/libc/src/pthread/pthread_mutexattr_getrobust.h
@@ -0,0 +1,21 @@
+//===-- Implementation header for pthread_mutexattr_getrobust ---*- C++ -*-===//
+//
+// 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_SRC_PTHREAD_PTHREAD_MUTEXATTR_GETROBUST_H
+#define LLVM_LIBC_SRC_PTHREAD_PTHREAD_MUTEXATTR_GETROBUST_H
+
+#include <pthread.h>
+
+namespace __llvm_libc {
+
+int pthread_mutexattr_getrobust(const pthread_mutexattr_t *__restrict attr,
+                                int *__restrict robust);
+
+} // namespace __llvm_libc
+
+#endif // LLVM_LIBC_SRC_PTHREAD_PTHREAD_MUTEXATTR_GETROBUST_H
diff --git a/libc/src/pthread/pthread_mutexattr_gettype.cpp b/libc/src/pthread/pthread_mutexattr_gettype.cpp
new file mode 100644
index 000000000000..6a17e889fcf2
--- /dev/null
+++ b/libc/src/pthread/pthread_mutexattr_gettype.cpp
@@ -0,0 +1,26 @@
+//===-- Implementation of the pthread_mutexattr_gettype -------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#include "pthread_mutexattr_gettype.h"
+#include "pthread_mutexattr.h"
+
+#include "src/__support/common.h"
+
+#include <errno.h>
+
+namespace __llvm_libc {
+
+LLVM_LIBC_FUNCTION(int, pthread_mutexattr_gettype,
+                   (const pthread_mutexattr_t *__restrict attr,
+                    int *__restrict type)) {
+  *type = (*attr & unsigned(PThreadMutexAttrPos::TYPE_MASK)) >>
+          unsigned(PThreadMutexAttrPos::TYPE_SHIFT);
+  return 0;
+}
+
+} // namespace __llvm_libc
diff --git a/libc/src/pthread/pthread_mutexattr_gettype.h b/libc/src/pthread/pthread_mutexattr_gettype.h
new file mode 100644
index 000000000000..b0a7ea82e161
--- /dev/null
+++ b/libc/src/pthread/pthread_mutexattr_gettype.h
@@ -0,0 +1,21 @@
+//===-- Implementation header for pthread_mutexattr_gettype -----*- C++ -*-===//
+//
+// 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_SRC_PTHREAD_PTHREAD_MUTEXATTR_GETTYPE_H
+#define LLVM_LIBC_SRC_PTHREAD_PTHREAD_MUTEXATTR_GETTYPE_H
+
+#include <pthread.h>
+
+namespace __llvm_libc {
+
+int pthread_mutexattr_gettype(const pthread_mutexattr_t *__restrict attr,
+                              int *__restrict type);
+
+} // namespace __llvm_libc
+
+#endif // LLVM_LIBC_SRC_PTHREAD_PTHREAD_MUTEXATTR_GETTYPE_H
diff --git a/libc/src/pthread/pthread_mutexattr_init.cpp b/libc/src/pthread/pthread_mutexattr_init.cpp
new file mode 100644
index 000000000000..818aea1d388c
--- /dev/null
+++ b/libc/src/pthread/pthread_mutexattr_init.cpp
@@ -0,0 +1,23 @@
+//===-- Implementation of the pthread_mutexattr_init ----------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#include "pthread_mutexattr_init.h"
+#include "pthread_mutexattr.h"
+
+#include "src/__support/common.h"
+
+namespace __llvm_libc {
+
+LLVM_LIBC_FUNCTION(int, pthread_mutexattr_init, (pthread_mutexattr_t * attr)) {
+  // Set the default attributes and mark the attribute object as initiliazed
+  // by setting the first bit.
+  *attr = DEFAULT_MUTEXATTR;
+  return 0;
+}
+
+} // namespace __llvm_libc
diff --git a/libc/src/pthread/pthread_mutexattr_init.h b/libc/src/pthread/pthread_mutexattr_init.h
new file mode 100644
index 000000000000..af6cf29d9be6
--- /dev/null
+++ b/libc/src/pthread/pthread_mutexattr_init.h
@@ -0,0 +1,20 @@
+//===-- Implementation header for pthread_mutexattr_init --------*- C++ -*-===//
+//
+// 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_SRC_PTHREAD_PTHREAD_MUTEXATTR_INIT_H
+#define LLVM_LIBC_SRC_PTHREAD_PTHREAD_MUTEXATTR_INIT_H
+
+#include <pthread.h>
+
+namespace __llvm_libc {
+
+int pthread_mutexattr_init(pthread_mutexattr_t *attr);
+
+} // namespace __llvm_libc
+
+#endif // LLVM_LIBC_SRC_PTHREAD_PTHREAD_MUTEXATTR_INIT_H
diff --git a/libc/src/pthread/pthread_mutexattr_setpshared.cpp b/libc/src/pthread/pthread_mutexattr_setpshared.cpp
new file mode 100644
index 000000000000..1554031865a4
--- /dev/null
+++ b/libc/src/pthread/pthread_mutexattr_setpshared.cpp
@@ -0,0 +1,29 @@
+//===-- Implementation of the pthread_mutexattr_setpshared ----------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#include "pthread_mutexattr_setpshared.h"
+#include "pthread_mutexattr.h"
+
+#include "src/__support/common.h"
+
+#include <errno.h>
+#include <pthread.h>
+
+namespace __llvm_libc {
+
+LLVM_LIBC_FUNCTION(int, pthread_mutexattr_setpshared,
+                   (pthread_mutexattr_t *__restrict attr, int pshared)) {
+  if (pshared != PTHREAD_PROCESS_PRIVATE && pshared != PTHREAD_PROCESS_SHARED)
+    return EINVAL;
+  pthread_mutexattr_t old = *attr;
+  old &= ~unsigned(PThreadMutexAttrPos::PSHARED_MASK);
+  *attr = old | (pshared << unsigned(PThreadMutexAttrPos::PSHARED_SHIFT));
+  return 0;
+}
+
+} // namespace __llvm_libc
diff --git a/libc/src/pthread/pthread_mutexattr_setpshared.h b/libc/src/pthread/pthread_mutexattr_setpshared.h
new file mode 100644
index 000000000000..6b03ed4a8555
--- /dev/null
+++ b/libc/src/pthread/pthread_mutexattr_setpshared.h
@@ -0,0 +1,21 @@
+//===-- Implementation header for pthread_mutexattr_setpshared --*- C++ -*-===//
+//
+// 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_SRC_PTHREAD_PTHREAD_MUTEXATTR_SETpshared_H
+#define LLVM_LIBC_SRC_PTHREAD_PTHREAD_MUTEXATTR_SETpshared_H
+
+#include <pthread.h>
+
+namespace __llvm_libc {
+
+int pthread_mutexattr_setpshared(pthread_mutexattr_t *__restrict attr,
+                                 int pshared);
+
+} // namespace __llvm_libc
+
+#endif // LLVM_LIBC_SRC_PTHREAD_PTHREAD_MUTEXATTR_SETpshared_H
diff --git a/libc/src/pthread/pthread_mutexattr_setrobust.cpp b/libc/src/pthread/pthread_mutexattr_setrobust.cpp
new file mode 100644
index 000000000000..b09e3971d440
--- /dev/null
+++ b/libc/src/pthread/pthread_mutexattr_setrobust.cpp
@@ -0,0 +1,29 @@
+//===-- Implementation of the pthread_mutexattr_setrobust -----------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#include "pthread_mutexattr_setrobust.h"
+#include "pthread_mutexattr.h"
+
+#include "src/__support/common.h"
+
+#include <errno.h>
+#include <pthread.h>
+
+namespace __llvm_libc {
+
+LLVM_LIBC_FUNCTION(int, pthread_mutexattr_setrobust,
+                   (pthread_mutexattr_t *__restrict attr, int robust)) {
+  if (robust != PTHREAD_MUTEX_STALLED && robust != PTHREAD_MUTEX_ROBUST)
+    return EINVAL;
+  pthread_mutexattr_t old = *attr;
+  old &= ~unsigned(PThreadMutexAttrPos::ROBUST_MASK);
+  *attr = old | (robust << unsigned(PThreadMutexAttrPos::ROBUST_SHIFT));
+  return 0;
+}
+
+} // namespace __llvm_libc
diff --git a/libc/src/pthread/pthread_mutexattr_setrobust.h b/libc/src/pthread/pthread_mutexattr_setrobust.h
new file mode 100644
index 000000000000..253a319e6e50
--- /dev/null
+++ b/libc/src/pthread/pthread_mutexattr_setrobust.h
@@ -0,0 +1,21 @@
+//===-- Implementation header for pthread_mutexattr_setrobust ---*- C++ -*-===//
+//
+// 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_SRC_PTHREAD_PTHREAD_MUTEXATTR_SETROBUST_H
+#define LLVM_LIBC_SRC_PTHREAD_PTHREAD_MUTEXATTR_SETROBUST_H
+
+#include <pthread.h>
+
+namespace __llvm_libc {
+
+int pthread_mutexattr_setrobust(pthread_mutexattr_t *__restrict attr,
+                                int robust);
+
+} // namespace __llvm_libc
+
+#endif // LLVM_LIBC_SRC_PTHREAD_PTHREAD_MUTEXATTR_SETROBUST_H
diff --git a/libc/src/pthread/pthread_mutexattr_settype.cpp b/libc/src/pthread/pthread_mutexattr_settype.cpp
new file mode 100644
index 000000000000..e8134654e5e1
--- /dev/null
+++ b/libc/src/pthread/pthread_mutexattr_settype.cpp
@@ -0,0 +1,31 @@
+//===-- Implementation of the pthread_mutexattr_settype -------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#include "pthread_mutexattr_settype.h"
+#include "pthread_mutexattr.h"
+
+#include "src/__support/common.h"
+
+#include <errno.h>
+#include <pthread.h>
+
+namespace __llvm_libc {
+
+LLVM_LIBC_FUNCTION(int, pthread_mutexattr_settype,
+                   (pthread_mutexattr_t *__restrict attr, int type)) {
+  if (type != PTHREAD_MUTEX_NORMAL && type != PTHREAD_MUTEX_ERRORCHECK &&
+      type != PTHREAD_MUTEX_RECURSIVE) {
+    return EINVAL;
+  }
+  pthread_mutexattr_t old = *attr;
+  old &= ~unsigned(PThreadMutexAttrPos::TYPE_MASK);
+  *attr = old | (type << unsigned(PThreadMutexAttrPos::TYPE_SHIFT));
+  return 0;
+}
+
+} // namespace __llvm_libc
diff --git a/libc/src/pthread/pthread_mutexattr_settype.h b/libc/src/pthread/pthread_mutexattr_settype.h
new file mode 100644
index 000000000000..2411558ae217
--- /dev/null
+++ b/libc/src/pthread/pthread_mutexattr_settype.h
@@ -0,0 +1,20 @@
+//===-- Implementation header for pthread_mutexattr_settype -----*- C++ -*-===//
+//
+// 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_SRC_PTHREAD_PTHREAD_MUTEXATTR_SETTYPE_H
+#define LLVM_LIBC_SRC_PTHREAD_PTHREAD_MUTEXATTR_SETTYPE_H
+
+#include <pthread.h>
+
+namespace __llvm_libc {
+
+int pthread_mutexattr_settype(pthread_mutexattr_t *__restrict attr, int type);
+
+} // namespace __llvm_libc
+
+#endif // LLVM_LIBC_SRC_PTHREAD_PTHREAD_MUTEXATTR_SETTYPE_H
diff --git a/libc/test/src/CMakeLists.txt b/libc/test/src/CMakeLists.txt
index db0742f417d8..cbab9d121e2c 100644
--- a/libc/test/src/CMakeLists.txt
+++ b/libc/test/src/CMakeLists.txt
@@ -52,6 +52,10 @@ add_subdirectory(stdio)
 add_subdirectory(threads)
 add_subdirectory(time)
 
+if(${LIBC_TARGET_OS} STREQUAL "linux")
+  add_subdirectory(pthread)
+endif()
+
 set(public_test ${CMAKE_CURRENT_BINARY_DIR}/public_api_test.cpp)
 
 set(entrypoints_name_list "")
diff --git a/libc/test/src/pthread/CMakeLists.txt b/libc/test/src/pthread/CMakeLists.txt
new file mode 100644
index 000000000000..552c7feca2d6
--- /dev/null
+++ b/libc/test/src/pthread/CMakeLists.txt
@@ -0,0 +1,20 @@
+add_libc_testsuite(libc_pthread_unittests)
+
+add_libc_unittest(
+  pthread_mutexattr_test
+  SUITE
+    libc_pthread_unittests
+  SRCS
+    pthread_mutexattr_test.cpp
+  DEPENDS
+    libc.include.errno
+    libc.include.pthread
+    libc.src.pthread.pthread_mutexattr_destroy
+    libc.src.pthread.pthread_mutexattr_init
+    libc.src.pthread.pthread_mutexattr_getpshared
+    libc.src.pthread.pthread_mutexattr_getrobust
+    libc.src.pthread.pthread_mutexattr_gettype
+    libc.src.pthread.pthread_mutexattr_setpshared
+    libc.src.pthread.pthread_mutexattr_setrobust
+    libc.src.pthread.pthread_mutexattr_settype
+)
diff --git a/libc/test/src/pthread/pthread_mutexattr_test.cpp b/libc/test/src/pthread/pthread_mutexattr_test.cpp
new file mode 100644
index 000000000000..19c9365dd16d
--- /dev/null
+++ b/libc/test/src/pthread/pthread_mutexattr_test.cpp
@@ -0,0 +1,91 @@
+//===-- Unittests for pthread_mutexattr_t ---------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#include "src/pthread/pthread_mutexattr_destroy.h"
+#include "src/pthread/pthread_mutexattr_getpshared.h"
+#include "src/pthread/pthread_mutexattr_getrobust.h"
+#include "src/pthread/pthread_mutexattr_gettype.h"
+#include "src/pthread/pthread_mutexattr_init.h"
+#include "src/pthread/pthread_mutexattr_setpshared.h"
+#include "src/pthread/pthread_mutexattr_setrobust.h"
+#include "src/pthread/pthread_mutexattr_settype.h"
+#include "utils/UnitTest/Test.h"
+
+#include <errno.h>
+#include <pthread.h>
+
+TEST(LlvmLibcPThreadMutexAttrTest, InitAndDestroy) {
+  pthread_mutexattr_t attr;
+  ASSERT_EQ(__llvm_libc::pthread_mutexattr_init(&attr), 0);
+  ASSERT_EQ(__llvm_libc::pthread_mutexattr_destroy(&attr), 0);
+}
+
+TEST(LlvmLibcPThreadMutexAttrTest, SetAndGetType) {
+  int type;
+  pthread_mutexattr_t attr;
+  ASSERT_EQ(__llvm_libc::pthread_mutexattr_init(&attr), 0);
+  ASSERT_EQ(__llvm_libc::pthread_mutexattr_gettype(&attr, &type), 0);
+  ASSERT_EQ(type, int(PTHREAD_MUTEX_DEFAULT));
+
+  ASSERT_EQ(
+      __llvm_libc::pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_RECURSIVE),
+      0);
+  ASSERT_EQ(__llvm_libc::pthread_mutexattr_gettype(&attr, &type), 0);
+  ASSERT_EQ(type, int(PTHREAD_MUTEX_RECURSIVE));
+
+  ASSERT_EQ(
+      __llvm_libc::pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_ERRORCHECK),
+      0);
+  ASSERT_EQ(__llvm_libc::pthread_mutexattr_gettype(&attr, &type), 0);
+  ASSERT_EQ(type, int(PTHREAD_MUTEX_ERRORCHECK));
+
+  ASSERT_EQ(__llvm_libc::pthread_mutexattr_settype(&attr, 0xBAD), EINVAL);
+}
+
+TEST(LlvmLibcPThreadMutexAttrTest, SetAndGetRobust) {
+  int robust;
+  pthread_mutexattr_t attr;
+  ASSERT_EQ(__llvm_libc::pthread_mutexattr_init(&attr), 0);
+  ASSERT_EQ(__llvm_libc::pthread_mutexattr_getrobust(&attr, &robust), 0);
+  ASSERT_EQ(robust, int(PTHREAD_MUTEX_STALLED));
+
+  ASSERT_EQ(
+      __llvm_libc::pthread_mutexattr_setrobust(&attr, PTHREAD_MUTEX_ROBUST), 0);
+  ASSERT_EQ(__llvm_libc::pthread_mutexattr_getrobust(&attr, &robust), 0);
+  ASSERT_EQ(robust, int(PTHREAD_MUTEX_ROBUST));
+
+  ASSERT_EQ(
+      __llvm_libc::pthread_mutexattr_setrobust(&attr, PTHREAD_MUTEX_STALLED),
+      0);
+  ASSERT_EQ(__llvm_libc::pthread_mutexattr_getrobust(&attr, &robust), 0);
+  ASSERT_EQ(robust, int(PTHREAD_MUTEX_STALLED));
+
+  ASSERT_EQ(__llvm_libc::pthread_mutexattr_setrobust(&attr, 0xBAD), EINVAL);
+}
+
+TEST(LlvmLibcPThreadMutexAttrTest, SetAndGetPShared) {
+  int pshared;
+  pthread_mutexattr_t attr;
+  ASSERT_EQ(__llvm_libc::pthread_mutexattr_init(&attr), 0);
+  ASSERT_EQ(__llvm_libc::pthread_mutexattr_getpshared(&attr, &pshared), 0);
+  ASSERT_EQ(pshared, int(PTHREAD_PROCESS_PRIVATE));
+
+  ASSERT_EQ(
+      __llvm_libc::pthread_mutexattr_setpshared(&attr, PTHREAD_PROCESS_SHARED),
+      0);
+  ASSERT_EQ(__llvm_libc::pthread_mutexattr_getpshared(&attr, &pshared), 0);
+  ASSERT_EQ(pshared, int(PTHREAD_PROCESS_SHARED));
+
+  ASSERT_EQ(
+      __llvm_libc::pthread_mutexattr_setpshared(&attr, PTHREAD_PROCESS_PRIVATE),
+      0);
+  ASSERT_EQ(__llvm_libc::pthread_mutexattr_getpshared(&attr, &pshared), 0);
+  ASSERT_EQ(pshared, int(PTHREAD_PROCESS_PRIVATE));
+
+  ASSERT_EQ(__llvm_libc::pthread_mutexattr_setpshared(&attr, 0xBAD), EINVAL);
+}