Make ThreadLocalBuffer a class rather than a macro.

Bug: 19995392
Change-Id: I497c512648fbe66257da3fb3bcd5c9911f983705

10 files changed, 88 insertions, 92 deletions

diff --git a/libc/bionic/libgen.cpp b/libc/bionic/libgen.cpp
index b98f504b0..2f29d7b63 100644
--- a/libc/bionic/libgen.cpp
+++ b/libc/bionic/libgen.cpp
@@ -36,6 +36,9 @@
 
 #include "private/ThreadLocalBuffer.h"
 
+static ThreadLocalBuffer<char, MAXPATHLEN> g_basename_tls_buffer;
+static ThreadLocalBuffer<char, MAXPATHLEN> g_dirname_tls_buffer;
+
 __LIBC64_HIDDEN__ int basename_r(const char* path, char* buffer, size_t buffer_size) {
   const char* startp = NULL;
   const char* endp = NULL;
@@ -147,17 +150,14 @@ __LIBC64_HIDDEN__ int dirname_r(const char* path, char* buffer, size_t buffer_si
   return result;
 }
 
-GLOBAL_INIT_THREAD_LOCAL_BUFFER(basename);
-GLOBAL_INIT_THREAD_LOCAL_BUFFER(dirname);
-
 char* basename(const char* path) {
-  LOCAL_INIT_THREAD_LOCAL_BUFFER(char*, basename, MAXPATHLEN);
-  int rc = basename_r(path, basename_tls_buffer, basename_tls_buffer_size);
-  return (rc < 0) ? NULL : basename_tls_buffer;
+  char* buf = g_basename_tls_buffer.get();
+  int rc = basename_r(path, buf, g_basename_tls_buffer.size());
+  return (rc < 0) ? NULL : buf;
 }
 
 char* dirname(const char* path) {
-  LOCAL_INIT_THREAD_LOCAL_BUFFER(char*, dirname, MAXPATHLEN);
-  int rc = dirname_r(path, dirname_tls_buffer, dirname_tls_buffer_size);
-  return (rc < 0) ? NULL : dirname_tls_buffer;
+  char* buf = g_dirname_tls_buffer.get();
+  int rc = dirname_r(path, buf, g_dirname_tls_buffer.size());
+  return (rc < 0) ? NULL : buf;
 }
diff --git a/libc/bionic/mntent.cpp b/libc/bionic/mntent.cpp
index 4afacda60..d169e2930 100644
--- a/libc/bionic/mntent.cpp
+++ b/libc/bionic/mntent.cpp
@@ -31,14 +31,13 @@
 
 #include "private/ThreadLocalBuffer.h"
 
-GLOBAL_INIT_THREAD_LOCAL_BUFFER(getmntent_mntent);
-GLOBAL_INIT_THREAD_LOCAL_BUFFER(getmntent_strings);
+static ThreadLocalBuffer<mntent> g_getmntent_mntent_tls_buffer;
+static ThreadLocalBuffer<char, BUFSIZ> g_getmntent_strings_tls_buffer;
 
 mntent* getmntent(FILE* fp) {
-  LOCAL_INIT_THREAD_LOCAL_BUFFER(mntent*, getmntent_mntent, sizeof(mntent));
-  LOCAL_INIT_THREAD_LOCAL_BUFFER(char*, getmntent_strings, BUFSIZ);
-  return getmntent_r(fp, getmntent_mntent_tls_buffer,
-                     getmntent_strings_tls_buffer, getmntent_strings_tls_buffer_size);
+  return getmntent_r(fp, g_getmntent_mntent_tls_buffer.get(),
+                     g_getmntent_strings_tls_buffer.get(),
+                     g_getmntent_strings_tls_buffer.size());
 }
 
 mntent* getmntent_r(FILE* fp, struct mntent* e, char* buf, int buf_len) {
diff --git a/libc/bionic/pty.cpp b/libc/bionic/pty.cpp
index 884714799..1a3784753 100644
--- a/libc/bionic/pty.cpp
+++ b/libc/bionic/pty.cpp
@@ -38,8 +38,8 @@
 
 #include "private/ThreadLocalBuffer.h"
 
-GLOBAL_INIT_THREAD_LOCAL_BUFFER(ptsname);
-GLOBAL_INIT_THREAD_LOCAL_BUFFER(ttyname);
+static ThreadLocalBuffer<char, 32> g_ptsname_tls_buffer;
+static ThreadLocalBuffer<char, 64> g_ttyname_tls_buffer;
 
 int getpt() {
   return posix_openpt(O_RDWR|O_NOCTTY);
@@ -54,9 +54,9 @@ int posix_openpt(int flags) {
 }
 
 char* ptsname(int fd) {
-  LOCAL_INIT_THREAD_LOCAL_BUFFER(char*, ptsname, 32);
-  int error = ptsname_r(fd, ptsname_tls_buffer, ptsname_tls_buffer_size);
-  return (error == 0) ? ptsname_tls_buffer : NULL;
+  char* buf = g_ptsname_tls_buffer.get();
+  int error = ptsname_r(fd, buf, g_ptsname_tls_buffer.size());
+  return (error == 0) ? buf : NULL;
 }
 
 int ptsname_r(int fd, char* buf, size_t len) {
@@ -80,9 +80,9 @@ int ptsname_r(int fd, char* buf, size_t len) {
 }
 
 char* ttyname(int fd) {
-  LOCAL_INIT_THREAD_LOCAL_BUFFER(char*, ttyname, 64);
-  int error = ttyname_r(fd, ttyname_tls_buffer, ttyname_tls_buffer_size);
-  return (error == 0) ? ttyname_tls_buffer : NULL;
+  char* buf = g_ttyname_tls_buffer.get();
+  int error = ttyname_r(fd, buf, g_ttyname_tls_buffer.size());
+  return (error == 0) ? buf : NULL;
 }
 
 int ttyname_r(int fd, char* buf, size_t len) {
diff --git a/libc/bionic/strerror.cpp b/libc/bionic/strerror.cpp
index d1518ffc4..f74194fd9 100644
--- a/libc/bionic/strerror.cpp
+++ b/libc/bionic/strerror.cpp
@@ -31,16 +31,16 @@
 
 extern "C" const char* __strerror_lookup(int);
 
-GLOBAL_INIT_THREAD_LOCAL_BUFFER(strerror);
+static ThreadLocalBuffer<char, NL_TEXTMAX> g_strerror_tls_buffer;
 
 char* strerror(int error_number) {
   // Just return the original constant in the easy cases.
   char* result = const_cast<char*>(__strerror_lookup(error_number));
-  if (result != NULL) {
+  if (result != nullptr) {
     return result;
   }
 
-  LOCAL_INIT_THREAD_LOCAL_BUFFER(char*, strerror, NL_TEXTMAX);
-  strerror_r(error_number, strerror_tls_buffer, strerror_tls_buffer_size);
-  return strerror_tls_buffer;
+  result = g_strerror_tls_buffer.get();
+  strerror_r(error_number, result, g_strerror_tls_buffer.size());
+  return result;
 }
diff --git a/libc/bionic/strsignal.cpp b/libc/bionic/strsignal.cpp
index 9f0193acf..c389ddd3b 100644
--- a/libc/bionic/strsignal.cpp
+++ b/libc/bionic/strsignal.cpp
@@ -32,7 +32,7 @@
 extern "C" const char* __strsignal_lookup(int);
 extern "C" const char* __strsignal(int, char*, size_t);
 
-GLOBAL_INIT_THREAD_LOCAL_BUFFER(strsignal);
+static ThreadLocalBuffer<char, NL_TEXTMAX> g_strsignal_tls_buffer;
 
 char* strsignal(int signal_number) {
   // Just return the original constant in the easy cases.
@@ -41,6 +41,6 @@ char* strsignal(int signal_number) {
     return result;
   }
 
-  LOCAL_INIT_THREAD_LOCAL_BUFFER(char*, strsignal, NL_TEXTMAX);
-  return const_cast<char*>(__strsignal(signal_number, strsignal_tls_buffer, strsignal_tls_buffer_size));
+  return const_cast<char*>(__strsignal(signal_number, g_strsignal_tls_buffer.get(),
+                                       g_strsignal_tls_buffer.size()));
 }
diff --git a/libc/bionic/stubs.cpp b/libc/bionic/stubs.cpp
index f9a31b9af..d4440c434 100644
--- a/libc/bionic/stubs.cpp
+++ b/libc/bionic/stubs.cpp
@@ -49,25 +49,12 @@
 // functions to share state, but <grp.h> functions can't clobber <passwd.h>
 // functions' state and vice versa.
 
-GLOBAL_INIT_THREAD_LOCAL_BUFFER(group);
-
 struct group_state_t {
   group group_;
   char* group_members_[2];
   char group_name_buffer_[32];
 };
 
-static group_state_t* __group_state() {
-  LOCAL_INIT_THREAD_LOCAL_BUFFER(group_state_t*, group, sizeof(group_state_t));
-  if (group_tls_buffer != NULL) {
-    memset(group_tls_buffer, 0, sizeof(group_state_t));
-    group_tls_buffer->group_.gr_mem = group_tls_buffer->group_members_;
-  }
-  return group_tls_buffer;
-}
-
-GLOBAL_INIT_THREAD_LOCAL_BUFFER(passwd);
-
 struct passwd_state_t {
   passwd passwd_;
   char name_buffer_[32];
@@ -75,9 +62,16 @@ struct passwd_state_t {
   char sh_buffer_[32];
 };
 
-static passwd_state_t* __passwd_state() {
-  LOCAL_INIT_THREAD_LOCAL_BUFFER(passwd_state_t*, passwd, sizeof(passwd_state_t));
-  return passwd_tls_buffer;
+static ThreadLocalBuffer<group_state_t> g_group_tls_buffer;
+static ThreadLocalBuffer<passwd_state_t> g_passwd_tls_buffer;
+
+static group_state_t* __group_state() {
+  group_state_t* result = g_group_tls_buffer.get();
+  if (result != nullptr) {
+    memset(result, 0, sizeof(group_state_t));
+    result->group_.gr_mem = result->group_members_;
+  }
+  return result;
 }
 
 static int do_getpw_r(int by_name, const char* name, uid_t uid,
@@ -361,7 +355,7 @@ static group* app_id_to_group(gid_t gid, group_state_t* state) {
 }
 
 passwd* getpwuid(uid_t uid) { // NOLINT: implementing bad function.
-  passwd_state_t* state = __passwd_state();
+  passwd_state_t* state = g_passwd_tls_buffer.get();
   if (state == NULL) {
     return NULL;
   }
@@ -374,7 +368,7 @@ passwd* getpwuid(uid_t uid) { // NOLINT: implementing bad function.
 }
 
 passwd* getpwnam(const char* login) { // NOLINT: implementing bad function.
-  passwd_state_t* state = __passwd_state();
+  passwd_state_t* state = g_passwd_tls_buffer.get();
   if (state == NULL) {
     return NULL;
   }
diff --git a/libc/dns/resolv/res_state.c b/libc/dns/resolv/res_state.c
index 459f07394..afccd9979 100644
--- a/libc/dns/resolv/res_state.c
+++ b/libc/dns/resolv/res_state.c
@@ -39,8 +39,6 @@
 #define _REALLY_INCLUDE_SYS__SYSTEM_PROPERTIES_H_
 #include <sys/_system_properties.h>
 
-#include "private/ThreadLocalBuffer.h"
-
 /* Set to 1 to enable debug traces */
 #define DEBUG 0
 
@@ -105,7 +103,11 @@ _res_thread_free( void*  _rt )
     free(rt);
 }
 
-BIONIC_PTHREAD_KEY_WITH_CONSTRUCTOR(_res_key, _res_thread_free);
+static pthread_key_t _res_key;
+
+__attribute__((constructor)) static void __res_key_init() {
+    pthread_key_create(&_res_key, _res_thread_free);
+}
 
 static _res_thread*
 _res_thread_get(void)
diff --git a/libc/private/ThreadLocalBuffer.h b/libc/private/ThreadLocalBuffer.h
index cc4731703..5e436659a 100644
--- a/libc/private/ThreadLocalBuffer.h
+++ b/libc/private/ThreadLocalBuffer.h
@@ -32,32 +32,30 @@
 #include <malloc.h>
 #include <pthread.h>
 
-// libstdc++ currently contains __cxa_guard_acquire and __cxa_guard_release,
-// so we make do with macros instead of a C++ class.
-// TODO: move __cxa_guard_acquire and __cxa_guard_release into libc.
-
-// We used to use pthread_once to initialize the keys, but life is more predictable
-// if we allocate them all up front when the C library starts up, via __constructor__.
-#define BIONIC_PTHREAD_KEY_WITH_CONSTRUCTOR(key_name, key_destructor) \
-  static pthread_key_t key_name; \
-  __attribute__((constructor)) static void __bionic_tls_ ## key_name ## _key_init() { \
-    pthread_key_create(&key_name, key_destructor); \
+// TODO: use __thread instead?
+
+template <typename T, size_t Size = sizeof(T)>
+class ThreadLocalBuffer {
+ public:
+  ThreadLocalBuffer() {
+    // We used to use pthread_once to initialize the keys, but life is more predictable
+    // if we allocate them all up front when the C library starts up, via __constructor__.
+    pthread_key_create(&key_, free);
+  }
+
+  T* get() {
+    T* result = reinterpret_cast<T*>(pthread_getspecific(key_));
+    if (result == nullptr) {
+      result = reinterpret_cast<T*>(calloc(1, Size));
+      pthread_setspecific(key_, result);
+    }
+    return result;
   }
 
-#define GLOBAL_INIT_THREAD_LOCAL_BUFFER(name) \
-  static void __bionic_tls_ ## name ## _key_destroy(void* buffer) { \
-    free(buffer); \
-  } \
-  BIONIC_PTHREAD_KEY_WITH_CONSTRUCTOR(__bionic_tls_ ## name ## _key, __bionic_tls_ ## name ## _key_destroy)
-
-// Leaves "name_tls_buffer" and "name_tls_buffer_size" defined and initialized.
-#define LOCAL_INIT_THREAD_LOCAL_BUFFER(type, name, byte_count) \
-  type name ## _tls_buffer = \
-      reinterpret_cast<type>(pthread_getspecific(__bionic_tls_ ## name ## _key)); \
-  if (name ## _tls_buffer == NULL) { \
-    name ## _tls_buffer = reinterpret_cast<type>(calloc(1, byte_count)); \
-    pthread_setspecific(__bionic_tls_ ## name ## _key, name ## _tls_buffer); \
-  } \
-  const size_t name ## _tls_buffer_size __attribute__((unused)) = byte_count
+  size_t size() { return Size; }
+
+ private:
+  pthread_key_t key_;
+};
 
 #endif // _BIONIC_THREAD_LOCAL_BUFFER_H_included
diff --git a/libc/private/bionic_tls.h b/libc/private/bionic_tls.h
index 1ab8d4a26..414d1711d 100644
--- a/libc/private/bionic_tls.h
+++ b/libc/private/bionic_tls.h
@@ -72,22 +72,26 @@ enum {
 
 /*
  * Bionic uses some pthread keys internally. All pthread keys used internally
- * should be created in constructors, except for keys that may be used in or before constructors.
+ * should be created in constructors, except for keys that may be used in or
+ * before constructors.
+ *
  * We need to manually maintain the count of pthread keys used internally, but
  * pthread_test should fail if we forget.
- * Following are current pthread keys used internally by libc:
- *  basename               libc (GLOBAL_INIT_THREAD_LOCAL_BUFFER)
- *  dirname                libc (GLOBAL_INIT_THREAD_LOCAL_BUFFER)
+ *
+ * These are the pthread keys currently used internally by libc:
+ *
+ *  basename               libc (ThreadLocalBuffer)
+ *  dirname                libc (ThreadLocalBuffer)
  *  uselocale              libc (can be used in constructors)
- *  getmntent_mntent       libc (GLOBAL_INIT_THREAD_LOCAL_BUFFER)
- *  getmntent_strings      libc (GLOBAL_INIT_THREAD_LOCAL_BUFFER)
- *  ptsname                libc (GLOBAL_INIT_THREAD_LOCAL_BUFFER)
- *  ttyname                libc (GLOBAL_INIT_THREAD_LOCAL_BUFFER)
- *  strerror               libc (GLOBAL_INIT_THREAD_LOCAL_BUFFER)
- *  strsignal              libc (GLOBAL_INIT_THREAD_LOCAL_BUFFER)
- *  passwd                 libc (GLOBAL_INIT_THREAD_LOCAL_BUFFER)
- *  group                  libc (GLOBAL_INIT_THREAD_LOCAL_BUFFER)
- *  _res_key               libc (BIONIC_PTHREAD_KEY_WITH_CONSTRUCTOR)
+ *  getmntent_mntent       libc (ThreadLocalBuffer)
+ *  getmntent_strings      libc (ThreadLocalBuffer)
+ *  ptsname                libc (ThreadLocalBuffer)
+ *  ttyname                libc (ThreadLocalBuffer)
+ *  strerror               libc (ThreadLocalBuffer)
+ *  strsignal              libc (ThreadLocalBuffer)
+ *  passwd                 libc (ThreadLocalBuffer)
+ *  group                  libc (ThreadLocalBuffer)
+ *  _res_key               libc (constructor in BSD code)
  */
 
 #define LIBC_PTHREAD_KEY_RESERVED_COUNT 12
diff --git a/tests/pthread_test.cpp b/tests/pthread_test.cpp
index 13d743f87..16bf9c0cb 100644
--- a/tests/pthread_test.cpp
+++ b/tests/pthread_test.cpp
@@ -68,8 +68,7 @@ TEST(pthread, pthread_key_many_distinct) {
 
   for (int i = 0; i < nkeys; ++i) {
     pthread_key_t key;
-    // If this fails, it's likely that GLOBAL_INIT_THREAD_LOCAL_BUFFER_COUNT is
-    // wrong.
+    // If this fails, it's likely that LIBC_PTHREAD_KEY_RESERVED_COUNT is wrong.
     ASSERT_EQ(0, pthread_key_create(&key, NULL)) << i << " of " << nkeys;
     keys.push_back(key);
     ASSERT_EQ(0, pthread_setspecific(key, reinterpret_cast<void*>(i)));