From 2e744276988acd52b967d2505c42ef170147b5f9 Mon Sep 17 00:00:00 2001 From: Tom Tromey Date: Tue, 10 Dec 2019 14:16:19 -0700 Subject: [PATCH] Fix build on macOS PR build/25268 points out that the build fails on macOS, because on macOS the "pthread_setname_np" function takes a single argument. This patch fixes the problem, by introducing a new adapter function that handles both styles of pthread_setname_np. This change also meant moving the pthread_setname_np call to the thread function, because macOS only permits setting the name of the current thread. This means that there can be a brief window when gdb will see the wrong name; but I think this is a minor concern. Tested by rebuilding on x86-64 Fedora 30, and on macOS High Sierra. On Linux I also debugged gdb to ensure that the thread names are still set correctly. gdb/ChangeLog 2019-12-11 Tom Tromey PR build/25268: * gdbsupport/thread-pool.c (set_thread_name): New function. (thread_pool::set_thread_count): Don't call pthread_setname_np. (thread_pool::thread_function): Call set_thread_name. Change-Id: Id7bf28d99ca27a893a9fc87ebb90b15a9c2a9cb4 --- gdb/ChangeLog | 7 +++++++ gdb/gdbsupport/thread-pool.c | 35 +++++++++++++++++++++++++++++++---- 2 files changed, 38 insertions(+), 4 deletions(-) diff --git a/gdb/ChangeLog b/gdb/ChangeLog index 8355da596f7..7fe3a2938c1 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,10 @@ +2019-12-11 Tom Tromey + + PR build/25268: + * gdbsupport/thread-pool.c (set_thread_name): New function. + (thread_pool::set_thread_count): Don't call pthread_setname_np. + (thread_pool::thread_function): Call set_thread_name. + 2019-12-11 Tom Tromey * fbsd-tdep.c (fbsd_core_info_proc_status): Cast result of diff --git a/gdb/gdbsupport/thread-pool.c b/gdb/gdbsupport/thread-pool.c index d19ae02e3ef..f6ea6d8b171 100644 --- a/gdb/gdbsupport/thread-pool.c +++ b/gdb/gdbsupport/thread-pool.c @@ -25,6 +25,7 @@ #include "gdbsupport/alt-stack.h" #include "gdbsupport/block-signals.h" #include +#include "diagnostics.h" /* On the off chance that we have the pthread library on a Windows host, but std::thread is not using it, avoid calling @@ -36,8 +37,31 @@ #endif #ifdef USE_PTHREAD_SETNAME_NP + #include -#endif + +DIAGNOSTIC_PUSH +DIAGNOSTIC_IGNORE_UNUSED_FUNCTION + +/* Handle platform discrepancies in pthread_setname_np: macOS uses a + single-argument form, while Linux uses a two-argument form. This + wrapper handles the difference. */ + +static void +set_thread_name (int (*set_name) (pthread_t, const char *), const char *name) +{ + set_name (pthread_self (), name); +} + +static void +set_thread_name (void (*set_name) (const char *), const char *name) +{ + set_name (name); +} + +DIAGNOSTIC_POP + +#endif /* USE_PTHREAD_SETNAME_NP */ namespace gdb { @@ -75,9 +99,6 @@ thread_pool::set_thread_count (size_t num_threads) for (size_t i = m_thread_count; i < num_threads; ++i) { std::thread thread (&thread_pool::thread_function, this); -#ifdef USE_PTHREAD_SETNAME_NP - pthread_setname_np (thread.native_handle (), "gdb worker"); -#endif thread.detach (); } } @@ -115,6 +136,12 @@ thread_pool::post_task (std::function func) void thread_pool::thread_function () { +#ifdef USE_PTHREAD_SETNAME_NP + /* This must be done here, because on macOS one can only set the + name of the current thread. */ + set_thread_name (pthread_setname_np, "gdb worker"); +#endif + /* Ensure that SIGSEGV is delivered to an alternate signal stack. */ gdb::alternate_signal_stack signal_stack; -- 2.30.2