From be7725f0fde6c1fb1c00dd7ff54ef874e069ebcd Mon Sep 17 00:00:00 2001
From: Alastair Houghton <ahoughton@apple.com>
Date: Fri, 9 Jun 2023 09:04:27 +0100
Subject: [PATCH] [Backtracing][Linux] Include declarations for gettid() and
 tgkill().

Older glibc doesn't include these.  Nor does Musl, it seems.  The
previous fix put the gettid() declaration too far down the file.

rdar://110417355
---
 stdlib/public/runtime/CrashHandlerLinux.cpp | 18 ++++++++++++------
 1 file changed, 12 insertions(+), 6 deletions(-)

diff --git a/stdlib/public/runtime/CrashHandlerLinux.cpp b/stdlib/public/runtime/CrashHandlerLinux.cpp
index 42f83ca616847..2913245b97566 100644
--- a/stdlib/public/runtime/CrashHandlerLinux.cpp
+++ b/stdlib/public/runtime/CrashHandlerLinux.cpp
@@ -183,6 +183,18 @@ _swift_installCrashHandler()
 
 namespace {
 
+// Older glibc and musl don't have these two syscalls
+pid_t
+gettid()
+{
+  return (pid_t)syscall(SYS_gettid);
+}
+
+int
+tgkill(int tgid, int tid, int sig) {
+  return syscall(SYS_tgkill, tgid, tid, sig);
+}
+
 void
 reset_signal(int signum)
 {
@@ -296,12 +308,6 @@ getdents(int fd, void *buf, size_t bufsiz)
   return syscall(SYS_getdents64, fd, buf, bufsiz);
 }
 
-pid_t
-gettid()
-{
-  return (pid_t)syscall(SYS_gettid);
-}
-
 /* Stop all other threads in this process; we do this by establishing a
    signal handler for SIGPROF, then iterating through the threads sending
    SIGPROF.