From 698e107ee970ae719b6cad10a783b1957dc11281 Mon Sep 17 00:00:00 2001
From: Yichao Yu <yyc1992@gmail.com>
Date: Fri, 15 Apr 2016 20:53:03 -0400
Subject: [PATCH] Workaround clang bug on OSX when the tls variable is too
 large

By allocating the buffer at runtime with `mmap`.

Fixes #15647
---
 src/julia_threads.h | 3 ++-
 src/threading.c     | 7 +++++++
 2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/src/julia_threads.h b/src/julia_threads.h
index f9546bf091e7f..0444549160488 100644
--- a/src/julia_threads.h
+++ b/src/julia_threads.h
@@ -52,7 +52,8 @@ typedef struct _jl_tls_states_t {
     jl_jmp_buf *safe_restore;
     int16_t tid;
     size_t bt_size;
-    uintptr_t bt_data[JL_MAX_BT_SIZE + 1];
+    // JL_MAX_BT_SIZE + 1 elements long
+    uintptr_t *bt_data;
 } jl_tls_states_t;
 
 #ifdef __MIC__
diff --git a/src/threading.c b/src/threading.c
index 6479813ec4486..89b01db3f9f1f 100644
--- a/src/threading.c
+++ b/src/threading.c
@@ -105,6 +105,13 @@ static void ti_initthread(int16_t tid)
     ptls->pgcstack = NULL;
     ptls->gc_state = 0; // GC unsafe
     ptls->current_module = NULL;
+    void *bt_data = malloc(sizeof(uintptr_t) * (JL_MAX_BT_SIZE + 1));
+    if (bt_data == NULL) {
+        jl_printf(JL_STDERR, "could not allocate backtrace buffer\n");
+        gc_debug_critical_error();
+        abort();
+    }
+    ptls->bt_data = (uintptr_t*)bt_data;
 #ifdef JULIA_ENABLE_THREADING
     jl_all_heaps[tid] = jl_mk_thread_heap();
 #else