From 6dae830ea0bff809a747cd3767371f219981b781 Mon Sep 17 00:00:00 2001
From: Nathaniel Wesley Filardo <nwf20@cl.cam.ac.uk>
Date: Sat, 16 May 2020 12:45:51 +0100
Subject: [PATCH] Use cmake to find backtrace() (#187)

On FreeBSD, this notably requires the use of -lexecinfo, as backtrace()
is not available in -lc.  Rather than testing in C, test in cmake.
---
 CMakeLists.txt      | 8 ++++++++
 src/pal/pal_posix.h | 7 +++----
 2 files changed, 11 insertions(+), 4 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index a2896dd..221086d 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -176,6 +176,14 @@ if(NOT DEFINED SNMALLOC_ONLY_HEADER_LIBRARY)
         add_compile_options(-march=native)
       endif()
     endif()
+
+    find_package(Backtrace)
+    if(${Backtrace_FOUND})
+      target_compile_definitions(snmalloc_lib INTERFACE -DBACKTRACE_HEADER="${Backtrace_HEADER}")
+      target_link_libraries(snmalloc_lib INTERFACE ${Backtrace_LIBRARIES})
+      target_include_directories(snmalloc_lib INTERFACE ${Backtrace_INCLUD_DIRS})
+    endif()
+
   endif()
 
   macro(subdirlist result curdir)
diff --git a/src/pal/pal_posix.h b/src/pal/pal_posix.h
index 0f7eb85..260bd3d 100644
--- a/src/pal/pal_posix.h
+++ b/src/pal/pal_posix.h
@@ -2,9 +2,8 @@
 
 #include "../ds/address.h"
 #include "../mem/allocconfig.h"
-#if __has_include(<execinfo.h>)
-#  define SNMALLOC_HAS_BACKTRACE 1
-#  include <execinfo.h>
+#if defined(BACKTRACE_HEADER)
+#  include BACKTRACE_HEADER
 #endif
 #include <stdio.h>
 #include <stdlib.h>
@@ -42,7 +41,7 @@ namespace snmalloc
 
     static void print_stack_trace()
     {
-#ifdef SNMALLOC_HAS_BACKTRACE
+#ifdef BACKTRACE_HEADER
       constexpr int SIZE = 1024;
       void* buffer[SIZE];
       auto nptrs = backtrace(buffer, SIZE);