From c9ac607bd3bf2cc1cfb941e54e6bcd53f2fcc59d Mon Sep 17 00:00:00 2001
From: Andrew Kelley <superjoe30@gmail.com>
Date: Mon, 15 Jan 2018 00:14:14 -0500
Subject: [PATCH] add builtin.have_error_return_tracing

---
 src/codegen.cpp       |  1 +
 std/special/panic.zig | 10 ++++++----
 2 files changed, 7 insertions(+), 4 deletions(-)

diff --git a/src/codegen.cpp b/src/codegen.cpp
index 5113aa7275..c72bb07c8b 100644
--- a/src/codegen.cpp
+++ b/src/codegen.cpp
@@ -5444,6 +5444,7 @@ static void define_builtin_compile_vars(CodeGen *g) {
     buf_appendf(contents, "pub const object_format = ObjectFormat.%s;\n", cur_obj_fmt);
     buf_appendf(contents, "pub const mode = %s;\n", build_mode_to_str(g->build_mode));
     buf_appendf(contents, "pub const link_libc = %s;\n", bool_to_str(g->libc_link_lib != nullptr));
+    buf_appendf(contents, "pub const have_error_return_tracing = %s;\n", bool_to_str(g->have_err_ret_tracing));
 
     buf_appendf(contents, "pub const __zig_test_fn_slice = {}; // overwritten later\n");
 
diff --git a/std/special/panic.zig b/std/special/panic.zig
index 690c4afa1c..d26166fdac 100644
--- a/std/special/panic.zig
+++ b/std/special/panic.zig
@@ -13,10 +13,12 @@ pub coldcc fn panic(msg: []const u8, error_return_trace: ?&builtin.StackTrace) -
             while (true) {}
         },
         else => {
-            if (error_return_trace) |trace| {
-                std.debug.warn("{}\n", msg);
-                std.debug.dumpStackTrace(trace);
-                @import("std").debug.panic("");
+            if (builtin.have_error_return_tracing) {
+                if (error_return_trace) |trace| {
+                    std.debug.warn("{}\n", msg);
+                    std.debug.dumpStackTrace(trace);
+                    @import("std").debug.panic("");
+                }
             }
             @import("std").debug.panic("{}", msg);
         },