--- /dev/null
+++ Libc/Libc-1272.200.26/tests/backtrace.c
@@ -0,0 +1,151 @@
+#include <darwintest.h>
+#include <dlfcn.h>
+#include <execinfo.h>
+#include <mach-o/dyld_priv.h>
+#include <stdbool.h>
+#include <stdlib.h>
+#include <uuid/uuid.h>
+
+
+#define MAX_FRAMES 32
+static const int expected_nframes = 20;
+
+static void *observed_bt[MAX_FRAMES] = {};
+static int observed_nframes = 0;
+static unsigned int save_fp_at_nframes = 0;
+static void *save_fp = NULL;
+
+static int __attribute__((noinline,not_tail_called,disable_tail_calls))
+recurse_a(unsigned int frames);
+static int __attribute__((noinline,not_tail_called,disable_tail_calls))
+recurse_b(unsigned int frames);
+
+static int __attribute__((noinline,not_tail_called,disable_tail_calls))
+recurse_a(unsigned int frames)
+{
+	if (frames == 1) {
+		if (save_fp_at_nframes > 0) {
+			observed_nframes = backtrace_from_fp(save_fp, observed_bt,
+					MAX_FRAMES);
+		} else {
+			observed_nframes = backtrace(observed_bt, MAX_FRAMES);
+		}
+		return 0;
+	} else if (frames == save_fp_at_nframes) {
+		save_fp = __builtin_frame_address(0);
+	}
+
+	return recurse_b(frames - 1);
+}
+
+static int __attribute__((noinline,not_tail_called,disable_tail_calls))
+recurse_b(unsigned int frames)
+{
+	if (frames == 1) {
+		if (save_fp_at_nframes > 0) {
+			observed_nframes = backtrace_from_fp(save_fp, observed_bt,
+					MAX_FRAMES);
+		} else {
+			observed_nframes = backtrace(observed_bt, MAX_FRAMES);
+		}
+		return 0;
+	} else if (frames == save_fp_at_nframes) {
+		save_fp = __builtin_frame_address(0);
+	}
+
+	return recurse_a(frames - 1);
+}
+
+static void __attribute__((noinline,not_tail_called,disable_tail_calls))
+setup_and_backtrace(unsigned int nframes, unsigned int skip_nframes)
+{
+	save_fp_at_nframes = skip_nframes ? skip_nframes - 1 : 0;
+	recurse_a(nframes - 1);
+}
+
+static bool
+check_for_setup(int i, struct dl_info *info)
+{
+	int ret = dladdr(observed_bt[i], info);
+	T_QUIET; T_ASSERT_POSIX_SUCCESS(ret, "dladdr(%p)", observed_bt[i]);
+	void *setup_fp = (void *)&setup_and_backtrace;
+	return info->dli_saddr == setup_fp;
+}
+
+static void __attribute__((noinline))
+expect_backtrace(void)
+{
+	void *recurse_a_fp = (void *)&recurse_a;
+	void *recurse_b_fp = (void *)&recurse_b;
+
+	void *tmp_backtrace[MAX_FRAMES];
+	const int observed_existing_nframes = backtrace(tmp_backtrace, MAX_FRAMES);
+
+	T_EXPECT_EQ(expected_nframes,
+			observed_nframes - observed_existing_nframes,
+			"number of frames traced matches");
+	bool expect_a = true;
+	bool found_setup = false;
+
+	for (int i = 0; i < observed_nframes; i++) {
+		struct dl_info info;
+		if (check_for_setup(i, &info)) {
+			found_setup = true;
+			break;
+		}
+
+		void *expected_saddr = expect_a ? recurse_a_fp : recurse_b_fp;
+		void *observed_saddr = info.dli_saddr;
+		T_EXPECT_GE(observed_saddr, expected_saddr,
+				"frame %d (%p) matches", i, observed_bt[i]);
+		expect_a = !expect_a;
+	}
+
+	T_EXPECT_TRUE(found_setup, "should have found the setup frame");
+}
+
+T_DECL(backtrace, "ensure backtrace(3) gives the correct backtrace")
+{
+	setup_and_backtrace(expected_nframes, 0);
+	expect_backtrace();
+}
+
+T_DECL(backtrace_from_fp,
+		"ensure backtrace_from_fp(3) starts from the correct frame")
+{
+	const int skip_nframes = 5;
+	setup_and_backtrace(expected_nframes + skip_nframes, skip_nframes);
+	expect_backtrace();
+}
+
+T_DECL(backtrace_image_offsets,
+		"ensure backtrace_image_offsets(3) provides valid UUIDs and offsets")
+{
+	setup_and_backtrace(expected_nframes, 0);
+	struct image_offset imgoffs[observed_nframes];
+	backtrace_image_offsets(observed_bt, imgoffs, observed_nframes);
+
+	bool found_setup = false;
+
+	for (int i = 0; i < observed_nframes; i++) {
+		struct dl_info info;
+		if (check_for_setup(i, &info)) {
+			found_setup = true;
+			break;
+		}
+
+		const struct mach_header *mh =
+				dyld_image_header_containing_address(observed_bt[i]);
+
+		uuid_t expected_uuid;
+		bool got_uuid = _dyld_get_image_uuid(mh, expected_uuid);
+		T_QUIET; T_ASSERT_TRUE(got_uuid, "got UUID for Mach-O header");
+
+		T_EXPECT_EQ(uuid_compare(expected_uuid, imgoffs[i].uuid), 0,
+				"frame %d's UUID matches", i);
+		T_EXPECT_EQ((uintptr_t)observed_bt[i] - (uintptr_t)info.dli_fbase,
+				(uintptr_t)imgoffs[i].offset, "frame %d's offset matches", i);
+	}
+
+	T_EXPECT_TRUE(found_setup, "should have found the setup frame");
+}