Initial import

examples/backtrace.c

@@ -0,0 +1,61 @@
+#if 0
+/*─────────────────────────────────────────────────────────────────╗
+│ To the extent possible under law, Justine Tunney has waived      │
+│ all copyright and related or neighboring rights to this file,    │
+│ as it is written in the following disclaimers:                   │
+│   • http://unlicense.org/                                        │
+│   • http://creativecommons.org/publicdomain/zero/1.0/            │
+╚─────────────────────────────────────────────────────────────────*/
+#endif
+#include "libc/calls/calls.h"
+#include "libc/log/log.h"
+#include "libc/mem/mem.h"
+#include "libc/runtime/gc.h"
+#include "libc/runtime/runtime.h"
+#include "libc/runtime/symbols.h"
+#include "libc/stdio/stdio.h"
+
+/*
+
+  Your executables will try to find the addr2line tool, which is needed
+  to decrypt gcc debug information, enabling backtraces like this:
+
+    0x0000000000403a7a: Hello at examples/backtrace.c:31
+    0x0000000000403ac3: World at examples/backtrace.c:38
+    0x0000000000401608: main at examples/backtrace.c:42
+    0x0000000000401379: _start at libc/crt/crt.S:61
+
+  If that doesn't work, then your αcτµαlly pδrταblε εxεcµταblε will use
+  its own builtin fallback solution:
+
+    0000ac2fa7e0 000000403a9b Hello+0x49
+    0000ac2fa7f0 000000403ac4 World+0x22
+    0000ac2fa800 000000401609 main+0x7
+    0000ac2fa810 00000040137a _start+0x63
+
+  This is guaranteed to work if the .com.dbg file can be found.
+  Otherwise it'll print numbers:
+
+    0000268a8390 000000403a90 (null)+0x403a8f
+    0000268a83a0 000000403aef (null)+0x403aee
+    0000268a83b0 0000004015fe (null)+0x4015fd
+    0000268a83c0 00000040137a (null)+0x401379
+
+*/
+
+void hello(void) {
+  gc(malloc(1));
+  backtrace(stdout);
+  setenv("ADDR2LINE", "", true);
+  backtrace(stdout);
+}
+
+void world(void) {
+  gc(malloc(1));
+  hello();
+}
+
+int main(int argc, char *argv[]) {
+  world();
+  return 0;
+}