std: add std.options.debug_stacktrace_kind

[nektro]

given the following test file we can run it with the various option values.

const std = @import("std");

pub const std_options = std.Options{
    .debug_stacktrace_kind = .full,
};

pub fn main() !void {
    foo();
}

fn foo() void {
    bar();
}

fn bar() void {
    qux();
}

fn qux() void {
    lorem();
}

fn lorem() void {
    ipsum();
}

fn ipsum() void {
    @panic("oops!");
}

thread 182792 panic: oops!
/home/meghan/src/zig/test4.zig:28:5: 0x10762c0 in ipsum (test4)
    @panic("oops!");
    ^
/home/meghan/src/zig/test4.zig:24:10: 0x10687e8 in lorem (test4)
    ipsum();
         ^
/home/meghan/src/zig/test4.zig:20:10: 0x1038158 in qux (test4)
    lorem();
         ^
/home/meghan/src/zig/test4.zig:16:8: 0x1036098 in bar (test4)
    qux();
       ^
/home/meghan/src/zig/test4.zig:12:8: 0x1033938 in foo (test4)
    bar();
       ^
/home/meghan/src/zig/test4.zig:8:8: 0x1033928 in main (test4)
    foo();
       ^
/home/meghan/src/zig/lib/std/start.zig:511:37: 0x1033904 in posixCallMainAndExit (test4)
            const result = root.main() catch |err| {
                                    ^
/home/meghan/src/zig/lib/std/start.zig:253:5: 0x1033441 in _start (test4)
    asm volatile (switch (native_arch) {
    ^
???:?:?: 0x0 in ??? (???)
Aborted (core dumped)

thread 182911 panic: oops!
/home/meghan/src/zig/test4.zig:28:5: 0x1073880 in ipsum (test4)
/home/meghan/src/zig/test4.zig:24:10: 0x10660e8 in lorem (test4)
/home/meghan/src/zig/test4.zig:20:10: 0x1037a78 in qux (test4)
/home/meghan/src/zig/test4.zig:16:8: 0x10359b8 in bar (test4)
/home/meghan/src/zig/test4.zig:12:8: 0x1033258 in foo (test4)
/home/meghan/src/zig/test4.zig:8:8: 0x1033248 in main (test4)
/home/meghan/src/zig/lib/std/start.zig:511:37: 0x1033224 in posixCallMainAndExit (test4)
/home/meghan/src/zig/lib/std/start.zig:253:5: 0x1032d61 in _start (test4)
???:?:?: 0x0 in ??? (???)
Aborted (core dumped)

thread 183137 panic: oops!
Aborted (core dumped)

beyond stylistic desires, the various options also have performance and binary size ramifications. .none exits faster not having to inspect the program's debug info and results in a smaller file. however since this does not require the file to be stripped to get the effect, using an external debugger remains totally possible.

-rwxr-xr-x 1 meghan users 2227856 Apr 14 02:01 ./test4-full
-rwxr-xr-x 1 meghan users 2208816 Apr 14 02:03 ./test4-slim
-rwxr-xr-x 1 meghan users 1921440 Apr 14 02:04 ./test4-none

[Khitiara]

a version that prints out stack addresses without needing any debug info (so no file, line, or symbol name info) could be useful too

[nektro]

afaik that's already what happens if you use .full and strip. it will print out the addresses with the line info replaced with ????

[Khitiara]

if you strip debug info then dumpStackTrace prints out a warning and returns early, and writeStackTrace returns error.MissingDebugInfo, though printSourceAtAddress does work for what you describe

[andrewrk]

Thank you. I think it is a good idea. Happy to merge if you:

• rebase on latest master
• rename "kind" to "mode" (Since "mode" applies in fewer places than "kind" it a better name when it can be used)
• expose the enum inside the std.Options namespace
• default to "none" when strip is true
• double check that it still works (test it again) and let me know that you did that

[andrewrk]

Suggested change

	debug_stacktrace_kind: enum { none, slim, full } = .full,
	debug_stacktrace_mode: DebugStacktraceMode = if (builtin.strip) .none else .full,

[scheibo]

Suggested change

	/// 'none': this will print no stack trace. By not inlcuding the stack printer code this option can
	/// 'none': this will print no stack trace. By not including the stack printer code this option can