bb20339691
The trace formatter, unblocked now that 0057 is fixed. - library/modules/trace.sx: to_string() walks the trace buffer (sx_trace_len / frame_at / truncated) and renders "error return trace ..." with one line per frame; print_current() writes it to stderr (libc write(2, ...)). Frame locations are "<location pending DWARF>" until E3.0 resolves PCs; count + ordering + the overflow note are already meaningful. - Catch-clear timing fix (lowerCatch): move the absorption clear from runCatchBody ENTRY to the handler's non-diverging EXIT (both the pure and value-carrying paths). This reconciles the two PLAN-ERR statements that conflicted — §clear-points "buffer cleared before the catch body" vs §catch-over-or "frames still in the buffer when the body runs". Exit-clear satisfies both: the handler can inspect the trace (trace.print_current() shows the chain), and the buffer is empty once the handler completes. A diverging body (raise/return) keeps/discards on its own path. - examples/243-trace-format.sx: catch handler prints the tag + the 2-frame trace, then shows the buffer is empty after. examples/241 updated: the handler now observes len=2 (was 0 under the buggy entry-clear). Gates: zig build, zig build test, bash tests/run_examples.sh (280 passed; lone failure is the user's uncommitted 213-canonical-map pack WIP).
63 lines
2.6 KiB
Plaintext
63 lines
2.6 KiB
Plaintext
#import "std.sx";
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// =====================================================================
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// trace.sx — error return-trace formatting (ERR step E3.3).
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//
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// Reads the thread-local return-trace buffer (ERR E3.1, populated by the
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// push/clear wiring in E3.2) and renders it. A `raise` / propagating `try`
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// pushes a frame; an absorbing site (`catch` / `or value` / destructure)
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// clears the buffer. So at format time the buffer holds exactly the frames
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// of failures that escaped to where you're formatting — typically inside a
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// `catch` handler (the clear fires when the handler completes, so the body
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// still sees the chain) or the (future) failable-`main` wrapper.
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//
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// Frame resolution: a frame is an opaque u64. Resolving it to `file:line:col`
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// needs DWARF line-info (ERR E3.0), which sx does not emit yet — so for now
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// each frame prints as "<location pending DWARF>". The frame COUNT, ordering,
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// and overflow note are already meaningful; once E3.0 lands, only the
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// per-frame location string changes. (The comptime path — resolving a packed
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// `(func_id, ir_offset)` via the interpreter's IR tables — also lands with the
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// resolver in E3.0/E3.3-full.)
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// =====================================================================
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libc :: #library "c";
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// The error-trace buffer C API (library/vendors/sx_trace_runtime/sx_trace.c),
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// linked in for the JIT and auto-injected for AOT when traces are used.
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sx_trace_len :: () -> u32 #foreign;
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sx_trace_truncated :: () -> u32 #foreign;
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sx_trace_frame_at :: (i: u32) -> u64 #foreign;
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write :: (fd: s32, buf: [*]u8, count: usize) -> isize #foreign libc;
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// Render the current trace buffer to a string (allocated from
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// context.allocator). Empty buffer → "" so callers can cheaply skip output.
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to_string :: () -> string {
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n := sx_trace_len();
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if n == 0 { return ""; }
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result := "error return trace (most recent call last):\n";
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if sx_trace_truncated() != 0 {
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result = concat(result, " ... older frames omitted (buffer full)\n");
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}
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i : u32 = 0;
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while i < n {
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frame := sx_trace_frame_at(i);
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// DWARF (E3.0) will resolve `frame` to file:line:col + function name.
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// Until then the raw frame value is shown (a placeholder, not a PC yet).
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line := format(" frame {}: <location pending DWARF> (raw {})\n", i, xx frame);
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result = concat(result, line);
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i = i + 1;
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}
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result;
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}
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// Write the current trace to stderr (fd 2). No-op when the buffer is empty.
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print_current :: () {
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s := to_string();
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if s.len > 0 {
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write(2, s.ptr, xx s.len);
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}
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}
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