From: Eli Zaretskii <eliz@gnu.org>
Date: Thu, 14 Oct 2021 09:14:14 +0000 (+0300)
Subject: ; * etc/DEBUG: Add a section about debugging native-compilation.
X-Git-Tag: emacs-28.0.90~293
X-Git-Url: http://git.eshelyaron.com/gitweb/?a=commitdiff_plain;h=74deafe9212b3ff085c281eade530b2aaff0e03b;p=emacs.git

; * etc/DEBUG: Add a section about debugging native-compilation.
---

diff --git a/etc/DEBUG b/etc/DEBUG
index fae87261865..a1c06342605 100644
--- a/etc/DEBUG
+++ b/etc/DEBUG
@@ -573,6 +573,28 @@ debugging did not (yet) happen.  Here are some useful techniques for that:
    GET_FROM_IMAGE for displaying an image, etc.  See 'enum it_method' in
    dispextern.h for the full list of values.
 
+** Debugging problems with native-compiled Lisp.
+
+When you encounter problems specific to native-compilation of Lisp, we
+recommend to follow the procedure below to try to identify the cause:
+
+ . Reduce the problematic .el file to the minimum by bisection, and
+   try identifying the function that causes the problem.
+
+ . Reduce the problematic function to the minimal code that still
+   reproduces the problem.
+
+ . Study the problem's artifacts, like Lisp or C backtraces, to try
+   identifying the cause of the problem.
+
+If you cannot figure out the cause for the problem using the above,
+native-compile the problematic file after setting the variable
+'comp-libgccjit-reproducer' to a non-nil value.  That should produce a
+file names ELNFILENAME_libgccjit_repro.c, where ELNFILENAME is the
+name of the problematic .eln file, in the same directory where the
+.eln file is produced.  Then attach that reproducer C file to your bug
+report.
+
 ** Following longjmp call.
 
 Recent versions of glibc (2.4+?) encrypt stored values for setjmp/longjmp which
@@ -875,15 +897,6 @@ It is also useful to look at the corrupted object or data structure in
 a fresh Emacs session and compare its contents with a session that you
 are debugging.
 
-** Debugging problems with non-ASCII characters
-
-If you experience problems which seem to be related to non-ASCII
-characters, such as \201 characters appearing in the buffer or in your
-files, set the variable byte-debug-flag to t.  This causes Emacs to do
-some extra checks, such as look for broken relations between byte and
-character positions in buffers and strings; the resulting diagnostics
-might pinpoint the cause of the problem.
-
 ** Debugging the TTY (non-windowed) version
 
 The most convenient method of debugging the character-terminal display