gdb: add make-init-c script

I would like to modify how the init.c file is generated (its content).
But as it is, a shell script with multiple sed invocations in a Makefile
target, it's not very maintainable.  Replace that with a shell script
that does the same, but in a more readable way.

The Makefile rule uses the "-" prefix in front of the for loop, I
presume to ignore any error coming from the fact that xml-builtin.c and
cp-name-parser.c are not found in the srcdir (they are generated source
files).  I prefer not to blindly ignore errors, so filter these files
out of INIT_FILES instead (we already filter out other files).

There are no expected meaningful changes to the generated init.c file.
Just the _initialize_all_file declaration that is moved down and "void"
in parenthesis that is removed.

The new regular expression is a bit tighter than the existing one, it
requires the init function to be followed by exactly ` ()`.  Update
bpf-tdep.c accordingly.

gdb/ChangeLog:

	* Makefile.in (INIT_FILES_FILTER_OUT): New.
	(INIT_FILES): Use INIT_FILES_FILTER_OUT.
	(stamp-init): Use make-init-c.
	* bpf-tdep.c (_initialize_bpf_tdep): Remove "void".
	* silent-rules.mk (ECHO_INIT_C): Change.
	* make-init-c: New file.

Change-Id: I6d6b12cbccf24ab79d1219bff05df01624c684f9

1 files changed, 57 insertions, 0 deletions

diff --git a/gdb/make-init-c b/gdb/make-init-c
new file mode 100755
index 0000000..1588760
--- /dev/null
+++ b/gdb/make-init-c
@@ -0,0 +1,57 @@
+#!/usr/bin/env sh
+
+# Copyright (C) 2013-2021 Free Software Foundation, Inc.
+#
+# This file is part of GDB.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+# Generate the init.c source file.
+#
+# Usage:
+#
+#    ./make-init-c source-files > init.c-tmp
+#
+# Where SOURCE-FILES is the list of source files to extract init functions from.
+#
+# Formatting conventions:  The name of the initialization routines must begin
+# with `_initialize_`, must start in column zero, and be followed with exactly
+# ` ()`.  For example:
+#
+# void
+# _initialize_foo ()
+# {
+#   ...
+# }
+#
+
+# Abort on command error.
+set -e
+
+echo "/* Do not modify this file.  */"
+echo "/* It is created automatically by the Makefile.  */"
+echo "#include \"defs.h\"      /* For initialize_file_ftype.  */"
+echo ""
+sed -n -e 's/^\(_initialize_[a-zA-Z0-9_]*\) ()$/\1/p' "$@" | while read -r name; do
+  echo "extern initialize_file_ftype $name;"
+done
+echo ""
+echo "void initialize_all_files ();"
+echo "void"
+echo "initialize_all_files ()"
+echo "{"
+sed -n -e 's/^\(_initialize_[a-zA-Z0-9_]*\) ()$/\1/p' "$@" | while read -r name; do
+  echo "  $name ();"
+done
+echo "}"