[PATCH 04/17] gdb: move parser output post-processing to a script

[simon.marchi@polymtl.ca]

From: Simon Marchi <simon.marchi@efficios.com>

The output of bison and flex needs some post-processing before being
compiled.  It is currently done by a sed invocation inlined in each of the
two pattern rules, which is kind of hard to read and modify.  Additionally,
a following patch adds the generation of header files for parsers, and
those will need the same post processing.  Moving the code to a dedicated
script makes re-use easier.

Move the code to post-process-parser-output.sh, which takes the name of the
parser generator (flex or bison), just to know which substitutions to do,
as well as the name of the parser file.

Make the Makefile rules depend on the script, so that the parsers are
regenerated when it changes.

Change-Id: I15f43184034aff33d242052db79586980ec2dac0
---
 gdb/Makefile.in                   | 39 +++++-------------
 gdb/post-process-parser-output.sh | 67 +++++++++++++++++++++++++++++++
 2 files changed, 78 insertions(+), 28 deletions(-)
 create mode 100755 gdb/post-process-parser-output.sh

diff --git a/gdb/Makefile.in b/gdb/Makefile.in
index aeafb9394d7b..80b2f8573294 100644
--- a/gdb/Makefile.in
+++ b/gdb/Makefile.in
@@ -2693,39 +2693,22 @@ po/$(PACKAGE).pot: force
 %.c: %.y
 %.c: %.l
 
-%-gen.c: %.y
+# Post-process a file produced by a parser generator, see the script
+# for details.
+POST_PROCESS_PARSER_OUTPUT_SH = $(srcdir)/post-process-parser-output.sh
+POST_PROCESS_PARSER_OUTPUT = $(SHELL) $(POST_PROCESS_PARSER_OUTPUT_SH)
+
+%-gen.c: %.y $(POST_PROCESS_PARSER_OUTPUT_SH)
 	$(ECHO_YACC) $(SHELL) $(YLWRAP) $< y.tab.c $@.tmp -- \
 		$(YACC) $(YFLAGS) || (rm -f $@.tmp; false)
-	@sed -e '/extern.*malloc/d' \
-	     -e '/extern.*realloc/d' \
-	     -e '/extern.*free/d' \
-	     -e '/include.*malloc.h/d' \
-	     -e 's/\([^x]\)malloc/\1xmalloc/g' \
-	     -e 's/\([^x]\)realloc/\1xrealloc/g' \
-	     -e 's/\([ \t;,(]\)free\([ \t]*[&(),]\)/\1xfree\2/g' \
-	     -e 's/\([ \t;,(]\)free$$/\1xfree/g' \
-	     -e '/^#line.*y.tab.c/d' \
-	     -e 's/YY_NULL/YY_NULLPTR/g' \
-	     -e "s/YYSTYPE/$(subst -,_,$*)_YYSTYPE/g" \
-	     -e "s/yyalloc/$(subst -,_,$*)_yyalloc/g" \
-	     -e "s/yysymbol_kind_t/$(subst -,_,$*)_yysymbol_kind_t/g" \
-	  < $@.tmp > $@.new && \
+	@$(POST_PROCESS_PARSER_OUTPUT) bison $* < $@.tmp > $@.new && \
 	  rm -f $@.tmp && \
 	  mv $@.new $@
-%-gen.c: %.l
+%-gen.c: %.l $(POST_PROCESS_PARSER_OUTPUT_SH)
 	$(ECHO_LEX) $(FLEX) -t $< > $@.tmp || (rm -f $@.tmp; false)
-	@sed -e '/extern.*malloc/d' \
-	     -e '/extern.*realloc/d' \
-	     -e '/extern.*free/d' \
-	     -e '/include.*malloc.h/d' \
-	     -e 's/\([^x]\)malloc/\1xmalloc/g' \
-	     -e 's/\([^x]\)realloc/\1xrealloc/g' \
-	     -e 's/\([ \t;,(]\)free\([ \t]*[&(),]\)/\1xfree\2/g' \
-	     -e 's/\([ \t;,(]\)free$$/\1xfree/g' \
-	     -e 's/yy_flex_xrealloc/yyxrealloc/g' \
-	     < $@.tmp > $@.new && \
-	     rm -f $@.tmp && \
-	     mv $@.new $@
+	@$(POST_PROCESS_PARSER_OUTPUT) flex $* < $@.tmp > $@.new && \
+	  rm -f $@.tmp && \
+	  mv $@.new $@
 
 # XML rules
 
diff --git a/gdb/post-process-parser-output.sh b/gdb/post-process-parser-output.sh
new file mode 100755
index 000000000000..b246e63ddff1
--- /dev/null
+++ b/gdb/post-process-parser-output.sh
@@ -0,0 +1,67 @@
+#!/bin/sh
+
+# Copyright (C) 2026 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/>.
+
+# Post-process a file produced by flex or bison/byacc, reading it from
+# standard input and writing the result to standard output.
+#
+# Usage:
+#
+#    ./post-process-parser-output.sh GENERATOR NAME < INPUT > OUTPUT
+#
+# Where GENERATOR is "bison" (regardless of whether we're using the actual
+# bison or byacc) or "flex", and NAME is the name of the parser (e.g.
+# "cp-name-parser"), used to make the global symbols names bison produces
+# unique.
+
+set -e
+
+generator="$1"
+
+# Convert e.g. "cp-name-parser" to "cp_name_parser".
+name=$(echo "$2" | sed -e 's/-/_/g')
+
+common='
+/extern.*malloc/d
+/extern.*realloc/d
+/extern.*free/d
+/include.*malloc.h/d
+s/\([^x]\)malloc/\1xmalloc/g
+s/\([^x]\)realloc/\1xrealloc/g
+s/\([ \t;,(]\)free\([ \t]*[&(),]\)/\1xfree\2/g
+s/\([ \t;,(]\)free$/\1xfree/g
+'
+
+case "$generator" in
+    bison)
+	sed -e "$common" \
+	    -e '/^#line.*y.tab.c/d' \
+	    -e 's/YY_NULL/YY_NULLPTR/g' \
+	    -e "s/YYSTYPE/${name}_YYSTYPE/g" \
+	    -e "s/yyalloc/${name}_yyalloc/g" \
+	    -e "s/yysymbol_kind_t/${name}_yysymbol_kind_t/g"
+	;;
+    flex)
+	sed -e "$common" \
+	    -e 's/yy_flex_xrealloc/yyxrealloc/g'
+	;;
+    *)
+	echo "$0: unknown parser generator \"$generator\"" >&2
+	exit 1
+	;;
+esac
-- 
2.55.0