view extra/as @ 418:3832a68d83ef

Fix internal compiler error on "var2 = var1 + 1" patterns This appears to be the correct fix. It was provided by Tormod Volden (debian.tormod@gmail.com). The final commit is substantially different from Tormod's submission mostly due to housecleaning (removing the old patches and updating the README). Tormod's comments follow. The original addhi_mem_1 "insn" instruction pattern /matches/ two memory operands, just with the /constraint/ that these are the same location. A pattern match tells the compiler "you should be able to use this, but you might have to work on it to meet the constraints". For typical constraints on registers the compiler can add "reloads", moving stuff between registers or from memory, until the constraints are met and the instruction can be used. However, in this case, no amount of reloads can make two memory locations the same if they already weren't, so the compiler breaks down and cries "unable to generate reloads". It seems this issue only appears if optimization is enabled. The proof is in gcc's reload.c and is left as an exercise to the reader. Limiting the matching pattern to identical memory operands avoids these situations, while allowing the common "var++" cases. References: The pattern/constraints difference is explained in https://gcc.gnu.org/onlinedocs/gccint/Simple-Constraints.html#index-other-register-constraints-3335
author William Astle <lost@l-w.ca>
date Tue, 29 Mar 2016 21:21:49 -0600
parents f5a88f147fae
children c41d72a58ef6
line wrap: on
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#!/bin/sh
#
# Copyright 2009 by William Astle <lost@l-w.ca>
#
#This file is part of LWASM.
#
#LWASM 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/>.

# this was based somewhat on the "as" script from gcc6809

#echo "LWASM-as $0 $*"

show_version () {
cat <<END
LWASM (GNU assembler frontend) 2.3
This program is free software; you may redistribute it under the terms of
the GNU General Public License.  This program has absolutely no warranty.
END
}

fatal_error () {
	echo $* 1>&2
	exit 1
}

# Assume nothing.

input_file=
output_file=
list_file=
options=
list_file_enabled=n

# Parse the command-line options.  See the GNU 'as' man page for
# an explanation of all these options.  Our goal is to translate
# them into lwasm form.

while [ "$1" != "" ]; do
	arg=$1; shift
	case $arg in
		-m6809)
			true
			;;
		-gn)
			# Generate NoICE debug symbols
			# ignored - no output formats support debugging symbols
			;;
		-gs)
			# Generate SDCC debug symbols
			# ignored - no output formats supprt debugging symbols
			;;
#		--globalize-symbols)
#			# Make all symbols global
#			# lwasm does not support globalizing everything by default
#			;;
		-m*)
			fatal_error "invalid CPU option '$arg'"
			;;
		--)
			fatal_error "standard input not supported"
			;;
#		-a*)
#			options="${options}lc"
#			list_file_enabled=y
#			;;
		-I*)
			#include_file=${arg#-I}
			#echo "warning: include path '$include_file' ignored"
			;;
		-MD)
			fatal_error "assembler option '$arg' not supported"
			;;
		-o)
			output_file=$1; shift
			;;
		-v|-version)
			show_version
			;;
		--version)
			show_version
			exit 0
			;;
		-D|-f|-K|--traditional-format|-w|-x|-Z|-W|--no-warn)
			# These options are accepted but ignored by GNU as.
			true
			;;
#		=*)
#			# Set the name of the listing file
#			list_file=${arg#=}
#			;;
		-Qy)
			# "identify in output" - ignore
			true
			;;
		-*)
			echo "as (m6809): unrecognized option $arg"
			exit 1
			;;
		*)
			input_file=$arg
			;;
	esac
done

# Complain if no input files given.  We don't support redirecting
# from standard input.

if [ "x$input_file" = "x" ]; then
	fatal_error "no input file specified"
fi

# Invoke the real (lwasm) assembler.
# The -o option specifies the output file name
# --obj creates object files
# --pragma=undefextern causes undefined symbols to be assumed external
# --pragma=cescapes allows C escape syntax in strings
#echo lwasm -o "$output_file" $options --obj --pragma=undefextern --pragma=cescapes $input_file
# pragma=newsource allows preprocessed asm files with macro expansion to assemble properly even
# when the preprocessor interproses extra spaces
lwasm -o "$output_file" $options --obj --pragma=undefextern --pragma=cescapes --pragma=importundefexport --pragma=newsource $input_file
rc=$?

# OK, see if the assembler succeeded or not.
# If it failed, the source is copied to /tmp/as6809_error.s
# so that it can be inspected.  GCC will normally delete any
# temporary .s files that it generates.  This makes debugging
# the compiler easier.
#
# lwasm does not create an output file if it errors out but it also doesn't
# remove an existing file if it fails so we remove it anyway...

if [ "$rc" != "0" ]; then
	cp -p $input_file /tmp/as6809_error.s
	rm -f $asoutput_file
	exit $rc
fi

# we don't need anything fancy here since lwasm supports specifying output
# file names....