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view lwlink/main.c @ 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 | 221b5f58d8ad |
children | b138b4005125 |
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/* main.c Copyright © 2009 William Astle This file is part of LWLINK. LWLINK 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/>. Implements the program startup code */ #include <errno.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #include <lw_cmdline.h> #include <lw_version.h> #include "lwlink.h" #ifdef _MSC_VER #include <lw_win.h> // windows build #else #include <unistd.h> #endif char *program_name; // command line option handling #define PROGVER "lwlink from " PACKAGE_STRING static int parse_opts(int key, char *arg, void *state) { switch (key) { case 'o': // output outfile = arg; break; case 's': // script file scriptfile = arg; break; case 'd': // debug debug_level++; break; case 'e': // entry symbol entrysym = arg; break; case 'b': // decb output outformat = OUTPUT_DECB; break; case 'r': // raw binary output outformat = OUTPUT_RAW; break; case 'f': // output format if (!strcasecmp(arg, "decb")) outformat = OUTPUT_DECB; else if (!strcasecmp(arg, "raw")) outformat = OUTPUT_RAW; else if (!strcasecmp(arg, "lwex0") || !strcasecmp(arg, "lwex")) outformat = OUTPUT_LWEX0; else if (!strcasecmp(arg, "os9")) outformat = OUTPUT_OS9; else if (!strcasecmp(arg, "srec")) outformat = OUTPUT_SREC; else { fprintf(stderr, "Invalid output format: %s\n", arg); exit(1); } break; case lw_cmdline_key_end: // done; sanity check if (!outfile) outfile = "a.out"; break; case 'l': add_input_library(arg); break; case 'L': add_library_search(arg); break; case 0x100: add_section_base(arg); break; case 0x101: sysroot = arg; break; case 'm': map_file = arg; break; case lw_cmdline_key_arg: add_input_file(arg); break; default: return lw_cmdline_err_unknown; } return 0; } static struct lw_cmdline_options options[] = { { "output", 'o', "FILE", 0, "Output to FILE"}, { "debug", 'd', 0, 0, "Set debug mode"}, { "format", 'f', "TYPE", 0, "Select output format: decb, raw, lwex, os9, srec"}, { "decb", 'b', 0, 0, "Generate DECB .bin format output, equivalent of --format=decb"}, { "raw", 'r', 0, 0, "Generate raw binary format output, equivalent of --format=raw"}, { "script", 's', "FILE", 0, "Specify the linking script (overrides the built in defaults)"}, { "library", 'l', "LIBSPEC", 0, "Read library libLIBSPEC.a from the search path" }, { "library-path", 'L', "DIR", 0, "Add DIR to the library search path" }, { "section-base", 0x100, "SECT=BASE", 0, "Load section SECT at BASE" }, { "entry", 'e', "SYM", 0, "Specify SYM as program entry point" }, { "sysroot", 0x101, "DIR", 0, "Specify the path to replace an initial = with in library paths" }, { "map", 'm', "FILE", 0, "Output informaiton about the link" }, { 0 } }; static struct lw_cmdline_parser cmdline_parser = { options, parse_opts, "INPUTFILE ...", "lwlink, a HD6309 and MC6809 cross-linker", PROGVER }; extern void read_files(void); extern void setup_script(void); extern void resolve_files(void); extern void resolve_sections(void); extern void generate_symbols(void); extern void resolve_references(void); extern void resolve_padding(void); extern void do_output(void); extern void display_map(void); // main function; parse command line, set up assembler state, and run the // assembler on the first file int main(int argc, char **argv) { program_name = argv[0]; lw_cmdline_parse(&cmdline_parser, argc, argv, 0, 0, NULL); if (ninputfiles == 0) { fprintf(stderr, "No input files\n"); exit(1); } unlink(outfile); // handle the linker script setup_script(); // read the input files read_files(); // trace unresolved references and determine which non-forced // objects must be included resolve_files(); // resolve section bases and section order resolve_sections(); // generate symbols generate_symbols(); // resolve incomplete references resolve_references(); // resolve section padding bits resolve_padding(); // do the actual output do_output(); // display/output the link map if (map_file) display_map(); exit(0); }