# egcs Frequently Asked Questions

1. How is egcs be different from gcc2?
2. What is an open development model?
3. Releases and Forking
4. bits/libc-lock.h: No such file or directory
5. `_IO_stdfile_0_lock' was not declared in this scope
6. Problems building the Fortran compiler
7. Problems building on MIPS platforms
8. Problems with exception handling on x86 platforms
9. Bootstrap comparison failures on HPs
10. Bootstrap loops rebuilding cc1 over and over
11. Dynamic linker is unable to find GCC libraries
12. libstdc++/libio tests fail badly with --enable-shared
13. Unable to run the testsuite
14. How to build a cross compiler
15. How to install both gcc2 and egcs
16. Snapshots, how, when, why
17. Problems building Linux kernels
18. Virtual memory exhausted
19. GCC can not find GAS
20. egcs does not work on Red Hat 5.0
21. Unable to bootstrap on x86 Solaris2.{5,6}
22. EGCS with Windows
23. cpp: Usage:... Error
24. EGCS will not build KDE

## How is egcs be different from gcc2?

Six years ago, gcc version 1 had reached a point of stability. For the targets it could support, it worked well. It had limitations inherent in its design that would be difficult to resolve, so a major effort was made and gcc version 2 was the result. When we had gcc2 in a useful state, development efforts on gcc1 stopped and we all concentrated on making gcc2 better than gcc1 could ever be. This is the kind of step forward we want to make with egcs.

In brief, the three biggest differences between egcs and gcc2 are these:

- More rexamination of basic architectual decisions of gcc and an interest in adding new optimizations;
- working with the groups who have fractured out from gcc2 (like the Linux folks, the Intel optimizations folks, Fortran folks) including more front-ends; and finally
- An open development model (see below) for the development process.

These three differences will work together to result in a more useful compiler, a more stable compiler, a central compiler that works for more people, a compiler that generates better code.

There are a lot of exciting compiler optimizations that have come out. We want them in gcc. There are a lot of front ends out there for gcc for languages like Fortran or Pascal. We want them easily installable by users. After six years of working on gcc2, we've come to see problems and limitations in the way gcc is architected; it is time to address these again.

## What is an open development model?

With egcs, we are going to try a bazaar style[1] approach to its development: We're going to be making snapshots publicly available to anyone who wants to try them; we're going to welcome anyone to join the development mailing list. All of the discussions on the development mailing list are available via the web. We're going to be making releases with a much higher frequency than they have been made in the past: We're shooting for three by the end of 1997.

In addition to weekly snapshots of the egcs development sources, we are going to look at making the sources readable from a CVS server by anyone. We want to make it so external maintainers of parts of egcs are able to commit changes to their part of egcs directly into the sources without going through an intermediary.

There have been many potential gcc developers who were not able to participate in gcc development in the past. We these people to help in any way they can; we ultimately want gcc to be the best compiler in the world.

A compiler is a complicated piece of software, there will still be strong central maintainers who will reject patches, who will demand documentation of implementations, and who will keep the level of quality as high as it is today. Code that could use wider testing may be intergrated--code that is simply ill-conceived won't be.

egcs is not the first piece of software to use this open development process; FreeBSD, the Emacs lisp repository, and Linux are a few examples of the bazaar style of development.

With egcs, we will be adding new features and optimizations at a rate that has not been done since the creation of gcc2; these additions will inevitably have a temporarily destabilizing effect. With the help of developers working together with this bazaar style development, the resulting stability and quality levels will be better than we've had before.

> [1] We've been discussing different development models a lot over the past few months. The paper which started all of this introduced two terms: A cathedral development model versus a bazaar development model. The paper is written by Eric S. Raymond, it is called ``The Cathedral and the Bazaar''. The paper is a useful starting point for discussions.

## Releases and Forking?

Some folks have questioned whether or not making releases is consistent with the goals of the egcs project and whether or not making releases is a fork from gcc2.

    The egcs project has several goals, including:

      * Experimenting with a new development model, release process and
      release packaging,

      * Using the new development model to accelerate development of new
      features, optimizations, etc for future inclusion in gcc,

      * Providing high quality releases to the public.

    An egcs release is a copy of the egcs sources that the developers have
    tested and are believed to be suitable for wider scale use and testing.

    Making releases of stable, tested sources is both a goal and a means by
    which we hope to achieve other goals of the egcs project.

    The existence of a stable tested release allows egcs to be more thoroughly
    used and tested by a wider audience than is capable of testing snapshots.
    The expanded audience provides developers with critical feedback in a
    timely manner, which is beneficial to GCC as a whole and is consistent with
    the stated goals of egcs.

    The gcc maintainers are encouraged to migrate tested fixes and new features
    from egcs into gcc at their discretion.  egcs maintainers are willing to
    assist the gcc maintainers as time permits.  egcs periodically merges in
    changes from gcc into the egcs sources.

    What will keep egcs from becoming a fork is cooperation between the
    developers of gcc and egcs.

    We don't see this situation as significantly different than other projects
    that make releases based on some version of the gcc sources (Cygnus, g77,
    etc).  All the code is still available for inclusion in gcc at the discretion
    of the gcc maintainers.

## bits/libc-lock.h: No such file or directory

This entry should be obsolete, egcs should handle these beta versions of glibc2 correctly.

egcs includes a tightly integrated libio and libstdc++ implementation which can cause problems on hosts which have libio integrated into their C library (most notably Linux).

We believe that we've solved the major technical problems for the most common versions of libc found on Linux systems. However, some versions of Linux use pre-release versions of glibc2, which egcs has trouble detecting and correctly handling.

If you're using one of these pre-release versions of glibc2, you may get a message "bits/libc-lock.h: No such file or directory" when building egcs. Unfortunately, to fix this problem you will need to update your C library to glibc2.0.5c.

## `_IO_stdfile_0_lock' was not declared in this scope

If you get this error, it means either egcs incorrectly guessed what version of libc is installed on your linux system, or you incorrectly specified a version of glibc when configuring egcs.

If you did not provide a target name when configuring egcs, then you've found a bug which needs to be reported. If you did provide a target name at configure time, then you should reconfigure without specifying a target name.

## Problems building the Fortran compiler

The Fortran front end can not be built with most vendor compilers; it must be built with gcc. As a result, you may get an error if you do not follow the install instructions carefully.

In particular, instead of using "make" to build egcs, you should use "make bootstrap" if you are building a native compiler or "make cross" if you are building a cross compiler.

It has also been reported that the Fortran compiler can not be built on Red Hat 4.X linux for the Alpha. Fixing this may require upgrading binutils or to Red Hat 5.0; we'll provide more information as it becomes available.

## Problems building on MIPS platforms

egcs requires the use of GAS on all versions of Irix, except Irix 6 due to limitations in older Irix assemblers.

Either of these messages indicates that you are using the MIPS assembler when instead you should be using GAS.

        as0: Error: ./libgcc2.c, line 1:Badly delimited numeric literal
              .4byte $LECIE1-$LSCIE1
        as0: Error: ./libgcc2.c, line 1:malformed statement

        as0: Error: /home/law/egcs_release/gcc/libgcc2.c, line 1:undefined symbol in expression
        .word $LECIE1-$LSCIE1

For Irix 6, you should use the native assembler as GAS is not supported on Irix 6.

## Problems with exception handling on x86 platforms

If you are using the GNU assembler (aka gas) on an x86 platform and exception handling is not working correctly, then odds are you're using a buggy assembler.

We recommend binutils-2.8.1.0.15 or newer.
binutils-2.8.1.0.15 source
binutils-2.8.1.0.15 x86 binary for libc5
binutils-2.8.1.0.15 x86 binary for glibc2 Or, you can try a binutils snapshot; however, be aware that the binutils snapshot is untested and may not work (or even build). Use it at your own risk.

## Bootstrap comparison failures on HPs

If you bootstrap the compiler on hpux10 using the HP assembler instead of gas, every file will fail the comparison test.

The HP asembler inserts timestamps into object files it creates, causing every file to be different. The location of the timestamp varies for each object file, so there's no real way to work around this mis-feature.

Odds are your compiler is fine, but there's no way to be certain.

If you use GAS on HPs, then you will not run into this problem because GAS never inserts timestamps into object files. For this and various other reasons we highly recommend using GAS on HPs.

## Bootstrap loops rebuilding cc1 over and over

When building egcs, the build process loops rebuilding cc1 over and over again. This happens on mips-sgi-irix5.2, and possibly other platforms.

This is probably a bug somewhere in the egcs Makefile. Until we find and fix this bug we recommend you use GNU make instead of vendor supplied make programs.

## Dynamic linker is unable to find GCC libraries

This problem manifests itself by programs not finding shared libraries they depend on when the programs are started. Note this problem often manifests itself with failures in the libio/libstdc++ tests after configuring with --enable-shared and building egcs.

GCC does not specify a runpath so that the dynamic linker can find dynamic libraries at runtime.

The short explaination is that if you always pass a -R option to the linker, then your programs become dependent on directories which may be NFS mounted, and programs may hang unnecessarily when an NFS server goes down.

The problem is not programs that do require the directories; those programs are going to hang no matter what you do. The problem is programs that do not require the directories.

SunOS effectively always passed a -R option for every -L option; this was a bad idea, and so it was removed for Solaris. We should not recreate it.

## Unable to run the testsuite

If you get a message about unable to find "standard.exp" when trying to run the egcs testsuites, then your dejagnu is too old to run the egcs tests. You will need to get a newer version of dejagnu; we've made a dejagnu snapshot available until a new version of dejagnu can be released.

## How to build a cross compiler

Building cross compilers is a rather complex undertaking because they usually need additional software (cross assembler, cross linker, target libraries, target include files, etc).

We recommend reading the crossgcc FAQ for information about building cross compilers.

If you have all the pieces available, then `make cross' should build a cross compiler. `make LANGUAGES="c c++" install'will install the cross compiler.

Note that if you're trying to build a cross compiler in a tree which includes binutils-2.8 in addition to egcs, then you're going to need to make a couple minor tweaks so that the cross assembler, linker and nm utilities will be found.

binutils-2.8 builds those files as gas.new, ld.new and nm.new; egcs gcc looks for them using gas-new, ld-new and nm-new, so you may have to arrange for any symlinks which point to <file>.new to be changed to <file>-new.

## Snapshots, how, when, why

We make snapshots of the egcs sources about once a week; there is no predetermined schedule. These snapshots are intended to give everyone access to work in progress. Any given snapshot may generate incorrect code or even fail to build.

If you plan on downloading and using snapshots, we highly recommend you subscribe to the egcs mailing lists. See mailing lists on the main egcs page for instructions on how to subscribe.

When using the diff files to update from older snapshots to newer snapshots, make sure to use "-E" and "-p" arguments to patch so that empty files are deleted and full pathnames are provided to patch. If your version of patch does not support "-E", you'll need to get a newer version. Also note that you may need autoconf, autoheader and various other programs if you use diff files to update from one snapshot to the next.

## How to install both egcs and gcc2

It may be desirable to install both egcs and gcc2 on the same system. This can be done by using different prefix paths at configure time and a few symlinks.

Basically, configure the two compilers with different --prefix options, then build and install each compiler. Assume you want "gcc" to be the egcs compiler and available in /usr/local/bin; also assume that you want "gcc2" to be the gcc2 compiler and also available in /usr/local/bin.

The easiest way to do this is to configure egcs with --prefix=/usr/local/egcs and gcc2 with --prefix=/usr/local/gcc2. Build and install both compilers. Then make a symlink from /usr/local/bin/gcc to /usr/local/egcs/bin/gcc and from /usr/local/bin/gcc2 to /usr/local/gcc2/bin/gcc. Create similar links for the "g++", "c++" and "g77" compiler drivers.

## Problems building Linux kernels

If you installed a recent binutils/gas snapshot on your Linux system, you may not be able to build the kernel because objdump does not understand the "-k" switch. The solution for this problem is to remove /usr/bin/encaps.

The reason you must remove /usr/bin/encaps is because it is an obsolete program that was part of older binutils distributions; the Linux kernel's Makefile looks for this program to decide if you have an old or a new binutils. Problems occur if you installed a new binutils but haven't removed encaps, because the Makefile thinks you have the old one. So zap it; trust us, you won't miss it.

You may get an internal compiler error compiling process.c in newer versions of the Linux kernel on x86 machines. This is a bug in an asm statement in process.c, not a bug in egcs. XXX How to fix?!?

You may get errors with the X driver of the form

    _X11TransSocketUNIXConnect: Can't connect: errno = 111

It's a kernel bug. The function sys_iopl in arch/i386/kernel/ioport.c does an illegal hack which used to work but is now broken since GCC optimizes more aggressively . The newer 2.1.x kernels already have a fix which should also work in 2.0.32.

## Virtual memory exhausted error

This error means your system ran out of memory; this can happen for large files, particularly when optimizing. If you're getting this error you should consider trying to simplify your files or reducing the optimization level.

Note that using -pedantic or -Wreturn-type can cause an explosion in the amount of memory needed for template-heavy C++ code, such as code that uses STL. Also note that -Wall includes -Wreturn-type, so if you use -Wall you will need to specify -Wno-return-type to turn it off.

## GCC can not find GAS

Some configurations like irix4, irix5, hpux* require the use of the GNU assembler intead of the system assembler. To ensure that egcs finds the GNU assembler, you should configure the GNU assembler with the same --prefix option as you used for egcs. Then build & install the GNU assembler. After the GNU assembler has been installed, proceed with building egcs.

## egcs does not work on Red Hat 5.0

This entry is obsolete with the release of egcs-1.0.1 which should handle Red Hat 5.0 correctly.

egcs-1.0 does not currently work with Red Hat 5.0 on some platforms; we'll update this entry with more information as it becomes available.

You may want to try this proposed patch for Red Hat 5.0. Please let us know if you use this patch and whether or not it works.

## Unable to bootstrap on x86 Solaris 2.{5,6}

This entry is obsolete with the release of egcs-1.0.1 which should handle x86 Solaris systems correctly.

This patch should fix the problem

    Index: t-sol2
    ===================================================================
    RCS file: /cvs/cvsfiles/egcs/gcc/config/i386/t-sol2,v
    retrieving revision 1.2
    diff -c -3 -p -r1.2 t-sol2
    *** t-sol2	1997/09/04 23:54:04	1.2
    --- t-sol2	1997/12/04 07:19:07
    *************** crtn.o: $(srcdir)/config/i386/sol2-cn.as
    *** 31,36 ****
      # to produce a shared library, but since we don't know ahead of time when
      # we will be doing that, we just always use -fPIC when compiling the
      # routines in crtstuff.c.

    ! CRTSTUFF_T_CFLAGS = -fPIC
      TARGET_LIBGCC2_CFLAGS = -fPIC
    --- 31,40 ----
      # to produce a shared library, but since we don't know ahead of time when
      # we will be doing that, we just always use -fPIC when compiling the
      # routines in crtstuff.c.
    + #
    + # We must also enable optimization to avoid having any code appear after
    + # the call & alignment statement, but before we switch back to the
    + # .text section.

    ! CRTSTUFF_T_CFLAGS = -fPIC -O2
      TARGET_LIBGCC2_CFLAGS = -fPIC

## EGCS with Windows

egcs does not currently support windows, either natively or with the cygwin32 dll. However Mumit Khan has been working on supporting Windows with egcs. You should check out his site if you're interested in Windows support. GNU Win32 related projects

## cpp: Usage:... Error

If you get an error like this when building egcs (particularly when building __mulsi3), then you likely have a problem with your environment variables.

    cpp: Usage: /usr/lib/gcc-lib/i586-unknown-linux-gnulibc1/2.7.2.3/cpp
    [switches] input output

First look for an explicit '.' in either LIBRARY_PATH or GCC_EXEC_PREFIX from your environment. If you do not find an explicit '.', look for an empty pathname in those variables. Note that ':' at either the start or end of these variables is an implicit '.' and will cause problems.

## EGCS will not build KDE

Previous versions of g++ accepted (as a GNU extension) constructor-arguments for the objects in an array of objects dynamically allocated with new. Here's an example of this construct:

        struct S { S(int); }
        void f() { new S[3](6); }

However, this construct is not allowed by the ANSI/ISO Standard, and is no longer accepted by g++.

KDE uses such constructs and therefore will not build with egcs; note patches are available to fix KDE.

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Last modified: Jan 2, 1998