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Installing GNU CC on VMS

The VMS version of GNU CC is distributed in a backup saveset containing both source code and precompiled binaries.

To install the gcc command so you can use the compiler easily, in the same manner as you use the VMS C compiler, you must install the VMS CLD file for GNU CC as follows.

1.
Define the VMS logical names GNU_CC and GNU_CC_INCLUDE to point to the directories where the GNU CC executables (gcc-cpp.exe,
gcc-cc1.exe, etc.) and the C include files are kept respectively. This should be done with the following commands.

    $ assign /system /translation=concealed -disk:[gcc.] gnu_cc
    $ assign /system /translation=concealed -disk:[gcc.include.]
       gnu_cc_include

Include the appropriate disk and directory names. These commands can be placed in your system startup file so they will be executed whenever the machine is rebooted. You may, if you choose, do this via the GCC_INSTALL.COM script in the [GCC] directory.

2.
Install the GCC command with the following command line.

    $ set command /table=sys$common:[syslib]dcltables \
          -/ output=sys$common:[syslib]dcltables \
          gnu_cc:[000000]gcc
    $ install replace sys$common:[syslib]dcltables

3.
To install the help file, use the following.

    $ library/help sys$library:helplib.hlb gcc.hlp

Now, invoke the compiler with a command like gcc /verbose file.c, which is equivalent to the command gcc -v -c file.c in Unix.

If you wish to use GNU C++ you must first install GNU CC, and then perform the following steps.

1.
Define the VMS logical name GNU_GXX_INCLUDE to point to the directory where the preprocessor will search for the C++ header files. This can be done with the following command.

    $ assign /system /translation=concealed - \
      disk:[ gcc.gxx_include.] gnu_gxx_include

Include the appropriate disk and directory name. If you are going to be using libg++, this is where the libg++ install procedure will install the libg++ header files.

2.
Obtain the file gcc-cc1plus.exe, and place this in the same directory that gcc-cc1.exe is kept. The GNU C++ compiler can be invoked with a command like gcc /plus /verbose file.cc, which is equivalent to the command g++ -v -c file.cc in Unix.

We try to put corresponding binaries and sources on the VMS distribution tape. But sometimes the binaries will be from an older version than the sources, because we dont always have time to update them. (Use the /version option to determine the version number of the binaries and compare it with the source file version.c to tell whether this is so.) In this case, you should use the binaries you get to recompile the sources.

If you must recompile, use the following steps.

1.
Execute the command procedure, vmsconfig.com to set up the files, tm.h, config.h, aux-output.c, and md. , and to create files, tconfig.h and hconfig.h. This procedure also creates several linker option files used by make-cc1.com and a data file used by
make-l2.com.

    $ @vmsconfig.com

2.
Setup the logical names and command tables as defined in Step 1. In addition, define the VMS logical name GNU_BISON to point to the directories where the Bison executable is kept. This should be done with the following command.

    $ assign /system /translation=concealed - \
      disk:[ bison.] gnu_bison

You may, if you choose, use the INSTALL_BISON.COM script in the [BISON] directory.

3.
Install the BISON command with the following command line.

    $ set command /table=sys$common:[syslib]dcltables - \
      /output=sys$common:[syslib]dcltables - \
      gnu_ bison:[000000]bison
    $ install replace sys$common:[syslib]dcltables

4.
Type @make-gcc to recompile everything (alternatively, submit the file make-gcc.com to a batch queue).

If you wish to build the GNU C++ compiler as well as the GNU CC compiler, you must first edit make-gcc.com and follow the instructions that appear in the comments.

5.
In order to use GCC, you need a library of functions which GCC compiled code will call to perform certain tasks, and these functions are defined in the file libgcc2.c.

To compile this you should use the command procedure, make-l2.com, which will generate the library libgcc2.olb.

Build libgcc2.olb using the compiler built from the same distribution that libgcc2.c came from, and make-gcc.com will automatically do all of this for you.

To install the library, use the following commands.

    $ library gnu_cc:[000000]gcclib/delete=(new,eprintf)
    $ library gnu_cc:[000000]gcclib/delete=L_*
    $ library libgcc2/extract=*/output=libgcc2.obj
    $ library gnu_cc:[000000]gcclib libgcc2.obj

The first command simply removes old modules that will be replaced with modules from libgcc2 under different module names. The modules new and eprintf may not actually be present in your gcclib.olb if the VMS librarian complains about those modules not being present, simply ignore the message and continue on with the next command. The second command removes the modules that came from the previous version of the library libgcc2.c.

Whenever you update the compiler on your system, you should also update the library with the previous procedure.

6.
You may wish to build GCC in such a way that no files are written to the directory where the source files reside. An example would be the when the source files are on a read-only disk. In these cases, execute the following DCL commands (substituting your actual path names) where the directory dua1:[gcc.source_dir] contains the source code, and the directory dua0:[gcc.build_dir] is meant to contain all of the generated object files and executables.

    $ assign dua0:[gcc.build_dir.]/translation=concealed, - \
           dua1:[ gcc.source_dir.]/translation=concealed  \
                                  gcc_build
    $ set default gcc_build:[000000]

Once you have done this, you can proceed building GCC as previously described. (Keep in mind that gcc_build is a rooted logical name, and thus the device names in each element of the search list must be an actual physical device name rather than another rooted logical name).

7.
If you are building GNU CC with a previous version of GNU CC, you also should check to see that you have the newest version of the assembler. In particular, GNU CC version 2 treats global constant variables slightly differently from GNU CC version 1, and GAS version 1.38.1 does not have the patches required to work with GCC version 2. If you use GAS 1.38.1, then extern const variables will not have the read-only bit set, and the linker will generate warning messages about mismatched psect attributes for these variables. These warning messages are merely a nuisance, and can safely be ignored.

If you are compiling with a version of GNU CC older than 1.33, specify /DEFINE=(inline=) as an option in all the compilations. This requires editing all the gcc commands in make-cc1.com. (The older versions had problems supporting inline.) Once you have a working 1.33 or newer GNU CC, you can change this file back.

8.
If you want to build GNU CC with the VAX C compiler, you will need to make minor changes in make-cccp.com and make-cc1.com to choose alternate definitions of CC, CFLAGS, and LIBS. See comments in those files. However, you must also have a working version of the GNU assembler (GNU as, also known as GAS) as it is used as the back-end for GNU CC to produce binary object modules and is not included in the GNU CC sources. GAS is also needed to compile libgcc2 in order to build gcclib (see Step 5); make-l2.com expects to be able to find it operational in gnu_cc:[000000]gnu-as.exe.

To use GNU CC on VMS, you need the VMS driver programs gcc.exe, gcc.com, and gcc.cld. They are distributed with the VMS binaries (gcc-vms) rather than the GNU CC sources. GAS is also included in gcc-vms, as is Bison.

Once you have successfully built GNU CC with VAX C, you should use the resulting compiler to rebuild itself.

Before doing this, be sure to restore the CC, CFLAGS, and LIBS definitions in make-cccp.com and make-cc1.com. The second generation compiler will be able to take advantage of many optimizations that must be suppressed when building with other compilers.

Under previous versions of GNU CC, the generated code would occasionally give strange results when linked with the sharable VAXCRTL library. Now this should work.

Even with this version, however, GNU CC itself should not be linked with the sharable VAXCRTL. The version of qsort in VAXCRTL has a bug (known to be present in VMS versions V4.6 through V5.5) which causes the compiler to fail.

The executables are generated by make-cc1.com and make-cccp.com use the object library version of VAXCRTL in order to make use of the qsort routine in gcclib.olb.

If you wish to link the compiler executables with the shareable image version of VAXCRTL, you should edit the file tm.h (created by vmsconfig.com) to define the macro QSORT_WORKAROUND.

QSORT_WORKAROUND is always defined when GNU CC is compiled with VAX C, to avoid a problem in case gcclib.olb is not yet available.