Gpc April 2009

gpc@gnu.de

5 participants
8 discussions

Inefficiency of `mod'
by Emil Jerabek 25 Oct '10

25 Oct '10

Hi, during some debugging I noticed that GPC generates very hairy code for the `mod' operator with signed arguments. A closer look revealed that the code contains a lot of branching on conditions which can be determined on compile time, and most surprisingly, the value of X mod Y is recomputed _twice_, if X is negative. (I've attached a commented assembler dump.) This may be partially a back-end problem (CSE?), but I feel there's something wrong in the relevant code in gpc-common.c (build_pascal_binary_op) as well. `exp1 mod exp2' gets translated into something like exp2 <= 0 ? error : exp1 >= 0 ? exp1 mod exp2 : ((-exp1) mod exp2) == 0 ? 0 : exp2 - (-exp1) mod exp2 This arranges that both arguments supplied to the "internal mod" are non-negative, but this information is not passed on -- the arguments are still declared as signed types, which apparently makes the back-end to produce the mess it does. I've done a little test: the following replacement for `mod', which differs from the built-in one essentially just by the type-casts to `Cardinal', inline operator xmod (X, Y: Integer) = Z: Integer; begin if Y <= 0 then RuntimeError (714); if X >= 0 then Z := Cardinal (X) mod Y else begin Z := Cardinal (-X) mod Y; if Z <> 0 then Z := Y - Z end end; indeed generates a better code, it measures about 15% faster for positive X and more than twice faster for negative X. YMMV. If this is possible in user code, it should work in the compiler internals as well :) The result type of the whole `mod' expression looks dubious too. IIUIC, `exp1 mod exp2' inherits the type of exp1. Now, the result of `mod' is guaranteed to be nonnegative and to fit in the type of exp2 (or more precisely, it is in 0 .. High (type of (exp2)) - 1), whereas it needn't have anything to do with the type of exp1: consider var X, Z: Integer; Y: LongInt; begin X := -8; Y := High (LongInt); Z := X mod Y { -> overflow } end Or am I missing something? Emil (BTW, where is fjf434c.pas?)

10 16

GPC support for AIX 6?
by Gert Doering 16 Feb '10

16 Feb '10

Hi Gnu Pascal list, we're currently using IBM's xpc pascal compiler on IBM AIX 5.3. New machines are being shipped with AIX 6, and IBM's xpc is no longer supported there - for the time being, it actuall works (the xpc frontend generated intermediate code, and the second stage compiler still groks it). Management is not happy about this, as it might break any day, and I have been asked to "provide GPC" on AIX 6. Googling seems to suggest that the earliest release of GCC to work on AIX 6 is gcc 4.2.4 This mailing list's archive suggests that GPC and GCC 4.2 do not yet work together, due to larger efforts required due to backend changes (Waldek's mail from March 12, 2008). I reported this to management ("there is no GPC on AIX 6"), and they came back with the question "if we pay one of the GPC developers to do a GPC port to a recent GCC, to support AIX 6, how much would that cost?". Here we go - I'm posing this question to you. Is one of you capable and willing to make GPC work on AIX 6? And if yes, what would your conditions be (estimated time to do this, estimated costs)? (I can't promise anything, but will report back to management and they will decide...) thanks, gert -- Gert Doering gd(a)medat.de MEDAT Muenchen Tel: 089/126808-0 Fax: -50

7 13

New (gpc-20060325)
by Waldek Hebisch 08 Dec '09

08 Dec '09

I have put a new gpc snapshot at: http://www.math.uni.wroc.pl/~hebisch/gpc-20060325.tar.bz2 Main change is preliminary gcc-4.0.x support. The other changes are rather small. Note that for "production use" 3.4.x and 3.3.x backend are prefered. Also, using 2.8.1, 2.95.3 and 3.2.3 backend should work, but is depreciated. For more detail see: http://www.math.uni.wroc.pl/~hebisch/gpc/NEWS-20060325 and http://www.math.uni.wroc.pl/~hebisch/gpc/Fixed-20060325 -- Waldek Hebisch hebisch(a)math.uni.wroc.pl

7 44

Aborting compilation
by Pascal Viandier 30 Apr '09

30 Apr '09

Hi all, Is there a gpc directive that can issue a message and then abort the compilation? I tried {$M ...} but it does not stop the compilation process. My goal is to prohibit the use of FillChar() in our code by stopping the compilation when the compiler finds one. I used a macro that redefines FillChar(a,b,c); as {$M ERROR: Fillchar use is not allowed!} but this does not seem sufficient to prevent its usage and its destructive effect on strings :-( If there is no such compiler directive, any other suggestion is welcome. Regards Pascal Viandier

2 2

[Fwd: GCC 4.4.0 Released]
by Adriaan van Os 23 Apr '09

23 Apr '09

-------- Original Message -------- Subject: GCC 4.4.0 Released Date: Thu, 23 Apr 2009 09:12:30 +0200 From: Jakub Jelinek <jakub(a)redhat.com> Reply-To: Jakub Jelinek <jakub(a)redhat.com> To: gcc-announce(a)gcc.gnu.org, gcc(a)gcc.gnu.org The GNU Compiler Collection version 4.4.0 has been released. GCC 4.4.0 is a major release, containing substantial new functionality not available in GCC 4.3.x or previous GCC releases. See: http://gcc.gnu.org/gcc-4.4/changes.html for more information about changes in GCC 4.4.0. This release is available from the FTP servers listed here: http://www.gnu.org/order/ftp.html The release is in gcc/gcc-4.4.0/ subdirectory. If you encounter difficulties using GCC 4.4, please do not contact me directly. Instead, please visit http://gcc.gnu.org for information about getting help. As always, a vast number of people contributed to this GCC releases -- far too many to thank individually!

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Re: Stupid Installation Question
by John L. Ries 19 Apr '09

19 Apr '09

Wasn't aware that someone had GPC working with the GCC 4 back end, but I'm happy to hear it (must not have been paying enough attention to the list). Anyway, I now have a working GPC on my laptop and I have verified that my existing GCC (4.2.3) still works. Thanks to both you and the Chief for your help. --------------------------| John L. Ries | Salford Systems | Phone: (619)543-8880 x107 | or (435)867-8885 | --------------------------| On Sun, 19 Apr 2009, Yahoo - Christopher Butler wrote: > John L. Ries wrote: >> How does one go about compiling and installing GPC under Linux in such >> a way as to not interfere with the GCC 4 one already has? I've ended >> up installing and ripping out GPC on the Linux side on three different >> occasions (always Slackware) because I was no longer able to use GCC 4 >> (as much as I hate C, it is useful to have a C compiler around for >> compiling free software). Seems that the GCC 3 libraries GPC needs >> end up pre-empting the GCC 4 libraries. If people need exact error >> messages, I can go ahead and redo the install, so I can remember what >> they are (it's been a while). >> >> I did recently install that other free Pascal compiler, only to >> discover that it wouldn't compile my nearly completed project from 5 >> years ago (not even my Borland-style units), so I really would like to >> have GPC back on my Linux boxes without the hassle of changing distros. >> >> BTW: As much as I appreciate Kevan Hashemi's making a pre-compiled >> Linux GPC binary available, my preference would be for a 64-bit build. >> >> --------------------------| >> John L. Ries | >> Salford Systems | >> Phone: (619)543-8880 x107 | >> or (435)867-8885 | >> --------------------------| >> > > John > > In response to your email below is exactly what I do to install GPC on > Fedora 9 32 Linux. > > Download the following files to your home directory:- > > GCC > > http://ftp.gnu.org/gnu/gcc/gcc-4.1.2/gcc-4.1.2.tar.bz2 > > Or > > ftp://ftp.gnu.org/gnu/gcc/gcc-4.1.2/gcc-4.1.2.tar.bz2 > > GPC > > http://www.math.uni.wroc.pl/~hebisch/gpc/gpc-20070904.tar.bz2 > > ***** Commands should be typed exactly ***** > > mkdir src > mkdir src/build > > tar -xf gcc-4.1.2.tar.bz2 -C src > > tar -xf gpc-20070904.tar.bz2 -C src > > cd src/gpc-20070904/ > > cp -Rp ../gcc-4.1.2/gcc > > cd ../build > > ../gcc-4.1.2/configure --prefix=/usr/local/gpc --program-suffix=-4.1.2 > --enable-debug --enable-languages=c,pascal > > make DEBUG=1 > > ***** After compiling become Root and install ***** > > make install > > cd /usr/local/bin > ln -sf ../gpc/bin/gpc-4.1.2 gpc > ln -sf ../gpc/bin/gpc-run gpc-run > ln -sf ../gpc/bin/gpidump gpidump > ln -sf ../gpc/bin/binobj binobj > > I hope this has been useful and wish you the best of luck. > > As regards of GPC on Linux 64 bit machine, you will have to rewrite GPC. > > Chris > > > > > >

1 0

Stupid Installation Question
by John L. Ries 19 Apr '09

19 Apr '09

How does one go about compiling and installing GPC under Linux in such a way as to not interfere with the GCC 4 one already has? I've ended up installing and ripping out GPC on the Linux side on three different occasions (always Slackware) because I was no longer able to use GCC 4 (as much as I hate C, it is useful to have a C compiler around for compiling free software). Seems that the GCC 3 libraries GPC needs end up pre-empting the GCC 4 libraries. If people need exact error messages, I can go ahead and redo the install, so I can remember what they are (it's been a while). I did recently install that other free Pascal compiler, only to discover that it wouldn't compile my nearly completed project from 5 years ago (not even my Borland-style units), so I really would like to have GPC back on my Linux boxes without the hassle of changing distros. BTW: As much as I appreciate Kevan Hashemi's making a pre-compiled Linux GPC binary available, my preference would be for a 64-bit build. --------------------------| John L. Ries | Salford Systems | Phone: (619)543-8880 x107 | or (435)867-8885 | --------------------------|

2 2

Stupid Installation Question # 2
by John L. Ries 19 Apr '09

19 Apr '09

Probably related to the first. I notice that Gentoo masks its GPC e-build. Are there any precautions to be observed when unmasking it so it can be installed? --------------------------| John L. Ries | Salford Systems | Phone: (619)543-8880 x107 | or (435)867-8885 | --------------------------|

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Gpc April 2009