April 2008 - Gpc

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?)

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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

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GPC Home Page
by Kevan Hashemi 30 Apr '08

30 Apr '08

Hi, The following page is top of the list when you Google "GNU Pascal Compiler". http://www.gnu-pascal.de/gpc/h-index.html The copyright on the page has not been updated since 2005. The most recent version of GPC available on the site is 20041017. When I look for GPC, I end up finding it in three different places: one for MacOS (I have 20051116), one for Linux (I use 20041017), and one for Windows (I have 20070904 for MinGW). My cross-platform code has to include compiler directives like this: {$ifdef __GPC_RELEASE__} {$if __GPC_RELEASE__ > 20050000} {$define INIT_CALL '_p__M0_init'} {$else} {$define INIT_CALL 'init_pascal_main_program'} {$endif} {$else} {$define INIT_CALL 'init_pascal_main_program'} {$endif} procedure initialize_main; external name INIT_CALL; Where can I get the latest GPC binaries for MacOS, Linux, and MinGW? If the binaries are not available, where can I download the latest source files? Yours, Kevan -- Kevan Hashemi, Electrical Engineer Physics Department, Brandeis University http://alignment.hep.brandeis.edu/

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Building latest gpc on Intel OS X 10.5.2
by Peter Schorn 28 Apr '08

28 Apr '08

I'm trying to build the latest gpc (gpc-20070904.tar.bz2) with Adriaan's patches on a Macintosh OS X 10.5.2. with Intel. I configure with ../gcc-4.1.2/configure --enable-languages=pascal,c --enable-threads=posix --prefix=/Developer/Pascal/gpc412 but the "make bootstrap" fails with Undefined symbols: "___sysctl", referenced from: ___enable_execute_stack in _enable_execute_stack_s.o ld: symbol(s) not found /usr/bin/libtool: internal link edit command failed make[3]: *** [libgcc_s.dylib] Error 1 make[2]: *** [libgcc.a] Error 2 make[1]: *** [stage1_build] Error 2 make: *** [bootstrap] Error 2 What am I missing? Peter --- peter.schorn(a)acm.org

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compiling static library + gpc runtime without _statvfs on Mac OS X for Intel
by Glenn Howes 20 Apr '08

20 Apr '08

Hello, After months of being distracted by another portion of my application, I'm back to creating a universal binary version of the Pascal based library we are linking into our C++ based application. The problem is the application will not launch under PPC on Mac OS X 10.3 (Panther). The console registers an undefined symbol: _statvfs expected to be defined in /usr/lib/libSystem.B.dylib After some research, I found this call is being used by the StatFS routine implemented in rts.c (line 1510) /** Get information about a file system. */ GLOBAL (Boolean _p_StatFS (char *Path UNUSED, StatFSBuffer *Buf)) { int Result; #ifdef HAVE_STATVFS struct statvfs b; errno = 0; Result = statvfs (Path, &b); Buf->BlockSize = (long long int) b.f_frsize; Buf->BlocksTotal = (long long int) b.f_blocks; Buf->BlocksFree = (long long int) b.f_bavail; Buf->FilesTotal = (int) b.f_files; Buf->FilesFree = (int) b.f_favail; #elif defined (HAVE_STATFS) struct statfs b; errno = 0; Result = statfs (Path, &b); Buf->BlockSize = (long long int) b.f_bsize; Buf->BlocksTotal = (long long int) b.f_blocks; Buf->BlocksFree = (long long int) b.f_bavail; Buf->FilesTotal = (int) b.f_files; Buf->FilesFree = (int) b.f_ffree; #else Result = -1; errno = ENOSYS; #endif if (Result == 0) return True; Buf->BlockSize = 0; Buf->BlocksTotal = 0; Buf->BlocksFree = 0; Buf->FilesTotal = 0; Buf->FilesFree = 0; return False; } It appears to me that HAVE_STATVFS is defined if my current OS X SDK (10.4) has a statvfs.h header file amongst its include files, which means if I build my Pascal development environment from the build-on- Intel.command that the statvfs version will be hard wired into the runtime and any binary I generate will not work on 10.3 (which does not have statvfs in its libSystem.B.dylib library). Also, if I build my environment/library on a PowerPC using the build-on- powerPC-10.3.command, I end up with a different set of link problems involving the long double version of pow(). Besides which, I'd prefer to do my development on OS X for Intel going forward. I have tried hand editing the above routine and rebuilding my Pascal development environment, and pulling the statvfs.h file from my OS X SDK, and yet when my application links, it still has an unresolved reference to _statvfs. I'm not a build engineer, as my previous missives to this mailing list make clear, and I'm at a loss as to how to proceed. Just to be clear, I link in two static libraries: a universal version of the libgpc.a for the runtime, and a universal version of the library I've created. Neither of them contain the symbol _statvfs (at least I can't find that text in them). I link that with my application. The application now references _statvfs (I can now see the text in it's executable). I can't launch on 10.3. I comment out the calls to the Pascal library and recompile+relink, and the application no longer has the symbol and I can launch under 10.3. So something in either of the gpc associated libraries must be calling something which calls statvfs, making the linker (ld) mark statvfs as an unresolved symbol to be loaded in at runtime. At least that is my impression. So, I'd appreciate some suggestions. --glenn

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Updated GPC compiler for Mac OS X
by Adriaan van Os 15 Apr '08

15 Apr '08

Updated GPC sources, patches and binary installers for Mac OS X can be downloaded from <http://www.microbizz.nl/gpc.html>. The source package includes a double-clickable build script. Special thanks to Gale Paeper and Thorsten Lemke for their help. Regards, Adriaan van Os

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Re: GPC compiler bug: functional parameter invocation
by Régis Cridlig 05 Apr '08

05 Apr '08

Thank you, I succeeded in installing the latest cygwin build: gpc-20070904.i686-pc-cygwin.tar.gz This is the compiler version: $ gpc -v Reading specs from /usr/lib/gcc/i686-pc-cygwin/3.4.4/specs Configured with: ../configure --enable-languages=pascal --enable-threads=posix - -with-system-zlib --enable-nls --without-included-gettext --enable-interpreter - -disable-sjlj-exceptions --enable-shared --build=i686-pc-cygwin --host=i686-pc-c ygwin --target=i686-pc-cygwin --enable-haifa --prefix=/usr : (reconfigured) ../c onfigure --enable-languages=pascal --enable-threads=posix --with-system-zlib --e nable-nls --without-included-gettext --enable-interpreter --disable-sjlj-excepti ons --enable-shared --build=i686-pc-cygwin --host=i686-pc-cygwin --target=i686-p c-cygwin --enable-haifa --prefix=/usr Thread model: posix gpc version 20070904, based on gcc-3.4.4 This is the compilation and execution: $ gpc crashes.p -Wall -g -o crashes.exe $ gdb crashes.exe GNU gdb 6.5.50.20060706-cvs (cygwin-special) Copyright (C) 2006 Free Software Foundation, Inc. GDB is free software, covered by the GNU General Public License, and you are welcome to change it and/or distribute copies of it under certain conditions. Type "show copying" to see the conditions. There is absolutely no warranty for GDB. Type "show warranty" for details. This GDB was configured as "i686-pc-cygwin"... (gdb) run Starting program: /cygdrive/c/Documents and Settings/regis.cridlig/My Documents/Info/Pascal/crashes.exe Loaded symbols for /cygdrive/c/WINDOWS/system32/ntdll.dll Loaded symbols for /cygdrive/c/WINDOWS/system32/kernel32.dll Loaded symbols for /usr/bin/cygwin1.dll Loaded symbols for /cygdrive/c/WINDOWS/system32/advapi32.dll Loaded symbols for /cygdrive/c/WINDOWS/system32/rpcrt4.dll Loaded symbols for /cygdrive/c/WINDOWS/system32/secur32.dll Program received signal SIGSEGV, Segmentation fault. 0x0022cc20 in ?? () (gdb) bt #0 0x0022cc20 in ?? () #1 0x004010a9 in _p__M0_S1_Q (J=200, A=@0x22cc20) at crashes.p:16 #2 0x004010c6 in _p__M0_S1_Q (J=100, A=@0x401050) at crashes.p:16 #3 0x004010e2 in _p__M0_main_program () at crashes.p:20 #4 0x0040115b in main (argc=1, argv=0x6927a0, envp=0x690090) at <implicit code>:22 (gdb) The program source: $ cat crashes.p program Crashes(input,output); function B(l:integer):boolean; begin B:=true; end; procedure Q(j:integer;function A(l:integer):boolean); function E(l:integer):boolean; begin E := false end; begin if A(j) then Q(200,E); end; begin Q(100,B); end. What is going wrong? -- Regis 2008/4/4, Prof A Olowofoyeku (The African Chief) <chiefsoft(a)bigfoot.com>: > > On 3 Apr 2008 at 14:25, Régis Cridlig wrote: > > > > > What is the latest stable release of gpc? > > > > http://www.math.uni.wroc.pl/~hebisch/gpc/gpc-20070904.tar.bz2 > > > You can get Cygwin binaries here: > http://gnu-pascal.de/contrib/chief/win32/cygwin/ > > > Best regards, The Chief > -------- > Prof. Abimbola A. Olowofoyeku (The African Chief) > web: http://www.greatchief.plus.com/ > > >

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FPC compiler bug: functional parameter invocation
by Régis Cridlig 04 Apr '08

04 Apr '08

Hello! This short program compiles without a warning, but crashes at execution. The compiler is FPC 2.2 on the win32 platform. program Crashes(input,output); function B(l:integer):boolean; begin B:=true; end; procedure Q(j:integer;function A(l:integer):boolean); function E(l:integer):boolean; begin E := false end; begin if A(j) then Q(200,E); end; begin Q(100,B); end. This is the compiler command: $ gpc --classic-pascal -g -Wall crashes.p Here are the stack frames from gdb: Loaded symbols for /cygdrive/c/WINDOWS/system32/ntdll.dll Loaded symbols for /cygdrive/c/WINDOWS/system32/kernel32.dll Loaded symbols for /usr/bin/cygwin1.dll Loaded symbols for /cygdrive/c/WINDOWS/system32/advapi32.dll Loaded symbols for /cygdrive/c/WINDOWS/system32/rpcrt4.dll Loaded symbols for /cygdrive/c/WINDOWS/system32/secur32.dll Program received signal SIGSEGV, Segmentation fault. 0x0022cc20 in ?? () (gdb) bt #0 0x0022cc20 in ?? () #1 0x004010a9 in _p__M0_S1_Q (J=200, A=@0x22cc20) at crashes.p:16 #2 0x004010c6 in _p__M0_S1_Q (J=100, A=@0x401050) at crashes.p:16 #3 0x004010e2 in _p__M0_main_program () at crashes.p:20 #4 0x0040115b in main (argc=1, argv=0x6927b0, envp=0x690090) at <implicit code>:22 I am pretty sure that this is a compiler bug, because this program used to run on MacPascal with no error. -- Regis Cridlig cridlig(a)gmail.com

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Re: FPC compiler bug: functional parameter invocation
by Prof A Olowofoyeku (The African Chief) 04 Apr '08

04 Apr '08

> On 3 Apr 2008 at 14:25, Régis Cridlig wrote: > > > What is the latest stable release of gpc? > > http://www.math.uni.wroc.pl/~hebisch/gpc/gpc-20070904.tar.bz2 You can get Cygwin binaries here: http://gnu-pascal.de/contrib/chief/win32/cygwin/ Best regards, The Chief -------- Prof. Abimbola A. Olowofoyeku (The African Chief) web: http://www.greatchief.plus.com/

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Re: FPC compiler bug: functional parameter invocation
by Prof A Olowofoyeku (The African Chief) 03 Apr '08

03 Apr '08

On 3 Apr 2008 at 12:14, Régis Cridlig wrote: [...] > > Here is the output of gpc -v > > > > $ gpc -v > > Reading specs from /usr/lib/gcc/i686-pc-cygwin/3.4.4/specs > > Configured with: > > /usr/build/package/orig/test.respin/gcc-3.4.4-3/configure --ver bose > > --prefix=/usr --exec-prefix=/usr --sysconfdir=/etc --libdir=/usr/lib > > --libe xecdir=/usr/lib --mandir=/usr/share/man --infodir=/usr/share/info > > --enable-langu ages=c,ada,c++,d,f77,pascal,java,objc --enable-nls > > --without-included-gettext -- enable-version-specific-runtime-libs > > --without-x --enable-libgcj --disable-java- awt --with-system-zlib > > --enable-interpreter --disable-libgcj-debug --enable-thre ads=posix > > --enable-java-gc=boehm --disable-win32-registry --enable-sjlj-exceptio ns > > --enable-hash-synchronization --enable-libstdcxx-debug Thread model: > > posix gpc version 20050331, based on gcc-3.4.4 (cygming special, gdc > > 0.12, using dmd 0 .125) That is a very old GPC release. I cannot reproduce the problem on gpc- 20060215 for example. Best regards, The Chief -------- Prof. Abimbola A. Olowofoyeku (The African Chief) web: http://www.greatchief.plus.com/

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