January 2006 - Gpc

Inefficiency of `mod'
by Emil Jerabek 26 Oct '10

26 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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Building gpc-20051104 on i686-apple-darwin8
by Adriaan van Os 01 Mar '06

01 Mar '06

> [Darwin:gcc/p/test] adriaan% gpc -v > Reading specs from > /Developer/Pascal/gpc344x1/lib/gcc/i686-apple-darwin8/3.4.4/specs > Configured with: ../gcc-3.4.4/configure --enable-languages=c,pascal > --enable-threads=posix --target=i686-apple-darwin8 > --host=i686-apple-darwin8 --build=i686-apple-darwin8 > --prefix=/Developer/Pascal/gpc344x1 > Thread model: posix > gpc version 20051104, based on gcc-3.4.4 > > (more about the testsuite in the next message) Because of <http://gcc.gnu.org/bugzilla/show_bug.cgi?id=22099> I ran the testsuite with --no-pic, so I had to tell the darwin linker to shut up complaining about that. [Darwin:gcc/p/test] adriaan% make EXTRA_PFLAGS="--no-pic -Wl,-read_only_relocs,suppress" rm -f *.dat *.o *.s *.i *.gpi *.gpd *.gpc core a.out stderr.out *.exe testmake.tmp dummy.c dummy.pas dummy.out diff_cr*.tmp fixcr fixcr.exe rm -f todo/a.out todo/*.exe todo/*.o todo/*.s todo/*.i todo/*.gpi todo/*.gpd todo/core GP= PC="gpc" PFLAGS=" --autobuild -g -O3 -W -Wall -Wno-unused --no-pic -Wl,-read_only_relocs,suppress " PFLAGS_NO_PATHS="-g -O3 -W -Wall -Wno-unused --no-pic -Wl,-read_only_relocs,suppress " SRCDIR="." TEST_MAKE_FLAG=test-make-flag "./test_run" "*.pas" | tee test_log | "./test_sum" -d Test Run By adriaan on 2005-11-14 00:37:07 Native configuration is i686-apple-darwin8 (Darwin.local) === gpc tests === Running target any Running testsuite ... UNSUPPORTED: agettext2test.pas UNSUPPORTED: agettexttest.pas UNSUPPORTED: aregextest.pas ^[[FAIL: backtracerr.pas ^R FAIL: bo4-19.pas FAIL: bprealtest.pas FAIL: emptyrec.pas FAIL: fay.pas UNSUPPORTED: fjf165a.pas FAIL: fjf35.pas FAIL: fjf464c.pas FAIL: fjf464e.pas FAIL: fjf908.pas FAIL: fproc.pas UNSUPPORTED: gmptest.pas FAIL: gpcu_c_u.pas FAIL: knuth1.pas FAIL: nicola4d.pas FAIL: nlgpp.pas FAIL: nlgpp2.pas FAIL: robert1a.pas FAIL: robert1b.pas FAIL: systemtest.pas FAIL: t6334-2.pas FAIL: t6p6p3p4.pas FAIL: waldek1.pas === gpc Summary === # of tests 4965 # of expected passes 4939 # of unexpected failures 21 # of unsupported tests 5 gpc version 20051104, based on gcc-3.4.4 Innocent ------- * systemtest failure is caused by a Max OS X bug * bo4-19.pas fails because of the linker option passed to the testsuite gpc: -read_only_relocs: linker input file unused because linking not done gpc: suppress: linker input file unused because linking not done, * emptyrec.pas, same * gpcu_c_u.pas, same * waldek1.pas, same Serious ------ * bprealtest.pas, segmentation fault Exception: EXC_BAD_ACCESS (0x0001) Codes: KERN_PROTECTION_FAILURE (0x0002) at 0x00000041 Thread 0 Crashed: 0 dyld 0x8fe03d1b dyld::bindLazySymbol(mach_header const*, unsigned long*) + 119 1 dyld 0x8fe135cf stub_binding_helper_interface + 61 2 a.out 0x00001000 0x1000 + 0 3 a.out 0x000020c6 _p__M6_System_S63_Realtobpreal + 102 (system.pas:425) 4 a.out 0x0000305e _p__M0_main_program + 142 (bprealtest.pas:25) 5 a.out 0x000033ba main + 58 (<implicit code>:36) 6 a.out 0x00001cfe _start + 228 (crt.c:272) 7 a.out 0x00001c19 start + 41 ? maybe floating point exception * fay.pas, bus error Exception: EXC_BAD_ACCESS (0x0001) Codes: KERN_PROTECTION_FAILURE (0x0002) at 0xbffff6d0 Thread 0 Crashed: 0 <<00000000>> 0xbffff6d0 0 + -1073744176 1 a.out 0x00002da8 Q.5 + 168 (fay.pas:92) 2 a.out 0x00002dbd _p__M0_S6_Outer + 13 (fay.pas:90) 3 a.out 0x00002e2a main + 58 (<implicit code>:134) 4 a.out 0x0000211e _start + 228 (crt.c:272) 5 a.out 0x00002039 start + 41 ? procedural parameter and local procedure problems (? trampolines ?) the following test failures look the same: * backtraceerr.pas * fjf35.pas * fjf464c.pas * fjf464e.pas * fproc.pas, same * knuth1.pas, same * nicola4d.pas, same * nlgpp.pas * nlgpp2.pas * t6334-2.pas * t6p6p3p4.pas * fjf908.pas failed 89 1.000000000000000e+00 2.500000000000000e-01 * robert1a.pas x ** y = NaN trunc( x ** y) = 0 * robert1b.pas 10.0 ** y = NaN trunc( 10.0 ** y) = 0 Anything I can do to investigate this further and report it to gcc bugzilla ? Regards, Adriaan van Os

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Ada calling Pascal (not working)
by lanceboyle＠qwest.net 03 Feb '06

03 Feb '06

(This post is related to two earlier posts by me, "Linking Ada to Pascal" and 'Where is documentation for "new argument to _p_initialize (@)" PCStrings.') I have not been able to solve the problem when calling _p_initialize from Ada. I still get the Ada compiler telling me, "too many arguments in call." I suspect that I might be passing the wrong _kinds_ of arguments but not the wrong number. Here are the three relevant files: <file adacallspascal.adb> with Ada.Text_IO; use Ada.Text_IO; with Ada.Command_Line; use Ada.Command_Line; with Ada.Integer_Text_IO; use Ada.Integer_Text_IO; procedure adacallspascal is procedure mypascalprocedure; pragma Import(Convention => C, Entity => mypascalprocedure); procedure init_pascal_main_program; pragma Import(Convention => C, Entity => init_pascal_main_program, External_Name => "_p__M0_init"); procedure p_initialize; pragma Import(Convention => C, Entity => p_initialize, External_Name => "_p_initialize"); procedure p_finalize; pragma Import(Convention => C, Entity => p_finalize, External_Name => "_p_finalize"); Argument_Count_Plus_1 : integer := Argument_Count + 1; Command_Name_String : string := Command_Name; C_Command_Name_String : aliased string := Command_Name_String & ASCII.NUL; begin Put_Line ("Hello from adacallspascal."); Put(Argument_Count_Plus_1); New_Line; Put_Line(Command_Name_String); -- Initialize the Pascal RTS. p_initialize (Argument_Count_Plus_1, C_Command_Name_String'access, null, 0); -- Line 29 init_pascal_main_program; mypascalprocedure; p_finalize; Put_Line ("Goodbye from adacallspascal."); end adacallspascal; <file mypascalprogram.pas> program mypascalprogram(input, output); {$gpc-main=dummy} procedure mypascalprocedure; attribute( name = 'mypascalprocedure'); begin writeln('Hello from mypascalprocedure.'); end; begin {When exported to Ada, this part should not be called.} writeln('In mypascalprogram; error if calling from Ada.'); end. <The commands> gpc -c mypascalprogram.pas gnatmake adacallspascal.adb -gnatf -largs mypascalprogram.o / Developer/Pascal/gpc344d2/lib/gcc/powerpc-apple-darwin8/3.4.4/libgpc.a <Output from attempting to compile> gcc -c -gnatf adacallspascal.adb adacallspascal.adb:29:05: too many arguments in call gnatmake: "adacallspascal.adb" compilation error Jerry

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Re: Getting an error while compiling GPC-20050331 on HP-UX11i v2
by prasad svr 02 Feb '06

02 Feb '06

Hi, I tried with gpc-20051116 on HP-UX11i v2 (Itanium),i am geeting an error like ocal/ia64-hp-hpux11.23/include -isystem /usr/local/ia64-hp-hpux11.23/sys-include' ' | sed -e 's,$-[BI]$$[^/][^:]$,\1../../\2,g;s,^$[^/][^:]*/$,../../\1,'`" PC="`echo ./xgpc -B./' ' | sed -e 's,$-[BI]$$[^/][^:]$,\1../../\2,g;s,^$[^/][^:]*/$,../../\1,'`" GCC_VERSION="3.4.3" SHELL="/bin/sh" CFLAGS="-g -O2" PFLAGS="" AR_FLAGS="rc" RTSFLAGS="" DESTDIR="../.." AR="ar" RANLIB="ranlib" RANLIB_TEST="" all make[2]: Entering directory `/gcc/gpcbuild/gcc/p/rts' echo '{ rts-config.inc. Generated automatically from rts-config.h. }' > rts-config.inc sed -e 's,/\*,{,g;s,\*/,},g;s,^[ \t]*#$.*$,{$\1},' rts-config.h >> rts-config.inc ../.././xgpc -B../.././ -I. -W -Wall -Wmissing-prototypes -Wmissing-declarations -g -O2 --unit-path=/gcc/gcc-3.4.3/gcc/p/rts --automake --print-needed-options "/gcc/gcc-3.4.3/gcc/p/rts/endian.pas" 2> "needed-options" || true if grep '^[^-]' "needed-options" > /dev/null; then echo "needed-options: `cat "needed-options"`" >&2; rm -f "needed-options"; false; else true; fi needed-options: /gcc/gcc-3.4.3/gcc/p/rts/endian.pas:37: error: module/unit interface `Error' could not be imported make[2]: *** [needed-options] Error 1 make[2]: Leaving directory `/gcc/gpcbuild/gcc/p/rts' make[1]: *** [pascal.rts] Error 2 make[1]: Leaving directory `/gcc/gpcbuild/gcc' make: *** [all-gcc] Error 2 can any one help on this. Regards Prasad > ----- Original Message ----- > From: "Waldek Hebisch" <hebisch(a)math.uni.wroc.pl> > To: gpc(a)gnu.de > Subject: Re: Getting an error while compiling GPC-20050331 on HP-UX11i v2 (Itanium > Date: Fri, 27 Jan 2006 15:53:27 +0100 (CET) > > > prasad svr wrote: > > I am trying to compile GPC-20050331 on HP-UX11i v2 (Itanium 64 > > bit) Using gcc-3.4.3.While compiling Iam getting an error like > > bellow. > > > > > > gcc ?c -DUSE_LIBUNWIND_EXCEPTIONS -g -O2 -DIN_GCC -W -Wall > > -Wwrite-string -Wstrict-prototypes -Wmissing -Prototypes > > -pedantic -Wno-long-long -DHAVE_CONFIG_H > > -DGENERATOT_FILE -I. ?I. > > > > -I/gcc/gcc-3.4.3/gcc -I/gcc/gcc-3.4.3/gcc/. > > ?I/gcc/gcc-3.4.3/gcc/../include -I ../intl > > /gcc/gcc-3.4.3/gcc/gcov-iov.c -o gcov-iov.o > > > > In file included from /gcc/gcc-3.4.3/gcc/gcov-iov.c: 27: > > > > /gcc/gcc-3.4.3/gcc/version.c: 8 error: Conflicting type for `version string' > > /gcc/gcc-3.4.3/gcc/version.h: 3 error: previous declaration of > > `version string' was here > > /gcc/gcc-3.4.3/gcc/version.c: 8 error: conflicting types for `version string' > > /gcc/gcc-3.4.3/gcc/version.h: 3 error: previous declaration of > > `version string' was here > > > > First suspect is incorrectly patched backend: gpc contains a patch which > modifies both `version.c' and `version.h'. If only one of them is patched > you will get errors as above. > > gpc-20050331 is likely to have problems on IA-64, but the above is _not_ > one of expected problems. To avoid other problems I would suggerst > to use gpc-20051116 version from: > > http://www.math.uni.wroc.pl/~hebisch/gpc/gpc-20051116.tar.bz2 > > or search the mailing list archives for patches. > > -- > Waldek Hebisch > hebisch(a)math.uni.wroc.pl > -- _______________________________________________ Search for businesses by name, location, or phone number. -Lycos Yellow Pages http://r.lycos.com/r/yp_emailfooter/http://yellowpages.lycos.com/default.as…

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Buffer Overrun Prevention in GPC
by Mirsad Todorovac 30 Jan '06

30 Jan '06

Hi, all! I have recently studied several forms of viruses and security holes in software. Many if not 90% of recent exploits depend on holes introduced through buffer overruns, such as this C example: printbuffer() { char buffer[100]; gets (buffer); /* oops!*/ fp = fopen("LPT1:", "w"); fputs (buffer, fp); } Is Pascal and namely GNU Pascal safer re: buffer overruns? How much does runtime range checking help and to what extent can we depend on it? Is it acceptable to write setuid root programs in GPC and what are the cautions? Thanks for answers. Mirsad "Tvrdim da bi se napetost izmedju znanosti i vjere trebala rijesiti njihovom sintezom, a ne odbacivanjem ili podvojenoscu." Pierre Teilhard de Chardin (1881-1955)

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Internal compiler error with readstring
by Peter Schorn 28 Jan '06

28 Jan '06

The following program crashes the compiler (gpc345u2 on Mac OS 10.4.4): program rs; { compile with gpc rs.pas } var a: integer; begin readstring(a); { internal compiler error: Bus error } end. Best regards, Peter

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Getting an error while compiling GPC-20050331 on HP-UX11i v2 (Itanium 64 bit) using gcc-3.4.3.
by prasad svr 27 Jan '06

27 Jan '06

Hi, I am trying to compile GPC-20050331 on HP-UX11i v2 (Itanium 64 bit) Using gcc-3.4.3.While compiling Iam getting an error like bellow. gcc c -DUSE_LIBUNWIND_EXCEPTIONS -g -O2 -DIN_GCC -W -Wall -Wwrite-string -Wstrict-prototypes -Wmissing -Prototypes -pedantic -Wno-long-long -DHAVE_CONFIG_H -DGENERATOT_FILE -I. I. -I/gcc/gcc-3.4.3/gcc -I/gcc/gcc-3.4.3/gcc/. I/gcc/gcc-3.4.3/gcc/../include -I ../intl /gcc/gcc-3.4.3/gcc/gcov-iov.c -o gcov-iov.o In file included from /gcc/gcc-3.4.3/gcc/gcov-iov.c: 27: /gcc/gcc-3.4.3/gcc/version.c: 8 error: Conflicting type for `version string' /gcc/gcc-3.4.3/gcc/version.h: 3 error: previous declaration of `version string' was here /gcc/gcc-3.4.3/gcc/version.c: 8 error: conflicting types for `version string' /gcc/gcc-3.4.3/gcc/version.h: 3 error: previous declaration of `version string' was here make[1]: *** [gcov-iov.o] Error 1 make[1]: Leaving directory `/gcc/gpcbuild/gcc' make: *** [all-gcc] Error 2 any one can help on this problem. Regards Prasad -- _______________________________________________ Search for businesses by name, location, or phone number. -Lycos Yellow Pages http://r.lycos.com/r/yp_emailfooter/http://yellowpages.lycos.com/default.as…

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MinGW -mwindows -mconsole
by Adriaan van Os 25 Jan '06

25 Jan '06

Has somebody worked with gpc on MinGW passing both -mwindows and -mconsole to create both a console box and GUI stuff ? Is a different thread needed for the GUI ? Regards, Adriaan van Os

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Question about -Widentifier-case
by Peter Schorn 24 Jan '06

24 Jan '06

I have a question on the meaning of the identifier-case warning in gpc (gpc345u2 on Mac OS 10.4.4). Compiling the program below I get three warnings but I'd expect none since in all three cases the two referenced variables are different. Is my expectation wrong? Best regards, Peter { 1} program cap; { 2} { compile with gpc -o cap -Widentifier-case cap.pas } { 3} { 4} procedure p(A: integer); { 5} { 6} procedure q(a: integer); { cap.pas:6: warning: capitalisation of identifier `a' doesn't match } { 8} { cap.pas:4: warning: previous capitalisation `A' } { 9} begin {10} a := 1; {11} end; {12} {13} begin { p } {14} A := 0; { cap.pas:14: warning: capitalisation of identifier `A' doesn't match } {16} { cap.pas:6: warning: previous capitalisation `a' } {17} end; {18} {19} procedure r(a: integer); { cap.pas:19: warning: capitalisation of identifier `a' doesn't match } {21} { cap.pas:14: warning: previous capitalisation `A' } {22} begin {23} a := 1; {24} end; {25} {26} begin {27} end.

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Creating Universal static library called from XCode 2.2.1 Carbon Application
by Glenn Howes 23 Jan '06

23 Jan '06

I have a legacy static library written in Pascal which I need to call from a C++ application targeting both PowerPC and x86 processors on the Mac OS X platform ( a so-called universal binary). After compiling and linking everything together, I'm having trouble calling the Pascal runtime libraries: i.e. I crash. Software used: glenn% gpc -v Reading specs from /Developer/Pascal/gpc345u2/lib/gcc/powerpc-apple- darwin8/3.4.5/specs Configured with: ../gcc-3.4.5/configure --enable-languages=pascal,c -- enable-threads=posix --target=powerpc-apple-darwin8 --host=powerpc- apple-darwin8 --build=powerpc-apple-darwin8 --prefix=/Developer/ Pascal/gpc345u2 Thread model: posix gpc version 20051116, based on gcc-3.4.5 gpc-i386 -vReading specs from /Developer/Pascal/gpc345u2/lib/gcc/i386- apple-darwin8/3.4.5/specs Configured with: ../gcc-3.4.5/configure --enable-languages=pascal,c -- enable-threads=posix --target=i386-apple-darwin8 --host=powerpc-apple- darwin8 --build=powerpc-apple-darwin8 --prefix=/Developer/Pascal/ gpc345u2 --with-sysroot=/Developer/SDKs/MacOSX10.4u.sdk/ --with- arch=pentium-m --with-tune=prescott Thread model: posix gpc version 20051116, based on gcc-3.4.5 Mac OS X 10.4.4 XCode 2.2.1 Source: 34 files of legacy Pascal which I've gone through and fixed all of the compiler errorss and most of the warnings. Steps I've taken. 1) Compiled and packaged using gpc, libtool, and lipo: gpc -c --automake -Wl,-framework,Carbon -funit-path=/Developer/Pascal/ GPCPInterfaces/ MySrc.p libtool -static *.o -o MyLibPPC.a rm *.gpi rm *.o gpc-i386 -c --automake -Wl,-framework,Carbon -funit-path=/Developer/ Pascal/GPCPInterfaces/ MySrc.p libtool -static *.o -o MyLibx86.a lipo *.a -create -output MyLib.a 2) Made a universal version of the gpc.a library lipo /Developer/Pascal/gpc345u2/lib/gcc/i386-apple-darwin8/3.4.5/ libgpc.a /Developer/Pascal/gpc345u2/lib/gcc/powerpc-apple- darwin8/3.4.5/libgpc.a -create -output gpc.a 3) Added both libraries to my XCode 2.2.1 C++ application 4) Compile and Links without running, crashes as soon as it tries to call WriteLn, if I remove the WriteLn, it crashes later in a call to the file routine Assign, which might be the first runtime library call. I declare the entry in C++ as: extern "C" short MyEntry(const char *path); In Pascal, I declare it as const MaxPointerChars = 20000; Type PAPointerChar=^APointerChar; APointerChar = Packed Array [0..MaxPointerChars] of Char; Int16 = Integer attribute ( size = 16); ... function MyEntry(DllPathC:PAPointerChar):Int16; attribute (name = 'MyEntry'); ... function MyEntry(aCString:PAPointerChar):Int16; var DLLPath:String2048; pathLength:Int32; i:Int32; begin pathLength := StrLen(aCString); if pathLength > 2048 then pathLength := 2048; DLLPath := ''; for i := 1 to pathLength do begin DLLPath := DLLPath + aCString^[i-1]; end; WriteLn(DLLPath); { crashes here} ... gdb gives me the following console output: Running… Program received signal: "EXC_BAD_ACCESS". Unable to disassemble _p_Write_Init. 5) I've written a little test application in Pascal to debug the libraries code (when it is not packaged as a library but compiled directly into the application) and the code works perfectly well in that environment. The debugging was done with XCode 2.1 as I believe there is a problem with gpc and XCode 2.2. So how do I fix this?

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