Gpc May 2006

gpc@gnu.de

9 participants
10 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

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

Bison-2.2
by Frank Heckenbach 07 Jun '06

07 Jun '06

Bison version 2.2 has been released. To make GPC work with it requires some minor changes. Patch attached, details in the ChangeLog entry. Bison 2.2 also has a new feature: : * %require "VERSION" : This specifies that the grammar file depends on features implemented : in Bison version VERSION or higher. Since we actively use some newer (2.0 and/or 2.1) features of Bison, we actually should use this check, to avoid users even trying with older Bisons which cannot work. OTOH, since the check is new in 2.2, we can't "%require 2.1", so by using this check we would needlessly (ATM) require Bison 2.2. What should we do? Perhaps wait until 2.2 is more widespread, then require it? Frank -- Frank Heckenbach, frank(a)g-n-u.de, http://fjf.gnu.de/, 7977168E GPC To-Do list, latest features, fixed bugs: http://www.gnu-pascal.de/todo.html GPC download signing key: ACB3 79B2 7EB2 B7A7 EFDE D101 CD02 4C9D 0FE0 E5E8

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Re: gpc installation using Xcode
by Adriaan van Os 31 May '06

31 May '06

Forwarding the private reply: Hi Adriaan, Thanks so much for your help - the program now works fine. I tried installing the compiler a long time ago, before the Xcode environment existed, and could never get anywhere with it, but it looks absolutely great now it works with Xcode - easy enough for me to use! Thanks again, Graham > Graham Carter wrote: > >> Examples/SillyBalls/Sources/MainProgram.pas >> gpc1: error: invalid option `dynamic-no-pic' > > I still have to update the GPC Xcode Kit, but you can apply the > following change to make it work. For IntelMac, please double-click > on the "Debug" Target. Then, in the Build Settings pane, change > > GPC_CODESTYLE = -mdynamic-no-pic > > to > > GPC_CODESTYLE = > > The -mdynamic-no-pic option is not (yet) supported for IntelMac. > Same procedure for the "Deploy" Target. > > The best place to ask Xcode specific questions is really the > MacPascal mailing list <http://www.pascal-central.com/maillist.html>. > > Regards, > > Adriaan van Os >

1 0

gpc installation using Xcode
by Graham Carter 31 May '06

31 May '06

Hi, I've just installed gpc, the associated Pascal interfaces and the Xcode software on my Intel Mac. I've configured Xcode in the way suggested and just tried to compile one of the sample programs. It compiles ok but falls over with this error: Building target “Debug” of project “SillyBalls” with configuration “Default” — (1 error) [lots of stuff deleted] 1.1/Examples/GUI Examples/SillyBalls/build/Debug/Objects/ -I . -I / Developer/Pascal/gpc345u2/lib/gcc/i386-apple-darwin8/3.4.5/units -I / Developer/Pascal/GPC Xcode Kit 1.1/Examples/GUI Examples/SillyBalls/ Sources/ --unit-path=/Developer/Pascal/GPC Xcode Kit 1.1/Examples/GUI Examples/SillyBalls/Sources/ -E -H /Developer/Pascal/GPC Xcode Kit 1.1/Examples/GUI Examples/SillyBalls/Sources/MainProgram.pas gpc1: error: invalid option `dynamic-no-pic' make: *** [compile_tool] Error 1 make: *** [compile_tool] Error 1 make: *** [compile_tool] Error 1 make: *** [compile_tool] Error 1 make: *** [compile_tool] Error 1 make: *** [compile_tool] Error 1 make: *** [compile_tool] Error 1 make: *** [compile_tool] Error 1 make: *** [compile_tool] Error 1 make: *** [compile_tool] Error 1 make: *** [compile_tool] Error 1 make: *** [compile_tool] Error 1 Build failed (1 error) Can anyone more knowledgeable than me (that would be most people!) suggest what I might need to do? Sorry to be a pain, I know the answer is probably obvious to everyone on this group but this is my first step into programming a Mac (or using a unix-like environment). Thanks in advance, Graham Carter

2 1

Xcode 2.3
by lanceboyle＠qwest.net 26 May '06

26 May '06

Should GPC folks upgrade to Xcode 2.3? What are the issues, if any? Jerry

2 3

modules and scope
by Ram Seshadri 18 May '06

18 May '06

Further to my previous e-mail I have a question relating to the use of modules and scope of variables declared in module being 'seen' by other modules. The thing is I have variables in one module that I want to be able to seen by other modules. I thought as long as I export the variables from the module it should be fine but it seems not to work all that well as on compiling I get undefined reference errors. I am a newbie to pascal so don't fully understand the inner workings so help would be appreciated.

2 1

.var files and include files
by Ram Seshadri 16 May '06

16 May '06

Does the latest version of the GNU compiler support the use of include files to declare procedures and functions. When i put them in include files I get compiler errors of multiple declarations. Help would be much appreciated. Ram

2 1

OS X 10.3 missing symbol ___powidf2 ?
by Glenn Howes 09 May '06

09 May '06

As you may recall, I have a large C++ application which calls a smallish library written in Pascal. I have compiled and linked that library as a universal binary which is intended to run under Mac OS X 10.3 and up on PowerPC, and Mac OS X 10.4 and up under i386. I had been running the application on Mac OS X 10.4 and up only, but have been going through the trouble of extending support to 10.3. But there is a symbol, apparently referenced from my Pascal library, which is missing. ___powidf2. I think this might be a math function of the form: float = pow(float, int); but am not sure. I've linked in libgpc, libgcc, and the darwin-fpsave libraries. Does anyone know how I should go about getting this to link? Googling and searching on this mailing list have not gotten be anywhere. --glenn

3 2

Range checking problem
by Adriaan van Os 05 May '06

05 May '06

The following was initially discovered by Gale Paeper. [g5:~/gpc/testgpc/adriaan] adriaan% cat rangecheck1.p program rangecheck1; var i: 1..5; begin i:= 5; {$local R-} i:= i+1; {$endlocal} i:= 4; i:= i+2; writeln( 'i = ', i); end. [g5:~/gpc/testgpc/adriaan] adriaan% gpc41 rangecheck1.p --range-checking [g5:~/gpc/testgpc/adriaan] adriaan% ./a.out i = 6 [g5:~/gpc/testgpc/adriaan] adriaan% cat rangecheck2.p {$R+} program rangecheck2; var i: 1..5; begin i:= 5; {$local R-} i:= i+1; {$endlocal} i:= 4; i:= i+2; writeln( 'i = ', i); end. [g5:~/gpc/testgpc/adriaan] adriaan% gpc41 rangecheck2.p --range-checking [g5:~/gpc/testgpc/adriaan] adriaan% ./a.out ./a.out: value out of range (error #300 at 2487) [g5:~/gpc/testgpc/adriaan] adriaan% cat rangecheck3.p {$R+} program rangecheck3; var i: 1..5; begin i:= 5; {$local R-} i:= i+1; {$endlocal} writeln( 'i = ', i); end. [g5:~/gpc/testgpc/adriaan] adriaan% gpc41 rangecheck3.p --range-checking [g5:~/gpc/testgpc/adriaan] adriaan% ./a.out i = 6 [g5:~/gpc/testgpc/adriaan] adriaan% cat rangecheck4.p {$R+} program rangecheck4; var i: 1..5; begin i:= 4; i:= i+2; writeln( 'i = ', i); end. [g5:~/gpc/testgpc/adriaan] adriaan% gpc41 rangecheck4.p --range-checking [g5:~/gpc/testgpc/adriaan] adriaan% ./a.out ./a.out: value out of range (error #300 at 2477) [g5:~/gpc/testgpc/adriaan] adriaan% gpc41 -v Using built-in specs. Configured with: ../gcc-4.1.0/configure --enable-languages=c,pascal --enable-threads=posix --target=powerpc-apple-darwin8 --host=powerpc-apple-darwin8 --build=powerpc-apple-darwin8 --prefix=/Developer/Pascal/gpc410d1 Thread model: posix gpc version 20060325, based on gcc-4.1.0 In other words, {$local R-} disables range-checking for the rest of the file when using --range-checking as a command-line option, not when using {$R+}. I can hardly imagine this is intended behaviour. Regards, Adriaan van Os

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Gpc May 2006