cfg representation
Hi, I've been looking at the cfg that gcc dumps to a file. I'm noticing that the code is transformed in the cfg. Especially the short circuited expressions and the ternary operator for C/C++. Is there a particular algorithm gcc uses to transform the original AST into the modified version in the CFG? Does anyone know where the code is that does this transformation so I can look for myself? Thanks, Bob Rossi
printing cfg
Hi,
I'm trying to print the cfg so that I can visualize it. I have a simple
file,
$ cat foo.c
int
foo (int param)
{
param++;
if (param)
param++;
return param;
}
I run the command,
$ gcc -fdump-tree-vcg-blocks -c foo.c
and then I run,
xvcg *.vcg
which displays a picture of the cfg. It appears for some reason, that
the expressions in the basic blocks just show things like,
modify_expr (4)
cond_expr (5)
Is there a way to make it show the actual expressions in the code
instead? Also, is there a native way to display this information using
dot instead?
Thanks,
Bob Rossi
Re: Looking for specific pages from Muchnick's book
On Thu, Mar 08, 2007 at 10:05:11AM +0100, Steven Bosscher wrote: Hi, I found this old patch (http://gcc.gnu.org/ml/gcc-patches/2003-06/msg01669.html) that refers to pages 202-214 of Muchnick's Advanced Compiler Design and Implementation book. That book still is not in my own compiler books collection because of its price. I used to have access to a copy in a university library, but that copy has been removed from the collection and, apparently, it's been disposed off :-( Could someone scan those pages and send them to me, please? Hi, With a little hard work, you can make google show you the pages. http://books.google.com/books?vid=ISBN1558603204id=Pq7pHwG1_OkCpg=PP1lpg=PP1ots=4VaZHsi8qTdq=Advanced+Compiler+Design+and+Implementationsig=w20IRwAK8s3z7gCUB1LSzmPqOf0#PRA1-PA202,M1 If you search for 'structural analysis', pages 202, 203, 204, 205, 210, 211, 212 and 214 come up. You only need to make it show you 5 more pages. Bob Rossi
compile time enforcement of exception specification
Hi, Will g++ ever add a compile time enforcement of the exception specification like the Java compiler does? I find the exception specification almost useless with out this functionality. Thanks, Bob Rossi
Re: compile time enforcement of exception specification
On Sun, Jan 14, 2007 at 12:16:32AM -0500, Andrew Pinski wrote: Hi, Will g++ ever add a compile time enforcement of the exception specification like the Java compiler does? I find the exception specification almost useless with out this functionality. The C++ standard ( 15.4/10) is very specific that the implemantion should not reject code just because of exception specification and calling other functions. Do you have a link to the standard some where? Will g++ not implement compile time enforcement until a standard says it's OK to do so? This feature is obviously an improvement over doing nothing. Wouldn't an option to g++ be only helpful here? Thanks, Bob Rossi
mingw build error
Hi, Every time I build a gcc for mingw, I get the same error as reported here, http://gcc.gnu.org/ml/gcc/2006-09/msg00044.html Basically, I have to edit the Makefile in gcc/Makefile like this, -ORIGINAL_LD_FOR_TARGET = ./C:/mingw/bin/../lib/gcc/mingw32/3.4.2/../../../../mingw32/bin/ld.exe +ORIGINAL_LD_FOR_TARGET = /C/mingw/bin/../lib/gcc/mingw32/3.4.2/../../../../mingw32/bin/ld This is still broken with the latest snapshot from 4.1. How would I go about fixing this? Is this a problem with the way I'm configuring gcc? Thanks, Bob Rossi
relocatable gdb
Hi, I've been responding to an old thread regarding building gcc in mingw so that it can be relocatable. I'm not sure if the discussion should be on gcc-patches, so I'm moving it here. This link has the script I'm running to automate the build, http://gcc.gnu.org/ml/gcc-patches/2006-12/msg01181.html This link has the output of the commands 'gcc -v -o main main.c' and 'g++ -v -o main main.cpp' which are both Hello World programs. The gcc executable can find stdio.h but the g++ exe can not find the iostream header. http://gcc.gnu.org/ml/gcc-patches/2006-12/msg01182.html I'm imagining the multiple messages ignoring nonexistent directory C:/msys/1.0/home/bobbybrasko/g++... have something to do with this. Thanks for any assistance I could get on this. Bob Rossi
distributing g++
Hi, I've compiled g++ for mingw with, ../gcc-4.1.1/configure --prefix=/home/bobbybrasko/g++/prefixdir --host=mingw32 \ --target=mingw32 --program-prefix= \ --program-suffix=-4.1 --with-gcc --with-gnu-ld --with-gnu-as --enable-threads --disable-nls \ --enable-languages=c,c++ --disable-win32-registry --disable-shared --without-x \ --enable-interpreter --enable-hash-synchronization --enable-libstdcxx-debug Since i've used a prefix, I'm assumming gcc wants to be installed where I told it to be. I'm wondering 2 things. What are the standard practices with installing multiple versions of gcc on a system. I renamed this gcc to be gcc-4.1. However, it looks like it will still overwrite some files when I do 'make install'. Is this true? How do people put multiple version on the same machine? Second, say I wanted to tar up a release of gcc that i've built for others to use. When the other user downloads and untars the file on there filesystem in an arbitrary point, I'm assumming it won't work because it's not in the --prefix=.. directory. Is it possible to get around this? I would like a user to be able to untar it anywhere, and have it work just fine. If this is possible, please advise. Thanks, Bob Rossi
Re: distributing g++
On Fri, Dec 15, 2006 at 12:35:23PM -0800, Brian Dessent wrote: Bob Rossi wrote: Since i've used a prefix, I'm assumming gcc wants to be installed where I told it to be. I'm wondering 2 things. It's not supposed to be that way. The toolchain is supposed to be relocatable for MinGW targets. I don't know if it currently is, but read the past threads on the topic first: http://gcc.gnu.org/ml/gcc/2006-04/threads.html#00227 http://gcc.gnu.org/ml/gcc/2006-04/threads.html#00441 Ranjit Mathew also has a web page somewhere describing what steps and/or patches are necessary to get a relocatable toolchain. But I think he does a crossed-native (canadian) build for speed reasons, so that may complicate the procedure. OK, I followed this tutorial I believe. http://rmathew.com/articles/gcj/bldgcj.html the section Building a Native Compiler. I ran this, #!/bin/sh tar -zxvf gcc-core-4.1.1.tar.gz tar -zxvf gcc-g++-4.1.1.tar.gz mkdir builddir cd builddir ../gcc-4.1.1/configure --prefix=/mingw --host=mingw32 \ --target=mingw32 --program-prefix= \ --program-suffix=-4.1 --with-gcc --with-gnu-ld --with-gnu-as --enable-threads --disable-nls \ --enable-languages=c,c++ --disable-win32-registry --disable-shared --without-x \ --enable-interpreter --enable-hash-synchronization --enable-libstdcxx-debug \ 21 | tee configure-out.txt make bootstrap 21 | tee make-out.txt make DESTDIR=/home/bobbybrasko/g++-4.1-relocatable install $ ls /home/bobbybrasko/g++-4.1-relocatable mingw $ ls /home/bobbybrasko/g++-4.1-relocatable/mingw bin include info lib libexec man share Am I doing the correct thing here? Pretend this isn't mingw even, would this be the correct way to do this for native linux? Now, How would I tar this up so that it could be relocatable? Thanks, Bob Rossi
Re: building gcc
On Sat, Oct 14, 2006 at 02:16:01PM +1000, Brendon Costa wrote: Bob Rossi wrote: Hi Ian, Basically, I want to use GCC with C,C++. I want to walk a tree that GCC creates for the translation units. I would like to know if for these two languages if I should use a language dependent tree, the generic tree or the gimple tree. In general, I would like to use the tree that most closely resembles the source language, and that is documented best. For starters, can you recommend which tree structure I should use in GCC? If so, would it be to much to ask to point me to the object in the source code that represents the tree after the tree has been populated? If I should be using gimple, I found this paper. ftp://gcc.gnu.org/pub/gcc/summit/2003/GENERIC%20and%20GIMPLE.pdf Is there any other good documentation on this? I cant help much as i have only been fumbling around in the GCC source for a short time now and still have no idea about a lot of stuff. However I did want to also look at the full tree for the C++ front end. I did this from the parser.c: cp_parser_translation_unit() function just after the call to: finish_translation_unit() and I was looking at the tree defined globally elsewhere in the variable: global_namespace Thanks Brendon, that was really helpful. I'm very new at this, and may have some seemingly rather odd questions. I see that global_namespace is of type 'union tree_node'. Is this the C++ language dependent AST? I found the documentation doc/c-tree.info. Is this the documentation representing the global_namespace tree? Is there any better documentation that you know of? Also, I noticed that converting it to html failed. Maybe this is a documentation error? Thanks again, Bob Rossi $ makeinfo --html ../../../gcc/gcc/doc/c-tree.texi ../../../gcc/gcc/doc/c-tree.texi:10: `Trees' has no Up field (perhaps incorrect sectioning?). makeinfo: Removing output file `/home/bob/rcs/svn/gcc/gcc/builddir/gcc/doc/c-tree/index.html' due to errors; use --force to preserve. $ makeinfo --version makeinfo (GNU texinfo) 4.8
Re: building gcc
On Thu, Oct 12, 2006 at 07:45:52AM -0700, Ian Lance Taylor wrote: Bob Rossi [EMAIL PROTECTED] writes: Hopefully I'll be able to debug gcc nicely after this is built. Two more questions that could save me a lot of time. Do you know where the abstract syntax tree is stored in GCC after a file is parsed? I'm not sure what kind of answer you are looking for. One place to look is in the cgraph code. Does GCC still create an AST for C/C++, or does it go directly to GIMPLE? gcc generates an AST, of sorts, for C++. For C it goes directly to GIMPLE (really GENERIC, but they are pretty similar). Hi Ian, Basically, I want to use GCC with C,C++. I want to walk a tree that GCC creates for the translation units. I would like to know if for these two languages if I should use a language dependent tree, the generic tree or the gimple tree. In general, I would like to use the tree that most closely resembles the source language, and that is documented best. For starters, can you recommend which tree structure I should use in GCC? If so, would it be to much to ask to point me to the object in the source code that represents the tree after the tree has been populated? If I should be using gimple, I found this paper. ftp://gcc.gnu.org/pub/gcc/summit/2003/GENERIC%20and%20GIMPLE.pdf Is there any other good documentation on this? Thanks, Bob Rossi
Re: building gcc
On Thu, Oct 12, 2006 at 09:48:13AM +0200, Paolo Bonzini wrote: In particular, I was just wondering how do compile GCC with debug. Not how to debug it. I tried CFLAGS=-g ./configure ..., but it still compiled with gcc -O2 -g. Anyways, if anyone knows a helpful configure trick that will help get me ready to debug gcc, please let me know. By default, GCC bootstraps itself, and after the first stage it always compiles itself with optimization enabled. So what you need is ./configure --enable-languages=c,c++ --disable-bootstrap make CFLAGS=-g (or equivalently, with CFLAGS=-g passed to configure). Thanks Paolo, Here's what I have so far. ../gcc/configure CFLAGS=-g --enable-languages=c,c++ --enable-checking --disable-bootstrap --prefix=$PWD/../prefixdir Hopefully I'll be able to debug gcc nicely after this is built. Two more questions that could save me a lot of time. Do you know where the abstract syntax tree is stored in GCC after a file is parsed? Does GCC still create an AST for C/C++, or does it go directly to GIMPLE? Thanks for the help, Bob Rossi
Re: building gcc
On Thu, Oct 12, 2006 at 06:56:58AM -0400, Bob Rossi wrote: On Thu, Oct 12, 2006 at 09:48:13AM +0200, Paolo Bonzini wrote: In particular, I was just wondering how do compile GCC with debug. Not how to debug it. I tried CFLAGS=-g ./configure ..., but it still compiled with gcc -O2 -g. Anyways, if anyone knows a helpful configure trick that will help get me ready to debug gcc, please let me know. By default, GCC bootstraps itself, and after the first stage it always compiles itself with optimization enabled. So what you need is ./configure --enable-languages=c,c++ --disable-bootstrap make CFLAGS=-g (or equivalently, with CFLAGS=-g passed to configure). Thanks Paolo, Here's what I have so far. ../gcc/configure CFLAGS=-g --enable-languages=c,c++ --enable-checking --disable-bootstrap --prefix=$PWD/../prefixdir Actually, the CFLAGS=-g caused a problem. OK, now, as I expected, I configure with ../gcc/configure --enable-languages=c,c++ --enable-checking --disable-bootstrap --prefix=$PWD/../prefixdir and the gcc that is put into prefixdir is compiled with -O2 and -g, which makes it hard to follow in the debugger. Anyone have a clue on how to compile gcc so only -g is used, and not -O2? Typically, I use the CFLAGS trick, but it doesn't seem to work for gcc. Thanks, and sorry for all the noise. Bob Rossi
Re: building gcc
On Thu, Oct 12, 2006 at 12:25:04PM -0400, Daniel Jacobowitz wrote: On Thu, Oct 12, 2006 at 12:22:57PM -0400, Bob Rossi wrote: and the gcc that is put into prefixdir is compiled with -O2 and -g, which makes it hard to follow in the debugger. Anyone have a clue on how to compile gcc so only -g is used, and not -O2? Typically, I use the CFLAGS trick, but it doesn't seem to work for gcc. Use CFLAGS=-g ../gcc-src/configure. The top level file is still autoconf 2.13. Thanks Daniel! It works now. Bob Rossi
building gcc
Hi, I'd like to build gcc with just the C/C++ front ends. Are there any configure options I could use to make only a minimum gcc build to get those 2 languages working? Also, I'd like to be able to debug gcc. Is there any special flags for this? Finally, once it's built, I'd like to manually traverse the AST. Any pointers on where this would be? Thanks, Bob Rossi
Re: building gcc
On Wed, Oct 11, 2006 at 02:39:39PM -0700, David Daney wrote: Bob Rossi wrote: Hi, I'd like to build gcc with just the C/C++ front ends. Are there any configure options I could use to make only a minimum gcc build to get those 2 languages working? Take a look at the Fine documentation that is available at http://gcc.gnu.org Yes, thanks. In particular looking at the installation documentation where it describes the --enable-languages=c,c++ configure option would be useful. Thank you, this is what I was looking for. The answers to your other questions can be found in the documents and WIKI at gcc.gnu.org. In particular, I was just wondering how do compile GCC with debug. Not how to debug it. I tried CFLAGS=-g ./configure ..., but it still compiled with gcc -O2 -g. Anyways, if anyone knows a helpful configure trick that will help get me ready to debug gcc, please let me know. Thanks, Bob Rossi
