Re: Spirit-X3 | Boost 1.59 | Compilation never finishes for a recursive grammar

On 04/21/2017 01:44 AM, Arun Muralidharan wrote:
> Hello Folks,
> I have posted the question in SO as well (
> http://stackoverflow.com/questions/43526708/optimizing-the-grammar ), but I
> believe I have better chance of getting an answer to my query here.
>
> <Reposting the question here>
>
> I am working on creating an xpath2.0 parser as per the RFC. It's basically a
> subproject of another project that I am working on.
>
> After some initial success, I did the mistake of writing a bunch of grammar
> rules and AST instead of compiling and testing it at every point. After that
> I basically had a novel of template error messages to read (my fault
> actually).
>
> I have then then tried to work my way up by trying to compile and test bits
> and pieces of the grammar rules individually and now I am stuck with the
> compilation process never ending.
>
> I am attaching two files along with this post:
> 1. All the code in a single cpp file.
> 2. Broken up the code in multiple files as suggested before in the mailing
> list. (as per calc9 example)
>
> Compiler - clang 3.8 on Mac (i7 processor 8 GB RAM)
> template-depth - 1024
> Boost Version - 1.59
>
> rec_ex_orig.cc
> <http://boost.2283326.n4.nabble.com/file/n4693813/rec_ex_orig.cc>
>
> rec_ex.tar <http://boost.2283326.n4.nabble.com/file/n4693813/rec_ex.tar>
>
I suspect the problem is here:

https://github.com/cppljevans/spirit/blob/get_rhs/include/boost/spirit/home/x3/nonterminal/detail/rule.hpp#L215

When this code was compiled without -DBOOST_SPIRIT_GET_RHS_CRTP=1
it took several minutes, consuming 100% of CPU1, and steadily
increased memory consumption.  However, with
-DBOOST_SPIRIT_GET_RHS_CRTP=1, it compile in a flash, as
shown by the attached.

HTH.

-regards,
Larry

------------------------------------------------------------------------------
Check out the vibrant tech community on one of the world's most
engaging tech sites, Slashdot.org! http://sdm.link/slashdot

_______________________________________________
Spirit-general mailing list
[email protected]
https://lists.sourceforge.net/lists/listinfo/spirit-general

-*- mode: compilation; default-directory: "~/prog_dev/boost/releases/ro/boost_1_63_0/sandbox/pull_requests/context_debug_fix.fork/spirit/workbench/x3/rec_ex_orig/" -*-
Compilation started at Fri Apr 21 12:24:34

make compile
/home/evansl/dwnlds/llvm/3.9/prebuilt/clang+llvm-3.9.0-x86_64-linux-gnu-ubuntu-16.04/bin/clang++ -c -O0 -stdlib=libc++  -std=c++1z -ftemplate-backtrace-limit=0 -fdiagnostics-show-template-tree -fno-elide-type -fmacro-backtrace-limit=0     -c -std=c++14 -ftemplate-depth=1024 -DBOOST_SPIRIT_GET_RHS_CRTP=1 -I/home/evansl/prog_dev/boost/releases/ro/boost_1_63_0/sandbox/pull_requests/context_debug_fix.fork/spirit/include -I/home/evansl/prog_dev/boost/releases/ro/boost_1_63_0 rec_ex_orig.cpp
In file included from rec_ex_orig.cpp:10:
In file included from /home/evansl/prog_dev/boost/releases/ro/boost_1_63_0/sandbox/pull_requests/context_debug_fix.fork/spirit/include/boost/spirit/home/x3.hpp:17:
In file included from /home/evansl/prog_dev/boost/releases/ro/boost_1_63_0/sandbox/pull_requests/context_debug_fix.fork/spirit/include/boost/spirit/home/x3/nonterminal.hpp:10:
/home/evansl/prog_dev/boost/releases/ro/boost_1_63_0/sandbox/pull_requests/context_debug_fix.fork/spirit/include/boost/spirit/home/x3/nonterminal/rule.hpp:23:11: warning: 
      not(BOOST_SPIRIT_ATTR_XFORM_IN_RULE) [-W#pragma-messages]
  #pragma message "not(BOOST_SPIRIT_ATTR_XFORM_IN_RULE)"
          ^
/home/evansl/prog_dev/boost/releases/ro/boost_1_63_0/sandbox/pull_requests/context_debug_fix.fork/spirit/include/boost/spirit/home/x3/nonterminal/rule.hpp:26:11: warning: 
      yes(BOOST_SPIRIT_GET_RHS_CRTP) [-W#pragma-messages]
  #pragma message "yes(BOOST_SPIRIT_GET_RHS_CRTP)"
          ^
2 warnings generated.

Compilation finished at Fri Apr 21 12:24:39