[cfe-dev] Introduction and a few questions

[Michael Price]

Hi List,

I've been developing with C++ code for the past 5 years and was introduced
to the idea behind clang/llvm late last year.  I've been following C++0x
developments since early 2008 however, and I am quite excited about the
(hopefully) forthcoming standard.  I decided recently to begin making
contributions to open-source C++ compilers to advance the implementation
level of the new standard so that it could be more widely adopted.  Seeing
how GCC is doing pretty good without any help (and most of the "easy")
topics are taken, I figured I'd help out some with clang.  I understand that
C++0x will not be a priority until the previous standards are implemented,
but it can't hurt to have a head start on C++0x implementation, right?  With
that out of the way, here are some questions I have:


I've built llvm/clang on Windows 7 x64 with Visual C++ 2010 Express (using
cmake to create a VS solution file).  The build succeeded with no errors.  I
have not run the test suite yet, but would like to do that soon as I have
some code changes that I'd like to verify with the tests before I submit a
patch.  Does anyone have any guidance on running the tests in the
environment I've described?


After building, I made a simple program (no #includes, simple main()
returning 0).  When I compiled it with the command 'clang.exe
clangtest.cpp', clang gave the following error:
clang: error: unable to execute command: program not executable
clang: error: assembler (via gcc) command failed due to signal 1 (use -v to
see invocation)

But, if I compile it with 'clang.exe clangtest.cpp -fsyntax-only', the
compilation succeeds.  Any ideas what is screwed up with my environment?


Also, if I #include any standard library headers, clang will choke, since
the VC++10 headers are implemented with some C++0x support (and some other
weird errors occur).  If anyone is interested in helping me with this, I'll
post the errors.  Otherwise, some direction on how to get either GCC library
or libc++ compiling and working on my environment would be extremely
helpful.


For my first contribution, I've decided to work on type deduction via the
'auto' type keyword (as opposed to the 'auto' storage-specifier :) ).  After
looking through the code, I've found the first "half" of an implementation,
in that the type declaration was already present.  I have some code
implemented which will modify the type of the declared variable (similar to
how unsized-arrays are done) based on the type of the initializer.  I still
need to review the latest standard proposal so that I can verify I've
covered all the cases (I doubt I have), or at least know what tests to
create so that it can be completed at a later date.  I browsed through the
list archive and noticed that Doug was working on an initialization rewrite,
but I don't see the results of that anywhere in the revision that I checked
out.  I want to make sure I don't step on any toes in there.  After I run
the tests, I'll build a patch and send it to the list for comments.


The next thing that I'm considering implementing is the new function
declaration syntax (auto func (param1, param2) -> rettype;), as I see it as
a building block towards implemented lambdas.  I'd also consider finishing
off any work on rvalue-references and move-constructors instead, as those
are extremely valuable and important pieces of the new standard library (see
unique_ptr).


Hopefully I'll be able to help out just a little and get some degree of
C++0x support in place before the C++0x goes through the entire process to
become the next standard.
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