[LLVMdev] Status of blocks runtime in compiler-rt?

Shantonu Sen ssen at apple.com
Mon Sep 21 18:21:22 PDT 2009

Hi Jordan,

I've committed my changes to hook up the BlocksRuntime/ subdirectory  
of compiler-rt, using CMake.

The cmake build process is documented at <http://llvm.org/docs/CMake.html 

More specifically, to use this support on FreeBSD, for example, you  
would do:

1) Install cmake (<http://www.cmake.org/>), add it to your PATH
2) Check out the source code for llvm and clang
3) Build it with cmake, using:
$ mkdir build
$ cd build
$ env CC="cc -march=i686" CXX="c++ -march=i686" cmake - 
$ make
$ make install

4) Check out the source code for compiler-rt
5) Build it, optionally with clang, although this isn't strictly  
required. You can use the system gcc too, like in step 3.
$ mkdir build
$ cd build
$ env CC="clang" CXX="c++ -march=i686" cmake -DCMAKE_INSTALL_PREFIX= 
$ make
$ make install

Simple programs seem to work at that point for me:
$ cat foo.c
#include <stdio.h>
#include <stdlib.h>
#include <Block.h>

int main(int argc, char *argv[]) {

   int x = 123;

   void (^printXAndY)(int) = ^(int y) {
     printf("%d %d\n", x, y);
   void (^copyPrintXAndY)(int) = Block_copy(printXAndY);

   copyPrintXAndY(456); // prints: 123 456

   return 0;

$ clang -I$PREFIX/include -fblocks -c foo.c
$ clang -L$PREFIX/lib -Wl,-rpath,$PREFIX/lib -o foo foo.o - 
$ ./foo
123 456

I've also tried similar steps on Ubuntu Linux, as well as with llvm- 
gcc-4.2, which also worked.

Shantonu Sen
ssen at apple.com

Sent from my Mac Pro

On Sep 16, 2009, at 8:00 AM, Shantonu Sen wrote:

> The Blocks language and implementation specifications are checked into
> clang/docs.
> More generally, on Mac OS X, the blocks runtime is linked into the C
> library ("libSystem"), and available to the entire OS. Clients that
> create blocks may implicitly get compiler-generated calls to some of
> the runtime functions, and the developer may also make explicit calls
> to, e.g., Block_copy().
> On other OSes, the library would need to be built and installed
> somewhere. There's also the question of whether it should be a shared
> library or static library. I can see both points, but think that a
> shared library is probably the right way for it.
> It should probably be generally portable (it doesn't appear to
> compiler correctly with llvm-gcc and clang on Linux), and install its
> headers (doesn't appear to).
> I can spend some time on this, since I have some familiarity with
> libdispatch (Apple's APIs that heavily use Blocks for developer
> convenience).
> Shantonu
> Sent from my MacBook
> On Sep 15, 2009, at 4:42 PM, Edward O'Callaghan wrote:
>> Good day,
>> I been working on the CMake build system (which is nice and portable)
>> + code clean ups over the whole Compiler-RT software suit.
>> I recently added Blocks to the CMake build system but there is some
>> ugly looking warnings I need to fix up in the Blocks code which I  
>> have
>> not had time to look into yet.
>> N.B. The CMake build system is not complete yet due to my lack of
>> time, however I am still active, help really welcome !
>> My main goal is to have Compiler-RT as a highly portable runtime that
>> will build and run on AuroraUX, *BSD, Linux and OSX with lint clean
>> code and zero build warnings. Also, I plan to add SPARC support in  
>> the
>> near future if I get time. (As I work on AuroraUX almost full time
>> also.)
>> These are my personal goals working on Compiler-RT.
>> Could you please outline *exactly* what you would like to see happen
>> with Blocks,
>> I don't really know much about Blocks to be fair however I would be
>> interested to hear and at least it would be 'on record' here.
>> Cheers,
>> Edward O'Callaghan.
>> 2009/9/15 Jordan K. Hubbard <jkh at apple.com>:
>>> Hi folks,
>>> So, various folks are in the process of porting Grand Central
>>> Dispatch
>>> to FreeBSD (c.f. http://libdispatch.macosforge.org and http://lists.macosforge.org/pipermail/libdispatch-dev
>>> for mailing list discussion on the topic) and are making good
>>> progress, but one of the issues they're running into is support for
>>> Blocks in FreeBSD.
>>> On the one hand, they could try and back-port the gcc changes from http://www.opensource.apple.com/source/gcc/gcc-5646
>>> and solve the problem that way or, on the other hand, they could
>>> just continue FreeBSD's inexorable march towards Clang and get the
>>> blocks support as part of compiler-rt.  The only problem seems to be
>>> that the build support for Blocks in compiler-rt isn't wired up yet,
>>> which came as something of a surprise to all involved given that
>>> people have been talking about Clang and Blocks since this summer.
>>> Is there a roadmap for this anywhere that we can read?  If this
>>> simply
>>> has not been done due to a lack of resources, the GCD porting folks
>>> could perhaps help move this along, assuming they had appropriate
>>> access to the bits.
>>> Thanks!
>>> - Jordan
>>> _______________________________________________
>>> LLVM Developers mailing list
>>> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
>>> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev
>> -- 
>> -- 
>> Edward O'Callaghan
>> http://www.auroraux.org/
>> eocallaghan at auroraux dot org
>> _______________________________________________
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