[cfe-dev] Memory consumption measurement results, for revision 100183

ihusar ihusar at fit.vutbr.cz
Fri Apr 2 06:24:31 PDT 2010

On Wed, 31 Mar 2010 18:33:08 +0200, Chris Lattner <clattner at apple.com>  

> On Mar 31, 2010, at 4:33 AM, ihusar wrote:
>>   so I did some memory consumption measurement and the results are as
>> follows:
>> source file size: 12MB
>> resulting .bc file with debug info has 250MB
>> clang: max. 4.8 GB
>> clang -fsyntax-only: max. ~120 MB
>> llvm-gcc: max. 4.1 GB
>> gcc 4.4.1: max 1.4 GB
>> opt -O3: max. 3.6 GB
>> source file size: 24MB
>> clang: max. 7.5 GB, stopped after 1 hour
>> gcc: after 11 seconds: gcc: Internal error: Segmentation fault (program
>> cc1), max. 1.4 GB
> This is interesting.  I infer that these memory usage numbers are for  
> "clang -O0 -g"?  If so, you might want to try a new build, last night  
> several memory and compile time improvements went in for debug info, and  
> more are coming.
> -Chris

   I made some tests for the latest revision 100183
and the memory consumption has gotten even higher compared to revision  

For the same 12MB file:

clang (no args): 5GB
clang -O0 -g0: 5GB
clang -O0 -g: 6.3GB, stopped after 33 minutes
opt --disable-output: 3.7 GB
opt -O3 --disable-output: 3.9 GB

Details can be found here:  
and http://lissom.aps-brno.cz/tmp/clang_rev99809.xls

I will probably solve this problem by splitting this large file into
smaller ones and by buying more memory, but I think it would be at
least interesting to see, what is the main reason that the memory  
is so much higher than in gcc.

Best regards

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