[LLVMdev] Running Pool Allocated programs

[Chris Lattner]

On Sat, 2 Apr 2005, Ricardo wrote:
> After applying the PA to it, the output is something like this:
...

> My question is: why is this malloc necessary?
> ltmp_2_5 = malloc(4u);

> Shouldn't be the result a program with this malloc replaced by poolalloc?
> Should I include a special flag to achieve this?

Ah, sorry, my memory was wrong.  The default is to perform the 
"SelectivePA" optimization.  Since pool allocation detected that there is 
no point in putting a single allocation into a pool, it left it a malloc. 
If you really want it to be a in a pool, pass 
-poolalloc-heuristic=AllNodes to opt.

Sorry for the confusion!

-Chris

> I am using this line:
> opt -load ~/llvm/install/lib/libpoolalloc.so -poolalloc
> and also with -pooloptimize
>
> Thanks in advance
>
>
>
>
> --- Chris Lattner <sabre at nondot.org> wrote:
>
>> On Sat, 2 Apr 2005, Ricardo wrote:
>>> Hello,
>>> I am trying to run a program optimized with the Pool Allocation, but I am receiving this
>> error:
>>>
>>> ====================
>>>
>>> *** 4 DYNAMIC POOLS INITIALIZED ***
>>>
>>> *** 4 DYNAMIC POOLS ALLOCATED FROM ***
>>>
>>> MaxHeapSize = 0.062500KB  HeapSizeAtExit = 0.062500KB   NOTE: only valid if using
>>> Heuristic=AllPools and no bumpptr/realloc!
>>> ====================
>>
>> This output is what happens when you link with the debug version of the
>> runtime library.  If you rebuild the FL2Allocator with 'make
>> ENABLE_OPTIMIZED=1' and link with the result, you shouldn't get this.
>>
>>> I have tried to link the program with the Analysis and with Datastructure libs:
>>> llvm-gcc -o test test.opt.bc -lpoolalloc -lpoolalloc_rt -lLLVMDataStructure -lLLVMAnalysis
>>> But I am still receiving the error.
>>
>> You should only need -lpoolalloc_rt.
>>
>> For the record, I usually do (effectively) this to test the pool
>> allocator:
>>
>> llvm-gcc *.c -o program         # compile&link whole prog with LLVM
>> opt -load ... -poolalloc program.bc ... -o program.pa.bc
>> llc program.pa.bc -march=c -o program.pa.cbe.c
>> gcc -fno-strict-aliasing -O2 program.pa.cbe.c -o program.pa
>> -L~/llvm/projects/llvm-poolalloc/Release/lib/ -lpoolalloc_rt
>>
>> Alternatively, if you want a quick test, you can do the first two steps,
>> then:
>>
>>    lli -load ~/llvm/projects/llvm-poolalloc/Release/lib/libpoolalloc_rt.so program.pa.bc
>>
>> If you're on a target that supports the JIT.
>>
>>> Another question, I do not want to use the bump ptr optimization, and I suppose that the right
>>> heuristic for that is AllNodes? But if I want to use it, what is the right heuristic?
>>
>> The AllNodes heuristic is the only one that is substantially tested.  I
>> would recommend it, none of the others have any significant performance
>> benefit anyway.
>>
>> The bump pointer and other opts are a seperate option -pooloptimize, which
>> can be run after -poolalloc.  It does not work with -pointercompress
>> though.
>>
>>> Also, if I want to use the Pointer Compression, I suppose that I have to
>>> use the -pointercompress switch with opt or what?
>>
>> Yes, if you use it, don't specify -poolalloc manually.
>>
>> -Chris
>>
>> --
>> http://nondot.org/sabre/
>> http://llvm.cs.uiuc.edu/
>>
>
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-Chris

-- 
http://nondot.org/sabre/
http://llvm.cs.uiuc.edu/