Re: [DynInst_API:] getLoopHead interface in BPatch_basicBlockLoop class

[Xiaozhu Meng <xmeng@xxxxxxxxxxx>]

It is more complicated than that. For a natural loop, it only has one
entry, which is also called the head because the entry dominates all
blocks of the loop. However, for an irreducible loop, it can have
multiple entries and it is possible that none of the entries dominates
the other blocks in the loop.

Thanks

--Xiaozhu

On Tue, Jul 28, 2015 at 10:58 AM, Jim Galarowicz <jeg@xxxxxxxxxxxxx> wrote:
> Hi Xiaozhu,
>
> Is the first entry in the vector e the loop head?
>
>
>                 BPatch_Vector<BPatch_basicBlock*> entries;
>                 loop->getLoopEntries(entries);
>                 BPatch_basicBlock* head = entries[0];
>
>                 if (head == NULL)
>                 {
>                     continue;
>                 }
>
>                 LoopInfo info(Address(head->getStartAddress()) -
> module_base);
>
>                 BPatch_Vector<BPatch_basicBlock*> blocks;
>                 loop->getLoopBasicBlocks(blocks);
>
>                 for (unsigned int i = 0; i < blocks.size(); ++i)
>                 {
>                     BPatch_basicBlock* block = blocks[i];
>
>
> Or is it more complicated than that?
>
> Thanks,
> Jim G
>
>
> Thanks,
> Jim G
> On 07/28/2015 10:37 AM, Xiaozhu Meng wrote:
>>
>> Hi Jim,
>>
>> The old getLoopHead() method has been replaced by the following new
>> interface to appropriately represent irreducible loops:
>>
>> int
>> BPatch_basicBlockLoop::getLoopEntries(BPatch_Vector<BPatch_basicBlock*> &e);
>>
>> The new interface returns the number of entry blocks of this loop and
>> the entries blocks are returned as the output parameter.
>>
>> On Tue, Jul 28, 2015 at 8:42 AM, Jim Galarowicz <jeg@xxxxxxxxxxxxx> wrote:
>>>
>>> Hi all,
>>>
>>> I've downloaded the git source version of dyninst and built it on NASA's
>>> pfe
>>> machine and my laptop in an attempt to run it on Intel MIC binaries.  The
>>> 8.2.1 asserts in switches related to the architecture type.
>>>
>>> However, I ran into a compile error with our loop code:
>>>
>>> [ 16%] Building CXX object
>>>
>>> libopenss-framework/CMakeFiles/openss-framework-symtabapi.dir/DyninstSymbols.cxx.o
>>> cd /u/jgalarow/OpenSpeedShop/build_mic_offline_fe/libopenss-framework &&
>>> /nasa/pkgsrc/2014Q3/gcc49/bin/g++   -DHAVE_DYNINST -DHAVE_STDINT_H=1
>>> -DHAVE_SYS_STAT_H=1 -DOPENSS_USE_SYMTABAPI=1
>>>
>>> -DOpenSpeedShop_LIBRARY_FILE_DIR=\"/nobackupp8/jgalarow/maia/pfe_ossoffline/lib64\"
>>> -DPACKAGE=1 -DPACKAGE_VERSION=1 -DVERSION=\"2.1\" -D_GNU_SOURCE
>>> -Dopenss_framework_symtabapi_EXPORTS -g -fPIC
>>> -I/u/jgalarow/OpenSpeedShop/libopenss-framework
>>> -I/u/jgalarow/OpenSpeedShop/build_mic_offline_fe/libopenss-framework
>>>
>>> -I/u/jgalarow/OpenSpeedShop/build_mic_offline_fe/libopenss-framework/offline
>>> -I/nasa/boost/1.50.0/include
>>> -I/nobackup/jgalarow/dyninst-9.0.0/include/dyninst
>>> -I/nobackup/jgalarow/dyninst-9.0.0/include
>>> -I/u/jgalarow/krellroot_v2.1u8/include
>>>
>>> -I/u/jgalarow/OpenSpeedShop/build_mic_offline_fe/libopenss-framework/../libopenss-framework
>>> -o CMakeFiles/openss-framework-symtabapi.dir/DyninstSymbols.cxx.o -c
>>> /u/jgalarow/OpenSpeedShop/libopenss-framework/DyninstSymbols.cxx
>>> /u/jgalarow/OpenSpeedShop/libopenss-framework/DyninstSymbols.cxx: In
>>> function 'std::vector<LoopInfo> getLoopsAt(const
>>> OpenSpeedShop::Framework::Address&, BPatch_image&)':
>>> /u/jgalarow/OpenSpeedShop/libopenss-framework/DyninstSymbols.cxx:140:49:
>>> error: 'class BPatch_basicBlockLoop' has no member named 'getLoopHead'
>>>                   BPatch_basicBlock* head = loop->getLoopHead();
>>>                                                   ^
>>> make[2]: ***
>>>
>>> [libopenss-framework/CMakeFiles/openss-framework-symtabapi.dir/DyninstSymbols.cxx.o]
>>> Error 1
>>> make[2]: Leaving directory
>>> `/home4/jgalarow/OpenSpeedShop/build_mic_offline_fe'
>>> make[1]: ***
>>> [libopenss-framework/CMakeFiles/openss-framework-symtabapi.dir/all] Error
>>> 2
>>> make[1]: Leaving directory
>>> `/home4/jgalarow/OpenSpeedShop/build_mic_offline_fe'
>>>
>>> I found this in my emails about dyninst:
>>>
>>> Hi,
>>>
>>> We are planing to improve our current loop detection algorithm to be able
>>> to
>>> handle irreducible loops. Such loops can have multiple entry blocks. For
>>> this matter, the original interface to get the loop head needs to be
>>> changed
>>> to return a vector of heads of a loop.
>>>
>>> The involved interface is:
>>>
>>> BPatch_basicBlock*  BPatch_basicBlockLoop::getLoopHead();
>>>
>>> We plan to change it to:
>>>
>>> bool BPatch_basicBlockLoop::getLoopHead(std::vector<BPatch_basicBlock*>&
>>> entries);
>>>
>>> Let us know if you are using the interface and if the interface change
>>> will
>>> cause significant inconvenience to you.
>>>
>>> Thanks
>>>
>>> --Xiaozhu
>>>
>>>
>>> However, I can't find any examples of the new getLoopHead code in the
>>> latest
>>> Dyninst source.   Can someone point me to it?
>>>
>>>
>>> pfe21-101>pwd
>>> /nobackupp8/jgalarow/OpenSpeedShop_ROOT/BUILD/pfe20/dyninst-9.0.0
>>>
>>> pfe21-94>grep basicBlockLoop::getLoopHead *
>>> pfe21-95>!!/*
>>> grep basicBlockLoop::getLoopHead */*
>>> pfe21-96>!!/*
>>> grep basicBlockLoop::getLoopHead */*/*
>>> pfe21-97>!!/*
>>> grep basicBlockLoop::getLoopHead */*/*/*
>>> pfe21-98>!!/*
>>> grep basicBlockLoop::getLoopHead */*/*/*/*
>>> pfe21-99>!!/*
>>> grep basicBlockLoop::getLoopHead */*/*/*/*/*
>>> pfe21-100>!!/*
>>> grep basicBlockLoop::getLoopHead */*/*/*/*/*/*
>>> pfe21-101>pwd
>>> /nobackupp8/jgalarow/OpenSpeedShop_ROOT/BUILD/pfe20/dyninst-9.0.0
>>>
>>> pfe21-104>grep getLoopHead *
>>> pfe21-105>!!/*
>>> grep getLoopHead */*
>>> pfe21-106>!!/*
>>> grep getLoopHead */*/*
>>> !!/*
>>>
>>> LOOKS LIKE THE OLD INTERFACE:
>>>
>>> dyninstAPI/src/hybridOverwrites.C://
>>> (*lIter)->getLoopHead()->getStartAddress(),
>>> dyninstAPI/src/hybridOverwrites.C://
>>> writeLoop->getLoopHead()->getStartAddress(),
>>> pfe21-107>!!/*
>>> grep getLoopHead */*/*/*
>>> pfe21-108>!!/*
>>> grep getLoopHead */*/*/*/*
>>> pfe21-109>!!/*
>>> grep getLoopHead */*/*/*/*/*
>>> pfe21-110>
>>>
>>>
>>> I need to change this to work with the new API:
>>> cat -n /u/jgalarow/OpenSpeedShop/libopenss-framework/DyninstSymbols.cxx
>>> ...
>>> ...
>>>
>>>    122                BPatch_Vector<BPatch_basicBlockLoop*> loops;
>>>     123                cfg->getLoops(loops);
>>>     124
>>>     125                for (unsigned int l = 0; l < loops.size(); ++l)
>>>     126                {
>>>     127                    BPatch_basicBlockLoop* loop = loops[l];
>>>     128
>>>     129                    if ((loop == NULL) ||
>>> !loop->containsAddressInclusive(
>>>     130                            (module_base + address).getValue()
>>>     131                            ))
>>>     132                    {
>>>     133                        continue;
>>>     134                    }
>>>     135
>>>     136                    // A loop containing this address has been
>>> found!
>>> Rejoice!
>>>     137                    // And, of course, obtain the loop's head
>>> address
>>> and basic
>>>     138                    // block address ranges...
>>>     139
>>>     140                    BPatch_basicBlock* head = loop->getLoopHead();
>>>     141
>>>     142                    if (head == NULL)
>>>     143                    {
>>>     144                        continue;
>>>     145                    }
>>>     146
>>>     147                    LoopInfo info(Address(head->getStartAddress())
>>> -
>>> module_base);
>>>     148
>>>     149                    BPatch_Vector<BPatch_basicBlock*> blocks;
>>>     150                    loop->getLoopBasicBlocks(blocks);
>>>     151
>>>     152                    for (unsigned int i = 0; i < blocks.size();
>>> ++i)
>>>     153                    {
>>> ...
>>> ...
>>>
>>>
>>> Thanks,
>>> Jim G
>>>
>>>
>>> On 09/23/2014 04:57 PM, Xiaozhu Meng wrote:
>>>
>>> Hi,
>>>
>>> We are planing to improve our current loop detection algorithm to be able
>>> to
>>> handle irreducible loops. Such loops can have multiple entry blocks. For
>>> this matter, the original interface to get the loop head needs to be
>>> changed
>>> to return a vector of heads of a loop.
>>>
>>> The involved interface is:
>>>
>>> BPatch_basicBlock*  BPatch_basicBlockLoop::getLoopHead();
>>>
>>> We plan to change it to:
>>>
>>> bool BPatch_basicBlockLoop::getLoopHead(std::vector<BPatch_basicBlock*>&
>>> entries);
>>>
>>> Let us know if you are using the interface and if the interface change
>>> will
>>> cause significant inconvenience to you.
>>>
>>> Thanks
>>>
>>> --Xiaozhu
>>>
>>>
>>> _______________________________________________
>>> Dyninst-api mailing list
>>> Dyninst-api@xxxxxxxxxxx
>>> https://lists.cs.wisc.edu/mailman/listinfo/dyninst-api
>>>
>>>
>