Patrick Simmons
2010-Mar-19 10:37 UTC
[LLVMdev] Getting the DSNode from a Pool Descriptor?
Thanks for all your help so far. My problem is that what I have are the pool descriptors, which I by traversing the uses of poolinit and accessing the first argument of each call. I need to find the DSNode (in the original function) to which this pool descriptor corresponds. The rub is that this pool descriptor of course does not exist except in the clone. If I call getFuncInfo(), I get a NULL pointer. getFuncInfoOrClone() returns the original function's FuncInfo structure, but this function's DSNode <-> PoolDescriptor mapping will not have my pool descriptor in it because my pool descriptor only existed in the clone. I'm fine with the DSNode being the original function's DSNode -- in fact, I need that -- but I'm really at a loss as to how to get out of this catch-22. --Patrick On 03/19/10 04:10, Harmen van der Spek wrote:> Hi Patrick, > > That's right. DSNodes are coupled to the original function. For function clones, you first need > to get the original function, and then use the DSNode from that function. FuncInfo > contains the information if a function is a clone and what the original function is. > > If you want to find the corresponding DSNode for some instruction, you must call > > PA::FuncInfo::MapValueToOriginal( value ) > > Then you can get the DSNode from the DSGraph: > > llvm::DSNodeHandle handle = _dsg->getNodeForValue(origVal); > DSNode *node = handle.getNode(); > > origVal is obtained by calling MapValueToOriginal on a cloned Value. > > All those mappings are quite confusing. I've been thinking about splitting Pool allocation in two phases, > one in which the clones are generated (which should be internal functions) and then, instead of maintaining all these mappings, just > rerun Top-Down DSA on that result. In that case, it would be much easier to find DSNodes. Anyway, this was just > a thought, I've not really tried anything like that. > > Harmen > > > On Mar 19, 2010, at 9:14 AM, Patrick Alexander Simmons wrote: > > >> Harmen, your suggestion of inverting the mapping almost worked (and Andrew was correct that the function I need is the same as the one in which poolinit appears). Unfortunately, it appears that this mapping only considers the original function and not any of its clones. Since the pool descriptor in question may very well only exist in a clone, I can't use this. Is there another way? >> >> Thanks, >> --Patrick >> >> Harmen van der Spek wrote: >> >>> You might want to have a look at PoolAllocate.h. >>> >>> Per function, a PA::FuncInfo structure keeps track of all DSNodes that should be pool allocated. ArgNodes contains pool arguments, NodesToPA >>> contains nodes that are locally pool allocated and thus initialized using poolinit. >>> >>> PoolDescriptors contains a mapping from DSNodes to pool descriptors, and >>> you could easily invert this mapping. >>> >>> Finding a corresponding DSNode which is complete is not uniquely determined. For example, if a function F uses a pool, but its DSNode >>> is incomplete, it might be called from two different function G and H, >>> which both have a complete DSNode that maps to the DSNode in F. >>> >>> You can assume that if a function is cloned, so that its DSNodes >>> are pool allocated, those DSNodes originate from a complete DSNode >>> somewhere higher in the call chain. >>> >>> Per function, a pool-allocated version can be generated. After that, >>> function calls are rewritten to call the pool allocated version. This is done in TransformFunctionBody.cpp. by calling TransformBody from PoolAllocate.cpp. >>> >>> >>> >>> Harmen >>> >>> >>> >>> Patrick Alexander Simmons wrote: >>> >>> >>>> I figure (hopefully correctly) that I can iterate over all pool descriptors in a program by iterating over all users of poolinit and looking at the first argument. However, once I have a pool descriptor, I need to get its corresponding DSNode in the function in which it is complete (or in the global graph if it is a global). How do I do this? >>>> >>>> Thanks, >>>> --Patrick >>>> >>>> >>> _______________________________________________ >>> LLVM Developers mailing list >>> LLVMdev at cs.uiuc.edu http://llvm.cs.uiuc.edu >>> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev >>> >>> > > _______________________________________________ > LLVM Developers mailing list > LLVMdev at cs.uiuc.edu http://llvm.cs.uiuc.edu > http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev >-- If I'm not here, I've gone out to find myself. If I get back before I return, please keep me here.
Andrew Lenharth
2010-Mar-19 12:42 UTC
[LLVMdev] Getting the DSNode from a Pool Descriptor?
On Fri, Mar 19, 2010 at 5:37 AM, Patrick Simmons <simmon12 at illinois.edu> wrote:> Thanks for all your help so far. > > My problem is that what I have are the pool descriptors, which I by > traversing the uses of poolinit and accessing the first argument of each > call. I need to find the DSNode (in the original function) to which > this pool descriptor corresponds. The rub is that this pool descriptor > of course does not exist except in the clone. > > If I call getFuncInfo(), I get a NULL pointer. getFuncInfoOrClone() > returns the original function's FuncInfo structure, but this function's > DSNode <-> PoolDescriptor mapping will not have my pool descriptor in it > because my pool descriptor only existed in the clone. I'm fine with the > DSNode being the original function's DSNode -- in fact, I need that -- > but I'm really at a loss as to how to get out of this catch-22.PoolDescriptors do not have DSNodes in any meaningful sense, so if you are trying to lookup the PD pointer you will have problems. PA adds the pointer to the DSGraph, but it doesn't corrospond to it's logical contents at all. FuncInfo contains a map which should contain all DSNode->PD mappings, which you can invert. Andrew> > --Patrick > > On 03/19/10 04:10, Harmen van der Spek wrote: >> Hi Patrick, >> >> That's right. DSNodes are coupled to the original function. For function clones, you first need >> to get the original function, and then use the DSNode from that function. FuncInfo >> contains the information if a function is a clone and what the original function is. >> >> If you want to find the corresponding DSNode for some instruction, you must call >> >> PA::FuncInfo::MapValueToOriginal( value ) >> >> Then you can get the DSNode from the DSGraph: >> >> llvm::DSNodeHandle handle = _dsg->getNodeForValue(origVal); >> DSNode *node = handle.getNode(); >> >> origVal is obtained by calling MapValueToOriginal on a cloned Value. >> >> All those mappings are quite confusing. I've been thinking about splitting Pool allocation in two phases, >> one in which the clones are generated (which should be internal functions) and then, instead of maintaining all these mappings, just >> rerun Top-Down DSA on that result. In that case, it would be much easier to find DSNodes. Anyway, this was just >> a thought, I've not really tried anything like that. >> >> Harmen >> >> >> On Mar 19, 2010, at 9:14 AM, Patrick Alexander Simmons wrote: >> >> >>> Harmen, your suggestion of inverting the mapping almost worked (and Andrew was correct that the function I need is the same as the one in which poolinit appears). Unfortunately, it appears that this mapping only considers the original function and not any of its clones. Since the pool descriptor in question may very well only exist in a clone, I can't use this. Is there another way? >>> >>> Thanks, >>> --Patrick >>> >>> Harmen van der Spek wrote: >>> >>>> You might want to have a look at PoolAllocate.h. >>>> >>>> Per function, a PA::FuncInfo structure keeps track of all DSNodes that should be pool allocated. ArgNodes contains pool arguments, NodesToPA >>>> contains nodes that are locally pool allocated and thus initialized using poolinit. >>>> >>>> PoolDescriptors contains a mapping from DSNodes to pool descriptors, and >>>> you could easily invert this mapping. >>>> >>>> Finding a corresponding DSNode which is complete is not uniquely determined. For example, if a function F uses a pool, but its DSNode >>>> is incomplete, it might be called from two different function G and H, >>>> which both have a complete DSNode that maps to the DSNode in F. >>>> >>>> You can assume that if a function is cloned, so that its DSNodes >>>> are pool allocated, those DSNodes originate from a complete DSNode >>>> somewhere higher in the call chain. >>>> >>>> Per function, a pool-allocated version can be generated. After that, >>>> function calls are rewritten to call the pool allocated version. This is done in TransformFunctionBody.cpp. by calling TransformBody from PoolAllocate.cpp. >>>> >>>> >>>> >>>> Harmen >>>> >>>> >>>> >>>> Patrick Alexander Simmons wrote: >>>> >>>> >>>>> I figure (hopefully correctly) that I can iterate over all pool descriptors in a program by iterating over all users of poolinit and looking at the first argument. However, once I have a pool descriptor, I need to get its corresponding DSNode in the function in which it is complete (or in the global graph if it is a global). How do I do this? >>>>> >>>>> Thanks, >>>>> --Patrick >>>>> >>>>> >>>> _______________________________________________ >>>> LLVM Developers mailing list >>>> LLVMdev at cs.uiuc.edu http://llvm.cs.uiuc.edu >>>> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev >>>> >>>> >> >> _______________________________________________ >> LLVM Developers mailing list >> LLVMdev at cs.uiuc.edu http://llvm.cs.uiuc.edu >> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev >> > > > -- > If I'm not here, I've gone out to find myself. If I get back before I return, please keep me here. > > _______________________________________________ > LLVM Developers mailing list > LLVMdev at cs.uiuc.edu http://llvm.cs.uiuc.edu > http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev >
Patrick Simmons
2010-Mar-19 14:56 UTC
[LLVMdev] Getting the DSNode from a Pool Descriptor?
On 03/19/10 08:56, John Criswell wrote:> Patrick Simmons wrote: >> Thanks for all your help so far. >> >> My problem is that what I have are the pool descriptors, which I by >> traversing the uses of poolinit and accessing the first argument of >> each call. I need to find the DSNode (in the original function) to >> which this pool descriptor corresponds. The rub is that this pool >> descriptor of course does not exist except in the clone. > > One way to do this might be to search for a use of the pool within the > function (such as a poolalloc() or a function call that passes the > pool). You can then find a pointer that belongs to the pool, map that > pointer from the clone back to the original function, and then look up > its DSNode. > > However, before you do that, can you tell us why you need this > functionality? Since things are getting complicated, it may be > worthwhile to first understand if your approach of mapping Pools to > the DSNodes from which they were created is the correct approach for > what you are doing. If, for example, you need to know whether a pool > is a type-homogeneous, then an easier method would be to modify > poolinit() to pass an argument containing DSNode information (such as > a flag indicating type-homogeneity). > > -- John T.I've thought of trying to do that, but that solution is really too ugly to live. I need this because NSPASS (my project) runs after DSA but before pool allocation and generates a list of DSNodes with a special property. Then, TPPA (still my project) needs to iterate over every pool, which it does by iterating over the uses of poolinit, and figure out whether that pool needs to be annotated in a special way based on whether the DSNode from whence it came had the special property. To do this, it needs to convert the pool descriptor it gets by taking the first argument of poolinit back into the DSNode it used to be and then check the information from NSPASS to see whether it needs a special annotation. Is there a better way to do this? Thanks, --Patrick -- If I'm not here, I've gone out to find myself. If I get back before I return, please keep me here.
Patrick Simmons wrote:> Thanks for all your help so far. > > My problem is that what I have are the pool descriptors, which I by > traversing the uses of poolinit and accessing the first argument of each > call. I need to find the DSNode (in the original function) to which > this pool descriptor corresponds. The rub is that this pool descriptor > of course does not exist except in the clone. >One way to do this might be to search for a use of the pool within the function (such as a poolalloc() or a function call that passes the pool). You can then find a pointer that belongs to the pool, map that pointer from the clone back to the original function, and then look up its DSNode. However, before you do that, can you tell us why you need this functionality? Since things are getting complicated, it may be worthwhile to first understand if your approach of mapping Pools to the DSNodes from which they were created is the correct approach for what you are doing. If, for example, you need to know whether a pool is a type-homogeneous, then an easier method would be to modify poolinit() to pass an argument containing DSNode information (such as a flag indicating type-homogeneity). -- John T.> If I call getFuncInfo(), I get a NULL pointer. getFuncInfoOrClone() > returns the original function's FuncInfo structure, but this function's > DSNode <-> PoolDescriptor mapping will not have my pool descriptor in it > because my pool descriptor only existed in the clone. I'm fine with the > DSNode being the original function's DSNode -- in fact, I need that -- > but I'm really at a loss as to how to get out of this catch-22. > > --Patrick > > On 03/19/10 04:10, Harmen van der Spek wrote: > >> Hi Patrick, >> >> That's right. DSNodes are coupled to the original function. For function clones, you first need >> to get the original function, and then use the DSNode from that function. FuncInfo >> contains the information if a function is a clone and what the original function is. >> >> If you want to find the corresponding DSNode for some instruction, you must call >> >> PA::FuncInfo::MapValueToOriginal( value ) >> >> Then you can get the DSNode from the DSGraph: >> >> llvm::DSNodeHandle handle = _dsg->getNodeForValue(origVal); >> DSNode *node = handle.getNode(); >> >> origVal is obtained by calling MapValueToOriginal on a cloned Value. >> >> All those mappings are quite confusing. I've been thinking about splitting Pool allocation in two phases, >> one in which the clones are generated (which should be internal functions) and then, instead of maintaining all these mappings, just >> rerun Top-Down DSA on that result. In that case, it would be much easier to find DSNodes. Anyway, this was just >> a thought, I've not really tried anything like that. >> >> Harmen >> >> >> On Mar 19, 2010, at 9:14 AM, Patrick Alexander Simmons wrote: >> >> >> >>> Harmen, your suggestion of inverting the mapping almost worked (and Andrew was correct that the function I need is the same as the one in which poolinit appears). Unfortunately, it appears that this mapping only considers the original function and not any of its clones. Since the pool descriptor in question may very well only exist in a clone, I can't use this. Is there another way? >>> >>> Thanks, >>> --Patrick >>> >>> Harmen van der Spek wrote: >>> >>> >>>> You might want to have a look at PoolAllocate.h. >>>> >>>> Per function, a PA::FuncInfo structure keeps track of all DSNodes that should be pool allocated. ArgNodes contains pool arguments, NodesToPA >>>> contains nodes that are locally pool allocated and thus initialized using poolinit. >>>> >>>> PoolDescriptors contains a mapping from DSNodes to pool descriptors, and >>>> you could easily invert this mapping. >>>> >>>> Finding a corresponding DSNode which is complete is not uniquely determined. For example, if a function F uses a pool, but its DSNode >>>> is incomplete, it might be called from two different function G and H, >>>> which both have a complete DSNode that maps to the DSNode in F. >>>> >>>> You can assume that if a function is cloned, so that its DSNodes >>>> are pool allocated, those DSNodes originate from a complete DSNode >>>> somewhere higher in the call chain. >>>> >>>> Per function, a pool-allocated version can be generated. After that, >>>> function calls are rewritten to call the pool allocated version. This is done in TransformFunctionBody.cpp. by calling TransformBody from PoolAllocate.cpp. >>>> >>>> >>>> >>>> Harmen >>>> >>>> >>>> >>>> Patrick Alexander Simmons wrote: >>>> >>>> >>>> >>>>> I figure (hopefully correctly) that I can iterate over all pool descriptors in a program by iterating over all users of poolinit and looking at the first argument. However, once I have a pool descriptor, I need to get its corresponding DSNode in the function in which it is complete (or in the global graph if it is a global). How do I do this? >>>>> >>>>> Thanks, >>>>> --Patrick >>>>> >>>>> >>>>> >>>> _______________________________________________ >>>> LLVM Developers mailing list >>>> LLVMdev at cs.uiuc.edu http://llvm.cs.uiuc.edu >>>> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev >>>> >>>> >>>> >> _______________________________________________ >> LLVM Developers mailing list >> LLVMdev at cs.uiuc.edu http://llvm.cs.uiuc.edu >> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev >> >> > > >
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