[PATCH] Code coverage mapping generation that enables coverage using the instrumentation based profiling

Alex L arphaman at gmail.com
Mon Jul 21 10:09:09 PDT 2014


Updated patch with renamed coverage mapping variable and -fcoverage-mapping
option.




2014-07-18 17:40 GMT-07:00 Bob Wilson <bob.wilson at apple.com>:

>
> On Jul 18, 2014, at 5:36 PM, Alex L <arphaman at gmail.com> wrote:
>
>
>
>
> 2014-07-18 17:34 GMT-07:00 Bob Wilson <bob.wilson at apple.com>:
>
>>
>> On Jul 18, 2014, at 2:36 PM, Alex L <arphaman at gmail.com> wrote:
>>
>>
>>
>>
>> 2014-07-18 14:23 GMT-07:00 Argyrios Kyrtzidis <kyrtzidis at apple.com>:
>>
>>>  CodeGenABITypes::CodeGenABITypes(ASTContext &C,
>>>                                   llvm::Module &M,
>>> -                                 const llvm::DataLayout &TD)
>>> +                                 const llvm::DataLayout &TD,
>>> +                                 CoverageSourceInfo &CoverageInfo)
>>>
>>> Shouldn’t this be optional pointer ("CoverageSourceInfo *CoverageInfo =
>>> nullptr”) that will receive an object only when ‘ProfileInstrGenerate’
>>> option is enabled ?
>>>
>>
>> Yes, this is a good idea. I've updated the patch.
>>
>>
>> Two new comments:
>>
>> 1) Can you rename the variable used to hold the coverage mapping from
>> “__llvm_covmapping” to “__llvm_coverage_mapping”?
>>
>> 2) I think it would be good to put this under control of an
>> “experimental” command line option while we refine the details. We don’t
>> want to break anyone using -fprofile-instr-generate, and leaving it
>> disabled by default would also make it clear that this is still a work in
>> progress
>>
>
> What about '-fcoverage-mapping-generate'?
>
>
> Here I am asking for more verbose variable name (see above), but that
> seems unnecessarily long to me. How about shortening it to
> “-fcoverage-mapping”?
>
> You should also add a check to make sure it is only used with
> -fprofile-instr-generate.
>
>
>>
>>>
>>> On Jul 18, 2014, at 2:13 PM, Alex L <arphaman at gmail.com> wrote:
>>>
>>> This is the updated patch with the applied fixes, addition of
>>> CoverageSourceInfo and the usage of one section for all of the coverage
>>> mapping down.
>>> Alex
>>>
>>>
>>> 2014-07-18 13:43 GMT-07:00 Argyrios Kyrtzidis <kyrtzidis at apple.com>:
>>>
>>>> That sounds good to me.
>>>>
>>>> On Jul 18, 2014, at 1:38 PM, Alex L <arphaman at gmail.com> wrote:
>>>>
>>>> The 'CoverageSourceInfo' class that stores the skipped ranges is not a
>>>> good approach because when the llvm codegenerator is created the
>>>> preprocessing record doesn't actually have the skipped ranges as they
>>>> aren't reached by the lexer yet.
>>>> What about this: the 'CoverageSourceInfo' derives from PPCallbacks and
>>>> stores it's own source ranges instead of relying on the preprocessing
>>>> record. I think that this might be an even better approach as
>>>> lib/Frontend/CompilerInstance.cpp wouldn't have to be modified.
>>>> Alex
>>>>
>>>>
>>>> 2014-07-18 12:06 GMT-07:00 Alex L <arphaman at gmail.com>:
>>>>
>>>>>
>>>>>
>>>>>
>>>>> 2014-07-18 11:47 GMT-07:00 Argyrios Kyrtzidis <kyrtzidis at apple.com>:
>>>>>
>>>>>
>>>>>> On Jul 18, 2014, at 9:56 AM, Sean Silva <chisophugis at gmail.com>
>>>>>> wrote:
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> On Thu, Jul 17, 2014 at 2:14 PM, Bob Wilson <bob.wilson at apple.com>
>>>>>> wrote:
>>>>>>
>>>>>>>
>>>>>>> > On Jul 8, 2014, at 10:43 AM, Alex L <arphaman at gmail.com> wrote:
>>>>>>> >
>>>>>>> > Hi everyone,
>>>>>>> >
>>>>>>> > I've attached a patch with the initial implementation of the code
>>>>>>> coverage mapping generation that
>>>>>>> > enables code coverage analysis which uses the data obtained from
>>>>>>> the instrumentation based profiling.
>>>>>>> >
>>>>>>> > I've sent out the patches for the coverage mapping format library
>>>>>>> and the updated coverage tool in separate threads.
>>>>>>> >
>>>>>>> > Cheers,
>>>>>>> > Alex
>>>>>>> > <clangCoverageMapping.patch>
>>>>>>>
>>>>>>> This looks really nice! It is obviously blocked by getting the llvm
>>>>>>> changes in, but it is otherwise mostly ready to commit. I just have a few
>>>>>>> small comments.
>>>>>>>
>>>>>>> It is unfortunate that you have to propagate the Preprocessor
>>>>>>> through a bunch of code to make it available in CodeGen. I can’t think of
>>>>>>> any good alternative, though. It would be good to get someone more familiar
>>>>>>> with the overall structure of the front-end to review that part.
>>>>>>>
>>>>>>
>>>>>> Agreed. That seems sort of funky. Does the code use anything other
>>>>>> than the PreprocessingRecord? Could we just pass that down instead of the
>>>>>> full Preprocessor?
>>>>>>
>>>>>>
>>>>>> Looks like only SkippedRanges are used from the PreprocessingRecord.
>>>>>> Could we have something like ‘CoverageSourceInfo’ class containing the
>>>>>> SkippedRanges (and anything else useful) and thread this through to CodeGen
>>>>>> ?
>>>>>>
>>>>>>
>>>>> Yes, only the SkippedRanges are used. A separate class like
>>>>> 'CoverageSourceInfo' sounds like a good idea, I will pass it instead of the
>>>>> preprocesor to CodeGen.
>>>>>
>>>>>>
>>>>>> Notwithstanding my suggestion, someone with better knowledge of the
>>>>>> layering here should sign off before this gets committed.
>>>>>>
>>>>>> -- Sean Silva
>>>>>>
>>>>>>
>>>>>>>
>>>>>>> I also noticed that you are adding a number of functions that don’t
>>>>>>> follow the naming convention of starting with a lowercase letter. I know
>>>>>>> there is a lot of code in clang that doesn’t follow that convention, and
>>>>>>> perhaps you are doing it that way on purpose to be consistent, but please
>>>>>>> review all the new function names and follow the coding standard, except
>>>>>>> for any cases where it clearly makes more sense to match the existing code.
>>>>>>>
>>>>>>> > @@ -807,6 +848,17 @@ static void emitRuntimeHook(CodeGenModule
>>>>>>> &CGM) {
>>>>>>> >    CGM.addUsedGlobal(User);
>>>>>>> >  }
>>>>>>> >
>>>>>>> > +void CodeGenPGO::checkGlobalDecl(GlobalDecl GD) {
>>>>>>> > +  // Make sure we only emit coverage mapping for one
>>>>>>> > +  // constructor/destructor
>>>>>>>
>>>>>>> Please elaborate on this comment to explain why it is an issue.
>>>>>>>
>>>>>>> > +  if ((isa<CXXConstructorDecl>(GD.getDecl()) &&
>>>>>>> > +       GD.getCtorType() != Ctor_Base) ||
>>>>>>> > +      (isa<CXXDestructorDecl>(GD.getDecl()) &&
>>>>>>> > +       GD.getDtorType() != Dtor_Base)) {
>>>>>>> > +    SkipCoverageMapping = true;
>>>>>>> > +  }
>>>>>>> > +}
>>>>>>> > +
>>>>>>> >  void CodeGenPGO::assignRegionCounters(const Decl *D,
>>>>>>> llvm::Function *Fn) {
>>>>>>> >    bool InstrumentRegions =
>>>>>>> CGM.getCodeGenOpts().ProfileInstrGenerate;
>>>>>>> >    llvm::IndexedInstrProfReader *PGOReader = CGM.getPGOReader();
>>>>>>>
>>>>>>>>>>>>>>
>>>>>>> > diff --git a/lib/CodeGen/CoverageMappingGen.cpp
>>>>>>> b/lib/CodeGen/CoverageMappingGen.cpp
>>>>>>> > new file mode 100644
>>>>>>> > index 0000000..ed65660
>>>>>>> > --- /dev/null
>>>>>>> > +++ b/lib/CodeGen/CoverageMappingGen.cpp
>>>>>>> > @@ -0,0 +1,1178 @@
>>>>>>> > +//===--- CoverageMappingGen.cpp - Coverage mapping generation
>>>>>>> ---*- C++ -*-===//
>>>>>>> > +//
>>>>>>> > +//                     The LLVM Compiler Infrastructure
>>>>>>> > +//
>>>>>>> > +// This file is distributed under the University of Illinois Open
>>>>>>> Source
>>>>>>> > +// License. See LICENSE.TXT for details.
>>>>>>> > +//
>>>>>>> >
>>>>>>> +//===----------------------------------------------------------------------===//
>>>>>>> > +//
>>>>>>> > +// Instrumentation-based code coverage mapping generator
>>>>>>> > +//
>>>>>>> >
>>>>>>> +//===----------------------------------------------------------------------===//
>>>>>>> > +
>>>>>>> > +#include "CoverageMappingGen.h"
>>>>>>> > +#include "CodeGenFunction.h"
>>>>>>> > +#include "clang/AST/RecursiveASTVisitor.h”
>>>>>>>
>>>>>>> I don’t see any direct use of RecursiveASTVisitor in this file. Is
>>>>>>> this #include really needed?
>>>>>>>
>>>>>>>>>>>>>>
>>>>>>> > +/// \brief A StmtVisitor that creates unreachable coverage
>>>>>>> regions for the
>>>>>>> > +/// functions that are not emitted.
>>>>>>> > +struct EmptyCoverageMappingBuilder : public
>>>>>>> CoverageMappingBuilder {
>>>>>>>
>>>>>>> The comment is wrong — this is not actually a StmtVisitor.
>>>>>>>
>>>>>>>>>>>>>>
>>>>>>> > +/// \brief A StmtVisitor that creates coverage mapping regions
>>>>>>> maps the
>>>>>>> > +/// source code locations to PGO counters.
>>>>>>> > +struct CounterCoverageMappingBuilder
>>>>>>> > +    : public CoverageMappingBuilder,
>>>>>>> > +      public ConstStmtVisitor<CounterCoverageMappingBuilder> {
>>>>>>>
>>>>>>> The comment here isn’t a proper sentence. Maybe you intended “maps”
>>>>>>> to be “that map”?
>>>>>>>
>>>>>>> The rest of this patch looks really good to me.
>>>>>>> _______________________________________________
>>>>>>> cfe-commits mailing list
>>>>>>> cfe-commits at cs.uiuc.edu
>>>>>>> http://lists.cs.uiuc.edu/mailman/listinfo/cfe-commits
>>>>>>>
>>>>>>
>>>>>> _______________________________________________
>>>>>> cfe-commits mailing list
>>>>>> cfe-commits at cs.uiuc.edu
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>>>>>>
>>>>>>
>>>>>>
>>>>>
>>>>
>>>>
>>> <clangCoverageMapping.patch>
>>>
>>>
>>>
>> <clangCoverageMapping.patch>
>>
>>
>>
>
>
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