r243987 - [Sema] Allocate SmallVector to the right size.

[Benjamin Kramer]

> On 04.08.2015, at 17:01, Yaron Keren <yaron.keren at gmail.com> wrote:
> 
> Did you mean TempParamLists never had more than four members?
> Anyhow, set_size should have asserted if its input is more than the capacity.

Yes, and was possible to trigger the assertion with something crazy like this:

  template <class T>
  struct X {
    template <class U>
    struct A {
      template <class V>
      struct B {
        template <class W>
        struct C {
          template <class X>
          struct D {
            template <class Y>
            struct E {
              template <class Z>
              void operator+=(Z);
            };
          };
        };
      };
    };

    template <class U>
    template <class V>
    template <class W>
    template <class X>
    template <class Y>
    template <class Z>
    friend void A<U>::template B<V>::template C<W>::template D<X>::template E<Y>::operator+=(Z);
  };

  void test() {
    X<int>::A<int>::B<int>::C<int>::D<int>::E<int>() += 1.0;
  }; 

I don't think that's valid C++ though. We have zero test coverage for TempParamLists.size() > 1.

- Ben

> 2015-08-04 17:46 GMT+03:00 Benjamin Kramer <benny.kra at googlemail.com>:
> Author: d0k
> Date: Tue Aug  4 09:46:06 2015
> New Revision: 243987
> 
> URL: http://llvm.org/viewvc/llvm-project?rev=243987&view=rev
> Log:
> [Sema] Allocate SmallVector to the right size.
> 
> SmallVector::set_size does not reallocate the vector. Sadly I have no
> idea how to test this. The vector never has more than one member in all
> of the regression tests.
> 
> Found by inspection.
> 
> Modified:
>     cfe/trunk/lib/Sema/SemaTemplateInstantiateDecl.cpp
> 
> Modified: cfe/trunk/lib/Sema/SemaTemplateInstantiateDecl.cpp
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaTemplateInstantiateDecl.cpp?rev=243987&r1=243986&r2=243987&view=diff
> ==============================================================================
> --- cfe/trunk/lib/Sema/SemaTemplateInstantiateDecl.cpp (original)
> +++ cfe/trunk/lib/Sema/SemaTemplateInstantiateDecl.cpp Tue Aug  4 09:46:06 2015
> @@ -1657,7 +1657,7 @@ TemplateDeclInstantiator::VisitCXXMethod
>    SmallVector<TemplateParameterList *, 4> TempParamLists;
>    unsigned NumTempParamLists = 0;
>    if (isFriend && (NumTempParamLists = D->getNumTemplateParameterLists())) {
> -    TempParamLists.set_size(NumTempParamLists);
> +    TempParamLists.resize(NumTempParamLists);
>      for (unsigned I = 0; I != NumTempParamLists; ++I) {
>        TemplateParameterList *TempParams = D->getTemplateParameterList(I);
>        TemplateParameterList *InstParams = SubstTemplateParams(TempParams);
> 
> 
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