r205543 - Teach getTemplateInstantiationPattern to deal with generic lambdas.

[Richard Smith]

Thanks!


On Thu, Apr 3, 2014 at 9:32 AM, Faisal Vali <faisalv at yahoo.com> wrote:

> Author: faisalv
> Date: Thu Apr  3 11:32:21 2014
> New Revision: 205543
>
> URL: http://llvm.org/viewvc/llvm-project?rev=205543&view=rev
> Log:
> Teach getTemplateInstantiationPattern to deal with generic lambdas.
>
> No functionality change.
>
> When determining the pattern for instantiating a generic lambda call
> operator specialization - we must not go drilling down for the 'prototype'
> (i.e. as written) pattern - rather we must use our partially transformed
>  pattern (whose DeclRefExprs are wired correctly to any enclosing lambda's
> decls that should be mapped correctly in a local instantiation scope) that
> is the templated pattern of the specialization's primary template (even
> though the primary template might be instantiated from a 'prototype'
> member-template).  Previously, the drilling down was haltted by marking the
> instantiated-from primary template as a member-specialization (incorrectly).
>
> This prompted Richard to remark (
> http://llvm-reviews.chandlerc.com/D1784?id=4687#inline-10272)
> "It's a bit nasty to (essentially) set this bit incorrectly. Can you put
> the check into getTemplateInstantiationPattern instead?"
>
> In my reckless youth, I chose to ignore that comment.  With the passage of
> time, I have come to learn the value of bowing to the will of the angry
> Gods ;)
>
>
>
> Modified:
>     cfe/trunk/include/clang/AST/ASTLambda.h
>     cfe/trunk/lib/AST/Decl.cpp
>     cfe/trunk/lib/Sema/SemaTemplateInstantiate.cpp
>
> Modified: cfe/trunk/include/clang/AST/ASTLambda.h
> URL:
> http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/AST/ASTLambda.h?rev=205543&r1=205542&r2=205543&view=diff
>
> ==============================================================================
> --- cfe/trunk/include/clang/AST/ASTLambda.h (original)
> +++ cfe/trunk/include/clang/AST/ASTLambda.h Thu Apr  3 11:32:21 2014
> @@ -36,9 +36,9 @@ inline bool isLambdaCallOperator(const D
>    return isLambdaCallOperator(cast<CXXMethodDecl>(DC));
>  }
>
> -inline bool isGenericLambdaCallOperatorSpecialization(CXXMethodDecl *MD) {
> +inline bool isGenericLambdaCallOperatorSpecialization(const CXXMethodDecl
> *MD) {
>    if (!MD) return false;
> -  CXXRecordDecl *LambdaClass = MD->getParent();
> +  const CXXRecordDecl *LambdaClass = MD->getParent();
>    if (LambdaClass && LambdaClass->isGenericLambda())
>      return isLambdaCallOperator(MD) &&
>                      MD->isFunctionTemplateSpecialization();
>
> Modified: cfe/trunk/lib/AST/Decl.cpp
> URL:
> http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/AST/Decl.cpp?rev=205543&r1=205542&r2=205543&view=diff
>
> ==============================================================================
> --- cfe/trunk/lib/AST/Decl.cpp (original)
> +++ cfe/trunk/lib/AST/Decl.cpp Thu Apr  3 11:32:21 2014
> @@ -13,6 +13,7 @@
>
>  #include "clang/AST/Decl.h"
>  #include "clang/AST/ASTContext.h"
> +#include "clang/AST/ASTLambda.h"
>  #include "clang/AST/ASTMutationListener.h"
>  #include "clang/AST/Attr.h"
>  #include "clang/AST/DeclCXX.h"
> @@ -2830,14 +2831,34 @@ FunctionDecl *FunctionDecl::getTemplateI
>    // Handle class scope explicit specialization special case.
>    if (getTemplateSpecializationKind() == TSK_ExplicitSpecialization)
>      return getClassScopeSpecializationPattern();
> -
> +
> +  // If this is a generic lambda call operator specialization, its
> +  // instantiation pattern is always its primary template's pattern
> +  // even if its primary template was instantiated from another
> +  // member template (which happens with nested generic lambdas).
> +  // Since a lambda's call operator's body is transformed eagerly,
> +  // we don't have to go hunting for a prototype definition template
> +  // (i.e. instantiated-from-member-template) to use as an instantiation
> +  // pattern.
> +
> +  if (isGenericLambdaCallOperatorSpecialization(
> +          dyn_cast<CXXMethodDecl>(this))) {
> +    assert(getPrimaryTemplate() && "A generic lambda specialization must
> be "
> +                                   "generated from a primary call
> operator "
> +                                   "template");
> +    assert(getPrimaryTemplate()->getTemplatedDecl()->getBody() &&
> +           "A generic lambda call operator template must always have a
> body - "
> +           "even if instantiated from a prototype (i.e. as written)
> member "
> +           "template");
> +    return getPrimaryTemplate()->getTemplatedDecl();
> +  }
> +
>    if (FunctionTemplateDecl *Primary = getPrimaryTemplate()) {
>      while (Primary->getInstantiatedFromMemberTemplate()) {
>        // If we have hit a point where the user provided a specialization
> of
>        // this template, we're done looking.
>        if (Primary->isMemberSpecialization())
>          break;
> -
>        Primary = Primary->getInstantiatedFromMemberTemplate();
>      }
>
>
> Modified: cfe/trunk/lib/Sema/SemaTemplateInstantiate.cpp
> URL:
> http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaTemplateInstantiate.cpp?rev=205543&r1=205542&r2=205543&view=diff
>
> ==============================================================================
> --- cfe/trunk/lib/Sema/SemaTemplateInstantiate.cpp (original)
> +++ cfe/trunk/lib/Sema/SemaTemplateInstantiate.cpp Thu Apr  3 11:32:21 2014
> @@ -837,8 +837,6 @@ namespace {
>
>  OldCallOperator->getDescribedFunctionTemplate();
>          NewCallOperatorTemplate->setInstantiatedFromMemberTemplate(
>
> OldCallOperatorTemplate);
> -        // Mark the NewCallOperatorTemplate a specialization.
> -        NewCallOperatorTemplate->setMemberSpecialization();
>        } else
>          // For a non-generic lambda we set the NewCallOperator to
>          // be an instantiation of the OldCallOperator.
>
>
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