maxjhandsome
/
llvm-project
forked from OSchip/llvm-project
1
0
Fork 0
Code Issues Pull Requests Packages Releases Wiki Activity

Implement the rvalue-reference deduction transformation (from T&& -> 

T) when taking the address of an overloaded function or matching a
specialization to a template (C++0x [temp.deduct.type]p10). Fixes
PR9044.

llvm-svn: 124197
This commit is contained in:
Douglas Gregor 2011-01-25 17:19:08 +00:00
parent 109941b078
commit 85f240c788
2 changed files with 37 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

39
clang/lib/Sema/SemaTemplateDeduction.cpp
View File

@ -49,7 +49,10 @@ namespace clang {
/// \brief Allow non-dependent types to differ, e.g., when performing
/// template argument deduction from a function call where conversions
/// may apply.
TDF_SkipNonDependent = 0x08
TDF_SkipNonDependent = 0x08,
/// \brief Whether we are performing template argument deduction for
/// parameters and arguments in a top-level template argument
TDF_TopLevelParameterTypeList = 0x10
};
}
@ -763,9 +766,9 @@ DeduceTemplateArguments(Sema &S,
// Deduce template arguments from the pattern.
if (Sema::TemplateDeductionResult Result
= DeduceTemplateArguments(S, TemplateParams, Pattern, Args[ArgIdx],
Info, Deduced, PartialOrdering,
RefParamComparisons))
= DeduceTemplateArguments(S, TemplateParams, Pattern, Args[ArgIdx],
Info, Deduced, TDF, PartialOrdering,
RefParamComparisons))
return Result;
// Capture the deduced template arguments for each parameter pack expanded
@ -898,6 +901,29 @@ DeduceTemplateArguments(Sema &S,
Arg.getCVRQualifiers());
Param = S.Context.getQualifiedType(UnqualParam, Quals);
}
if ((TDF & TDF_TopLevelParameterTypeList) && !Param->isFunctionType()) {
// C++0x [temp.deduct.type]p10:
// If P and A are function types that originated from deduction when
// taking the address of a function template (14.8.2.2) or when deducing
// template arguments from a function declaration (14.8.2.6) and Pi and
// Ai are parameters of the top-level parameter-type-list of P and A,
// respectively, Pi is adjusted if it is an rvalue reference to a
// cv-unqualified template parameter and Ai is an lvalue reference, in
// which case the type of Pi is changed to be the template parameter
// type (i.e., T&& is changed to simply T). [ Note: As a result, when
// Pi is T&& and Ai is X&, the adjusted Pi will be T, causing T to be
// deduced as X&. — end note ]
TDF &= ~TDF_TopLevelParameterTypeList;
if (const RValueReferenceType *ParamRef
= Param->getAs<RValueReferenceType>()) {
if (isa<TemplateTypeParmType>(ParamRef->getPointeeType()) &&
!ParamRef->getPointeeType().getQualifiers())
if (Arg->isLValueReferenceType())
Param = ParamRef->getPointeeType();
}
}
}
// If the parameter type is not dependent, there is nothing to deduce.
@ -1119,6 +1145,7 @@ DeduceTemplateArguments(Sema &S,
// T(*)()
// T(*)(T)
case Type::FunctionProto: {
unsigned SubTDF = TDF & TDF_TopLevelParameterTypeList;
const FunctionProtoType *FunctionProtoArg =
dyn_cast<FunctionProtoType>(Arg);
if (!FunctionProtoArg)
@ -1147,7 +1174,7 @@ DeduceTemplateArguments(Sema &S,
FunctionProtoParam->getNumArgs(),
FunctionProtoArg->arg_type_begin(),
FunctionProtoArg->getNumArgs(),
Info, Deduced, 0);
Info, Deduced, SubTDF);
}
case Type::InjectedClassName: {
@ -2767,7 +2794,7 @@ Sema::DeduceTemplateArguments(FunctionTemplateDecl *FunctionTemplate,
if (TemplateDeductionResult Result
= ::DeduceTemplateArguments(*this, TemplateParams,
FunctionType, ArgFunctionType, Info,
Deduced, 0))
Deduced, TDF_TopLevelParameterTypeList))
return Result;
}

4
clang/test/CXX/temp/temp.fct.spec/temp.deduct/temp.deduct.type/p10-0x.cpp Normal file
View File

@ -0,0 +1,4 @@
// RUN: %clang_cc1 -std=c++0x -fsyntax-only -verify %s
template<typename T> void f(T&&);
template<> void f(int&) { }
void (*fp)(int&) = &f;