faisalv created this revision.
faisalv added reviewers: rsmith, hubert.reinterpretcast, aaron.ballman,
erik.pilkington.
faisalv added a subscriber: cfe-commits.
faisalv set the repository for this revision to rL LLVM.
faisalv added a project: clang-c.
This patch enables the following code:
auto L = [](int i) { return i; };
constexpr int (*fpi)(int) = L;
static_assert(fpi(3) == 3);
Repository:
rL LLVM
https://reviews.llvm.org/D22997
Files:
lib/AST/ExprConstant.cpp
lib/Sema/SemaLambda.cpp
test/SemaCXX/cxx1z-constexpr-lambdas.cpp
Index: test/SemaCXX/cxx1z-constexpr-lambdas.cpp
===================================================================
--- test/SemaCXX/cxx1z-constexpr-lambdas.cpp
+++ test/SemaCXX/cxx1z-constexpr-lambdas.cpp
@@ -46,5 +46,31 @@
} // end ns test_constexpr_call
+
+namespace test_conversion_function_for_non_capturing_lambdas {
+
+namespace ns1 {
+auto L = [](int i) { return i; };
+constexpr int (*fpi)(int) = L;
+static_assert(fpi(3) == 3);
+auto GL = [](auto a) { return a; };
+
+constexpr char (*fp2)(char) = GL;
+constexpr double (*fp3)(double) = GL;
+constexpr const char* (*fp4)(const char*) = GL;
+static_assert(fp2('3') == '3');
+static_assert(fp3(3.14) == 3.14);
+constexpr const char *Str = "abc";
+static_assert(fp4(Str) == Str);
+
+auto NCL = [](int i) { static int j; return j; }; //expected-note{{declared here}}
+constexpr int (*fp5)(int) = NCL;
+constexpr int I = //expected-error{{must be initialized by a constant expression}}
+ fp5(5); //expected-note{{non-constexpr function}}
+
+} // end ns1
+
+} // end ns test_conversion_function_for_non_capturing_lambdas
+
#endif // ndef CPP14_AND_EARLIER
Index: lib/Sema/SemaLambda.cpp
===================================================================
--- lib/Sema/SemaLambda.cpp
+++ lib/Sema/SemaLambda.cpp
@@ -1263,7 +1263,7 @@
ConvTy,
ConvTSI,
/*isInline=*/true, /*isExplicit=*/false,
- /*isConstexpr=*/false,
+ /*isConstexpr=*/S.getLangOpts().CPlusPlus1z,
CallOperator->getBody()->getLocEnd());
Conversion->setAccess(AS_public);
Conversion->setImplicit(true);
Index: lib/AST/ExprConstant.cpp
===================================================================
--- lib/AST/ExprConstant.cpp
+++ lib/AST/ExprConstant.cpp
@@ -4386,6 +4386,10 @@
Call.getLValueBase().dyn_cast<const ValueDecl*>());
if (!FD)
return Error(Callee);
+
+ // Don't call function pointers which have been cast to some other type.
+ if (!Info.Ctx.hasSameType(CalleeType->getPointeeType(), FD->getType()))
+ return Error(E);
// Overloaded operator calls to member functions are represented as normal
// calls with '*this' as the first argument.
@@ -4401,11 +4405,36 @@
return false;
This = &ThisVal;
Args = Args.slice(1);
+ } else if (MD && MD->isLambdaStaticInvoker()) {
+
+ // Map the static invoker for the lambda back to the call operator.
+ // Conveniently, we don't have to slice out the 'this' argument (as is
+ // being done for the non-static case), since a static member function
+ // doesn't have an implicit argument passed in.
+ const CXXRecordDecl *ClosureClass = MD->getParent();
+ // number of captures better be zero.
+ assert(std::distance(ClosureClass->captures_begin(),
+ ClosureClass->captures_end()) == 0);
+ const CXXMethodDecl *LambdaCallOp = ClosureClass->getLambdaCallOperator();
+
+ // Set 'FD', the function that will be called below, to the call
+ // operator. If the closure object represents a generic lambda, find
+ // the corresponding specialization of the call operator.
+
+ if (ClosureClass->isGenericLambda()) {
+ assert(MD->isFunctionTemplateSpecialization());
+ const TemplateArgumentList *TAL = MD->getTemplateSpecializationArgs();
+ FunctionTemplateDecl *CallOpTemplate =
+ LambdaCallOp->getDescribedFunctionTemplate();
+ void *InsertPos = nullptr;
+ FunctionDecl *CorrespondingCallOpSpecialization =
+ CallOpTemplate->findSpecialization(TAL->asArray(), InsertPos);
+ assert(CorrespondingCallOpSpecialization);
+ FD = cast<CXXMethodDecl>(CorrespondingCallOpSpecialization);
+ } else
+ FD = LambdaCallOp;
}
-
- // Don't call function pointers which have been cast to some other type.
- if (!Info.Ctx.hasSameType(CalleeType->getPointeeType(), FD->getType()))
- return Error(E);
+
} else
return Error(E);
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