r181669 - C++1y: provide full 'auto' return type deduction for lambda expressions. This
Richard Smith
richard-llvm at metafoo.co.uk
Sat May 11 20:09:36 PDT 2013
Author: rsmith
Date: Sat May 11 22:09:35 2013
New Revision: 181669
URL: http://llvm.org/viewvc/llvm-project?rev=181669&view=rev
Log:
C++1y: provide full 'auto' return type deduction for lambda expressions. This
completes the implementation of N3638.
Added:
cfe/trunk/test/CXX/dcl.dcl/dcl.spec/dcl.type/dcl.spec.auto/p12-1y.cpp
cfe/trunk/test/CXX/expr/expr.prim/expr.prim.lambda/p4-1y.cpp
Modified:
cfe/trunk/docs/LanguageExtensions.rst
cfe/trunk/lib/Lex/PPMacroExpansion.cpp
cfe/trunk/lib/Sema/SemaStmt.cpp
cfe/trunk/test/CXX/expr/expr.prim/expr.prim.lambda/p4.cpp
cfe/trunk/test/Lexer/has_feature_cxx0x.cpp
cfe/trunk/www/cxx_status.html
Modified: cfe/trunk/docs/LanguageExtensions.rst
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/docs/LanguageExtensions.rst?rev=181669&r1=181668&r2=181669&view=diff
==============================================================================
--- cfe/trunk/docs/LanguageExtensions.rst (original)
+++ cfe/trunk/docs/LanguageExtensions.rst Sat May 11 22:09:35 2013
@@ -852,7 +852,6 @@ Use ``__has_feature(cxx_return_type_dedu
``__has_extension(cxx_return_type_deduction)`` to determine if support
for return type deduction for functions (using ``auto`` as a return type)
is enabled.
-Clang's implementation of this feature is incomplete.
C++1y runtime-sized arrays
^^^^^^^^^^^^^^^^^^^^^^^^^^
Modified: cfe/trunk/lib/Lex/PPMacroExpansion.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Lex/PPMacroExpansion.cpp?rev=181669&r1=181668&r2=181669&view=diff
==============================================================================
--- cfe/trunk/lib/Lex/PPMacroExpansion.cpp (original)
+++ cfe/trunk/lib/Lex/PPMacroExpansion.cpp Sat May 11 22:09:35 2013
@@ -798,7 +798,7 @@ static bool HasFeature(const Preprocesso
//.Case("cxx_generalized_capture", LangOpts.CPlusPlus1y)
//.Case("cxx_generic_lambda", LangOpts.CPlusPlus1y)
//.Case("cxx_relaxed_constexpr", LangOpts.CPlusPlus1y)
- //.Case("cxx_return_type_deduction", LangOpts.CPlusPlus1y)
+ .Case("cxx_return_type_deduction", LangOpts.CPlusPlus1y)
//.Case("cxx_runtime_array", LangOpts.CPlusPlus1y)
.Case("cxx_aggregate_nsdmi", LangOpts.CPlusPlus1y)
//.Case("cxx_variable_templates", LangOpts.CPlusPlus1y)
Modified: cfe/trunk/lib/Sema/SemaStmt.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaStmt.cpp?rev=181669&r1=181668&r2=181669&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaStmt.cpp (original)
+++ cfe/trunk/lib/Sema/SemaStmt.cpp Sat May 11 22:09:35 2013
@@ -2362,22 +2362,37 @@ Sema::PerformMoveOrCopyInitialization(co
StmtResult
Sema::ActOnCapScopeReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp) {
// If this is the first return we've seen, infer the return type.
- // [expr.prim.lambda]p4 in C++11; block literals follow a superset of those
- // rules which allows multiple return statements.
+ // [expr.prim.lambda]p4 in C++11; block literals follow the same rules.
CapturingScopeInfo *CurCap = cast<CapturingScopeInfo>(getCurFunction());
QualType FnRetType = CurCap->ReturnType;
// For blocks/lambdas with implicit return types, we check each return
// statement individually, and deduce the common return type when the block
// or lambda is completed.
- if (CurCap->HasImplicitReturnType) {
+ if (AutoType *AT =
+ FnRetType.isNull() ? 0 : FnRetType->getContainedAutoType()) {
+ // In C++1y, the return type may involve 'auto'.
+ FunctionDecl *FD = cast<LambdaScopeInfo>(CurCap)->CallOperator;
+ if (CurContext->isDependentContext()) {
+ // C++1y [dcl.spec.auto]p12:
+ // Return type deduction [...] occurs when the definition is
+ // instantiated even if the function body contains a return
+ // statement with a non-type-dependent operand.
+ CurCap->ReturnType = FnRetType = Context.DependentTy;
+ } else if (DeduceFunctionTypeFromReturnExpr(FD, ReturnLoc, RetValExp, AT)) {
+ FD->setInvalidDecl();
+ return StmtError();
+ } else
+ CurCap->ReturnType = FnRetType = FD->getResultType();
+ } else if (CurCap->HasImplicitReturnType) {
+ // FIXME: Fold this into the 'auto' codepath above.
if (RetValExp && !isa<InitListExpr>(RetValExp)) {
ExprResult Result = DefaultFunctionArrayLvalueConversion(RetValExp);
if (Result.isInvalid())
return StmtError();
RetValExp = Result.take();
- if (!RetValExp->isTypeDependent())
+ if (!CurContext->isDependentContext())
FnRetType = RetValExp->getType();
else
FnRetType = CurCap->ReturnType = Context.DependentTy;
@@ -2553,7 +2568,6 @@ Sema::ActOnReturnStmt(SourceLocation Ret
if (RetValExp && DiagnoseUnexpandedParameterPack(RetValExp))
return StmtError();
- // FIXME: Unify this and C++1y auto function handling.
if (isa<CapturingScopeInfo>(getCurFunction()))
return ActOnCapScopeReturnStmt(ReturnLoc, RetValExp);
Added: cfe/trunk/test/CXX/dcl.dcl/dcl.spec/dcl.type/dcl.spec.auto/p12-1y.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CXX/dcl.dcl/dcl.spec/dcl.type/dcl.spec.auto/p12-1y.cpp?rev=181669&view=auto
==============================================================================
--- cfe/trunk/test/CXX/dcl.dcl/dcl.spec/dcl.type/dcl.spec.auto/p12-1y.cpp (added)
+++ cfe/trunk/test/CXX/dcl.dcl/dcl.spec/dcl.type/dcl.spec.auto/p12-1y.cpp Sat May 11 22:09:35 2013
@@ -0,0 +1,17 @@
+// RUN: %clang_cc1 -std=c++11 -verify %s
+// RUN: %clang_cc1 -std=c++1y -verify %s
+
+template<typename T> struct S { typedef int type; };
+
+template<typename T> void f() {
+ auto x = [] { return 0; } ();
+ // FIXME: We should be able to produce a 'missing typename' diagnostic here.
+ S<decltype(x)>::type n; // expected-error 2{{}}
+}
+
+#if __cplusplus > 201103L
+template<typename T> void g() {
+ auto x = [] () -> auto { return 0; } ();
+ S<decltype(x)>::type n; // expected-error 2{{}}
+}
+#endif
Added: cfe/trunk/test/CXX/expr/expr.prim/expr.prim.lambda/p4-1y.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CXX/expr/expr.prim/expr.prim.lambda/p4-1y.cpp?rev=181669&view=auto
==============================================================================
--- cfe/trunk/test/CXX/expr/expr.prim/expr.prim.lambda/p4-1y.cpp (added)
+++ cfe/trunk/test/CXX/expr/expr.prim/expr.prim.lambda/p4-1y.cpp Sat May 11 22:09:35 2013
@@ -0,0 +1,9 @@
+// RUN: %clang_cc1 -fsyntax-only -std=c++1y %s -verify
+
+int a;
+int &b = [] (int &r) -> decltype(auto) { return r; } (a);
+int &c = [] (int &r) -> decltype(auto) { return (r); } (a);
+int &d = [] (int &r) -> auto & { return r; } (a);
+int &e = [] (int &r) -> auto { return r; } (a); // expected-error {{cannot bind to a temporary}}
+int &f = [] (int r) -> decltype(auto) { return r; } (a); // expected-error {{cannot bind to a temporary}}
+int &g = [] (int r) -> decltype(auto) { return (r); } (a); // expected-warning {{reference to stack}}
Modified: cfe/trunk/test/CXX/expr/expr.prim/expr.prim.lambda/p4.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CXX/expr/expr.prim/expr.prim.lambda/p4.cpp?rev=181669&r1=181668&r2=181669&view=diff
==============================================================================
--- cfe/trunk/test/CXX/expr/expr.prim/expr.prim.lambda/p4.cpp (original)
+++ cfe/trunk/test/CXX/expr/expr.prim/expr.prim.lambda/p4.cpp Sat May 11 22:09:35 2013
@@ -1,4 +1,5 @@
// RUN: %clang_cc1 -fsyntax-only -std=c++11 %s -verify
+// RUN: %clang_cc1 -fsyntax-only -std=c++1y %s -verify
void missing_lambda_declarator() {
[](){}();
Modified: cfe/trunk/test/Lexer/has_feature_cxx0x.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Lexer/has_feature_cxx0x.cpp?rev=181669&r1=181668&r2=181669&view=diff
==============================================================================
--- cfe/trunk/test/Lexer/has_feature_cxx0x.cpp (original)
+++ cfe/trunk/test/Lexer/has_feature_cxx0x.cpp Sat May 11 22:09:35 2013
@@ -346,3 +346,13 @@ int no_aggregate_nsdmi();
// CHECK-1Y: has_aggregate_nsdmi
// CHECK-11: no_aggregate_nsdmi
// CHECK-NO-11: no_aggregate_nsdmi
+
+#if __has_feature(cxx_return_type_deduction)
+int has_return_type_deduction();
+#else
+int no_return_type_deduction();
+#endif
+
+// CHECK-1Y: has_return_type_deduction
+// CHECK-11: no_return_type_deduction
+// CHECK-NO-11: no_return_type_deduction
Modified: cfe/trunk/www/cxx_status.html
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/www/cxx_status.html?rev=181669&r1=181668&r2=181669&view=diff
==============================================================================
--- cfe/trunk/www/cxx_status.html (original)
+++ cfe/trunk/www/cxx_status.html Sat May 11 22:09:35 2013
@@ -431,7 +431,7 @@ available.</p>
</tr>
<tr>
<td>Return type deduction for normal functions</td>
- <td class="partial" align="center">Partial</td>
+ <td class="svn" align="center">SVN</td>
</tr>
<tr>
<td>Runtime-sized arrays with automatic storage duration</td>
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