From ffc63a8f8ca7c2ccc525c876aa9ba9031176f782 Mon Sep 17 00:00:00 2001 From: Faisal Vali Date: Tue, 8 Oct 2013 04:15:04 +0000 Subject: [PATCH] Fix linkage calculation of auto member functions returning lambdas As described by Richard in https://groups.google.com/a/isocpp.org/d/msg/std-discussion/S1kmj0wF5-g/fb6agEYoL2IJ we should allow: template struct A { template static auto default_lambda() { return [](const T&) { return 42; }; } template())> U func(U u = default_lambda()) { return u; } }; int run2 = A{}.func()(3.14); int run3 = A{}.func()('a'); This patch allows the code using the same trickery that was used to allow the code in non-member functions at namespace scope. Please see http://llvm-reviews.chandlerc.com/D1844 for richard's approval. git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@192166 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/AST/Decl.cpp | 21 +++-- ...mbda-expressions-inside-auto-functions.cpp | 77 +++++++++++++++++++ 2 files changed, 93 insertions(+), 5 deletions(-) create mode 100644 test/CodeGenCXX/lambda-expressions-inside-auto-functions.cpp diff --git a/lib/AST/Decl.cpp b/lib/AST/Decl.cpp index 6ec1472000..f14e4dc7f4 100644 --- a/lib/AST/Decl.cpp +++ b/lib/AST/Decl.cpp @@ -702,8 +702,8 @@ static LinkageInfo getLVForNamespaceScopeDecl(const NamedDecl *D, // require looking at the linkage of this function, and we don't need this // for correctness because the type is not part of the function's // signature. - // FIXME: This is a hack. We should be able to solve this circularity some - // other way. + // FIXME: This is a hack. We should be able to solve this circularity and + // the one in getLVForClassMember for Functions some other way. QualType TypeAsWritten = Function->getType(); if (TypeSourceInfo *TSI = Function->getTypeSourceInfo()) TypeAsWritten = TSI->getType(); @@ -830,9 +830,20 @@ static LinkageInfo getLVForClassMember(const NamedDecl *D, if (const CXXMethodDecl *MD = dyn_cast(D)) { // If the type of the function uses a type with unique-external // linkage, it's not legally usable from outside this translation unit. - if (MD->getType()->getLinkage() == UniqueExternalLinkage) - return LinkageInfo::uniqueExternal(); - + // But only look at the type-as-written. If this function has an auto-deduced + // return type, we can't compute the linkage of that type because it could + // require looking at the linkage of this function, and we don't need this + // for correctness because the type is not part of the function's + // signature. + // FIXME: This is a hack. We should be able to solve this circularity and the + // one in getLVForNamespaceScopeDecl for Functions some other way. + { + QualType TypeAsWritten = MD->getType(); + if (TypeSourceInfo *TSI = MD->getTypeSourceInfo()) + TypeAsWritten = TSI->getType(); + if (TypeAsWritten->getLinkage() == UniqueExternalLinkage) + return LinkageInfo::uniqueExternal(); + } // If this is a method template specialization, use the linkage for // the template parameters and arguments. if (FunctionTemplateSpecializationInfo *spec diff --git a/test/CodeGenCXX/lambda-expressions-inside-auto-functions.cpp b/test/CodeGenCXX/lambda-expressions-inside-auto-functions.cpp new file mode 100644 index 0000000000..0083f0826e --- /dev/null +++ b/test/CodeGenCXX/lambda-expressions-inside-auto-functions.cpp @@ -0,0 +1,77 @@ +// RUN: %clang_cc1 -triple x86_64-apple-darwin10.0.0 -fblocks -emit-llvm -o - %s -fexceptions -std=c++1y | FileCheck %s + +// CHECK-LABEL: define void @_ZN19non_inline_function3fooEv +// CHECK-LABEL: define internal void @"_ZZN19non_inline_function3fooEvENK3$_0clEi"(%class.anon +// CHECK-LABEL: define internal signext i8 @"_ZZZN19non_inline_function3fooEvENK3$_0clEiENKUlcE_clEc"(%class.anon +// CHECK-LABEL: define linkonce_odr void @_ZN19non_inline_function4foo2IiEEDav() +namespace non_inline_function { +auto foo() { + auto L = [](int a) { + return [](char b) { + return b; + }; + }; + L(3)('a'); + return L; +} + +template +auto foo2() { + return [](const T&) { return 42; }; +} + +auto use = foo2(); + +} +//CHECK-LABEL: define linkonce_odr void @_ZN22inline_member_function1X3fooEv(%"struct.inline_member_function::X"* %this) +//CHECK-LABEL: define linkonce_odr void @_ZZN22inline_member_function1X3fooEvENKUliE_clEi(%class.anon +//CHECK-LABEL: define linkonce_odr signext i8 @_ZZZN22inline_member_function1X3fooEvENKUliE_clEiENKUlcE_clEc(%class.anon + +namespace inline_member_function { +struct X { +auto foo() { + auto L = [](int a) { + return [](char b) { + return b; + }; + }; + return L; +} +}; + +auto run1 = X{}.foo()(3)('a'); + +template +struct A { + template static auto default_lambda() { + return [](const T&) { return 42; }; + } + + template())> + U func(U u = default_lambda()) { return u; } + + template auto foo() { return [](const T&) { return 42; }; } +}; +//CHECK-LABEL: define linkonce_odr i32 @_ZZN22inline_member_function1AIdE14default_lambdaIdEEDavENKUlRKdE_clES5_(%class.anon +int run2 = A{}.func()(3.14); + +//CHECK-LABEL: define linkonce_odr i32 @_ZZN22inline_member_function1AIcE14default_lambdaIcEEDavENKUlRKcE_clES5_(%class.anon +int run3 = A{}.func()('a'); +} // end inline_member_function + + +// CHECK-LABEL: define linkonce_odr void @_ZN15inline_function3fooEv() +// CHECK: define linkonce_odr void @_ZZN15inline_function3fooEvENKUliE_clEi(%class.anon +// CHECK: define linkonce_odr signext i8 @_ZZZN15inline_function3fooEvENKUliE_clEiENKUlcE_clEc(%class.anon +namespace inline_function { +inline auto foo() { + auto L = [](int a) { + return [](char b) { + return b; + }; + }; + return L; +} +auto use = foo()(3)('a'); +} + -- 2.40.0