dblaikie created this revision.
As Mehdi put it, entities should either be
available_externally+weak_odr, or linkonce_odr+linkonce_odr. While some
functions are emitted a_e/weak, their local variables were emitted
a_e/linkonce_odr.
While it might be nice to emit them a_e/weak, the Itanium ABI (& best
guess at MSVC's behavior as well) requires the local to be
linkonce/linkonce.
https://reviews.llvm.org/D29233
Files:
lib/AST/ASTContext.cpp
test/CodeGenCXX/explicit-instantiation.cpp
Index: test/CodeGenCXX/explicit-instantiation.cpp
===================================================================
--- test/CodeGenCXX/explicit-instantiation.cpp
+++ test/CodeGenCXX/explicit-instantiation.cpp
@@ -5,6 +5,9 @@
// This check logically is attached to 'template int S<int>::i;' below.
// CHECK: @_ZN1SIiE1iE = weak_odr global i32
+// This check is logically attached to 'template int
ExportedStaticLocal::f<int>()' below.
+// CHECK-OPT: @_ZZN19ExportedStaticLocal1fIiEEvvE1i = linkonce_odr global
+
template<typename T, typename U, typename Result>
struct plus {
Result operator()(const T& t, const U& u) const;
@@ -153,3 +156,17 @@
template <typename T> void S<T>::g() {}
template <typename T> int S<T>::i;
template <typename T> void S<T>::S2::h() {}
+
+namespace ExportedStaticLocal {
+void sink(int&);
+template <typename T>
+inline void f() {
+ static int i;
+ sink(i);
+}
+// See the check line at the top of the file.
+extern template void f<int>();
+void use() {
+ f<int>();
+}
+}
Index: lib/AST/ASTContext.cpp
===================================================================
--- lib/AST/ASTContext.cpp
+++ lib/AST/ASTContext.cpp
@@ -8892,22 +8892,27 @@
return GVA_Internal;
if (VD->isStaticLocal()) {
- GVALinkage StaticLocalLinkage = GVA_DiscardableODR;
const DeclContext *LexicalContext = VD->getParentFunctionOrMethod();
while (LexicalContext && !isa<FunctionDecl>(LexicalContext))
LexicalContext = LexicalContext->getLexicalParent();
- // Let the static local variable inherit its linkage from the nearest
- // enclosing function.
- if (LexicalContext)
- StaticLocalLinkage =
- Context.GetGVALinkageForFunction(cast<FunctionDecl>(LexicalContext));
-
- // GVA_StrongODR function linkage is stronger than what we need,
- // downgrade to GVA_DiscardableODR.
- // This allows us to discard the variable if we never end up needing it.
- return StaticLocalLinkage == GVA_StrongODR ? GVA_DiscardableODR
- : StaticLocalLinkage;
+ // ObjC Blocks can create local variables that don't have a FunctionDecl
+ // LexicalContext.
+ if (!LexicalContext)
+ return GVA_DiscardableODR;
+
+ // Otherwise, let the static local variable inherit its linkage from the
+ // nearest enclosing function.
+ auto StaticLocalLinkage =
+ Context.GetGVALinkageForFunction(cast<FunctionDecl>(LexicalContext));
+
+ // Itanium ABI (& MSVC seems to do similarly) requires static locals in
+ // inline functions to be emitted anywhere they're needed, even if the
+ // function they are local to is emitted StrongODR/AvailableExternally.
+ if (StaticLocalLinkage == GVA_StrongODR ||
+ StaticLocalLinkage == GVA_AvailableExternally)
+ return GVA_DiscardableODR;
+ return StaticLocalLinkage;
}
// MSVC treats in-class initialized static data members as definitions.
Index: test/CodeGenCXX/explicit-instantiation.cpp
===================================================================
--- test/CodeGenCXX/explicit-instantiation.cpp
+++ test/CodeGenCXX/explicit-instantiation.cpp
@@ -5,6 +5,9 @@
// This check logically is attached to 'template int S<int>::i;' below.
// CHECK: @_ZN1SIiE1iE = weak_odr global i32
+// This check is logically attached to 'template int ExportedStaticLocal::f<int>()' below.
+// CHECK-OPT: @_ZZN19ExportedStaticLocal1fIiEEvvE1i = linkonce_odr global
+
template<typename T, typename U, typename Result>
struct plus {
Result operator()(const T& t, const U& u) const;
@@ -153,3 +156,17 @@
template <typename T> void S<T>::g() {}
template <typename T> int S<T>::i;
template <typename T> void S<T>::S2::h() {}
+
+namespace ExportedStaticLocal {
+void sink(int&);
+template <typename T>
+inline void f() {
+ static int i;
+ sink(i);
+}
+// See the check line at the top of the file.
+extern template void f<int>();
+void use() {
+ f<int>();
+}
+}
Index: lib/AST/ASTContext.cpp
===================================================================
--- lib/AST/ASTContext.cpp
+++ lib/AST/ASTContext.cpp
@@ -8892,22 +8892,27 @@
return GVA_Internal;
if (VD->isStaticLocal()) {
- GVALinkage StaticLocalLinkage = GVA_DiscardableODR;
const DeclContext *LexicalContext = VD->getParentFunctionOrMethod();
while (LexicalContext && !isa<FunctionDecl>(LexicalContext))
LexicalContext = LexicalContext->getLexicalParent();
- // Let the static local variable inherit its linkage from the nearest
- // enclosing function.
- if (LexicalContext)
- StaticLocalLinkage =
- Context.GetGVALinkageForFunction(cast<FunctionDecl>(LexicalContext));
-
- // GVA_StrongODR function linkage is stronger than what we need,
- // downgrade to GVA_DiscardableODR.
- // This allows us to discard the variable if we never end up needing it.
- return StaticLocalLinkage == GVA_StrongODR ? GVA_DiscardableODR
- : StaticLocalLinkage;
+ // ObjC Blocks can create local variables that don't have a FunctionDecl
+ // LexicalContext.
+ if (!LexicalContext)
+ return GVA_DiscardableODR;
+
+ // Otherwise, let the static local variable inherit its linkage from the
+ // nearest enclosing function.
+ auto StaticLocalLinkage =
+ Context.GetGVALinkageForFunction(cast<FunctionDecl>(LexicalContext));
+
+ // Itanium ABI (& MSVC seems to do similarly) requires static locals in
+ // inline functions to be emitted anywhere they're needed, even if the
+ // function they are local to is emitted StrongODR/AvailableExternally.
+ if (StaticLocalLinkage == GVA_StrongODR ||
+ StaticLocalLinkage == GVA_AvailableExternally)
+ return GVA_DiscardableODR;
+ return StaticLocalLinkage;
}
// MSVC treats in-class initialized static data members as definitions.
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