From fcf1bf168329a22bfb1ef32c6d90d2ab9ffea26b Mon Sep 17 00:00:00 2001
From: Dmitry Polukhin <dmitry.polukhin@gmail.com>
Date: Wed, 9 Mar 2016 15:30:53 +0000
Subject: [PATCH 1/2] [GCC] PR23529 Sema part of attrbute abi_tag support
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Commit: Stephan Bergmann <sbergman@redhat.com>
CommitDate: Fri Jul 1 09:12:17 2016 +0200
Original patch by Stefan B├╝hler http://reviews.llvm.org/D12834
Difference between original and this one:
- fixed all comments in original code review
- added more tests, all new diagnostics now covered by tests
- moved abi_tag on re-declaration checks to Sema::mergeDeclAttributes
where they actually may work as designed
- clang-format + other stylistic changes
Mangle part will be sent for review as a separate patch.
Differential Revision: http://reviews.llvm.org/D17567
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@263015 91177308-0d34-0410-b5e6-96231b3b80d8
(cherry picked from commit 707118c24cbb8849f27204b27dddfe8213a3dbb5)
Conflicts:
include/clang/Basic/AttrDocs.td
include/clang/Basic/DiagnosticSemaKinds.td
include/clang/Sema/AttributeList.h
lib/Sema/SemaDeclAttr.cpp
plus a4a149223dcbe73632b037fd5694c8589d5ee8d5 "NFC fix documentation build by
rL263015"
plus 2a54cbaf170652dfda762cdbd0ddb004dd1c1d55 "NFC fix documentation build by
rL263015: This time I hope it will fix the build for real."
---
docs/ItaniumMangleAbiTags.rst | 107 +++++++++++++++++++++++++++++
docs/index.rst | 1 +
include/clang/Basic/Attr.td | 8 +++
include/clang/Basic/AttrDocs.td | 13 ++++
include/clang/Basic/DiagnosticSemaKinds.td | 10 ++-
include/clang/Sema/AttributeList.h | 3 +-
lib/Sema/SemaDecl.cpp | 18 +++++
lib/Sema/SemaDeclAttr.cpp | 39 +++++++++++
test/SemaCXX/attr-abi-tag-syntax.cpp | 43 ++++++++++++
9 files changed, 240 insertions(+), 2 deletions(-)
create mode 100644 docs/ItaniumMangleAbiTags.rst
create mode 100644 test/SemaCXX/attr-abi-tag-syntax.cpp
diff --git a/docs/ItaniumMangleAbiTags.rst b/docs/ItaniumMangleAbiTags.rst
new file mode 100644
index 0000000..2d65031
--- /dev/null
+++ b/docs/ItaniumMangleAbiTags.rst
@@ -0,0 +1,107 @@
+========
+ABI tags
+========
+
+Introduction
+============
+
+This text tries to describe gcc semantic for mangling "abi_tag" attributes
+described in https://gcc.gnu.org/onlinedocs/gcc/C_002b_002b-Attributes.html
+
+There is no guarantee the following rules are correct, complete or make sense
+in any way as they were determined empirically by experiments with gcc5.
+
+Declaration
+===========
+
+ABI tags are declared in an abi_tag attribute and can be applied to a
+function, variable, class or inline namespace declaration. The attribute takes
+one or more strings (called tags); the order does not matter.
+
+See https://gcc.gnu.org/onlinedocs/gcc/C_002b_002b-Attributes.html for
+details.
+
+Tags on an inline namespace are called "implicit tags", all other tags are
+"explicit tags".
+
+Mangling
+========
+
+All tags that are "active" on an <unqualified-name> are emitted after the
+<unqualified-name>, before <template-args> or <discriminator>, and are part of
+the same <substitution> the <unqualified-name> is.
+
+They are mangled as:
+
+.. code-block:: none
+
+ <abi-tags> ::= <abi-tag>* # sort by name
+ <abi-tag> ::= B <tag source-name>
+
+Example:
+
+.. code-block:: c++
+
+ __attribute__((abi_tag("test")))
+ void Func();
+ // gets mangled as: _Z4FuncB4testv (prettified as `Func[abi:test]()`)
+
+Active tags
+===========
+
+A namespace does not have any active tags. For types (class / struct / union /
+enum), the explicit tags are the active tags.
+
+For variables and functions, the active tags are the explicit tags plus any
+"required tags" which are not in the "available tags" set:
+
+.. code-block:: none
+
+ derived-tags := (required-tags - available-tags)
+ active-tags := explicit-tags + derived-tags
+
+Required tags for a function
+============================
+
+If a function is used as a local scope for another name, and is part of
+another function as local scope, it doesn't have any required tags.
+
+If a function is used as a local scope for a guard variable name, it doesn't
+have any required tags.
+
+Otherwise the function requires any implicit or explicit tag used in the name
+for the return type.
+
+Example:
+
+.. code-block:: c++
+
+ namespace A {
+ inline namespace B __attribute__((abi_tag)) {
+ struct C { int x; };
+ }
+ }
+
+ A::C foo(); // gets mangled as: _Z3fooB1Bv (prettified as `foo[abi:B]()`)
+
+Required tags for a variable
+============================
+
+A variable requires any implicit or explicit tag used in its type.
+
+Available tags
+==============
+
+All tags used in the prefix and in the template arguments for a name are
+available. Also, for functions, all tags from the <bare-function-type>
+(which might include the return type for template functions) are available.
+
+For <local-name>s all active tags used in the local part (<function-
+encoding>) are available, but not implicit tags which were not active.
+
+Implicit and explicit tags used in the <unqualified-name> for a function (as
+in the type of a cast operator) are NOT available.
+
+Example: a cast operator to std::string (which is
+std::__cxx11::basic_string<...>) will use 'cxx11' as an active tag, as it is
+required from the return type `std::string` but not available.
diff --git a/docs/index.rst b/docs/index.rst
index a0a70c0..e2dc857 100644
--- a/docs/index.rst
+++ b/docs/index.rst
@@ -75,6 +75,7 @@ Design Documents
DriverInternals
PTHInternals
PCHInternals
+ ItaniumMangleAbiTags
Indices and tables
diff --git a/include/clang/Basic/Attr.td b/include/clang/Basic/Attr.td
index d5ba722..82d5f5f 100644
--- a/include/clang/Basic/Attr.td
+++ b/include/clang/Basic/Attr.td
@@ -349,6 +349,14 @@ class IgnoredAttr : Attr {
// Attributes begin here
//
+def AbiTag : Attr {
+ let Spellings = [GCC<"abi_tag">];
+ let Args = [VariadicStringArgument<"Tags">];
+ let Subjects = SubjectList<[Struct, Var, Function, Namespace], ErrorDiag,
+ "ExpectedStructClassVariableFunctionOrInlineNamespace">;
+ let Documentation = [AbiTagsDocs];
+}
+
def AddressSpace : TypeAttr {
let Spellings = [GNU<"address_space">];
let Args = [IntArgument<"AddressSpace">];
diff --git a/include/clang/Basic/AttrDocs.td b/include/clang/Basic/AttrDocs.td
index 2567d55..ca82773 100644
--- a/include/clang/Basic/AttrDocs.td
+++ b/include/clang/Basic/AttrDocs.td
@@ -1859,3 +1859,16 @@ Marking virtual functions as ``disable_tail_calls`` is legal.
}];
}
+
+def AbiTagsDocs : Documentation {
+ let Content = [{
+The ``abi_tag`` attribute can be applied to a function, variable, class or
+inline namespace declaration to modify the mangled name of the entity. It gives
+the ability to distinguish between different versions of the same entity but
+with different ABI versions supported. For example, a newer version of a class
+could have a different set of data members and thus have a different size. Using
+the ``abi_tag`` attribute, it is possible to have different mangled names for
+a global variable of the class type. Therefor, the old code could keep using
+the old manged name and the new code will use the new mangled name with tags.
+ }];
+}
diff --git a/include/clang/Basic/DiagnosticSemaKinds.td b/include/clang/Basic/DiagnosticSemaKinds.td
index 6ba482c..b77e4bf 100644
--- a/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/include/clang/Basic/DiagnosticSemaKinds.td
@@ -2434,7 +2434,8 @@ def warn_attribute_wrong_decl_type : Warning<
"Objective-C instance methods|init methods of interface or class extension declarations|"
"variables, functions and classes|Objective-C protocols|"
"functions and global variables|structs, unions, and typedefs|structs and typedefs|"
- "interface or protocol declarations|kernel functions|non-K&R-style functions}1">,
+ "interface or protocol declarations|kernel functions|non-K&R-style functions|"
+ "structs, classes, variables, functions, and inline namespaces}1">,
InGroup<IgnoredAttributes>;
def err_attribute_wrong_decl_type : Error<warn_attribute_wrong_decl_type.Text>;
def warn_type_attribute_wrong_type : Warning<
@@ -4144,6 +4145,13 @@ def err_definition_of_explicitly_defaulted_member : Error<
def err_redefinition_extern_inline : Error<
"redefinition of a 'extern inline' function %0 is not supported in "
"%select{C99 mode|C++}1">;
+def warn_attr_abi_tag_namespace : Warning<
+ "'abi_tag' attribute on %select{non-inline|anonymous}0 namespace ignored">,
+ InGroup<IgnoredAttributes>;
+def err_abi_tag_on_redeclaration : Error<
+ "cannot add 'abi_tag' attribute in a redeclaration">;
+def err_new_abi_tag_on_redeclaration : Error<
+ "'abi_tag' %0 missing in original declaration">;
def note_deleted_dtor_no_operator_delete : Note<
"virtual destructor requires an unambiguous, accessible 'operator delete'">;
diff --git a/include/clang/Sema/AttributeList.h b/include/clang/Sema/AttributeList.h
index e32781d..755ef54 100644
--- a/include/clang/Sema/AttributeList.h
+++ b/include/clang/Sema/AttributeList.h
@@ -855,7 +855,8 @@ enum AttributeDeclKind {
ExpectedStructOrTypedef,
ExpectedObjectiveCInterfaceOrProtocol,
ExpectedKernelFunction,
- ExpectedFunctionWithProtoType
+ ExpectedFunctionWithProtoType,
+ ExpectedStructClassVariableFunctionOrInlineNamespace
};
} // end namespace clang
diff --git a/lib/Sema/SemaDecl.cpp b/lib/Sema/SemaDecl.cpp
index f95d106..681aadc 100644
--- a/lib/Sema/SemaDecl.cpp
+++ b/lib/Sema/SemaDecl.cpp
@@ -2396,6 +2396,24 @@ void Sema::mergeDeclAttributes(NamedDecl *New, Decl *Old,
}
}
+ // Re-declaration cannot add abi_tag's.
+ if (const auto *NewAbiTagAttr = New->getAttr<AbiTagAttr>()) {
+ if (const auto *OldAbiTagAttr = Old->getAttr<AbiTagAttr>()) {
+ for (const auto &NewTag : NewAbiTagAttr->tags()) {
+ if (std::find(OldAbiTagAttr->tags_begin(), OldAbiTagAttr->tags_end(),
+ NewTag) == OldAbiTagAttr->tags_end()) {
+ Diag(NewAbiTagAttr->getLocation(),
+ diag::err_new_abi_tag_on_redeclaration)
+ << NewTag;
+ Diag(OldAbiTagAttr->getLocation(), diag::note_previous_declaration);
+ }
+ }
+ } else {
+ Diag(NewAbiTagAttr->getLocation(), diag::err_abi_tag_on_redeclaration);
+ Diag(Old->getLocation(), diag::note_previous_declaration);
+ }
+ }
+
if (!Old->hasAttrs())
return;
diff --git a/lib/Sema/SemaDeclAttr.cpp b/lib/Sema/SemaDeclAttr.cpp
index f94c822..7214202 100644
--- a/lib/Sema/SemaDeclAttr.cpp
+++ b/lib/Sema/SemaDeclAttr.cpp
@@ -4446,6 +4446,42 @@ static void handleDeclspecThreadAttr(Sema &S, Decl *D,
Attr.getRange(), S.Context, Attr.getAttributeSpellingListIndex()));
}
+static void handleAbiTagAttr(Sema &S, Decl *D, const AttributeList &Attr) {
+ SmallVector<std::string, 4> Tags;
+ for (unsigned I = 0, E = Attr.getNumArgs(); I != E; ++I) {
+ StringRef Tag;
+ if (!S.checkStringLiteralArgumentAttr(Attr, I, Tag))
+ return;
+ Tags.push_back(Tag);
+ }
+
+ if (const auto *NS = dyn_cast<NamespaceDecl>(D)) {
+ if (!NS->isInline()) {
+ S.Diag(Attr.getLoc(), diag::warn_attr_abi_tag_namespace) << 0;
+ return;
+ }
+ if (NS->isAnonymousNamespace()) {
+ S.Diag(Attr.getLoc(), diag::warn_attr_abi_tag_namespace) << 1;
+ return;
+ }
+ if (Attr.getNumArgs() == 0)
+ Tags.push_back(NS->getName());
+ } else if (!checkAttributeAtLeastNumArgs(S, Attr, 1))
+ return;
+
+ // Store tags sorted and without duplicates.
+ std::sort(Tags.begin(), Tags.end());
+ Tags.erase(std::unique(Tags.begin(), Tags.end()), Tags.end());
+
+ D->addAttr(::new (S.Context)
+ AbiTagAttr(Attr.getRange(), S.Context, Tags.data(), Tags.size(),
+ Attr.getAttributeSpellingListIndex()));
+
+ // FIXME: remove this warning as soon as mangled part is ready.
+ S.Diag(Attr.getRange().getBegin(), diag::warn_attribute_ignored)
+ << Attr.getName();
+}
+
static void handleARMInterruptAttr(Sema &S, Decl *D,
const AttributeList &Attr) {
// Check the attribute arguments.
@@ -5360,6 +5396,9 @@ static void ProcessDeclAttribute(Sema &S, Scope *scope, Decl *D,
case AttributeList::AT_Thread:
handleDeclspecThreadAttr(S, D, Attr);
break;
+ case AttributeList::AT_AbiTag:
+ handleAbiTagAttr(S, D, Attr);
+ break;
// Thread safety attributes:
case AttributeList::AT_AssertExclusiveLock:
diff --git a/test/SemaCXX/attr-abi-tag-syntax.cpp b/test/SemaCXX/attr-abi-tag-syntax.cpp
new file mode 100644
index 0000000..4a4534a
--- /dev/null
+++ b/test/SemaCXX/attr-abi-tag-syntax.cpp
@@ -0,0 +1,43 @@
+// RUN: %clang_cc1 -std=c++11 -fsyntax-only -verify %s
+
+namespace N1 {
+
+namespace __attribute__((__abi_tag__)) {}
+// expected-warning@-1 {{'abi_tag' attribute on non-inline namespace ignored}}
+
+namespace N __attribute__((__abi_tag__)) {}
+// expected-warning@-1 {{'abi_tag' attribute on non-inline namespace ignored}}
+
+} // namespace N1
+
+namespace N2 {
+
+inline namespace __attribute__((__abi_tag__)) {}
+// expected-warning@-1 {{'abi_tag' attribute on anonymous namespace ignored}}
+
+inline namespace N __attribute__((__abi_tag__)) {}
+// FIXME: remove this warning as soon as attribute fully supported.
+// expected-warning@-2 {{'__abi_tag__' attribute ignored}}
+
+} // namespcace N2
+
+__attribute__((abi_tag("B", "A"))) extern int a1;
+// FIXME: remove this warning as soon as attribute fully supported.
+// expected-warning@-2 {{'abi_tag' attribute ignored}}
+
+__attribute__((abi_tag("A", "B"))) extern int a1;
+// expected-note@-1 {{previous declaration is here}}
+// FIXME: remove this warning as soon as attribute fully supported.
+// expected-warning@-3 {{'abi_tag' attribute ignored}}
+
+__attribute__((abi_tag("A", "C"))) extern int a1;
+// expected-error@-1 {{'abi_tag' C missing in original declaration}}
+// FIXME: remove this warning as soon as attribute fully supported.
+// expected-warning@-3 {{'abi_tag' attribute ignored}}
+
+extern int a2;
+// expected-note@-1 {{previous declaration is here}}
+__attribute__((abi_tag("A")))extern int a2;
+// expected-error@-1 {{cannot add 'abi_tag' attribute in a redeclaration}}
+// FIXME: remove this warning as soon as attribute fully supported.
+// expected-warning@-3 {{'abi_tag' attribute ignored}}
--
2.7.4