[llvm-branch-commits] [cfe-branch] r182337 - Merging r182266:
Reid Kleckner
rnk at google.com
Tue May 21 11:09:23 PDT 2013
Erik Schwiebert requested it, since apparently it makes it significantly
easier for him to port code over to Clang from MSVC. I figured it would be
OK since before this change using selectany would lead to link errors, so
this should strictly fix code. I forgot to think about the code drift
between 3.3 and TOT.
On Tue, May 21, 2013 at 1:39 PM, Richard Smith <richard at metafoo.co.uk>wrote:
> Why was this change merged to the branch at all?
>
> On Tue, May 21, 2013 at 5:00 AM, NAKAMURA Takumi <geek4civic at gmail.com>wrote:
>
>> Bill and Reid, it depends on r181677 and r182096. release_33 has been
>> broken.
>>
>> SemaDeclAttr.cpp: In function ‘void handleSelectAnyAttr(clang::Sema&,
>> clang::Decl*, const clang::AttributeList&)’:
>> SemaDeclAttr.cpp:4687:33: error: ‘checkMicrosoftExt’ was not declared
>> in this scope
>>
>> SemaDecl.cpp: In function ‘void
>> checkAttributesAfterMerging(clang::Sema&, clang::NamedDecl&)’:
>> SemaDecl.cpp:4645:38: error: ‘class clang::NamedDecl’ has no member
>> named ‘isExternallyVisible’
>>
>> ...Takumi
>>
>>
>> 2013/5/21 Bill Wendling <isanbard at gmail.com>:
>> > Author: void
>> > Date: Mon May 20 19:06:11 2013
>> > New Revision: 182337
>> >
>> > URL: http://llvm.org/viewvc/llvm-project?rev=182337&view=rev
>> > Log:
>> > Merging r182266:
>> > ------------------------------------------------------------------------
>> > r182266 | rnk | 2013-05-20 07:02:37 -0700 (Mon, 20 May 2013) | 13 lines
>> >
>> > Implement __declspec(selectany) under -fms-extensions
>> >
>> > selectany only applies to externally visible global variables. It has
>> > the effect of making the data weak_odr.
>> >
>> > The MSDN docs suggest that unused definitions can only be dropped at
>> > linktime, so Clang uses weak instead of linkonce. MSVC optimizes away
>> > references to constant selectany data, so it must assume that there is
>> > only one definition, hence weak_odr.
>> >
>> > Reviewers: espindola
>> >
>> > Differential Revision: http://llvm-reviews.chandlerc.com/D814
>> > ------------------------------------------------------------------------
>> >
>> > Added:
>> > cfe/branches/release_33/test/SemaCXX/attr-selectany.cpp
>> > - copied unchanged from r182266,
>> cfe/trunk/test/SemaCXX/attr-selectany.cpp
>> > Modified:
>> > cfe/branches/release_33/ (props changed)
>> > cfe/branches/release_33/include/clang/Basic/Attr.td
>> > cfe/branches/release_33/include/clang/Basic/DiagnosticSemaKinds.td
>> > cfe/branches/release_33/lib/CodeGen/CodeGenModule.cpp
>> > cfe/branches/release_33/lib/Sema/SemaDecl.cpp
>> > cfe/branches/release_33/lib/Sema/SemaDeclAttr.cpp
>> > cfe/branches/release_33/test/CodeGen/ms-declspecs.c
>> >
>> > Propchange: cfe/branches/release_33/
>> >
>> ------------------------------------------------------------------------------
>> > --- svn:mergeinfo (original)
>> > +++ svn:mergeinfo Mon May 20 19:06:11 2013
>> > @@ -1,4 +1,4 @@
>> > /cfe/branches/type-system-rewrite:134693-134817
>> > -/cfe/trunk:181286,181299,181368,181465,181728,181750,181909,182072
>> >
>> +/cfe/trunk:181286,181299,181368,181465,181728,181750,181909,182072,182266
>> > /cfe/trunk/test:170344
>> > /cfe/trunk/test/SemaTemplate:126920
>> >
>> > Modified: cfe/branches/release_33/include/clang/Basic/Attr.td
>> > URL:
>> http://llvm.org/viewvc/llvm-project/cfe/branches/release_33/include/clang/Basic/Attr.td?rev=182337&r1=182336&r2=182337&view=diff
>> >
>> ==============================================================================
>> > --- cfe/branches/release_33/include/clang/Basic/Attr.td (original)
>> > +++ cfe/branches/release_33/include/clang/Basic/Attr.td Mon May 20
>> 19:06:11 2013
>> > @@ -948,6 +948,10 @@ def ForceInline : InheritableAttr {
>> > let Spellings = [Keyword<"__forceinline">];
>> > }
>> >
>> > +def SelectAny : InheritableAttr {
>> > + let Spellings = [Declspec<"selectany">];
>> > +}
>> > +
>> > def Win64 : InheritableAttr {
>> > let Spellings = [Keyword<"__w64">];
>> > }
>> >
>> > Modified:
>> cfe/branches/release_33/include/clang/Basic/DiagnosticSemaKinds.td
>> > URL:
>> http://llvm.org/viewvc/llvm-project/cfe/branches/release_33/include/clang/Basic/DiagnosticSemaKinds.td?rev=182337&r1=182336&r2=182337&view=diff
>> >
>> ==============================================================================
>> > --- cfe/branches/release_33/include/clang/Basic/DiagnosticSemaKinds.td
>> (original)
>> > +++ cfe/branches/release_33/include/clang/Basic/DiagnosticSemaKinds.td
>> Mon May 20 19:06:11 2013
>> > @@ -1948,6 +1948,8 @@ def warn_weak_identifier_undeclared : Wa
>> > "weak identifier %0 never declared">;
>> > def err_attribute_weak_static : Error<
>> > "weak declaration cannot have internal linkage">;
>> > +def err_attribute_selectany_non_extern_data : Error<
>> > + "'selectany' can only be applied to data items with external
>> linkage">;
>> > def warn_attribute_weak_import_invalid_on_definition : Warning<
>> > "'weak_import' attribute cannot be specified on a definition">,
>> > InGroup<IgnoredAttributes>;
>> >
>> > Modified: cfe/branches/release_33/lib/CodeGen/CodeGenModule.cpp
>> > URL:
>> http://llvm.org/viewvc/llvm-project/cfe/branches/release_33/lib/CodeGen/CodeGenModule.cpp?rev=182337&r1=182336&r2=182337&view=diff
>> >
>> ==============================================================================
>> > --- cfe/branches/release_33/lib/CodeGen/CodeGenModule.cpp (original)
>> > +++ cfe/branches/release_33/lib/CodeGen/CodeGenModule.cpp Mon May 20
>> 19:06:11 2013
>> > @@ -1900,7 +1900,13 @@ CodeGenModule::GetLLVMLinkageVarDefiniti
>> > return llvm::Function::DLLImportLinkage;
>> > else if (D->hasAttr<DLLExportAttr>())
>> > return llvm::Function::DLLExportLinkage;
>> > - else if (D->hasAttr<WeakAttr>()) {
>> > + else if (D->hasAttr<SelectAnyAttr>()) {
>> > + // selectany symbols are externally visible, so use weak instead of
>> > + // linkonce. MSVC optimizes away references to const selectany
>> globals, so
>> > + // all definitions should be the same and ODR linkage should be
>> used.
>> > + // http://msdn.microsoft.com/en-us/library/5tkz6s71.aspx
>> > + return llvm::GlobalVariable::WeakODRLinkage;
>> > + } else if (D->hasAttr<WeakAttr>()) {
>> > if (GV->isConstant())
>> > return llvm::GlobalVariable::WeakODRLinkage;
>> > else
>> >
>> > Modified: cfe/branches/release_33/lib/Sema/SemaDecl.cpp
>> > URL:
>> http://llvm.org/viewvc/llvm-project/cfe/branches/release_33/lib/Sema/SemaDecl.cpp?rev=182337&r1=182336&r2=182337&view=diff
>> >
>> ==============================================================================
>> > --- cfe/branches/release_33/lib/Sema/SemaDecl.cpp (original)
>> > +++ cfe/branches/release_33/lib/Sema/SemaDecl.cpp Mon May 20 19:06:11
>> 2013
>> > @@ -4638,6 +4638,15 @@ static void checkAttributesAfterMerging(
>> > ND.dropAttr<WeakRefAttr>();
>> > }
>> > }
>> > +
>> > + // 'selectany' only applies to externally visible varable
>> declarations.
>> > + // It does not apply to functions.
>> > + if (SelectAnyAttr *Attr = ND.getAttr<SelectAnyAttr>()) {
>> > + if (isa<FunctionDecl>(ND) || !ND.isExternallyVisible()) {
>> > + S.Diag(Attr->getLocation(),
>> diag::err_attribute_selectany_non_extern_data);
>> > + ND.dropAttr<SelectAnyAttr>();
>> > + }
>> > + }
>> > }
>> >
>> > /// Given that we are within the definition of the given function,
>> >
>> > Modified: cfe/branches/release_33/lib/Sema/SemaDeclAttr.cpp
>> > URL:
>> http://llvm.org/viewvc/llvm-project/cfe/branches/release_33/lib/Sema/SemaDeclAttr.cpp?rev=182337&r1=182336&r2=182337&view=diff
>> >
>> ==============================================================================
>> > --- cfe/branches/release_33/lib/Sema/SemaDeclAttr.cpp (original)
>> > +++ cfe/branches/release_33/lib/Sema/SemaDeclAttr.cpp Mon May 20
>> 19:06:11 2013
>> > @@ -4683,6 +4683,16 @@ static void handleForceInlineAttr(Sema &
>> > S.Diag(Attr.getLoc(), diag::warn_attribute_ignored) <<
>> Attr.getName();
>> > }
>> >
>> > +static void handleSelectAnyAttr(Sema &S, Decl *D, const AttributeList
>> &Attr) {
>> > + if (!checkMicrosoftExt(S, Attr))
>> > + return;
>> > + // Check linkage after possibly merging declaratinos. See
>> > + // checkAttributesAfterMerging().
>> > + D->addAttr(::new (S.Context)
>> > + SelectAnyAttr(Attr.getRange(), S.Context,
>> > + Attr.getAttributeSpellingListIndex()));
>> > +}
>> > +
>> >
>> //===----------------------------------------------------------------------===//
>> > // Top Level Sema Entry Points
>> >
>> //===----------------------------------------------------------------------===//
>> > @@ -4909,6 +4919,9 @@ static void ProcessInheritableDeclAttr(S
>> > case AttributeList::AT_ForceInline:
>> > handleForceInlineAttr(S, D, Attr);
>> > break;
>> > + case AttributeList::AT_SelectAny:
>> > + handleSelectAnyAttr(S, D, Attr);
>> > + break;
>> >
>> > // Thread safety attributes:
>> > case AttributeList::AT_GuardedVar:
>> >
>> > Modified: cfe/branches/release_33/test/CodeGen/ms-declspecs.c
>> > URL:
>> http://llvm.org/viewvc/llvm-project/cfe/branches/release_33/test/CodeGen/ms-declspecs.c?rev=182337&r1=182336&r2=182337&view=diff
>> >
>> ==============================================================================
>> > --- cfe/branches/release_33/test/CodeGen/ms-declspecs.c (original)
>> > +++ cfe/branches/release_33/test/CodeGen/ms-declspecs.c Mon May 20
>> 19:06:11 2013
>> > @@ -1,5 +1,10 @@
>> > // RUN: %clang_cc1 -triple i386-pc-win32 %s -emit-llvm
>> -fms-compatibility -o - | FileCheck %s
>> >
>> > +__declspec(selectany) int x1 = 1;
>> > +const __declspec(selectany) int x2 = 2;
>> > +// CHECK: @x1 = weak_odr global i32 1, align 4
>> > +// CHECK: @x2 = weak_odr constant i32 2, align 4
>> > +
>> > struct __declspec(align(16)) S {
>> > char x;
>> > };
>> >
>> >
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