[cfe-commits] r129794 - in /cfe/trunk: include/clang/AST/DeclBase.h include/clang/Basic/DiagnosticGroups.td include/clang/Basic/DiagnosticSemaKinds.td lib/AST/DeclBase.cpp lib/Sema/Sema.cpp lib/Sema/SemaExpr.cpp lib/Sema/SemaTemplateInstantiateDe
Nico Weber
thakis at chromium.org
Sat Apr 23 17:11:41 PDT 2011
On Sat, Apr 23, 2011 at 1:13 PM, Nico Weber <thakis at chromium.org> wrote:
> …and I can't just replace -Wno-unused-function with
> -Wno-unneeded-internal-declaration, because clang still warns about
>
> thakis-macbookpro:src thakis$ cat test.cc
> namespace {
> void f() {}
> }
I filed http://llvm.org/pr9786 for this. Other than that, I think
nothing else needs to be done here.
>
> while gcc doesn't. So -Wunused-function in gcc and clang are still
> different. Warnings about unused functions in the unnamed namespace
> should probably be moved to Wunneeded-internal-declaration.
>
> Nico
>
> On Sat, Apr 23, 2011 at 12:51 PM, Nico Weber <thakis at chromium.org> wrote:
>> Hi Argyrios,
>>
>> this breaks the chromium webkit build. The build now complains about
>> one unused function; clang didn't use to complain before. Maybe
>> -Wno-unused-function should imply -Wno-unneeded-internal-declaration?
>>
>> (It's not a big deal for us in practice – I'll add
>> -Wno-unneeded-internal-declaration to our build configuration. We're
>> building with -Wno-unused-function because the linker will drop unused
>> functions anyway and that warning was a little too noisy. In this
>> case, the new warning is also mostly noise – it's warning about a
>> static function defined in a header file that gets included in a cpp
>> file which uses that static function only if certain preprocessor
>> defines are set. I could include the header only under these
>> circumstances, but that seems like unnecessary busywork.)
>>
>> Just some random feedback; make of it what you will :-)
>>
>> Nico
>>
>> On Tue, Apr 19, 2011 at 12:51 PM, Argyrios Kyrtzidis <akyrtzi at gmail.com> wrote:
>>> Author: akirtzidis
>>> Date: Tue Apr 19 14:51:10 2011
>>> New Revision: 129794
>>>
>>> URL: http://llvm.org/viewvc/llvm-project?rev=129794&view=rev
>>> Log:
>>> We regard a function as 'unused' from the codegen perspective, so our warnings diverge from
>>> gcc's unused warnings which don't get emitted if the function is referenced even in an unevaluated context
>>> (e.g. in templates, sizeof, etc.). Also, saying that a function is 'unused' because it won't get codegen'ed
>>> is somewhat misleading.
>>>
>>> - Don't emit 'unused' warnings for functions that are referenced in any part of the user's code.
>>> - A warning that an internal function/variable won't get emitted is useful though, so introduce
>>> -Wunneeded-internal-declaration which will warn if a function/variable with internal linkage is not
>>> "needed" ('used' from the codegen perspective), e.g:
>>>
>>> static void foo() { }
>>>
>>> template <int>
>>> void bar() {
>>> foo();
>>> }
>>>
>>> test.cpp:1:13: warning: function 'foo' is not needed and will not be emitted
>>> static void foo() { }
>>> ^
>>>
>>> Addresses rdar://8733476.
>>>
>>> Modified:
>>> cfe/trunk/include/clang/AST/DeclBase.h
>>> cfe/trunk/include/clang/Basic/DiagnosticGroups.td
>>> cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
>>> cfe/trunk/lib/AST/DeclBase.cpp
>>> cfe/trunk/lib/Sema/Sema.cpp
>>> cfe/trunk/lib/Sema/SemaExpr.cpp
>>> cfe/trunk/lib/Sema/SemaTemplateInstantiateDecl.cpp
>>> cfe/trunk/lib/Serialization/ASTReaderDecl.cpp
>>> cfe/trunk/lib/Serialization/ASTWriterDecl.cpp
>>> cfe/trunk/test/Sema/warn-unused-function.c
>>> cfe/trunk/test/SemaCXX/warn-unused-filescoped.cpp
>>>
>>> Modified: cfe/trunk/include/clang/AST/DeclBase.h
>>> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/AST/DeclBase.h?rev=129794&r1=129793&r2=129794&view=diff
>>> ==============================================================================
>>> --- cfe/trunk/include/clang/AST/DeclBase.h (original)
>>> +++ cfe/trunk/include/clang/AST/DeclBase.h Tue Apr 19 14:51:10 2011
>>> @@ -227,6 +227,12 @@
>>> /// required.
>>> unsigned Used : 1;
>>>
>>> + /// \brief Whether this declaration was "referenced".
>>> + /// The difference with 'Used' is whether the reference appears in a
>>> + /// evaluated context or not, e.g. functions used in uninstantiated templates
>>> + /// are regarded as "referenced" but not "used".
>>> + unsigned Referenced : 1;
>>> +
>>> protected:
>>> /// Access - Used by C++ decls for the access specifier.
>>> // NOTE: VC++ treats enums as signed, avoid using the AccessSpecifier enum
>>> @@ -261,7 +267,7 @@
>>> Decl(Kind DK, DeclContext *DC, SourceLocation L)
>>> : NextDeclInContext(0), DeclCtx(DC),
>>> Loc(L), DeclKind(DK), InvalidDecl(0),
>>> - HasAttrs(false), Implicit(false), Used(false),
>>> + HasAttrs(false), Implicit(false), Used(false), Referenced(false),
>>> Access(AS_none), PCHLevel(0), ChangedAfterLoad(false),
>>> IdentifierNamespace(getIdentifierNamespaceForKind(DK)),
>>> HasCachedLinkage(0)
>>> @@ -271,7 +277,7 @@
>>>
>>> Decl(Kind DK, EmptyShell Empty)
>>> : NextDeclInContext(0), DeclKind(DK), InvalidDecl(0),
>>> - HasAttrs(false), Implicit(false), Used(false),
>>> + HasAttrs(false), Implicit(false), Used(false), Referenced(false),
>>> Access(AS_none), PCHLevel(0), ChangedAfterLoad(false),
>>> IdentifierNamespace(getIdentifierNamespaceForKind(DK)),
>>> HasCachedLinkage(0)
>>> @@ -408,6 +414,11 @@
>>>
>>> void setUsed(bool U = true) { Used = U; }
>>>
>>> + /// \brief Whether this declaration was referenced.
>>> + bool isReferenced() const;
>>> +
>>> + void setReferenced(bool R = true) { Referenced = R; }
>>> +
>>> /// \brief Determine the availability of the given declaration.
>>> ///
>>> /// This routine will determine the most restrictive availability of
>>>
>>> Modified: cfe/trunk/include/clang/Basic/DiagnosticGroups.td
>>> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/DiagnosticGroups.td?rev=129794&r1=129793&r2=129794&view=diff
>>> ==============================================================================
>>> --- cfe/trunk/include/clang/Basic/DiagnosticGroups.td (original)
>>> +++ cfe/trunk/include/clang/Basic/DiagnosticGroups.td Tue Apr 19 14:51:10 2011
>>> @@ -154,6 +154,8 @@
>>> def UnusedParameter : DiagGroup<"unused-parameter">;
>>> def UnusedValue : DiagGroup<"unused-value">;
>>> def UnusedVariable : DiagGroup<"unused-variable">;
>>> +def UnneededInternalDecl : DiagGroup<"unneeded-internal-declaration">;
>>> +def UnneededMemberFunction : DiagGroup<"unneeded-member-function">;
>>> def UsedButMarkedUnused : DiagGroup<"used-but-marked-unused">;
>>> def ReadOnlySetterAttrs : DiagGroup<"readonly-setter-attrs">;
>>> def Reorder : DiagGroup<"reorder">;
>>> @@ -198,11 +200,16 @@
>>> BoolConversions]>,
>>> DiagCategory<"Value Conversion Issue">;
>>>
>>> +def Unneeded : DiagGroup<"unneeded",
>>> + [UnneededInternalDecl
>>> + //,UnneededMemberFunction (clean-up llvm before enabling)
>>> + ]>;
>>> +
>>> def Unused : DiagGroup<"unused",
>>> [UnusedArgument, UnusedFunction, UnusedLabel,
>>> // UnusedParameter, (matches GCC's behavior)
>>> // UnusedMemberFunction, (clean-up llvm before enabling)
>>> - UnusedValue, UnusedVariable]>,
>>> + UnusedValue, UnusedVariable, Unneeded]>,
>>> DiagCategory<"Unused Entity Issue">;
>>>
>>> // Format settings.
>>>
>>> Modified: cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
>>> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td?rev=129794&r1=129793&r2=129794&view=diff
>>> ==============================================================================
>>> --- cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td (original)
>>> +++ cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td Tue Apr 19 14:51:10 2011
>>> @@ -116,6 +116,12 @@
>>> InGroup<UnusedMemberFunction>, DefaultIgnore;
>>> def warn_used_but_marked_unused: Warning<"%0 was marked unused but was used">,
>>> InGroup<UsedButMarkedUnused>, DefaultIgnore;
>>> +def warn_unneeded_internal_decl : Warning<
>>> + "%select{function|variable}0 %1 is not needed and will not be emitted">,
>>> + InGroup<UnneededInternalDecl>, DefaultIgnore;
>>> +def warn_unneeded_member_function : Warning<
>>> + "member function %0 is not needed and will not be emitted">,
>>> + InGroup<UnneededMemberFunction>, DefaultIgnore;
>>>
>>> def warn_parameter_size: Warning<
>>> "%0 is a large (%1 bytes) pass-by-value argument; "
>>>
>>> Modified: cfe/trunk/lib/AST/DeclBase.cpp
>>> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/AST/DeclBase.cpp?rev=129794&r1=129793&r2=129794&view=diff
>>> ==============================================================================
>>> --- cfe/trunk/lib/AST/DeclBase.cpp (original)
>>> +++ cfe/trunk/lib/AST/DeclBase.cpp Tue Apr 19 14:51:10 2011
>>> @@ -242,6 +242,18 @@
>>> return false;
>>> }
>>>
>>> +bool Decl::isReferenced() const {
>>> + if (Referenced)
>>> + return true;
>>> +
>>> + // Check redeclarations.
>>> + for (redecl_iterator I = redecls_begin(), E = redecls_end(); I != E; ++I)
>>> + if (I->Referenced)
>>> + return true;
>>> +
>>> + return false;
>>> +}
>>> +
>>> /// \brief Determine the availability of the given declaration based on
>>> /// the target platform.
>>> ///
>>>
>>> Modified: cfe/trunk/lib/Sema/Sema.cpp
>>> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/Sema.cpp?rev=129794&r1=129793&r2=129794&view=diff
>>> ==============================================================================
>>> --- cfe/trunk/lib/Sema/Sema.cpp (original)
>>> +++ cfe/trunk/lib/Sema/Sema.cpp Tue Apr 19 14:51:10 2011
>>> @@ -473,16 +473,30 @@
>>> DiagD = FD;
>>> if (DiagD->isDeleted())
>>> continue; // Deleted functions are supposed to be unused.
>>> - Diag(DiagD->getLocation(),
>>> - isa<CXXMethodDecl>(DiagD) ? diag::warn_unused_member_function
>>> - : diag::warn_unused_function)
>>> - << DiagD->getDeclName();
>>> + if (DiagD->isReferenced()) {
>>> + if (isa<CXXMethodDecl>(DiagD))
>>> + Diag(DiagD->getLocation(), diag::warn_unneeded_member_function)
>>> + << DiagD->getDeclName();
>>> + else
>>> + Diag(DiagD->getLocation(), diag::warn_unneeded_internal_decl)
>>> + << /*function*/0 << DiagD->getDeclName();
>>> + } else {
>>> + Diag(DiagD->getLocation(),
>>> + isa<CXXMethodDecl>(DiagD) ? diag::warn_unused_member_function
>>> + : diag::warn_unused_function)
>>> + << DiagD->getDeclName();
>>> + }
>>> } else {
>>> const VarDecl *DiagD = cast<VarDecl>(*I)->getDefinition();
>>> if (!DiagD)
>>> DiagD = cast<VarDecl>(*I);
>>> - Diag(DiagD->getLocation(), diag::warn_unused_variable)
>>> - << DiagD->getDeclName();
>>> + if (DiagD->isReferenced()) {
>>> + Diag(DiagD->getLocation(), diag::warn_unneeded_internal_decl)
>>> + << /*variable*/1 << DiagD->getDeclName();
>>> + } else {
>>> + Diag(DiagD->getLocation(), diag::warn_unused_variable)
>>> + << DiagD->getDeclName();
>>> + }
>>> }
>>> }
>>>
>>>
>>> Modified: cfe/trunk/lib/Sema/SemaExpr.cpp
>>> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaExpr.cpp?rev=129794&r1=129793&r2=129794&view=diff
>>> ==============================================================================
>>> --- cfe/trunk/lib/Sema/SemaExpr.cpp (original)
>>> +++ cfe/trunk/lib/Sema/SemaExpr.cpp Tue Apr 19 14:51:10 2011
>>> @@ -9885,6 +9885,8 @@
>>> void Sema::MarkDeclarationReferenced(SourceLocation Loc, Decl *D) {
>>> assert(D && "No declaration?");
>>>
>>> + D->setReferenced();
>>> +
>>> if (D->isUsed(false))
>>> return;
>>>
>>>
>>> Modified: cfe/trunk/lib/Sema/SemaTemplateInstantiateDecl.cpp
>>> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaTemplateInstantiateDecl.cpp?rev=129794&r1=129793&r2=129794&view=diff
>>> ==============================================================================
>>> --- cfe/trunk/lib/Sema/SemaTemplateInstantiateDecl.cpp (original)
>>> +++ cfe/trunk/lib/Sema/SemaTemplateInstantiateDecl.cpp Tue Apr 19 14:51:10 2011
>>> @@ -298,8 +298,10 @@
>>>
>>> Var->setAccess(D->getAccess());
>>>
>>> - if (!D->isStaticDataMember())
>>> + if (!D->isStaticDataMember()) {
>>> Var->setUsed(D->isUsed(false));
>>> + Var->setReferenced(D->isReferenced());
>>> + }
>>>
>>> // FIXME: In theory, we could have a previous declaration for variables that
>>> // are not static data members.
>>>
>>> Modified: cfe/trunk/lib/Serialization/ASTReaderDecl.cpp
>>> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Serialization/ASTReaderDecl.cpp?rev=129794&r1=129793&r2=129794&view=diff
>>> ==============================================================================
>>> --- cfe/trunk/lib/Serialization/ASTReaderDecl.cpp (original)
>>> +++ cfe/trunk/lib/Serialization/ASTReaderDecl.cpp Tue Apr 19 14:51:10 2011
>>> @@ -214,6 +214,7 @@
>>> }
>>> D->setImplicit(Record[Idx++]);
>>> D->setUsed(Record[Idx++]);
>>> + D->setReferenced(Record[Idx++]);
>>> D->setAccess((AccessSpecifier)Record[Idx++]);
>>> D->setPCHLevel(Record[Idx++] + (F.Type <= ASTReader::PCH));
>>> }
>>>
>>> Modified: cfe/trunk/lib/Serialization/ASTWriterDecl.cpp
>>> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Serialization/ASTWriterDecl.cpp?rev=129794&r1=129793&r2=129794&view=diff
>>> ==============================================================================
>>> --- cfe/trunk/lib/Serialization/ASTWriterDecl.cpp (original)
>>> +++ cfe/trunk/lib/Serialization/ASTWriterDecl.cpp Tue Apr 19 14:51:10 2011
>>> @@ -141,6 +141,7 @@
>>> Writer.WriteAttributes(D->getAttrs(), Record);
>>> Record.push_back(D->isImplicit());
>>> Record.push_back(D->isUsed(false));
>>> + Record.push_back(D->isReferenced());
>>> Record.push_back(D->getAccess());
>>> Record.push_back(D->getPCHLevel());
>>> }
>>> @@ -1133,6 +1134,7 @@
>>> Abv->Add(BitCodeAbbrevOp(0)); // HasAttrs
>>> Abv->Add(BitCodeAbbrevOp(0)); // isImplicit
>>> Abv->Add(BitCodeAbbrevOp(0)); // isUsed
>>> + Abv->Add(BitCodeAbbrevOp(0)); // isReferenced
>>> Abv->Add(BitCodeAbbrevOp(AS_none)); // C++ AccessSpecifier
>>> Abv->Add(BitCodeAbbrevOp(0)); // PCH level
>>>
>>>
>>> Modified: cfe/trunk/test/Sema/warn-unused-function.c
>>> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Sema/warn-unused-function.c?rev=129794&r1=129793&r2=129794&view=diff
>>> ==============================================================================
>>> --- cfe/trunk/test/Sema/warn-unused-function.c (original)
>>> +++ cfe/trunk/test/Sema/warn-unused-function.c Tue Apr 19 14:51:10 2011
>>> @@ -1,4 +1,4 @@
>>> -// RUN: %clang_cc1 -fsyntax-only -Wunused-function -verify %s
>>> +// RUN: %clang_cc1 -fsyntax-only -Wunused-function -Wunneeded-internal-declaration -verify %s
>>> // RUN: %clang_cc1 -fsyntax-only -verify -Wunused %s
>>> // RUN: %clang_cc1 -fsyntax-only -verify -Wall %s
>>>
>>> @@ -6,7 +6,7 @@
>>> static void f2() {}
>>> static void f1() {f2();} // expected-warning{{unused}}
>>>
>>> -static int f0() { return 17; } // expected-warning{{unused}}
>>> +static int f0() { return 17; } // expected-warning{{not needed and will not be emitted}}
>>> int x = sizeof(f0());
>>>
>>> static void f3();
>>> @@ -46,7 +46,7 @@
>>> static void f12(void);
>>>
>>> // PR7923
>>> -static void unused(void) { unused(); } // expected-warning{{unused}}
>>> +static void unused(void) { unused(); } // expected-warning{{not needed and will not be emitted}}
>>>
>>> // rdar://8728293
>>> static void cleanupMalloc(char * const * const allocation) { }
>>>
>>> Modified: cfe/trunk/test/SemaCXX/warn-unused-filescoped.cpp
>>> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/warn-unused-filescoped.cpp?rev=129794&r1=129793&r2=129794&view=diff
>>> ==============================================================================
>>> --- cfe/trunk/test/SemaCXX/warn-unused-filescoped.cpp (original)
>>> +++ cfe/trunk/test/SemaCXX/warn-unused-filescoped.cpp Tue Apr 19 14:51:10 2011
>>> @@ -78,3 +78,12 @@
>>> void test(A a); // expected-warning {{unused function}}
>>> extern "C" void test4(A a);
>>> }
>>> +
>>> +namespace rdar8733476 {
>>> + static void foo() { } // expected-warning {{not needed and will not be emitted}}
>>> +
>>> + template <int>
>>> + void bar() {
>>> + foo();
>>> + }
>>> +}
>>>
>>>
>>> _______________________________________________
>>> cfe-commits mailing list
>>> cfe-commits at cs.uiuc.edu
>>> http://lists.cs.uiuc.edu/mailman/listinfo/cfe-commits
>>>
>>
>
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