[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/SemaTemplateInstantiateDecl.cpp lib/Serialization/ASTReaderDecl.cpp lib/Serialization/ASTWriterDecl.cpp test/Sema/warn-unused-function.c test/SemaCXX/warn-unused-filescoped.cpp
Argyrios Kyrtzidis
akyrtzi at gmail.com
Tue Apr 19 12:51:10 PDT 2011
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();
+ }
+}
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