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In -Wunneeded-internal-declaration, suppress the warning for variables which 

might have been used in constant expressions, rather than suppressing it for
variables which are const. The important thing here is that such variables
can have their values used without actually being marked as 'used'.

llvm-svn: 166896
This commit is contained in:
Richard Smith 2012-10-28 04:47:21 +00:00
parent 44938a738a
commit 27501e787c
2 changed files with 22 additions and 2 deletions
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9
clang/lib/Sema/SemaDecl.cpp
View File

@ -1205,10 +1205,17 @@ bool Sema::ShouldWarnIfUnusedFileScopedDecl(const DeclaratorDecl *D) const {
return false;
} else if (const VarDecl *VD = dyn_cast<VarDecl>(D)) {
if (!VD->isFileVarDecl() ||
VD->getType().isConstant(Context) ||
Context.DeclMustBeEmitted(VD))
return false;
// If a variable is usable in constant expressions and it's not odr-used,
// its value may still have been used. Conservatively suppress the warning
// in this case.
const VarDecl *VDWithInit = 0;
if (VD->isUsableInConstantExpressions(Context) &&
VD->getAnyInitializer(VDWithInit) && VDWithInit->checkInitIsICE())
return false;
if (VD->isStaticDataMember() &&
VD->getTemplateSpecializationKind() == TSK_ImplicitInstantiation)
return false;

15
clang/test/SemaCXX/warn-unused-filescoped.cpp
View File

@ -1,4 +1,5 @@
// RUN: %clang_cc1 -fsyntax-only -verify -Wunused -Wunused-member-function %s
// RUN: %clang_cc1 -fsyntax-only -verify -Wunused -Wunused-member-function -std=c++98 %s
// RUN: %clang_cc1 -fsyntax-only -verify -Wunused -Wunused-member-function -std=c++11 %s
static void f1(); // expected-warning{{unused}}
@ -87,3 +88,15 @@ namespace rdar8733476 {
foo();
}
}
namespace test5 {
static int n = 0;
static int &r = n;
int f(int &);
int k = f(r);
static const int m = n; // expected-warning {{not needed and will not be emitted}}
int x = sizeof(m);
static const double d = 0.0; // expected-warning {{not needed and will not be emitted}}
int y = sizeof(d);
}