r363749 - Suggestions to fix -Wmissing-{prototypes, variable-declarations}
Aaron Puchert via cfe-commits
cfe-commits at lists.llvm.org
Tue Jun 18 15:57:08 PDT 2019
Author: aaronpuchert
Date: Tue Jun 18 15:57:08 2019
New Revision: 363749
URL: http://llvm.org/viewvc/llvm-project?rev=363749&view=rev
Log:
Suggestions to fix -Wmissing-{prototypes,variable-declarations}
Summary:
I've found that most often the proper way to fix this warning is to add
`static`, because if the code otherwise compiles and links, the function
or variable is apparently not needed outside of the TU.
We can't provide a fix-it hint for variable declarations, because
multiple VarDecls can share the same type, and if we put static in front
of that, we affect all declared variables, some of which might have
previous declarations.
We also provide no fix-it hint for the rare case of an `extern` function
definition, because that would require removing `extern` and I have no
idea how to get the source location of the storage class specifier from
a FunctionDecl. I believe this information is only available earlier in
the AST construction from DeclSpec::getStorageClassSpecLoc(), but we
don't have that here.
Reviewed By: aaron.ballman
Differential Revision: https://reviews.llvm.org/D59402
Modified:
cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
cfe/trunk/lib/Sema/SemaDecl.cpp
cfe/trunk/test/Sema/warn-missing-prototypes.c
cfe/trunk/test/Sema/warn-missing-variable-declarations.c
cfe/trunk/test/SemaCXX/warn-missing-prototypes.cpp
cfe/trunk/test/SemaCXX/warn-missing-variable-declarations.cpp
cfe/trunk/test/SemaOpenCL/warn-missing-prototypes.cl
Modified: cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td?rev=363749&r1=363748&r2=363749&view=diff
==============================================================================
--- cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td (original)
+++ cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td Tue Jun 18 15:57:08 2019
@@ -4681,6 +4681,9 @@ def warn_strict_prototypes : Warning<
def warn_missing_variable_declarations : Warning<
"no previous extern declaration for non-static variable %0">,
InGroup<DiagGroup<"missing-variable-declarations">>, DefaultIgnore;
+def note_static_for_internal_linkage : Note<
+ "declare 'static' if the %select{variable|function}0 is not intended to be "
+ "used outside of this translation unit">;
def err_static_data_member_reinitialization :
Error<"static data member %0 already has an initializer">;
def err_redefinition : Error<"redefinition of %0">;
Modified: cfe/trunk/lib/Sema/SemaDecl.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaDecl.cpp?rev=363749&r1=363748&r2=363749&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaDecl.cpp (original)
+++ cfe/trunk/lib/Sema/SemaDecl.cpp Tue Jun 18 15:57:08 2019
@@ -11899,8 +11899,11 @@ void Sema::CheckCompleteVariableDeclarat
while (prev && prev->isThisDeclarationADefinition())
prev = prev->getPreviousDecl();
- if (!prev)
+ if (!prev) {
Diag(var->getLocation(), diag::warn_missing_variable_declarations) << var;
+ Diag(var->getTypeSpecStartLoc(), diag::note_static_for_internal_linkage)
+ << /* variable */ 0;
+ }
}
// Cache the result of checking for constant initialization.
@@ -13364,6 +13367,13 @@ Decl *Sema::ActOnFinishFunctionBody(Decl
? FixItHint::CreateInsertion(FTL.getRParenLoc(), "void")
: FixItHint{});
}
+ } else {
+ Diag(FD->getTypeSpecStartLoc(), diag::note_static_for_internal_linkage)
+ << /* function */ 1
+ << (FD->getStorageClass() == SC_None
+ ? FixItHint::CreateInsertion(FD->getTypeSpecStartLoc(),
+ "static ")
+ : FixItHint{});
}
// GNU warning -Wstrict-prototypes
Modified: cfe/trunk/test/Sema/warn-missing-prototypes.c
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Sema/warn-missing-prototypes.c?rev=363749&r1=363748&r2=363749&view=diff
==============================================================================
--- cfe/trunk/test/Sema/warn-missing-prototypes.c (original)
+++ cfe/trunk/test/Sema/warn-missing-prototypes.c Tue Jun 18 15:57:08 2019
@@ -9,11 +9,17 @@ int f(int x) { return x; } // expected-w
static int g(int x) { return x; }
int h(int x) { return x; } // expected-warning{{no previous prototype for function 'h'}}
+// expected-note at -1{{declare 'static' if the function is not intended to be used outside of this translation unit}}
+// CHECK: fix-it:"{{.*}}":{[[@LINE-2]]:1-[[@LINE-2]]:1}:"static "
static int g2();
int g2(int x) { return x; }
+extern int g3(int x) { return x; } // expected-warning{{no previous prototype for function 'g3'}}
+// expected-note at -1{{declare 'static' if the function is not intended to be used outside of this translation unit}}
+// CHECK-NOT: fix-it:"{{.*}}":{[[@LINE-2]]:{{.*}}-[[@LINE-2]]:{{.*}}}:"{{.*}}"
+
void test(void);
int h3(); // expected-note{{this declaration is not a prototype; add parameter declarations to make it one}}
@@ -28,6 +34,7 @@ void test(void) {
}
int h2(int x) { return x; } // expected-warning{{no previous prototype for function 'h2'}}
+// expected-note at -1{{declare 'static' if the function is not intended to be used outside of this translation unit}}
int h3(int x) { return x; } // expected-warning{{no previous prototype for function 'h3'}}
int h4(int x) { return x; }
Modified: cfe/trunk/test/Sema/warn-missing-variable-declarations.c
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Sema/warn-missing-variable-declarations.c?rev=363749&r1=363748&r2=363749&view=diff
==============================================================================
--- cfe/trunk/test/Sema/warn-missing-variable-declarations.c (original)
+++ cfe/trunk/test/Sema/warn-missing-variable-declarations.c Tue Jun 18 15:57:08 2019
@@ -1,16 +1,19 @@
// RUN: %clang_cc1 -Wmissing-variable-declarations -fsyntax-only -verify %s
int vbad1; // expected-warning{{no previous extern declaration for non-static variable 'vbad1'}}
+// expected-note at -1{{declare 'static' if the variable is not intended to be used outside of this translation unit}}
int vbad2;
int vbad2 = 10; // expected-warning{{no previous extern declaration for non-static variable 'vbad2'}}
+// expected-note at -1{{declare 'static' if the variable is not intended to be used outside of this translation unit}}
-struct {
+struct { // expected-note{{declare 'static' if the variable is not intended to be used outside of this translation unit}}
int mgood1;
} vbad3; // expected-warning{{no previous extern declaration for non-static variable 'vbad3'}}
int vbad4;
int vbad4 = 10; // expected-warning{{no previous extern declaration for non-static variable 'vbad4'}}
+// expected-note at -1{{declare 'static' if the variable is not intended to be used outside of this translation unit}}
extern int vbad4;
extern int vgood1;
Modified: cfe/trunk/test/SemaCXX/warn-missing-prototypes.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/warn-missing-prototypes.cpp?rev=363749&r1=363748&r2=363749&view=diff
==============================================================================
--- cfe/trunk/test/SemaCXX/warn-missing-prototypes.cpp (original)
+++ cfe/trunk/test/SemaCXX/warn-missing-prototypes.cpp Tue Jun 18 15:57:08 2019
@@ -1,9 +1,13 @@
// RUN: %clang_cc1 -fsyntax-only -verify -Wmissing-prototypes -std=c++11 %s
+// RUN: %clang_cc1 -fsyntax-only -Wmissing-prototypes -fdiagnostics-parseable-fixits %s 2>&1 | FileCheck %s
void f() { } // expected-warning {{no previous prototype for function 'f'}}
+// expected-note at -1{{declare 'static' if the function is not intended to be used outside of this translation unit}}
+// CHECK: fix-it:"{{.*}}":{[[@LINE-2]]:1-[[@LINE-2]]:1}:"static "
namespace NS {
void f() { } // expected-warning {{no previous prototype for function 'f'}}
+ // expected-note at -1{{declare 'static' if the function is not intended to be used outside of this translation unit}}
}
namespace {
@@ -32,3 +36,7 @@ class I {
// Don't warn on explicitly deleted functions.
void j() = delete;
+
+extern void k() {} // expected-warning {{no previous prototype for function 'k'}}
+// expected-note at -1{{declare 'static' if the function is not intended to be used outside of this translation unit}}
+// CHECK-NOT: fix-it:"{{.*}}":{[[@LINE-2]]:{{.*}}-[[@LINE-2]]:{{.*}}}:"{{.*}}"
Modified: cfe/trunk/test/SemaCXX/warn-missing-variable-declarations.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/warn-missing-variable-declarations.cpp?rev=363749&r1=363748&r2=363749&view=diff
==============================================================================
--- cfe/trunk/test/SemaCXX/warn-missing-variable-declarations.cpp (original)
+++ cfe/trunk/test/SemaCXX/warn-missing-variable-declarations.cpp Tue Jun 18 15:57:08 2019
@@ -1,11 +1,15 @@
-// RUN: %clang -Wmissing-variable-declarations -fsyntax-only -Xclang -verify -std=c++17 %s
+// RUN: %clang_cc1 -fsyntax-only -verify -Wmissing-variable-declarations -std=c++17 %s
// Variable declarations that should trigger a warning.
int vbad1; // expected-warning{{no previous extern declaration for non-static variable 'vbad1'}}
+// expected-note at -1{{declare 'static' if the variable is not intended to be used outside of this translation unit}}
+
int vbad2 = 10; // expected-warning{{no previous extern declaration for non-static variable 'vbad2'}}
+// expected-note at -1{{declare 'static' if the variable is not intended to be used outside of this translation unit}}
namespace x {
int vbad3; // expected-warning{{no previous extern declaration for non-static variable 'vbad3'}}
+ // expected-note at -1{{declare 'static' if the variable is not intended to be used outside of this translation unit}}
}
// Variable declarations that should not trigger a warning.
@@ -58,7 +62,9 @@ const int const_var = 0;
constexpr int constexpr_var = 0;
inline constexpr int inline_constexpr_var = 0;
extern const int extern_const_var = 0; // expected-warning {{no previous extern declaration}}
+// expected-note at -1{{declare 'static' if the variable is not intended to be used outside of this translation unit}}
extern constexpr int extern_constexpr_var = 0; // expected-warning {{no previous extern declaration}}
+// expected-note at -1{{declare 'static' if the variable is not intended to be used outside of this translation unit}}
template<typename> int var_template = 0;
template<typename> constexpr int const_var_template = 0;
@@ -69,7 +75,9 @@ int use_var_template() { return var_temp
template int var_template<int[3]>;
extern template int var_template<int[4]>;
template<> int var_template<int[5]>; // expected-warning {{no previous extern declaration}}
+// expected-note at -1{{declare 'static' if the variable is not intended to be used outside of this translation unit}}
// FIXME: We give this specialization internal linkage rather than inheriting
// the linkage from the template! We should not warn here.
template<> int static_var_template<int[5]>; // expected-warning {{no previous extern declaration}}
+// expected-note at -1{{declare 'static' if the variable is not intended to be used outside of this translation unit}}
Modified: cfe/trunk/test/SemaOpenCL/warn-missing-prototypes.cl
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaOpenCL/warn-missing-prototypes.cl?rev=363749&r1=363748&r2=363749&view=diff
==============================================================================
--- cfe/trunk/test/SemaOpenCL/warn-missing-prototypes.cl (original)
+++ cfe/trunk/test/SemaOpenCL/warn-missing-prototypes.cl Tue Jun 18 15:57:08 2019
@@ -1,6 +1,7 @@
// RUN: %clang_cc1 -fsyntax-only -verify -Wmissing-prototypes %s
void f() { } // expected-warning {{no previous prototype for function 'f'}}
+// expected-note at -1{{declare 'static' if the function is not intended to be used outside of this translation unit}}
// Don't warn about kernel functions.
kernel void g() { }
More information about the cfe-commits
mailing list