aaronpuchert created this revision.
aaronpuchert added reviewers: bkramer, efriedma, rsmith.
Herald added subscribers: cfe-commits, jdoerfert.
Herald added a project: clang.
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.
There is no fix-it for the rare case of an "extern 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 VarDecl. I believe
this information is only available earlier in the AST construction from
DeclSpec::getStorageClassSpecLoc(), but we don't have that here.
Repository:
rC Clang
https://reviews.llvm.org/D59402
Files:
lib/Sema/SemaDecl.cpp
test/Sema/warn-missing-prototypes.c
test/Sema/warn-missing-variable-declarations.c
test/SemaCXX/warn-missing-variable-declarations.cpp
Index: test/SemaCXX/warn-missing-variable-declarations.cpp
===================================================================
--- test/SemaCXX/warn-missing-variable-declarations.cpp
+++ test/SemaCXX/warn-missing-variable-declarations.cpp
@@ -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
+// RUN: %clang_cc1 -fsyntax-only -Wmissing-variable-declarations -fdiagnostics-parseable-fixits -std=c++17 %s 2>&1 | FileCheck %s
// Variable declarations that should trigger a warning.
int vbad1; // expected-warning{{no previous extern declaration for non-static variable 'vbad1'}}
+// CHECK: fix-it:"{{.*}}":{[[@LINE-1]]:1-[[@LINE-1]]:1}:"static "
int vbad2 = 10; // expected-warning{{no previous extern declaration for non-static variable 'vbad2'}}
+// CHECK: fix-it:"{{.*}}":{[[@LINE-1]]:1-[[@LINE-1]]:1}:"static "
namespace x {
int vbad3; // expected-warning{{no previous extern declaration for non-static variable 'vbad3'}}
+ // CHECK: fix-it:"{{.*}}":{[[@LINE-1]]:3-[[@LINE-1]]:3}:"static "
}
// Variable declarations that should not trigger a warning.
@@ -58,7 +62,9 @@
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}}
+// CHECK-NOT: fix-it:"{{.*}}":{[[@LINE-1]]{{.*}}}:"{{.*}}"
extern constexpr int extern_constexpr_var = 0; // expected-warning {{no previous extern declaration}}
+// CHECK-NOT: fix-it:"{{.*}}":{[[@LINE-1]]{{.*}}}:"{{.*}}"
template<typename> int var_template = 0;
template<typename> constexpr int const_var_template = 0;
Index: test/Sema/warn-missing-variable-declarations.c
===================================================================
--- test/Sema/warn-missing-variable-declarations.c
+++ test/Sema/warn-missing-variable-declarations.c
@@ -1,6 +1,8 @@
// RUN: %clang_cc1 -Wmissing-variable-declarations -fsyntax-only -verify %s
+// RUN: %clang_cc1 -fsyntax-only -Wmissing-variable-declarations -fdiagnostics-parseable-fixits %s 2>&1 | FileCheck %s
int vbad1; // expected-warning{{no previous extern declaration for non-static variable 'vbad1'}}
+// CHECK: fix-it:"{{.*}}":{[[@LINE-1]]:1-[[@LINE-1]]:1}:"static "
int vbad2;
int vbad2 = 10; // expected-warning{{no previous extern declaration for non-static variable 'vbad2'}}
@@ -8,6 +10,7 @@
struct {
int mgood1;
} vbad3; // expected-warning{{no previous extern declaration for non-static variable 'vbad3'}}
+// CHECK: fix-it:"{{.*}}":{[[@LINE-3]]:1-[[@LINE-3]]:1}:"static "
int vbad4;
int vbad4 = 10; // expected-warning{{no previous extern declaration for non-static variable 'vbad4'}}
Index: test/Sema/warn-missing-prototypes.c
===================================================================
--- test/Sema/warn-missing-prototypes.c
+++ test/Sema/warn-missing-prototypes.c
@@ -4,6 +4,7 @@
int f();
int f(int x) { return x; } // expected-warning{{no previous prototype for function 'f'}}
+// CHECK: fix-it:"{{.*}}":{[[@LINE-1]]:1-[[@LINE-1]]:1}:"static "
static int g(int x) { return x; }
@@ -13,6 +14,9 @@
int g2(int x) { return x; }
+extern int g3(int x) { return x; } // expected-warning{{no previous prototype for function 'g3'}}
+// CHECK-NOT: fix-it:"{{.*}}":{[[@LINE-1]]{{.*}}}:"{{.*}}"
+
void test(void);
int h3();
@@ -40,4 +44,4 @@
void not_a_prototype_test(); // expected-note{{this declaration is not a prototype; add 'void' to make it a prototype for a zero-parameter function}}
void not_a_prototype_test() { } // expected-warning{{no previous prototype for function 'not_a_prototype_test'}}
-// CHECK: fix-it:"{{.*}}":{40:27-40:27}:"void"
+// CHECK: fix-it:"{{.*}}":{[[@LINE-3]]:27-[[@LINE-3]]:27}:"void"
Index: lib/Sema/SemaDecl.cpp
===================================================================
--- lib/Sema/SemaDecl.cpp
+++ lib/Sema/SemaDecl.cpp
@@ -11805,7 +11805,11 @@
prev = prev->getPreviousDecl();
if (!prev)
- Diag(var->getLocation(), diag::warn_missing_variable_declarations) << var;
+ Diag(var->getLocation(), diag::warn_missing_variable_declarations)
+ << var
+ << ((var->getStorageClass() != SC_Extern)
+ ? FixItHint::CreateInsertion(var->getBeginLoc(), "static ")
+ : FixItHint{});
}
// Cache the result of checking for constant initialization.
@@ -13209,7 +13213,11 @@
// global functions that fail to be declared in header files.
const FunctionDecl *PossibleZeroParamPrototype = nullptr;
if (ShouldWarnAboutMissingPrototype(FD, PossibleZeroParamPrototype)) {
- Diag(FD->getLocation(), diag::warn_missing_prototype) << FD;
+ Diag(FD->getLocation(), diag::warn_missing_prototype)
+ << FD
+ << ((FD->getStorageClass() != SC_Extern)
+ ? FixItHint::CreateInsertion(FD->getBeginLoc(), "static ")
+ : FixItHint{});
if (PossibleZeroParamPrototype) {
// We found a declaration that is not a prototype,
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