[OB PATCH] Avoid testcase build failures with -Wunused-value

[OB PATCH] Avoid testcase build failures with -Wunused-value

[Gary Benson]

A number of testcases fail to build with -Wunused-value enabled.
This commit adds dummy values to avoid this.

gdb/testsuite/ChangeLog:

	* gdb.cp/namespace.cc: Avoid build failure with -Wunused-value.
	* gdb.cp/nsimport.cc: Likewise.
	* gdb.cp/nsnested.cc: Likewise.
	* gdb.cp/nsnoimports.cc: Likewise.
	* gdb.cp/nsusing.cc: Likewise.
	* gdb.cp/smartp.cc: Likewise.
	* gdb.python/py-pp-integral.c: Likewise.
	* gdb.python/py-pp-re-notag.c: Likewise.
---
 gdb/testsuite/ChangeLog                   | 11 +++++++++++
 gdb/testsuite/gdb.cp/namespace.cc         | 22 +++++++++++-----------
 gdb/testsuite/gdb.cp/nsimport.cc          |  6 +++---
 gdb/testsuite/gdb.cp/nsnested.cc          |  2 +-
 gdb/testsuite/gdb.cp/nsnoimports.cc       | 12 ++++++------
 gdb/testsuite/gdb.cp/nsusing.cc           | 12 ++++++------
 gdb/testsuite/gdb.cp/smartp.cc            |  8 ++++----
 gdb/testsuite/gdb.python/py-pp-integral.c |  4 ++--
 gdb/testsuite/gdb.python/py-pp-re-notag.c |  4 ++--
 9 files changed, 46 insertions(+), 35 deletions(-)

diff --git a/gdb/testsuite/gdb.cp/namespace.cc b/gdb/testsuite/gdb.cp/namespace.cc
index f918b63..1ff3426 100644
--- a/gdb/testsuite/gdb.cp/namespace.cc
+++ b/gdb/testsuite/gdb.cp/namespace.cc
@@ -150,22 +150,22 @@ namespace C
       // plan to have GDB try to print out, just to make sure that the
       // compiler and I agree which ones should be legal!  It's easy
       // to screw up when testing the boundaries of namespace stuff.
-      c;
+      int unused1 = c;
       //cc;
-      C::cc;
-      cd;
+      int unused2 = C::cc;
+      int unused3 = cd;
       //C::D::cd;
-      E::cde;
-      shadow;
+      int unused4 = E::cde;
+      int unused5 = shadow;
       //E::ce;
-      cX;
-      F::cXf;
-      F::cXfX;
-      X;
-      G::Xg;
+      int unused6 = cX;
+      int unused7 = F::cXf;
+      int unused8 = F::cXfX;
+      int unused9 = X;
+      int unusedA = G::Xg;
       //cXOtherFile;
       //XOtherFile;
-      G::XgX;
+      int unusedB = G::XgX;
 
       return;
     }
diff --git a/gdb/testsuite/gdb.cp/nsimport.cc b/gdb/testsuite/gdb.cp/nsimport.cc
index 6b180d6..5fc57b0 100644
--- a/gdb/testsuite/gdb.cp/nsimport.cc
+++ b/gdb/testsuite/gdb.cp/nsimport.cc
@@ -13,8 +13,8 @@ namespace{
 
 int main()
 {
-  x;
-  xx;
-  xxx;
+  int unused1 = x;
+  int unused2 = xx;
+  int unused3 = xxx;
   return 0;
 }
diff --git a/gdb/testsuite/gdb.cp/nsnested.cc b/gdb/testsuite/gdb.cp/nsnested.cc
index 9723f87..fc3e11f 100644
--- a/gdb/testsuite/gdb.cp/nsnested.cc
+++ b/gdb/testsuite/gdb.cp/nsnested.cc
@@ -15,7 +15,7 @@ namespace C
     int
     second()
     {
-      ab;
+      int unused = ab;
       return 0;
     }
   }
diff --git a/gdb/testsuite/gdb.cp/nsnoimports.cc b/gdb/testsuite/gdb.cp/nsnoimports.cc
index d1c68ab..9968c35 100644
--- a/gdb/testsuite/gdb.cp/nsnoimports.cc
+++ b/gdb/testsuite/gdb.cp/nsnoimports.cc
@@ -18,9 +18,9 @@ namespace A
     }
 
     int first(){
-      _a;
-      ab;
-      C::abc;
+      int unused1 = _a;
+      int unused2 = ab;
+      int unused3 = C::abc;
       return C::second();
     }
   }
@@ -30,8 +30,8 @@ namespace A
 int
 main()
 {
-  A::_a;
-  A::B::ab;
-  A::B::C::abc;
+  int unused1 = A::_a;
+  int unused2 = A::B::ab;
+  int unused3 = A::B::C::abc;
   return A::B::first();
 }
diff --git a/gdb/testsuite/gdb.cp/nsusing.cc b/gdb/testsuite/gdb.cp/nsusing.cc
index 72ff941..980a91a 100644
--- a/gdb/testsuite/gdb.cp/nsusing.cc
+++ b/gdb/testsuite/gdb.cp/nsusing.cc
@@ -35,7 +35,7 @@ namespace L
   using namespace J;
   int marker8 ()
   {
-    jx;
+    int unused = jx;
     return K::marker9 ();
   }
 }
@@ -53,7 +53,7 @@ namespace I
   int marker7 ()
   {
     using namespace G::H;
-    ghx;
+    int unused = ghx;
     return L::marker8 ();
   }
 }
@@ -69,7 +69,7 @@ namespace E
 using namespace E::F;
 int marker6 ()
 {
-  efx;
+  int unused = efx;
   return I::marker7 ();
 }
 
@@ -92,7 +92,7 @@ namespace D
 using namespace C;
 int marker5 ()
 {
-  cc;
+  int unused = cc;
   return marker6 ();
 }
 
@@ -110,7 +110,7 @@ int marker3 ()
 int marker2 ()
 {
   namespace B = A;
-  B::_a;
+  int unused = B::_a;
   return marker3 ();
 }
 
@@ -134,6 +134,6 @@ int marker1 ()
 int main ()
 {
   using namespace A;
-  _a;
+  int unused = _a;
   return marker1 ();
 }
diff --git a/gdb/testsuite/gdb.cp/smartp.cc b/gdb/testsuite/gdb.cp/smartp.cc
index 2e71d1a..ed52102 100644
--- a/gdb/testsuite/gdb.cp/smartp.cc
+++ b/gdb/testsuite/gdb.cp/smartp.cc
@@ -131,12 +131,12 @@ int main(){
   sp3->foo(1);
   sp3->foo('a');
 
-  sp4->a;
-  sp4->b;
+  int unused1 = sp4->a;
+  int unused2 = sp4->b;
 
   Type4 *mt4p = &mt4;
-  mt4p->a;
-  mt4p->b;
+  int unused3 = mt4p->a;
+  int unused4 = mt4p->b;
 
   A a;
   B b;
diff --git a/gdb/testsuite/gdb.python/py-pp-integral.c b/gdb/testsuite/gdb.python/py-pp-integral.c
index 5cefc00..eadb466 100644
--- a/gdb/testsuite/gdb.python/py-pp-integral.c
+++ b/gdb/testsuite/gdb.python/py-pp-integral.c
@@ -17,10 +17,10 @@
 
 typedef long time_t;
 
-static void
+static time_t
 tick_tock (time_t *t)
 {
-  *t++;
+  return *t++;
 }
 
 int
diff --git a/gdb/testsuite/gdb.python/py-pp-re-notag.c b/gdb/testsuite/gdb.python/py-pp-re-notag.c
index 5cefc00..eadb466 100644
--- a/gdb/testsuite/gdb.python/py-pp-re-notag.c
+++ b/gdb/testsuite/gdb.python/py-pp-re-notag.c
@@ -17,10 +17,10 @@
 
 typedef long time_t;
 
-static void
+static time_t
 tick_tock (time_t *t)
 {
-  *t++;
+  return *t++;
 }
 
 int
-- 
1.8.3.1

Re: [OB PATCH] Avoid testcase build failures with -Wunused-value

[Pedro Alves]

On 6/23/20 12:26 PM, Gary Benson via Gdb-patches wrote:
> --- a/gdb/testsuite/gdb.cp/namespace.cc
> +++ b/gdb/testsuite/gdb.cp/namespace.cc
> @@ -150,22 +150,22 @@ namespace C
>        // plan to have GDB try to print out, just to make sure that the
>        // compiler and I agree which ones should be legal!  It's easy
>        // to screw up when testing the boundaries of namespace stuff.
> -      c;
> +      int unused1 = c;

It looks like such a fix will only work until the compiler decides
to enable -Wunused-variable by default too:

testsuite/gdb.cp/namespace.cc:153:11: warning: unused variable 'unused' [-Wunused-variable]
      int unused = c;
          ^

Try compiling the testcase with -Wall, with both g++ and clang++:

 $ clang++ testsuite/gdb.cp/namespace.cc -Wall

I think we should fix this with the more usual cast-to-void way:

 (void) c;

etc.

Re: [OB PATCH] Avoid testcase build failures with -Wunused-value

[Gary Benson]

Pedro Alves wrote:
> On 6/23/20 12:26 PM, Gary Benson via Gdb-patches wrote:
> > --- a/gdb/testsuite/gdb.cp/namespace.cc
> > +++ b/gdb/testsuite/gdb.cp/namespace.cc
> > @@ -150,22 +150,22 @@ namespace C
> >        // plan to have GDB try to print out, just to make sure that the
> >        // compiler and I agree which ones should be legal!  It's easy
> >        // to screw up when testing the boundaries of namespace stuff.
> > -      c;
> > +      int unused1 = c;
> 
> It looks like such a fix will only work until the compiler decides
> to enable -Wunused-variable by default too:
> 
> testsuite/gdb.cp/namespace.cc:153:11: warning: unused variable 'unused' [-Wunused-variable]
>       int unused = c;
>           ^
> 
> Try compiling the testcase with -Wall, with both g++ and clang++:
> 
>  $ clang++ testsuite/gdb.cp/namespace.cc -Wall
> 
> I think we should fix this with the more usual cast-to-void way:
> 
>  (void) c;

Ok, but, out of interest, what stops the compiler ignoring that?

Thanks,
Gary

Re: [OB PATCH] Avoid testcase build failures with -Wunused-value

[Pedro Alves]

On 6/23/20 12:45 PM, Gary Benson wrote:
> Pedro Alves wrote:
>> On 6/23/20 12:26 PM, Gary Benson via Gdb-patches wrote:
>>> --- a/gdb/testsuite/gdb.cp/namespace.cc
>>> +++ b/gdb/testsuite/gdb.cp/namespace.cc
>>> @@ -150,22 +150,22 @@ namespace C
>>>        // plan to have GDB try to print out, just to make sure that the
>>>        // compiler and I agree which ones should be legal!  It's easy
>>>        // to screw up when testing the boundaries of namespace stuff.
>>> -      c;
>>> +      int unused1 = c;
>>
>> It looks like such a fix will only work until the compiler decides
>> to enable -Wunused-variable by default too:
>>
>> testsuite/gdb.cp/namespace.cc:153:11: warning: unused variable 'unused' [-Wunused-variable]
>>       int unused = c;
>>           ^
>>
>> Try compiling the testcase with -Wall, with both g++ and clang++:
>>
>>  $ clang++ testsuite/gdb.cp/namespace.cc -Wall
>>
>> I think we should fix this with the more usual cast-to-void way:
>>
>>  (void) c;
> 
> Ok, but, out of interest, what stops the compiler ignoring that?

I don't know.  That's a pattern people have been using ages,
it may be special cased.

Thanks,
Pedro Alves

[OB PATCH] Improve -Wunused-value testcase build failures fix

[Gary Benson]

This commit improves upon my previous -Wunused-value fix by
replacing the various dummy variables with casts to void, as
suggested by Pedro.

gdb/testsuite/ChangeLog:

	* gdb.cp/namespace.cc: Improve -Wunused-value fix.
	* gdb.cp/nsimport.cc: Likewise.
	* gdb.cp/nsnested.cc: Likewise.
	* gdb.cp/nsnoimports.cc: Likewise.
	* gdb.cp/nsusing.cc: Likewise.
	* gdb.cp/smartp.cc: Likewise.
	* gdb.python/py-pp-integral.c: Likewise.
	* gdb.python/py-pp-re-notag.c: Likewise.
---
 gdb/testsuite/ChangeLog                   | 12 ++++++++++++
 gdb/testsuite/gdb.cp/namespace.cc         | 22 +++++++++++-----------
 gdb/testsuite/gdb.cp/nsimport.cc          |  6 +++---
 gdb/testsuite/gdb.cp/nsnested.cc          |  2 +-
 gdb/testsuite/gdb.cp/nsnoimports.cc       | 12 ++++++------
 gdb/testsuite/gdb.cp/nsusing.cc           | 12 ++++++------
 gdb/testsuite/gdb.cp/smartp.cc            |  8 ++++----
 gdb/testsuite/gdb.python/py-pp-integral.c |  4 ++--
 gdb/testsuite/gdb.python/py-pp-re-notag.c |  4 ++--
 9 files changed, 47 insertions(+), 35 deletions(-)

diff --git a/gdb/testsuite/gdb.cp/namespace.cc b/gdb/testsuite/gdb.cp/namespace.cc
index 1ff3426..8c78a7e 100644
--- a/gdb/testsuite/gdb.cp/namespace.cc
+++ b/gdb/testsuite/gdb.cp/namespace.cc
@@ -150,22 +150,22 @@ namespace C
       // plan to have GDB try to print out, just to make sure that the
       // compiler and I agree which ones should be legal!  It's easy
       // to screw up when testing the boundaries of namespace stuff.
-      int unused1 = c;
+      (void) c;
       //cc;
-      int unused2 = C::cc;
-      int unused3 = cd;
+      (void) C::cc;
+      (void) cd;
       //C::D::cd;
-      int unused4 = E::cde;
-      int unused5 = shadow;
+      (void) E::cde;
+      (void) shadow;
       //E::ce;
-      int unused6 = cX;
-      int unused7 = F::cXf;
-      int unused8 = F::cXfX;
-      int unused9 = X;
-      int unusedA = G::Xg;
+      (void) cX;
+      (void) F::cXf;
+      (void) F::cXfX;
+      (void) X;
+      (void) G::Xg;
       //cXOtherFile;
       //XOtherFile;
-      int unusedB = G::XgX;
+      (void) G::XgX;
 
       return;
     }
diff --git a/gdb/testsuite/gdb.cp/nsimport.cc b/gdb/testsuite/gdb.cp/nsimport.cc
index 5fc57b0..92a1090 100644
--- a/gdb/testsuite/gdb.cp/nsimport.cc
+++ b/gdb/testsuite/gdb.cp/nsimport.cc
@@ -13,8 +13,8 @@ namespace{
 
 int main()
 {
-  int unused1 = x;
-  int unused2 = xx;
-  int unused3 = xxx;
+  (void) x;
+  (void) xx;
+  (void) xxx;
   return 0;
 }
diff --git a/gdb/testsuite/gdb.cp/nsnested.cc b/gdb/testsuite/gdb.cp/nsnested.cc
index fc3e11f..ec992b2 100644
--- a/gdb/testsuite/gdb.cp/nsnested.cc
+++ b/gdb/testsuite/gdb.cp/nsnested.cc
@@ -15,7 +15,7 @@ namespace C
     int
     second()
     {
-      int unused = ab;
+      (void) ab;
       return 0;
     }
   }
diff --git a/gdb/testsuite/gdb.cp/nsnoimports.cc b/gdb/testsuite/gdb.cp/nsnoimports.cc
index 9968c35..e3ea874 100644
--- a/gdb/testsuite/gdb.cp/nsnoimports.cc
+++ b/gdb/testsuite/gdb.cp/nsnoimports.cc
@@ -18,9 +18,9 @@ namespace A
     }
 
     int first(){
-      int unused1 = _a;
-      int unused2 = ab;
-      int unused3 = C::abc;
+      (void) _a;
+      (void) ab;
+      (void) C::abc;
       return C::second();
     }
   }
@@ -30,8 +30,8 @@ namespace A
 int
 main()
 {
-  int unused1 = A::_a;
-  int unused2 = A::B::ab;
-  int unused3 = A::B::C::abc;
+  (void) A::_a;
+  (void) A::B::ab;
+  (void) A::B::C::abc;
   return A::B::first();
 }
diff --git a/gdb/testsuite/gdb.cp/nsusing.cc b/gdb/testsuite/gdb.cp/nsusing.cc
index 980a91a..fa5c9d0 100644
--- a/gdb/testsuite/gdb.cp/nsusing.cc
+++ b/gdb/testsuite/gdb.cp/nsusing.cc
@@ -35,7 +35,7 @@ namespace L
   using namespace J;
   int marker8 ()
   {
-    int unused = jx;
+    (void) jx;
     return K::marker9 ();
   }
 }
@@ -53,7 +53,7 @@ namespace I
   int marker7 ()
   {
     using namespace G::H;
-    int unused = ghx;
+    (void) ghx;
     return L::marker8 ();
   }
 }
@@ -69,7 +69,7 @@ namespace E
 using namespace E::F;
 int marker6 ()
 {
-  int unused = efx;
+  (void) efx;
   return I::marker7 ();
 }
 
@@ -92,7 +92,7 @@ namespace D
 using namespace C;
 int marker5 ()
 {
-  int unused = cc;
+  (void) cc;
   return marker6 ();
 }
 
@@ -110,7 +110,7 @@ int marker3 ()
 int marker2 ()
 {
   namespace B = A;
-  int unused = B::_a;
+  (void) B::_a;
   return marker3 ();
 }
 
@@ -134,6 +134,6 @@ int marker1 ()
 int main ()
 {
   using namespace A;
-  int unused = _a;
+  (void) _a;
   return marker1 ();
 }
diff --git a/gdb/testsuite/gdb.cp/smartp.cc b/gdb/testsuite/gdb.cp/smartp.cc
index ed52102..eaae77f 100644
--- a/gdb/testsuite/gdb.cp/smartp.cc
+++ b/gdb/testsuite/gdb.cp/smartp.cc
@@ -131,12 +131,12 @@ int main(){
   sp3->foo(1);
   sp3->foo('a');
 
-  int unused1 = sp4->a;
-  int unused2 = sp4->b;
+  (void) sp4->a;
+  (void) sp4->b;
 
   Type4 *mt4p = &mt4;
-  int unused3 = mt4p->a;
-  int unused4 = mt4p->b;
+  (void) mt4p->a;
+  (void) mt4p->b;
 
   A a;
   B b;
diff --git a/gdb/testsuite/gdb.python/py-pp-integral.c b/gdb/testsuite/gdb.python/py-pp-integral.c
index eadb466..cd7c914 100644
--- a/gdb/testsuite/gdb.python/py-pp-integral.c
+++ b/gdb/testsuite/gdb.python/py-pp-integral.c
@@ -17,10 +17,10 @@
 
 typedef long time_t;
 
-static time_t
+static void
 tick_tock (time_t *t)
 {
-  return *t++;
+  (void) *t++;
 }
 
 int
diff --git a/gdb/testsuite/gdb.python/py-pp-re-notag.c b/gdb/testsuite/gdb.python/py-pp-re-notag.c
index eadb466..cd7c914 100644
--- a/gdb/testsuite/gdb.python/py-pp-re-notag.c
+++ b/gdb/testsuite/gdb.python/py-pp-re-notag.c
@@ -17,10 +17,10 @@
 
 typedef long time_t;
 
-static time_t
+static void
 tick_tock (time_t *t)
 {
-  return *t++;
+  (void) *t++;
 }
 
 int
-- 
1.8.3.1