[Sema] Disable -Wbitwise-op-parentheses and -Wlogical-op-parentheses by default

Summary:
The -Wparentheses warnings are enabled by default in clang but they are under
-Wall in gcc (gcc/c-family/c.opt). Some of the operator precedence warnings are
oftentimes criticized as noise (clang: default; gcc: -Wall). If a warning is
very controversial, it is probably not a good idea to enable it by default.
This patch disables the rather annoying ones:

-Wbitwise-op-parentheses, e.g. i & i | i
-Wlogical-op-parentheses, e.g. i && i || i

After this change:

```
* = enabled by default

-Wall
  -Wparentheses
    -Wlogical-op-parentheses
    -Wlogical-not-parentheses*
    -Wbitwise-op-parentheses
    -Wshift-op-parentheses*
    -Woverloaded-shift-op-parentheses*
    -Wparentheses-equality*
    -Wdangling-else*
```

-Woverloaded-shift-op-parentheses is typically followed by overload
resolution failure. We can instead improve the error message, and
probably delete -Woverloaded-shift-op-parentheses in the future. Keep it
for now because it gives some diagnostics.

Reviewers: akyrtzi, jyknight, rtrieu, rsmith, aaron.ballman

Reviewed By: aaron.ballman

Subscribers: dexonsmith, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D65192

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@367690 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/include/clang/Basic/DiagnosticSemaKinds.td b/include/clang/Basic/DiagnosticSemaKinds.td
index 2704a56e430bbe1eb1cb8ec0e35994194b9e9445..cf036b57608fcc7a5be901cfb3686082b1bdd7e6 100644 (file)
--- a/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/include/clang/Basic/DiagnosticSemaKinds.td
@@ -5642,10 +5642,10 @@ def note_logical_instead_of_bitwise_remove_constant : Note<
   "remove constant to silence this warning">;
 
 def warn_bitwise_op_in_bitwise_op : Warning<
-  "'%0' within '%1'">, InGroup<BitwiseOpParentheses>;
+  "'%0' within '%1'">, InGroup<BitwiseOpParentheses>, DefaultIgnore;
 
 def warn_logical_and_in_logical_or : Warning<
-  "'&&' within '||'">, InGroup<LogicalOpParentheses>;
+  "'&&' within '||'">, InGroup<LogicalOpParentheses>, DefaultIgnore;
 
 def warn_overloaded_shift_in_comparison :Warning<
   "overloaded operator %select{>>|<<}0 has higher precedence than "

diff --git a/test/Sema/bitwise-op-parentheses.c b/test/Sema/bitwise-op-parentheses.c
new file mode 100644 (file)
index 0000000..ed270de
--- /dev/null
+++ b/test/Sema/bitwise-op-parentheses.c
@@ -0,0 +1,58 @@
+// RUN: %clang_cc1 -fsyntax-only -verify %s -DSILENCE
+// RUN: %clang_cc1 -fsyntax-only -verify %s -Wbitwise-op-parentheses
+// RUN: %clang_cc1 -fsyntax-only -verify %s -Wparentheses
+// RUN: %clang_cc1 -fsyntax-only -fdiagnostics-parseable-fixits %s -Wbitwise-op-parentheses 2>&1 | FileCheck %s
+
+#ifdef SILENCE
+// expected-no-diagnostics
+#endif
+
+void bitwise_op_parentheses(unsigned i) {
+  (void)(i & i | i);
+#ifndef SILENCE
+  // expected-warning@-2 {{'&' within '|'}}
+  // expected-note@-3 {{place parentheses around the '&' expression to silence this warning}}
+#endif
+  // CHECK: fix-it:"{{.*}}":{[[@LINE-5]]:10-[[@LINE-5]]:10}:"("
+  // CHECK: fix-it:"{{.*}}":{[[@LINE-6]]:15-[[@LINE-6]]:15}:")"
+
+  (void)(i | i & i);
+#ifndef SILENCE
+  // expected-warning@-2 {{'&' within '|'}}
+  // expected-note@-3 {{place parentheses around the '&' expression to silence this warning}}
+#endif
+  // CHECK: fix-it:"{{.*}}":{[[@LINE-5]]:14-[[@LINE-5]]:14}:"("
+  // CHECK: fix-it:"{{.*}}":{[[@LINE-6]]:19-[[@LINE-6]]:19}:")"
+
+  (void)(i ^ i | i);
+#ifndef SILENCE
+  // expected-warning@-2 {{'^' within '|'}}
+  // expected-note@-3 {{place parentheses around the '^' expression to silence this warning}}
+#endif
+  // CHECK: fix-it:"{{.*}}":{[[@LINE-5]]:10-[[@LINE-5]]:10}:"("
+  // CHECK: fix-it:"{{.*}}":{[[@LINE-6]]:15-[[@LINE-6]]:15}:")"
+
+  (void)(i | i ^ i);
+#ifndef SILENCE
+  // expected-warning@-2 {{'^' within '|'}}
+  // expected-note@-3 {{place parentheses around the '^' expression to silence this warning}}
+#endif
+  // CHECK: fix-it:"{{.*}}":{[[@LINE-5]]:14-[[@LINE-5]]:14}:"("
+  // CHECK: fix-it:"{{.*}}":{[[@LINE-6]]:19-[[@LINE-6]]:19}:")"
+
+  (void)(i & i ^ i);
+#ifndef SILENCE
+  // expected-warning@-2 {{'&' within '^'}}
+  // expected-note@-3 {{place parentheses around the '&' expression to silence this warning}}
+#endif
+  // CHECK: fix-it:"{{.*}}":{[[@LINE-5]]:10-[[@LINE-5]]:10}:"("
+  // CHECK: fix-it:"{{.*}}":{[[@LINE-6]]:15-[[@LINE-6]]:15}:")"
+
+  (void)(i ^ i & i);
+#ifndef SILENCE
+  // expected-warning@-2 {{'&' within '^'}}
+  // expected-note@-3 {{place parentheses around the '&' expression to silence this warning}}
+#endif
+  // CHECK: fix-it:"{{.*}}":{[[@LINE-5]]:14-[[@LINE-5]]:14}:"("
+  // CHECK: fix-it:"{{.*}}":{[[@LINE-6]]:19-[[@LINE-6]]:19}:")"
+}

diff --git a/test/Sema/logical-op-parentheses.c b/test/Sema/logical-op-parentheses.c
new file mode 100644 (file)
index 0000000..84464b4
--- /dev/null
+++ b/test/Sema/logical-op-parentheses.c
@@ -0,0 +1,41 @@
+// RUN: %clang_cc1 -fsyntax-only -verify %s -DSILENCE
+// RUN: %clang_cc1 -fsyntax-only -verify %s -Wlogical-op-parentheses
+// RUN: %clang_cc1 -fsyntax-only -verify %s -Wparentheses
+// RUN: %clang_cc1 -fsyntax-only -fdiagnostics-parseable-fixits %s -Wlogical-op-parentheses 2>&1 | FileCheck %s
+
+#ifdef SILENCE
+// expected-no-diagnostics
+#endif
+
+void logical_op_parentheses(unsigned i) {
+  (void)(i ||
+             i && i);
+#ifndef SILENCE
+  // expected-warning@-2 {{'&&' within '||'}}
+  // expected-note@-3 {{place parentheses around the '&&' expression to silence this warning}}
+#endif
+  // CHECK: fix-it:"{{.*}}":{[[@LINE-5]]:14-[[@LINE-5]]:14}:"("
+  // CHECK: fix-it:"{{.*}}":{[[@LINE-6]]:20-[[@LINE-6]]:20}:")"
+
+  (void)(i || i && "w00t");
+  (void)("w00t" && i || i);
+
+  (void)(i || i && "w00t" || i);
+#ifndef SILENCE
+  // expected-warning@-2 {{'&&' within '||'}}
+  // expected-note@-3 {{place parentheses around the '&&' expression to silence this warning}}
+#endif
+  // CHECK: fix-it:"{{.*}}":{[[@LINE-5]]:15-[[@LINE-5]]:15}:"("
+  // CHECK: fix-it:"{{.*}}":{[[@LINE-6]]:26-[[@LINE-6]]:26}:")"
+
+  (void)(i || "w00t" && i || i);
+#ifndef SILENCE
+  // expected-warning@-2 {{'&&' within '||'}}
+  // expected-note@-3 {{place parentheses around the '&&' expression to silence this warning}}
+#endif
+  // CHECK: fix-it:"{{.*}}":{[[@LINE-5]]:15-[[@LINE-5]]:15}:"("
+  // CHECK: fix-it:"{{.*}}":{[[@LINE-6]]:26-[[@LINE-6]]:26}:")"
+
+  (void)(i && i || 0);
+  (void)(0 || i && i);
+}

diff --git a/test/Sema/parentheses.c b/test/Sema/parentheses.c
index 8c6c4999f73a100ef38652ab3847d15b67c2780f..0dabc11d39136bc1697ea9e4137706a736fbd58b 100644 (file)
--- a/test/Sema/parentheses.c
+++ b/test/Sema/parentheses.c
@@ -1,3 +1,4 @@
+// RUN: %clang_cc1 -fsyntax-only -verify %s
 // RUN: %clang_cc1 -Wparentheses -fsyntax-only -verify %s
 // RUN: %clang_cc1 -Wparentheses -fsyntax-only -fdiagnostics-parseable-fixits %s 2>&1 | FileCheck %s
 
@@ -44,58 +45,6 @@ void bitwise_rel(unsigned i) {
   // Eager logical op
   (void)(i == 1 | i == 2 | i == 3);
   (void)(i != 1 & i != 2 & i != 3);
-
-  (void)(i & i | i); // expected-warning {{'&' within '|'}} \
-                     // expected-note {{place parentheses around the '&' expression to silence this warning}}
-  // CHECK: fix-it:"{{.*}}":{[[@LINE-2]]:10-[[@LINE-2]]:10}:"("
-  // CHECK: fix-it:"{{.*}}":{[[@LINE-3]]:15-[[@LINE-3]]:15}:")"
-
-  (void)(i | i & i); // expected-warning {{'&' within '|'}} \
-                     // expected-note {{place parentheses around the '&' expression to silence this warning}}
-  // CHECK: fix-it:"{{.*}}":{[[@LINE-2]]:14-[[@LINE-2]]:14}:"("
-  // CHECK: fix-it:"{{.*}}":{[[@LINE-3]]:19-[[@LINE-3]]:19}:")"
-
-  (void)(i ^ i | i); // expected-warning {{'^' within '|'}} \
-                     // expected-note {{place parentheses around the '^' expression to silence this warning}}
-  // CHECK: fix-it:"{{.*}}":{[[@LINE-2]]:10-[[@LINE-2]]:10}:"("
-  // CHECK: fix-it:"{{.*}}":{[[@LINE-3]]:15-[[@LINE-3]]:15}:")"
-
-  (void)(i | i ^ i); // expected-warning {{'^' within '|'}} \
-                     // expected-note {{place parentheses around the '^' expression to silence this warning}}
-  // CHECK: fix-it:"{{.*}}":{[[@LINE-2]]:14-[[@LINE-2]]:14}:"("
-  // CHECK: fix-it:"{{.*}}":{[[@LINE-3]]:19-[[@LINE-3]]:19}:")"
-
-  (void)(i & i ^ i); // expected-warning {{'&' within '^'}} \
-                     // expected-note {{place parentheses around the '&' expression to silence this warning}}
-  // CHECK: fix-it:"{{.*}}":{[[@LINE-2]]:10-[[@LINE-2]]:10}:"("
-  // CHECK: fix-it:"{{.*}}":{[[@LINE-3]]:15-[[@LINE-3]]:15}:")"
-
-  (void)(i ^ i & i); // expected-warning {{'&' within '^'}} \
-                     // expected-note {{place parentheses around the '&' expression to silence this warning}}
-  // CHECK: fix-it:"{{.*}}":{[[@LINE-2]]:14-[[@LINE-2]]:14}:"("
-  // CHECK: fix-it:"{{.*}}":{[[@LINE-3]]:19-[[@LINE-3]]:19}:")"
-
-  (void)(i ||
-             i && i); // expected-warning {{'&&' within '||'}} \
-                      // expected-note {{place parentheses around the '&&' expression to silence this warning}}
-  // CHECK: fix-it:"{{.*}}":{[[@LINE-2]]:14-[[@LINE-2]]:14}:"("
-  // CHECK: fix-it:"{{.*}}":{[[@LINE-3]]:20-[[@LINE-3]]:20}:")"
-
-  (void)(i || i && "w00t"); // no warning.
-  (void)("w00t" && i || i); // no warning.
-
-  (void)(i || i && "w00t" || i); // expected-warning {{'&&' within '||'}} \
-                                 // expected-note {{place parentheses around the '&&' expression to silence this warning}}
-  // CHECK: fix-it:"{{.*}}":{[[@LINE-2]]:15-[[@LINE-2]]:15}:"("
-  // CHECK: fix-it:"{{.*}}":{[[@LINE-3]]:26-[[@LINE-3]]:26}:")"
-
-  (void)(i || "w00t" && i || i); // expected-warning {{'&&' within '||'}} \
-                                 // expected-note {{place parentheses around the '&&' expression to silence this warning}}
-  // CHECK: fix-it:"{{.*}}":{[[@LINE-2]]:15-[[@LINE-2]]:15}:"("
-  // CHECK: fix-it:"{{.*}}":{[[@LINE-3]]:26-[[@LINE-3]]:26}:")"
-
-  (void)(i && i || 0); // no warning.
-  (void)(0 || i && i); // no warning.
 }
 
 _Bool someConditionFunc();

diff --git a/test/SemaCXX/parentheses.cpp b/test/SemaCXX/parentheses.cpp
index b430b25e5d68376cff7dacbf1d533490275162b9..d466bd01389b5c99b63c01be8217287a63902cb3 100644 (file)
--- a/test/SemaCXX/parentheses.cpp
+++ b/test/SemaCXX/parentheses.cpp
@@ -1,4 +1,4 @@
-// RUN: %clang_cc1 -verify %s
+// RUN: %clang_cc1 -verify -Wlogical-op-parentheses %s
 
 // PR16930, PR16727:
 template<class Foo>