[clang] f62d18f - [Clang] Extend -Wbool-operation to warn about bitwise and of bools with side effects
Dávid Bolvanský via cfe-commits
cfe-commits at lists.llvm.org
Sun Oct 3 02:06:47 PDT 2021
Author: Dávid Bolvanský
Date: 2021-10-03T11:06:40+02:00
New Revision: f62d18ff140f67a8776a7a3c62a75645d8d540b5
URL: https://github.com/llvm/llvm-project/commit/f62d18ff140f67a8776a7a3c62a75645d8d540b5
DIFF: https://github.com/llvm/llvm-project/commit/f62d18ff140f67a8776a7a3c62a75645d8d540b5.diff
LOG: [Clang] Extend -Wbool-operation to warn about bitwise and of bools with side effects
Motivation: https://arstechnica.com/gadgets/2021/07/google-pushed-a-one-character-typo-to-production-bricking-chrome-os-devices/
Warn for pattern boolA & boolB or boolA | boolB where boolA and boolB has possible side effects.
Casting one operand to int is enough to silence this warning: for example (int)boolA & boolB or boolA| (int)boolB
Fixes https://bugs.llvm.org/show_bug.cgi?id=51216
Differential Revision: https://reviews.llvm.org/D108003
Added:
clang/test/Sema/warn-bitwise-and-bool.c
clang/test/Sema/warn-bitwise-or-bool.c
Modified:
clang/include/clang/Basic/DiagnosticGroups.td
clang/include/clang/Basic/DiagnosticSemaKinds.td
clang/lib/Sema/SemaChecking.cpp
clang/test/Misc/warning-wall.c
Removed:
################################################################################
diff --git a/clang/include/clang/Basic/DiagnosticGroups.td b/clang/include/clang/Basic/DiagnosticGroups.td
index 761b323d06166..d9db3482dbda7 100644
--- a/clang/include/clang/Basic/DiagnosticGroups.td
+++ b/clang/include/clang/Basic/DiagnosticGroups.td
@@ -64,7 +64,8 @@ def StringConversion : DiagGroup<"string-conversion">;
def SignConversion : DiagGroup<"sign-conversion">;
def PointerBoolConversion : DiagGroup<"pointer-bool-conversion">;
def UndefinedBoolConversion : DiagGroup<"undefined-bool-conversion">;
-def BoolOperation : DiagGroup<"bool-operation">;
+def BitwiseInsteadOfLogical : DiagGroup<"bitwise-instead-of-logical">;
+def BoolOperation : DiagGroup<"bool-operation", [BitwiseInsteadOfLogical]>;
def BoolConversion : DiagGroup<"bool-conversion", [PointerBoolConversion,
UndefinedBoolConversion]>;
def IntConversion : DiagGroup<"int-conversion">;
diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td
index 1d4ea92c65205..c71a00b184328 100644
--- a/clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -66,6 +66,7 @@ def warn_infinite_recursive_function : Warning<
def warn_comma_operator : Warning<"possible misuse of comma operator here">,
InGroup<DiagGroup<"comma">>, DefaultIgnore;
def note_cast_to_void : Note<"cast expression to void to silence warning">;
+def note_cast_operand_to_int : Note<"cast one or both operands to int to silence this warning">;
// Constant expressions
def err_expr_not_ice : Error<
@@ -7423,6 +7424,9 @@ def note_member_declared_here : Note<
"member %0 declared here">;
def note_member_first_declared_here : Note<
"member %0 first declared here">;
+def warn_bitwise_instead_of_logical : Warning<
+ "use of bitwise '%0' with boolean operands">,
+ InGroup<BitwiseInsteadOfLogical>, DefaultIgnore;
def warn_bitwise_negation_bool : Warning<
"bitwise negation of a boolean expression%select{;| always evaluates to 'true';}0 "
"did you mean logical negation?">,
diff --git a/clang/lib/Sema/SemaChecking.cpp b/clang/lib/Sema/SemaChecking.cpp
index 8b53e3504e13a..10a3f30704172 100644
--- a/clang/lib/Sema/SemaChecking.cpp
+++ b/clang/lib/Sema/SemaChecking.cpp
@@ -13249,6 +13249,20 @@ static void AnalyzeImplicitConversions(
<< OrigE->getSourceRange() << T->isBooleanType()
<< FixItHint::CreateReplacement(UO->getBeginLoc(), "!");
+ if (const auto *BO = dyn_cast<BinaryOperator>(SourceExpr))
+ if ((BO->getOpcode() == BO_And || BO->getOpcode() == BO_Or) &&
+ BO->getLHS()->isKnownToHaveBooleanValue() &&
+ BO->getRHS()->isKnownToHaveBooleanValue() &&
+ BO->getLHS()->HasSideEffects(S.Context) &&
+ BO->getRHS()->HasSideEffects(S.Context)) {
+ S.Diag(BO->getBeginLoc(), diag::warn_bitwise_instead_of_logical)
+ << (BO->getOpcode() == BO_And ? "&" : "|") << OrigE->getSourceRange()
+ << FixItHint::CreateReplacement(
+ BO->getOperatorLoc(),
+ (BO->getOpcode() == BO_And ? "&&" : "||"));
+ S.Diag(BO->getBeginLoc(), diag::note_cast_operand_to_int);
+ }
+
// For conditional operators, we analyze the arguments as if they
// were being fed directly into the output.
if (auto *CO = dyn_cast<AbstractConditionalOperator>(SourceExpr)) {
diff --git a/clang/test/Misc/warning-wall.c b/clang/test/Misc/warning-wall.c
index a3686fb96a4ce..a4a79bec934af 100644
--- a/clang/test/Misc/warning-wall.c
+++ b/clang/test/Misc/warning-wall.c
@@ -4,6 +4,7 @@ RUN: FileCheck --input-file=%t %s
CHECK:-Wall
CHECK-NEXT: -Wmost
CHECK-NEXT: -Wbool-operation
+CHECK-NEXT: -Wbitwise-instead-of-logical
CHECK-NEXT: -Wchar-subscripts
CHECK-NEXT: -Wcomment
CHECK-NEXT: -Wdelete-non-virtual-dtor
diff --git a/clang/test/Sema/warn-bitwise-and-bool.c b/clang/test/Sema/warn-bitwise-and-bool.c
new file mode 100644
index 0000000000000..6bec1be1abdef
--- /dev/null
+++ b/clang/test/Sema/warn-bitwise-and-bool.c
@@ -0,0 +1,63 @@
+// RUN: %clang_cc1 -x c -fsyntax-only -verify -Wbool-operation %s
+// RUN: %clang_cc1 -x c -fsyntax-only -verify -Wall %s
+// RUN: %clang_cc1 -x c -fsyntax-only -Wbitwise-instead-of-logical -fdiagnostics-parseable-fixits %s 2>&1 | FileCheck %s
+// RUN: %clang_cc1 -x c -fsyntax-only -Wbool-operation -fdiagnostics-parseable-fixits %s 2>&1 | FileCheck %s
+// RUN: %clang_cc1 -x c++ -fsyntax-only -verify -Wbool-operation %s
+// RUN: %clang_cc1 -x c++ -fsyntax-only -verify -Wall %s
+// RUN: %clang_cc1 -x c++ -fsyntax-only -Wbitwise-instead-of-logical -fdiagnostics-parseable-fixits %s 2>&1 | FileCheck %s
+// RUN: %clang_cc1 -x c++ -fsyntax-only -Wbool-operation -fdiagnostics-parseable-fixits %s 2>&1 | FileCheck %s
+
+#ifdef __cplusplus
+typedef bool boolean;
+#else
+typedef _Bool boolean;
+#endif
+
+boolean foo(void);
+boolean bar(void);
+boolean baz(void) __attribute__((const));
+void sink(boolean);
+
+#define FOO foo()
+
+void test(boolean a, boolean b, int *p, volatile int *q, int i) {
+ b = a & b;
+ b = foo() & a;
+ b = (p != 0) & (*p == 42); // FIXME: also warn for a non-volatile pointer dereference
+ b = foo() & (*q == 42); // expected-warning {{use of bitwise '&' with boolean operands}}
+ // expected-note at -1 {{cast one or both operands to int to silence this warning}}
+ b = foo() & (int)(*q == 42); // OK, no warning expected
+ b = a & foo();
+ b = (int)a & foo(); // OK, no warning expected
+ b = foo() & bar(); // expected-warning {{use of bitwise '&' with boolean operands}}
+ // expected-note at -1 {{cast one or both operands to int to silence this warning}}
+ // CHECK: fix-it:"{{.*}}":{[[@LINE-2]]:13-[[@LINE-2]]:14}:"&&"
+ b = foo() & (int)bar(); // OK, no warning expected
+ b = foo() & !bar(); // expected-warning {{use of bitwise '&' with boolean operands}}
+ // expected-note at -1 {{cast one or both operands to int to silence this warning}}
+ // CHECK: fix-it:"{{.*}}":{[[@LINE-2]]:13-[[@LINE-2]]:14}:"&&"
+ b = a & baz();
+ b = bar() & FOO; // expected-warning {{use of bitwise '&' with boolean operands}}
+ // expected-note at -1 {{cast one or both operands to int to silence this warning}}
+ // CHECK: fix-it:"{{.*}}":{[[@LINE-2]]:13-[[@LINE-2]]:14}:"&&"
+ b = foo() & (int)FOO; // OK, no warning expected
+ b = b & foo();
+ b = bar() & (i > 4);
+ b = (i == 7) & foo();
+#ifdef __cplusplus
+ b = foo() bitand bar(); // expected-warning {{use of bitwise '&' with boolean operands}}
+ // expected-note at -1 {{cast one or both operands to int to silence this warning}}
+#endif
+
+ if (foo() & bar()) // expected-warning {{use of bitwise '&' with boolean operands}}
+ // expected-note at -1 {{cast one or both operands to int to silence this warning}}
+ ;
+
+ sink(a & b);
+ sink(a & foo());
+ sink(foo() & bar()); // expected-warning {{use of bitwise '&' with boolean operands}}
+ // expected-note at -1 {{cast one or both operands to int to silence this warning}}
+
+ int n = i + 10;
+ b = (n & (n - 1));
+}
diff --git a/clang/test/Sema/warn-bitwise-or-bool.c b/clang/test/Sema/warn-bitwise-or-bool.c
new file mode 100644
index 0000000000000..ae86790901aac
--- /dev/null
+++ b/clang/test/Sema/warn-bitwise-or-bool.c
@@ -0,0 +1,63 @@
+// RUN: %clang_cc1 -x c -fsyntax-only -verify -Wbool-operation %s
+// RUN: %clang_cc1 -x c -fsyntax-only -verify -Wall %s
+// RUN: %clang_cc1 -x c -fsyntax-only -Wbitwise-instead-of-logical -fdiagnostics-parseable-fixits %s 2>&1 | FileCheck %s
+// RUN: %clang_cc1 -x c -fsyntax-only -Wbool-operation -fdiagnostics-parseable-fixits %s 2>&1 | FileCheck %s
+// RUN: %clang_cc1 -x c++ -fsyntax-only -verify -Wbool-operation %s
+// RUN: %clang_cc1 -x c++ -fsyntax-only -verify -Wall %s
+// RUN: %clang_cc1 -x c++ -fsyntax-only -Wbitwise-instead-of-logical -fdiagnostics-parseable-fixits %s 2>&1 | FileCheck %s
+// RUN: %clang_cc1 -x c++ -fsyntax-only -Wbool-operation -fdiagnostics-parseable-fixits %s 2>&1 | FileCheck %s
+
+#ifdef __cplusplus
+typedef bool boolean;
+#else
+typedef _Bool boolean;
+#endif
+
+boolean foo(void);
+boolean bar(void);
+boolean baz(void) __attribute__((const));
+void sink(boolean);
+
+#define FOO foo()
+
+void test(boolean a, boolean b, int *p, volatile int *q, int i) {
+ b = a | b;
+ b = foo() | a;
+ b = (p != 0) | (*p == 42); // FIXME: also warn for a non-volatile pointer dereference
+ b = foo() | (*q == 42); // expected-warning {{use of bitwise '|' with boolean operands}}
+ // expected-note at -1 {{cast one or both operands to int to silence this warning}}
+ b = foo() | (int)(*q == 42); // OK, no warning expected
+ b = a | foo();
+ b = (int)a | foo(); // OK, no warning expected
+ b = foo() | bar(); // expected-warning {{use of bitwise '|' with boolean operands}}
+ // expected-note at -1 {{cast one or both operands to int to silence this warning}}
+ // CHECK: fix-it:"{{.*}}":{[[@LINE-2]]:13-[[@LINE-2]]:14}:"||"
+ b = foo() | !bar(); // expected-warning {{use of bitwise '|' with boolean operands}}
+ // expected-note at -1 {{cast one or both operands to int to silence this warning}}
+ // CHECK: fix-it:"{{.*}}":{[[@LINE-2]]:13-[[@LINE-2]]:14}:"||"
+ b = foo() | (int)bar(); // OK, no warning expected
+ b = a | baz();
+ b = bar() | FOO; // expected-warning {{use of bitwise '|' with boolean operands}}
+ // expected-note at -1 {{cast one or both operands to int to silence this warning}}
+ // CHECK: fix-it:"{{.*}}":{[[@LINE-2]]:13-[[@LINE-2]]:14}:"||"
+ b = foo() | (int)FOO; // OK, no warning expected
+ b = b | foo();
+ b = bar() | (i > 4);
+ b = (i == 7) | foo();
+#ifdef __cplusplus
+ b = foo() bitor bar(); // expected-warning {{use of bitwise '|' with boolean operands}}
+ // expected-note at -1 {{cast one or both operands to int to silence this warning}}
+#endif
+
+ if (foo() | bar()) // expected-warning {{use of bitwise '|' with boolean operands}}
+ // expected-note at -1 {{cast one or both operands to int to silence this warning}}
+ ;
+
+ sink(a | b);
+ sink(a | foo());
+ sink(foo() | bar()); // expected-warning {{use of bitwise '|' with boolean operands}}
+ // expected-note at -1 {{cast one or both operands to int to silence this warning}}
+
+ int n = i + 10;
+ b = (n | (n - 1));
+}
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