hiraditya created this revision.
hiraditya added reviewers: Eugene.Zelenko, rsmith.
We found conversion from bool* to bool to be a common source of bug, so we have
implemented this warning. Sample use case:
int bar(bool b) {
return b;
}
int baz() {
bool *b;
bar(b);
return 0;
}
Typically, there would be a function which takes a bool, which gets a pointer
to boolean at the call site. The compiler currently does not warn which results
in a difficult to debug runtime failure.
https://reviews.llvm.org/D45601
Files:
include/clang/Basic/DiagnosticSemaKinds.td
lib/Sema/SemaChecking.cpp
test/CXX/expr/expr.unary/expr.unary.op/p6.cpp
test/Sema/static-init.c
test/SemaCXX/warn-bool-ptr-to-bool.cpp
Index: test/SemaCXX/warn-bool-ptr-to-bool.cpp
===================================================================
--- /dev/null
+++ test/SemaCXX/warn-bool-ptr-to-bool.cpp
@@ -0,0 +1,23 @@
+// RUN: %clang_cc1 -fsyntax-only -verify %s
+
+int foo(bool *b) {
+ if (b)
+ // expected-warning@-1 {{comparing 'bool *' as a boolean}}
+ return 10;
+ return 0;
+}
+
+
+int bar(bool b) {
+ return b;
+}
+
+int baz() {
+ bool *b;
+ bar(b);
+ // expected-warning@-1 {{comparing 'bool *' as a boolean}}
+ return 0;
+}
+
+
+
Index: test/Sema/static-init.c
===================================================================
--- test/Sema/static-init.c
+++ test/Sema/static-init.c
@@ -7,7 +7,7 @@
float r = (float) (intptr_t) &r; // expected-error {{initializer element is
not a compile-time constant}}
intptr_t s = (intptr_t) &s;
-_Bool t = &t;
+_Bool t = &t; // expected-warning {{comparing '_Bool *' as a boolean}}
union bar {
Index: test/CXX/expr/expr.unary/expr.unary.op/p6.cpp
===================================================================
--- test/CXX/expr/expr.unary/expr.unary.op/p6.cpp
+++ test/CXX/expr/expr.unary/expr.unary.op/p6.cpp
@@ -16,6 +16,7 @@
// -- pointer,
bool b6 = !&b4; // expected-warning{{address of 'b4' will always evaluate to
'true'}}
+// expected-warning@-1 {{comparing 'bool *' as a boolean}}
void f();
bool b61 = !&f;
Index: lib/Sema/SemaChecking.cpp
===================================================================
--- lib/Sema/SemaChecking.cpp
+++ lib/Sema/SemaChecking.cpp
@@ -9610,6 +9610,12 @@
S.DiagnoseAlwaysNonNullPointer(E, Expr::NPCK_NotNull, /*IsEqual*/ false,
SourceRange(CC));
}
+ if (Source->isPointerType() || Source->canDecayToPointerType()) {
+ QualType PointeeType = Source->getPointeeType();
+ // Warn on bool* to bool conversion.
+ if (!PointeeType.isNull() && PointeeType->isBooleanType())
+ return DiagnoseImpCast(S, E, T, CC, diag::warn_pointer_to_bool);
+ }
}
// Check implicit casts from Objective-C collection literals to specialized
Index: include/clang/Basic/DiagnosticSemaKinds.td
===================================================================
--- include/clang/Basic/DiagnosticSemaKinds.td
+++ include/clang/Basic/DiagnosticSemaKinds.td
@@ -7801,6 +7801,9 @@
"format specifies type %0 but the argument has "
"%select{type|underlying type}2 %1">,
InGroup<FormatPedantic>;
+def warn_pointer_to_bool : Warning<
+ "comparing %0 as a boolean">,
+ InGroup<Extra>;
def warn_format_argument_needs_cast : Warning<
"%select{values of type|enum values with underlying type}2 '%0' should not "
"be used as format arguments; add an explicit cast to %1 instead">,
Index: test/SemaCXX/warn-bool-ptr-to-bool.cpp
===================================================================
--- /dev/null
+++ test/SemaCXX/warn-bool-ptr-to-bool.cpp
@@ -0,0 +1,23 @@
+// RUN: %clang_cc1 -fsyntax-only -verify %s
+
+int foo(bool *b) {
+ if (b)
+ // expected-warning@-1 {{comparing 'bool *' as a boolean}}
+ return 10;
+ return 0;
+}
+
+
+int bar(bool b) {
+ return b;
+}
+
+int baz() {
+ bool *b;
+ bar(b);
+ // expected-warning@-1 {{comparing 'bool *' as a boolean}}
+ return 0;
+}
+
+
+
Index: test/Sema/static-init.c
===================================================================
--- test/Sema/static-init.c
+++ test/Sema/static-init.c
@@ -7,7 +7,7 @@
float r = (float) (intptr_t) &r; // expected-error {{initializer element is not a compile-time constant}}
intptr_t s = (intptr_t) &s;
-_Bool t = &t;
+_Bool t = &t; // expected-warning {{comparing '_Bool *' as a boolean}}
union bar {
Index: test/CXX/expr/expr.unary/expr.unary.op/p6.cpp
===================================================================
--- test/CXX/expr/expr.unary/expr.unary.op/p6.cpp
+++ test/CXX/expr/expr.unary/expr.unary.op/p6.cpp
@@ -16,6 +16,7 @@
// -- pointer,
bool b6 = !&b4; // expected-warning{{address of 'b4' will always evaluate to 'true'}}
+// expected-warning@-1 {{comparing 'bool *' as a boolean}}
void f();
bool b61 = !&f;
Index: lib/Sema/SemaChecking.cpp
===================================================================
--- lib/Sema/SemaChecking.cpp
+++ lib/Sema/SemaChecking.cpp
@@ -9610,6 +9610,12 @@
S.DiagnoseAlwaysNonNullPointer(E, Expr::NPCK_NotNull, /*IsEqual*/ false,
SourceRange(CC));
}
+ if (Source->isPointerType() || Source->canDecayToPointerType()) {
+ QualType PointeeType = Source->getPointeeType();
+ // Warn on bool* to bool conversion.
+ if (!PointeeType.isNull() && PointeeType->isBooleanType())
+ return DiagnoseImpCast(S, E, T, CC, diag::warn_pointer_to_bool);
+ }
}
// Check implicit casts from Objective-C collection literals to specialized
Index: include/clang/Basic/DiagnosticSemaKinds.td
===================================================================
--- include/clang/Basic/DiagnosticSemaKinds.td
+++ include/clang/Basic/DiagnosticSemaKinds.td
@@ -7801,6 +7801,9 @@
"format specifies type %0 but the argument has "
"%select{type|underlying type}2 %1">,
InGroup<FormatPedantic>;
+def warn_pointer_to_bool : Warning<
+ "comparing %0 as a boolean">,
+ InGroup<Extra>;
def warn_format_argument_needs_cast : Warning<
"%select{values of type|enum values with underlying type}2 '%0' should not "
"be used as format arguments; add an explicit cast to %1 instead">,
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