This revision was automatically updated to reflect the committed changes.
Closed by commit rG82afc9b169a6: Fix -Wbitfield-constant-conversion on 1-bit
signed bitfield (authored by ShawnZhong, committed by aaron.ballman).
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D131255/new/
https://reviews.llvm.org/D131255
Files:
clang/docs/ReleaseNotes.rst
clang/lib/Sema/SemaChecking.cpp
clang/test/CXX/class/class.bit/p1.cpp
clang/test/CXX/drs/dr6xx.cpp
clang/test/CodeGen/bitfield.c
clang/test/CodeGenCXX/bitfield-layout.cpp
clang/test/Rewriter/rewrite-modern-struct-ivar-1.mm
clang/test/Rewriter/rewrite-modern-struct-ivar.mm
clang/test/Sema/constant-conversion.c
clang/test/SemaCXX/constant-expression-cxx11.cpp
clang/test/SemaCXX/cxx1z-decomposition.cpp
clang/test/SemaCXX/decomposition-blocks.cpp
Index: clang/test/SemaCXX/decomposition-blocks.cpp
===================================================================
--- clang/test/SemaCXX/decomposition-blocks.cpp
+++ clang/test/SemaCXX/decomposition-blocks.cpp
@@ -7,7 +7,7 @@
void run(void (^)());
void test() {
- auto [i, j] = S{1, 42}; // expected-note {{'i' declared here}}
+ auto [i, j] = S{-1, 42}; // expected-note {{'i' declared here}}
run(^{
(void)i; // expected-error {{reference to local binding 'i' declared in enclosing function 'test'}}
});
Index: clang/test/SemaCXX/cxx1z-decomposition.cpp
===================================================================
--- clang/test/SemaCXX/cxx1z-decomposition.cpp
+++ clang/test/SemaCXX/cxx1z-decomposition.cpp
@@ -84,7 +84,7 @@
(void)[outerbit1]{}; // expected-error {{'outerbit1' cannot be captured because it does not have automatic storage duration}}
- auto [bit, var] = S2{1, 1}; // expected-note 2{{'bit' declared here}}
+ auto [bit, var] = S2{-1, 1}; // expected-note 2{{'bit' declared here}}
(void)[&bit] { // expected-error {{non-const reference cannot bind to bit-field 'a'}} \
// expected-warning {{C++20}}
Index: clang/test/SemaCXX/constant-expression-cxx11.cpp
===================================================================
--- clang/test/SemaCXX/constant-expression-cxx11.cpp
+++ clang/test/SemaCXX/constant-expression-cxx11.cpp
@@ -2035,6 +2035,7 @@
}
};
static_assert(X::f(3) == -1, "3 should truncate to -1");
+ static_assert(X::f(1) == -1, "1 should truncate to -1");
}
struct HasUnnamedBitfield {
Index: clang/test/Sema/constant-conversion.c
===================================================================
--- clang/test/Sema/constant-conversion.c
+++ clang/test/Sema/constant-conversion.c
@@ -15,8 +15,16 @@
}
void test(void) {
- struct { int bit : 1; } a;
- a.bit = 1; // shouldn't warn
+ struct S {
+ int b : 1; // The only valid values are 0 and -1.
+ } s;
+
+ s.b = -3; // expected-warning {{implicit truncation from 'int' to bit-field changes value from -3 to -1}}
+ s.b = -2; // expected-warning {{implicit truncation from 'int' to bit-field changes value from -2 to 0}}
+ s.b = -1; // no-warning
+ s.b = 0; // no-warning
+ s.b = 1; // expected-warning {{implicit truncation from 'int' to bit-field changes value from 1 to -1}}
+ s.b = 2; // expected-warning {{implicit truncation from 'int' to bit-field changes value from 2 to 0}}
}
enum Test2 { K_zero, K_one };
Index: clang/test/Rewriter/rewrite-modern-struct-ivar.mm
===================================================================
--- clang/test/Rewriter/rewrite-modern-struct-ivar.mm
+++ clang/test/Rewriter/rewrite-modern-struct-ivar.mm
@@ -41,10 +41,10 @@
@implementation Foo
- (void)x {
bar.x = 0;
- bar.y = 1;
+ bar.y = -1;
s.x = 0;
- s.y = 1;
+ s.y = -1;
}
@end
Index: clang/test/Rewriter/rewrite-modern-struct-ivar-1.mm
===================================================================
--- clang/test/Rewriter/rewrite-modern-struct-ivar-1.mm
+++ clang/test/Rewriter/rewrite-modern-struct-ivar-1.mm
@@ -34,7 +34,7 @@
@implementation Foo
- (void)x:(Foo *)other {
bar.x = 0;
- bar.y = 1;
+ bar.y = -1;
self->_internal._singleRange._range = (( other ->bar.x) ? &( other ->_internal._singleRange._range) : ((NSRange *)(&(((_NSRangeInfo *)( other ->_internal._multipleRanges._data))->_ranges))))[0];
}
@end
Index: clang/test/CodeGenCXX/bitfield-layout.cpp
===================================================================
--- clang/test/CodeGenCXX/bitfield-layout.cpp
+++ clang/test/CodeGenCXX/bitfield-layout.cpp
@@ -105,6 +105,15 @@
// CHECK: define{{.*}} i32 @test_trunc_three_bits()
// CHECK: ret i32 -1
+int test_trunc_one_bit() {
+ union {
+ int i : 1; // truncated to 0b1 == -1
+ } const U = {1}; // 0b00000001
+ return U.i;
+}
+// CHECK: define{{.*}} i32 @test_trunc_one_bit()
+// CHECK: ret i32 -1
+
int test_trunc_1() {
union {
int i : 1; // truncated to 0b1 == -1
Index: clang/test/CodeGen/bitfield.c
===================================================================
--- clang/test/CodeGen/bitfield.c
+++ clang/test/CodeGen/bitfield.c
@@ -87,3 +87,19 @@
// PATH: ret i32 1
return f3(20) + 130725747;
}
+
+static int f4(void) {
+ struct s5 {
+ int b:1;
+ } x;
+ x.b = 1;
+ return x.b;
+}
+
+int g4(void) {
+// CHECK-LABEL: @g4()
+// CHECK: ret i32 1
+// PATH-LABEL: @g4()
+// PATH: ret i32 1
+ return f4() + 2;
+}
Index: clang/test/CXX/drs/dr6xx.cpp
===================================================================
--- clang/test/CXX/drs/dr6xx.cpp
+++ clang/test/CXX/drs/dr6xx.cpp
@@ -911,9 +911,9 @@
namespace dr675 { // dr675: dup 739
template<typename T> struct A { T n : 1; };
#if __cplusplus >= 201103L
- static_assert(A<char>{1}.n < 0, "");
- static_assert(A<int>{1}.n < 0, "");
- static_assert(A<long long>{1}.n < 0, "");
+ static_assert(A<char>{1}.n < 0, ""); // expected-warning {{implicit truncation from 'int' to bit-field changes value from 1 to -1}}
+ static_assert(A<int>{1}.n < 0, ""); // expected-warning {{implicit truncation from 'int' to bit-field changes value from 1 to -1}}
+ static_assert(A<long long>{1}.n < 0, ""); // expected-warning {{implicit truncation from 'int' to bit-field changes value from 1 to -1}}
#endif
}
Index: clang/test/CXX/class/class.bit/p1.cpp
===================================================================
--- clang/test/CXX/class/class.bit/p1.cpp
+++ clang/test/CXX/class/class.bit/p1.cpp
@@ -9,11 +9,11 @@
int [[]] c : 1; // OK, attribute applies to the type.
int : 2 = 1; // expected-error {{anonymous bit-field cannot have a default member initializer}}
int : 0 { 1 }; // expected-error {{anonymous bit-field cannot have a default member initializer}}
- int : 0, d : 1 = 1;
+ unsigned int : 0, d : 1 = 1;
int : 1 = 12, e : 1; // expected-error {{anonymous bit-field cannot have a default member initializer}}
- int : 0, f : 1 = 1;
- int g [[]] : 1 = 1;
- int h [[]] : 1 {1};
- int i : foo() = foo();
+ unsigned int : 0, f : 1 = 1;
+ unsigned int g [[]] : 1 = 1;
+ unsigned int h [[]] : 1 {1};
+ unsigned int i : foo() = foo();
int j, [[]] k; // expected-error {{an attribute list cannot appear here}}
};
Index: clang/lib/Sema/SemaChecking.cpp
===================================================================
--- clang/lib/Sema/SemaChecking.cpp
+++ clang/lib/Sema/SemaChecking.cpp
@@ -13064,11 +13064,6 @@
if (llvm::APSInt::isSameValue(Value, TruncatedValue))
return false;
- // Special-case bitfields of width 1: booleans are naturally 0/1, and
- // therefore don't strictly fit into a signed bitfield of width 1.
- if (FieldWidth == 1 && Value == 1)
- return false;
-
std::string PrettyValue = toString(Value, 10);
std::string PrettyTrunc = toString(TruncatedValue, 10);
Index: clang/docs/ReleaseNotes.rst
===================================================================
--- clang/docs/ReleaseNotes.rst
+++ clang/docs/ReleaseNotes.rst
@@ -82,6 +82,9 @@
- ``-Wformat`` now recognizes ``%b`` for the ``printf``/``scanf`` family of
functions and ``%B`` for the ``printf`` family of functions. Fixes
`Issue 56885: <https://github.com/llvm/llvm-project/issues/56885>`_.
+- ``-Wbitfield-constant-conversion`` now diagnoses implicit truncation when 1 is
+ assigned to a 1-bit signed integer bitfield. This fixes
+ `Issue 53253 <https://github.com/llvm/llvm-project/issues/53253>`_.
Non-comprehensive list of changes in this release
-------------------------------------------------
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