Files
RedBear-OS/local/recipes/dev/libclc/source/clang/test/CodeGenCXX/control-flow-in-stmt-expr.cpp
T
vasilito cb424d7448 build: static patch-sanity linter (shift-left the malformed-patch class)
verify-patch-sanity.py validates every active recipe .patch has internally-
consistent hunk line counts — catching the 'malformed patch at line N' failure
at commit/CI/preflight time instead of hours into a cook. This cycle hit that
class three times (qtwaylandscanner, sddm, xwayland), each only discovered when
cookbook tried to apply the patch.

Running it across the repo found 29 latent malformed patches (validated against
GNU patch: e.g. relibc/P3-sysv-ipc reproduces 'malformed patch at line 22').
They were harmless only because they sit in vendored recipes (baked, not re-
applied) — but would fail on any version-bump re-derivation. --fix recounts the
hunk headers (body untouched) and repaired all 29.

Wired into build-preflight.sh (Phase 1.0D) and redbear-ci.yml, with a unit test
(test-patch-sanity.sh). Skips archived/legacy trees and unvalidatable formats
(empty placeholders, bare-@@ git hunks).
2026-08-01 05:13:02 +03:00

521 lines
20 KiB
C++

// RUN: %clang_cc1 --std=c++20 -fexceptions -triple x86_64-linux-gnu -emit-llvm %s -o - | FileCheck -check-prefixes=EH %s
// RUN: %clang_cc1 --std=c++20 -triple x86_64-linux-gnu -emit-llvm %s -o - | FileCheck -check-prefixes=NOEH,CHECK %s
struct Printy {
Printy(const char *name) : name(name) {}
~Printy() {}
const char *name;
};
int foo() { return 2; }
struct Printies {
Printy a;
Printy b;
Printy c;
};
void ParenInit() {
// CHECK-LABEL: define dso_local void @_Z9ParenInitv()
// CHECK: [[CLEANUP_DEST:%.+]] = alloca i32, align 4
Printies ps(Printy("a"),
// CHECK: call void @_ZN6PrintyC1EPKc
({
if (foo()) return;
// CHECK: if.then:
// CHECK-NEXT: store i32 1, ptr [[CLEANUP_DEST]], align 4
// CHECK-NEXT: br label %cleanup
Printy("b");
// CHECK: if.end:
// CHECK-NEXT: call void @_ZN6PrintyC1EPKc
}),
({
if (foo()) return;
// CHECK: if.then{{.*}}:
// CHECK-NEXT: store i32 1, ptr [[CLEANUP_DEST]], align 4
// CHECK-NEXT: call void @_ZN6PrintyD1Ev
// CHECK-NEXT: br label %cleanup
Printy("c");
// CHECK: if.end{{.*}}:
// CHECK-NEXT: call void @_ZN6PrintyC1EPKc
// CHECK-NEXT: call void @_ZN8PrintiesD1Ev
// CHECK-NEXT: br label %return
}));
// CHECK: cleanup:
// CHECK-NEXT: call void @_ZN6PrintyD1Ev
// CHECK-NEXT: br label %return
}
void break_in_stmt_expr() {
// Verify that the "break" in "if.then".calls dtor before jumping to "for.end".
// CHECK-LABEL: define dso_local void @_Z18break_in_stmt_exprv()
Printies p{Printy("a"),
// CHECK: call void @_ZN6PrintyC1EPKc
({
for (;;) {
Printies ps{
Printy("b"),
// CHECK: for.cond:
// CHECK: call void @_ZN6PrintyC1EPKc
({
if (foo()) {
break;
// CHECK: if.then:
// CHECK-NEXT: call void @_ZN6PrintyD1Ev
// CHECK-NEXT: br label %for.end
}
Printy("c");
// CHECK: if.end:
// CHECK-NEXT: call void @_ZN6PrintyC1EPKc
}),
Printy("d")};
// CHECK: call void @_ZN6PrintyC1EPKc
// CHECK-NEXT: call void @_ZN8PrintiesD1Ev
// CHECK-NEXT: br label %for.cond
}
Printy("e");
// CHECK: for.end:
// CHECK-NEXT: call void @_ZN6PrintyC1EPKc
}),
Printy("f")};
// CHECK: call void @_ZN6PrintyC1EPKc
// CHECK-NEXT: call void @_ZN8PrintiesD1Ev
}
void goto_in_stmt_expr() {
// Verify that:
// - correct branch fixups for deactivated normal cleanups are generated correctly.
// CHECK-LABEL: define dso_local void @_Z17goto_in_stmt_exprv()
// CHECK: [[CLEANUP_DEST_SLOT:%cleanup.dest.slot.*]] = alloca i32, align 4
{
Printies p1{Printy("a"), // CHECK: call void @_ZN6PrintyC1EPKc
({
{
Printies p2{Printy("b"),
// CHECK: call void @_ZN6PrintyC1EPKc
({
if (foo() == 1) {
goto in;
// CHECK: if.then:
// CHECK-NEXT: store i32 2, ptr [[CLEANUP_DEST_SLOT]], align 4
// CHECK-NEXT: br label %[[CLEANUP1:.+]]
}
if (foo() == 2) {
goto out;
// CHECK: if.then{{.*}}:
// CHECK-NEXT: store i32 3, ptr [[CLEANUP_DEST_SLOT]], align 4
// CHECK-NEXT: br label %[[CLEANUP1]]
}
Printy("c");
// CHECK: if.end{{.*}}:
// CHECK-NEXT: call void @_ZN6PrintyC1EPKc
}),
Printy("d")};
// CHECK: call void @_ZN6PrintyC1EPKc
// CHECK-NEXT: call void @_ZN8PrintiesD1Ev
// CHECK-NEXT: br label %in
}
in:
Printy("e");
// CHECK: in: ; preds = %if.end{{.*}}, %[[CLEANUP1]]
// CHECK-NEXT: call void @_ZN6PrintyC1EPKc
}),
Printy("f")};
// CHECK: call void @_ZN6PrintyC1EPKc
// CHECK-NEXT: call void @_ZN8PrintiesD1Ev
// CHECK-NEXT: br label %out
}
out:
return;
// CHECK: out:
// CHECK-NEXT: ret void
// CHECK: [[CLEANUP1]]: ; preds = %if.then{{.*}}, %if.then
// CHECK-NEXT: call void @_ZN6PrintyD1Ev
// CHECK-NEXT: %cleanup.dest = load i32, ptr [[CLEANUP_DEST_SLOT]], align 4
// CHECK-NEXT: switch i32 %cleanup.dest, label %[[CLEANUP2:.+]] [
// CHECK-NEXT: i32 2, label %in
// CHECK-NEXT: ]
// CHECK: [[CLEANUP2]]: ; preds = %[[CLEANUP1]]
// CHECK-NEXT: call void @_ZN6PrintyD1Ev
// CHECK-NEXT: %cleanup.dest{{.*}} = load i32, ptr [[CLEANUP_DEST_SLOT]], align 4
// CHECK-NEXT: switch i32 %cleanup.dest{{.*}}, label %unreachable [
// CHECK-NEXT: i32 3, label %out
// CHECK-NEXT: ]
}
void ArrayInit() {
// Printy arr[4] = {ctorA, ctorB, stmt-exprC, stmt-exprD};
// Verify that:
// - We do the necessary stores for array cleanups (endOfInit and last constructed element).
// - We update the array init element correctly for ctorA, ctorB and stmt-exprC.
// - stmt-exprC and stmt-exprD share the array body dtor code (see %cleanup).
// CHECK-LABEL: define dso_local void @_Z9ArrayInitv()
// CHECK: %arrayinit.endOfInit = alloca ptr, align 8
// CHECK: %cleanup.dest.slot = alloca i32, align 4
// CHECK: store ptr %arr, ptr %arrayinit.endOfInit, align 8
Printy arr[4] = {
Printy("a"),
// CHECK: call void @_ZN6PrintyC1EPKc(ptr noundef nonnull align 8 dereferenceable(8) %arr, ptr noundef @.str)
// CHECK: [[ARRAYINIT_ELEMENT1:%.+]] = getelementptr inbounds %struct.Printy, ptr %arr, i64 1
// CHECK: store ptr [[ARRAYINIT_ELEMENT1]], ptr %arrayinit.endOfInit, align 8
Printy("b"),
// CHECK: call void @_ZN6PrintyC1EPKc(ptr noundef nonnull align 8 dereferenceable(8) [[ARRAYINIT_ELEMENT1]], ptr noundef @.str.1)
// CHECK: [[ARRAYINIT_ELEMENT2:%.+]] = getelementptr inbounds %struct.Printy, ptr %arr, i64 2
// CHECK: store ptr [[ARRAYINIT_ELEMENT2]], ptr %arrayinit.endOfInit, align 8
({
// CHECK: br i1 {{.*}}, label %if.then, label %if.end
if (foo()) {
return;
// CHECK: if.then:
// CHECK-NEXT: store i32 1, ptr %cleanup.dest.slot, align 4
// CHECK-NEXT: br label %cleanup
}
// CHECK: if.end:
Printy("c");
// CHECK-NEXT: call void @_ZN6PrintyC1EPKc
// CHECK-NEXT: %arrayinit.element2 = getelementptr inbounds %struct.Printy, ptr %arr, i64 3
// CHECK-NEXT: store ptr %arrayinit.element2, ptr %arrayinit.endOfInit, align 8
}),
({
// CHECK: br i1 {{%.+}} label %[[IF_THEN2:.+]], label %[[IF_END2:.+]]
if (foo()) {
return;
// CHECK: [[IF_THEN2]]:
// CHECK-NEXT: store i32 1, ptr %cleanup.dest.slot, align 4
// CHECK-NEXT: br label %cleanup
}
// CHECK: [[IF_END2]]:
Printy("d");
// CHECK-NEXT: call void @_ZN6PrintyC1EPKc
// CHECK-NEXT: %array.begin = getelementptr inbounds [4 x %struct.Printy], ptr %arr, i32 0, i32 0
// CHECK-NEXT: %0 = getelementptr inbounds %struct.Printy, ptr %array.begin, i64 4
// CHECK-NEXT: br label %[[ARRAY_DESTROY_BODY1:.+]]
}),
};
// CHECK: [[ARRAY_DESTROY_BODY1]]:
// CHECK-NEXT: %arraydestroy.elementPast{{.*}} = phi ptr [ %0, %[[IF_END2]] ], [ %arraydestroy.element{{.*}}, %[[ARRAY_DESTROY_BODY1]] ]
// CHECK-NEXT: %arraydestroy.element{{.*}} = getelementptr inbounds %struct.Printy, ptr %arraydestroy.elementPast{{.*}}, i64 -1
// CHECK-NEXT: call void @_ZN6PrintyD1Ev
// CHECK-NEXT: %arraydestroy.done{{.*}} = icmp eq ptr %arraydestroy.element{{.*}}, %array.begin
// CHECK-NEXT: br i1 %arraydestroy.done{{.*}}, label %[[ARRAY_DESTROY_DONE1:.+]], label %[[ARRAY_DESTROY_BODY1]]
// CHECK: [[ARRAY_DESTROY_DONE1]]:
// CHECK-NEXT: ret void
// CHECK: cleanup:
// CHECK-NEXT: %1 = load ptr, ptr %arrayinit.endOfInit, align 8
// CHECK-NEXT: %arraydestroy.isempty = icmp eq ptr %arr, %1
// CHECK-NEXT: br i1 %arraydestroy.isempty, label %[[ARRAY_DESTROY_DONE2:.+]], label %[[ARRAY_DESTROY_BODY2:.+]]
// CHECK: [[ARRAY_DESTROY_BODY2]]:
// CHECK-NEXT: %arraydestroy.elementPast = phi ptr [ %1, %cleanup ], [ %arraydestroy.element, %[[ARRAY_DESTROY_BODY2]] ]
// CHECK-NEXT: %arraydestroy.element = getelementptr inbounds %struct.Printy, ptr %arraydestroy.elementPast, i64 -1
// CHECK-NEXT: call void @_ZN6PrintyD1Ev(ptr noundef nonnull align 8 dereferenceable(8) %arraydestroy.element)
// CHECK-NEXT: %arraydestroy.done = icmp eq ptr %arraydestroy.element, %arr
// CHECK-NEXT: br i1 %arraydestroy.done, label %[[ARRAY_DESTROY_DONE2]], label %[[ARRAY_DESTROY_BODY2]]
// CHECK: [[ARRAY_DESTROY_DONE2]]:
// CHECK-NEXT: br label %[[ARRAY_DESTROY_DONE1]]
}
void ArraySubobjects() {
struct S {
Printy arr1[2];
Printy arr2[2];
Printy p;
};
// CHECK-LABEL: define dso_local void @_Z15ArraySubobjectsv()
// CHECK: %arrayinit.endOfInit = alloca ptr, align 8
S s{{Printy("a"), Printy("b")},
// CHECK: call void @_ZN6PrintyC1EPKc
// CHECK: call void @_ZN6PrintyC1EPKc
{Printy("a"),
// CHECK: store ptr %arr2, ptr %arrayinit.endOfInit, align 8
// CHECK: call void @_ZN6PrintyC1EPKc
// CHECK: [[ARRAYINIT_ELEMENT:%.+]] = getelementptr inbounds %struct.Printy
// CHECK: store ptr [[ARRAYINIT_ELEMENT]], ptr %arrayinit.endOfInit, align 8
({
if (foo()) {
return;
// CHECK: if.then:
// CHECK-NEXT: [[V0:%.+]] = load ptr, ptr %arrayinit.endOfInit, align 8
// CHECK-NEXT: %arraydestroy.isempty = icmp eq ptr %arr2, [[V0]]
// CHECK-NEXT: br i1 %arraydestroy.isempty, label %[[ARRAY_DESTROY_DONE:.+]], label %[[ARRAY_DESTROY_BODY:.+]]
}
Printy("b");
})
},
Printy("c")
// CHECK: if.end:
// CHECK-NEXT: call void @_ZN6PrintyC1EPKc
// CHECK: call void @_ZN6PrintyC1EPKc
// CHECK-NEXT: call void @_ZZ15ArraySubobjectsvEN1SD1Ev
// CHECK-NEXT: br label %return
};
// CHECK: return:
// CHECK-NEXT: ret void
// CHECK: [[ARRAY_DESTROY_BODY]]:
// CHECK-NEXT: %arraydestroy.elementPast = phi ptr [ %0, %if.then ], [ %arraydestroy.element, %[[ARRAY_DESTROY_BODY]] ]
// CHECK-NEXT: %arraydestroy.element = getelementptr inbounds %struct.Printy, ptr %arraydestroy.elementPast, i64 -1
// CHECK-NEXT: call void @_ZN6PrintyD1Ev(ptr noundef nonnull align 8 dereferenceable(8) %arraydestroy.element)
// CHECK-NEXT: %arraydestroy.done = icmp eq ptr %arraydestroy.element, %arr2
// CHECK-NEXT: br i1 %arraydestroy.done, label %[[ARRAY_DESTROY_DONE]], label %[[ARRAY_DESTROY_BODY]]
// CHECK: [[ARRAY_DESTROY_DONE]]
// CHECK-NEXT: [[ARRAY_BEGIN:%.+]] = getelementptr inbounds [2 x %struct.Printy], ptr %arr1, i32 0, i32 0
// CHECK-NEXT: [[V1:%.+]] = getelementptr inbounds %struct.Printy, ptr [[ARRAY_BEGIN]], i64 2
// CHECK-NEXT: br label %[[ARRAY_DESTROY_BODY2:.+]]
// CHECK: [[ARRAY_DESTROY_BODY2]]:
// CHECK-NEXT: %arraydestroy.elementPast4 = phi ptr [ %1, %[[ARRAY_DESTROY_DONE]] ], [ %arraydestroy.element5, %[[ARRAY_DESTROY_BODY2]] ]
// CHECK-NEXT: %arraydestroy.element5 = getelementptr inbounds %struct.Printy, ptr %arraydestroy.elementPast4, i64 -1
// CHECK-NEXT: call void @_ZN6PrintyD1Ev(ptr noundef nonnull align 8 dereferenceable(8) %arraydestroy.element5)
// CHECK-NEXT: %arraydestroy.done6 = icmp eq ptr %arraydestroy.element5, [[ARRAY_BEGIN]]
// CHECK-NEXT: br i1 %arraydestroy.done6, label %[[ARRAY_DESTROY_DONE2:.+]], label %[[ARRAY_DESTROY_BODY2]]
// CHECK: [[ARRAY_DESTROY_DONE2]]:
// CHECK-NEXT: br label %return
}
void LambdaInit() {
// CHECK-LABEL: define dso_local void @_Z10LambdaInitv()
auto S = [a = Printy("a"), b = ({
if (foo()) {
return;
// CHECK: if.then:
// CHECK-NEXT: call void @_ZN6PrintyD1Ev
// CHECK-NEXT: br label %return
}
Printy("b");
})]() { return a; };
}
struct PrintyRefBind {
const Printy &a;
const Printy &b;
};
struct Temp {
Temp();
~Temp();
};
Temp CreateTemp();
Printy CreatePrinty();
Printy CreatePrinty(const Temp&);
void LifetimeExtended() {
// CHECK-LABEL: define dso_local void @_Z16LifetimeExtendedv
PrintyRefBind ps = {Printy("a"), ({
if (foo()) {
return;
// CHECK: if.then:
// CHECK-NEXT: call void @_ZN6PrintyD1Ev
// CHECK-NEXT: br label %return
}
Printy("b");
})};
}
void ConditionalLifetimeExtended() {
// CHECK-LABEL: @_Z27ConditionalLifetimeExtendedv()
// Verify that we create two cleanup flags.
// 1. First for the cleanup which is deactivated after full expression.
// 2. Second for the life-ext cleanup which is activated if the branch is taken.
// Note: We use `CreateTemp()` to ensure that life-ext destroy cleanup is not at
// the top of EHStack on deactivation. This ensures using active flags.
Printy* p1 = nullptr;
// CHECK: store i1 false, ptr [[BRANCH1_DEFERRED:%cleanup.cond]], align 1
// CHECK-NEXT: store i1 false, ptr [[BRANCH1_LIFEEXT:%cleanup.cond.*]], align 1
PrintyRefBind ps = {
p1 != nullptr ? static_cast<const Printy&>(CreatePrinty())
// CHECK: cond.true:
// CHECK-NEXT: call void @_Z12CreatePrintyv
// CHECK-NEXT: store i1 true, ptr [[BRANCH1_DEFERRED]], align 1
// CHECK-NEXT: store i1 true, ptr [[BRANCH1_LIFEEXT]], align 1
// CHECK-NEXT: br label %{{.*}}
: foo() ? static_cast<const Printy&>(CreatePrinty(CreateTemp()))
: *p1,
({
if (foo()) return;
Printy("c");
// CHECK: if.end:
// CHECK-NEXT: call void @_ZN6PrintyC1EPKc
// CHECK-NEXT: store ptr
})};
// CHECK-NEXT: store i1 false, ptr [[BRANCH1_DEFERRED]], align 1
// CHECK-NEXT: store i32 0, ptr %cleanup.dest.slot, align 4
// CHECK-NEXT: br label %cleanup
}
void NewArrayInit() {
// CHECK-LABEL: define dso_local void @_Z12NewArrayInitv()
// CHECK: %array.init.end = alloca ptr, align 8
// CHECK: store ptr %0, ptr %array.init.end, align 8
Printy *array = new Printy[3]{
"a",
// CHECK: call void @_ZN6PrintyC1EPKc
// CHECK: store ptr %array.exp.next, ptr %array.init.end, align 8
"b",
// CHECK: call void @_ZN6PrintyC1EPKc
// CHECK: store ptr %array.exp.next1, ptr %array.init.end, align 8
({
if (foo()) {
return;
// CHECK: if.then:
// CHECK: br i1 %arraydestroy.isempty, label %arraydestroy.done{{.*}}, label %arraydestroy.body
}
"b";
// CHECK: if.end:
// CHECK: call void @_ZN6PrintyC1EPKc
})};
// CHECK: arraydestroy.body:
// CHECK-NEXT: %arraydestroy.elementPast = phi ptr [ %{{.*}}, %if.then ], [ %arraydestroy.element, %arraydestroy.body ]
// CHECK-NEXT: %arraydestroy.element = getelementptr inbounds %struct.Printy, ptr %arraydestroy.elementPast, i64 -1
// CHECK-NEXT: call void @_ZN6PrintyD1Ev(ptr noundef nonnull align 8 dereferenceable(8) %arraydestroy.element)
// CHECK-NEXT: %arraydestroy.done = icmp eq ptr %arraydestroy.element, %0
// CHECK-NEXT: br i1 %arraydestroy.done, label %arraydestroy.done{{.*}}, label %arraydestroy.body
// CHECK: arraydestroy.done{{.*}}: ; preds = %arraydestroy.body, %if.then
// CHECK-NEXT: br label %return
}
void DestroyInConditionalCleanup() {
// EH-LABEL: DestroyInConditionalCleanupv()
// NOEH-LABEL: DestroyInConditionalCleanupv()
struct A {
A() {}
~A() {}
};
struct Value {
Value(A) {}
~Value() {}
};
struct V2 {
Value K;
Value V;
};
// Verify we use conditional cleanups.
(void)(foo() ? V2{A(), A()} : V2{A(), A()});
// NOEH: cond.true:
// NOEH: call void @_ZZ27DestroyInConditionalCleanupvEN1AC1Ev
// NOEH: store ptr %{{.*}}, ptr %cond-cleanup.save
// EH: cond.true:
// EH: invoke void @_ZZ27DestroyInConditionalCleanupvEN1AC1Ev
// EH: store ptr %{{.*}}, ptr %cond-cleanup.save
}
void ArrayInitWithContinue() {
// CHECK-LABEL: @_Z21ArrayInitWithContinuev
// Verify that we start to emit the array destructor.
// CHECK: %arrayinit.endOfInit = alloca ptr, align 8
for (int i = 0; i < 1; ++i) {
Printy arr[2] = {"a", ({
if (foo()) {
continue;
}
"b";
})};
}
}
struct [[clang::trivial_abi]] HasTrivialABI {
HasTrivialABI();
~HasTrivialABI();
};
void AcceptTrivialABI(HasTrivialABI, int);
void TrivialABI() {
// CHECK-LABEL: define dso_local void @_Z10TrivialABIv()
AcceptTrivialABI(HasTrivialABI(), ({
if (foo()) return;
// CHECK: if.then:
// CHECK-NEXT: call void @_ZN13HasTrivialABID1Ev
// CHECK-NEXT: br label %return
0;
}));
}
namespace CleanupFlag {
struct A {
A() {}
~A() {}
};
struct B {
B(const A&) {}
B() {}
~B() {}
};
struct S {
A a;
B b;
};
int AcceptS(S s);
void Accept2(int x, int y);
void InactiveNormalCleanup() {
// CHECK-LABEL: define {{.*}}InactiveNormalCleanupEv()
// The first A{} below is an inactive normal cleanup which
// is not popped from EHStack on deactivation. This needs an
// "active" cleanup flag.
// CHECK: [[ACTIVE:%cleanup.isactive.*]] = alloca i1, align 1
// CHECK: call void [[A_CTOR:@.*AC1Ev]]
// CHECK: store i1 true, ptr [[ACTIVE]], align 1
// CHECK: call void [[A_CTOR]]
// CHECK: call void [[B_CTOR:@.*BC1ERKNS_1AE]]
// CHECK: store i1 false, ptr [[ACTIVE]], align 1
// CHECK: call noundef i32 [[ACCEPTS:@.*AcceptSENS_1SE]]
Accept2(AcceptS({.a = A{}, .b = A{}}), ({
if (foo()) return;
// CHECK: if.then:
// CHECK: br label %cleanup
0;
// CHECK: if.end:
// CHECK: call void [[ACCEPT2:@.*Accept2Eii]]
// CHECK: br label %cleanup
}));
// CHECK: cleanup:
// CHECK: call void [[S_DTOR:@.*SD1Ev]]
// CHECK: call void [[A_DTOR:@.*AD1Ev]]
// CHECK: %cleanup.is_active = load i1, ptr [[ACTIVE]]
// CHECK: br i1 %cleanup.is_active, label %cleanup.action, label %cleanup.done
// CHECK: cleanup.action:
// CHECK: call void [[A_DTOR]]
// The "active" cleanup flag is not required for unused cleanups.
Accept2(AcceptS({.a = A{}, .b = A{}}), 0);
// CHECK: cleanup.cont:
// CHECK: call void [[A_CTOR]]
// CHECK-NOT: store i1 true
// CHECK: call void [[A_CTOR]]
// CHECK: call void [[B_CTOR]]
// CHECK-NOT: store i1 false
// CHECK: call noundef i32 [[ACCEPTS]]
// CHECK: call void [[ACCEPT2]]
// CHECK: call void [[S_DTOR]]
// CHECK: call void [[A_DTOR]]
// CHECK: br label %return
}
} // namespace CleanupFlag