ychen updated this revision to Diff 351343.
ychen added a comment.
- Add `DiagIfReachable` and use it in `Sema::DiagnoseUnusedExprResult`.
- Update tests.
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D103938/new/
https://reviews.llvm.org/D103938
Files:
clang/include/clang/Sema/Sema.h
clang/lib/Sema/SemaExpr.cpp
clang/lib/Sema/SemaStmt.cpp
clang/test/CXX/drs/dr14xx.cpp
clang/test/CXX/temp/temp.constr/temp.constr.constr/partial-specializations.cpp
clang/test/CodeCompletion/pragma-macro-token-caching.c
clang/test/PCH/cxx-explicit-specifier.cpp
clang/test/Parser/cxx-ambig-decl-expr.cpp
clang/test/Parser/cxx0x-ambig.cpp
clang/test/Sema/const-eval.c
clang/test/Sema/exprs.c
clang/test/Sema/i-c-e.c
clang/test/Sema/vla-2.c
clang/test/SemaCXX/attr-annotate.cpp
clang/test/SemaCXX/builtin-constant-p.cpp
clang/test/SemaCXX/constant-expression-cxx2a.cpp
clang/test/SemaCXX/constant-expression.cpp
clang/test/SemaCXX/expression-traits.cpp
clang/test/SemaCXX/warn-comma-operator.cpp
clang/test/SemaCXX/warn-unused-value.cpp
Index: clang/test/SemaCXX/warn-unused-value.cpp
===================================================================
--- clang/test/SemaCXX/warn-unused-value.cpp
+++ clang/test/SemaCXX/warn-unused-value.cpp
@@ -138,3 +138,13 @@
(void)arr3;
(void)arr4;
}
+
+#if __cplusplus >= 201103L // C++11 or later
+namespace test5 {
+int v[(5, 6)]; // expected-warning {{expression result unused}}
+void foo() {
+ new double[false ? (1, 2) : 3]
+ [false ? (1, 2) : 3]; // expected-warning {{expression result unused}}
+}
+} // namespace test5
+#endif
Index: clang/test/SemaCXX/warn-comma-operator.cpp
===================================================================
--- clang/test/SemaCXX/warn-comma-operator.cpp
+++ clang/test/SemaCXX/warn-comma-operator.cpp
@@ -242,8 +242,8 @@
template <typename... xs>
class Foo {
- typedef bool_seq<(xs::value, true)...> all_true;
- typedef bool_seq<(xs::value, false)...> all_false;
+ typedef bool_seq<((void)xs::value, true)...> all_true;
+ typedef bool_seq<((void)xs::value, false)...> all_false;
typedef bool_seq<xs::value...> seq;
};
Index: clang/test/SemaCXX/expression-traits.cpp
===================================================================
--- clang/test/SemaCXX/expression-traits.cpp
+++ clang/test/SemaCXX/expression-traits.cpp
@@ -583,10 +583,10 @@
// Can't use the ASSERT_XXXX macros without adding parens around
// the comma expression.
- static_assert(__is_lvalue_expr(x,x), "expected an lvalue");
- static_assert(__is_rvalue_expr(x,1), "expected an rvalue");
- static_assert(__is_lvalue_expr(1,x), "expected an lvalue");
- static_assert(__is_rvalue_expr(1,1), "expected an rvalue");
+ static_assert(__is_lvalue_expr((void)x,x), "expected an lvalue");
+ static_assert(__is_rvalue_expr((void)x,1), "expected an rvalue");
+ static_assert(__is_lvalue_expr((void)1,x), "expected an lvalue");
+ static_assert(__is_rvalue_expr((void)1,1), "expected an rvalue");
}
#if 0
Index: clang/test/SemaCXX/constant-expression.cpp
===================================================================
--- clang/test/SemaCXX/constant-expression.cpp
+++ clang/test/SemaCXX/constant-expression.cpp
@@ -88,8 +88,8 @@
void diags(int n) {
switch (n) {
- case (1/0, 1): // expected-error {{not an integral constant expression}} expected-note {{division by zero}}
- case (int)(1/0, 2.0): // expected-error {{not an integral constant expression}} expected-note {{division by zero}}
+ case (1/0, 1): // expected-error {{not an integral constant expression}} expected-note {{division by zero}} expected-warning {{expression result unused}}
+ case (int)(1/0, 2.0): // expected-error {{not an integral constant expression}} expected-note {{division by zero}} expected-warning {{expression result unused}}
case __imag(1/0): // expected-error {{not an integral constant expression}} expected-note {{division by zero}}
case (int)__imag((double)(1/0)): // expected-error {{not an integral constant expression}} expected-note {{division by zero}}
;
Index: clang/test/SemaCXX/constant-expression-cxx2a.cpp
===================================================================
--- clang/test/SemaCXX/constant-expression-cxx2a.cpp
+++ clang/test/SemaCXX/constant-expression-cxx2a.cpp
@@ -745,7 +745,7 @@
// Ensure that we can handle temporary cleanups for array temporaries.
struct ArrElem { constexpr ~ArrElem() {} };
using Arr = ArrElem[3];
- static_assert((Arr{}, true));
+ static_assert(((void)Arr{}, true));
}
namespace dynamic_alloc {
Index: clang/test/SemaCXX/builtin-constant-p.cpp
===================================================================
--- clang/test/SemaCXX/builtin-constant-p.cpp
+++ clang/test/SemaCXX/builtin-constant-p.cpp
@@ -157,12 +157,12 @@
constexpr ~A() { *p = 0; }
};
struct Q { int n; constexpr int *get() { return &n; } };
- static_assert(!__builtin_constant_p((A{}, 123)));
+ static_assert(!__builtin_constant_p(((void)A{}, 123)));
// FIXME: We should probably accept this. GCC does.
// However, GCC appears to do so by running the destructors at the end of the
// enclosing full-expression, which seems broken; running them at the end of
// the evaluation of the __builtin_constant_p argument would be more
// defensible.
- static_assert(!__builtin_constant_p((A{Q().get()}, 123)));
+ static_assert(!__builtin_constant_p(((void)A{Q().get()}, 123)));
}
#endif
Index: clang/test/SemaCXX/attr-annotate.cpp
===================================================================
--- clang/test/SemaCXX/attr-annotate.cpp
+++ clang/test/SemaCXX/attr-annotate.cpp
@@ -42,7 +42,7 @@
template<typename T>
struct B {
- [[clang::annotate("test", (T{}, 9))]] void t() {}
+ [[clang::annotate("test", ((void)T{}, 9))]] void t() {}
// expected-error@-1 {{illegal initializer type 'void'}}
};
B<int> b;
@@ -73,7 +73,7 @@
[[clang::annotate("jui", b, cf)]] void t2() {}
// expected-error@-1 {{'annotate' attribute requires parameter 1 to be a constant expression}}
// expected-note@-2 {{is not allowed in a constant expression}}
- [[clang::annotate("jui", (b, 0), cf)]] [[clang::annotate("jui", &b, cf, &foo::t2, str())]] void t3() {}
+ [[clang::annotate("jui", ((void)b, 0), cf)]] [[clang::annotate("jui", &b, cf, &foo::t2, str())]] void t3() {}
};
};
Index: clang/test/Sema/vla-2.c
===================================================================
--- clang/test/Sema/vla-2.c
+++ clang/test/Sema/vla-2.c
@@ -13,5 +13,5 @@
}
void PotentiallyEvaluatedArrayBoundWarn(int n) {
- (void)*(int(*)[(0 << 32,n)])0; // FIXME: We should warn here.
+ (void)*(int(*)[(0 << 32,n)])0; // expected-warning {{expression result unused}}
}
Index: clang/test/Sema/i-c-e.c
===================================================================
--- clang/test/Sema/i-c-e.c
+++ clang/test/Sema/i-c-e.c
@@ -70,10 +70,12 @@
char z[__builtin_constant_p(4) ? 1 : -1];
// Comma tests
-int comma1[0?1,2:3];
-int comma2[1||(1,2)]; // expected-warning {{use of logical '||' with constant operand}} \
- // expected-note {{use '|' for a bitwise operation}}
-int comma3[(1,2)]; // expected-warning {{variable length array folded to constant array as an extension}}
+int comma1[0?1,2:3]; // expected-warning {{expression result unused}}
+int comma2[1 || (1, 2)]; // expected-warning {{use of logical '||' with constant operand}} \
+ // expected-note {{use '|' for a bitwise operation}} \
+ // expected-warning {{expression result unused}}
+int comma3[(1, 2)]; // expected-warning {{variable length array folded to constant array as an extension}} \
+ // expected-warning {{expression result unused}}
// Pointer + __builtin_constant_p
char pbcp[__builtin_constant_p(4) ? (intptr_t)&expr : 0]; // expected-error {{variable length array declaration not allowed at file scope}}
Index: clang/test/Sema/exprs.c
===================================================================
--- clang/test/Sema/exprs.c
+++ clang/test/Sema/exprs.c
@@ -13,10 +13,9 @@
// Test that we don't report divide-by-zero errors in unreachable code.
-// This test should be left as is, as it also tests CFG functionality.
void radar9171946() {
if (0) {
- 0 / (0 ? 1 : 0); // expected-warning {{expression result unused}}
+ 0 / (0 ? 1 : 0); // no-warning
}
}
Index: clang/test/Sema/const-eval.c
===================================================================
--- clang/test/Sema/const-eval.c
+++ clang/test/Sema/const-eval.c
@@ -74,7 +74,7 @@
EVAL_EXPR(35, constbool)
EVAL_EXPR(36, constbool)
-EVAL_EXPR(37, (1,2.0) == 2.0 ? 1 : -1)
+EVAL_EXPR(37, ((void)1,2.0) == 2.0 ? 1 : -1)
EVAL_EXPR(38, __builtin_expect(1,1) == 1 ? 1 : -1)
// PR7884
Index: clang/test/Parser/cxx0x-ambig.cpp
===================================================================
--- clang/test/Parser/cxx0x-ambig.cpp
+++ clang/test/Parser/cxx0x-ambig.cpp
@@ -163,7 +163,7 @@
(void)p1;
UnsignedTmplArgSink<T(CtorSink(t ...)) ...> *t0; // ok
- UnsignedTmplArgSink<((T *)0, 42u) ...> **t0p = &t0;
+ UnsignedTmplArgSink<((T *)0, 42u) ...> **t0p = &t0; // expected-warning 2{{expression result unused}}
}
template void foo(int, int, int); // expected-note {{in instantiation of function template specialization 'ellipsis::foo<int, int>' requested here}}
Index: clang/test/Parser/cxx-ambig-decl-expr.cpp
===================================================================
--- clang/test/Parser/cxx-ambig-decl-expr.cpp
+++ clang/test/Parser/cxx-ambig-decl-expr.cpp
@@ -36,8 +36,8 @@
int(a[{0}]); // expected-warning {{unused}}
// These are array declarations.
- int(x[(1,1)]); // expected-error {{redefinition}}
- int(x[true ? 1,1 : 1]); // expected-error {{redefinition}}
+ int(x[((void)1,1)]); // expected-error {{redefinition}}
+ int(x[true ? 1 : (1,1)]); // expected-error {{redefinition}} // expected-warning {{unused}}
int (*_Atomic atomic_ptr_to_int);
*atomic_ptr_to_int = 42;
Index: clang/test/PCH/cxx-explicit-specifier.cpp
===================================================================
--- clang/test/PCH/cxx-explicit-specifier.cpp
+++ clang/test/PCH/cxx-explicit-specifier.cpp
@@ -12,7 +12,7 @@
template<typename X, typename Y> struct T {
template<typename A>
- explicit((Y{}, true)) T(A &&a) {}
+ explicit(((void)Y{}, true)) T(A &&a) {}
};
template<typename X, typename Y> struct U : T<X, Y> {
@@ -28,7 +28,7 @@
U<S, char> a = foo('0');
}
-//CHECK: explicit((char{} , true))
+//CHECK: explicit(((void)char{} , true))
#endif
Index: clang/test/CodeCompletion/pragma-macro-token-caching.c
===================================================================
--- clang/test/CodeCompletion/pragma-macro-token-caching.c
+++ clang/test/CodeCompletion/pragma-macro-token-caching.c
@@ -12,7 +12,7 @@
void completeParamPragmaError(int param) {
Outer(__extension__({ _Pragma(2) })); // expected-error {{_Pragma takes a parenthesized string literal}}
- param; // expected-warning {{expression result unused}}
+ param;
}
// RUN: %clang_cc1 -fsyntax-only -verify -code-completion-at=%s:16:1 %s | FileCheck %s
Index: clang/test/CXX/temp/temp.constr/temp.constr.constr/partial-specializations.cpp
===================================================================
--- clang/test/CXX/temp/temp.constr/temp.constr.constr/partial-specializations.cpp
+++ clang/test/CXX/temp/temp.constr/temp.constr.constr/partial-specializations.cpp
@@ -26,7 +26,7 @@
template<typename T> requires (T{}) // expected-error{{atomic constraint must be of type 'bool' (found 'int')}}
struct B<T**> {};
- static_assert((B<int**>{}, true)); // expected-note{{while checking constraint satisfaction for class template partial specialization 'B<int *>' required here}}
+ static_assert(((void)B<int**>{}, true)); // expected-note{{while checking constraint satisfaction for class template partial specialization 'B<int *>' required here}}
// expected-note@-1{{while checking constraint satisfaction for class template partial specialization 'B<int>' required here}}
// expected-note@-2{{during template argument deduction for class template partial specialization 'B<T *>' [with T = int *]}}
// expected-note@-3{{during template argument deduction for class template partial specialization 'B<T **>' [with T = int]}}
Index: clang/test/CXX/drs/dr14xx.cpp
===================================================================
--- clang/test/CXX/drs/dr14xx.cpp
+++ clang/test/CXX/drs/dr14xx.cpp
@@ -18,7 +18,7 @@
Check<true ? 0 : A::unknown_spec>::type *var1; // expected-error {{undeclared identifier 'var1'}}
Check<true ? 0 : a>::type *var2; // ok, variable declaration expected-note 0+{{here}}
Check<true ? 0 : b>::type *var3; // expected-error {{undeclared identifier 'var3'}}
- Check<true ? 0 : (c, 0)>::type *var4; // expected-error {{undeclared identifier 'var4'}}
+ Check<true ? 0 : ((void)c, 0)>::type *var4; // expected-error {{undeclared identifier 'var4'}}
// value-dependent because of the implied type-dependent 'this->', not because of 'd'
Check<true ? 0 : (d(), 0)>::type *var5; // expected-error {{undeclared identifier 'var5'}}
// value-dependent because of the value-dependent '&' operator, not because of 'A::d'
Index: clang/lib/Sema/SemaStmt.cpp
===================================================================
--- clang/lib/Sema/SemaStmt.cpp
+++ clang/lib/Sema/SemaStmt.cpp
@@ -379,7 +379,8 @@
return;
}
- DiagRuntimeBehavior(Loc, nullptr, PDiag(DiagID) << R1 << R2);
+ DiagIfReachable(Loc, S ? llvm::makeArrayRef(S) : llvm::None,
+ PDiag(DiagID) << R1 << R2);
}
void Sema::ActOnStartOfCompoundStmt(bool IsStmtExpr) {
Index: clang/lib/Sema/SemaExpr.cpp
===================================================================
--- clang/lib/Sema/SemaExpr.cpp
+++ clang/lib/Sema/SemaExpr.cpp
@@ -18779,6 +18779,37 @@
EvaluatedExprMarker(*this, SkipLocalVariables).Visit(E);
}
+/// Emit a diagnostic when statements are reachable.
+/// FIXME: check for reachability even in expressions for which we don't build a
+/// CFG (eg, in the initializer of a global or in a constant expression).
+/// For example,
+/// namespace { auto *p = new double[3][false ? (1, 2) : 3]; }
+bool Sema::DiagIfReachable(SourceLocation Loc, ArrayRef<const Stmt *> Stmts,
+ const PartialDiagnostic &PD) {
+ if (!Stmts.empty() && !FunctionScopes.empty()) {
+ FunctionScopes.back()->PossiblyUnreachableDiags.push_back(
+ sema::PossiblyUnreachableDiag(PD, Loc, Stmts));
+ return true;
+ }
+
+ // The initializer of a constexpr variable or of the first declaration of a
+ // static data member is not syntactically a constant evaluated constant,
+ // but nonetheless is always required to be a constant expression, so we
+ // can skip diagnosing.
+ // FIXME: Using the mangling context here is a hack.
+ if (auto *VD = dyn_cast_or_null<VarDecl>(
+ ExprEvalContexts.back().ManglingContextDecl)) {
+ if (VD->isConstexpr() ||
+ (VD->isStaticDataMember() && VD->isFirstDecl() && !VD->isInline()))
+ return false;
+ // FIXME: For any other kind of variable, we should build a CFG for its
+ // initializer and check whether the context in question is reachable.
+ }
+
+ Diag(Loc, PD);
+ return true;
+}
+
/// Emit a diagnostic that describes an effect on the run-time behavior
/// of the program being compiled.
///
@@ -18811,28 +18842,7 @@
case ExpressionEvaluationContext::PotentiallyEvaluated:
case ExpressionEvaluationContext::PotentiallyEvaluatedIfUsed:
- if (!Stmts.empty() && getCurFunctionOrMethodDecl()) {
- FunctionScopes.back()->PossiblyUnreachableDiags.
- push_back(sema::PossiblyUnreachableDiag(PD, Loc, Stmts));
- return true;
- }
-
- // The initializer of a constexpr variable or of the first declaration of a
- // static data member is not syntactically a constant evaluated constant,
- // but nonetheless is always required to be a constant expression, so we
- // can skip diagnosing.
- // FIXME: Using the mangling context here is a hack.
- if (auto *VD = dyn_cast_or_null<VarDecl>(
- ExprEvalContexts.back().ManglingContextDecl)) {
- if (VD->isConstexpr() ||
- (VD->isStaticDataMember() && VD->isFirstDecl() && !VD->isInline()))
- break;
- // FIXME: For any other kind of variable, we should build a CFG for its
- // initializer and check whether the context in question is reachable.
- }
-
- Diag(Loc, PD);
- return true;
+ return DiagIfReachable(Loc, Stmts, PD);
}
return false;
Index: clang/include/clang/Sema/Sema.h
===================================================================
--- clang/include/clang/Sema/Sema.h
+++ clang/include/clang/Sema/Sema.h
@@ -5077,6 +5077,16 @@
/// conversion.
ExprResult tryConvertExprToType(Expr *E, QualType Ty);
+ /// Conditionally issue a diagnostic based on the statements reachability
+ /// analysis evaluation context.
+ ///
+ /// \param Statement If Statement is non-null, delay reporting the
+ /// diagnostic until the function body is parsed, and then do a basic
+ /// reachability analysis to determine if the statement is reachable.
+ /// If it is unreachable, the diagnostic will not be emitted.
+ bool DiagIfReachable(SourceLocation Loc, ArrayRef<const Stmt *> Stmts,
+ const PartialDiagnostic &PD);
+
/// Conditionally issue a diagnostic based on the current
/// evaluation context.
///
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