Author: rsmith
Date: Fri Dec 2 18:29:06 2016
New Revision: 288558
URL: http://llvm.org/viewvc/llvm-project?rev=288558&view=rev
Log:
PR31244: Use the exception specification from the callee's type directly to
compute whether a call is noexcept, even if we can't map the callee expression
to a called declaration.
Modified:
cfe/trunk/lib/Sema/SemaExceptionSpec.cpp
cfe/trunk/test/SemaCXX/cxx1z-noexcept-function-type.cpp
Modified: cfe/trunk/lib/Sema/SemaExceptionSpec.cpp
URL:
http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaExceptionSpec.cpp?rev=288558&r1=288557&r2=288558&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaExceptionSpec.cpp (original)
+++ cfe/trunk/lib/Sema/SemaExceptionSpec.cpp Fri Dec 2 18:29:06 2016
@@ -944,24 +944,37 @@ static CanThrowResult canSubExprsThrow(S
}
static CanThrowResult canCalleeThrow(Sema &S, const Expr *E, const Decl *D) {
- assert(D && "Expected decl");
-
- // See if we can get a function type from the decl somehow.
- const ValueDecl *VD = dyn_cast<ValueDecl>(D);
- if (!VD) {
- // In C++17, we may have a canonical exception specification. If so, use
it.
- if (auto *FT = E->getType().getCanonicalType()->getAs<FunctionProtoType>())
- return FT->isNothrow(S.Context) ? CT_Cannot : CT_Can;
- // If we have no clue what we're calling, assume the worst.
- return CT_Can;
- }
-
// As an extension, we assume that __attribute__((nothrow)) functions don't
// throw.
- if (isa<FunctionDecl>(D) && D->hasAttr<NoThrowAttr>())
+ if (D && isa<FunctionDecl>(D) && D->hasAttr<NoThrowAttr>())
return CT_Cannot;
- QualType T = VD->getType();
+ QualType T;
+
+ // In C++1z, just look at the function type of the callee.
+ if (S.getLangOpts().CPlusPlus1z && isa<CallExpr>(E)) {
+ E = cast<CallExpr>(E)->getCallee();
+ T = E->getType();
+ if (T->isSpecificPlaceholderType(BuiltinType::BoundMember)) {
+ // Sadly we don't preserve the actual type as part of the "bound member"
+ // placeholder, so we need to reconstruct it.
+ E = E->IgnoreParenImpCasts();
+
+ // Could be a call to a pointer-to-member or a plain member access.
+ if (auto *Op = dyn_cast<BinaryOperator>(E)) {
+ assert(Op->getOpcode() == BO_PtrMemD || Op->getOpcode() == BO_PtrMemI);
+ T = Op->getRHS()->getType()
+ ->castAs<MemberPointerType>()->getPointeeType();
+ } else {
+ T = cast<MemberExpr>(E)->getMemberDecl()->getType();
+ }
+ }
+ } else if (const ValueDecl *VD = dyn_cast_or_null<ValueDecl>(D))
+ T = VD->getType();
+ else
+ // If we have no clue what we're calling, assume the worst.
+ return CT_Can;
+
const FunctionProtoType *FT;
if ((FT = T->getAs<FunctionProtoType>())) {
} else if (const PointerType *PT = T->getAs<PointerType>())
@@ -1053,10 +1066,8 @@ CanThrowResult Sema::canThrow(const Expr
CT = CT_Dependent;
else if (isa<CXXPseudoDestructorExpr>(CE->getCallee()->IgnoreParens()))
CT = CT_Cannot;
- else if (CE->getCalleeDecl())
- CT = canCalleeThrow(*this, E, CE->getCalleeDecl());
else
- CT = CT_Can;
+ CT = canCalleeThrow(*this, E, CE->getCalleeDecl());
if (CT == CT_Can)
return CT;
return mergeCanThrow(CT, canSubExprsThrow(*this, E));
Modified: cfe/trunk/test/SemaCXX/cxx1z-noexcept-function-type.cpp
URL:
http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/cxx1z-noexcept-function-type.cpp?rev=288558&r1=288557&r2=288558&view=diff
==============================================================================
--- cfe/trunk/test/SemaCXX/cxx1z-noexcept-function-type.cpp (original)
+++ cfe/trunk/test/SemaCXX/cxx1z-noexcept-function-type.cpp Fri Dec 2 18:29:06
2016
@@ -30,6 +30,21 @@ auto deduce_auto_from_noexcept_function_
using DeducedType_b = decltype(deduce_auto_from_noexcept_function_ptr_b);
using DeducedType_b = void (*)(int);
+static_assert(noexcept(init_with_exact_type_a(0)));
+static_assert(noexcept((+init_with_exact_type_a)(0)));
+static_assert(!noexcept(init_with_exact_type_b(0)));
+static_assert(!noexcept((+init_with_exact_type_b)(0)));
+
+// Don't look through casts, use the direct type of the expression.
+// FIXME: static_cast here would be reasonable, but is not currently permitted.
+static_assert(noexcept(static_cast<decltype(init_with_exact_type_a)>(init_with_exact_type_b)(0)));
// expected-error {{is not allowed}}
+static_assert(noexcept(reinterpret_cast<decltype(init_with_exact_type_a)>(init_with_exact_type_b)(0)));
+static_assert(!noexcept(static_cast<decltype(init_with_exact_type_b)>(init_with_exact_type_a)(0)));
+
+template<bool B> auto get_fn() noexcept -> void (*)() noexcept(B) {}
+static_assert(noexcept(get_fn<true>()()));
+static_assert(!noexcept(get_fn<false>()()));
+
namespace DependentDefaultCtorExceptionSpec {
template<typename> struct T { static const bool value = true; };
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