This revision was automatically updated to reflect the committed changes.
Closed by commit rL263887: [Sema] Allow casting of some overloaded functions
(authored by gbiv).
Changed prior to commit:
http://reviews.llvm.org/D17701?vs=49334&id=51119#toc
Repository:
rL LLVM
http://reviews.llvm.org/D17701
Files:
cfe/trunk/include/clang/Sema/Sema.h
cfe/trunk/lib/Sema/SemaCast.cpp
cfe/trunk/lib/Sema/SemaOverload.cpp
cfe/trunk/test/SemaCXX/enable_if.cpp
cfe/trunk/test/SemaCXX/unaddressable-functions.cpp
Index: cfe/trunk/include/clang/Sema/Sema.h
===================================================================
--- cfe/trunk/include/clang/Sema/Sema.h
+++ cfe/trunk/include/clang/Sema/Sema.h
@@ -2507,6 +2507,10 @@
bool *pHadMultipleCandidates = nullptr);
FunctionDecl *
+ resolveAddressOfOnlyViableOverloadCandidate(Expr *E,
+ DeclAccessPair &FoundResult);
+
+ FunctionDecl *
ResolveSingleFunctionTemplateSpecialization(OverloadExpr *ovl,
bool Complain = false,
DeclAccessPair *Found = nullptr);
Index: cfe/trunk/test/SemaCXX/enable_if.cpp
===================================================================
--- cfe/trunk/test/SemaCXX/enable_if.cpp
+++ cfe/trunk/test/SemaCXX/enable_if.cpp
@@ -253,3 +253,96 @@
a = &noOvlNoCandidate; // expected-error{{cannot take address of function 'noOvlNoCandidate' becuase it has one or more non-tautological enable_if conditions}}
}
}
+
+namespace casting {
+using VoidFnTy = void (*)();
+
+void foo(void *c) __attribute__((enable_if(0, "")));
+void foo(int *c) __attribute__((enable_if(c, "")));
+void foo(char *c) __attribute__((enable_if(1, "")));
+
+void testIt() {
+ auto A = reinterpret_cast<VoidFnTy>(foo);
+ auto AAmp = reinterpret_cast<VoidFnTy>(&foo);
+
+ using VoidFooTy = void (*)(void *);
+ auto B = reinterpret_cast<VoidFooTy>(foo);
+ auto BAmp = reinterpret_cast<VoidFooTy>(&foo);
+
+ using IntFooTy = void (*)(int *);
+ auto C = reinterpret_cast<IntFooTy>(foo);
+ auto CAmp = reinterpret_cast<IntFooTy>(&foo);
+
+ using CharFooTy = void (*)(void *);
+ auto D = reinterpret_cast<CharFooTy>(foo);
+ auto DAmp = reinterpret_cast<CharFooTy>(&foo);
+}
+
+void testItCStyle() {
+ auto A = (VoidFnTy)foo;
+ auto AAmp = (VoidFnTy)&foo;
+
+ using VoidFooTy = void (*)(void *);
+ auto B = (VoidFooTy)foo;
+ auto BAmp = (VoidFooTy)&foo;
+
+ using IntFooTy = void (*)(int *);
+ auto C = (IntFooTy)foo;
+ auto CAmp = (IntFooTy)&foo;
+
+ using CharFooTy = void (*)(void *);
+ auto D = (CharFooTy)foo;
+ auto DAmp = (CharFooTy)&foo;
+}
+}
+
+namespace casting_templates {
+template <typename T> void foo(T) {} // expected-note 4 {{candidate function}}
+
+void foo(int *c) __attribute__((enable_if(c, ""))); //expected-note 4 {{candidate function}}
+void foo(char *c) __attribute__((enable_if(c, ""))); //expected-note 4 {{candidate function}}
+
+void testIt() {
+ using IntFooTy = void (*)(int *);
+ auto A = reinterpret_cast<IntFooTy>(foo); // expected-error{{reinterpret_cast cannot resolve overloaded function 'foo' to type}}
+ auto ARef = reinterpret_cast<IntFooTy>(&foo); // expected-error{{reinterpret_cast cannot resolve overloaded function 'foo' to type}}
+ auto AExplicit = reinterpret_cast<IntFooTy>(foo<int*>);
+
+ using CharFooTy = void (*)(char *);
+ auto B = reinterpret_cast<CharFooTy>(foo); // expected-error{{reinterpret_cast cannot resolve overloaded function 'foo' to type}}
+ auto BRef = reinterpret_cast<CharFooTy>(&foo); // expected-error{{reinterpret_cast cannot resolve overloaded function 'foo' to type}}
+ auto BExplicit = reinterpret_cast<CharFooTy>(foo<char*>);
+}
+
+void testItCStyle() {
+ // constexpr is usable here because all of these should become static_casts.
+ using IntFooTy = void (*)(int *);
+ constexpr auto A = (IntFooTy)foo;
+ constexpr auto ARef = (IntFooTy)&foo;
+ constexpr auto AExplicit = (IntFooTy)foo<int*>;
+
+ using CharFooTy = void (*)(char *);
+ constexpr auto B = (CharFooTy)foo;
+ constexpr auto BRef = (CharFooTy)&foo;
+ constexpr auto BExplicit = (CharFooTy)foo<char*>;
+
+ static_assert(A == ARef && ARef == AExplicit, "");
+ static_assert(B == BRef && BRef == BExplicit, "");
+}
+}
+
+namespace multiple_matches {
+using NoMatchTy = void (*)();
+
+void foo(float *c); //expected-note 4 {{candidate function}}
+void foo(int *c) __attribute__((enable_if(1, ""))); //expected-note 4 {{candidate function}}
+void foo(char *c) __attribute__((enable_if(1, ""))); //expected-note 4 {{candidate function}}
+
+void testIt() {
+ auto A = reinterpret_cast<NoMatchTy>(foo); // expected-error{{reinterpret_cast cannot resolve overloaded function 'foo' to type}}
+ auto ARef = reinterpret_cast<NoMatchTy>(&foo); // expected-error{{reinterpret_cast cannot resolve overloaded function 'foo' to type}}
+
+ auto C = (NoMatchTy)foo; // expected-error{{address of overloaded function 'foo' does not match required type 'void ()'}}
+ auto CRef = (NoMatchTy)&foo; // expected-error{{address of overloaded function 'foo' does not match required type 'void ()'}}
+}
+}
Index: cfe/trunk/test/SemaCXX/unaddressable-functions.cpp
===================================================================
--- cfe/trunk/test/SemaCXX/unaddressable-functions.cpp
+++ cfe/trunk/test/SemaCXX/unaddressable-functions.cpp
@@ -0,0 +1,36 @@
+// RUN: %clang_cc1 -fsyntax-only -verify %s -std=c++14
+
+namespace access_control {
+class Private {
+ void check(int *) __attribute__((enable_if(false, "")));
+ void check(double *) __attribute__((enable_if(true, "")));
+
+ static void checkStatic(int *) __attribute__((enable_if(false, "")));
+ static void checkStatic(double *) __attribute__((enable_if(true, "")));
+};
+
+auto Priv = reinterpret_cast<void (Private::*)(char *)>(&Private::check); // expected-error{{'check' is a private member of 'access_control::Private'}} expected-note@6{{implicitly declared private here}}
+
+auto PrivStatic = reinterpret_cast<void (*)(char *)>(&Private::checkStatic); // expected-error{{'checkStatic' is a private member of 'access_control::Private'}} expected-note@9{{implicitly declared private here}}
+
+class Protected {
+protected:
+ void check(int *) __attribute__((enable_if(false, "")));
+ void check(double *) __attribute__((enable_if(true, "")));
+
+ static void checkStatic(int *) __attribute__((enable_if(false, "")));
+ static void checkStatic(double *) __attribute__((enable_if(true, "")));
+};
+
+auto Prot = reinterpret_cast<void (Protected::*)(char *)>(&Protected::check); // expected-error{{'check' is a protected member of 'access_control::Protected'}} expected-note@19{{declared protected here}}
+
+auto ProtStatic = reinterpret_cast<void (*)(char *)>(&Protected::checkStatic); // expected-error{{'checkStatic' is a protected member of 'access_control::Protected'}} expected-note@22{{declared protected here}}
+}
+
+namespace unavailable {
+// Ensure that we check that the function can be called
+void foo() __attribute__((unavailable("don't call this")));
+void foo(int) __attribute__((enable_if(false, "")));
+
+void *Ptr = reinterpret_cast<void*>(foo); // expected-error{{'foo' is unavailable: don't call this}} expected-note@-3{{explicitly marked unavailable here}}
+}
Index: cfe/trunk/lib/Sema/SemaOverload.cpp
===================================================================
--- cfe/trunk/lib/Sema/SemaOverload.cpp
+++ cfe/trunk/lib/Sema/SemaOverload.cpp
@@ -10419,7 +10419,7 @@
return false;
QualType ResultTy;
- if (Context.hasSameUnqualifiedType(TargetFunctionType,
+ if (Context.hasSameUnqualifiedType(TargetFunctionType,
FunDecl->getType()) ||
S.IsNoReturnConversion(FunDecl->getType(), TargetFunctionType,
ResultTy) ||
@@ -10652,6 +10652,42 @@
}
/// \brief Given an expression that refers to an overloaded function, try to
+/// resolve that function to a single function that can have its address taken.
+/// This will modify `Pair` iff it returns non-null.
+///
+/// This routine can only realistically succeed if all but one candidates in the
+/// overload set for SrcExpr cannot have their addresses taken.
+FunctionDecl *
+Sema::resolveAddressOfOnlyViableOverloadCandidate(Expr *E,
+ DeclAccessPair &Pair) {
+ OverloadExpr::FindResult R = OverloadExpr::find(E);
+ OverloadExpr *Ovl = R.Expression;
+ FunctionDecl *Result = nullptr;
+ DeclAccessPair DAP;
+ // Don't use the AddressOfResolver because we're specifically looking for
+ // cases where we have one overload candidate that lacks
+ // enable_if/pass_object_size/...
+ for (auto I = Ovl->decls_begin(), E = Ovl->decls_end(); I != E; ++I) {
+ auto *FD = dyn_cast<FunctionDecl>(I->getUnderlyingDecl());
+ if (!FD)
+ return nullptr;
+
+ if (!checkAddressOfFunctionIsAvailable(FD))
+ continue;
+
+ // We have more than one result; quit.
+ if (Result)
+ return nullptr;
+ DAP = I.getPair();
+ Result = FD;
+ }
+
+ if (Result)
+ Pair = DAP;
+ return Result;
+}
+
+/// \brief Given an expression that refers to an overloaded function, try to
/// resolve that overloaded function expression down to a single function.
///
/// This routine can only resolve template-ids that refer to a single function
Index: cfe/trunk/lib/Sema/SemaCast.cpp
===================================================================
--- cfe/trunk/lib/Sema/SemaCast.cpp
+++ cfe/trunk/lib/Sema/SemaCast.cpp
@@ -1750,6 +1750,44 @@
}
}
+static bool fixOverloadedReinterpretCastExpr(Sema &Self, QualType DestType,
+ ExprResult &Result) {
+ // We can only fix an overloaded reinterpret_cast if
+ // - it is a template with explicit arguments that resolves to an lvalue
+ // unambiguously, or
+ // - it is the only function in an overload set that may have its address
+ // taken.
+
+ Expr *E = Result.get();
+ // TODO: what if this fails because of DiagnoseUseOfDecl or something
+ // like it?
+ if (Self.ResolveAndFixSingleFunctionTemplateSpecialization(
+ Result,
+ Expr::getValueKindForType(DestType) == VK_RValue // Convert Fun to Ptr
+ ) &&
+ Result.isUsable())
+ return true;
+
+ DeclAccessPair DAP;
+ FunctionDecl *Found = Self.resolveAddressOfOnlyViableOverloadCandidate(E, DAP);
+ if (!Found)
+ return false;
+
+ // It seems that if we encounter a call to a function that is both unavailable
+ // and inaccessible, we'll emit multiple diags for said call. Hence, we run
+ // both checks below unconditionally.
+ Self.DiagnoseUseOfDecl(Found, E->getExprLoc());
+ Self.CheckAddressOfMemberAccess(E, DAP);
+
+ Expr *Fixed = Self.FixOverloadedFunctionReference(E, DAP, Found);
+ if (Fixed->getType()->isFunctionType())
+ Result = Self.DefaultFunctionArrayConversion(Fixed, /*Diagnose=*/false);
+ else
+ Result = Fixed;
+
+ return !Result.isInvalid();
+}
+
static TryCastResult TryReinterpretCast(Sema &Self, ExprResult &SrcExpr,
QualType DestType, bool CStyle,
SourceRange OpRange,
@@ -1761,21 +1799,15 @@
QualType SrcType = SrcExpr.get()->getType();
// Is the source an overloaded name? (i.e. &foo)
- // If so, reinterpret_cast can not help us here (13.4, p1, bullet 5) ...
+ // If so, reinterpret_cast generally can not help us here (13.4, p1, bullet 5)
if (SrcType == Self.Context.OverloadTy) {
- // ... unless foo<int> resolves to an lvalue unambiguously.
- // TODO: what if this fails because of DiagnoseUseOfDecl or something
- // like it?
- ExprResult SingleFunctionExpr = SrcExpr;
- if (Self.ResolveAndFixSingleFunctionTemplateSpecialization(
- SingleFunctionExpr,
- Expr::getValueKindForType(DestType) == VK_RValue // Convert Fun to Ptr
- ) && SingleFunctionExpr.isUsable()) {
- SrcExpr = SingleFunctionExpr;
- SrcType = SrcExpr.get()->getType();
- } else {
+ ExprResult FixedExpr = SrcExpr;
+ if (!fixOverloadedReinterpretCastExpr(Self, DestType, FixedExpr))
return TC_NotApplicable;
- }
+
+ assert(FixedExpr.isUsable() && "Invalid result fixing overloaded expr");
+ SrcExpr = FixedExpr;
+ SrcType = SrcExpr.get()->getType();
}
if (const ReferenceType *DestTypeTmp = DestType->getAs<ReferenceType>()) {
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