rnk updated this revision to Diff 146039.
rnk added a comment.
- getting closer
https://reviews.llvm.org/D43320
Files:
clang/include/clang/AST/Expr.h
clang/lib/AST/ExprConstant.cpp
clang/lib/Sema/SemaOverload.cpp
clang/test/SemaCXX/dllimport-constexpr.cpp
clang/test/SemaCXX/dllimport-memptr.cpp
Index: clang/test/SemaCXX/dllimport-memptr.cpp
===================================================================
--- clang/test/SemaCXX/dllimport-memptr.cpp
+++ clang/test/SemaCXX/dllimport-memptr.cpp
@@ -1,4 +1,5 @@
// RUN: %clang_cc1 -triple x86_64-windows-msvc -fms-extensions -verify -std=c++11 %s
+// RUN: %clang_cc1 -triple x86_64-windows-msvc -fms-extensions -verify -std=c++17 %s
// expected-no-diagnostics
Index: clang/test/SemaCXX/dllimport-constexpr.cpp
===================================================================
--- /dev/null
+++ clang/test/SemaCXX/dllimport-constexpr.cpp
@@ -0,0 +1,62 @@
+// RUN: %clang_cc1 -std=c++14 %s -verify -fms-extensions -triple x86_64-windows-msvc
+// RUN: %clang_cc1 -std=c++17 %s -verify -fms-extensions -triple x86_64-windows-msvc
+
+__declspec(dllimport) void imported_func();
+__declspec(dllimport) int imported_int;
+struct Foo {
+ void __declspec(dllimport) imported_method();
+};
+
+// Instantiation is OK.
+template <void (*FP)()> struct TemplateFnPtr {
+ static void getit() { FP(); }
+};
+template <void (&FP)()> struct TemplateFnRef {
+ static void getit() { FP(); }
+};
+void instantiate1() {
+ TemplateFnPtr<&imported_func>::getit();
+ TemplateFnRef<imported_func>::getit();
+}
+
+// Check variable template instantiation.
+template <int *GI> struct TemplateIntPtr {
+ static int getit() { return *GI; }
+};
+template <int &GI> struct TemplateIntRef {
+ static int getit() { return GI; }
+};
+int instantiate2() {
+ int r = 0;
+ r += TemplateIntPtr<&imported_int>::getit();
+ r += TemplateIntRef<imported_int>::getit();
+ return r;
+}
+
+// Member pointer instantiation.
+template <void (Foo::*MP)()> struct TemplateMemPtr { };
+TemplateMemPtr<&Foo::imported_method> instantiate_mp;
+
+// constexpr initialization doesn't work for dllimport things.
+// expected-error@+1{{must be initialized by a constant expression}}
+constexpr void (*constexpr_import_func)() = &imported_func;
+// expected-error@+1{{must be initialized by a constant expression}}
+constexpr int *constexpr_import_int = &imported_int;
+// expected-error@+1{{must be initialized by a constant expression}}
+constexpr void (Foo::*constexpr_memptr)() = &Foo::imported_method;
+
+// We make dynamic initializers for 'const' globals, but not constexpr ones.
+void (*const const_import_func)() = &imported_func;
+int *const const_import_int = &imported_int;
+void (Foo::*const const_memptr)() = &Foo::imported_method;
+
+// Check that using a non-type template parameter for constexpr global
+// initialization is correctly diagnosed during template instantiation.
+template <void (*FP)()> struct StaticConstexpr {
+ // expected-error@+1{{must be initialized by a constant expression}}
+ static constexpr void (*g_fp)() = FP;
+};
+void instantiate3() {
+ // expected-note@+1 {{requested here}}
+ StaticConstexpr<imported_func>::g_fp();
+}
Index: clang/lib/Sema/SemaOverload.cpp
===================================================================
--- clang/lib/Sema/SemaOverload.cpp
+++ clang/lib/Sema/SemaOverload.cpp
@@ -5407,10 +5407,11 @@
SmallVector<PartialDiagnosticAt, 8> Notes;
Expr::EvalResult Eval;
Eval.Diag = &Notes;
+ Expr::ConstExprUsage Usage = CCE == Sema::CCEK_TemplateArg
+ ? Expr::EvaluateForMangling
+ : Expr::EvaluateForCodeGen;
- if ((T->isReferenceType()
- ? !Result.get()->EvaluateAsLValue(Eval, S.Context)
- : !Result.get()->EvaluateAsRValue(Eval, S.Context)) ||
+ if (!Result.get()->EvaluateAsConstantExpr(Eval, Usage, S.Context) ||
(RequireInt && !Eval.Val.isInt())) {
// The expression can't be folded, so we can't keep it at this position in
// the AST.
Index: clang/lib/AST/ExprConstant.cpp
===================================================================
--- clang/lib/AST/ExprConstant.cpp
+++ clang/lib/AST/ExprConstant.cpp
@@ -1720,7 +1720,8 @@
/// value for an address or reference constant expression. Return true if we
/// can fold this expression, whether or not it's a constant expression.
static bool CheckLValueConstantExpression(EvalInfo &Info, SourceLocation Loc,
- QualType Type, const LValue &LVal) {
+ QualType Type, const LValue &LVal,
+ Expr::ConstExprUsage Usage) {
bool IsReferenceType = Type->isReferenceType();
APValue::LValueBase Base = LVal.getLValueBase();
@@ -1753,7 +1754,7 @@
return false;
// A dllimport variable never acts like a constant.
- if (Var->hasAttr<DLLImportAttr>())
+ if (Usage == Expr::EvaluateForCodeGen && Var->hasAttr<DLLImportAttr>())
return false;
}
if (const auto *FD = dyn_cast<const FunctionDecl>(VD)) {
@@ -1767,7 +1768,8 @@
// The C language has no notion of ODR; furthermore, it has no notion of
// dynamic initialization. This means that we are permitted to
// perform initialization with the address of the thunk.
- if (Info.getLangOpts().CPlusPlus && FD->hasAttr<DLLImportAttr>())
+ if (Info.getLangOpts().CPlusPlus && Usage == Expr::EvaluateForCodeGen &&
+ FD->hasAttr<DLLImportAttr>())
return false;
}
}
@@ -1800,12 +1802,14 @@
static bool CheckMemberPointerConstantExpression(EvalInfo &Info,
SourceLocation Loc,
QualType Type,
- const APValue &Value) {
+ const APValue &Value,
+ Expr::ConstExprUsage Usage) {
const ValueDecl *Member = Value.getMemberPointerDecl();
const auto *FD = dyn_cast_or_null<CXXMethodDecl>(Member);
if (!FD)
return true;
- return FD->isVirtual() || !FD->hasAttr<DLLImportAttr>();
+ return Usage == Expr::EvaluateForMangling || FD->isVirtual() ||
+ !FD->hasAttr<DLLImportAttr>();
}
/// Check that this core constant expression is of literal type, and if not,
@@ -1843,8 +1847,10 @@
/// Check that this core constant expression value is a valid value for a
/// constant expression. If not, report an appropriate diagnostic. Does not
/// check that the expression is of literal type.
-static bool CheckConstantExpression(EvalInfo &Info, SourceLocation DiagLoc,
- QualType Type, const APValue &Value) {
+static bool
+CheckConstantExpression(EvalInfo &Info, SourceLocation DiagLoc, QualType Type,
+ const APValue &Value,
+ Expr::ConstExprUsage Usage = Expr::EvaluateForCodeGen) {
if (Value.isUninit()) {
Info.FFDiag(DiagLoc, diag::note_constexpr_uninitialized)
<< true << Type;
@@ -1900,11 +1906,11 @@
if (Value.isLValue()) {
LValue LVal;
LVal.setFrom(Info.Ctx, Value);
- return CheckLValueConstantExpression(Info, DiagLoc, Type, LVal);
+ return CheckLValueConstantExpression(Info, DiagLoc, Type, LVal, Usage);
}
if (Value.isMemberPointer())
- return CheckMemberPointerConstantExpression(Info, DiagLoc, Type, Value);
+ return CheckMemberPointerConstantExpression(Info, DiagLoc, Type, Value, Usage);
// Everything else is fine.
return true;
@@ -10345,13 +10351,25 @@
LValue LV;
if (!EvaluateLValue(this, LV, Info) || Result.HasSideEffects ||
!CheckLValueConstantExpression(Info, getExprLoc(),
- Ctx.getLValueReferenceType(getType()), LV))
+ Ctx.getLValueReferenceType(getType()), LV,
+ Expr::EvaluateForCodeGen))
return false;
LV.moveInto(Result.Val);
return true;
}
+bool Expr::EvaluateAsConstantExpr(EvalResult &Result, ConstExprUsage Usage,
+ const ASTContext &Ctx) const {
+ EvalInfo::EvaluationMode EM = EvalInfo::EM_ConstantExpression;
+ EvalInfo Info(Ctx, Result, EM);
+ if (!::Evaluate(Result.Val, Info, this))
+ return false;
+
+ return CheckConstantExpression(Info, getExprLoc(), getType(), Result.Val,
+ Usage);
+}
+
bool Expr::EvaluateAsInitializer(APValue &Value, const ASTContext &Ctx,
const VarDecl *VD,
SmallVectorImpl<PartialDiagnosticAt> &Notes) const {
Index: clang/include/clang/AST/Expr.h
===================================================================
--- clang/include/clang/AST/Expr.h
+++ clang/include/clang/AST/Expr.h
@@ -658,6 +658,13 @@
ArrayRef<const Expr*> Args,
const Expr *This = nullptr) const;
+ /// Indicates how the constant expression will be used.
+ enum ConstExprUsage { EvaluateForCodeGen, EvaluateForMangling };
+
+ /// Evaluate an expression that is required to be a constant expression.
+ bool EvaluateAsConstantExpr(EvalResult &Result, ConstExprUsage Usage,
+ const ASTContext &Ctx) const;
+
/// If the current Expr is a pointer, this will try to statically
/// determine the number of bytes available where the pointer is pointing.
/// Returns true if all of the above holds and we were able to figure out the
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