replica
/
hanchenye-llvm-project
2
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

Allow dllimport non-type template arguments in C++17 

Summary:
Fixes PR35772.

Reviewers: rsmith

Differential Revision: https://reviews.llvm.org/D43320

llvm-svn: 332018
This commit is contained in:
Reid Kleckner 2018-05-10 18:57:35 +00:00
parent 175400a801
commit 1a840d29b4
5 changed files with 112 additions and 22 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

7
clang/include/clang/AST/Expr.h
View File

@ -658,6 +658,13 @@ public:
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

57
clang/lib/AST/ExprConstant.cpp
View File

@ -1720,7 +1720,8 @@ static void NoteLValueLocation(EvalInfo &Info, APValue::LValueBase Base) {
/// 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 @@ static bool CheckLValueConstantExpression(EvalInfo &Info, SourceLocation Loc,
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 @@ static bool CheckLValueConstantExpression(EvalInfo &Info, SourceLocation Loc,
// 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 CheckLValueConstantExpression(EvalInfo &Info, SourceLocation Loc,
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 @@ static bool CheckLiteralType(EvalInfo &Info, const Expr *E,
/// 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;
@ -1863,28 +1869,28 @@ static bool CheckConstantExpression(EvalInfo &Info, SourceLocation DiagLoc,
QualType EltTy = Type->castAsArrayTypeUnsafe()->getElementType();
for (unsigned I = 0, N = Value.getArrayInitializedElts(); I != N; ++I) {
if (!CheckConstantExpression(Info, DiagLoc, EltTy,
Value.getArrayInitializedElt(I)))
Value.getArrayInitializedElt(I), Usage))
return false;
}
if (!Value.hasArrayFiller())
return true;
return CheckConstantExpression(Info, DiagLoc, EltTy,
Value.getArrayFiller());
return CheckConstantExpression(Info, DiagLoc, EltTy, Value.getArrayFiller(),
Usage);
}
if (Value.isUnion() && Value.getUnionField()) {
return CheckConstantExpression(Info, DiagLoc,
Value.getUnionField()->getType(),
Value.getUnionValue());
Value.getUnionValue(), Usage);
}
if (Value.isStruct()) {
RecordDecl *RD = Type->castAs<RecordType>()->getDecl();
if (const CXXRecordDecl *CD = dyn_cast<CXXRecordDecl>(RD)) {
unsigned BaseIndex = 0;
for (CXXRecordDecl::base_class_const_iterator I = CD->bases_begin(),
End = CD->bases_end(); I != End; ++I, ++BaseIndex) {
if (!CheckConstantExpression(Info, DiagLoc, I->getType(),
Value.getStructBase(BaseIndex)))
for (const CXXBaseSpecifier &BS : CD->bases()) {
if (!CheckConstantExpression(Info, DiagLoc, BS.getType(),
Value.getStructBase(BaseIndex), Usage))
return false;
++BaseIndex;
}
}
for (const auto *I : RD->fields()) {
@ -1892,7 +1898,8 @@ static bool CheckConstantExpression(EvalInfo &Info, SourceLocation DiagLoc,
continue;
if (!CheckConstantExpression(Info, DiagLoc, I->getType(),
Value.getStructField(I->getFieldIndex())))
Value.getStructField(I->getFieldIndex()),
Usage))
return false;
}
}
@ -1900,11 +1907,11 @@ static bool CheckConstantExpression(EvalInfo &Info, SourceLocation DiagLoc,
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 +10352,25 @@ bool Expr::EvaluateAsLValue(EvalResult &Result, const ASTContext &Ctx) const {
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 {

7
clang/lib/Sema/SemaOverload.cpp
View File

@ -5407,10 +5407,11 @@ static ExprResult CheckConvertedConstantExpression(Sema &S, Expr *From,
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.

62
clang/test/SemaCXX/dllimport-constexpr.cpp Normal file
View File

@ -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();
}

1
clang/test/SemaCXX/dllimport-memptr.cpp
View File

@ -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