erichkeane created this revision.
erichkeane added reviewers: rnk, lebedev.ri, aaron.ballman.
Herald added subscribers: cfe-commits, arphaman.
Herald added a project: clang.
In response to https://bugs.llvm.org/show_bug.cgi?id=33235, it became
clear that the current mechanism of hacking through checks for the
exception specification of a function gets confused really quickly when
there are alternate exception specifiers.
This patch introduces EST_NoThrow, which is the equivilent of
EST_noexcept when caused by EST_noThrow. The existing implementation is
left in place to cover functions with no FunctionProtoType.
Repository:
rC Clang
https://reviews.llvm.org/D62435
Files:
clang/include/clang-c/Index.h
clang/include/clang/AST/Decl.h
clang/include/clang/AST/Type.h
clang/include/clang/Basic/ExceptionSpecificationType.h
clang/include/clang/Sema/DeclSpec.h
clang/lib/AST/ASTContext.cpp
clang/lib/AST/JSONNodeDumper.cpp
clang/lib/AST/Type.cpp
clang/lib/Sema/SemaDeclAttr.cpp
clang/lib/Sema/SemaDeclCXX.cpp
clang/lib/Sema/SemaExprCXX.cpp
clang/lib/Sema/SemaType.cpp
clang/test/SemaCXX/nothrow-vs-exception-specs.cpp
clang/tools/libclang/CXType.cpp
Index: clang/tools/libclang/CXType.cpp
===================================================================
--- clang/tools/libclang/CXType.cpp
+++ clang/tools/libclang/CXType.cpp
@@ -742,6 +742,8 @@
return CXCursor_ExceptionSpecificationKind_MSAny;
case EST_BasicNoexcept:
return CXCursor_ExceptionSpecificationKind_BasicNoexcept;
+ case EST_NoThrow:
+ return CXCursor_ExceptionSpecificationKind_NoThrow;
case EST_NoexceptFalse:
case EST_NoexceptTrue:
case EST_DependentNoexcept:
Index: clang/test/SemaCXX/nothrow-vs-exception-specs.cpp
===================================================================
--- /dev/null
+++ clang/test/SemaCXX/nothrow-vs-exception-specs.cpp
@@ -0,0 +1,44 @@
+// RUN: %clang_cc1 %s -fcxx-exceptions -fsyntax-only -Wexceptions -verify -std=c++14
+// RUN: %clang_cc1 %s -fcxx-exceptions -fsyntax-only -Wexceptions -verify -std=c++17 -DCPP17
+
+__attribute__((nothrow)) void f1();
+static_assert(noexcept(f1()), "");
+void f1() noexcept;
+// expected-error@+2 {{exception specification in declaration does not match previous declaration}}
+// expected-note@-2 {{previous declaration is here}}
+void f1() noexcept(false);
+
+__attribute__((nothrow)) void f2();
+static_assert(noexcept(f2()), "");
+// expected-error@+2 {{exception specification in declaration does not match previous declaration}}
+// expected-note@-3 {{previous declaration is here}}
+void f2() noexcept(false);
+
+void f3() __attribute__((nothrow));
+static_assert(noexcept(f3()), "");
+void f3() noexcept;
+// expected-error@+2 {{exception specification in declaration does not match previous declaration}}
+// expected-note@-2 {{previous declaration is here}}
+void f3() noexcept(false);
+
+// Still noexcept due to throw()
+__attribute__((nothrow)) void f4() throw();
+static_assert(noexcept(f4()), "");
+
+// Still noexcept due to noexcept
+__attribute__((nothrow)) void f5() noexcept;
+static_assert(noexcept(f5()), "");
+
+// Still noexcept due to noexcept(true)
+__attribute__((nothrow)) void f6() noexcept(true);
+static_assert(noexcept(f6()), "");
+
+#ifndef CPP17
+// Doesn't override C++ implementation.
+__attribute__((nothrow)) void f7() throw(int);
+static_assert(!noexcept(f7()), "");
+#endif
+
+// Doesn't override C++ implementation.
+__attribute__((nothrow)) void f8() noexcept(false);
+static_assert(!noexcept(f8()), "");
Index: clang/lib/Sema/SemaType.cpp
===================================================================
--- clang/lib/Sema/SemaType.cpp
+++ clang/lib/Sema/SemaType.cpp
@@ -130,6 +130,7 @@
case ParsedAttr::AT_Regparm: \
case ParsedAttr::AT_AnyX86NoCallerSavedRegisters: \
case ParsedAttr::AT_AnyX86NoCfCheck: \
+ case ParsedAttr::AT_NoThrow: \
CALLING_CONV_ATTRS_CASELIST
// Microsoft-specific type qualifiers.
@@ -4516,7 +4517,7 @@
// If the function declarator has a prototype (i.e. it is not () and
// does not have a K&R-style identifier list), then the arguments are part
// of the type, otherwise the argument list is ().
- const DeclaratorChunk::FunctionTypeInfo &FTI = DeclType.Fun;
+ DeclaratorChunk::FunctionTypeInfo &FTI = DeclType.Fun;
IsQualifiedFunction =
FTI.hasMethodTypeQualifiers() || FTI.hasRefQualifier();
@@ -6945,6 +6946,38 @@
return true;
}
+ if (attr.getKind() == ParsedAttr::AT_NoThrow) {
+ if (S.CheckAttrNoArgs(attr))
+ return true;
+
+ // Delay if this is not a function type.
+ if (!unwrapped.isFunctionType())
+ return false;
+
+ // Otherwise we can process right away.
+ auto *Proto = unwrapped.get()->getAs<FunctionProtoType>();
+
+ // In the case where this is a FunctionNoProtoType instead of a
+ // FunctionProtoType, let the existing NoThrowAttr implementation do its
+ // thing.
+ if (!Proto)
+ return false;
+
+ attr.setUsedAsTypeAttr();
+
+ // MSVC Ignores nothrow for exception specification if it is in conflict.
+ if (Proto->hasExceptionSpec())
+ return true;
+
+ type = unwrapped.wrap(
+ S, S.Context
+ .getFunctionTypeWithExceptionSpec(
+ QualType{Proto, 0},
+ FunctionProtoType::ExceptionSpecInfo{EST_NoThrow})
+ ->getAs<FunctionType>());
+ return true;
+ }
+
// Delay if the type didn't work out to a function.
if (!unwrapped.isFunctionType()) return false;
Index: clang/lib/Sema/SemaExprCXX.cpp
===================================================================
--- clang/lib/Sema/SemaExprCXX.cpp
+++ clang/lib/Sema/SemaExprCXX.cpp
@@ -6064,6 +6064,8 @@
if (EST2 == EST_BasicNoexcept) return ESI1;
if (EST1 == EST_NoexceptTrue) return ESI2;
if (EST2 == EST_NoexceptTrue) return ESI1;
+ if (EST1 == EST_NoThrow) return ESI2;
+ if (EST2 == EST_NoThrow) return ESI1;
// If we're left with value-dependent computed noexcept expressions, we're
// stuck. Before C++17, we can just drop the exception specification entirely,
@@ -6086,6 +6088,7 @@
case EST_DependentNoexcept:
case EST_NoexceptFalse:
case EST_NoexceptTrue:
+ case EST_NoThrow:
llvm_unreachable("handled above");
case EST_Dynamic: {
Index: clang/lib/Sema/SemaDeclCXX.cpp
===================================================================
--- clang/lib/Sema/SemaDeclCXX.cpp
+++ clang/lib/Sema/SemaDeclCXX.cpp
@@ -192,6 +192,7 @@
// If this function has a basic noexcept, it doesn't affect the outcome.
case EST_BasicNoexcept:
case EST_NoexceptTrue:
+ case EST_NoThrow:
return;
// If we're still at noexcept(true) and there's a throw() callee,
// change to that specification.
@@ -15457,6 +15458,7 @@
case EST_Uninstantiated:
case EST_Unevaluated:
case EST_BasicNoexcept:
+ case EST_NoThrow:
case EST_DynamicNone:
case EST_MSAny:
case EST_None:
Index: clang/lib/Sema/SemaDeclAttr.cpp
===================================================================
--- clang/lib/Sema/SemaDeclAttr.cpp
+++ clang/lib/Sema/SemaDeclAttr.cpp
@@ -6853,7 +6853,8 @@
handleNoCfCheckAttr(S, D, AL);
break;
case ParsedAttr::AT_NoThrow:
- handleSimpleAttribute<NoThrowAttr>(S, D, AL);
+ if (!AL.isUsedAsTypeAttr())
+ handleSimpleAttribute<NoThrowAttr>(S, D, AL);
break;
case ParsedAttr::AT_CUDAShared:
handleSharedAttr(S, D, AL);
Index: clang/lib/AST/Type.cpp
===================================================================
--- clang/lib/AST/Type.cpp
+++ clang/lib/AST/Type.cpp
@@ -3077,6 +3077,7 @@
case EST_DynamicNone:
case EST_BasicNoexcept:
case EST_NoexceptTrue:
+ case EST_NoThrow:
return CT_Cannot;
case EST_None:
Index: clang/lib/AST/JSONNodeDumper.cpp
===================================================================
--- clang/lib/AST/JSONNodeDumper.cpp
+++ clang/lib/AST/JSONNodeDumper.cpp
@@ -464,7 +464,9 @@
//JOS.attributeWithCall("exceptionSpecExpr",
// [this, E]() { Visit(E.ExceptionSpec.NoexceptExpr); });
break;
-
+ case EST_NoThrow:
+ JOS.attribute("exceptionSpec", "nothrow");
+ break;
// FIXME: I cannot find a way to trigger these cases while dumping the AST. I
// suspect you can only run into them when executing an AST dump from within
// the debugger, which is not a use case we worry about for the JSON dumping
Index: clang/lib/AST/ASTContext.cpp
===================================================================
--- clang/lib/AST/ASTContext.cpp
+++ clang/lib/AST/ASTContext.cpp
@@ -3742,7 +3742,10 @@
break;
}
- case EST_DynamicNone: case EST_BasicNoexcept: case EST_NoexceptTrue:
+ case EST_DynamicNone:
+ case EST_BasicNoexcept:
+ case EST_NoexceptTrue:
+ case EST_NoThrow:
CanonicalEPI.ExceptionSpec.Type = EST_BasicNoexcept;
break;
Index: clang/include/clang/Sema/DeclSpec.h
===================================================================
--- clang/include/clang/Sema/DeclSpec.h
+++ clang/include/clang/Sema/DeclSpec.h
@@ -1544,6 +1544,12 @@
const ParsedAttributesView &getAttrs() const { return AttrList; }
ParsedAttributesView &getAttrs() { return AttrList; }
+ bool hasAttr(ParsedAttr::Kind Kind) const {
+ return llvm::find_if(getAttrs(), [Kind](const ParsedAttr &P) {
+ return P.getKind() == Kind;
+ }) != getAttrs().end();
+ }
+
/// Return a DeclaratorChunk for a pointer.
static DeclaratorChunk getPointer(unsigned TypeQuals, SourceLocation Loc,
SourceLocation ConstQualLoc,
Index: clang/include/clang/Basic/ExceptionSpecificationType.h
===================================================================
--- clang/include/clang/Basic/ExceptionSpecificationType.h
+++ clang/include/clang/Basic/ExceptionSpecificationType.h
@@ -22,6 +22,7 @@
EST_DynamicNone, ///< throw()
EST_Dynamic, ///< throw(T1, T2)
EST_MSAny, ///< Microsoft throw(...) extension
+ EST_NoThrow, ///< Microsoft declspec(nothrow) extension
EST_BasicNoexcept, ///< noexcept
EST_DependentNoexcept,///< noexcept(expression), value-dependent
EST_NoexceptFalse, ///< noexcept(expression), evals to 'false'
@@ -41,7 +42,8 @@
}
inline bool isNoexceptExceptionSpec(ExceptionSpecificationType ESpecType) {
- return ESpecType == EST_BasicNoexcept || isComputedNoexcept(ESpecType);
+ return ESpecType == EST_BasicNoexcept || ESpecType == EST_NoThrow ||
+ isComputedNoexcept(ESpecType);
}
inline bool isUnresolvedExceptionSpec(ExceptionSpecificationType ESpecType) {
Index: clang/include/clang/AST/Type.h
===================================================================
--- clang/include/clang/AST/Type.h
+++ clang/include/clang/AST/Type.h
@@ -3855,6 +3855,7 @@
case EST_MSAny:
case EST_BasicNoexcept:
case EST_Unparsed:
+ case EST_NoThrow:
return {0, 0, 0};
case EST_Dynamic:
Index: clang/include/clang/AST/Decl.h
===================================================================
--- clang/include/clang/AST/Decl.h
+++ clang/include/clang/AST/Decl.h
@@ -2330,6 +2330,14 @@
return T->castAs<FunctionType>()->getReturnType();
}
+ /// Gets the ExceptionSpecificationType as declared.
+ ExceptionSpecificationType getExceptionSpecType() const {
+ auto *TSI = getTypeSourceInfo();
+ QualType T = TSI ? TSI->getType() : getType();
+ const auto *FPT = T->getAs<FunctionProtoType>();
+ return FPT ? FPT->getExceptionSpecType() : EST_None;
+ }
+
/// Attempt to compute an informative source range covering the
/// function exception specification, if any.
SourceRange getExceptionSpecSourceRange() const;
Index: clang/include/clang-c/Index.h
===================================================================
--- clang/include/clang-c/Index.h
+++ clang/include/clang-c/Index.h
@@ -199,6 +199,11 @@
CXCursor_ExceptionSpecificationKind_MSAny,
/**
+ * The cursor has a declspec(nothrow) exception specification.
+ */
+ CXCursor_ExceptionSpecificationKind_NoThrow,
+
+ /**
* The cursor has exception specification basic noexcept.
*/
CXCursor_ExceptionSpecificationKind_BasicNoexcept,
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