[clang] 50b1faf - [Clang] CWG 1394: Incomplete types as parameters of deleted functions
PoYao Chang via cfe-commits
cfe-commits at lists.llvm.org
Mon Apr 11 20:18:07 PDT 2022
Author: PoYao Chang
Date: 2022-04-12T11:10:10+08:00
New Revision: 50b1faf5c188956fb59ea7d9f9d470591771aedb
URL: https://github.com/llvm/llvm-project/commit/50b1faf5c188956fb59ea7d9f9d470591771aedb
DIFF: https://github.com/llvm/llvm-project/commit/50b1faf5c188956fb59ea7d9f9d470591771aedb.diff
LOG: [Clang] CWG 1394: Incomplete types as parameters of deleted functions
According to CWG 1394 and C++20 [dcl.fct.def.general]p2,
Clang should not diagnose incomplete types if function body is "= delete;".
For example:
```
struct Incomplete;
Incomplete f(Incomplete) = delete; // well-formed
```
Also close https://github.com/llvm/llvm-project/issues/52802
Differential Revision: https://reviews.llvm.org/D122981
Added:
clang/test/CXX/dcl.decl/dcl.fct.def/dcl.fct.def.general/p2.cpp
Modified:
clang/docs/ReleaseNotes.rst
clang/include/clang/Sema/Sema.h
clang/lib/Parse/Parser.cpp
clang/lib/Sema/SemaDecl.cpp
clang/lib/Sema/SemaDeclCXX.cpp
clang/www/cxx_dr_status.html
Removed:
################################################################################
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index c53fa0ad7fe01..fbc1edb8e9e2a 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -113,6 +113,10 @@ Bug Fixes
This fixes Issue `Issue 54462 <https://github.com/llvm/llvm-project/issues/54462>`_.
- Statement expressions are now disabled in default arguments in general.
This fixes Issue `Issue 53488 <https://github.com/llvm/llvm-project/issues/53488>`_.
+- According to `CWG 1394 <https://wg21.link/cwg1394>`_ and
+ `C++20 [dcl.fct.def.general]p2 <https://timsong-cpp.github.io/cppwp/n4868/dcl.fct.def#general-2.sentence-3>`_,
+ Clang should not diagnose incomplete types in function definitions if the function body is "= delete;".
+ This fixes Issue `Issue 52802 <https://github.com/llvm/llvm-project/issues/52802>`_.
Improvements to Clang's diagnostics
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
diff --git a/clang/include/clang/Sema/Sema.h b/clang/include/clang/Sema/Sema.h
index e7f417a82003b..e368726d11c66 100644
--- a/clang/include/clang/Sema/Sema.h
+++ b/clang/include/clang/Sema/Sema.h
@@ -2895,6 +2895,18 @@ class Sema final {
void ActOnDocumentableDecl(Decl *D);
void ActOnDocumentableDecls(ArrayRef<Decl *> Group);
+ enum class FnBodyKind {
+ /// C++ [dcl.fct.def.general]p1
+ /// function-body:
+ /// ctor-initializer[opt] compound-statement
+ /// function-try-block
+ Other,
+ /// = default ;
+ Default,
+ /// = delete ;
+ Delete
+ };
+
void ActOnFinishKNRParamDeclarations(Scope *S, Declarator &D,
SourceLocation LocAfterDecls);
void CheckForFunctionRedefinition(
@@ -2902,9 +2914,12 @@ class Sema final {
SkipBodyInfo *SkipBody = nullptr);
Decl *ActOnStartOfFunctionDef(Scope *S, Declarator &D,
MultiTemplateParamsArg TemplateParamLists,
- SkipBodyInfo *SkipBody = nullptr);
+ SkipBodyInfo *SkipBody = nullptr,
+ FnBodyKind BodyKind = FnBodyKind::Other);
Decl *ActOnStartOfFunctionDef(Scope *S, Decl *D,
- SkipBodyInfo *SkipBody = nullptr);
+ SkipBodyInfo *SkipBody = nullptr,
+ FnBodyKind BodyKind = FnBodyKind::Other);
+ void SetFunctionBodyKind(Decl *D, SourceLocation Loc, FnBodyKind BodyKind);
void ActOnStartTrailingRequiresClause(Scope *S, Declarator &D);
ExprResult ActOnFinishTrailingRequiresClause(ExprResult ConstraintExpr);
ExprResult ActOnRequiresClause(ExprResult ConstraintExpr);
diff --git a/clang/lib/Parse/Parser.cpp b/clang/lib/Parse/Parser.cpp
index 9c8892ebc4b84..f754388cdc7c8 100644
--- a/clang/lib/Parse/Parser.cpp
+++ b/clang/lib/Parse/Parser.cpp
@@ -1299,6 +1299,41 @@ Decl *Parser::ParseFunctionDefinition(ParsingDeclarator &D,
ParseScope BodyScope(this, Scope::FnScope | Scope::DeclScope |
Scope::CompoundStmtScope);
+ // Parse function body eagerly if it is either '= delete;' or '= default;' as
+ // ActOnStartOfFunctionDef needs to know whether the function is deleted.
+ Sema::FnBodyKind BodyKind = Sema::FnBodyKind::Other;
+ SourceLocation KWLoc;
+ if (TryConsumeToken(tok::equal)) {
+ assert(getLangOpts().CPlusPlus && "Only C++ function definitions have '='");
+
+ if (TryConsumeToken(tok::kw_delete, KWLoc)) {
+ Diag(KWLoc, getLangOpts().CPlusPlus11
+ ? diag::warn_cxx98_compat_defaulted_deleted_function
+ : diag::ext_defaulted_deleted_function)
+ << 1 /* deleted */;
+ BodyKind = Sema::FnBodyKind::Delete;
+ } else if (TryConsumeToken(tok::kw_default, KWLoc)) {
+ Diag(KWLoc, getLangOpts().CPlusPlus11
+ ? diag::warn_cxx98_compat_defaulted_deleted_function
+ : diag::ext_defaulted_deleted_function)
+ << 0 /* defaulted */;
+ BodyKind = Sema::FnBodyKind::Default;
+ } else {
+ llvm_unreachable("function definition after = not 'delete' or 'default'");
+ }
+
+ if (Tok.is(tok::comma)) {
+ Diag(KWLoc, diag::err_default_delete_in_multiple_declaration)
+ << (BodyKind == Sema::FnBodyKind::Delete);
+ SkipUntil(tok::semi);
+ } else if (ExpectAndConsume(tok::semi, diag::err_expected_after,
+ BodyKind == Sema::FnBodyKind::Delete
+ ? "delete"
+ : "default")) {
+ SkipUntil(tok::semi);
+ }
+ }
+
// Tell the actions module that we have entered a function definition with the
// specified Declarator for the function.
Sema::SkipBodyInfo SkipBody;
@@ -1306,10 +1341,13 @@ Decl *Parser::ParseFunctionDefinition(ParsingDeclarator &D,
TemplateInfo.TemplateParams
? *TemplateInfo.TemplateParams
: MultiTemplateParamsArg(),
- &SkipBody);
+ &SkipBody, BodyKind);
if (SkipBody.ShouldSkip) {
- SkipFunctionBody();
+ // Do NOT enter SkipFunctionBody if we already consumed the tokens.
+ if (BodyKind == Sema::FnBodyKind::Other)
+ SkipFunctionBody();
+
return Res;
}
@@ -1320,6 +1358,13 @@ Decl *Parser::ParseFunctionDefinition(ParsingDeclarator &D,
// safe because we're always the sole owner.
D.getMutableDeclSpec().abort();
+ if (BodyKind != Sema::FnBodyKind::Other) {
+ Actions.SetFunctionBodyKind(Res, KWLoc, BodyKind);
+ Stmt *GeneratedBody = Res ? Res->getBody() : nullptr;
+ Actions.ActOnFinishFunctionBody(Res, GeneratedBody, false);
+ return Res;
+ }
+
// With abbreviated function templates - we need to explicitly add depth to
// account for the implicit template parameter list induced by the template.
if (auto *Template = dyn_cast_or_null<FunctionTemplateDecl>(Res))
@@ -1329,42 +1374,6 @@ Decl *Parser::ParseFunctionDefinition(ParsingDeclarator &D,
// parameter list was specified.
CurTemplateDepthTracker.addDepth(1);
- if (TryConsumeToken(tok::equal)) {
- assert(getLangOpts().CPlusPlus && "Only C++ function definitions have '='");
-
- bool Delete = false;
- SourceLocation KWLoc;
- if (TryConsumeToken(tok::kw_delete, KWLoc)) {
- Diag(KWLoc, getLangOpts().CPlusPlus11
- ? diag::warn_cxx98_compat_defaulted_deleted_function
- : diag::ext_defaulted_deleted_function)
- << 1 /* deleted */;
- Actions.SetDeclDeleted(Res, KWLoc);
- Delete = true;
- } else if (TryConsumeToken(tok::kw_default, KWLoc)) {
- Diag(KWLoc, getLangOpts().CPlusPlus11
- ? diag::warn_cxx98_compat_defaulted_deleted_function
- : diag::ext_defaulted_deleted_function)
- << 0 /* defaulted */;
- Actions.SetDeclDefaulted(Res, KWLoc);
- } else {
- llvm_unreachable("function definition after = not 'delete' or 'default'");
- }
-
- if (Tok.is(tok::comma)) {
- Diag(KWLoc, diag::err_default_delete_in_multiple_declaration)
- << Delete;
- SkipUntil(tok::semi);
- } else if (ExpectAndConsume(tok::semi, diag::err_expected_after,
- Delete ? "delete" : "default")) {
- SkipUntil(tok::semi);
- }
-
- Stmt *GeneratedBody = Res ? Res->getBody() : nullptr;
- Actions.ActOnFinishFunctionBody(Res, GeneratedBody, false);
- return Res;
- }
-
if (SkipFunctionBodies && (!Res || Actions.canSkipFunctionBody(Res)) &&
trySkippingFunctionBody()) {
BodyScope.Exit();
diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index a99b9833b3f53..cd9e6d56a5aee 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -14271,7 +14271,7 @@ void Sema::ActOnFinishKNRParamDeclarations(Scope *S, Declarator &D,
Decl *
Sema::ActOnStartOfFunctionDef(Scope *FnBodyScope, Declarator &D,
MultiTemplateParamsArg TemplateParameterLists,
- SkipBodyInfo *SkipBody) {
+ SkipBodyInfo *SkipBody, FnBodyKind BodyKind) {
assert(getCurFunctionDecl() == nullptr && "Function parsing confused");
assert(D.isFunctionDeclarator() && "Not a function declarator!");
Scope *ParentScope = FnBodyScope->getParent();
@@ -14290,7 +14290,7 @@ Sema::ActOnStartOfFunctionDef(Scope *FnBodyScope, Declarator &D,
D.setFunctionDefinitionKind(FunctionDefinitionKind::Definition);
Decl *DP = HandleDeclarator(ParentScope, D, TemplateParameterLists);
- Decl *Dcl = ActOnStartOfFunctionDef(FnBodyScope, DP, SkipBody);
+ Decl *Dcl = ActOnStartOfFunctionDef(FnBodyScope, DP, SkipBody, BodyKind);
if (!Bases.empty())
ActOnFinishedFunctionDefinitionInOpenMPDeclareVariantScope(Dcl, Bases);
@@ -14466,7 +14466,8 @@ static void RebuildLambdaScopeInfo(CXXMethodDecl *CallOperator,
}
Decl *Sema::ActOnStartOfFunctionDef(Scope *FnBodyScope, Decl *D,
- SkipBodyInfo *SkipBody) {
+ SkipBodyInfo *SkipBody,
+ FnBodyKind BodyKind) {
if (!D) {
// Parsing the function declaration failed in some way. Push on a fake scope
// anyway so we can try to parse the function body.
@@ -14555,11 +14556,11 @@ Decl *Sema::ActOnStartOfFunctionDef(Scope *FnBodyScope, Decl *D,
}
}
- // The return type of a function definition must be complete
- // (C99 6.9.1p3, C++ [dcl.fct]p6).
+ // The return type of a function definition must be complete (C99 6.9.1p3),
+ // unless the function is deleted (C++ specifc, C++ [dcl.fct.def.general]p2)
QualType ResultType = FD->getReturnType();
if (!ResultType->isDependentType() && !ResultType->isVoidType() &&
- !FD->isInvalidDecl() &&
+ !FD->isInvalidDecl() && BodyKind != FnBodyKind::Delete &&
RequireCompleteType(FD->getLocation(), ResultType,
diag::err_func_def_incomplete_result))
FD->setInvalidDecl();
@@ -14568,8 +14569,9 @@ Decl *Sema::ActOnStartOfFunctionDef(Scope *FnBodyScope, Decl *D,
PushDeclContext(FnBodyScope, FD);
// Check the validity of our function parameters
- CheckParmsForFunctionDef(FD->parameters(),
- /*CheckParameterNames=*/true);
+ if (BodyKind != FnBodyKind::Delete)
+ CheckParmsForFunctionDef(FD->parameters(),
+ /*CheckParameterNames=*/true);
// Add non-parameter declarations already in the function to the current
// scope.
diff --git a/clang/lib/Sema/SemaDeclCXX.cpp b/clang/lib/Sema/SemaDeclCXX.cpp
index 12db7c8595446..4d3a4ba019adf 100644
--- a/clang/lib/Sema/SemaDeclCXX.cpp
+++ b/clang/lib/Sema/SemaDeclCXX.cpp
@@ -17379,6 +17379,21 @@ void Sema::DiagnoseReturnInConstructorExceptionHandler(CXXTryStmt *TryBlock) {
}
}
+void Sema::SetFunctionBodyKind(Decl *D, SourceLocation Loc,
+ FnBodyKind BodyKind) {
+ switch (BodyKind) {
+ case FnBodyKind::Delete:
+ SetDeclDeleted(D, Loc);
+ break;
+ case FnBodyKind::Default:
+ SetDeclDefaulted(D, Loc);
+ break;
+ case FnBodyKind::Other:
+ llvm_unreachable(
+ "Parsed function body should be '= delete;' or '= default;'");
+ }
+}
+
bool Sema::CheckOverridingFunctionAttributes(const CXXMethodDecl *New,
const CXXMethodDecl *Old) {
const auto *NewFT = New->getType()->castAs<FunctionProtoType>();
diff --git a/clang/test/CXX/dcl.decl/dcl.fct.def/dcl.fct.def.general/p2.cpp b/clang/test/CXX/dcl.decl/dcl.fct.def/dcl.fct.def.general/p2.cpp
new file mode 100644
index 0000000000000..e42d75377daea
--- /dev/null
+++ b/clang/test/CXX/dcl.decl/dcl.fct.def/dcl.fct.def.general/p2.cpp
@@ -0,0 +1,6 @@
+// RUN: %clang_cc1 -fsyntax-only -verify %s
+
+struct Incomplete; // expected-note 2{{forward declaration of 'Incomplete'}}
+Incomplete f(Incomplete) = delete; // well-formed
+Incomplete g(Incomplete) {} // expected-error{{incomplete result type 'Incomplete' in function definition}}\
+// expected-error{{variable has incomplete type 'Incomplete'}}
diff --git a/clang/www/cxx_dr_status.html b/clang/www/cxx_dr_status.html
index ef131b9a71e67..e193d37c09598 100755
--- a/clang/www/cxx_dr_status.html
+++ b/clang/www/cxx_dr_status.html
@@ -8178,7 +8178,7 @@ <h2 id="cxxdr">C++ defect report implementation status</h2>
<td><a href="https://wg21.link/cwg1394">1394</a></td>
<td>CD3</td>
<td>Incomplete types as parameters of deleted functions</td>
- <td class="none" align="center">Unknown</td>
+ <td class="unreleased" align="center">Clang 15</td>
</tr>
<tr id="1395">
<td><a href="https://wg21.link/cwg1395">1395</a></td>
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