[Concepts] Concept definitions (D40381)

First in a series of patches to land C++2a Concepts support.
This patch adds AST and parsing support for concept-declarations.

llvm-svn: 365699

5 files changed, 52 insertions, 2 deletions

diff --git a/clang/lib/AST/ASTStructuralEquivalence.cpp b/clang/lib/AST/ASTStructuralEquivalence.cpp
index 744b30f8533..bb2e353eeef 100644
--- a/clang/lib/AST/ASTStructuralEquivalence.cpp
+++ b/clang/lib/AST/ASTStructuralEquivalence.cpp
@@ -1513,6 +1513,18 @@ static bool IsStructurallyEquivalent(StructuralEquivalenceContext &Context,
 }
 
 static bool IsStructurallyEquivalent(StructuralEquivalenceContext &Context,
+                                     ConceptDecl *D1,
+                                     ConceptDecl *D2) {
+  // Check template parameters.
+  if (!IsTemplateDeclCommonStructurallyEquivalent(Context, D1, D2))
+    return false;
+
+  // Check the constraint expression.
+  return IsStructurallyEquivalent(Context, D1->getConstraintExpr(),
+                                  D2->getConstraintExpr());
+}
+
+static bool IsStructurallyEquivalent(StructuralEquivalenceContext &Context,
                                      FriendDecl *D1, FriendDecl *D2) {
   if ((D1->getFriendType() && D2->getFriendDecl()) ||
       (D1->getFriendDecl() && D2->getFriendType())) {
@@ -1771,6 +1783,14 @@ bool StructuralEquivalenceContext::CheckKindSpecificEquivalence(
       // Class template/non-class-template mismatch.
       return false;
     }
+  } else if (auto *ConceptDecl1 = dyn_cast<ConceptDecl>(D1)) {
+    if (auto *ConceptDecl2 = dyn_cast<ConceptDecl>(D2)) {
+      if (!::IsStructurallyEquivalent(*this, ConceptDecl1, ConceptDecl2))
+        return false;
+    } else {
+      // Concept/non-concept mismatch.
+      return false;
+    }
   } else if (auto *TTP1 = dyn_cast<TemplateTypeParmDecl>(D1)) {
     if (auto *TTP2 = dyn_cast<TemplateTypeParmDecl>(D2)) {
       if (!::IsStructurallyEquivalent(*this, TTP1, TTP2))
diff --git a/clang/lib/AST/DeclBase.cpp b/clang/lib/AST/DeclBase.cpp
index f5853b49804..fd80e1532eb 100644
--- a/clang/lib/AST/DeclBase.cpp
+++ b/clang/lib/AST/DeclBase.cpp
@@ -710,6 +710,7 @@ unsigned Decl::getIdentifierNamespaceForKind(Kind DeclKind) {
     case Binding:
     case NonTypeTemplateParm:
     case VarTemplate:
+    case Concept:
       // These (C++-only) declarations are found by redeclaration lookup for
       // tag types, so we include them in the tag namespace.
       return IDNS_Ordinary | IDNS_Tag;
diff --git a/clang/lib/AST/DeclPrinter.cpp b/clang/lib/AST/DeclPrinter.cpp
index 73dcdc6854f..f5c69944034 100644
--- a/clang/lib/AST/DeclPrinter.cpp
+++ b/clang/lib/AST/DeclPrinter.cpp
@@ -1123,8 +1123,13 @@ void DeclPrinter::VisitTemplateDecl(const TemplateDecl *D) {
     if (TTP->isParameterPack())
       Out << "...";
     Out << D->getName();
-  } else {
-    Visit(D->getTemplatedDecl());
+  } else if (auto *TD = D->getTemplatedDecl())
+    Visit(TD);
+  else if (const auto *Concept = dyn_cast<ConceptDecl>(D)) {
+    Out << "concept " << Concept->getName() << " = " ;
+    Concept->getConstraintExpr()->printPretty(Out, nullptr, Policy,
+                                              Indentation);
+    Out << ";";
   }
 }
 
diff --git a/clang/lib/AST/DeclTemplate.cpp b/clang/lib/AST/DeclTemplate.cpp
index 3c4cf72f7f5..40c39c845db 100644
--- a/clang/lib/AST/DeclTemplate.cpp
+++ b/clang/lib/AST/DeclTemplate.cpp
@@ -822,6 +822,26 @@ ClassTemplateSpecializationDecl::getSourceRange() const {
 }
 
 //===----------------------------------------------------------------------===//
+// ConceptDecl Implementation
+//===----------------------------------------------------------------------===//
+ConceptDecl *ConceptDecl::Create(ASTContext &C, DeclContext *DC,
+                                 SourceLocation L, DeclarationName Name,
+                                 TemplateParameterList *Params,
+                                 Expr *ConstraintExpr) {
+  AdoptTemplateParameterList(Params, DC);
+  return new (C, DC) ConceptDecl(DC, L, Name, Params, ConstraintExpr);
+}
+
+ConceptDecl *ConceptDecl::CreateDeserialized(ASTContext &C,
+                                             unsigned ID) {
+  ConceptDecl *Result = new (C, ID) ConceptDecl(nullptr, SourceLocation(),
+                                                DeclarationName(),
+                                                nullptr, nullptr);
+
+  return Result;
+}
+
+//===----------------------------------------------------------------------===//
 // ClassTemplatePartialSpecializationDecl Implementation
 //===----------------------------------------------------------------------===//
 void ClassTemplatePartialSpecializationDecl::anchor() {}
diff --git a/clang/lib/AST/TextNodeDumper.cpp b/clang/lib/AST/TextNodeDumper.cpp
index 01bcc22753e..44c2612a721 100644
--- a/clang/lib/AST/TextNodeDumper.cpp
+++ b/clang/lib/AST/TextNodeDumper.cpp
@@ -1936,3 +1936,7 @@ void TextNodeDumper::VisitBlockDecl(const BlockDecl *D) {
   if (D->capturesCXXThis())
     OS << " captures_this";
 }
+
+void TextNodeDumper::VisitConceptDecl(const ConceptDecl *D) {
+  dumpName(D);
+}
\ No newline at end of file