[Concepts] Constrained partial specializations and function overloads.

Added support for constraint satisfaction checking and partial ordering of constraints in constrained partial specialization and function template overloads.
Re-commit after fixing another crash (added regression test).

Differential Revision: https://reviews.llvm.org/D41910

1 files changed, 65 insertions, 14 deletions

diff --git a/clang/lib/AST/DeclTemplate.cpp b/clang/lib/AST/DeclTemplate.cpp
index 7e013c6c54d..23734396b76 100644..100755
--- a/clang/lib/AST/DeclTemplate.cpp
+++ b/clang/lib/AST/DeclTemplate.cpp
@@ -231,15 +231,16 @@ void RedeclarableTemplateDecl::loadLazySpecializationsImpl() const {
   }
 }
 
-template<class EntryType>
+template<class EntryType, typename... ProfileArguments>
 typename RedeclarableTemplateDecl::SpecEntryTraits<EntryType>::DeclType *
 RedeclarableTemplateDecl::findSpecializationImpl(
-    llvm::FoldingSetVector<EntryType> &Specs, ArrayRef<TemplateArgument> Args,
-    void *&InsertPos) {
+    llvm::FoldingSetVector<EntryType> &Specs, void *&InsertPos,
+    ProfileArguments&&... ProfileArgs) {
   using SETraits = SpecEntryTraits<EntryType>;
 
   llvm::FoldingSetNodeID ID;
-  EntryType::Profile(ID, Args, getASTContext());
+  EntryType::Profile(ID, std::forward<ProfileArguments>(ProfileArgs)...,
+                     getASTContext());
   EntryType *Entry = Specs.FindNodeOrInsertPos(ID, InsertPos);
   return Entry ? SETraits::getDecl(Entry)->getMostRecentDecl() : nullptr;
 }
@@ -254,8 +255,8 @@ void RedeclarableTemplateDecl::addSpecializationImpl(
 #ifndef NDEBUG
     void *CorrectInsertPos;
     assert(!findSpecializationImpl(Specializations,
-                                   SETraits::getTemplateArgs(Entry),
-                                   CorrectInsertPos) &&
+                                   CorrectInsertPos,
+                                   SETraits::getTemplateArgs(Entry)) &&
            InsertPos == CorrectInsertPos &&
            "given incorrect InsertPos for specialization");
 #endif
@@ -312,7 +313,7 @@ FunctionTemplateDecl::getSpecializations() const {
 FunctionDecl *
 FunctionTemplateDecl::findSpecialization(ArrayRef<TemplateArgument> Args,
                                          void *&InsertPos) {
-  return findSpecializationImpl(getSpecializations(), Args, InsertPos);
+  return findSpecializationImpl(getSpecializations(), InsertPos, Args);
 }
 
 void FunctionTemplateDecl::addSpecialization(
@@ -418,7 +419,7 @@ ClassTemplateDecl::newCommon(ASTContext &C) const {
 ClassTemplateSpecializationDecl *
 ClassTemplateDecl::findSpecialization(ArrayRef<TemplateArgument> Args,
                                       void *&InsertPos) {
-  return findSpecializationImpl(getSpecializations(), Args, InsertPos);
+  return findSpecializationImpl(getSpecializations(), InsertPos, Args);
 }
 
 void ClassTemplateDecl::AddSpecialization(ClassTemplateSpecializationDecl *D,
@@ -427,9 +428,48 @@ void ClassTemplateDecl::AddSpecialization(ClassTemplateSpecializationDecl *D,
 }
 
 ClassTemplatePartialSpecializationDecl *
-ClassTemplateDecl::findPartialSpecialization(ArrayRef<TemplateArgument> Args,
-                                             void *&InsertPos) {
-  return findSpecializationImpl(getPartialSpecializations(), Args, InsertPos);
+ClassTemplateDecl::findPartialSpecialization(
+    ArrayRef<TemplateArgument> Args,
+    TemplateParameterList *TPL, void *&InsertPos) {
+  return findSpecializationImpl(getPartialSpecializations(), InsertPos, Args,
+                                TPL);
+}
+
+static void ProfileTemplateParameterList(ASTContext &C,
+    llvm::FoldingSetNodeID &ID, const TemplateParameterList *TPL) {
+  const Expr *RC = TPL->getRequiresClause();
+  ID.AddBoolean(RC != nullptr);
+  if (RC)
+    RC->Profile(ID, C, /*Canonical=*/true);
+  ID.AddInteger(TPL->size());
+  for (NamedDecl *D : *TPL) {
+    if (const auto *NTTP = dyn_cast<NonTypeTemplateParmDecl>(D)) {
+      ID.AddInteger(0);
+      ID.AddBoolean(NTTP->isParameterPack());
+      NTTP->getType().getCanonicalType().Profile(ID);
+      continue;
+    }
+    if (const auto *TTP = dyn_cast<TemplateTypeParmDecl>(D)) {
+      ID.AddInteger(1);
+      ID.AddBoolean(TTP->isParameterPack());
+      // TODO: Concepts: profile type-constraints.
+      continue;
+    }
+    const auto *TTP = cast<TemplateTemplateParmDecl>(D);
+    ID.AddInteger(2);
+    ID.AddBoolean(TTP->isParameterPack());
+    ProfileTemplateParameterList(C, ID, TTP->getTemplateParameters());
+  }
+}
+
+void
+ClassTemplatePartialSpecializationDecl::Profile(llvm::FoldingSetNodeID &ID,
+    ArrayRef<TemplateArgument> TemplateArgs, TemplateParameterList *TPL,
+    ASTContext &Context) {
+  ID.AddInteger(TemplateArgs.size());
+  for (const TemplateArgument &TemplateArg : TemplateArgs)
+    TemplateArg.Profile(ID, Context);
+  ProfileTemplateParameterList(Context, ID, TPL);
 }
 
 void ClassTemplateDecl::AddPartialSpecialization(
@@ -1035,7 +1075,7 @@ VarTemplateDecl::newCommon(ASTContext &C) const {
 VarTemplateSpecializationDecl *
 VarTemplateDecl::findSpecialization(ArrayRef<TemplateArgument> Args,
                                     void *&InsertPos) {
-  return findSpecializationImpl(getSpecializations(), Args, InsertPos);
+  return findSpecializationImpl(getSpecializations(), InsertPos, Args);
 }
 
 void VarTemplateDecl::AddSpecialization(VarTemplateSpecializationDecl *D,
@@ -1045,8 +1085,19 @@ void VarTemplateDecl::AddSpecialization(VarTemplateSpecializationDecl *D,
 
 VarTemplatePartialSpecializationDecl *
 VarTemplateDecl::findPartialSpecialization(ArrayRef<TemplateArgument> Args,
-                                           void *&InsertPos) {
-  return findSpecializationImpl(getPartialSpecializations(), Args, InsertPos);
+     TemplateParameterList *TPL, void *&InsertPos) {
+  return findSpecializationImpl(getPartialSpecializations(), InsertPos, Args,
+                                TPL);
+}
+
+void
+VarTemplatePartialSpecializationDecl::Profile(llvm::FoldingSetNodeID &ID,
+    ArrayRef<TemplateArgument> TemplateArgs, TemplateParameterList *TPL,
+    ASTContext &Context) {
+  ID.AddInteger(TemplateArgs.size());
+  for (const TemplateArgument &TemplateArg : TemplateArgs)
+    TemplateArg.Profile(ID, Context);
+  ProfileTemplateParameterList(Context, ID, TPL);
 }
 
 void VarTemplateDecl::AddPartialSpecialization(