Refactor instantiation of declarations within a template into a much

cleaner visitor framework.

Added a visitor for declarations, which is quite similar to the
visitor for statatements.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@67104 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 202 insertions, 0 deletions

diff --git a/lib/Sema/SemaTemplateInstantiateDecl.cpp b/lib/Sema/SemaTemplateInstantiateDecl.cpp
new file mode 100644
index 0000000000..906ea25822
--- /dev/null
+++ b/lib/Sema/SemaTemplateInstantiateDecl.cpp
@@ -0,0 +1,202 @@
+//===--- SemaTemplateInstantiateDecl.cpp - C++ Template Decl Instantiation ===/
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//===----------------------------------------------------------------------===/
+//
+//  This file implements C++ template instantiation for declarations.
+//
+//===----------------------------------------------------------------------===/
+#include "Sema.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/AST/DeclTemplate.h"
+#include "clang/AST/DeclVisitor.h"
+#include "clang/AST/Expr.h"
+#include "llvm/Support/Compiler.h"
+
+using namespace clang;
+
+namespace {
+  class VISIBILITY_HIDDEN TemplateDeclInstantiator 
+    : public DeclVisitor<TemplateDeclInstantiator, Decl *> 
+  {
+    Sema &SemaRef;
+    DeclContext *Owner;
+    const TemplateArgument *TemplateArgs;
+    unsigned NumTemplateArgs;
+    
+  public:
+    typedef Sema::OwningExprResult OwningExprResult;
+
+    TemplateDeclInstantiator(Sema &SemaRef, DeclContext *Owner,
+                             const TemplateArgument *TemplateArgs,
+                             unsigned NumTemplateArgs)
+      : SemaRef(SemaRef), Owner(Owner), TemplateArgs(TemplateArgs), 
+        NumTemplateArgs(NumTemplateArgs) { }
+    
+    // FIXME: Once we get closer to completion, replace these
+    // manually-written declarations with automatically-generated ones
+    // from clang/AST/DeclNodes.def.
+    Decl *VisitTypedefDecl(TypedefDecl *D);
+    Decl *VisitFieldDecl(FieldDecl *D);
+    Decl *VisitStaticAssertDecl(StaticAssertDecl *D);
+    Decl *VisitEnumDecl(EnumDecl *D);
+
+    // Base case. FIXME: Remove once we can instantiate everything.
+    Decl *VisitDecl(Decl *) { 
+      return 0;
+    }
+  };
+}
+
+Decl *TemplateDeclInstantiator::VisitTypedefDecl(TypedefDecl *D) {
+  bool Invalid = false;
+  QualType T = D->getUnderlyingType();
+  if (T->isDependentType()) {
+    T = SemaRef.InstantiateType(T, TemplateArgs, NumTemplateArgs,
+                                D->getLocation(),
+                                D->getDeclName());
+    if (T.isNull()) {
+      Invalid = true;
+      T = SemaRef.Context.IntTy;
+    }
+  }
+       
+  // Create the new typedef
+  TypedefDecl *Typedef
+    = TypedefDecl::Create(SemaRef.Context, Owner, D->getLocation(),
+                          D->getIdentifier(), T);
+  if (Invalid)
+    Typedef->setInvalidDecl();
+
+  Owner->addDecl(Typedef);
+  return Typedef;
+}
+
+Decl *TemplateDeclInstantiator::VisitFieldDecl(FieldDecl *D) {
+  bool Invalid = false;
+  QualType T = D->getType();
+  if (T->isDependentType())  {
+    T = SemaRef.InstantiateType(T, TemplateArgs, NumTemplateArgs,
+                                D->getLocation(),
+                                D->getDeclName());
+    if (!T.isNull() && T->isFunctionType()) {
+      // C++ [temp.arg.type]p3:
+      //   If a declaration acquires a function type through a type
+      //   dependent on a template-parameter and this causes a
+      //   declaration that does not use the syntactic form of a
+      //   function declarator to have function type, the program is
+      //   ill-formed.
+      SemaRef.Diag(D->getLocation(), diag::err_field_instantiates_to_function)
+        << T;
+      T = QualType();
+      Invalid = true;
+    }
+  }
+
+  Expr *BitWidth = D->getBitWidth();
+  if (Invalid)
+    BitWidth = 0;
+  else if (BitWidth) {
+    OwningExprResult InstantiatedBitWidth
+      = SemaRef.InstantiateExpr(BitWidth, TemplateArgs, NumTemplateArgs);
+    if (InstantiatedBitWidth.isInvalid()) {
+      Invalid = true;
+      BitWidth = 0;
+    } else
+      BitWidth = (Expr *)InstantiatedBitWidth.release();
+  }
+
+  FieldDecl *Field = SemaRef.CheckFieldDecl(D->getDeclName(), T,
+                                            cast<RecordDecl>(Owner), 
+                                            D->getLocation(),
+                                            D->isMutable(),
+                                            BitWidth,
+                                            D->getAccess(),
+                                            0);
+  if (Field) {
+    if (Invalid)
+      Field->setInvalidDecl();
+    
+    Owner->addDecl(Field);
+  }
+
+  return Field;
+}
+
+Decl *TemplateDeclInstantiator::VisitStaticAssertDecl(StaticAssertDecl *D) {
+  Expr *AssertExpr = D->getAssertExpr();
+      
+  OwningExprResult InstantiatedAssertExpr
+    = SemaRef.InstantiateExpr(AssertExpr, TemplateArgs, NumTemplateArgs);
+  if (InstantiatedAssertExpr.isInvalid())
+    return 0;
+
+  OwningExprResult Message = SemaRef.Clone(D->getMessage());
+  Decl *StaticAssert 
+    = (Decl *)SemaRef.ActOnStaticAssertDeclaration(D->getLocation(), 
+                                                move(InstantiatedAssertExpr),
+                                                   move(Message));
+  return StaticAssert;
+}
+
+Decl *TemplateDeclInstantiator::VisitEnumDecl(EnumDecl *D) {
+  EnumDecl *Enum = EnumDecl::Create(SemaRef.Context, Owner, 
+                                    D->getLocation(), D->getIdentifier(),
+                                    /*PrevDecl=*/0);
+  Owner->addDecl(Enum);
+  Enum->startDefinition();
+
+  llvm::SmallVector<Sema::DeclTy *, 16> Enumerators;
+
+  EnumConstantDecl *LastEnumConst = 0;
+  for (EnumDecl::enumerator_iterator EC = D->enumerator_begin(),
+         ECEnd = D->enumerator_end();
+       EC != ECEnd; ++EC) {
+    // The specified value for the enumerator.
+    OwningExprResult Value = SemaRef.Owned((Expr *)0);
+    if (Expr *UninstValue = EC->getInitExpr())
+      Value = SemaRef.InstantiateExpr(UninstValue, 
+                                      TemplateArgs, NumTemplateArgs);
+
+    // Drop the initial value and continue.
+    bool isInvalid = false;
+    if (Value.isInvalid()) {
+      Value = SemaRef.Owned((Expr *)0);
+      isInvalid = true;
+    }
+
+    EnumConstantDecl *EnumConst 
+      = SemaRef.CheckEnumConstant(Enum, LastEnumConst,
+                                  EC->getLocation(), EC->getIdentifier(),
+                                  move(Value));
+
+    if (isInvalid) {
+      if (EnumConst)
+        EnumConst->setInvalidDecl();
+      Enum->setInvalidDecl();
+    }
+
+    if (EnumConst) {
+      Enum->addDecl(EnumConst);
+      Enumerators.push_back(EnumConst);
+      LastEnumConst = EnumConst;
+    }
+  }
+      
+  SemaRef.ActOnEnumBody(Enum->getLocation(), Enum,
+                        &Enumerators[0], Enumerators.size());
+
+  return Enum;
+}
+
+Decl *Sema::InstantiateDecl(Decl *D, DeclContext *Owner,
+                            const TemplateArgument *TemplateArgs,
+                            unsigned NumTemplateArgs) {
+  TemplateDeclInstantiator Instantiator(*this, Owner, TemplateArgs,
+                                        NumTemplateArgs);
+  return Instantiator.Visit(D);
+}
+