Implement basic support for the use of variadic templates and blocks

together. In particular:
  - Handle the use of captured parameter pack names within blocks
  (BlockDeclRefExpr understands parameter packs now)
  - Handle the declaration and expansion of parameter packs within a block's
  parameter list, e.g., ^(Args ...args) { ... })
  - Handle instantiation of blocks where the return type was not
  explicitly specified. (unrelated, but necessary for my tests).

Together, these fixes should make blocks and variadic templates work
reasonably well together. Note that BlockDeclRefExpr is still broken
w.r.t. its computation of type and value dependence, which will still
cause problems for blocks in templates.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@123849 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/include/clang/AST/Expr.h b/include/clang/AST/Expr.h
index 3bcbf3661aef9881ec5d376a097759fa022bbe86..46fda21fc0c3273ee8bdd1a1ee44c3ae7a5a4743 100644 (file)
--- a/include/clang/AST/Expr.h
+++ b/include/clang/AST/Expr.h
@@ -3572,15 +3572,9 @@ class BlockDeclRefExpr : public Expr {
   bool ConstQualAdded : 1;
   Stmt *CopyConstructorVal;
 public:
-  // FIXME: Fix type/value dependence!
-  // FIXME: Variadic templates.
   BlockDeclRefExpr(ValueDecl *d, QualType t, ExprValueKind VK,
                    SourceLocation l, bool ByRef, bool constAdded = false,
-                   Stmt *copyConstructorVal = 0)
-    : Expr(BlockDeclRefExprClass, t, VK, OK_Ordinary,
-           (!t.isNull() && t->isDependentType()), false, false),
-    D(d), Loc(l), IsByRef(ByRef),
-    ConstQualAdded(constAdded),  CopyConstructorVal(copyConstructorVal) {}
+                   Stmt *copyConstructorVal = 0);
 
   // \brief Build an empty reference to a declared variable in a
   // block.

diff --git a/lib/AST/Expr.cpp b/lib/AST/Expr.cpp
index 4afed433a3c4260a61b8346545a3d477ad4fab7a..9dc790256e78f2445e6d1a49782dcfa7a1b76687 100644 (file)
--- a/lib/AST/Expr.cpp
+++ b/lib/AST/Expr.cpp
@@ -2932,6 +2932,18 @@ Stmt::child_iterator ObjCMessageExpr::child_end() {
 }
 
 // Blocks
+BlockDeclRefExpr::BlockDeclRefExpr(ValueDecl *d, QualType t, ExprValueKind VK,
+                                   SourceLocation l, bool ByRef, 
+                                   bool constAdded, Stmt *copyConstructorVal)
+  : Expr(BlockDeclRefExprClass, t, VK, OK_Ordinary,
+         (!t.isNull() && t->isDependentType()), false,
+         d->isParameterPack()),
+    D(d), Loc(l), IsByRef(ByRef),
+    ConstQualAdded(constAdded),  CopyConstructorVal(copyConstructorVal) 
+{
+  // FIXME: Compute type/value dependence.
+}
+
 Stmt::child_iterator BlockExpr::child_begin() { return child_iterator(); }
 Stmt::child_iterator BlockExpr::child_end() { return child_iterator(); }
 

diff --git a/lib/Sema/SemaTemplateVariadic.cpp b/lib/Sema/SemaTemplateVariadic.cpp
index 38a777efb17fb534d26544c672237eef83868167..3f76d9f6e31963e9a2ae1df28b571909d55b29b7 100644 (file)
--- a/lib/Sema/SemaTemplateVariadic.cpp
+++ b/lib/Sema/SemaTemplateVariadic.cpp
@@ -64,7 +64,7 @@ namespace {
       return true;
     }
 
-    /// \brief Record occurrences of (FIXME: function and) non-type template
+    /// \brief Record occurrences of function and non-type template
     /// parameter packs in an expression.
     bool VisitDeclRefExpr(DeclRefExpr *E) {
       if (E->getDecl()->isParameterPack())
@@ -73,6 +73,15 @@ namespace {
       return true;
     }
     
+    // \brief Record occurrences of function and non-type template parameter
+    // packs in a block-captured expression.
+    bool VisitBlockDeclRefExpr(BlockDeclRefExpr *E) {
+      if (E->getDecl()->isParameterPack())
+        Unexpanded.push_back(std::make_pair(E->getDecl(), E->getLocation()));
+      
+      return true;
+    }
+    
     /// \brief Record occurrences of template template parameter packs.
     bool TraverseTemplateName(TemplateName Template) {
       if (TemplateTemplateParmDecl *TTP 

diff --git a/lib/Sema/TreeTransform.h b/lib/Sema/TreeTransform.h
index ebc34d0f3536c9acc0e58892dc6bde8a7fcd870f..1cb24e70bf62dfdbaacd119dd9fdcc99a930823c 100644 (file)
--- a/lib/Sema/TreeTransform.h
+++ b/lib/Sema/TreeTransform.h
@@ -7122,16 +7122,13 @@ TreeTransform<Derived>::TransformBlockExpr(BlockExpr *E) {
   llvm::SmallVector<QualType, 4> ParamTypes;
   
   // Parameter substitution.
-  // FIXME: Variadic templates
-  const BlockDecl *BD = E->getBlockDecl();
-  for (BlockDecl::param_const_iterator P = BD->param_begin(),
-       EN = BD->param_end(); P != EN; ++P) {
-    ParmVarDecl *OldParm = (*P);
-    ParmVarDecl *NewParm = getDerived().TransformFunctionTypeParam(OldParm,
-                                                   llvm::Optional<unsigned>());
-    Params.push_back(NewParm);
-    ParamTypes.push_back(NewParm->getType());
-  }
+  BlockDecl *BD = E->getBlockDecl();
+  if (getDerived().TransformFunctionTypeParams(E->getLocStart(), 
+                                               BD->param_begin(),
+                                               BD->param_size(), 0, ParamTypes,
+                                               &Params))
+    return true;
+  
   
   const FunctionType *BExprFunctionType = E->getFunctionType();
   QualType BExprResultType = BExprFunctionType->getResultType();
@@ -7141,6 +7138,19 @@ TreeTransform<Derived>::TransformBlockExpr(BlockExpr *E) {
     else if (BExprResultType != SemaRef.Context.DependentTy)
       CurBlock->ReturnType = getDerived().TransformType(BExprResultType);
   }
+  
+  // If the return type has not been determined yet, leave it as a dependent
+  // type; it'll get set when we process the body.
+  if (CurBlock->ReturnType.isNull())
+    CurBlock->ReturnType = getSema().Context.DependentTy;
+
+  // Don't allow returning a objc interface by value.
+  if (CurBlock->ReturnType->isObjCObjectType()) {
+    getSema().Diag(E->getLocStart(), 
+                   diag::err_object_cannot_be_passed_returned_by_value) 
+      << 0 << CurBlock->ReturnType;
+    return ExprError();
+  }
 
   QualType FunctionType = getDerived().RebuildFunctionProtoType(
                                                         CurBlock->ReturnType,
@@ -7154,7 +7164,13 @@ TreeTransform<Derived>::TransformBlockExpr(BlockExpr *E) {
   // Set the parameters on the block decl.
   if (!Params.empty())
     CurBlock->TheDecl->setParams(Params.data(), Params.size());
-    
+  
+  // If the return type wasn't explicitly set, it will have been marked as a 
+  // dependent type (DependentTy); clear out the return type setting so 
+  // we will deduce the return type when type-checking the block's body.
+  if (CurBlock->ReturnType == getSema().Context.DependentTy)
+    CurBlock->ReturnType = QualType();
+  
   // Transform the body
   StmtResult Body = getDerived().TransformStmt(E->getBody());
   if (Body.isInvalid())

diff --git a/test/CXX/temp/temp.decls/temp.variadic/ext-blocks.cpp b/test/CXX/temp/temp.decls/temp.variadic/ext-blocks.cpp
new file mode 100644 (file)
index 0000000..62cf429
--- /dev/null
+++ b/test/CXX/temp/temp.decls/temp.variadic/ext-blocks.cpp
@@ -0,0 +1,39 @@
+// RUN: %clang_cc1 -std=c++0x -fblocks -fsyntax-only -verify %s
+
+// Tests the use of blocks with variadic templates.
+template<typename ...Args>
+int f0(Args ...args) {
+  return ^ {
+    return sizeof...(Args);
+  }() + ^ {
+    return sizeof...(args);
+  }();
+}
+
+template<typename ...Args>
+int f1(Args ...args) {
+  return ^ {
+    return f0(args...);
+  }();
+}
+
+template int f0(int, float, double);
+template int f1(const char*, int, float, double);
+
+template<typename ...Args>
+int f2(Args ...args) {
+  return ^(Args ...block_args) {
+    return f1(block_args...);
+  }(args + 0 ...);
+}
+
+template int f2(const char*, int, float, double);
+
+template<typename ...Args>
+int f3(Args ...args) {
+  return ^(Args *...block_args) {
+    return f1(block_args...);
+  }(&args...);
+}
+
+template int f3(const char*, int, float, double);