Eliminate CXXConditionDeclExpr with extreme prejudice.

All statements that involve conditions can now hold on to a separate
condition declaration (a VarDecl), and will use a DeclRefExpr
referring to that VarDecl for the condition expression. ForStmts now
have such a VarDecl (I'd missed those in previous commits).

Also, since this change reworks the Action interface for
if/while/switch/for, use FullExprArg for the full expressions in those
expressions, to ensure that we're emitting

Note that we are (still) not generating the right cleanups for
condition variables in for statements. That will be a follow-on
commit.

llvm-svn: 89817

1 files changed, 36 insertions, 0 deletions

diff --git a/clang/lib/Sema/SemaDeclCXX.cpp b/clang/lib/Sema/SemaDeclCXX.cpp
index b5419c1c907..1df11731215 100644
--- a/clang/lib/Sema/SemaDeclCXX.cpp
+++ b/clang/lib/Sema/SemaDeclCXX.cpp
@@ -4918,3 +4918,39 @@ void Sema::ActOnCXXExitDeclInitializer(Scope *S, DeclPtrTy Dcl) {
   assert(S->getEntity() == D->getDeclContext() && "Context imbalance!");
   ExitDeclaratorContext(S);
 }
+
+/// ActOnCXXConditionDeclarationExpr - Parsed a condition declaration of a
+/// C++ if/switch/while/for statement.
+/// e.g: "if (int x = f()) {...}"
+Action::DeclResult
+Sema::ActOnCXXConditionDeclaration(Scope *S, Declarator &D) {
+  // C++ 6.4p2:
+  // The declarator shall not specify a function or an array.
+  // The type-specifier-seq shall not contain typedef and shall not declare a
+  // new class or enumeration.
+  assert(D.getDeclSpec().getStorageClassSpec() != DeclSpec::SCS_typedef &&
+         "Parser allowed 'typedef' as storage class of condition decl.");
+  
+  DeclaratorInfo *DInfo = 0;
+  TagDecl *OwnedTag = 0;
+  QualType Ty = GetTypeForDeclarator(D, S, &DInfo, &OwnedTag);
+  
+  if (Ty->isFunctionType()) { // The declarator shall not specify a function...
+                              // We exit without creating a CXXConditionDeclExpr because a FunctionDecl
+                              // would be created and CXXConditionDeclExpr wants a VarDecl.
+    Diag(D.getIdentifierLoc(), diag::err_invalid_use_of_function_type)
+      << D.getSourceRange();
+    return DeclResult();
+  } else if (OwnedTag && OwnedTag->isDefinition()) {
+    // The type-specifier-seq shall not declare a new class or enumeration.
+    Diag(OwnedTag->getLocation(), diag::err_type_defined_in_condition);
+  }
+  
+  DeclPtrTy Dcl = ActOnDeclarator(S, D);
+  if (!Dcl)
+    return DeclResult();
+
+  VarDecl *VD = cast<VarDecl>(Dcl.getAs<Decl>());
+  VD->setDeclaredInCondition(true);
+  return Dcl;
+}