[cfe-commits] r77205 - in /cfe/trunk: lib/CodeGen/CodeGenTypes.cpp test/CodeGenCXX/class-layout.cpp

[Anders Carlsson]

Author: andersca
Date: Mon Jul 27 12:10:54 2009
New Revision: 77205

URL: http://llvm.org/viewvc/llvm-project?rev=77205&view=rev
Log:
Use the CGRecordLayoutBuilder even if there are no fields, because in C++ an empty class will have a padding byte.

Added:
    cfe/trunk/test/CodeGenCXX/class-layout.cpp
Modified:
    cfe/trunk/lib/CodeGen/CodeGenTypes.cpp

Modified: cfe/trunk/lib/CodeGen/CodeGenTypes.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CodeGenTypes.cpp?rev=77205&r1=77204&r2=77205&view=diff

==============================================================================
--- cfe/trunk/lib/CodeGen/CodeGenTypes.cpp (original)
+++ cfe/trunk/lib/CodeGen/CodeGenTypes.cpp Mon Jul 27 12:10:54 2009
@@ -453,36 +453,27 @@
   const llvm::Type *ResultType;
   const RecordDecl *RD = cast<const RecordDecl>(TD);
 
-  // There isn't any extra information for empty structures/unions.
-  if (RD->field_empty()) {
-    ResultType = llvm::StructType::get(std::vector<const llvm::Type*>());
-  } else {
-    // Layout fields.
-    CGRecordLayout *Layout = 
-      CGRecordLayoutBuilder::ComputeLayout(*this, RD);
+  // Layout fields.
+  CGRecordLayout *Layout = 
+    CGRecordLayoutBuilder::ComputeLayout(*this, RD);
     
-    if (!Layout) {
-      // Layout fields.
-      RecordOrganizer RO(*this, *RD);
-
-      if (TD->isStruct() || TD->isClass())
-        RO.layoutStructFields(Context.getASTRecordLayout(RD));
-      else {
-        assert(TD->isUnion() && "unknown tag decl kind!");
-        RO.layoutUnionFields(Context.getASTRecordLayout(RD));
-      }
-      
-      Layout = new CGRecordLayout(RO.getLLVMType(), 
-                                  RO.getPaddingFields());
+  if (!Layout) {
+    // Layout fields.
+    RecordOrganizer RO(*this, *RD);
+
+    if (TD->isStruct() || TD->isClass())
+      RO.layoutStructFields(Context.getASTRecordLayout(RD));
+    else {
+      assert(TD->isUnion() && "unknown tag decl kind!");
+      RO.layoutUnionFields(Context.getASTRecordLayout(RD));
     }
-    
-    // Get llvm::StructType.
-    const Type *Key = 
-      Context.getTagDeclType(const_cast<TagDecl*>(TD)).getTypePtr();
-    
-    CGRecordLayouts[Key] = Layout;
-    ResultType = Layout->getLLVMType();
+      
+    Layout = new CGRecordLayout(RO.getLLVMType(), 
+                                RO.getPaddingFields());
   }
+    
+  CGRecordLayouts[Key] = Layout;
+  ResultType = Layout->getLLVMType();
   
   // Refine our Opaque type to ResultType.  This can invalidate ResultType, so
   // make sure to read the result out of the holder.

Added: cfe/trunk/test/CodeGenCXX/class-layout.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGenCXX/class-layout.cpp?rev=77205&view=auto

==============================================================================
--- cfe/trunk/test/CodeGenCXX/class-layout.cpp (added)
+++ cfe/trunk/test/CodeGenCXX/class-layout.cpp Mon Jul 27 12:10:54 2009
@@ -0,0 +1,5 @@
+// RUN: clang-cc %s -emit-llvm -o %t &&
+
+// An extra byte shoudl be allocated for an empty class.
+// RUN: grep '%.truct.A = type { i8 }' %t
+struct A { } a;