[cfe-commits] r105161 - in /cfe/trunk: lib/AST/RecordLayoutBuilder.cpp test/SemaCXX/class-layout.cpp

[Anders Carlsson]

Author: andersca
Date: Sun May 30 01:52:33 2010
New Revision: 105161

URL: http://llvm.org/viewvc/llvm-project?rev=105161&view=rev
Log:
Turn on the new empty base subobject tracking code. It's a bit faster than the previous code. However, it still has quadratic performance, something which I intend to fix shortly in a subsequent patch.

Modified:
    cfe/trunk/lib/AST/RecordLayoutBuilder.cpp
    cfe/trunk/test/SemaCXX/class-layout.cpp

Modified: cfe/trunk/lib/AST/RecordLayoutBuilder.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/AST/RecordLayoutBuilder.cpp?rev=105161&r1=105160&r2=105161&view=diff
==============================================================================
--- cfe/trunk/lib/AST/RecordLayoutBuilder.cpp (original)
+++ cfe/trunk/lib/AST/RecordLayoutBuilder.cpp Sun May 30 01:52:33 2010
@@ -1014,11 +1014,7 @@
 
   // If we have an empty base class, try to place it at offset 0.
   if (Base->Class->isEmpty() &&
-      EmptySubobjects->CanPlaceBaseAtOffset(Base, 0) &&
-      canPlaceRecordAtOffset(Base->Class, 0, /*CheckVBases=*/false)) {
-    // We were able to place the class at offset 0.
-    UpdateEmptyClassOffsets(Base->Class, 0, /*UpdateVBases=*/false);
-
+      EmptySubobjects->CanPlaceBaseAtOffset(Base, 0)) {
     Size = std::max(Size, Layout.getSize());
 
     return 0;
@@ -1030,13 +1026,8 @@
   uint64_t Offset = llvm::RoundUpToAlignment(DataSize, BaseAlign);
 
   // Try to place the base.
-  while (true) {
-    if (EmptySubobjects->CanPlaceBaseAtOffset(Base, Offset) &&
-        canPlaceRecordAtOffset(Base->Class, Offset, /*CheckVBases=*/false))
-      break;
-
+  while (!EmptySubobjects->CanPlaceBaseAtOffset(Base, Offset))
     Offset += BaseAlign;
-  }
 
   if (!Base->Class->isEmpty()) {
     // Update the data size.
@@ -1478,17 +1469,12 @@
   // Round up the current record size to the field's alignment boundary.
   FieldOffset = llvm::RoundUpToAlignment(FieldOffset, FieldAlign);
 
-  if (!IsUnion) {
-    while (true) {
-      // Check if we can place the field at this offset.
-      if (canPlaceFieldAtOffset(D, FieldOffset))
-        break;
-
+  if (!IsUnion && EmptySubobjects) {
+    // Check if we can place the field at this offset.
+    while (!EmptySubobjects->CanPlaceFieldAtOffset(D, FieldOffset)) {
       // We couldn't place the field at the offset. Try again at a new offset.
       FieldOffset += FieldAlign;
     }
-
-    UpdateEmptyClassOffsets(D, FieldOffset);
   }
 
   // Place this field at the current location.

Modified: cfe/trunk/test/SemaCXX/class-layout.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/class-layout.cpp?rev=105161&r1=105160&r2=105161&view=diff
==============================================================================
--- cfe/trunk/test/SemaCXX/class-layout.cpp (original)
+++ cfe/trunk/test/SemaCXX/class-layout.cpp Sun May 30 01:52:33 2010
@@ -84,4 +84,21 @@
 struct G : virtual E, F { };
 
 SA(0, sizeof(G) == 24);
+
+}
+
+namespace Test2 {
+
+// Test that this somewhat complex class structure is laid out correctly.
+struct A { };
+struct B : A { virtual void b(); };
+struct C : virtual B { };
+struct D : virtual A { };
+struct E : virtual B, D { };
+struct F : E, virtual C { };
+struct G : virtual F, A { };
+struct H { G g; };
+
+SA(0, sizeof(H) == 24);
+
 }