[llvm-commits] CVS: llvm-gcc/gcc/llvm-types.c llvm-expand.c

[Chris Lattner]

Changes in directory llvm-gcc/gcc:

llvm-types.c updated: 1.20 -> 1.21
llvm-expand.c updated: 1.97 -> 1.98
---
Log message:

Be less paranoid about structures with holes in them for unions.  This fixes
PR562: http://llvm.cs.uiuc.edu/PR562  and CFrontend/2005-05-10-GlobalUnionInit.c


---
Diffs of the changes:  (+23 -2)

 llvm-expand.c |    3 ++-
 llvm-types.c  |   22 +++++++++++++++++++++-
 2 files changed, 23 insertions(+), 2 deletions(-)


Index: llvm-gcc/gcc/llvm-types.c
diff -u llvm-gcc/gcc/llvm-types.c:1.20 llvm-gcc/gcc/llvm-types.c:1.21
--- llvm-gcc/gcc/llvm-types.c:1.20	Sat Dec  4 15:44:55 2004
+++ llvm-gcc/gcc/llvm-types.c	Tue May 10 17:33:16 2005
@@ -943,6 +943,26 @@
   return TREE_ADDRESSABLE(Type);
 }
 
+/* isStructWithHoles - This function returns true if the specified type is a
+ * struct and if it has inter-element gaps.
+ */
+static isStructWithHoles(llvm_type *Ty) {
+  unsigned i, e;
+  if (Ty->ID != StructTyID) return 0;
+
+  /* Check to see that element i+1 starts at offsetof(i)+sizeof(STy[i]). */
+  for (i = 0, e = Ty->NumElements; i != e-1; ++i)
+    if (Ty->x.Struct.MemberOffsets[i] + llvm_type_get_size(Ty->Elements[i]) !=
+        Ty->x.Struct.MemberOffsets[i+1])
+      return 1;
+
+  /* Check for tail padding. */
+  if (Ty->x.Struct.MemberOffsets[e-1] + llvm_type_get_size(Ty->Elements[e-1]) !=
+      llvm_type_get_size(Ty))
+    return 1;
+  return 0;
+}
+
 /* llvm_type_get_tree_type - Return the LLVM type that corresponds to the
  * specified tree type.  If this is the first time we have seen a structure
  * type, we assign indexes to all of the FIELD_DECLs in it.
@@ -1195,7 +1215,7 @@
      * FIXME: Couldn't there be arrays that have structure types in them?
      * What about alignment?  This preserves size but not necessarily alignment!
      */
-    if (ElementType->ID == StructTyID) {
+    if (isStructWithHoles(ElementType)) {
       assert((MaxSize & 7) == 0 &&
               "Only unions that are multiple of byte size expected!");
       if (MaxSize & 0xF)


Index: llvm-gcc/gcc/llvm-expand.c
diff -u llvm-gcc/gcc/llvm-expand.c:1.97 llvm-gcc/gcc/llvm-expand.c:1.98
--- llvm-gcc/gcc/llvm-expand.c:1.97	Fri May  6 21:16:47 2005
+++ llvm-gcc/gcc/llvm-expand.c	Tue May 10 17:33:16 2005
@@ -3932,7 +3932,8 @@
          *  So, for now, we will simply assert and stay as compile-fail until
          *  we can get the whole thing working.
          */
-        assert ((FieldSizeTree != NULL_TREE) && "Struct/Union member of unknown length!");
+        assert ((FieldSizeTree != NULL_TREE) &&
+                "Struct/Union member of unknown length!");
         FieldSize = TREE_INT_CST_LOW (FieldSizeTree);
         
         assert(FieldIndex && "Structure isn't laid out by LLVM yet!");