[llvm-commits] [llvm-gcc-4.2] r73730 - /llvm-gcc-4.2/trunk/gcc/llvm-convert.cpp

[Chris Lattner]

Author: lattner
Date: Thu Jun 18 17:54:19 2009
New Revision: 73730

URL: http://llvm.org/viewvc/llvm-project?rev=73730&view=rev
Log:
fix rdar://6983634 - when inserting tail padding to round up an initializer to
the right size, we have to be careful when the max struct alignment will cause the
size-with-alignment to be too big.  In this case, switch the struct to being packed.

This fixes rdar://6983634 and test/FrontendC/2009-06-18-StaticInitTailPadPack.c


Modified:
    llvm-gcc-4.2/trunk/gcc/llvm-convert.cpp

Modified: llvm-gcc-4.2/trunk/gcc/llvm-convert.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm-gcc-4.2/trunk/gcc/llvm-convert.cpp?rev=73730&r1=73729&r2=73730&view=diff

==============================================================================
--- llvm-gcc-4.2/trunk/gcc/llvm-convert.cpp (original)
+++ llvm-gcc-4.2/trunk/gcc/llvm-convert.cpp Thu Jun 18 17:54:19 2009
@@ -7187,6 +7187,21 @@
     if (GCCStructSize - NextFieldByteStart != 1)
       FillTy = ArrayType::get(FillTy, GCCStructSize - NextFieldByteStart);
     ResultElts.push_back(Constant::getNullValue(FillTy));
+    NextFieldByteStart = GCCStructSize;
+  
+    // At this point, we know that our struct should have the right size.
+    // However, if the size of the struct is not a multiple of the largest
+    // element alignment, the rounding could bump up the struct more.  In this
+    // case, we have to convert the struct to being packed.
+    LLVMNaturalSize =
+      TargetData::RoundUpAlignment(NextFieldByteStart, MaxLLVMFieldAlignment);
+
+    // If the alignment will make the struct too big, convert it to being
+    // packed.
+    if (LLVMNaturalSize > GCCStructSize) {
+      assert(!StructIsPacked && "LLVM Struct type overflow!");
+      ConvertToPacked();
+    }
   }
 }