[llvm] r226837 - Document DIExpression.

[Adrian Prantl]

Author: adrian
Date: Thu Jan 22 10:55:24 2015
New Revision: 226837

URL: http://llvm.org/viewvc/llvm-project?rev=226837&view=rev
Log:
Document DIExpression.

Modified:
    llvm/trunk/include/llvm/IR/DebugInfo.h

Modified: llvm/trunk/include/llvm/IR/DebugInfo.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/IR/DebugInfo.h?rev=226837&r1=226836&r2=226837&view=diff
==============================================================================
--- llvm/trunk/include/llvm/IR/DebugInfo.h (original)
+++ llvm/trunk/include/llvm/IR/DebugInfo.h Thu Jan 22 10:55:24 2015
@@ -850,7 +850,13 @@ public:
   void printExtendedName(raw_ostream &OS) const;
 };
 
-/// \brief A complex location expression.
+/// \brief A complex location expression in postfix notation.
+///
+/// This is (almost) a DWARF expression that modifies the location of a
+/// variable or (or the location of a single piece of a variable).
+///
+/// FIXME: Instead of DW_OP_plus taking an argument, this should use DW_OP_const
+/// and have DW_OP_plus consume the topmost elements on the stack.
 class DIExpression : public DIDescriptor {
   friend class DIDescriptor;
   void printInternal(raw_ostream &OS) const;