From 8732bbec1ec96d78c9d79df3c24aae686a7b7a91 Mon Sep 17 00:00:00 2001
From: Benjamin Kramer <benny.kra@googlemail.com>
Date: Tue, 31 Oct 2017 19:40:03 +0000
Subject: [PATCH] [DWARF] Now that Optional is standard layout, put it into an
 union instead of splatting it.

No functionality change intended.

llvm-svn: 317028
---
 .../llvm/DebugInfo/DWARF/DWARFAbbreviationDeclaration.h   | 15 ++++-----------
 llvm/lib/DebugInfo/DWARF/DWARFAbbreviationDeclaration.cpp |  4 ++--
 2 files changed, 6 insertions(+), 13 deletions(-)

diff --git a/llvm/include/llvm/DebugInfo/DWARF/DWARFAbbreviationDeclaration.h b/llvm/include/llvm/DebugInfo/DWARF/DWARFAbbreviationDeclaration.h
index 84b2339..de49be5 100644
--- a/llvm/include/llvm/DebugInfo/DWARF/DWARFAbbreviationDeclaration.h
+++ b/llvm/include/llvm/DebugInfo/DWARF/DWARFAbbreviationDeclaration.h
@@ -33,11 +33,8 @@ public:
       assert(isImplicitConst());
     }
     AttributeSpec(dwarf::Attribute A, dwarf::Form F, Optional<uint8_t> ByteSize)
-        : Attr(A), Form(F) {
+        : Attr(A), Form(F), ByteSize(ByteSize) {
       assert(!isImplicitConst());
-      this->ByteSize.HasByteSize = ByteSize.hasValue();
-      if (this->ByteSize.HasByteSize)
-        this->ByteSize.ByteSize = *ByteSize;
     }
 
     dwarf::Attribute Attr;
@@ -48,21 +45,17 @@ public:
     /// attributes and as value for implicit_const ones, indicated by
     /// Form == DW_FORM_implicit_const.
     /// The following cases are distinguished:
-    /// * Form != DW_FORM_implicit_const and HasByteSize is true:
+    /// * Form != DW_FORM_implicit_const and ByteSize has a value:
     ///     ByteSize contains the fixed size in bytes for the Form in this
     ///     object.
-    /// * Form != DW_FORM_implicit_const and HasByteSize is false:
+    /// * Form != DW_FORM_implicit_const and ByteSize is None:
     ///     byte size of Form either varies according to the DWARFUnit
     ///     that it is contained in or the value size varies and must be
     ///     decoded from the debug information in order to determine its size.
     /// * Form == DW_FORM_implicit_const:
     ///     Value contains value for the implicit_const attribute.
-    struct ByteSizeStorage {
-      bool HasByteSize;
-      uint8_t ByteSize;
-    };
     union {
-      ByteSizeStorage ByteSize;
+      Optional<uint8_t> ByteSize;
       int64_t Value;
     };
 
diff --git a/llvm/lib/DebugInfo/DWARF/DWARFAbbreviationDeclaration.cpp b/llvm/lib/DebugInfo/DWARF/DWARFAbbreviationDeclaration.cpp
index a88dcfc..1fc54d20 100644
--- a/llvm/lib/DebugInfo/DWARF/DWARFAbbreviationDeclaration.cpp
+++ b/llvm/lib/DebugInfo/DWARF/DWARFAbbreviationDeclaration.cpp
@@ -214,8 +214,8 @@ Optional<int64_t> DWARFAbbreviationDeclaration::AttributeSpec::getByteSize(
     const DWARFUnit &U) const {
   if (isImplicitConst())
     return 0;
-  if (ByteSize.HasByteSize)
-    return ByteSize.ByteSize;
+  if (ByteSize)
+    return *ByteSize;
   Optional<int64_t> S;
   auto FixedByteSize =
       DWARFFormValue::getFixedByteSize(Form, U.getFormParams());
-- 
2.7.4