From 93b122d3c484a8451024d6947be0f4037f86def0 Mon Sep 17 00:00:00 2001
From: Chris Lattner <sabre@nondot.org>
Date: Tue, 16 Mar 2010 21:25:55 +0000
Subject: reapply r98656 unmodified, which exposed the asmprinter not handling
 constant unions.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@98680 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Target/TargetData.cpp | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

(limited to 'lib/Target/TargetData.cpp')

diff --git a/lib/Target/TargetData.cpp b/lib/Target/TargetData.cpp
index 9a168087ae..643b397746 100644
--- a/lib/Target/TargetData.cpp
+++ b/lib/Target/TargetData.cpp
@@ -460,6 +460,15 @@ uint64_t TargetData::getTypeSizeInBits(const Type *Ty) const {
   case Type::StructTyID:
     // Get the layout annotation... which is lazily created on demand.
     return getStructLayout(cast<StructType>(Ty))->getSizeInBits();
+  case Type::UnionTyID: {
+    const UnionType *UnTy = cast<UnionType>(Ty);
+    uint64_t Size = 0;
+    for (UnionType::element_iterator i = UnTy->element_begin(),
+             e = UnTy->element_end(); i != e; ++i) {
+      Size = std::max(Size, getTypeSizeInBits(*i));
+    }
+    return Size;
+  }
   case Type::IntegerTyID:
     return cast<IntegerType>(Ty)->getBitWidth();
   case Type::VoidTyID:
@@ -516,6 +525,17 @@ unsigned char TargetData::getAlignment(const Type *Ty, bool abi_or_pref) const {
     unsigned Align = getAlignmentInfo(AGGREGATE_ALIGN, 0, abi_or_pref, Ty);
     return std::max(Align, (unsigned)Layout->getAlignment());
   }
+  case Type::UnionTyID: {
+    const UnionType *UnTy = cast<UnionType>(Ty);
+    unsigned Align = 1;
+
+    // Unions need the maximum alignment of all their entries
+    for (UnionType::element_iterator i = UnTy->element_begin(), 
+             e = UnTy->element_end(); i != e; ++i) {
+      Align = std::max(Align, (unsigned)getAlignment(*i, abi_or_pref));
+    }
+    return Align;
+  }
   case Type::IntegerTyID:
   case Type::VoidTyID:
     AlignType = INTEGER_ALIGN;
@@ -600,6 +620,11 @@ uint64_t TargetData::getIndexedOffset(const Type *ptrTy, Value* const* Indices,
 
       // Update Ty to refer to current element
       Ty = STy->getElementType(FieldNo);
+    } else if (const UnionType *UnTy = dyn_cast<UnionType>(*TI)) {
+        unsigned FieldNo = cast<ConstantInt>(Indices[CurIDX])->getZExtValue();
+
+        // Offset into union is canonically 0, but type changes
+        Ty = UnTy->getElementType(FieldNo);
     } else {
       // Update Ty to refer to current element
       Ty = cast<SequentialType>(Ty)->getElementType();
-- 
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