[llvm] r174952 - Have the bitcode writer and reader handle the new attribute references.

[Bill Wendling]

Author: void
Date: Tue Feb 12 02:13:50 2013
New Revision: 174952

URL: http://llvm.org/viewvc/llvm-project?rev=174952&view=rev
Log:
Have the bitcode writer and reader handle the new attribute references.

The bitcode writer emits a reference to the attribute group that the object at
the given index refers to. The bitcode reader is modified to read this in and
map it back to the attribute group.

Modified:
    llvm/trunk/lib/Bitcode/Reader/BitcodeReader.cpp
    llvm/trunk/lib/Bitcode/Writer/BitcodeWriter.cpp

Modified: llvm/trunk/lib/Bitcode/Reader/BitcodeReader.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Bitcode/Reader/BitcodeReader.cpp?rev=174952&r1=174951&r2=174952&view=diff
==============================================================================
--- llvm/trunk/lib/Bitcode/Reader/BitcodeReader.cpp (original)
+++ llvm/trunk/lib/Bitcode/Reader/BitcodeReader.cpp Tue Feb 12 02:13:50 2013
@@ -494,6 +494,14 @@ bool BitcodeReader::ParseAttributeBlock(
       Attrs.clear();
       break;
     }
+    case bitc::PARAMATTR_CODE_ENTRY: { // ENTRY: [attrgrp0, attrgrp1, ...]
+      for (unsigned i = 0, e = Record.size(); i != e; ++i)
+        Attrs.push_back(MAttributeGroups[Record[i]]);
+
+      MAttributes.push_back(AttributeSet::get(Context, Attrs));
+      Attrs.clear();
+      break;
+    }
     }
   }
 }

Modified: llvm/trunk/lib/Bitcode/Writer/BitcodeWriter.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Bitcode/Writer/BitcodeWriter.cpp?rev=174952&r1=174951&r2=174952&view=diff
==============================================================================
--- llvm/trunk/lib/Bitcode/Writer/BitcodeWriter.cpp (original)
+++ llvm/trunk/lib/Bitcode/Writer/BitcodeWriter.cpp Tue Feb 12 02:13:50 2013
@@ -209,30 +209,6 @@ static void WriteAttributeGroupTable(con
   Stream.ExitBlock();
 }
 
-/// \brief This returns an integer containing an encoding of all the LLVM
-/// attributes found in the given attribute bitset.  Any change to this encoding
-/// is a breaking change to bitcode compatibility.
-/// N.B. This should be used only by the bitcode writer!
-static uint64_t encodeLLVMAttributesForBitcode(AttributeSet Attrs,
-                                               unsigned Index) {
-  // FIXME: Remove in 4.0!
-
-  // FIXME: It doesn't make sense to store the alignment information as an
-  // expanded out value, we should store it as a log2 value.  However, we can't
-  // just change that here without breaking bitcode compatibility.  If this ever
-  // becomes a problem in practice, we should introduce new tag numbers in the
-  // bitcode file and have those tags use a more efficiently encoded alignment
-  // field.
-
-  // Store the alignment in the bitcode as a 16-bit raw value instead of a 5-bit
-  // log2 encoded value. Shift the bits above the alignment up by 11 bits.
-  uint64_t EncodedAttrs = Attrs.Raw(Index) & 0xffff;
-  if (Attrs.hasAttribute(Index, Attribute::Alignment))
-    EncodedAttrs |= Attrs.getParamAlignment(Index) << 16;
-  EncodedAttrs |= (Attrs.Raw(Index) & (0xfffffULL << 21)) << 11;
-  return EncodedAttrs;
-}
-
 static void WriteAttributeTable(const ValueEnumerator &VE,
                                 BitstreamWriter &Stream) {
   const std::vector<AttributeSet> &Attrs = VE.getAttributes();
@@ -240,19 +216,13 @@ static void WriteAttributeTable(const Va
 
   Stream.EnterSubblock(bitc::PARAMATTR_BLOCK_ID, 3);
 
-  // FIXME: Remove this! It no longer works with the current attributes classes.
-
   SmallVector<uint64_t, 64> Record;
   for (unsigned i = 0, e = Attrs.size(); i != e; ++i) {
     const AttributeSet &A = Attrs[i];
-    for (unsigned i = 0, e = A.getNumSlots(); i != e; ++i) {
-      unsigned Index = A.getSlotIndex(i);
-      Record.push_back(Index);
-      Record.push_back(encodeLLVMAttributesForBitcode(A.getSlotAttributes(i),
-                                                      Index));
-    }
+    for (unsigned i = 0, e = A.getNumSlots(); i != e; ++i)
+      Record.push_back(VE.getAttributeGroupID(A.getSlotAttributes(i)));
 
-    Stream.EmitRecord(bitc::PARAMATTR_CODE_ENTRY_OLD, Record);
+    Stream.EmitRecord(bitc::PARAMATTR_CODE_ENTRY, Record);
     Record.clear();
   }