From c835b8c30127d15599de2d614434d39a6cc3ae17 Mon Sep 17 00:00:00 2001
From: Benjamin Kramer <benny.kra@googlemail.com>
Date: Sat, 16 Feb 2013 19:13:18 +0000
Subject: Turn the enum attributes DenseSet in AttrBuilder into a set of bits.

Avoids malloc and is a lot denser. We lose iteration over target independent
attributes, but that's a strange interface anyways and didn't have any users
outside of AttrBuilder.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@175370 91177308-0d34-0410-b5e6-96231b3b80d8
---
 include/llvm/IR/Attributes.h | 55 ++++++++++++--------------------------------
 1 file changed, 15 insertions(+), 40 deletions(-)

(limited to 'include/llvm/IR/Attributes.h')

diff --git a/include/llvm/IR/Attributes.h b/include/llvm/IR/Attributes.h
index b6ca1ad9f9..d3190ffae4 100644
--- a/include/llvm/IR/Attributes.h
+++ b/include/llvm/IR/Attributes.h
@@ -17,8 +17,8 @@
 #define LLVM_IR_ATTRIBUTES_H
 
 #include "llvm/ADT/ArrayRef.h"
-#include "llvm/ADT/DenseSet.h"
 #include "llvm/ADT/FoldingSet.h"
+#include "llvm/Support/PointerLikeTypeTraits.h"
 #include <cassert>
 #include <map>
 #include <string>
@@ -30,6 +30,7 @@ class AttributeImpl;
 class AttributeSetImpl;
 class AttributeSetNode;
 class Constant;
+template<typename T> struct DenseMapInfo;
 class LLVMContext;
 class Type;
 
@@ -101,9 +102,6 @@ public:
     ZExt,                  ///< Zero extended before/after call
 
     EndAttrKinds,          ///< Sentinal value useful for loops
-
-    AttrKindEmptyKey,      ///< Empty key value for DenseMapInfo
-    AttrKindTombstoneKey   ///< Tombstone key value for DenseMapInfo
   };
 private:
   AttributeImpl *pImpl;
@@ -185,26 +183,6 @@ public:
   }
 };
 
-//===----------------------------------------------------------------------===//
-/// \class
-/// \brief Provide DenseMapInfo for Attribute::AttrKinds. This is used by
-/// AttrBuilder.
-template<> struct DenseMapInfo<Attribute::AttrKind> {
-  static inline Attribute::AttrKind getEmptyKey() {
-    return Attribute::AttrKindEmptyKey;
-  }
-  static inline Attribute::AttrKind getTombstoneKey() {
-    return Attribute::AttrKindTombstoneKey;
-  }
-  static unsigned getHashValue(const Attribute::AttrKind &Val) {
-    return Val * 37U;
-  }
-  static bool isEqual(const Attribute::AttrKind &LHS,
-                      const Attribute::AttrKind &RHS) {
-    return LHS == RHS;
-  }
-};
-
 //===----------------------------------------------------------------------===//
 /// \class
 /// \brief This class holds the attributes for a function, its return value, and
@@ -400,16 +378,17 @@ template<> struct DenseMapInfo<AttributeSet> {
 /// value, however, is not. So this can be used as a quick way to test for
 /// equality, presence of attributes, etc.
 class AttrBuilder {
-  DenseSet<Attribute::AttrKind> Attrs;
+  uint64_t Attrs;
   std::map<std::string, std::string> TargetDepAttrs;
   uint64_t Alignment;
   uint64_t StackAlignment;
 public:
-  AttrBuilder() : Alignment(0), StackAlignment(0) {}
-  explicit AttrBuilder(uint64_t Val) : Alignment(0), StackAlignment(0) {
+  AttrBuilder() : Attrs(0), Alignment(0), StackAlignment(0) {}
+  explicit AttrBuilder(uint64_t Val)
+    : Attrs(0), Alignment(0), StackAlignment(0) {
     addRawValue(Val);
   }
-  AttrBuilder(const Attribute &A) : Alignment(0), StackAlignment(0) {
+  AttrBuilder(const Attribute &A) : Attrs(0), Alignment(0), StackAlignment(0) {
     addAttribute(A);
   }
   AttrBuilder(AttributeSet AS, unsigned Idx);
@@ -442,7 +421,11 @@ public:
   AttrBuilder &merge(const AttrBuilder &B);
 
   /// \brief Return true if the builder has the specified attribute.
-  bool contains(Attribute::AttrKind A) const;
+  bool contains(Attribute::AttrKind A) const {
+    assert((unsigned)A < 64 && A < Attribute::EndAttrKinds &&
+           "Attribute out of range!");
+    return Attrs & (1ULL << A);
+  }
 
   /// \brief Return true if the builder has the specified target-dependent
   /// attribute.
@@ -472,17 +455,9 @@ public:
   /// the form used internally in Attribute.
   AttrBuilder &addStackAlignmentAttr(unsigned Align);
 
-  // Iterators for target-independent attributes.
-  typedef DenseSet<Attribute::AttrKind>::iterator       iterator;
-  typedef DenseSet<Attribute::AttrKind>::const_iterator const_iterator;
-
-  iterator begin()             { return Attrs.begin(); }
-  iterator end()               { return Attrs.end(); }
-
-  const_iterator begin() const { return Attrs.begin(); }
-  const_iterator end() const   { return Attrs.end(); }
-
-  bool empty() const           { return Attrs.empty(); }
+  /// \brief Return true if the builder contains no target-independent
+  /// attributes.
+  bool empty() const { return Attrs == 0; }
 
   // Iterators for target-dependent attributes.
   typedef std::pair<std::string, std::string>                td_type;
-- 
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