4 files changed, 184 insertions, 16 deletions
diff --git a/include/llvm/ADT/FoldingSet.h b/include/llvm/ADT/FoldingSet.h
index 52e0434..d2e0b8f 100644
--- a/include/llvm/ADT/FoldingSet.h
+++ b/include/llvm/ADT/FoldingSet.h
@@ -671,17 +671,10 @@ public:
 // Partial specializations of FoldingSetTrait.
 
 template<typename T> struct FoldingSetTrait<T*> {
-  static inline void Profile(const T *X, FoldingSetNodeID &ID) {
+  static inline void Profile(T *X, FoldingSetNodeID &ID) {
     ID.AddPointer(X);
   }
 };
-
-template<typename T> struct FoldingSetTrait<const T*> {
-  static inline void Profile(const T *X, FoldingSetNodeID &ID) {
-    ID.AddPointer(X);
-  }
-};
-
 } // End of namespace llvm.
 
 #endif
diff --git a/include/llvm/ADT/PackedVector.h b/include/llvm/ADT/PackedVector.h
new file mode 100644
index 0000000..272322a
--- /dev/null
+++ b/include/llvm/ADT/PackedVector.h
@@ -0,0 +1,158 @@
+//===- llvm/ADT/PackedVector.h - Packed values vector -----------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements the PackedVector class.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_ADT_PACKEDVECTOR_H
+#define LLVM_ADT_PACKEDVECTOR_H
+
+#include "llvm/ADT/BitVector.h"
+#include <limits>
+
+namespace llvm {
+
+template <typename T, unsigned BitNum, bool isSigned>
+class PackedVectorBase;
+
+// This won't be necessary if we can specialize members without specializing
+// the parent template.
+template <typename T, unsigned BitNum>
+class PackedVectorBase<T, BitNum, false> {
+protected:
+  static T getValue(const llvm::BitVector &Bits, unsigned Idx) {
+    T val = T();
+    for (unsigned i = 0; i != BitNum; ++i)
+      val = T(val | ((Bits[(Idx << (BitNum-1)) + i] ? 1UL : 0UL) << i));
+    return val;
+  }
+
+  static void setValue(llvm::BitVector &Bits, unsigned Idx, T val) {
+    assert((val >> BitNum) == 0 && "value is too big");
+    for (unsigned i = 0; i != BitNum; ++i)
+      Bits[(Idx << (BitNum-1)) + i] = val & (T(1) << i);
+  }
+};
+
+template <typename T, unsigned BitNum>
+class PackedVectorBase<T, BitNum, true> {
+protected:
+  static T getValue(const llvm::BitVector &Bits, unsigned Idx) {
+    T val = T();
+    for (unsigned i = 0; i != BitNum-1; ++i)
+      val = T(val | ((Bits[(Idx << (BitNum-1)) + i] ? 1UL : 0UL) << i));
+    if (Bits[(Idx << (BitNum-1)) + BitNum-1])
+      val = ~val;
+    return val;
+  }
+
+  static void setValue(llvm::BitVector &Bits, unsigned Idx, T val) {
+    if (val < 0) {
+      val = ~val;
+      Bits.set((Idx << (BitNum-1)) + BitNum-1);
+    }
+    assert((val >> (BitNum-1)) == 0 && "value is too big");
+    for (unsigned i = 0; i != BitNum-1; ++i)
+      Bits[(Idx << (BitNum-1)) + i] = val & (T(1) << i);
+  }
+};
+
+/// \brief Store a vector of values using a specific number of bits for each
+/// value. Both signed and unsigned types can be used, e.g
+/// @code
+///   PackedVector<signed, 2> vec;
+/// @endcode
+/// will create a vector accepting values -2, -1, 0, 1. Any other value will hit
+/// an assertion.
+template <typename T, unsigned BitNum>
+class PackedVector : public PackedVectorBase<T, BitNum,
+                                            std::numeric_limits<T>::is_signed> {
+  llvm::BitVector Bits;
+  typedef PackedVectorBase<T, BitNum, std::numeric_limits<T>::is_signed> base;
+
+public:
+  class reference {
+    PackedVector &Vec;
+    const unsigned Idx;
+
+    reference();  // Undefined    
+  public:
+    reference(PackedVector &vec, unsigned idx) : Vec(vec), Idx(idx) { }    
+
+    reference &operator=(T val) {
+      Vec.setValue(Vec.Bits, Idx, val);
+      return *this;
+    }
+    operator T() {
+      return Vec.getValue(Vec.Bits, Idx);
+    }
+  };
+
+  PackedVector() { }
+  explicit PackedVector(unsigned size) : Bits(size << (BitNum-1)) { }
+
+  bool empty() const { return Bits.empty(); }
+
+  unsigned size() const { return Bits.size() >> (BitNum-1); }
+  
+  void clear() { Bits.clear(); }
+  
+  void resize(unsigned N) { Bits.resize(N << (BitNum-1)); }
+
+  void reserve(unsigned N) { Bits.reserve(N << (BitNum-1)); }
+
+  PackedVector &reset() {
+    Bits.reset();
+    return *this;
+  }
+
+  void push_back(T val) {
+    resize(size()+1);
+    (*this)[size()-1] = val;
+  }
+
+  reference operator[](unsigned Idx) {
+    return reference(*this, Idx);
+  }
+
+  T operator[](unsigned Idx) const {
+    return base::getValue(Bits, Idx);
+  }
+
+  bool operator==(const PackedVector &RHS) const {
+    return Bits == RHS.Bits;
+  }
+
+  bool operator!=(const PackedVector &RHS) const {
+    return Bits != RHS.Bits;
+  }
+
+  const PackedVector &operator=(const PackedVector &RHS) {
+    Bits = RHS.Bits;
+    return *this;
+  }
+
+  PackedVector &operator|=(const PackedVector &RHS) {
+    Bits |= RHS.Bits;
+    return *this;
+  }
+
+  void swap(PackedVector &RHS) {
+    Bits.swap(RHS.Bits);
+  }
+};
+
+// Leave BitNum=0 undefined. 
+template <typename T>
+class PackedVector<T, 0>;
+
+} // end llvm namespace
+
+#endif
diff --git a/include/llvm/ADT/StringRef.h b/include/llvm/ADT/StringRef.h
index 1766d2b..8396921 100644
--- a/include/llvm/ADT/StringRef.h
+++ b/include/llvm/ADT/StringRef.h
@@ -46,7 +46,14 @@ namespace llvm {
     // integer works around this bug.
     static size_t min(size_t a, size_t b) { return a < b ? a : b; }
     static size_t max(size_t a, size_t b) { return a > b ? a : b; }
-
+    
+    // Workaround memcmp issue with null pointers (undefined behavior)
+    // by providing a specialized version
+    static int compareMemory(const char *Lhs, const char *Rhs, size_t Length) {
+      if (Length == 0) { return 0; }
+      return ::memcmp(Lhs,Rhs,Length);
+    }
+    
   public:
     /// @name Constructors
     /// @{
@@ -56,11 +63,17 @@ namespace llvm {
 
     /// Construct a string ref from a cstring.
     /*implicit*/ StringRef(const char *Str)
-      : Data(Str), Length(::strlen(Str)) {}
+      : Data(Str) {
+        assert(Str && "StringRef cannot be built from a NULL argument");
+        Length = ::strlen(Str); // invoking strlen(NULL) is undefined behavior
+      }
 
     /// Construct a string ref from a pointer and length.
     /*implicit*/ StringRef(const char *data, size_t length)
-      : Data(data), Length(length) {}
+      : Data(data), Length(length) {
+        assert((data || length == 0) &&
+        "StringRef cannot be built from a NULL argument with non-null length");
+      }
 
     /// Construct a string ref from an std::string.
     /*implicit*/ StringRef(const std::string &Str)
@@ -104,7 +117,7 @@ namespace llvm {
     /// compare() when the relative ordering of inequal strings isn't needed.
     bool equals(StringRef RHS) const {
       return (Length == RHS.Length &&
-              memcmp(Data, RHS.Data, RHS.Length) == 0);
+              compareMemory(Data, RHS.Data, RHS.Length) == 0);
     }
 
     /// equals_lower - Check for string equality, ignoring case.
@@ -116,7 +129,7 @@ namespace llvm {
     /// is lexicographically less than, equal to, or greater than the \arg RHS.
     int compare(StringRef RHS) const {
       // Check the prefix for a mismatch.
-      if (int Res = memcmp(Data, RHS.Data, min(Length, RHS.Length)))
+      if (int Res = compareMemory(Data, RHS.Data, min(Length, RHS.Length)))
         return Res < 0 ? -1 : 1;
 
       // Otherwise the prefixes match, so we only need to check the lengths.
@@ -183,13 +196,13 @@ namespace llvm {
     /// startswith - Check if this string starts with the given \arg Prefix.
     bool startswith(StringRef Prefix) const {
       return Length >= Prefix.Length &&
-             memcmp(Data, Prefix.Data, Prefix.Length) == 0;
+             compareMemory(Data, Prefix.Data, Prefix.Length) == 0;
     }
 
     /// endswith - Check if this string ends with the given \arg Suffix.
     bool endswith(StringRef Suffix) const {
       return Length >= Suffix.Length &&
-             memcmp(end() - Suffix.Length, Suffix.Data, Suffix.Length) == 0;
+        compareMemory(end() - Suffix.Length, Suffix.Data, Suffix.Length) == 0;
     }
 
     /// @}
@@ -447,6 +460,10 @@ namespace llvm {
     return LHS.compare(RHS) != -1;
   }
 
+  inline std::string &operator+=(std::string &buffer, llvm::StringRef string) {
+    return buffer.append(string.data(), string.size());
+  }
+
   /// @}
 
   // StringRefs can be treated like a POD type.
diff --git a/include/llvm/ADT/Triple.h b/include/llvm/ADT/Triple.h
index 2659bce..078033d 100644
--- a/include/llvm/ADT/Triple.h
+++ b/include/llvm/ADT/Triple.h
@@ -225,7 +225,7 @@ public:
   /// if the environment component is present).
   StringRef getOSAndEnvironmentName() const;
 
-  /// getOSNumber - Parse the version number from the OS name component of the
+  /// getOSVersion - Parse the version number from the OS name component of the
   /// triple, if present.
   ///
   /// For example, "fooos1.2.3" would return (1, 2, 3).