5 files changed, 448 insertions, 89 deletions

diff --git a/include/llvm/ADT/BitVector.h b/include/llvm/ADT/BitVector.h
index 9c046efaaddd..45108c8cc519 100644
--- a/include/llvm/ADT/BitVector.h
+++ b/include/llvm/ADT/BitVector.h
@@ -95,6 +95,9 @@ public:
     delete[] Bits;
   }
 
+  /// empty - Tests whether there are no bits in this bitvector.
+  bool empty() const { return Size == 0; }
+
   /// size - Returns the number of bits in this bitvector.
   unsigned size() const { return Size; }
 
@@ -341,6 +344,12 @@ public:
     return *this;
   }
 
+  void swap(BitVector &RHS) {
+    std::swap(Bits, RHS.Bits);
+    std::swap(Size, RHS.Size);
+    std::swap(Capacity, RHS.Capacity);
+  }
+
 private:
   unsigned NumBitWords(unsigned S) const {
     return (S + BITWORD_SIZE-1) / BITWORD_SIZE;
@@ -406,4 +415,13 @@ inline BitVector operator^(const BitVector &LHS, const BitVector &RHS) {
 }
 
 } // End llvm namespace
+
+namespace std {
+  /// Implement std::swap in terms of BitVector swap.
+  inline void
+  swap(llvm::BitVector &LHS, llvm::BitVector &RHS) {
+    LHS.swap(RHS);
+  }
+}
+
 #endif
diff --git a/include/llvm/ADT/SmallBitVector.h b/include/llvm/ADT/SmallBitVector.h
new file mode 100644
index 000000000000..346fb1ca43dc
--- /dev/null
+++ b/include/llvm/ADT/SmallBitVector.h
@@ -0,0 +1,373 @@
+//===- llvm/ADT/SmallBitVector.h - 'Normally small' bit vectors -*- 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 SmallBitVector class.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_ADT_SMALLBITVECTOR_H
+#define LLVM_ADT_SMALLBITVECTOR_H
+
+#include "llvm/ADT/BitVector.h"
+#include "llvm/ADT/PointerIntPair.h"
+#include "llvm/Support/MathExtras.h"
+#include <cassert>
+
+namespace llvm {
+
+/// SmallBitVector - This is a 'bitvector' (really, a variable-sized bit array),
+/// optimized for the case when the array is small.  It contains one
+/// pointer-sized field, which is directly used as a plain collection of bits
+/// when possible, or as a pointer to a larger heap-allocated array when
+/// necessary.  This allows normal "small" cases to be fast without losing
+/// generality for large inputs.
+///
+class SmallBitVector {
+  // TODO: In "large" mode, a pointer to a BitVector is used, leading to an
+  // unnecessary level of indirection. It would be more efficient to use a
+  // pointer to memory containing size, allocation size, and the array of bits.
+  PointerIntPair<BitVector *, 1, uintptr_t> X;
+
+  // The number of bits in this class.
+  static const size_t NumBaseBits = sizeof(uintptr_t) * CHAR_BIT;
+
+  // One bit is used to discriminate between small and large mode. The
+  // remaining bits are used for the small-mode representation.
+  static const size_t SmallNumRawBits = NumBaseBits - 1;
+
+  // A few more bits are used to store the size of the bit set in small mode.
+  // Theoretically this is a ceil-log2. These bits are encoded in the most
+  // significant bits of the raw bits.
+  static const size_t SmallNumSizeBits = (NumBaseBits == 32 ? 5 :
+                                          NumBaseBits == 64 ? 6 :
+                                          SmallNumRawBits);
+
+  // The remaining bits are used to store the actual set in small mode.
+  static const size_t SmallNumDataBits = SmallNumRawBits - SmallNumSizeBits;
+
+  bool isSmall() const {
+    return X.getInt();
+  }
+
+  void switchToSmall(uintptr_t NewSmallBits, size_t NewSize) {
+    X.setInt(true);
+    setSmallSize(NewSize);
+    setSmallBits(NewSmallBits);
+  }
+
+  void switchToLarge(BitVector *BV) {
+    X.setInt(false);
+    X.setPointer(BV);
+  }
+
+  // Return all the bits used for the "small" representation; this includes
+  // bits for the size as well as the element bits.
+  uintptr_t getSmallRawBits() const {
+    return reinterpret_cast<uintptr_t>(X.getPointer()) >> 1;
+  }
+
+  void setSmallRawBits(uintptr_t NewRawBits) {
+    return X.setPointer(reinterpret_cast<BitVector *>(NewRawBits << 1));
+  }
+
+  // Return the size.
+  size_t getSmallSize() const {
+    return getSmallRawBits() >> SmallNumDataBits;
+  }
+
+  void setSmallSize(size_t Size) {
+    setSmallRawBits(getSmallBits() | (Size << SmallNumDataBits));
+  }
+
+  // Return the element bits.
+  uintptr_t getSmallBits() const {
+    return getSmallRawBits() & ~(~uintptr_t(0) << SmallNumDataBits);
+  }
+
+  void setSmallBits(uintptr_t NewBits) {
+    setSmallRawBits((getSmallRawBits() & (~uintptr_t(0) << SmallNumDataBits)) |
+                    (NewBits & ~(~uintptr_t(0) << getSmallSize())));
+  }
+
+public:
+  /// SmallBitVector default ctor - Creates an empty bitvector.
+  SmallBitVector() : X(0, 1) {}
+
+  /// SmallBitVector ctor - Creates a bitvector of specified number of bits. All
+  /// bits are initialized to the specified value.
+  explicit SmallBitVector(unsigned s, bool t = false) : X(0, 1) {
+    if (s <= SmallNumRawBits)
+      switchToSmall(t ? ~uintptr_t(0) : 0, s);
+    else
+      switchToLarge(new BitVector(s, t));
+  }
+
+  /// SmallBitVector copy ctor.
+  SmallBitVector(const SmallBitVector &RHS) {
+    if (RHS.isSmall())
+      X = RHS.X;
+    else
+      switchToLarge(new BitVector(*RHS.X.getPointer()));
+  }
+
+  ~SmallBitVector() {
+    if (!isSmall())
+      delete X.getPointer();
+  }
+
+  /// empty - Tests whether there are no bits in this bitvector.
+  bool empty() const {
+    return isSmall() ? getSmallSize() == 0 : X.getPointer()->empty();
+  }
+
+  /// size - Returns the number of bits in this bitvector.
+  size_t size() const {
+    return isSmall() ? getSmallSize() : X.getPointer()->size();
+  }
+
+  /// count - Returns the number of bits which are set.
+  unsigned count() const {
+    if (isSmall()) {
+      uintptr_t Bits = getSmallBits();
+      if (sizeof(uintptr_t) * CHAR_BIT == 32)
+        return CountPopulation_32(Bits);
+      if (sizeof(uintptr_t) * CHAR_BIT == 64)
+        return CountPopulation_64(Bits);
+      assert(0 && "Unsupported!");
+    }
+    return X.getPointer()->count();
+  }
+
+  /// any - Returns true if any bit is set.
+  bool any() const {
+    if (isSmall())
+      return getSmallBits() != 0;
+    return X.getPointer()->any();
+  }
+
+  /// none - Returns true if none of the bits are set.
+  bool none() const {
+    if (isSmall())
+      return getSmallBits() == 0;
+    return X.getPointer()->none();
+  }
+
+  /// find_first - Returns the index of the first set bit, -1 if none
+  /// of the bits are set.
+  int find_first() const {
+    if (isSmall()) {
+      uintptr_t Bits = getSmallBits();
+      if (sizeof(uintptr_t) * CHAR_BIT == 32)
+        return CountTrailingZeros_32(Bits);
+      if (sizeof(uintptr_t) * CHAR_BIT == 64)
+        return CountTrailingZeros_64(Bits);
+      assert(0 && "Unsupported!");
+    }
+    return X.getPointer()->find_first();
+  }
+
+  /// find_next - Returns the index of the next set bit following the
+  /// "Prev" bit. Returns -1 if the next set bit is not found.
+  int find_next(unsigned Prev) const {
+    if (isSmall()) {
+      uintptr_t Bits = getSmallBits();
+      // Mask off previous bits.
+      Bits &= ~uintptr_t(0) << Prev;
+      if (sizeof(uintptr_t) * CHAR_BIT == 32)
+        return CountTrailingZeros_32(Bits);
+      if (sizeof(uintptr_t) * CHAR_BIT == 64)
+        return CountTrailingZeros_64(Bits);
+      assert(0 && "Unsupported!");
+    }
+    return X.getPointer()->find_next(Prev);
+  }
+
+  /// clear - Clear all bits.
+  void clear() {
+    if (!isSmall())
+      delete X.getPointer();
+    switchToSmall(0, 0);
+  }
+
+  /// resize - Grow or shrink the bitvector.
+  void resize(unsigned N, bool t = false) {
+    if (!isSmall()) {
+      X.getPointer()->resize(N, t);
+    } else if (getSmallSize() >= N) {
+      setSmallSize(N);
+      setSmallBits(getSmallBits());
+    } else {
+      BitVector *BV = new BitVector(N, t);
+      uintptr_t OldBits = getSmallBits();
+      for (size_t i = 0, e = getSmallSize(); i != e; ++i)
+        (*BV)[i] = (OldBits >> i) & 1;
+      switchToLarge(BV);
+    }
+  }
+
+  void reserve(unsigned N) {
+    if (isSmall()) {
+      if (N > SmallNumDataBits) {
+        uintptr_t OldBits = getSmallRawBits();
+        size_t SmallSize = getSmallSize();
+        BitVector *BV = new BitVector(SmallSize);
+        for (size_t i = 0; i < SmallSize; ++i)
+          if ((OldBits >> i) & 1)
+            BV->set(i);
+        BV->reserve(N);
+        switchToLarge(BV);
+      }
+    } else {
+      X.getPointer()->reserve(N);
+    }
+  }
+
+  // Set, reset, flip
+  SmallBitVector &set() {
+    if (isSmall())
+      setSmallBits(~uintptr_t(0));
+    else
+      X.getPointer()->set();
+    return *this;
+  }
+
+  SmallBitVector &set(unsigned Idx) {
+    if (isSmall())
+      setSmallBits(getSmallBits() | (uintptr_t(1) << Idx));
+    else
+      X.getPointer()->set(Idx);
+    return *this;
+  }
+
+  SmallBitVector &reset() {
+    if (isSmall())
+      setSmallBits(0);
+    else
+      X.getPointer()->reset();
+    return *this;
+  }
+
+  SmallBitVector &reset(unsigned Idx) {
+    if (isSmall())
+      setSmallBits(getSmallBits() & ~(uintptr_t(1) << Idx));
+    else
+      X.getPointer()->reset(Idx);
+    return *this;
+  }
+
+  SmallBitVector &flip() {
+    if (isSmall())
+      setSmallBits(~getSmallBits());
+    else
+      X.getPointer()->flip();
+    return *this;
+  }
+
+  SmallBitVector &flip(unsigned Idx) {
+    if (isSmall())
+      setSmallBits(getSmallBits() ^ (uintptr_t(1) << Idx));
+    else
+      X.getPointer()->flip(Idx);
+    return *this;
+  }
+
+  // No argument flip.
+  SmallBitVector operator~() const {
+    return SmallBitVector(*this).flip();
+  }
+
+  // Indexing.
+  // TODO: Add an index operator which returns a "reference" (proxy class).
+  bool operator[](unsigned Idx) const {
+    assert(Idx < size() && "Out-of-bounds Bit access.");
+    if (isSmall())
+      return ((getSmallBits() >> Idx) & 1) != 0;
+    return X.getPointer()->operator[](Idx);
+  }
+
+  bool test(unsigned Idx) const {
+    return (*this)[Idx];
+  }
+
+  // Comparison operators.
+  bool operator==(const SmallBitVector &RHS) const {
+    if (size() != RHS.size())
+      return false;
+    if (isSmall())
+      return getSmallBits() == RHS.getSmallBits();
+    else
+      return *X.getPointer() == *RHS.X.getPointer();
+  }
+
+  bool operator!=(const SmallBitVector &RHS) const {
+    return !(*this == RHS);
+  }
+
+  // Intersection, union, disjoint union.
+  BitVector &operator&=(const SmallBitVector &RHS); // TODO: implement
+
+  BitVector &operator|=(const SmallBitVector &RHS); // TODO: implement
+
+  BitVector &operator^=(const SmallBitVector &RHS); // TODO: implement
+
+  // Assignment operator.
+  const SmallBitVector &operator=(const SmallBitVector &RHS) {
+    if (isSmall()) {
+      if (RHS.isSmall())
+        X = RHS.X;
+      else
+        switchToLarge(new BitVector(*RHS.X.getPointer()));
+    } else {
+      if (!RHS.isSmall())
+        *X.getPointer() = *RHS.X.getPointer();
+      else {
+        delete X.getPointer();
+        X = RHS.X;
+      }
+    }
+    return *this;
+  }
+
+  void swap(SmallBitVector &RHS) {
+    std::swap(X, RHS.X);
+  }
+};
+
+inline SmallBitVector
+operator&(const SmallBitVector &LHS, const SmallBitVector &RHS) {
+  SmallBitVector Result(LHS);
+  Result &= RHS;
+  return Result;
+}
+
+inline SmallBitVector
+operator|(const SmallBitVector &LHS, const SmallBitVector &RHS) {
+  SmallBitVector Result(LHS);
+  Result |= RHS;
+  return Result;
+}
+
+inline SmallBitVector
+operator^(const SmallBitVector &LHS, const SmallBitVector &RHS) {
+  SmallBitVector Result(LHS);
+  Result ^= RHS;
+  return Result;
+}
+
+} // End llvm namespace
+
+namespace std {
+  /// Implement std::swap in terms of BitVector swap.
+  inline void
+  swap(llvm::SmallBitVector &LHS, llvm::SmallBitVector &RHS) {
+    LHS.swap(RHS);
+  }
+}
+
+#endif
diff --git a/include/llvm/ADT/StringExtras.h b/include/llvm/ADT/StringExtras.h
index 85936c019d3b..1ea546f46f29 100644
--- a/include/llvm/ADT/StringExtras.h
+++ b/include/llvm/ADT/StringExtras.h
@@ -23,6 +23,7 @@
 #include <vector>
 
 namespace llvm {
+template<typename T> class SmallVectorImpl;
 
 /// hexdigit - Return the (uppercase) hexadecimal character for the
 /// given number \arg X (which should be less than 16).
@@ -136,86 +137,25 @@ static inline std::string UppercaseString(const std::string &S) {
   return result;
 }
 
-/// StringsEqualNoCase - Return true if the two strings are equal, ignoring
-/// case.
-static inline bool StringsEqualNoCase(const std::string &LHS,
-                                      const std::string &RHS) {
-  if (LHS.size() != RHS.size()) return false;
-  for (unsigned i = 0, e = static_cast<unsigned>(LHS.size()); i != e; ++i)
-    if (tolower(LHS[i]) != tolower(RHS[i])) return false;
-  return true;
-}
-
-/// StringsEqualNoCase - Return true if the two strings are equal, ignoring
-/// case.
-static inline bool StringsEqualNoCase(const std::string &LHS,
-                                      const char *RHS) {
-  for (unsigned i = 0, e = static_cast<unsigned>(LHS.size()); i != e; ++i) {
-    if (RHS[i] == 0) return false;  // RHS too short.
-    if (tolower(LHS[i]) != tolower(RHS[i])) return false;
-  }
-  return RHS[LHS.size()] == 0;  // Not too long?
-}
-  
-/// StringsEqualNoCase - Return true if the two null-terminated C strings are
-///  equal, ignoring
-
-static inline bool StringsEqualNoCase(const char *LHS, const char *RHS,
-                                      unsigned len) {
-
-  for (unsigned i = 0; i < len; ++i) {
-    if (tolower(LHS[i]) != tolower(RHS[i]))
-      return false;
-    
-    // If RHS[i] == 0 then LHS[i] == 0 or otherwise we would have returned
-    // at the previous branch as tolower('\0') == '\0'.
-    if (RHS[i] == 0)
-      return true;
-  }
-  
-  return true;
-}
-
-/// CStrInCStrNoCase - Portable version of strcasestr.  Locates the first
-///  occurance of c-string 's2' in string 's1', ignoring case.  Returns
-///  NULL if 's2' cannot be found.
-static inline const char* CStrInCStrNoCase(const char *s1, const char *s2) {
-
-  // Are either strings NULL or empty?
-  if (!s1 || !s2 || s1[0] == '\0' || s2[0] == '\0')
-    return 0;
-
-  if (s1 == s2)
-    return s1;
-
-  const char *I1=s1, *I2=s2;
-
-  while (*I1 != '\0' && *I2 != '\0' )
-    if (tolower(*I1) != tolower(*I2)) { // No match.  Start over.
-      ++s1; I1 = s1; I2 = s2;
-    }
-    else { // Character match.  Advance to the next character.
-      ++I1; ++I2;
-    }
-
-  // If we exhausted all of the characters in 's2', then 's2' appears in 's1'.
-  return *I2 == '\0' ? s1 : 0;
-}
+/// StrInStrNoCase - Portable version of strcasestr.  Locates the first
+/// occurrence of string 's1' in string 's2', ignoring case.  Returns
+/// the offset of s2 in s1 or npos if s2 cannot be found.
+StringRef::size_type StrInStrNoCase(StringRef s1, StringRef s2);
 
 /// getToken - This function extracts one token from source, ignoring any
 /// leading characters that appear in the Delimiters string, and ending the
 /// token at any of the characters that appear in the Delimiters string.  If
 /// there are no tokens in the source string, an empty string is returned.
-/// The Source source string is updated in place to remove the returned string
-/// and any delimiter prefix from it.
-std::string getToken(std::string &Source,
-                     const char *Delimiters = " \t\n\v\f\r");
+/// The function returns a pair containing the extracted token and the
+/// remaining tail string.
+std::pair<StringRef, StringRef> getToken(StringRef Source,
+                                         StringRef Delimiters = " \t\n\v\f\r");
 
 /// SplitString - Split up the specified string according to the specified
 /// delimiters, appending the result fragments to the output list.
-void SplitString(const std::string &Source,
-                 std::vector<std::string> &OutFragments,
-                 const char *Delimiters = " \t\n\v\f\r");
+void SplitString(StringRef Source,
+                 SmallVectorImpl<StringRef> &OutFragments,
+                 StringRef Delimiters = " \t\n\v\f\r");
 
 /// HashString - Hash funtion for strings.
 ///
diff --git a/include/llvm/ADT/StringRef.h b/include/llvm/ADT/StringRef.h
index 1c738369d75e..3064af3abbca 100644
--- a/include/llvm/ADT/StringRef.h
+++ b/include/llvm/ADT/StringRef.h
@@ -29,6 +29,7 @@ namespace llvm {
   class StringRef {
   public:
     typedef const char *iterator;
+    typedef const char *const_iterator;
     static const size_t npos = ~size_t(0);
     typedef size_t size_type;
 
@@ -42,15 +43,8 @@ namespace llvm {
     // Workaround PR5482: nearly all gcc 4.x miscompile StringRef and std::min()
     // Changing the arg of min to be an integer, instead of a reference to an
     // integer works around this bug.
-    size_t min(size_t a, size_t b) const
-    {
-      return a < b ? a : b;
-    }
-
-    size_t max(size_t a, size_t b) const
-    {
-      return a > b ? a : b;
-    }
+    size_t min(size_t a, size_t b) const { return a < b ? a : b; }
+    size_t max(size_t a, size_t b) const { return a > b ? a : b; }
 
   public:
     /// @name Constructors
@@ -191,7 +185,7 @@ namespace llvm {
 
     /// find - Search for the first character \arg C in the string.
     ///
-    /// \return - The index of the first occurence of \arg C, or npos if not
+    /// \return - The index of the first occurrence of \arg C, or npos if not
     /// found.
     size_t find(char C, size_t From = 0) const {
       for (size_t i = min(From, Length), e = Length; i != e; ++i)
@@ -202,13 +196,13 @@ namespace llvm {
 
     /// find - Search for the first string \arg Str in the string.
     ///
-    /// \return - The index of the first occurence of \arg Str, or npos if not
+    /// \return - The index of the first occurrence of \arg Str, or npos if not
     /// found.
     size_t find(StringRef Str, size_t From = 0) const;
 
     /// rfind - Search for the last character \arg C in the string.
     ///
-    /// \return - The index of the last occurence of \arg C, or npos if not
+    /// \return - The index of the last occurrence of \arg C, or npos if not
     /// found.
     size_t rfind(char C, size_t From = npos) const {
       From = min(From, Length);
@@ -223,7 +217,7 @@ namespace llvm {
 
     /// rfind - Search for the last string \arg Str in the string.
     ///
-    /// \return - The index of the last occurence of \arg Str, or npos if not
+    /// \return - The index of the last occurrence of \arg Str, or npos if not
     /// found.
     size_t rfind(StringRef Str) const;
 
@@ -313,7 +307,7 @@ namespace llvm {
       return StringRef(Data + Start, End - Start);
     }
 
-    /// split - Split into two substrings around the first occurence of a
+    /// split - Split into two substrings around the first occurrence of a
     /// separator character.
     ///
     /// If \arg Separator is in the string, then the result is a pair (LHS, RHS)
@@ -330,7 +324,7 @@ namespace llvm {
       return std::make_pair(slice(0, Idx), slice(Idx+1, npos));
     }
 
-    /// split - Split into two substrings around the first occurence of a
+    /// split - Split into two substrings around the first occurrence of a
     /// separator string.
     ///
     /// If \arg Separator is in the string, then the result is a pair (LHS, RHS)
@@ -347,7 +341,7 @@ namespace llvm {
       return std::make_pair(slice(0, Idx), slice(Idx + Separator.size(), npos));
     }
 
-    /// split - Split into substrings around the occurences of a separator
+    /// split - Split into substrings around the occurrences of a separator
     /// string.
     ///
     /// Each substring is stored in \arg A. If \arg MaxSplit is >= 0, at most
@@ -366,7 +360,7 @@ namespace llvm {
                StringRef Separator, int MaxSplit = -1,
                bool KeepEmpty = true) const;
 
-    /// rsplit - Split into two substrings around the last occurence of a
+    /// rsplit - Split into two substrings around the last occurrence of a
     /// separator character.
     ///
     /// If \arg Separator is in the string, then the result is a pair (LHS, RHS)
diff --git a/include/llvm/ADT/Twine.h b/include/llvm/ADT/Twine.h
index ca0be53d481d..97e9df445817 100644
--- a/include/llvm/ADT/Twine.h
+++ b/include/llvm/ADT/Twine.h
@@ -329,6 +329,22 @@ namespace llvm {
     bool isTriviallyEmpty() const {
       return isNullary();
     }
+    
+    /// isSingleStringRef - Return true if this twine can be dynamically
+    /// accessed as a single StringRef value with getSingleStringRef().
+    bool isSingleStringRef() const {
+      if (getRHSKind() != EmptyKind) return false;
+      
+      switch (getLHSKind()) {
+      case EmptyKind:
+      case CStringKind:
+      case StdStringKind:
+      case StringRefKind:
+        return true;
+      default:
+        return false;
+      }
+    }
 
     /// @}
     /// @name String Operations
@@ -347,6 +363,24 @@ namespace llvm {
     /// SmallVector.
     void toVector(SmallVectorImpl<char> &Out) const;
 
+    /// getSingleStringRef - This returns the twine as a single StringRef.  This
+    /// method is only valid if isSingleStringRef() is true.
+    StringRef getSingleStringRef() const {
+      assert(isSingleStringRef() &&"This cannot be had as a single stringref!");
+      switch (getLHSKind()) {
+      default: assert(0 && "Out of sync with isSingleStringRef");
+      case EmptyKind:      return StringRef();
+      case CStringKind:    return StringRef((const char*)LHS);
+      case StdStringKind:  return StringRef(*(const std::string*)LHS);
+      case StringRefKind:  return *(const StringRef*)LHS;
+      }
+    }
+
+    /// toStringRef - This returns the twine as a single StringRef if it can be
+    /// represented as such. Otherwise the twine is written into the given
+    /// SmallVector and a StringRef to the SmallVector's data is returned.
+    StringRef toStringRef(SmallVectorImpl<char> &Out) const;
+
     /// print - Write the concatenated string represented by this twine to the
     /// stream \arg OS.
     void print(raw_ostream &OS) const;