lib/llvm/Support/StringRef.cpp - third_party/swift-llbuild - Git at Google

 //===-- StringRef.cpp - Lightweight String References ---------------------===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//

 #include "llvm/ADT/StringRef.h"
 #include "llvm/ADT/Hashing.h"
 #include "llvm/ADT/edit_distance.h"
 #include <bitset>
 #include <climits>

 using namespace llvm;

 // MSVC emits references to this into the translation units which reference it.
 #ifndef _MSC_VER
 const size_t StringRef::npos;
 #endif

 static char ascii_tolower(char x) {
   if (x >= 'A' && x <= 'Z')
     return x - 'A' + 'a';
   return x;
 }

 static char ascii_toupper(char x) {
   if (x >= 'a' && x <= 'z')
     return x - 'a' + 'A';
   return x;
 }

 static bool ascii_isdigit(char x) {
   return x >= '0' && x <= '9';
 }

 // strncasecmp() is not available on non-POSIX systems, so define an
 // alternative function here.
 static int ascii_strncasecmp(const char *LHS, const char *RHS, size_t Length) {
   for (size_t I = 0; I < Length; ++I) {
     unsigned char LHC = ascii_tolower(LHS[I]);
     unsigned char RHC = ascii_tolower(RHS[I]);
     if (LHC != RHC)
       return LHC < RHC ? -1 : 1;
   }
   return 0;
 }

 /// compare_lower - Compare strings, ignoring case.
 int StringRef::compare_lower(StringRef RHS) const {
   if (int Res = ascii_strncasecmp(Data, RHS.Data, std::min(Length, RHS.Length)))
     return Res;
   if (Length == RHS.Length)
     return 0;
   return Length < RHS.Length ? -1 : 1;
 }

 /// Check if this string starts with the given \p Prefix, ignoring case.
 bool StringRef::startswith_lower(StringRef Prefix) const {
   return Length >= Prefix.Length &&
       ascii_strncasecmp(Data, Prefix.Data, Prefix.Length) == 0;
 }

 /// Check if this string ends with the given \p Suffix, ignoring case.
 bool StringRef::endswith_lower(StringRef Suffix) const {
   return Length >= Suffix.Length &&
       ascii_strncasecmp(end() - Suffix.Length, Suffix.Data, Suffix.Length) == 0;
 }

 /// compare_numeric - Compare strings, handle embedded numbers.
 int StringRef::compare_numeric(StringRef RHS) const {
   for (size_t I = 0, E = std::min(Length, RHS.Length); I != E; ++I) {
     // Check for sequences of digits.
     if (ascii_isdigit(Data[I]) && ascii_isdigit(RHS.Data[I])) {
       // The longer sequence of numbers is considered larger.
       // This doesn't really handle prefixed zeros well.
       size_t J;
       for (J = I + 1; J != E + 1; ++J) {
         bool ld = J < Length && ascii_isdigit(Data[J]);
         bool rd = J < RHS.Length && ascii_isdigit(RHS.Data[J]);
         if (ld != rd)
           return rd ? -1 : 1;
         if (!rd)
           break;
       }
       // The two number sequences have the same length (J-I), just memcmp them.
       if (int Res = compareMemory(Data + I, RHS.Data + I, J - I))
         return Res < 0 ? -1 : 1;
       // Identical number sequences, continue search after the numbers.
       I = J - 1;
       continue;
     }
     if (Data[I] != RHS.Data[I])
       return (unsigned char)Data[I] < (unsigned char)RHS.Data[I] ? -1 : 1;
   }
   if (Length == RHS.Length)
     return 0;
   return Length < RHS.Length ? -1 : 1;
 }

 // Compute the edit distance between the two given strings.
 unsigned StringRef::edit_distance(llvm::StringRef Other,
                                   bool AllowReplacements,
                                   unsigned MaxEditDistance) const {
   return llvm::ComputeEditDistance(
       makeArrayRef(data(), size()),
       makeArrayRef(Other.data(), Other.size()),
       AllowReplacements, MaxEditDistance);
 }

 //===----------------------------------------------------------------------===//
 // String Operations
 //===----------------------------------------------------------------------===//

 std::string StringRef::lower() const {
   std::string Result(size(), char());
   for (size_type i = 0, e = size(); i != e; ++i) {
     Result[i] = ascii_tolower(Data[i]);
   }
   return Result;
 }

 std::string StringRef::upper() const {
   std::string Result(size(), char());
   for (size_type i = 0, e = size(); i != e; ++i) {
     Result[i] = ascii_toupper(Data[i]);
   }
   return Result;
 }

 //===----------------------------------------------------------------------===//
 // String Searching
 //===----------------------------------------------------------------------===//


 /// find - Search for the first string \arg Str in the string.
 ///
 /// \return - The index of the first occurrence of \arg Str, or npos if not
 /// found.
 size_t StringRef::find(StringRef Str, size_t From) const {
   size_t N = Str.size();
   if (N > Length)
     return npos;

   // For short haystacks or unsupported needles fall back to the naive algorithm
   if (Length < 16 || N > 255 || N == 0) {
     for (size_t e = Length - N + 1, i = std::min(From, e); i != e; ++i)
       if (substr(i, N).equals(Str))
         return i;
     return npos;
   }

   if (From >= Length)
     return npos;

   // Build the bad char heuristic table, with uint8_t to reduce cache thrashing.
   uint8_t BadCharSkip[256];
   std::memset(BadCharSkip, N, 256);
   for (unsigned i = 0; i != N-1; ++i)
     BadCharSkip[(uint8_t)Str[i]] = N-1-i;

   unsigned Len = Length-From, Pos = From;
   while (Len >= N) {
     if (substr(Pos, N).equals(Str)) // See if this is the correct substring.
       return Pos;

     // Otherwise skip the appropriate number of bytes.
     uint8_t Skip = BadCharSkip[(uint8_t)(*this)[Pos+N-1]];
     Len -= Skip;
     Pos += Skip;
   }

   return npos;
 }

 /// rfind - Search for the last string \arg Str in the string.
 ///
 /// \return - The index of the last occurrence of \arg Str, or npos if not
 /// found.
 size_t StringRef::rfind(StringRef Str) const {
   size_t N = Str.size();
   if (N > Length)
     return npos;
   for (size_t i = Length - N + 1, e = 0; i != e;) {
     --i;
     if (substr(i, N).equals(Str))
       return i;
   }
   return npos;
 }

 /// find_first_of - Find the first character in the string that is in \arg
 /// Chars, or npos if not found.
 ///
 /// Note: O(size() + Chars.size())
 StringRef::size_type StringRef::find_first_of(StringRef Chars,
                                               size_t From) const {
   std::bitset<1 << CHAR_BIT> CharBits;
   for (size_type i = 0; i != Chars.size(); ++i)
     CharBits.set((unsigned char)Chars[i]);

   for (size_type i = std::min(From, Length), e = Length; i != e; ++i)
     if (CharBits.test((unsigned char)Data[i]))
       return i;
   return npos;
 }

 /// find_first_not_of - Find the first character in the string that is not
 /// \arg C or npos if not found.
 StringRef::size_type StringRef::find_first_not_of(char C, size_t From) const {
   for (size_type i = std::min(From, Length), e = Length; i != e; ++i)
     if (Data[i] != C)
       return i;
   return npos;
 }

 /// find_first_not_of - Find the first character in the string that is not
 /// in the string \arg Chars, or npos if not found.
 ///
 /// Note: O(size() + Chars.size())
 StringRef::size_type StringRef::find_first_not_of(StringRef Chars,
                                                   size_t From) const {
   std::bitset<1 << CHAR_BIT> CharBits;
   for (size_type i = 0; i != Chars.size(); ++i)
     CharBits.set((unsigned char)Chars[i]);

   for (size_type i = std::min(From, Length), e = Length; i != e; ++i)
     if (!CharBits.test((unsigned char)Data[i]))
       return i;
   return npos;
 }

 /// find_last_of - Find the last character in the string that is in \arg C,
 /// or npos if not found.
 ///
 /// Note: O(size() + Chars.size())
 StringRef::size_type StringRef::find_last_of(StringRef Chars,
                                              size_t From) const {
   std::bitset<1 << CHAR_BIT> CharBits;
   for (size_type i = 0; i != Chars.size(); ++i)
     CharBits.set((unsigned char)Chars[i]);

   for (size_type i = std::min(From, Length) - 1, e = -1; i != e; --i)
     if (CharBits.test((unsigned char)Data[i]))
       return i;
   return npos;
 }

 /// find_last_not_of - Find the last character in the string that is not
 /// \arg C, or npos if not found.
 StringRef::size_type StringRef::find_last_not_of(char C, size_t From) const {
   for (size_type i = std::min(From, Length) - 1, e = -1; i != e; --i)
     if (Data[i] != C)
       return i;
   return npos;
 }

 /// find_last_not_of - Find the last character in the string that is not in
 /// \arg Chars, or npos if not found.
 ///
 /// Note: O(size() + Chars.size())
 StringRef::size_type StringRef::find_last_not_of(StringRef Chars,
                                                  size_t From) const {
   std::bitset<1 << CHAR_BIT> CharBits;
   for (size_type i = 0, e = Chars.size(); i != e; ++i)
     CharBits.set((unsigned char)Chars[i]);

   for (size_type i = std::min(From, Length) - 1, e = -1; i != e; --i)
     if (!CharBits.test((unsigned char)Data[i]))
       return i;
   return npos;
 }

 void StringRef::split(SmallVectorImpl<StringRef> &A,
                       StringRef Separators, int MaxSplit,
                       bool KeepEmpty) const {
   StringRef rest = *this;

   // rest.data() is used to distinguish cases like "a," that splits into
   // "a" + "" and "a" that splits into "a" + 0.
   for (int splits = 0;
        rest.data() != nullptr && (MaxSplit < 0 || splits < MaxSplit);
        ++splits) {
     std::pair<StringRef, StringRef> p = rest.split(Separators);

     if (KeepEmpty || p.first.size() != 0)
       A.push_back(p.first);
     rest = p.second;
   }
   // If we have a tail left, add it.
   if (rest.data() != nullptr && (rest.size() != 0 || KeepEmpty))
     A.push_back(rest);
 }

 //===----------------------------------------------------------------------===//
 // Helpful Algorithms
 //===----------------------------------------------------------------------===//

 /// count - Return the number of non-overlapped occurrences of \arg Str in
 /// the string.
 size_t StringRef::count(StringRef Str) const {
   size_t Count = 0;
   size_t N = Str.size();
   if (N > Length)
     return 0;
   for (size_t i = 0, e = Length - N + 1; i != e; ++i)
     if (substr(i, N).equals(Str))
       ++Count;
   return Count;
 }

 static unsigned GetAutoSenseRadix(StringRef &Str) {
   if (Str.startswith("0x")) {
     Str = Str.substr(2);
     return 16;
   }

   if (Str.startswith("0b")) {
     Str = Str.substr(2);
     return 2;
   }

   if (Str.startswith("0o")) {
     Str = Str.substr(2);
     return 8;
   }

   if (Str.startswith("0"))
     return 8;

   return 10;
 }


 /// GetAsUnsignedInteger - Workhorse method that converts a integer character
 /// sequence of radix up to 36 to an unsigned long long value.
 bool llvm::getAsUnsignedInteger(StringRef Str, unsigned Radix,
                                 unsigned long long &Result) {
   // Autosense radix if not specified.
   if (Radix == 0)
     Radix = GetAutoSenseRadix(Str);

   // Empty strings (after the radix autosense) are invalid.
   if (Str.empty()) return true;

   // Parse all the bytes of the string given this radix.  Watch for overflow.
   Result = 0;
   while (!Str.empty()) {
     unsigned CharVal;
     if (Str[0] >= '0' && Str[0] <= '9')
       CharVal = Str[0]-'0';
     else if (Str[0] >= 'a' && Str[0] <= 'z')
       CharVal = Str[0]-'a'+10;
     else if (Str[0] >= 'A' && Str[0] <= 'Z')
       CharVal = Str[0]-'A'+10;
     else
       return true;

     // If the parsed value is larger than the integer radix, the string is
     // invalid.
     if (CharVal >= Radix)
       return true;

     // Add in this character.
     unsigned long long PrevResult = Result;
     Result = Result*Radix+CharVal;

     // Check for overflow by shifting back and seeing if bits were lost.
     if (Result/Radix < PrevResult)
       return true;

     Str = Str.substr(1);
   }

   return false;
 }

 bool llvm::getAsSignedInteger(StringRef Str, unsigned Radix,
                               long long &Result) {
   unsigned long long ULLVal;

   // Handle positive strings first.
   if (Str.empty() || Str.front() != '-') {
     if (getAsUnsignedInteger(Str, Radix, ULLVal) ||
         // Check for value so large it overflows a signed value.
         (long long)ULLVal < 0)
       return true;
     Result = ULLVal;
     return false;
   }

   // Get the positive part of the value.
   if (getAsUnsignedInteger(Str.substr(1), Radix, ULLVal) ||
       // Reject values so large they'd overflow as negative signed, but allow
       // "-0".  This negates the unsigned so that the negative isn't undefined
       // on signed overflow.
       (long long)-ULLVal > 0)
     return true;

   Result = -ULLVal;
   return false;
 }


 // Implementation of StringRef hashing.
 hash_code llvm::hash_value(StringRef S) {
   return hash_combine_range(S.begin(), S.end());
 }
	//===-- StringRef.cpp - Lightweight String References ---------------------===//
	//
	// The LLVM Compiler Infrastructure
	//
	// This file is distributed under the University of Illinois Open Source
	// License. See LICENSE.TXT for details.
	//
	//===----------------------------------------------------------------------===//

	#include "llvm/ADT/StringRef.h"
	#include "llvm/ADT/Hashing.h"
	#include "llvm/ADT/edit_distance.h"
	#include <bitset>
	#include <climits>

	using namespace llvm;

	// MSVC emits references to this into the translation units which reference it.
	#ifndef _MSC_VER
	const size_t StringRef::npos;
	#endif

	static char ascii_tolower(char x) {
	if (x >= 'A' && x <= 'Z')
	return x - 'A' + 'a';
	return x;
	}

	static char ascii_toupper(char x) {
	if (x >= 'a' && x <= 'z')
	return x - 'a' + 'A';
	return x;
	}

	static bool ascii_isdigit(char x) {
	return x >= '0' && x <= '9';
	}

	// strncasecmp() is not available on non-POSIX systems, so define an
	// alternative function here.
	static int ascii_strncasecmp(const char LHS, const char RHS, size_t Length) {
	for (size_t I = 0; I < Length; ++I) {
	unsigned char LHC = ascii_tolower(LHS[I]);
	unsigned char RHC = ascii_tolower(RHS[I]);
	if (LHC != RHC)
	return LHC < RHC ? -1 : 1;
	}
	return 0;
	}

	/// compare_lower - Compare strings, ignoring case.
	int StringRef::compare_lower(StringRef RHS) const {
	if (int Res = ascii_strncasecmp(Data, RHS.Data, std::min(Length, RHS.Length)))
	return Res;
	if (Length == RHS.Length)
	return 0;
	return Length < RHS.Length ? -1 : 1;
	}

	/// Check if this string starts with the given \p Prefix, ignoring case.
	bool StringRef::startswith_lower(StringRef Prefix) const {
	return Length >= Prefix.Length &&
	ascii_strncasecmp(Data, Prefix.Data, Prefix.Length) == 0;
	}

	/// Check if this string ends with the given \p Suffix, ignoring case.
	bool StringRef::endswith_lower(StringRef Suffix) const {
	return Length >= Suffix.Length &&
	ascii_strncasecmp(end() - Suffix.Length, Suffix.Data, Suffix.Length) == 0;
	}

	/// compare_numeric - Compare strings, handle embedded numbers.
	int StringRef::compare_numeric(StringRef RHS) const {
	for (size_t I = 0, E = std::min(Length, RHS.Length); I != E; ++I) {
	// Check for sequences of digits.
	if (ascii_isdigit(Data[I]) && ascii_isdigit(RHS.Data[I])) {
	// The longer sequence of numbers is considered larger.
	// This doesn't really handle prefixed zeros well.
	size_t J;
	for (J = I + 1; J != E + 1; ++J) {
	bool ld = J < Length && ascii_isdigit(Data[J]);
	bool rd = J < RHS.Length && ascii_isdigit(RHS.Data[J]);
	if (ld != rd)
	return rd ? -1 : 1;
	if (!rd)
	break;
	}
	// The two number sequences have the same length (J-I), just memcmp them.
	if (int Res = compareMemory(Data + I, RHS.Data + I, J - I))
	return Res < 0 ? -1 : 1;
	// Identical number sequences, continue search after the numbers.
	I = J - 1;
	continue;
	}
	if (Data[I] != RHS.Data[I])
	return (unsigned char)Data[I] < (unsigned char)RHS.Data[I] ? -1 : 1;
	}
	if (Length == RHS.Length)
	return 0;
	return Length < RHS.Length ? -1 : 1;
	}

	// Compute the edit distance between the two given strings.
	unsigned StringRef::edit_distance(llvm::StringRef Other,
	bool AllowReplacements,
	unsigned MaxEditDistance) const {
	return llvm::ComputeEditDistance(
	makeArrayRef(data(), size()),
	makeArrayRef(Other.data(), Other.size()),
	AllowReplacements, MaxEditDistance);
	}

	//===----------------------------------------------------------------------===//
	// String Operations
	//===----------------------------------------------------------------------===//

	std::string StringRef::lower() const {
	std::string Result(size(), char());
	for (size_type i = 0, e = size(); i != e; ++i) {
	Result[i] = ascii_tolower(Data[i]);
	}
	return Result;
	}

	std::string StringRef::upper() const {
	std::string Result(size(), char());
	for (size_type i = 0, e = size(); i != e; ++i) {
	Result[i] = ascii_toupper(Data[i]);
	}
	return Result;
	}

	//===----------------------------------------------------------------------===//
	// String Searching
	//===----------------------------------------------------------------------===//


	/// find - Search for the first string \arg Str in the string.
	///
	/// \return - The index of the first occurrence of \arg Str, or npos if not
	/// found.
	size_t StringRef::find(StringRef Str, size_t From) const {
	size_t N = Str.size();
	if (N > Length)
	return npos;

	// For short haystacks or unsupported needles fall back to the naive algorithm
	if (Length < 16 \|\| N > 255 \|\| N == 0) {
	for (size_t e = Length - N + 1, i = std::min(From, e); i != e; ++i)
	if (substr(i, N).equals(Str))
	return i;
	return npos;
	}

	if (From >= Length)
	return npos;

	// Build the bad char heuristic table, with uint8_t to reduce cache thrashing.
	uint8_t BadCharSkip[256];
	std::memset(BadCharSkip, N, 256);
	for (unsigned i = 0; i != N-1; ++i)
	BadCharSkip[(uint8_t)Str[i]] = N-1-i;

	unsigned Len = Length-From, Pos = From;
	while (Len >= N) {
	if (substr(Pos, N).equals(Str)) // See if this is the correct substring.
	return Pos;

	// Otherwise skip the appropriate number of bytes.
	uint8_t Skip = BadCharSkip[(uint8_t)(*this)[Pos+N-1]];
	Len -= Skip;
	Pos += Skip;
	}

	return npos;
	}

	/// rfind - Search for the last string \arg Str in the string.
	///
	/// \return - The index of the last occurrence of \arg Str, or npos if not
	/// found.
	size_t StringRef::rfind(StringRef Str) const {
	size_t N = Str.size();
	if (N > Length)
	return npos;
	for (size_t i = Length - N + 1, e = 0; i != e;) {
	--i;
	if (substr(i, N).equals(Str))
	return i;
	}
	return npos;
	}

	/// find_first_of - Find the first character in the string that is in \arg
	/// Chars, or npos if not found.
	///
	/// Note: O(size() + Chars.size())
	StringRef::size_type StringRef::find_first_of(StringRef Chars,
	size_t From) const {
	std::bitset<1 << CHAR_BIT> CharBits;
	for (size_type i = 0; i != Chars.size(); ++i)
	CharBits.set((unsigned char)Chars[i]);

	for (size_type i = std::min(From, Length), e = Length; i != e; ++i)
	if (CharBits.test((unsigned char)Data[i]))
	return i;
	return npos;
	}

	/// find_first_not_of - Find the first character in the string that is not
	/// \arg C or npos if not found.
	StringRef::size_type StringRef::find_first_not_of(char C, size_t From) const {
	for (size_type i = std::min(From, Length), e = Length; i != e; ++i)
	if (Data[i] != C)
	return i;
	return npos;
	}

	/// find_first_not_of - Find the first character in the string that is not
	/// in the string \arg Chars, or npos if not found.
	///
	/// Note: O(size() + Chars.size())
	StringRef::size_type StringRef::find_first_not_of(StringRef Chars,
	size_t From) const {
	std::bitset<1 << CHAR_BIT> CharBits;
	for (size_type i = 0; i != Chars.size(); ++i)
	CharBits.set((unsigned char)Chars[i]);

	for (size_type i = std::min(From, Length), e = Length; i != e; ++i)
	if (!CharBits.test((unsigned char)Data[i]))
	return i;
	return npos;
	}

	/// find_last_of - Find the last character in the string that is in \arg C,
	/// or npos if not found.
	///
	/// Note: O(size() + Chars.size())
	StringRef::size_type StringRef::find_last_of(StringRef Chars,
	size_t From) const {
	std::bitset<1 << CHAR_BIT> CharBits;
	for (size_type i = 0; i != Chars.size(); ++i)
	CharBits.set((unsigned char)Chars[i]);

	for (size_type i = std::min(From, Length) - 1, e = -1; i != e; --i)
	if (CharBits.test((unsigned char)Data[i]))
	return i;
	return npos;
	}

	/// find_last_not_of - Find the last character in the string that is not
	/// \arg C, or npos if not found.
	StringRef::size_type StringRef::find_last_not_of(char C, size_t From) const {
	for (size_type i = std::min(From, Length) - 1, e = -1; i != e; --i)
	if (Data[i] != C)
	return i;
	return npos;
	}

	/// find_last_not_of - Find the last character in the string that is not in
	/// \arg Chars, or npos if not found.
	///
	/// Note: O(size() + Chars.size())
	StringRef::size_type StringRef::find_last_not_of(StringRef Chars,
	size_t From) const {
	std::bitset<1 << CHAR_BIT> CharBits;
	for (size_type i = 0, e = Chars.size(); i != e; ++i)
	CharBits.set((unsigned char)Chars[i]);

	for (size_type i = std::min(From, Length) - 1, e = -1; i != e; --i)
	if (!CharBits.test((unsigned char)Data[i]))
	return i;
	return npos;
	}

	void StringRef::split(SmallVectorImpl<StringRef> &A,
	StringRef Separators, int MaxSplit,
	bool KeepEmpty) const {
	StringRef rest = *this;

	// rest.data() is used to distinguish cases like "a," that splits into
	// "a" + "" and "a" that splits into "a" + 0.
	for (int splits = 0;
	rest.data() != nullptr && (MaxSplit < 0 \|\| splits < MaxSplit);
	++splits) {
	std::pair<StringRef, StringRef> p = rest.split(Separators);

	if (KeepEmpty \|\| p.first.size() != 0)
	A.push_back(p.first);
	rest = p.second;
	}
	// If we have a tail left, add it.
	if (rest.data() != nullptr && (rest.size() != 0 \|\| KeepEmpty))
	A.push_back(rest);
	}

	//===----------------------------------------------------------------------===//
	// Helpful Algorithms
	//===----------------------------------------------------------------------===//

	/// count - Return the number of non-overlapped occurrences of \arg Str in
	/// the string.
	size_t StringRef::count(StringRef Str) const {
	size_t Count = 0;
	size_t N = Str.size();
	if (N > Length)
	return 0;
	for (size_t i = 0, e = Length - N + 1; i != e; ++i)
	if (substr(i, N).equals(Str))
	++Count;
	return Count;
	}

	static unsigned GetAutoSenseRadix(StringRef &Str) {
	if (Str.startswith("0x")) {
	Str = Str.substr(2);
	return 16;
	}

	if (Str.startswith("0b")) {
	Str = Str.substr(2);
	return 2;
	}

	if (Str.startswith("0o")) {
	Str = Str.substr(2);
	return 8;
	}

	if (Str.startswith("0"))
	return 8;

	return 10;
	}


	/// GetAsUnsignedInteger - Workhorse method that converts a integer character
	/// sequence of radix up to 36 to an unsigned long long value.
	bool llvm::getAsUnsignedInteger(StringRef Str, unsigned Radix,
	unsigned long long &Result) {
	// Autosense radix if not specified.
	if (Radix == 0)
	Radix = GetAutoSenseRadix(Str);

	// Empty strings (after the radix autosense) are invalid.
	if (Str.empty()) return true;

	// Parse all the bytes of the string given this radix. Watch for overflow.
	Result = 0;
	while (!Str.empty()) {
	unsigned CharVal;
	if (Str[0] >= '0' && Str[0] <= '9')
	CharVal = Str[0]-'0';
	else if (Str[0] >= 'a' && Str[0] <= 'z')
	CharVal = Str[0]-'a'+10;
	else if (Str[0] >= 'A' && Str[0] <= 'Z')
	CharVal = Str[0]-'A'+10;
	else
	return true;

	// If the parsed value is larger than the integer radix, the string is
	// invalid.
	if (CharVal >= Radix)
	return true;

	// Add in this character.
	unsigned long long PrevResult = Result;
	Result = Result*Radix+CharVal;

	// Check for overflow by shifting back and seeing if bits were lost.
	if (Result/Radix < PrevResult)
	return true;

	Str = Str.substr(1);
	}

	return false;
	}

	bool llvm::getAsSignedInteger(StringRef Str, unsigned Radix,
	long long &Result) {
	unsigned long long ULLVal;

	// Handle positive strings first.
	if (Str.empty() \|\| Str.front() != '-') {
	if (getAsUnsignedInteger(Str, Radix, ULLVal) \|\|
	// Check for value so large it overflows a signed value.
	(long long)ULLVal < 0)
	return true;
	Result = ULLVal;
	return false;
	}

	// Get the positive part of the value.
	if (getAsUnsignedInteger(Str.substr(1), Radix, ULLVal) \|\|
	// Reject values so large they'd overflow as negative signed, but allow
	// "-0". This negates the unsigned so that the negative isn't undefined
	// on signed overflow.
	(long long)-ULLVal > 0)
	return true;

	Result = -ULLVal;
	return false;
	}


	// Implementation of StringRef hashing.
	hash_code llvm::hash_value(StringRef S) {
	return hash_combine_range(S.begin(), S.end());
	}