third_party/LLVM/lib/MC/SubtargetFeature.cpp - SwiftShader - Git at Google

 //===- SubtargetFeature.cpp - CPU characteristics Implementation ----------===//
 //
 //                     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 SubtargetFeature interface.
 //
 //===----------------------------------------------------------------------===//

 #include "llvm/MC/SubtargetFeature.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/raw_ostream.h"
 #include "llvm/ADT/StringExtras.h"
 #include <algorithm>
 #include <cassert>
 #include <cctype>
 #include <cstdlib>
 using namespace llvm;

 //===----------------------------------------------------------------------===//
 //                          Static Helper Functions
 //===----------------------------------------------------------------------===//

 /// hasFlag - Determine if a feature has a flag; '+' or '-'
 ///
 static inline bool hasFlag(const StringRef Feature) {
   assert(!Feature.empty() && "Empty string");
   // Get first character
   char Ch = Feature[0];
   // Check if first character is '+' or '-' flag
   return Ch == '+' || Ch =='-';
 }

 /// StripFlag - Return string stripped of flag.
 ///
 static inline std::string StripFlag(const StringRef Feature) {
   return hasFlag(Feature) ? Feature.substr(1) : Feature;
 }

 /// isEnabled - Return true if enable flag; '+'.
 ///
 static inline bool isEnabled(const StringRef Feature) {
   assert(!Feature.empty() && "Empty string");
   // Get first character
   char Ch = Feature[0];
   // Check if first character is '+' for enabled
   return Ch == '+';
 }

 /// PrependFlag - Return a string with a prepended flag; '+' or '-'.
 ///
 static inline std::string PrependFlag(const StringRef Feature,
                                     bool IsEnabled) {
   assert(!Feature.empty() && "Empty string");
   if (hasFlag(Feature))
     return Feature;
   std::string Prefix = IsEnabled ? "+" : "-";
   Prefix += Feature;
   return Prefix;
 }

 /// Split - Splits a string of comma separated items in to a vector of strings.
 ///
 static void Split(std::vector<std::string> &V, const StringRef S) {
   if (S.empty())
     return;

   // Start at beginning of string.
   size_t Pos = 0;
   while (true) {
     // Find the next comma
     size_t Comma = S.find(',', Pos);
     // If no comma found then the rest of the string is used
     if (Comma == std::string::npos) {
       // Add string to vector
       V.push_back(S.substr(Pos));
       break;
     }
     // Otherwise add substring to vector
     V.push_back(S.substr(Pos, Comma - Pos));
     // Advance to next item
     Pos = Comma + 1;
   }
 }

 /// Join a vector of strings to a string with a comma separating each element.
 ///
 static std::string Join(const std::vector<std::string> &V) {
   // Start with empty string.
   std::string Result;
   // If the vector is not empty
   if (!V.empty()) {
     // Start with the first feature
     Result = V[0];
     // For each successive feature
     for (size_t i = 1; i < V.size(); i++) {
       // Add a comma
       Result += ",";
       // Add the feature
       Result += V[i];
     }
   }
   // Return the features string
   return Result;
 }

 /// Adding features.
 void SubtargetFeatures::AddFeature(const StringRef String,
                                    bool IsEnabled) {
   // Don't add empty features
   if (!String.empty()) {
     // Convert to lowercase, prepend flag and add to vector
     Features.push_back(PrependFlag(LowercaseString(String), IsEnabled));
   }
 }

 /// Find KV in array using binary search.
 template<typename T> const T *Find(const StringRef S, const T *A, size_t L) {
   // Make the lower bound element we're looking for
   T KV;
   KV.Key = S.data();
   // Determine the end of the array
   const T *Hi = A + L;
   // Binary search the array
   const T *F = std::lower_bound(A, Hi, KV);
   // If not found then return NULL
   if (F == Hi || StringRef(F->Key) != S) return NULL;
   // Return the found array item
   return F;
 }

 /// getLongestEntryLength - Return the length of the longest entry in the table.
 ///
 static size_t getLongestEntryLength(const SubtargetFeatureKV *Table,
                                     size_t Size) {
   size_t MaxLen = 0;
   for (size_t i = 0; i < Size; i++)
     MaxLen = std::max(MaxLen, std::strlen(Table[i].Key));
   return MaxLen;
 }

 /// Display help for feature choices.
 ///
 static void Help(const SubtargetFeatureKV *CPUTable, size_t CPUTableSize,
                  const SubtargetFeatureKV *FeatTable, size_t FeatTableSize) {
   // Determine the length of the longest CPU and Feature entries.
   unsigned MaxCPULen  = getLongestEntryLength(CPUTable, CPUTableSize);
   unsigned MaxFeatLen = getLongestEntryLength(FeatTable, FeatTableSize);

   // Print the CPU table.
   errs() << "Available CPUs for this target:\n\n";
   for (size_t i = 0; i != CPUTableSize; i++)
     errs() << "  " << CPUTable[i].Key
          << std::string(MaxCPULen - std::strlen(CPUTable[i].Key), ' ')
          << " - " << CPUTable[i].Desc << ".\n";
   errs() << "\n";

   // Print the Feature table.
   errs() << "Available features for this target:\n\n";
   for (size_t i = 0; i != FeatTableSize; i++)
     errs() << "  " << FeatTable[i].Key
          << std::string(MaxFeatLen - std::strlen(FeatTable[i].Key), ' ')
          << " - " << FeatTable[i].Desc << ".\n";
   errs() << "\n";

   errs() << "Use +feature to enable a feature, or -feature to disable it.\n"
        << "For example, llc -mcpu=mycpu -mattr=+feature1,-feature2\n";
   std::exit(1);
 }

 //===----------------------------------------------------------------------===//
 //                    SubtargetFeatures Implementation
 //===----------------------------------------------------------------------===//

 SubtargetFeatures::SubtargetFeatures(const StringRef Initial) {
   // Break up string into separate features
   Split(Features, Initial);
 }


 std::string SubtargetFeatures::getString() const {
   return Join(Features);
 }

 /// SetImpliedBits - For each feature that is (transitively) implied by this
 /// feature, set it.
 ///
 static
 void SetImpliedBits(uint64_t &Bits, const SubtargetFeatureKV *FeatureEntry,
                     const SubtargetFeatureKV *FeatureTable,
                     size_t FeatureTableSize) {
   for (size_t i = 0; i < FeatureTableSize; ++i) {
     const SubtargetFeatureKV &FE = FeatureTable[i];

     if (FeatureEntry->Value == FE.Value) continue;

     if (FeatureEntry->Implies & FE.Value) {
       Bits |= FE.Value;
       SetImpliedBits(Bits, &FE, FeatureTable, FeatureTableSize);
     }
   }
 }

 /// ClearImpliedBits - For each feature that (transitively) implies this
 /// feature, clear it.
 ///
 static
 void ClearImpliedBits(uint64_t &Bits, const SubtargetFeatureKV *FeatureEntry,
                       const SubtargetFeatureKV *FeatureTable,
                       size_t FeatureTableSize) {
   for (size_t i = 0; i < FeatureTableSize; ++i) {
     const SubtargetFeatureKV &FE = FeatureTable[i];

     if (FeatureEntry->Value == FE.Value) continue;

     if (FE.Implies & FeatureEntry->Value) {
       Bits &= ~FE.Value;
       ClearImpliedBits(Bits, &FE, FeatureTable, FeatureTableSize);
     }
   }
 }

 /// ToggleFeature - Toggle a feature and returns the newly updated feature
 /// bits.
 uint64_t
 SubtargetFeatures::ToggleFeature(uint64_t Bits, const StringRef Feature,
                                  const SubtargetFeatureKV *FeatureTable,
                                  size_t FeatureTableSize) {
   // Find feature in table.
   const SubtargetFeatureKV *FeatureEntry =
     Find(StripFlag(Feature), FeatureTable, FeatureTableSize);
   // If there is a match
   if (FeatureEntry) {
     if ((Bits & FeatureEntry->Value) == FeatureEntry->Value) {
       Bits &= ~FeatureEntry->Value;

       // For each feature that implies this, clear it.
       ClearImpliedBits(Bits, FeatureEntry, FeatureTable, FeatureTableSize);
     } else {
       Bits |=  FeatureEntry->Value;

       // For each feature that this implies, set it.
       SetImpliedBits(Bits, FeatureEntry, FeatureTable, FeatureTableSize);
     }
   } else {
     errs() << "'" << Feature
            << "' is not a recognized feature for this target"
            << " (ignoring feature)\n";
   }

   return Bits;
 }


 /// getFeatureBits - Get feature bits a CPU.
 ///
 uint64_t SubtargetFeatures::getFeatureBits(const StringRef CPU,
                                          const SubtargetFeatureKV *CPUTable,
                                          size_t CPUTableSize,
                                          const SubtargetFeatureKV *FeatureTable,
                                          size_t FeatureTableSize) {
   if (!FeatureTableSize || !CPUTableSize)
     return 0;

 #ifndef NDEBUG
   for (size_t i = 1; i < CPUTableSize; i++) {
     assert(strcmp(CPUTable[i - 1].Key, CPUTable[i].Key) < 0 &&
            "CPU table is not sorted");
   }
   for (size_t i = 1; i < FeatureTableSize; i++) {
     assert(strcmp(FeatureTable[i - 1].Key, FeatureTable[i].Key) < 0 &&
           "CPU features table is not sorted");
   }
 #endif
   uint64_t Bits = 0;                    // Resulting bits

   // Check if help is needed
   if (CPU == "help")
     Help(CPUTable, CPUTableSize, FeatureTable, FeatureTableSize);

   // Find CPU entry if CPU name is specified.
   if (!CPU.empty()) {
     const SubtargetFeatureKV *CPUEntry = Find(CPU, CPUTable, CPUTableSize);
     // If there is a match
     if (CPUEntry) {
       // Set base feature bits
       Bits = CPUEntry->Value;

       // Set the feature implied by this CPU feature, if any.
       for (size_t i = 0; i < FeatureTableSize; ++i) {
         const SubtargetFeatureKV &FE = FeatureTable[i];
         if (CPUEntry->Value & FE.Value)
           SetImpliedBits(Bits, &FE, FeatureTable, FeatureTableSize);
       }
     } else {
       errs() << "'" << CPU
              << "' is not a recognized processor for this target"
              << " (ignoring processor)\n";
     }
   }

   // Iterate through each feature
   for (size_t i = 0, E = Features.size(); i < E; i++) {
     const StringRef Feature = Features[i];

     // Check for help
     if (Feature == "+help")
       Help(CPUTable, CPUTableSize, FeatureTable, FeatureTableSize);

     // Find feature in table.
     const SubtargetFeatureKV *FeatureEntry =
                        Find(StripFlag(Feature), FeatureTable, FeatureTableSize);
     // If there is a match
     if (FeatureEntry) {
       // Enable/disable feature in bits
       if (isEnabled(Feature)) {
         Bits |=  FeatureEntry->Value;

         // For each feature that this implies, set it.
         SetImpliedBits(Bits, FeatureEntry, FeatureTable, FeatureTableSize);
       } else {
         Bits &= ~FeatureEntry->Value;

         // For each feature that implies this, clear it.
         ClearImpliedBits(Bits, FeatureEntry, FeatureTable, FeatureTableSize);
       }
     } else {
       errs() << "'" << Feature
              << "' is not a recognized feature for this target"
              << " (ignoring feature)\n";
     }
   }

   return Bits;
 }

 /// Get scheduling itinerary of a CPU.
 void *SubtargetFeatures::getItinerary(const StringRef CPU,
                                       const SubtargetInfoKV *Table,
                                       size_t TableSize) {
   assert(Table && "missing table");
 #ifndef NDEBUG
   for (size_t i = 1; i < TableSize; i++) {
     assert(strcmp(Table[i - 1].Key, Table[i].Key) < 0 && "Table is not sorted");
   }
 #endif

   // Find entry
   const SubtargetInfoKV *Entry = Find(CPU, Table, TableSize);

   if (Entry) {
     return Entry->Value;
   } else {
     errs() << "'" << CPU
            << "' is not a recognized processor for this target"
            << " (ignoring processor)\n";
     return NULL;
   }
 }

 /// print - Print feature string.
 ///
 void SubtargetFeatures::print(raw_ostream &OS) const {
   for (size_t i = 0, e = Features.size(); i != e; ++i)
     OS << Features[i] << "  ";
   OS << "\n";
 }

 /// dump - Dump feature info.
 ///
 void SubtargetFeatures::dump() const {
   print(dbgs());
 }

 /// getDefaultSubtargetFeatures - Return a string listing the features
 /// associated with the target triple.
 ///
 /// FIXME: This is an inelegant way of specifying the features of a
 /// subtarget. It would be better if we could encode this information
 /// into the IR. See <rdar://5972456>.
 ///
 void SubtargetFeatures::getDefaultSubtargetFeatures(const Triple& Triple) {
   if (Triple.getVendor() == Triple::Apple) {
     if (Triple.getArch() == Triple::ppc) {
       // powerpc-apple-*
       AddFeature("altivec");
     } else if (Triple.getArch() == Triple::ppc64) {
       // powerpc64-apple-*
       AddFeature("64bit");
       AddFeature("altivec");
     }
   }
 }
	//===- SubtargetFeature.cpp - CPU characteristics Implementation ----------===//
	//
	// 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 SubtargetFeature interface.
	//
	//===----------------------------------------------------------------------===//

	#include "llvm/MC/SubtargetFeature.h"
	#include "llvm/Support/Debug.h"
	#include "llvm/Support/raw_ostream.h"
	#include "llvm/ADT/StringExtras.h"
	#include <algorithm>
	#include <cassert>
	#include <cctype>
	#include <cstdlib>
	using namespace llvm;

	//===----------------------------------------------------------------------===//
	// Static Helper Functions
	//===----------------------------------------------------------------------===//

	/// hasFlag - Determine if a feature has a flag; '+' or '-'
	///
	static inline bool hasFlag(const StringRef Feature) {
	assert(!Feature.empty() && "Empty string");
	// Get first character
	char Ch = Feature[0];
	// Check if first character is '+' or '-' flag
	return Ch == '+' \|\| Ch =='-';
	}

	/// StripFlag - Return string stripped of flag.
	///
	static inline std::string StripFlag(const StringRef Feature) {
	return hasFlag(Feature) ? Feature.substr(1) : Feature;
	}

	/// isEnabled - Return true if enable flag; '+'.
	///
	static inline bool isEnabled(const StringRef Feature) {
	assert(!Feature.empty() && "Empty string");
	// Get first character
	char Ch = Feature[0];
	// Check if first character is '+' for enabled
	return Ch == '+';
	}

	/// PrependFlag - Return a string with a prepended flag; '+' or '-'.
	///
	static inline std::string PrependFlag(const StringRef Feature,
	bool IsEnabled) {
	assert(!Feature.empty() && "Empty string");
	if (hasFlag(Feature))
	return Feature;
	std::string Prefix = IsEnabled ? "+" : "-";
	Prefix += Feature;
	return Prefix;
	}

	/// Split - Splits a string of comma separated items in to a vector of strings.
	///
	static void Split(std::vector<std::string> &V, const StringRef S) {
	if (S.empty())
	return;

	// Start at beginning of string.
	size_t Pos = 0;
	while (true) {
	// Find the next comma
	size_t Comma = S.find(',', Pos);
	// If no comma found then the rest of the string is used
	if (Comma == std::string::npos) {
	// Add string to vector
	V.push_back(S.substr(Pos));
	break;
	}
	// Otherwise add substring to vector
	V.push_back(S.substr(Pos, Comma - Pos));
	// Advance to next item
	Pos = Comma + 1;
	}
	}

	/// Join a vector of strings to a string with a comma separating each element.
	///
	static std::string Join(const std::vector<std::string> &V) {
	// Start with empty string.
	std::string Result;
	// If the vector is not empty
	if (!V.empty()) {
	// Start with the first feature
	Result = V[0];
	// For each successive feature
	for (size_t i = 1; i < V.size(); i++) {
	// Add a comma
	Result += ",";
	// Add the feature
	Result += V[i];
	}
	}
	// Return the features string
	return Result;
	}

	/// Adding features.
	void SubtargetFeatures::AddFeature(const StringRef String,
	bool IsEnabled) {
	// Don't add empty features
	if (!String.empty()) {
	// Convert to lowercase, prepend flag and add to vector
	Features.push_back(PrependFlag(LowercaseString(String), IsEnabled));
	}
	}

	/// Find KV in array using binary search.
	template<typename T> const T Find(const StringRef S, const T A, size_t L) {
	// Make the lower bound element we're looking for
	T KV;
	KV.Key = S.data();
	// Determine the end of the array
	const T *Hi = A + L;
	// Binary search the array
	const T *F = std::lower_bound(A, Hi, KV);
	// If not found then return NULL
	if (F == Hi \|\| StringRef(F->Key) != S) return NULL;
	// Return the found array item
	return F;
	}

	/// getLongestEntryLength - Return the length of the longest entry in the table.
	///
	static size_t getLongestEntryLength(const SubtargetFeatureKV *Table,
	size_t Size) {
	size_t MaxLen = 0;
	for (size_t i = 0; i < Size; i++)
	MaxLen = std::max(MaxLen, std::strlen(Table[i].Key));
	return MaxLen;
	}

	/// Display help for feature choices.
	///
	static void Help(const SubtargetFeatureKV *CPUTable, size_t CPUTableSize,
	const SubtargetFeatureKV *FeatTable, size_t FeatTableSize) {
	// Determine the length of the longest CPU and Feature entries.
	unsigned MaxCPULen = getLongestEntryLength(CPUTable, CPUTableSize);
	unsigned MaxFeatLen = getLongestEntryLength(FeatTable, FeatTableSize);

	// Print the CPU table.
	errs() << "Available CPUs for this target:\n\n";
	for (size_t i = 0; i != CPUTableSize; i++)
	errs() << " " << CPUTable[i].Key
	<< std::string(MaxCPULen - std::strlen(CPUTable[i].Key), ' ')
	<< " - " << CPUTable[i].Desc << ".\n";
	errs() << "\n";

	// Print the Feature table.
	errs() << "Available features for this target:\n\n";
	for (size_t i = 0; i != FeatTableSize; i++)
	errs() << " " << FeatTable[i].Key
	<< std::string(MaxFeatLen - std::strlen(FeatTable[i].Key), ' ')
	<< " - " << FeatTable[i].Desc << ".\n";
	errs() << "\n";

	errs() << "Use +feature to enable a feature, or -feature to disable it.\n"
	<< "For example, llc -mcpu=mycpu -mattr=+feature1,-feature2\n";
	std::exit(1);
	}

	//===----------------------------------------------------------------------===//
	// SubtargetFeatures Implementation
	//===----------------------------------------------------------------------===//

	SubtargetFeatures::SubtargetFeatures(const StringRef Initial) {
	// Break up string into separate features
	Split(Features, Initial);
	}


	std::string SubtargetFeatures::getString() const {
	return Join(Features);
	}

	/// SetImpliedBits - For each feature that is (transitively) implied by this
	/// feature, set it.
	///
	static
	void SetImpliedBits(uint64_t &Bits, const SubtargetFeatureKV *FeatureEntry,
	const SubtargetFeatureKV *FeatureTable,
	size_t FeatureTableSize) {
	for (size_t i = 0; i < FeatureTableSize; ++i) {
	const SubtargetFeatureKV &FE = FeatureTable[i];

	if (FeatureEntry->Value == FE.Value) continue;

	if (FeatureEntry->Implies & FE.Value) {
	Bits \|= FE.Value;
	SetImpliedBits(Bits, &FE, FeatureTable, FeatureTableSize);
	}
	}
	}

	/// ClearImpliedBits - For each feature that (transitively) implies this
	/// feature, clear it.
	///
	static
	void ClearImpliedBits(uint64_t &Bits, const SubtargetFeatureKV *FeatureEntry,
	const SubtargetFeatureKV *FeatureTable,
	size_t FeatureTableSize) {
	for (size_t i = 0; i < FeatureTableSize; ++i) {
	const SubtargetFeatureKV &FE = FeatureTable[i];

	if (FeatureEntry->Value == FE.Value) continue;

	if (FE.Implies & FeatureEntry->Value) {
	Bits &= ~FE.Value;
	ClearImpliedBits(Bits, &FE, FeatureTable, FeatureTableSize);
	}
	}
	}

	/// ToggleFeature - Toggle a feature and returns the newly updated feature
	/// bits.
	uint64_t
	SubtargetFeatures::ToggleFeature(uint64_t Bits, const StringRef Feature,
	const SubtargetFeatureKV *FeatureTable,
	size_t FeatureTableSize) {
	// Find feature in table.
	const SubtargetFeatureKV *FeatureEntry =
	Find(StripFlag(Feature), FeatureTable, FeatureTableSize);
	// If there is a match
	if (FeatureEntry) {
	if ((Bits & FeatureEntry->Value) == FeatureEntry->Value) {
	Bits &= ~FeatureEntry->Value;

	// For each feature that implies this, clear it.
	ClearImpliedBits(Bits, FeatureEntry, FeatureTable, FeatureTableSize);
	} else {
	Bits \|= FeatureEntry->Value;

	// For each feature that this implies, set it.
	SetImpliedBits(Bits, FeatureEntry, FeatureTable, FeatureTableSize);
	}
	} else {
	errs() << "'" << Feature
	<< "' is not a recognized feature for this target"
	<< " (ignoring feature)\n";
	}

	return Bits;
	}


	/// getFeatureBits - Get feature bits a CPU.
	///
	uint64_t SubtargetFeatures::getFeatureBits(const StringRef CPU,
	const SubtargetFeatureKV *CPUTable,
	size_t CPUTableSize,
	const SubtargetFeatureKV *FeatureTable,
	size_t FeatureTableSize) {
	if (!FeatureTableSize \|\| !CPUTableSize)
	return 0;

	#ifndef NDEBUG
	for (size_t i = 1; i < CPUTableSize; i++) {
	assert(strcmp(CPUTable[i - 1].Key, CPUTable[i].Key) < 0 &&
	"CPU table is not sorted");
	}
	for (size_t i = 1; i < FeatureTableSize; i++) {
	assert(strcmp(FeatureTable[i - 1].Key, FeatureTable[i].Key) < 0 &&
	"CPU features table is not sorted");
	}
	#endif
	uint64_t Bits = 0; // Resulting bits

	// Check if help is needed
	if (CPU == "help")
	Help(CPUTable, CPUTableSize, FeatureTable, FeatureTableSize);

	// Find CPU entry if CPU name is specified.
	if (!CPU.empty()) {
	const SubtargetFeatureKV *CPUEntry = Find(CPU, CPUTable, CPUTableSize);
	// If there is a match
	if (CPUEntry) {
	// Set base feature bits
	Bits = CPUEntry->Value;

	// Set the feature implied by this CPU feature, if any.
	for (size_t i = 0; i < FeatureTableSize; ++i) {
	const SubtargetFeatureKV &FE = FeatureTable[i];
	if (CPUEntry->Value & FE.Value)
	SetImpliedBits(Bits, &FE, FeatureTable, FeatureTableSize);
	}
	} else {
	errs() << "'" << CPU
	<< "' is not a recognized processor for this target"
	<< " (ignoring processor)\n";
	}
	}

	// Iterate through each feature
	for (size_t i = 0, E = Features.size(); i < E; i++) {
	const StringRef Feature = Features[i];

	// Check for help
	if (Feature == "+help")
	Help(CPUTable, CPUTableSize, FeatureTable, FeatureTableSize);

	// Find feature in table.
	const SubtargetFeatureKV *FeatureEntry =
	Find(StripFlag(Feature), FeatureTable, FeatureTableSize);
	// If there is a match
	if (FeatureEntry) {
	// Enable/disable feature in bits
	if (isEnabled(Feature)) {
	Bits \|= FeatureEntry->Value;

	// For each feature that this implies, set it.
	SetImpliedBits(Bits, FeatureEntry, FeatureTable, FeatureTableSize);
	} else {
	Bits &= ~FeatureEntry->Value;

	// For each feature that implies this, clear it.
	ClearImpliedBits(Bits, FeatureEntry, FeatureTable, FeatureTableSize);
	}
	} else {
	errs() << "'" << Feature
	<< "' is not a recognized feature for this target"
	<< " (ignoring feature)\n";
	}
	}

	return Bits;
	}

	/// Get scheduling itinerary of a CPU.
	void *SubtargetFeatures::getItinerary(const StringRef CPU,
	const SubtargetInfoKV *Table,
	size_t TableSize) {
	assert(Table && "missing table");
	#ifndef NDEBUG
	for (size_t i = 1; i < TableSize; i++) {
	assert(strcmp(Table[i - 1].Key, Table[i].Key) < 0 && "Table is not sorted");
	}
	#endif

	// Find entry
	const SubtargetInfoKV *Entry = Find(CPU, Table, TableSize);

	if (Entry) {
	return Entry->Value;
	} else {
	errs() << "'" << CPU
	<< "' is not a recognized processor for this target"
	<< " (ignoring processor)\n";
	return NULL;
	}
	}

	/// print - Print feature string.
	///
	void SubtargetFeatures::print(raw_ostream &OS) const {
	for (size_t i = 0, e = Features.size(); i != e; ++i)
	OS << Features[i] << " ";
	OS << "\n";
	}

	/// dump - Dump feature info.
	///
	void SubtargetFeatures::dump() const {
	print(dbgs());
	}

	/// getDefaultSubtargetFeatures - Return a string listing the features
	/// associated with the target triple.
	///
	/// FIXME: This is an inelegant way of specifying the features of a
	/// subtarget. It would be better if we could encode this information
	/// into the IR. See <rdar://5972456>.
	///
	void SubtargetFeatures::getDefaultSubtargetFeatures(const Triple& Triple) {
	if (Triple.getVendor() == Triple::Apple) {
	if (Triple.getArch() == Triple::ppc) {
	// powerpc-apple-*
	AddFeature("altivec");
	} else if (Triple.getArch() == Triple::ppc64) {
	// powerpc64-apple-*
	AddFeature("64bit");
	AddFeature("altivec");
	}
	}
	}