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			309 lines
		
	
	
		
			9.4 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
			
		
		
	
	
			309 lines
		
	
	
		
			9.4 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
| //===- SubtargetFeature.cpp - CPU characteristics Implementation ----------===//
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| //
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| //                     The LLVM Compiler Infrastructure
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| //
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| // This file is distributed under the University of Illinois Open Source
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| // License. See LICENSE.TXT for details.
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| //
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| //===----------------------------------------------------------------------===//
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| //
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| // This file implements the SubtargetFeature interface.
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| //
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| //===----------------------------------------------------------------------===//
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| 
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| #include "llvm/MC/SubtargetFeature.h"
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| #include "llvm/ADT/StringExtras.h"
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| #include "llvm/Support/Debug.h"
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| #include "llvm/Support/Format.h"
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| #include "llvm/Support/raw_ostream.h"
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| #include <algorithm>
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| #include <cassert>
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| #include <cctype>
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| #include <cstdlib>
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| using namespace llvm;
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| 
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| //===----------------------------------------------------------------------===//
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| //                          Static Helper Functions
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| //===----------------------------------------------------------------------===//
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| 
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| /// hasFlag - Determine if a feature has a flag; '+' or '-'
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| ///
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| static inline bool hasFlag(StringRef Feature) {
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|   assert(!Feature.empty() && "Empty string");
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|   // Get first character
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|   char Ch = Feature[0];
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|   // Check if first character is '+' or '-' flag
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|   return Ch == '+' || Ch =='-';
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| }
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| 
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| /// StripFlag - Return string stripped of flag.
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| ///
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| static inline std::string StripFlag(StringRef Feature) {
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|   return hasFlag(Feature) ? Feature.substr(1) : Feature;
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| }
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| 
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| /// isEnabled - Return true if enable flag; '+'.
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| ///
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| static inline bool isEnabled(StringRef Feature) {
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|   assert(!Feature.empty() && "Empty string");
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|   // Get first character
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|   char Ch = Feature[0];
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|   // Check if first character is '+' for enabled
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|   return Ch == '+';
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| }
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| 
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| /// Split - Splits a string of comma separated items in to a vector of strings.
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| ///
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| static void Split(std::vector<std::string> &V, StringRef S) {
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|   SmallVector<StringRef, 3> Tmp;
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|   S.split(Tmp, ",", -1, false /* KeepEmpty */);
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|   V.assign(Tmp.begin(), Tmp.end());
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| }
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| 
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| /// Adding features.
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| void SubtargetFeatures::AddFeature(StringRef String, bool Enable) {
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|   // Don't add empty features.
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|   if (!String.empty())
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|     // Convert to lowercase, prepend flag if we don't already have a flag.
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|     Features.push_back(hasFlag(String) ? String.lower()
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|                                        : (Enable ? "+" : "-") + String.lower());
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| }
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| 
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| /// Find KV in array using binary search.
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| static const SubtargetFeatureKV *Find(StringRef S,
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|                                       ArrayRef<SubtargetFeatureKV> A) {
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|   // Binary search the array
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|   auto F = std::lower_bound(A.begin(), A.end(), S);
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|   // If not found then return NULL
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|   if (F == A.end() || StringRef(F->Key) != S) return nullptr;
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|   // Return the found array item
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|   return F;
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| }
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| 
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| /// getLongestEntryLength - Return the length of the longest entry in the table.
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| ///
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| static size_t getLongestEntryLength(ArrayRef<SubtargetFeatureKV> Table) {
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|   size_t MaxLen = 0;
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|   for (auto &I : Table)
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|     MaxLen = std::max(MaxLen, std::strlen(I.Key));
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|   return MaxLen;
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| }
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| 
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| /// Display help for feature choices.
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| ///
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| static void Help(ArrayRef<SubtargetFeatureKV> CPUTable,
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|                  ArrayRef<SubtargetFeatureKV> FeatTable) {
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|   // Determine the length of the longest CPU and Feature entries.
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|   unsigned MaxCPULen  = getLongestEntryLength(CPUTable);
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|   unsigned MaxFeatLen = getLongestEntryLength(FeatTable);
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| 
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|   // Print the CPU table.
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|   errs() << "Available CPUs for this target:\n\n";
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|   for (auto &CPU : CPUTable)
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|     errs() << format("  %-*s - %s.\n", MaxCPULen, CPU.Key, CPU.Desc);
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|   errs() << '\n';
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| 
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|   // Print the Feature table.
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|   errs() << "Available features for this target:\n\n";
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|   for (auto &Feature : FeatTable)
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|     errs() << format("  %-*s - %s.\n", MaxFeatLen, Feature.Key, Feature.Desc);
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|   errs() << '\n';
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| 
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|   errs() << "Use +feature to enable a feature, or -feature to disable it.\n"
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|             "For example, llc -mcpu=mycpu -mattr=+feature1,-feature2\n";
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| }
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| 
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| //===----------------------------------------------------------------------===//
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| //                    SubtargetFeatures Implementation
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| //===----------------------------------------------------------------------===//
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| 
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| SubtargetFeatures::SubtargetFeatures(StringRef Initial) {
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|   // Break up string into separate features
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|   Split(Features, Initial);
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| }
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| 
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| 
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| std::string SubtargetFeatures::getString() const {
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|   return join(Features.begin(), Features.end(), ",");
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| }
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| 
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| /// SetImpliedBits - For each feature that is (transitively) implied by this
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| /// feature, set it.
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| ///
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| static
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| void SetImpliedBits(FeatureBitset &Bits, const SubtargetFeatureKV *FeatureEntry,
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|                     ArrayRef<SubtargetFeatureKV> FeatureTable) {
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|   for (auto &FE : FeatureTable) {
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|     if (FeatureEntry->Value == FE.Value) continue;
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| 
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|     if ((FeatureEntry->Implies & FE.Value).any()) {
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|       Bits |= FE.Value;
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|       SetImpliedBits(Bits, &FE, FeatureTable);
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|     }
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|   }
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| }
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| 
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| /// ClearImpliedBits - For each feature that (transitively) implies this
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| /// feature, clear it.
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| ///
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| static
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| void ClearImpliedBits(FeatureBitset &Bits, 
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|                       const SubtargetFeatureKV *FeatureEntry,
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|                       ArrayRef<SubtargetFeatureKV> FeatureTable) {
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|   for (auto &FE : FeatureTable) {
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|     if (FeatureEntry->Value == FE.Value) continue;
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| 
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|     if ((FE.Implies & FeatureEntry->Value).any()) {
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|       Bits &= ~FE.Value;
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|       ClearImpliedBits(Bits, &FE, FeatureTable);
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|     }
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|   }
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| }
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| 
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| /// ToggleFeature - Toggle a feature and returns the newly updated feature
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| /// bits.
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| FeatureBitset
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| SubtargetFeatures::ToggleFeature(FeatureBitset Bits, StringRef Feature,
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|                                  ArrayRef<SubtargetFeatureKV> FeatureTable) {
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| 
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|   // Find feature in table.
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|   const SubtargetFeatureKV *FeatureEntry =
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|       Find(StripFlag(Feature), FeatureTable);
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|   // If there is a match
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|   if (FeatureEntry) {
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|     if ((Bits & FeatureEntry->Value) == FeatureEntry->Value) {
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|       Bits &= ~FeatureEntry->Value;
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|       // For each feature that implies this, clear it.
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|       ClearImpliedBits(Bits, FeatureEntry, FeatureTable);
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|     } else {
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|       Bits |=  FeatureEntry->Value;
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| 
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|       // For each feature that this implies, set it.
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|       SetImpliedBits(Bits, FeatureEntry, FeatureTable);
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|     }
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|   } else {
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|     errs() << "'" << Feature
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|            << "' is not a recognized feature for this target"
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|            << " (ignoring feature)\n";
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|   }
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| 
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|   return Bits;
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| }
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| 
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| 
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| /// getFeatureBits - Get feature bits a CPU.
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| ///
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| FeatureBitset
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| SubtargetFeatures::getFeatureBits(StringRef CPU,
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|                                   ArrayRef<SubtargetFeatureKV> CPUTable,
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|                                   ArrayRef<SubtargetFeatureKV> FeatureTable) {
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| 
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|   if (CPUTable.empty() || FeatureTable.empty())
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|     return FeatureBitset();
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| 
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| #ifndef NDEBUG
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|   for (size_t i = 1, e = CPUTable.size(); i != e; ++i) {
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|     assert(strcmp(CPUTable[i - 1].Key, CPUTable[i].Key) < 0 &&
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|            "CPU table is not sorted");
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|   }
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|   for (size_t i = 1, e = FeatureTable.size(); i != e; ++i) {
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|     assert(strcmp(FeatureTable[i - 1].Key, FeatureTable[i].Key) < 0 &&
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|           "CPU features table is not sorted");
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|   }
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| #endif
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|   // Resulting bits
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|   FeatureBitset Bits;
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| 
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|   // Check if help is needed
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|   if (CPU == "help")
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|     Help(CPUTable, FeatureTable);
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| 
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|   // Find CPU entry if CPU name is specified.
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|   else if (!CPU.empty()) {
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|     const SubtargetFeatureKV *CPUEntry = Find(CPU, CPUTable);
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| 
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|     // If there is a match
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|     if (CPUEntry) {
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|       // Set base feature bits
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|       Bits = CPUEntry->Value;
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| 
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|       // Set the feature implied by this CPU feature, if any.
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|       for (auto &FE : FeatureTable) {
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|         if ((CPUEntry->Value & FE.Value).any())
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|           SetImpliedBits(Bits, &FE, FeatureTable);
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|       }
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|     } else {
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|       errs() << "'" << CPU
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|              << "' is not a recognized processor for this target"
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|              << " (ignoring processor)\n";
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|     }
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|   }
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| 
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|   // Iterate through each feature
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|   for (auto &Feature : Features) {
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|     // Check for help
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|     if (Feature == "+help")
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|       Help(CPUTable, FeatureTable);
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| 
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|     // Find feature in table.
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|     const SubtargetFeatureKV *FeatureEntry =
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|         Find(StripFlag(Feature), FeatureTable);
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|     // If there is a match
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|     if (FeatureEntry) {
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|       // Enable/disable feature in bits
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|       if (isEnabled(Feature)) {
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|         Bits |=  FeatureEntry->Value;
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| 
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|         // For each feature that this implies, set it.
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|         SetImpliedBits(Bits, FeatureEntry, FeatureTable);
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|       } else {
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|         Bits &= ~FeatureEntry->Value;
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| 
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|         // For each feature that implies this, clear it.
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|         ClearImpliedBits(Bits, FeatureEntry, FeatureTable);
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|       }
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|     } else {
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|       errs() << "'" << Feature
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|              << "' is not a recognized feature for this target"
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|              << " (ignoring feature)\n";
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|     }
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|   }
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| 
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|   return Bits;
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| }
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| 
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| /// print - Print feature string.
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| ///
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| void SubtargetFeatures::print(raw_ostream &OS) const {
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|   for (auto &F : Features)
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|     OS << F << " ";
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|   OS << "\n";
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| }
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| 
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| #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
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| /// dump - Dump feature info.
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| ///
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| void SubtargetFeatures::dump() const {
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|   print(dbgs());
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| }
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| #endif
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| 
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| /// Adds the default features for the specified target triple.
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| ///
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| /// FIXME: This is an inelegant way of specifying the features of a
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| /// subtarget. It would be better if we could encode this information
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| /// into the IR. See <rdar://5972456>.
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| ///
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| void SubtargetFeatures::getDefaultSubtargetFeatures(const Triple& Triple) {
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|   if (Triple.getVendor() == Triple::Apple) {
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|     if (Triple.getArch() == Triple::ppc) {
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|       // powerpc-apple-*
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|       AddFeature("altivec");
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|     } else if (Triple.getArch() == Triple::ppc64) {
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|       // powerpc64-apple-*
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|       AddFeature("64bit");
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|       AddFeature("altivec");
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|     }
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|   }
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| }
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