1 //===- SubtargetFeature.cpp - CPU characteristics Implementation ----------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file implements the SubtargetFeature interface.
12 //===----------------------------------------------------------------------===//
14 #include "llvm/MC/SubtargetFeature.h"
15 #include "llvm/ADT/StringExtras.h"
16 #include "llvm/Support/Debug.h"
17 #include "llvm/Support/Format.h"
18 #include "llvm/Support/raw_ostream.h"
25 //===----------------------------------------------------------------------===//
26 // Static Helper Functions
27 //===----------------------------------------------------------------------===//
29 /// hasFlag - Determine if a feature has a flag; '+' or '-'
31 static inline bool hasFlag(StringRef Feature) {
32 assert(!Feature.empty() && "Empty string");
33 // Get first character
35 // Check if first character is '+' or '-' flag
36 return Ch == '+' || Ch =='-';
39 /// StripFlag - Return string stripped of flag.
41 static inline std::string StripFlag(StringRef Feature) {
42 return hasFlag(Feature) ? Feature.substr(1) : Feature;
45 /// isEnabled - Return true if enable flag; '+'.
47 static inline bool isEnabled(StringRef Feature) {
48 assert(!Feature.empty() && "Empty string");
49 // Get first character
51 // Check if first character is '+' for enabled
55 /// Split - Splits a string of comma separated items in to a vector of strings.
57 static void Split(std::vector<std::string> &V, StringRef S) {
58 SmallVector<StringRef, 3> Tmp;
59 S.split(Tmp, ',', -1, false /* KeepEmpty */);
60 V.assign(Tmp.begin(), Tmp.end());
64 void SubtargetFeatures::AddFeature(StringRef String, bool Enable) {
65 // Don't add empty features.
67 // Convert to lowercase, prepend flag if we don't already have a flag.
68 Features.push_back(hasFlag(String) ? String.lower()
69 : (Enable ? "+" : "-") + String.lower());
72 /// Find KV in array using binary search.
73 static const SubtargetFeatureKV *Find(StringRef S,
74 ArrayRef<SubtargetFeatureKV> A) {
75 // Binary search the array
76 auto F = std::lower_bound(A.begin(), A.end(), S);
77 // If not found then return NULL
78 if (F == A.end() || StringRef(F->Key) != S) return nullptr;
79 // Return the found array item
83 /// getLongestEntryLength - Return the length of the longest entry in the table.
85 static size_t getLongestEntryLength(ArrayRef<SubtargetFeatureKV> Table) {
88 MaxLen = std::max(MaxLen, std::strlen(I.Key));
92 /// Display help for feature choices.
94 static void Help(ArrayRef<SubtargetFeatureKV> CPUTable,
95 ArrayRef<SubtargetFeatureKV> FeatTable) {
96 // Determine the length of the longest CPU and Feature entries.
97 unsigned MaxCPULen = getLongestEntryLength(CPUTable);
98 unsigned MaxFeatLen = getLongestEntryLength(FeatTable);
100 // Print the CPU table.
101 errs() << "Available CPUs for this target:\n\n";
102 for (auto &CPU : CPUTable)
103 errs() << format(" %-*s - %s.\n", MaxCPULen, CPU.Key, CPU.Desc);
106 // Print the Feature table.
107 errs() << "Available features for this target:\n\n";
108 for (auto &Feature : FeatTable)
109 errs() << format(" %-*s - %s.\n", MaxFeatLen, Feature.Key, Feature.Desc);
112 errs() << "Use +feature to enable a feature, or -feature to disable it.\n"
113 "For example, llc -mcpu=mycpu -mattr=+feature1,-feature2\n";
116 //===----------------------------------------------------------------------===//
117 // SubtargetFeatures Implementation
118 //===----------------------------------------------------------------------===//
120 SubtargetFeatures::SubtargetFeatures(StringRef Initial) {
121 // Break up string into separate features
122 Split(Features, Initial);
126 std::string SubtargetFeatures::getString() const {
127 return join(Features.begin(), Features.end(), ",");
130 /// SetImpliedBits - For each feature that is (transitively) implied by this
134 void SetImpliedBits(FeatureBitset &Bits, const SubtargetFeatureKV *FeatureEntry,
135 ArrayRef<SubtargetFeatureKV> FeatureTable) {
136 for (auto &FE : FeatureTable) {
137 if (FeatureEntry->Value == FE.Value) continue;
139 if ((FeatureEntry->Implies & FE.Value).any()) {
141 SetImpliedBits(Bits, &FE, FeatureTable);
146 /// ClearImpliedBits - For each feature that (transitively) implies this
147 /// feature, clear it.
150 void ClearImpliedBits(FeatureBitset &Bits,
151 const SubtargetFeatureKV *FeatureEntry,
152 ArrayRef<SubtargetFeatureKV> FeatureTable) {
153 for (auto &FE : FeatureTable) {
154 if (FeatureEntry->Value == FE.Value) continue;
156 if ((FE.Implies & FeatureEntry->Value).any()) {
158 ClearImpliedBits(Bits, &FE, FeatureTable);
163 /// ToggleFeature - Toggle a feature and update the feature bits.
165 SubtargetFeatures::ToggleFeature(FeatureBitset &Bits, StringRef Feature,
166 ArrayRef<SubtargetFeatureKV> FeatureTable) {
168 // Find feature in table.
169 const SubtargetFeatureKV *FeatureEntry =
170 Find(StripFlag(Feature), FeatureTable);
171 // If there is a match
173 if ((Bits & FeatureEntry->Value) == FeatureEntry->Value) {
174 Bits &= ~FeatureEntry->Value;
175 // For each feature that implies this, clear it.
176 ClearImpliedBits(Bits, FeatureEntry, FeatureTable);
178 Bits |= FeatureEntry->Value;
180 // For each feature that this implies, set it.
181 SetImpliedBits(Bits, FeatureEntry, FeatureTable);
184 errs() << "'" << Feature
185 << "' is not a recognized feature for this target"
186 << " (ignoring feature)\n";
190 void SubtargetFeatures::ApplyFeatureFlag(FeatureBitset &Bits, StringRef Feature,
191 ArrayRef<SubtargetFeatureKV> FeatureTable) {
193 assert(hasFlag(Feature));
195 // Find feature in table.
196 const SubtargetFeatureKV *FeatureEntry =
197 Find(StripFlag(Feature), FeatureTable);
198 // If there is a match
200 // Enable/disable feature in bits
201 if (isEnabled(Feature)) {
202 Bits |= FeatureEntry->Value;
204 // For each feature that this implies, set it.
205 SetImpliedBits(Bits, FeatureEntry, FeatureTable);
207 Bits &= ~FeatureEntry->Value;
209 // For each feature that implies this, clear it.
210 ClearImpliedBits(Bits, FeatureEntry, FeatureTable);
213 errs() << "'" << Feature
214 << "' is not a recognized feature for this target"
215 << " (ignoring feature)\n";
220 /// getFeatureBits - Get feature bits a CPU.
223 SubtargetFeatures::getFeatureBits(StringRef CPU,
224 ArrayRef<SubtargetFeatureKV> CPUTable,
225 ArrayRef<SubtargetFeatureKV> FeatureTable) {
227 if (CPUTable.empty() || FeatureTable.empty())
228 return FeatureBitset();
231 assert(std::is_sorted(std::begin(CPUTable), std::end(CPUTable)) &&
232 "CPU table is not sorted");
233 assert(std::is_sorted(std::begin(FeatureTable), std::end(FeatureTable)) &&
234 "CPU features table is not sorted");
239 // Check if help is needed
241 Help(CPUTable, FeatureTable);
243 // Find CPU entry if CPU name is specified.
244 else if (!CPU.empty()) {
245 const SubtargetFeatureKV *CPUEntry = Find(CPU, CPUTable);
247 // If there is a match
249 // Set base feature bits
250 Bits = CPUEntry->Value;
252 // Set the feature implied by this CPU feature, if any.
253 for (auto &FE : FeatureTable) {
254 if ((CPUEntry->Value & FE.Value).any())
255 SetImpliedBits(Bits, &FE, FeatureTable);
259 << "' is not a recognized processor for this target"
260 << " (ignoring processor)\n";
264 // Iterate through each feature
265 for (auto &Feature : Features) {
267 if (Feature == "+help")
268 Help(CPUTable, FeatureTable);
270 ApplyFeatureFlag(Bits, Feature, FeatureTable);
276 /// print - Print feature string.
278 void SubtargetFeatures::print(raw_ostream &OS) const {
279 for (auto &F : Features)
284 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
285 /// dump - Dump feature info.
287 void SubtargetFeatures::dump() const {
292 /// Adds the default features for the specified target triple.
294 /// FIXME: This is an inelegant way of specifying the features of a
295 /// subtarget. It would be better if we could encode this information
296 /// into the IR. See <rdar://5972456>.
298 void SubtargetFeatures::getDefaultSubtargetFeatures(const Triple& Triple) {
299 if (Triple.getVendor() == Triple::Apple) {
300 if (Triple.getArch() == Triple::ppc) {
302 AddFeature("altivec");
303 } else if (Triple.getArch() == Triple::ppc64) {
306 AddFeature("altivec");