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/Support/Debug.h"
16 #include "llvm/Support/Format.h"
17 #include "llvm/Support/raw_ostream.h"
24 //===----------------------------------------------------------------------===//
25 // Static Helper Functions
26 //===----------------------------------------------------------------------===//
28 /// hasFlag - Determine if a feature has a flag; '+' or '-'
30 static inline bool hasFlag(const StringRef Feature) {
31 assert(!Feature.empty() && "Empty string");
32 // Get first character
34 // Check if first character is '+' or '-' flag
35 return Ch == '+' || Ch =='-';
38 /// StripFlag - Return string stripped of flag.
40 static inline std::string StripFlag(const StringRef Feature) {
41 return hasFlag(Feature) ? Feature.substr(1) : Feature;
44 /// isEnabled - Return true if enable flag; '+'.
46 static inline bool isEnabled(const StringRef Feature) {
47 assert(!Feature.empty() && "Empty string");
48 // Get first character
50 // Check if first character is '+' for enabled
54 /// PrependFlag - Return a string with a prepended flag; '+' or '-'.
56 static inline std::string PrependFlag(const StringRef Feature,
58 assert(!Feature.empty() && "Empty string");
61 std::string Prefix = IsEnabled ? "+" : "-";
66 /// Split - Splits a string of comma separated items in to a vector of strings.
68 static void Split(std::vector<std::string> &V, const StringRef S) {
72 // Start at beginning of string.
75 // Find the next comma
76 size_t Comma = S.find(',', Pos);
77 // If no comma found then the rest of the string is used
78 if (Comma == std::string::npos) {
79 // Add string to vector
80 V.push_back(S.substr(Pos));
83 // Otherwise add substring to vector
84 V.push_back(S.substr(Pos, Comma - Pos));
85 // Advance to next item
90 /// Join a vector of strings to a string with a comma separating each element.
92 static std::string Join(const std::vector<std::string> &V) {
93 // Start with empty string.
95 // If the vector is not empty
97 // Start with the first feature
99 // For each successive feature
100 for (size_t i = 1; i < V.size(); i++) {
107 // Return the features string
112 void SubtargetFeatures::AddFeature(const StringRef String) {
113 // Don't add empty features
114 if (!String.empty()) {
115 // Convert to lowercase, prepend flag and add to vector
116 Features.push_back(PrependFlag(String.lower(), true));
120 /// Find KV in array using binary search.
121 static const SubtargetFeatureKV *Find(StringRef S, const SubtargetFeatureKV *A,
123 // Determine the end of the array
124 const SubtargetFeatureKV *Hi = A + L;
125 // Binary search the array
126 const SubtargetFeatureKV *F = std::lower_bound(A, Hi, S);
127 // If not found then return NULL
128 if (F == Hi || StringRef(F->Key) != S) return nullptr;
129 // Return the found array item
133 /// getLongestEntryLength - Return the length of the longest entry in the table.
135 static size_t getLongestEntryLength(const SubtargetFeatureKV *Table,
138 for (size_t i = 0; i < Size; i++)
139 MaxLen = std::max(MaxLen, std::strlen(Table[i].Key));
143 /// Display help for feature choices.
145 static void Help(const SubtargetFeatureKV *CPUTable, size_t CPUTableSize,
146 const SubtargetFeatureKV *FeatTable, size_t FeatTableSize) {
147 // Determine the length of the longest CPU and Feature entries.
148 unsigned MaxCPULen = getLongestEntryLength(CPUTable, CPUTableSize);
149 unsigned MaxFeatLen = getLongestEntryLength(FeatTable, FeatTableSize);
151 // Print the CPU table.
152 errs() << "Available CPUs for this target:\n\n";
153 for (size_t i = 0; i != CPUTableSize; i++)
154 errs() << format(" %-*s - %s.\n",
155 MaxCPULen, CPUTable[i].Key, CPUTable[i].Desc);
158 // Print the Feature table.
159 errs() << "Available features for this target:\n\n";
160 for (size_t i = 0; i != FeatTableSize; i++)
161 errs() << format(" %-*s - %s.\n",
162 MaxFeatLen, FeatTable[i].Key, FeatTable[i].Desc);
165 errs() << "Use +feature to enable a feature, or -feature to disable it.\n"
166 "For example, llc -mcpu=mycpu -mattr=+feature1,-feature2\n";
170 //===----------------------------------------------------------------------===//
171 // SubtargetFeatures Implementation
172 //===----------------------------------------------------------------------===//
174 SubtargetFeatures::SubtargetFeatures(const StringRef Initial) {
175 // Break up string into separate features
176 Split(Features, Initial);
180 std::string SubtargetFeatures::getString() const {
181 return Join(Features);
184 /// SetImpliedBits - For each feature that is (transitively) implied by this
188 void SetImpliedBits(uint64_t &Bits, const SubtargetFeatureKV *FeatureEntry,
189 const SubtargetFeatureKV *FeatureTable,
190 size_t FeatureTableSize) {
191 for (size_t i = 0; i < FeatureTableSize; ++i) {
192 const SubtargetFeatureKV &FE = FeatureTable[i];
194 if (FeatureEntry->Value == FE.Value) continue;
196 if (FeatureEntry->Implies & FE.Value) {
198 SetImpliedBits(Bits, &FE, FeatureTable, FeatureTableSize);
203 /// ClearImpliedBits - For each feature that (transitively) implies this
204 /// feature, clear it.
207 void ClearImpliedBits(uint64_t &Bits, const SubtargetFeatureKV *FeatureEntry,
208 const SubtargetFeatureKV *FeatureTable,
209 size_t FeatureTableSize) {
210 for (size_t i = 0; i < FeatureTableSize; ++i) {
211 const SubtargetFeatureKV &FE = FeatureTable[i];
213 if (FeatureEntry->Value == FE.Value) continue;
215 if (FE.Implies & FeatureEntry->Value) {
217 ClearImpliedBits(Bits, &FE, FeatureTable, FeatureTableSize);
222 /// ToggleFeature - Toggle a feature and returns the newly updated feature
225 SubtargetFeatures::ToggleFeature(uint64_t Bits, const StringRef Feature,
226 const SubtargetFeatureKV *FeatureTable,
227 size_t FeatureTableSize) {
228 // Find feature in table.
229 const SubtargetFeatureKV *FeatureEntry =
230 Find(StripFlag(Feature), FeatureTable, FeatureTableSize);
231 // If there is a match
233 if ((Bits & FeatureEntry->Value) == FeatureEntry->Value) {
234 Bits &= ~FeatureEntry->Value;
236 // For each feature that implies this, clear it.
237 ClearImpliedBits(Bits, FeatureEntry, FeatureTable, FeatureTableSize);
239 Bits |= FeatureEntry->Value;
241 // For each feature that this implies, set it.
242 SetImpliedBits(Bits, FeatureEntry, FeatureTable, FeatureTableSize);
245 errs() << "'" << Feature
246 << "' is not a recognized feature for this target"
247 << " (ignoring feature)\n";
254 /// getFeatureBits - Get feature bits a CPU.
256 uint64_t SubtargetFeatures::getFeatureBits(const StringRef CPU,
257 const SubtargetFeatureKV *CPUTable,
259 const SubtargetFeatureKV *FeatureTable,
260 size_t FeatureTableSize) {
261 if (!FeatureTableSize || !CPUTableSize)
265 for (size_t i = 1; i < CPUTableSize; i++) {
266 assert(strcmp(CPUTable[i - 1].Key, CPUTable[i].Key) < 0 &&
267 "CPU table is not sorted");
269 for (size_t i = 1; i < FeatureTableSize; i++) {
270 assert(strcmp(FeatureTable[i - 1].Key, FeatureTable[i].Key) < 0 &&
271 "CPU features table is not sorted");
274 uint64_t Bits = 0; // Resulting bits
276 // Check if help is needed
278 Help(CPUTable, CPUTableSize, FeatureTable, FeatureTableSize);
280 // Find CPU entry if CPU name is specified.
282 const SubtargetFeatureKV *CPUEntry = Find(CPU, CPUTable, CPUTableSize);
283 // If there is a match
285 // Set base feature bits
286 Bits = CPUEntry->Value;
288 // Set the feature implied by this CPU feature, if any.
289 for (size_t i = 0; i < FeatureTableSize; ++i) {
290 const SubtargetFeatureKV &FE = FeatureTable[i];
291 if (CPUEntry->Value & FE.Value)
292 SetImpliedBits(Bits, &FE, FeatureTable, FeatureTableSize);
296 << "' is not a recognized processor for this target"
297 << " (ignoring processor)\n";
301 // Iterate through each feature
302 for (size_t i = 0, E = Features.size(); i < E; i++) {
303 const StringRef Feature = Features[i];
306 if (Feature == "+help")
307 Help(CPUTable, CPUTableSize, FeatureTable, FeatureTableSize);
309 // Find feature in table.
310 const SubtargetFeatureKV *FeatureEntry =
311 Find(StripFlag(Feature), FeatureTable, FeatureTableSize);
312 // If there is a match
314 // Enable/disable feature in bits
315 if (isEnabled(Feature)) {
316 Bits |= FeatureEntry->Value;
318 // For each feature that this implies, set it.
319 SetImpliedBits(Bits, FeatureEntry, FeatureTable, FeatureTableSize);
321 Bits &= ~FeatureEntry->Value;
323 // For each feature that implies this, clear it.
324 ClearImpliedBits(Bits, FeatureEntry, FeatureTable, FeatureTableSize);
327 errs() << "'" << Feature
328 << "' is not a recognized feature for this target"
329 << " (ignoring feature)\n";
336 /// print - Print feature string.
338 void SubtargetFeatures::print(raw_ostream &OS) const {
339 for (size_t i = 0, e = Features.size(); i != e; ++i)
340 OS << Features[i] << " ";
344 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
345 /// dump - Dump feature info.
347 void SubtargetFeatures::dump() const {
352 /// Adds the default features for the specified target triple.
354 /// FIXME: This is an inelegant way of specifying the features of a
355 /// subtarget. It would be better if we could encode this information
356 /// into the IR. See <rdar://5972456>.
358 void SubtargetFeatures::getDefaultSubtargetFeatures(const Triple& Triple) {
359 if (Triple.getVendor() == Triple::Apple) {
360 if (Triple.getArch() == Triple::ppc) {
362 AddFeature("altivec");
363 } else if (Triple.getArch() == Triple::ppc64) {
366 AddFeature("altivec");