1 //===- SubtargetFeature.cpp - CPU characteristics Implementation ----------===//
3 // The LLVM Compiler Infrastructure
5 // This file was developed by Jim Laskey and is distributed under the
6 // University of Illinois Open Source License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file implements the SubtargetFeature interface.
12 //===----------------------------------------------------------------------===//
14 #include "llvm/Target/SubtargetFeature.h"
15 #include "llvm/ADT/StringExtras.h"
22 //===----------------------------------------------------------------------===//
23 // Static Helper Functions
24 //===----------------------------------------------------------------------===//
26 /// hasFlag - Determine if a feature has a flag; '+' or '-'
28 static inline bool hasFlag(const std::string &Feature) {
29 assert(!Feature.empty() && "Empty string");
30 // Get first character
32 // Check if first character is '+' or '-' flag
33 return Ch == '+' || Ch =='-';
36 /// StripFlag - Return string stripped of flag.
38 static inline std::string StripFlag(const std::string &Feature) {
39 return hasFlag(Feature) ? Feature.substr(1) : Feature;
42 /// isEnabled - Return true if enable flag; '+'.
44 static inline bool isEnabled(const std::string &Feature) {
45 assert(!Feature.empty() && "Empty string");
46 // Get first character
48 // Check if first character is '+' for enabled
52 /// PrependFlag - Return a string with a prepended flag; '+' or '-'.
54 static inline std::string PrependFlag(const std::string &Feature,
56 assert(!Feature.empty() && "Empty string");
57 if (hasFlag(Feature)) return Feature;
58 return std::string(IsEnabled ? "+" : "-") + Feature;
61 /// Split - Splits a string of comma separated items in to a vector of strings.
63 static void Split(std::vector<std::string> &V, const std::string &S) {
64 // Start at beginning of string.
67 // Find the next comma
68 size_t Comma = S.find(',', Pos);
69 // If no comma found then the the rest of the string is used
70 if (Comma == std::string::npos) {
71 // Add string to vector
72 V.push_back(S.substr(Pos));
75 // Otherwise add substring to vector
76 V.push_back(S.substr(Pos, Comma - Pos));
77 // Advance to next item
82 /// Join a vector of strings to a string with a comma separating each element.
84 static std::string Join(const std::vector<std::string> &V) {
85 // Start with empty string.
87 // If the vector is not empty
89 // Start with the CPU feature
91 // For each successive feature
92 for (size_t i = 1; i < V.size(); i++) {
99 // Return the features string
104 void SubtargetFeatures::AddFeature(const std::string &String,
106 // Don't add empty features
107 if (!String.empty()) {
108 // Convert to lowercase, prepend flag and add to vector
109 Features.push_back(PrependFlag(LowercaseString(String), IsEnabled));
113 /// Find item in array using binary search.
114 static const SubtargetFeatureKV *Find(const std::string &S,
115 const SubtargetFeatureKV *A, size_t L) {
116 // Determine the end of the array
117 const SubtargetFeatureKV *Hi = A + L;
118 // Binary search the array
119 const SubtargetFeatureKV *F = std::lower_bound(A, Hi, S);
120 // If not found then return NULL
121 if (F == Hi || std::string(F->Key) != S) return NULL;
122 // Return the found array item
126 /// Display help for feature choices.
128 static void Help(bool isFeature, const SubtargetFeatureKV *Table,
130 // Determine the length of the longest key.
132 for (size_t i = 0; i < TableSize; i++)
133 MaxLen = std::max(MaxLen, std::strlen(Table[i].Key));
135 std::cerr << "Available " << (isFeature ? "features" : "CPUs")
136 << " for this target:\n\n";
138 for (size_t i = 0; i < TableSize; i++) {
139 // Compute required padding
140 size_t Pad = MaxLen - std::strlen(Table[i].Key);
141 std::cerr << Table[i].Key << std::string(Pad, ' ') << " - "
142 << Table[i].Desc << ".\n";
148 << "Use +feature to enable a feature, or -feature to disable it.\n"
149 << "For example, llc -mcpu=mycpu -mattr=+feature1,-feature2\n";
154 //===----------------------------------------------------------------------===//
155 // SubtargetFeatures Implementation
156 //===----------------------------------------------------------------------===//
158 SubtargetFeatures::SubtargetFeatures(const std::string &Initial) {
159 // Break up string into separate features
160 Split(Features, Initial);
164 std::string SubtargetFeatures::getString() const {
165 return Join(Features);
167 void SubtargetFeatures::setString(const std::string &Initial) {
168 // Throw out old features
170 // Break up string into separate features
171 Split(Features, LowercaseString(Initial));
174 /// setCPU - Set the CPU string. Replaces previous setting. Setting to ""
176 void SubtargetFeatures::setCPU(const std::string &String) {
177 Features[0] = LowercaseString(String);
182 /// Parse feature string for quick usage.
184 uint32_t SubtargetFeatures::Parse(const std::string &String,
185 const std::string &DefaultCPU,
186 const SubtargetFeatureKV *CPUTable,
188 const SubtargetFeatureKV *FeatureTable,
189 size_t FeatureTableSize) {
190 assert(CPUTable && "missing CPU table");
191 assert(FeatureTable && "missing features table");
193 for (size_t i = 1; i < CPUTableSize; i++) {
194 assert(strcmp(CPUTable[i - 1].Key, CPUTable[i].Key) < 0 &&
195 "CPU table is not sorted");
197 for (size_t i = 1; i < FeatureTableSize; i++) {
198 assert(strcmp(FeatureTable[i - 1].Key, FeatureTable[i].Key) < 0 &&
199 "CPU features table is not sorted");
202 std::vector<std::string> Features; // Subtarget features as a vector
203 uint32_t Bits = 0; // Resulting bits
205 Split(Features, String);
206 // Check if default is needed
207 if (Features[0].empty()) Features[0] = DefaultCPU;
209 if (Features[0] == "help") Help(false, CPUTable, CPUTableSize);
211 const SubtargetFeatureKV *CPUEntry =
212 Find(Features[0], CPUTable, CPUTableSize);
213 // If there is a match
215 // Set base feature bits
216 Bits = CPUEntry->Value;
218 std::cerr << "'" << Features[0]
219 << "' is not a recognized processor for this target"
220 << " (ignoring processor)"
223 // Iterate through each feature
224 for (size_t i = 1; i < Features.size(); i++) {
226 const std::string &Feature = Features[i];
228 if (Feature == "+help") Help(true, FeatureTable, FeatureTableSize);
229 // Find feature in table.
230 const SubtargetFeatureKV *FeatureEntry =
231 Find(StripFlag(Feature), FeatureTable, FeatureTableSize);
232 // If there is a match
234 // Enable/disable feature in bits
235 if (isEnabled(Feature)) Bits |= FeatureEntry->Value;
236 else Bits &= ~FeatureEntry->Value;
238 std::cerr << "'" << Feature
239 << "' is not a recognized feature for this target"
240 << " (ignoring feature)"
247 /// Print feature string.
248 void SubtargetFeatures::print(std::ostream &OS) const {
249 for (size_t i = 0; i < Features.size(); i++) {
250 OS << Features[i] << " ";
255 /// Dump feature info.
256 void SubtargetFeatures::dump() const {