1 //===-------------------------- TargetRecip.cpp ---------------------------===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This class is used to customize machine-specific reciprocal estimate code
11 // generation in a target-independent way.
12 // If a target does not support operations in this specification, then code
13 // generation will default to using supported operations.
14 //
15 //===----------------------------------------------------------------------===//
16
17 #include "llvm/Target/TargetRecip.h"
18 #include "llvm/ADT/STLExtras.h"
19 #include "llvm/ADT/StringRef.h"
20 #include "llvm/Support/ErrorHandling.h"
21
22 using namespace llvm;
23
24 // These are the names of the individual reciprocal operations. These are
25 // the key strings for queries and command-line inputs.
26 // In addition, the command-line interface recognizes the global parameters
27 // "all", "none", and "default".
28 static const char *const RecipOps[] = {
29 "divd",
30 "divf",
31 "vec-divd",
32 "vec-divf",
33 "sqrtd",
34 "sqrtf",
35 "vec-sqrtd",
36 "vec-sqrtf",
37 };
38
39 // The uninitialized state is needed for the enabled settings and refinement
40 // steps because custom settings may arrive via the command-line before target
41 // defaults are set.
TargetRecip()42 TargetRecip::TargetRecip() {
43 unsigned NumStrings = llvm::array_lengthof(RecipOps);
44 for (unsigned i = 0; i < NumStrings; ++i)
45 RecipMap.insert(std::make_pair(RecipOps[i], RecipParams()));
46 }
47
parseRefinementStep(StringRef In,size_t & Position,uint8_t & Value)48 static bool parseRefinementStep(StringRef In, size_t &Position,
49 uint8_t &Value) {
50 const char RefStepToken = ':';
51 Position = In.find(RefStepToken);
52 if (Position == StringRef::npos)
53 return false;
54
55 StringRef RefStepString = In.substr(Position + 1);
56 // Allow exactly one numeric character for the additional refinement
57 // step parameter.
58 if (RefStepString.size() == 1) {
59 char RefStepChar = RefStepString[0];
60 if (RefStepChar >= '0' && RefStepChar <= '9') {
61 Value = RefStepChar - '0';
62 return true;
63 }
64 }
65 report_fatal_error("Invalid refinement step for -recip.");
66 }
67
parseGlobalParams(const std::string & Arg)68 bool TargetRecip::parseGlobalParams(const std::string &Arg) {
69 StringRef ArgSub = Arg;
70
71 // Look for an optional setting of the number of refinement steps needed
72 // for this type of reciprocal operation.
73 size_t RefPos;
74 uint8_t RefSteps;
75 StringRef RefStepString;
76 if (parseRefinementStep(ArgSub, RefPos, RefSteps)) {
77 // Split the string for further processing.
78 RefStepString = ArgSub.substr(RefPos + 1);
79 ArgSub = ArgSub.substr(0, RefPos);
80 }
81 bool Enable;
82 bool UseDefaults;
83 if (ArgSub == "all") {
84 UseDefaults = false;
85 Enable = true;
86 } else if (ArgSub == "none") {
87 UseDefaults = false;
88 Enable = false;
89 } else if (ArgSub == "default") {
90 UseDefaults = true;
91 } else {
92 // Any other string is invalid or an individual setting.
93 return false;
94 }
95
96 // All enable values will be initialized to target defaults if 'default' was
97 // specified.
98 if (!UseDefaults)
99 for (auto &KV : RecipMap)
100 KV.second.Enabled = Enable;
101
102 // Custom refinement count was specified with all, none, or default.
103 if (!RefStepString.empty())
104 for (auto &KV : RecipMap)
105 KV.second.RefinementSteps = RefSteps;
106
107 return true;
108 }
109
parseIndividualParams(const std::vector<std::string> & Args)110 void TargetRecip::parseIndividualParams(const std::vector<std::string> &Args) {
111 static const char DisabledPrefix = '!';
112 unsigned NumArgs = Args.size();
113
114 for (unsigned i = 0; i != NumArgs; ++i) {
115 StringRef Val = Args[i];
116
117 bool IsDisabled = Val[0] == DisabledPrefix;
118 // Ignore the disablement token for string matching.
119 if (IsDisabled)
120 Val = Val.substr(1);
121
122 size_t RefPos;
123 uint8_t RefSteps;
124 StringRef RefStepString;
125 if (parseRefinementStep(Val, RefPos, RefSteps)) {
126 // Split the string for further processing.
127 RefStepString = Val.substr(RefPos + 1);
128 Val = Val.substr(0, RefPos);
129 }
130
131 RecipIter Iter = RecipMap.find(Val);
132 if (Iter == RecipMap.end()) {
133 // Try again specifying float suffix.
134 Iter = RecipMap.find(Val.str() + 'f');
135 if (Iter == RecipMap.end()) {
136 Iter = RecipMap.find(Val.str() + 'd');
137 assert(Iter == RecipMap.end() && "Float entry missing from map");
138 report_fatal_error("Invalid option for -recip.");
139 }
140
141 // The option was specified without a float or double suffix.
142 if (RecipMap[Val.str() + 'd'].Enabled != Uninitialized) {
143 // Make sure that the double entry was not already specified.
144 // The float entry will be checked below.
145 report_fatal_error("Duplicate option for -recip.");
146 }
147 }
148
149 if (Iter->second.Enabled != Uninitialized)
150 report_fatal_error("Duplicate option for -recip.");
151
152 // Mark the matched option as found. Do not allow duplicate specifiers.
153 Iter->second.Enabled = !IsDisabled;
154 if (!RefStepString.empty())
155 Iter->second.RefinementSteps = RefSteps;
156
157 // If the precision was not specified, the double entry is also initialized.
158 if (Val.back() != 'f' && Val.back() != 'd') {
159 RecipParams &Params = RecipMap[Val.str() + 'd'];
160 Params.Enabled = !IsDisabled;
161 if (!RefStepString.empty())
162 Params.RefinementSteps = RefSteps;
163 }
164 }
165 }
166
TargetRecip(const std::vector<std::string> & Args)167 TargetRecip::TargetRecip(const std::vector<std::string> &Args) :
168 TargetRecip() {
169 unsigned NumArgs = Args.size();
170
171 // Check if "all", "default", or "none" was specified.
172 if (NumArgs == 1 && parseGlobalParams(Args[0]))
173 return;
174
175 parseIndividualParams(Args);
176 }
177
isEnabled(StringRef Key) const178 bool TargetRecip::isEnabled(StringRef Key) const {
179 ConstRecipIter Iter = RecipMap.find(Key);
180 assert(Iter != RecipMap.end() && "Unknown name for reciprocal map");
181 assert(Iter->second.Enabled != Uninitialized &&
182 "Enablement setting was not initialized");
183 return Iter->second.Enabled;
184 }
185
getRefinementSteps(StringRef Key) const186 unsigned TargetRecip::getRefinementSteps(StringRef Key) const {
187 ConstRecipIter Iter = RecipMap.find(Key);
188 assert(Iter != RecipMap.end() && "Unknown name for reciprocal map");
189 assert(Iter->second.RefinementSteps != Uninitialized &&
190 "Refinement step setting was not initialized");
191 return Iter->second.RefinementSteps;
192 }
193
194 /// Custom settings (previously initialized values) override target defaults.
setDefaults(StringRef Key,bool Enable,unsigned RefSteps)195 void TargetRecip::setDefaults(StringRef Key, bool Enable,
196 unsigned RefSteps) {
197 if (Key == "all") {
198 for (auto &KV : RecipMap) {
199 RecipParams &RP = KV.second;
200 if (RP.Enabled == Uninitialized)
201 RP.Enabled = Enable;
202 if (RP.RefinementSteps == Uninitialized)
203 RP.RefinementSteps = RefSteps;
204 }
205 } else {
206 RecipParams &RP = RecipMap[Key];
207 if (RP.Enabled == Uninitialized)
208 RP.Enabled = Enable;
209 if (RP.RefinementSteps == Uninitialized)
210 RP.RefinementSteps = RefSteps;
211 }
212 }
213
operator ==(const TargetRecip & Other) const214 bool TargetRecip::operator==(const TargetRecip &Other) const {
215 for (const auto &KV : RecipMap) {
216 StringRef Op = KV.first;
217 const RecipParams &RP = KV.second;
218 const RecipParams &OtherRP = Other.RecipMap.find(Op)->second;
219 if (RP.RefinementSteps != OtherRP.RefinementSteps)
220 return false;
221 if (RP.Enabled != OtherRP.Enabled)
222 return false;
223 }
224 return true;
225 }
226