1 //===- SubtargetFeatureInfo.cpp - Helpers for subtarget features ----------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8
9 #include "SubtargetFeatureInfo.h"
10 #include "Types.h"
11 #include "llvm/Config/llvm-config.h"
12 #include "llvm/TableGen/Error.h"
13 #include "llvm/TableGen/Record.h"
14 #include <map>
15
16 using namespace llvm;
17
18 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
dump() const19 LLVM_DUMP_METHOD void SubtargetFeatureInfo::dump() const {
20 errs() << getEnumName() << " " << Index << "\n" << *TheDef;
21 }
22 #endif
23
24 std::vector<std::pair<Record *, SubtargetFeatureInfo>>
getAll(const RecordKeeper & Records)25 SubtargetFeatureInfo::getAll(const RecordKeeper &Records) {
26 std::vector<std::pair<Record *, SubtargetFeatureInfo>> SubtargetFeatures;
27 std::vector<Record *> AllPredicates =
28 Records.getAllDerivedDefinitions("Predicate");
29 for (Record *Pred : AllPredicates) {
30 // Ignore predicates that are not intended for the assembler.
31 //
32 // The "AssemblerMatcherPredicate" string should be promoted to an argument
33 // if we re-use the machinery for non-assembler purposes in future.
34 if (!Pred->getValueAsBit("AssemblerMatcherPredicate"))
35 continue;
36
37 if (Pred->getName().empty())
38 PrintFatalError(Pred->getLoc(), "Predicate has no name!");
39
40 // Ignore always true predicates.
41 if (Pred->getValueAsString("CondString").empty())
42 continue;
43
44 SubtargetFeatures.emplace_back(
45 Pred, SubtargetFeatureInfo(Pred, SubtargetFeatures.size()));
46 }
47 return SubtargetFeatures;
48 }
49
emitSubtargetFeatureBitEnumeration(SubtargetFeatureInfoMap & SubtargetFeatures,raw_ostream & OS)50 void SubtargetFeatureInfo::emitSubtargetFeatureBitEnumeration(
51 SubtargetFeatureInfoMap &SubtargetFeatures, raw_ostream &OS) {
52 OS << "// Bits for subtarget features that participate in "
53 << "instruction matching.\n";
54 OS << "enum SubtargetFeatureBits : "
55 << getMinimalTypeForRange(SubtargetFeatures.size()) << " {\n";
56 for (const auto &SF : SubtargetFeatures) {
57 const SubtargetFeatureInfo &SFI = SF.second;
58 OS << " " << SFI.getEnumBitName() << " = " << SFI.Index << ",\n";
59 }
60 OS << "};\n\n";
61 }
62
emitNameTable(SubtargetFeatureInfoMap & SubtargetFeatures,raw_ostream & OS)63 void SubtargetFeatureInfo::emitNameTable(
64 SubtargetFeatureInfoMap &SubtargetFeatures, raw_ostream &OS) {
65 // Need to sort the name table so that lookup by the log of the enum value
66 // gives the proper name. More specifically, for a feature of value 1<<n,
67 // SubtargetFeatureNames[n] should be the name of the feature.
68 uint64_t IndexUB = 0;
69 for (const auto &SF : SubtargetFeatures)
70 if (IndexUB <= SF.second.Index)
71 IndexUB = SF.second.Index+1;
72
73 std::vector<std::string> Names;
74 if (IndexUB > 0)
75 Names.resize(IndexUB);
76 for (const auto &SF : SubtargetFeatures)
77 Names[SF.second.Index] = SF.second.getEnumName();
78
79 OS << "static const char *SubtargetFeatureNames[] = {\n";
80 for (uint64_t I = 0; I < IndexUB; ++I)
81 OS << " \"" << Names[I] << "\",\n";
82
83 // A small number of targets have no predicates. Null terminate the array to
84 // avoid a zero-length array.
85 OS << " nullptr\n"
86 << "};\n\n";
87 }
88
emitComputeAvailableFeatures(StringRef TargetName,StringRef ClassName,StringRef FuncName,SubtargetFeatureInfoMap & SubtargetFeatures,raw_ostream & OS,StringRef ExtraParams)89 void SubtargetFeatureInfo::emitComputeAvailableFeatures(
90 StringRef TargetName, StringRef ClassName, StringRef FuncName,
91 SubtargetFeatureInfoMap &SubtargetFeatures, raw_ostream &OS,
92 StringRef ExtraParams) {
93 OS << "PredicateBitset " << TargetName << ClassName << "::\n"
94 << FuncName << "(const " << TargetName << "Subtarget *Subtarget";
95 if (!ExtraParams.empty())
96 OS << ", " << ExtraParams;
97 OS << ") const {\n";
98 OS << " PredicateBitset Features;\n";
99 for (const auto &SF : SubtargetFeatures) {
100 const SubtargetFeatureInfo &SFI = SF.second;
101 StringRef CondStr = SFI.TheDef->getValueAsString("CondString");
102 assert(!CondStr.empty() && "true predicate should have been filtered");
103
104 OS << " if (" << CondStr << ")\n";
105 OS << " Features.set(" << SFI.getEnumBitName() << ");\n";
106 }
107 OS << " return Features;\n";
108 OS << "}\n\n";
109 }
110
111 // If ParenIfBinOp is true, print a surrounding () if Val uses && or ||.
emitFeaturesAux(StringRef TargetName,const Init & Val,bool ParenIfBinOp,raw_ostream & OS)112 static bool emitFeaturesAux(StringRef TargetName, const Init &Val,
113 bool ParenIfBinOp, raw_ostream &OS) {
114 if (auto *D = dyn_cast<DefInit>(&Val)) {
115 if (!D->getDef()->isSubClassOf("SubtargetFeature"))
116 return true;
117 OS << "FB[" << TargetName << "::" << D->getAsString() << "]";
118 return false;
119 }
120 if (auto *D = dyn_cast<DagInit>(&Val)) {
121 std::string Op = D->getOperator()->getAsString();
122 if (Op == "not" && D->getNumArgs() == 1) {
123 OS << '!';
124 return emitFeaturesAux(TargetName, *D->getArg(0), true, OS);
125 }
126 if ((Op == "any_of" || Op == "all_of") && D->getNumArgs() > 0) {
127 bool Paren = D->getNumArgs() > 1 && std::exchange(ParenIfBinOp, true);
128 if (Paren)
129 OS << '(';
130 ListSeparator LS(Op == "any_of" ? " || " : " && ");
131 for (auto *Arg : D->getArgs()) {
132 OS << LS;
133 if (emitFeaturesAux(TargetName, *Arg, ParenIfBinOp, OS))
134 return true;
135 }
136 if (Paren)
137 OS << ')';
138 return false;
139 }
140 }
141 return true;
142 }
143
emitComputeAssemblerAvailableFeatures(StringRef TargetName,StringRef ClassName,StringRef FuncName,SubtargetFeatureInfoMap & SubtargetFeatures,raw_ostream & OS)144 void SubtargetFeatureInfo::emitComputeAssemblerAvailableFeatures(
145 StringRef TargetName, StringRef ClassName, StringRef FuncName,
146 SubtargetFeatureInfoMap &SubtargetFeatures, raw_ostream &OS) {
147 OS << "FeatureBitset ";
148 if (!ClassName.empty())
149 OS << TargetName << ClassName << "::\n";
150 OS << FuncName << "(const FeatureBitset &FB) ";
151 if (!ClassName.empty())
152 OS << "const ";
153 OS << "{\n";
154 OS << " FeatureBitset Features;\n";
155 for (const auto &SF : SubtargetFeatures) {
156 const SubtargetFeatureInfo &SFI = SF.second;
157
158 OS << " if (";
159 emitFeaturesAux(TargetName, *SFI.TheDef->getValueAsDag("AssemblerCondDag"),
160 /*ParenIfBinOp=*/false, OS);
161 OS << ")\n";
162 OS << " Features.set(" << SFI.getEnumBitName() << ");\n";
163 }
164 OS << " return Features;\n";
165 OS << "}\n\n";
166 }
167