1 //===- SubtargetFeatureInfo.cpp - Helpers for subtarget features ----------===//
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 #include "SubtargetFeatureInfo.h"
11 
12 #include "Types.h"
13 #include "llvm/Config/llvm-config.h"
14 #include "llvm/TableGen/Record.h"
15 
16 #include <map>
17 
18 using namespace llvm;
19 
20 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
21 LLVM_DUMP_METHOD void SubtargetFeatureInfo::dump() const {
22   errs() << getEnumName() << " " << Index << "\n" << *TheDef;
23 }
24 #endif
25 
26 std::vector<std::pair<Record *, SubtargetFeatureInfo>>
27 SubtargetFeatureInfo::getAll(const RecordKeeper &Records) {
28   std::vector<std::pair<Record *, SubtargetFeatureInfo>> SubtargetFeatures;
29   std::vector<Record *> AllPredicates =
30       Records.getAllDerivedDefinitions("Predicate");
31   for (Record *Pred : AllPredicates) {
32     // Ignore predicates that are not intended for the assembler.
33     //
34     // The "AssemblerMatcherPredicate" string should be promoted to an argument
35     // if we re-use the machinery for non-assembler purposes in future.
36     if (!Pred->getValueAsBit("AssemblerMatcherPredicate"))
37       continue;
38 
39     if (Pred->getName().empty())
40       PrintFatalError(Pred->getLoc(), "Predicate has no name!");
41 
42     SubtargetFeatures.emplace_back(
43         Pred, SubtargetFeatureInfo(Pred, SubtargetFeatures.size()));
44   }
45   return SubtargetFeatures;
46 }
47 
48 void SubtargetFeatureInfo::emitSubtargetFeatureFlagEnumeration(
49     SubtargetFeatureInfoMap &SubtargetFeatures, raw_ostream &OS) {
50   OS << "// Flags for subtarget features that participate in "
51      << "instruction matching.\n";
52   OS << "enum SubtargetFeatureFlag : "
53      << getMinimalTypeForEnumBitfield(SubtargetFeatures.size()) << " {\n";
54   for (const auto &SF : SubtargetFeatures) {
55     const SubtargetFeatureInfo &SFI = SF.second;
56     OS << "  " << SFI.getEnumName() << " = (1ULL << " << SFI.Index << "),\n";
57   }
58   OS << "  Feature_None = 0\n";
59   OS << "};\n\n";
60 }
61 
62 void SubtargetFeatureInfo::emitSubtargetFeatureBitEnumeration(
63     SubtargetFeatureInfoMap &SubtargetFeatures, raw_ostream &OS) {
64   OS << "// Bits for subtarget features that participate in "
65      << "instruction matching.\n";
66   OS << "enum SubtargetFeatureBits : "
67      << getMinimalTypeForRange(SubtargetFeatures.size()) << " {\n";
68   for (const auto &SF : SubtargetFeatures) {
69     const SubtargetFeatureInfo &SFI = SF.second;
70     OS << "  " << SFI.getEnumBitName() << " = " << SFI.Index << ",\n";
71   }
72   OS << "};\n\n";
73 }
74 
75 void SubtargetFeatureInfo::emitNameTable(
76     SubtargetFeatureInfoMap &SubtargetFeatures, raw_ostream &OS) {
77   // Need to sort the name table so that lookup by the log of the enum value
78   // gives the proper name. More specifically, for a feature of value 1<<n,
79   // SubtargetFeatureNames[n] should be the name of the feature.
80   uint64_t IndexUB = 0;
81   for (const auto &SF : SubtargetFeatures)
82     if (IndexUB <= SF.second.Index)
83       IndexUB = SF.second.Index+1;
84 
85   std::vector<std::string> Names;
86   if (IndexUB > 0)
87     Names.resize(IndexUB);
88   for (const auto &SF : SubtargetFeatures)
89     Names[SF.second.Index] = SF.second.getEnumName();
90 
91   OS << "static const char *SubtargetFeatureNames[] = {\n";
92   for (uint64_t I = 0; I < IndexUB; ++I)
93     OS << "  \"" << Names[I] << "\",\n";
94 
95   // A small number of targets have no predicates. Null terminate the array to
96   // avoid a zero-length array.
97   OS << "  nullptr\n"
98      << "};\n\n";
99 }
100 
101 void SubtargetFeatureInfo::emitComputeAvailableFeatures(
102     StringRef TargetName, StringRef ClassName, StringRef FuncName,
103     SubtargetFeatureInfoMap &SubtargetFeatures, raw_ostream &OS,
104     StringRef ExtraParams) {
105   OS << "PredicateBitset " << TargetName << ClassName << "::\n"
106      << FuncName << "(const " << TargetName << "Subtarget *Subtarget";
107   if (!ExtraParams.empty())
108     OS << ", " << ExtraParams;
109   OS << ") const {\n";
110   OS << "  PredicateBitset Features;\n";
111   for (const auto &SF : SubtargetFeatures) {
112     const SubtargetFeatureInfo &SFI = SF.second;
113 
114     OS << "  if (" << SFI.TheDef->getValueAsString("CondString") << ")\n";
115     OS << "    Features[" << SFI.getEnumBitName() << "] = 1;\n";
116   }
117   OS << "  return Features;\n";
118   OS << "}\n\n";
119 }
120 
121 void SubtargetFeatureInfo::emitComputeAssemblerAvailableFeatures(
122     StringRef TargetName, StringRef ClassName, StringRef FuncName,
123     SubtargetFeatureInfoMap &SubtargetFeatures, raw_ostream &OS) {
124   OS << "uint64_t " << TargetName << ClassName << "::\n"
125      << FuncName << "(const FeatureBitset& FB) const {\n";
126   OS << "  uint64_t Features = 0;\n";
127   for (const auto &SF : SubtargetFeatures) {
128     const SubtargetFeatureInfo &SFI = SF.second;
129 
130     OS << "  if (";
131     std::string CondStorage =
132         SFI.TheDef->getValueAsString("AssemblerCondString");
133     StringRef Conds = CondStorage;
134     std::pair<StringRef, StringRef> Comma = Conds.split(',');
135     bool First = true;
136     do {
137       if (!First)
138         OS << " && ";
139 
140       bool Neg = false;
141       StringRef Cond = Comma.first;
142       if (Cond[0] == '!') {
143         Neg = true;
144         Cond = Cond.substr(1);
145       }
146 
147       OS << "(";
148       if (Neg)
149         OS << "!";
150       OS << "FB[" << TargetName << "::" << Cond << "])";
151 
152       if (Comma.second.empty())
153         break;
154 
155       First = false;
156       Comma = Comma.second.split(',');
157     } while (true);
158 
159     OS << ")\n";
160     OS << "    Features |= " << SFI.getEnumName() << ";\n";
161   }
162   OS << "  return Features;\n";
163   OS << "}\n\n";
164 }
165