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