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    std::string CondStorage =
123        SFI.TheDef->getValueAsString("AssemblerCondString");
124    StringRef Conds = CondStorage;
125    std::pair<StringRef, StringRef> Comma = Conds.split(',');
126    bool First = true;
127    do {
128      if (!First)
129        OS << " && ";
130
131      bool Neg = false;
132      StringRef Cond = Comma.first;
133      if (Cond[0] == '!') {
134        Neg = true;
135        Cond = Cond.substr(1);
136      }
137
138      OS << "(";
139      if (Neg)
140        OS << "!";
141      OS << "FB[" << TargetName << "::" << Cond << "])";
142
143      if (Comma.second.empty())
144        break;
145
146      First = false;
147      Comma = Comma.second.split(',');
148    } while (true);
149
150    OS << ")\n";
151    OS << "    Features.set(" << SFI.getEnumBitName() << ");\n";
152  }
153  OS << "  return Features;\n";
154  OS << "}\n\n";
155}
156