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/TableGen/Record.h"
14 
15 #include <map>
16 
17 using namespace llvm;
18 
19 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
20 LLVM_DUMP_METHOD void SubtargetFeatureInfo::dump() const {
21   errs() << getEnumName() << " " << Index << "\n" << *TheDef;
22 }
23 #endif
24 
25 std::vector<std::pair<Record *, SubtargetFeatureInfo>>
26 SubtargetFeatureInfo::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     SubtargetFeatures.emplace_back(
42         Pred, SubtargetFeatureInfo(Pred, SubtargetFeatures.size()));
43   }
44   return SubtargetFeatures;
45 }
46 
47 void SubtargetFeatureInfo::emitSubtargetFeatureFlagEnumeration(
48     std::map<Record *, SubtargetFeatureInfo, LessRecordByID> &SubtargetFeatures,
49     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::emitNameTable(
63     std::map<Record *, SubtargetFeatureInfo, LessRecordByID> &SubtargetFeatures,
64     raw_ostream &OS) {
65   OS << "static const char *SubtargetFeatureNames[] = {\n";
66   for (const auto &SF : SubtargetFeatures) {
67     const SubtargetFeatureInfo &SFI = SF.second;
68     OS << "  \"" << SFI.getEnumName() << "\",\n";
69   }
70   // A small number of targets have no predicates. Null terminate the array to
71   // avoid a zero-length array.
72   OS << "  nullptr\n"
73      << "};\n\n";
74 }
75 
76 void SubtargetFeatureInfo::emitComputeAvailableFeatures(
77     StringRef TargetName, StringRef ClassName, StringRef FuncName,
78     std::map<Record *, SubtargetFeatureInfo, LessRecordByID> &SubtargetFeatures,
79     raw_ostream &OS) {
80   OS << "uint64_t " << TargetName << ClassName << "::\n"
81      << FuncName << "(const FeatureBitset& FB) const {\n";
82   OS << "  uint64_t Features = 0;\n";
83   for (const auto &SF : SubtargetFeatures) {
84     const SubtargetFeatureInfo &SFI = SF.second;
85 
86     OS << "  if (";
87     std::string CondStorage =
88         SFI.TheDef->getValueAsString("AssemblerCondString");
89     StringRef Conds = CondStorage;
90     std::pair<StringRef, StringRef> Comma = Conds.split(',');
91     bool First = true;
92     do {
93       if (!First)
94         OS << " && ";
95 
96       bool Neg = false;
97       StringRef Cond = Comma.first;
98       if (Cond[0] == '!') {
99         Neg = true;
100         Cond = Cond.substr(1);
101       }
102 
103       OS << "(";
104       if (Neg)
105         OS << "!";
106       OS << "FB[" << TargetName << "::" << Cond << "])";
107 
108       if (Comma.second.empty())
109         break;
110 
111       First = false;
112       Comma = Comma.second.split(',');
113     } while (true);
114 
115     OS << ")\n";
116     OS << "    Features |= " << SFI.getEnumName() << ";\n";
117   }
118   OS << "  return Features;\n";
119   OS << "}\n\n";
120 }
121