1 //==- X86MnemonicTables.cpp - Generate mnemonic extraction tables. -*- C++ -*-//
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 // This tablegen backend is responsible for emitting tables that group
10 // instructions by their mnemonic name wrt AsmWriter Variant (e.g. isADD, etc).
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "CodeGenInstruction.h"
15 #include "CodeGenTarget.h"
16 #include "X86RecognizableInstr.h"
17 #include "llvm/TableGen/Record.h"
18 #include "llvm/TableGen/TableGenBackend.h"
19 
20 using namespace llvm;
21 
22 namespace {
23 
24 class X86MnemonicTablesEmitter {
25   CodeGenTarget Target;
26 
27 public:
28   X86MnemonicTablesEmitter(RecordKeeper &R) : Target(R) {}
29 
30   // Output X86 mnemonic tables.
31   void run(raw_ostream &OS);
32 };
33 
34 void X86MnemonicTablesEmitter::run(raw_ostream &OS) {
35   emitSourceFileHeader("X86 Mnemonic tables", OS);
36   OS << "namespace llvm {\nnamespace X86 {\n\n";
37   Record *AsmWriter = Target.getAsmWriter();
38   unsigned Variant = AsmWriter->getValueAsInt("Variant");
39 
40   // Hold all instructions grouped by mnemonic
41   StringMap<SmallVector<const CodeGenInstruction *, 0>> MnemonicToCGInstrMap;
42 
43   ArrayRef<const CodeGenInstruction *> NumberedInstructions =
44       Target.getInstructionsByEnumValue();
45   for (const CodeGenInstruction *I : NumberedInstructions) {
46     const Record *Def = I->TheDef;
47     // Filter non-X86 instructions.
48     if (!Def->isSubClassOf("X86Inst"))
49       continue;
50     X86Disassembler::RecognizableInstrBase RI(*I);
51     if (!RI.shouldBeEmitted())
52       continue;
53     if ( // Non-parsable instruction defs contain prefix as part of AsmString
54         Def->getValueAsString("AsmVariantName") == "NonParsable" ||
55         // Skip prefix byte
56         RI.Form == X86Local::PrefixByte)
57       continue;
58     std::string Mnemonic = X86Disassembler::getMnemonic(I, Variant);
59     MnemonicToCGInstrMap[Mnemonic].push_back(I);
60   }
61 
62   OS << "#ifdef GET_X86_MNEMONIC_TABLES_H\n";
63   OS << "#undef GET_X86_MNEMONIC_TABLES_H\n\n";
64   for (StringRef Mnemonic : MnemonicToCGInstrMap.keys())
65     OS << "bool is" << Mnemonic << "(unsigned Opcode);\n";
66   OS << "#endif // GET_X86_MNEMONIC_TABLES_H\n\n";
67 
68   OS << "#ifdef GET_X86_MNEMONIC_TABLES_CPP\n";
69   OS << "#undef GET_X86_MNEMONIC_TABLES_CPP\n\n";
70   for (StringRef Mnemonic : MnemonicToCGInstrMap.keys()) {
71     OS << "bool is" << Mnemonic << "(unsigned Opcode) {\n";
72     auto Mnemonics = MnemonicToCGInstrMap[Mnemonic];
73     if (Mnemonics.size() == 1) {
74       const CodeGenInstruction *CGI = *Mnemonics.begin();
75       OS << "\treturn Opcode == " << CGI->TheDef->getName() << ";\n}\n\n";
76     } else {
77       OS << "\tswitch (Opcode) {\n";
78       for (const CodeGenInstruction *CGI : Mnemonics) {
79         OS << "\tcase " << CGI->TheDef->getName() << ":\n";
80       }
81       OS << "\t\treturn true;\n\t}\n\treturn false;\n}\n\n";
82     }
83   }
84   OS << "#endif // GET_X86_MNEMONIC_TABLES_CPP\n\n";
85   OS << "} // end namespace X86\n} // end namespace llvm";
86 }
87 
88 } // namespace
89 
90 static TableGen::Emitter::OptClass<X86MnemonicTablesEmitter>
91     X("gen-x86-mnemonic-tables", "Generate X86 mnemonic tables");
92