xref: /openbsd-src/gnu/llvm/llvm/tools/llvm-exegesis/lib/SnippetFile.cpp (revision d415bd752c734aee168c4ee86ff32e8cc249eb16)
1 //===-- SnippetFile.cpp -----------------------------------------*- 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 #include "SnippetFile.h"
10 #include "Error.h"
11 #include "llvm/MC/MCContext.h"
12 #include "llvm/MC/MCInstPrinter.h"
13 #include "llvm/MC/MCObjectFileInfo.h"
14 #include "llvm/MC/MCParser/MCAsmLexer.h"
15 #include "llvm/MC/MCParser/MCAsmParser.h"
16 #include "llvm/MC/MCParser/MCTargetAsmParser.h"
17 #include "llvm/MC/MCRegisterInfo.h"
18 #include "llvm/MC/MCStreamer.h"
19 #include "llvm/MC/TargetRegistry.h"
20 #include "llvm/Support/Format.h"
21 #include "llvm/Support/Path.h"
22 #include "llvm/Support/SourceMgr.h"
23 #include <string>
24 
25 namespace llvm {
26 namespace exegesis {
27 namespace {
28 
29 // An MCStreamer that reads a BenchmarkCode definition from a file.
30 class BenchmarkCodeStreamer : public MCStreamer, public AsmCommentConsumer {
31 public:
BenchmarkCodeStreamer(MCContext * Context,const DenseMap<StringRef,unsigned> & RegNameToRegNo,BenchmarkCode * Result)32   explicit BenchmarkCodeStreamer(
33       MCContext *Context, const DenseMap<StringRef, unsigned> &RegNameToRegNo,
34       BenchmarkCode *Result)
35       : MCStreamer(*Context), RegNameToRegNo(RegNameToRegNo), Result(Result) {}
36 
37   // Implementation of the MCStreamer interface. We only care about
38   // instructions.
emitInstruction(const MCInst & Instruction,const MCSubtargetInfo & STI)39   void emitInstruction(const MCInst &Instruction,
40                        const MCSubtargetInfo &STI) override {
41     Result->Key.Instructions.push_back(Instruction);
42   }
43 
44   // Implementation of the AsmCommentConsumer.
HandleComment(SMLoc Loc,StringRef CommentText)45   void HandleComment(SMLoc Loc, StringRef CommentText) override {
46     CommentText = CommentText.trim();
47     if (!CommentText.consume_front("LLVM-EXEGESIS-"))
48       return;
49     if (CommentText.consume_front("DEFREG")) {
50       // LLVM-EXEGESIS-DEFREF <reg> <hex_value>
51       RegisterValue RegVal;
52       SmallVector<StringRef, 2> Parts;
53       CommentText.split(Parts, ' ', /*unlimited splits*/ -1,
54                         /*do not keep empty strings*/ false);
55       if (Parts.size() != 2) {
56         errs() << "invalid comment 'LLVM-EXEGESIS-DEFREG " << CommentText
57                << "', expected two parameters <REG> <HEX_VALUE>\n";
58         ++InvalidComments;
59         return;
60       }
61       if (!(RegVal.Register = findRegisterByName(Parts[0].trim()))) {
62         errs() << "unknown register '" << Parts[0]
63                << "' in 'LLVM-EXEGESIS-DEFREG " << CommentText << "'\n";
64         ++InvalidComments;
65         return;
66       }
67       const StringRef HexValue = Parts[1].trim();
68       RegVal.Value = APInt(
69           /* each hex digit is 4 bits */ HexValue.size() * 4, HexValue, 16);
70       Result->Key.RegisterInitialValues.push_back(std::move(RegVal));
71       return;
72     }
73     if (CommentText.consume_front("LIVEIN")) {
74       // LLVM-EXEGESIS-LIVEIN <reg>
75       const auto RegName = CommentText.ltrim();
76       if (unsigned Reg = findRegisterByName(RegName))
77         Result->LiveIns.push_back(Reg);
78       else {
79         errs() << "unknown register '" << RegName
80                << "' in 'LLVM-EXEGESIS-LIVEIN " << CommentText << "'\n";
81         ++InvalidComments;
82       }
83       return;
84     }
85   }
86 
numInvalidComments() const87   unsigned numInvalidComments() const { return InvalidComments; }
88 
89 private:
90   // We only care about instructions, we don't implement this part of the API.
emitCommonSymbol(MCSymbol * Symbol,uint64_t Size,Align ByteAlignment)91   void emitCommonSymbol(MCSymbol *Symbol, uint64_t Size,
92                         Align ByteAlignment) override {}
emitSymbolAttribute(MCSymbol * Symbol,MCSymbolAttr Attribute)93   bool emitSymbolAttribute(MCSymbol *Symbol, MCSymbolAttr Attribute) override {
94     return false;
95   }
emitValueToAlignment(Align Alignment,int64_t Value,unsigned ValueSize,unsigned MaxBytesToEmit)96   void emitValueToAlignment(Align Alignment, int64_t Value, unsigned ValueSize,
97                             unsigned MaxBytesToEmit) override {}
emitZerofill(MCSection * Section,MCSymbol * Symbol,uint64_t Size,Align ByteAlignment,SMLoc Loc)98   void emitZerofill(MCSection *Section, MCSymbol *Symbol, uint64_t Size,
99                     Align ByteAlignment, SMLoc Loc) override {}
100 
findRegisterByName(const StringRef RegName) const101   unsigned findRegisterByName(const StringRef RegName) const {
102     auto Iter = RegNameToRegNo.find(RegName);
103     if (Iter != RegNameToRegNo.end())
104       return Iter->second;
105     errs() << "'" << RegName
106            << "' is not a valid register name for the target\n";
107     return 0;
108   }
109 
110   const DenseMap<StringRef, unsigned> &RegNameToRegNo;
111   BenchmarkCode *const Result;
112   unsigned InvalidComments = 0;
113 };
114 
115 } // namespace
116 
117 // Reads code snippets from file `Filename`.
readSnippets(const LLVMState & State,StringRef Filename)118 Expected<std::vector<BenchmarkCode>> readSnippets(const LLVMState &State,
119                                                   StringRef Filename) {
120   ErrorOr<std::unique_ptr<MemoryBuffer>> BufferPtr =
121       MemoryBuffer::getFileOrSTDIN(Filename);
122   if (std::error_code EC = BufferPtr.getError()) {
123     return make_error<Failure>("cannot read snippet: " + Filename + ": " +
124                                EC.message());
125   }
126   SourceMgr SM;
127   SM.AddNewSourceBuffer(std::move(BufferPtr.get()), SMLoc());
128 
129   BenchmarkCode Result;
130 
131   const TargetMachine &TM = State.getTargetMachine();
132   MCContext Context(TM.getTargetTriple(), TM.getMCAsmInfo(),
133                     TM.getMCRegisterInfo(), TM.getMCSubtargetInfo());
134   std::unique_ptr<MCObjectFileInfo> ObjectFileInfo(
135       TM.getTarget().createMCObjectFileInfo(Context, /*PIC=*/false));
136   Context.setObjectFileInfo(ObjectFileInfo.get());
137   Context.initInlineSourceManager();
138   BenchmarkCodeStreamer Streamer(&Context, State.getRegNameToRegNoMapping(),
139                                  &Result);
140 
141   std::string Error;
142   raw_string_ostream ErrorStream(Error);
143   formatted_raw_ostream InstPrinterOStream(ErrorStream);
144   const std::unique_ptr<MCInstPrinter> InstPrinter(
145       TM.getTarget().createMCInstPrinter(
146           TM.getTargetTriple(), TM.getMCAsmInfo()->getAssemblerDialect(),
147           *TM.getMCAsmInfo(), *TM.getMCInstrInfo(), *TM.getMCRegisterInfo()));
148   // The following call will take care of calling Streamer.setTargetStreamer.
149   TM.getTarget().createAsmTargetStreamer(Streamer, InstPrinterOStream,
150                                          InstPrinter.get(),
151                                          TM.Options.MCOptions.AsmVerbose);
152   if (!Streamer.getTargetStreamer())
153     return make_error<Failure>("cannot create target asm streamer");
154 
155   const std::unique_ptr<MCAsmParser> AsmParser(
156       createMCAsmParser(SM, Context, Streamer, *TM.getMCAsmInfo()));
157   if (!AsmParser)
158     return make_error<Failure>("cannot create asm parser");
159   AsmParser->getLexer().setCommentConsumer(&Streamer);
160 
161   const std::unique_ptr<MCTargetAsmParser> TargetAsmParser(
162       TM.getTarget().createMCAsmParser(*TM.getMCSubtargetInfo(), *AsmParser,
163                                        *TM.getMCInstrInfo(),
164                                        MCTargetOptions()));
165 
166   if (!TargetAsmParser)
167     return make_error<Failure>("cannot create target asm parser");
168   AsmParser->setTargetParser(*TargetAsmParser);
169 
170   if (AsmParser->Run(false))
171     return make_error<Failure>("cannot parse asm file");
172   if (Streamer.numInvalidComments())
173     return make_error<Failure>(Twine("found ")
174                                    .concat(Twine(Streamer.numInvalidComments()))
175                                    .concat(" invalid LLVM-EXEGESIS comments"));
176   return std::vector<BenchmarkCode>{std::move(Result)};
177 }
178 
179 } // namespace exegesis
180 } // namespace llvm
181