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