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/MCAsmParser.h"
15 #include "llvm/MC/MCParser/MCTargetAsmParser.h"
16 #include "llvm/MC/MCRegisterInfo.h"
17 #include "llvm/MC/MCStreamer.h"
18 #include "llvm/Support/Format.h"
19 #include "llvm/Support/Path.h"
20 #include "llvm/Support/SourceMgr.h"
21 #include "llvm/Support/TargetRegistry.h"
22 #include <string>
23
24 namespace llvm {
25 namespace exegesis {
26 namespace {
27
28 // An MCStreamer that reads a BenchmarkCode definition from a file.
29 class BenchmarkCodeStreamer : public MCStreamer, public AsmCommentConsumer {
30 public:
BenchmarkCodeStreamer(MCContext * Context,const MCRegisterInfo * TheRegInfo,BenchmarkCode * Result)31 explicit BenchmarkCodeStreamer(MCContext *Context,
32 const MCRegisterInfo *TheRegInfo,
33 BenchmarkCode *Result)
34 : MCStreamer(*Context), RegInfo(TheRegInfo), Result(Result) {}
35
36 // Implementation of the MCStreamer interface. We only care about
37 // instructions.
emitInstruction(const MCInst & Instruction,const MCSubtargetInfo & STI)38 void emitInstruction(const MCInst &Instruction,
39 const MCSubtargetInfo &STI) override {
40 Result->Key.Instructions.push_back(Instruction);
41 }
42
43 // Implementation of the AsmCommentConsumer.
HandleComment(SMLoc Loc,StringRef CommentText)44 void HandleComment(SMLoc Loc, StringRef CommentText) override {
45 CommentText = CommentText.trim();
46 if (!CommentText.consume_front("LLVM-EXEGESIS-"))
47 return;
48 if (CommentText.consume_front("DEFREG")) {
49 // LLVM-EXEGESIS-DEFREF <reg> <hex_value>
50 RegisterValue RegVal;
51 SmallVector<StringRef, 2> Parts;
52 CommentText.split(Parts, ' ', /*unlimited splits*/ -1,
53 /*do not keep empty strings*/ false);
54 if (Parts.size() != 2) {
55 errs() << "invalid comment 'LLVM-EXEGESIS-DEFREG " << CommentText
56 << "', expected two parameters <REG> <HEX_VALUE>\n";
57 ++InvalidComments;
58 return;
59 }
60 if (!(RegVal.Register = findRegisterByName(Parts[0].trim()))) {
61 errs() << "unknown register '" << Parts[0]
62 << "' in 'LLVM-EXEGESIS-DEFREG " << CommentText << "'\n";
63 ++InvalidComments;
64 return;
65 }
66 const StringRef HexValue = Parts[1].trim();
67 RegVal.Value = APInt(
68 /* each hex digit is 4 bits */ HexValue.size() * 4, HexValue, 16);
69 Result->Key.RegisterInitialValues.push_back(std::move(RegVal));
70 return;
71 }
72 if (CommentText.consume_front("LIVEIN")) {
73 // LLVM-EXEGESIS-LIVEIN <reg>
74 const auto RegName = CommentText.ltrim();
75 if (unsigned Reg = findRegisterByName(RegName))
76 Result->LiveIns.push_back(Reg);
77 else {
78 errs() << "unknown register '" << RegName
79 << "' in 'LLVM-EXEGESIS-LIVEIN " << CommentText << "'\n";
80 ++InvalidComments;
81 }
82 return;
83 }
84 }
85
numInvalidComments() const86 unsigned numInvalidComments() const { return InvalidComments; }
87
88 private:
89 // We only care about instructions, we don't implement this part of the API.
emitCommonSymbol(MCSymbol * Symbol,uint64_t Size,unsigned ByteAlignment)90 void emitCommonSymbol(MCSymbol *Symbol, uint64_t Size,
91 unsigned ByteAlignment) override {}
emitSymbolAttribute(MCSymbol * Symbol,MCSymbolAttr Attribute)92 bool emitSymbolAttribute(MCSymbol *Symbol, MCSymbolAttr Attribute) override {
93 return false;
94 }
emitValueToAlignment(unsigned ByteAlignment,int64_t Value,unsigned ValueSize,unsigned MaxBytesToEmit)95 void emitValueToAlignment(unsigned ByteAlignment, int64_t Value,
96 unsigned ValueSize,
97 unsigned MaxBytesToEmit) override {}
emitZerofill(MCSection * Section,MCSymbol * Symbol,uint64_t Size,unsigned ByteAlignment,SMLoc Loc)98 void emitZerofill(MCSection *Section, MCSymbol *Symbol, uint64_t Size,
99 unsigned ByteAlignment, SMLoc Loc) override {}
100
findRegisterByName(const StringRef RegName) const101 unsigned findRegisterByName(const StringRef RegName) const {
102 // FIXME: Can we do better than this ?
103 for (unsigned I = 0, E = RegInfo->getNumRegs(); I < E; ++I) {
104 if (RegName == RegInfo->getName(I))
105 return I;
106 }
107 errs() << "'" << RegName
108 << "' is not a valid register name for the target\n";
109 return 0;
110 }
111
112 const MCRegisterInfo *const RegInfo;
113 BenchmarkCode *const Result;
114 unsigned InvalidComments = 0;
115 };
116
117 } // namespace
118
119 // Reads code snippets from file `Filename`.
readSnippets(const LLVMState & State,StringRef Filename)120 Expected<std::vector<BenchmarkCode>> readSnippets(const LLVMState &State,
121 StringRef Filename) {
122 ErrorOr<std::unique_ptr<MemoryBuffer>> BufferPtr =
123 MemoryBuffer::getFileOrSTDIN(Filename);
124 if (std::error_code EC = BufferPtr.getError()) {
125 return make_error<Failure>("cannot read snippet: " + Filename + ": " +
126 EC.message());
127 }
128 SourceMgr SM;
129 SM.AddNewSourceBuffer(std::move(BufferPtr.get()), SMLoc());
130
131 BenchmarkCode Result;
132
133 MCObjectFileInfo ObjectFileInfo;
134 const TargetMachine &TM = State.getTargetMachine();
135 MCContext Context(TM.getMCAsmInfo(), TM.getMCRegisterInfo(), &ObjectFileInfo);
136 ObjectFileInfo.InitMCObjectFileInfo(TM.getTargetTriple(), /*PIC*/ false,
137 Context);
138 BenchmarkCodeStreamer Streamer(&Context, TM.getMCRegisterInfo(), &Result);
139
140 std::string Error;
141 raw_string_ostream ErrorStream(Error);
142 formatted_raw_ostream InstPrinterOStream(ErrorStream);
143 const std::unique_ptr<MCInstPrinter> InstPrinter(
144 TM.getTarget().createMCInstPrinter(
145 TM.getTargetTriple(), TM.getMCAsmInfo()->getAssemblerDialect(),
146 *TM.getMCAsmInfo(), *TM.getMCInstrInfo(), *TM.getMCRegisterInfo()));
147 // The following call will take care of calling Streamer.setTargetStreamer.
148 TM.getTarget().createAsmTargetStreamer(Streamer, InstPrinterOStream,
149 InstPrinter.get(),
150 TM.Options.MCOptions.AsmVerbose);
151 if (!Streamer.getTargetStreamer())
152 return make_error<Failure>("cannot create target asm streamer");
153
154 const std::unique_ptr<MCAsmParser> AsmParser(
155 createMCAsmParser(SM, Context, Streamer, *TM.getMCAsmInfo()));
156 if (!AsmParser)
157 return make_error<Failure>("cannot create asm parser");
158 AsmParser->getLexer().setCommentConsumer(&Streamer);
159
160 const std::unique_ptr<MCTargetAsmParser> TargetAsmParser(
161 TM.getTarget().createMCAsmParser(*TM.getMCSubtargetInfo(), *AsmParser,
162 *TM.getMCInstrInfo(),
163 MCTargetOptions()));
164
165 if (!TargetAsmParser)
166 return make_error<Failure>("cannot create target asm parser");
167 AsmParser->setTargetParser(*TargetAsmParser);
168
169 if (AsmParser->Run(false))
170 return make_error<Failure>("cannot parse asm file");
171 if (Streamer.numInvalidComments())
172 return make_error<Failure>(Twine("found ")
173 .concat(Twine(Streamer.numInvalidComments()))
174 .concat(" invalid LLVM-EXEGESIS comments"));
175 return std::vector<BenchmarkCode>{std::move(Result)};
176 }
177
178 } // namespace exegesis
179 } // namespace llvm
180