llvm/tools/llvm-mca/CodeRegionGenerator.cpp

   1 //===----------------------- CodeRegionGenerator.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 /// \file
   9 ///
  10 /// This file defines classes responsible for generating llvm-mca
  11 /// CodeRegions from various types of input. llvm-mca only analyzes CodeRegions,
  12 /// so the classes here provide the input-to-CodeRegions translation.
  13 //
  14 //===----------------------------------------------------------------------===//
  15
  16 #include "CodeRegionGenerator.h"
  17 #include "llvm/ADT/ArrayRef.h"
  18 #include "llvm/ADT/StringRef.h"
  19 #include "llvm/MC/MCParser/MCTargetAsmParser.h"
  20 #include "llvm/MC/MCTargetOptions.h"
  21 #include "llvm/Support/Error.h"
  22 #include "llvm/Support/SMLoc.h"
  23 #include <memory>
  24
  25 namespace llvm {
  26 namespace mca {
  27
  28 // This virtual dtor serves as the anchor for the CodeRegionGenerator class.
  29 CodeRegionGenerator::~CodeRegionGenerator() {}
  30
  31 Expected<const CodeRegions &> AsmCodeRegionGenerator::parseCodeRegions(
  32     const std::unique_ptr<MCInstPrinter> &IP) {
  33   MCTargetOptions Opts;
  34   Opts.PreserveAsmComments = false;
  35   CodeRegions &Regions = getRegions();
  36   MCStreamerWrapper *Str = getMCStreamer();
  37
  38   // Need to initialize an MCTargetStreamer otherwise
  39   // certain asm directives will cause a segfault.
  40   // Using nulls() so that anything emitted by the MCTargetStreamer
  41   // doesn't show up in the llvm-mca output.
  42   raw_ostream &OSRef = nulls();
  43   formatted_raw_ostream FOSRef(OSRef);
  44   TheTarget.createAsmTargetStreamer(*Str, FOSRef, IP.get(),
  45                                     /*IsVerboseAsm=*/true);
  46
  47   // Create a MCAsmParser and setup the lexer to recognize llvm-mca ASM
  48   // comments.
  49   std::unique_ptr<MCAsmParser> Parser(
  50       createMCAsmParser(Regions.getSourceMgr(), Ctx, *Str, MAI));
  51   MCAsmLexer &Lexer = Parser->getLexer();
  52   MCACommentConsumer *CCP = getCommentConsumer();
  53   Lexer.setCommentConsumer(CCP);
  54   // Enable support for MASM literal numbers (example: 05h, 101b).
  55   Lexer.setLexMasmIntegers(true);
  56
  57   std::unique_ptr<MCTargetAsmParser> TAP(
  58       TheTarget.createMCAsmParser(STI, *Parser, MCII, Opts));
  59   if (!TAP)
  60     return make_error<StringError>(
  61         "This target does not support assembly parsing.",
  62         inconvertibleErrorCode());
  63   Parser->setTargetParser(*TAP);
  64   Parser->Run(false);
  65
  66   if (CCP->hadErr())
  67     return make_error<StringError>("There was an error parsing comments.",
  68                                    inconvertibleErrorCode());
  69
  70   // Set the assembler dialect from the input. llvm-mca will use this as the
  71   // default dialect when printing reports.
  72   AssemblerDialect = Parser->getAssemblerDialect();
  73   return Regions;
  74 }
  75
  76 void AnalysisRegionCommentConsumer::HandleComment(SMLoc Loc,
  77                                                   StringRef CommentText) {
  78   // Skip empty comments.
  79   StringRef Comment(CommentText);
  80   if (Comment.empty())
  81     return;
  82
  83   // Skip spaces and tabs.
  84   unsigned Position = Comment.find_first_not_of(" \t");
  85   if (Position >= Comment.size())
  86     // We reached the end of the comment. Bail out.
  87     return;
  88
  89   Comment = Comment.drop_front(Position);
  90   if (Comment.consume_front("LLVM-MCA-END")) {
  91     // Skip spaces and tabs.
  92     Position = Comment.find_first_not_of(" \t");
  93     if (Position < Comment.size())
  94       Comment = Comment.drop_front(Position);
  95     Regions.endRegion(Comment, Loc);
  96     return;
  97   }
  98
  99   // Try to parse the LLVM-MCA-BEGIN comment.
 100   if (!Comment.consume_front("LLVM-MCA-BEGIN"))
 101     return;
 102
 103   // Skip spaces and tabs.
 104   Position = Comment.find_first_not_of(" \t");
 105   if (Position < Comment.size())
 106     Comment = Comment.drop_front(Position);
 107   // Use the rest of the string as a descriptor for this code snippet.
 108   Regions.beginRegion(Comment, Loc);
 109 }
 110
 111 void InstrumentRegionCommentConsumer::HandleComment(SMLoc Loc,
 112                                                     StringRef CommentText) {
 113   // Skip empty comments.
 114   StringRef Comment(CommentText);
 115   if (Comment.empty())
 116     return;
 117
 118   // Skip spaces and tabs.
 119   unsigned Position = Comment.find_first_not_of(" \t");
 120   if (Position >= Comment.size())
 121     // We reached the end of the comment. Bail out.
 122     return;
 123   Comment = Comment.drop_front(Position);
 124
 125   // Bail out if not an MCA style comment
 126   if (!Comment.consume_front("LLVM-MCA-"))
 127     return;
 128
 129   // Skip AnalysisRegion comments
 130   if (Comment.consume_front("BEGIN") || Comment.consume_front("END"))
 131     return;
 132
 133   if (IM.shouldIgnoreInstruments())
 134     return;
 135
 136   auto [InstrumentKind, Data] = Comment.split(" ");
 137
 138   // An error if not of the form LLVM-MCA-TARGET-KIND
 139   if (!IM.supportsInstrumentType(InstrumentKind)) {
 140     if (InstrumentKind.empty())
 141       SM.PrintMessage(
 142           Loc, llvm::SourceMgr::DK_Error,
 143           "No instrumentation kind was provided in LLVM-MCA comment");
 144     else
 145       SM.PrintMessage(Loc, llvm::SourceMgr::DK_Error,
 146                       "Unknown instrumentation type in LLVM-MCA comment: " +
 147                           InstrumentKind);
 148     FoundError = true;
 149     return;
 150   }
 151
 152   UniqueInstrument I = IM.createInstrument(InstrumentKind, Data);
 153   if (!I) {
 154     if (Data.empty())
 155       SM.PrintMessage(Loc, llvm::SourceMgr::DK_Error,
 156                       "Failed to create " + InstrumentKind +
 157                           " instrument with no data");
 158     else
 159       SM.PrintMessage(Loc, llvm::SourceMgr::DK_Error,
 160                       "Failed to create " + InstrumentKind +
 161                           " instrument with data: " + Data);
 162     FoundError = true;
 163     return;
 164   }
 165
 166   // End InstrumentType region if one is open
 167   if (Regions.isRegionActive(InstrumentKind))
 168     Regions.endRegion(InstrumentKind, Loc);
 169   // Start new instrumentation region
 170   Regions.beginRegion(InstrumentKind, Loc, std::move(I));
 171 }
 172
 173 } // namespace mca
 174 } // namespace llvm