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//===----------------------- CodeRegionGenerator.cpp ------------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
/// \file
///
/// This file defines classes responsible for generating llvm-mca
/// CodeRegions from various types of input. llvm-mca only analyzes CodeRegions,
/// so the classes here provide the input-to-CodeRegions translation.
//
//===----------------------------------------------------------------------===//
#include "CodeRegionGenerator.h"
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/MC/MCParser/MCTargetAsmParser.h"
#include "llvm/MC/MCStreamer.h"
#include "llvm/MC/MCTargetOptions.h"
#include "llvm/Support/Error.h"
#include "llvm/Support/SMLoc.h"
#include <memory>
namespace llvm {
namespace mca {
// This virtual dtor serves as the anchor for the CodeRegionGenerator class.
CodeRegionGenerator::~CodeRegionGenerator() {}
// This class provides the callbacks that occur when parsing input assembly.
class MCStreamerWrapper final : public MCStreamer {
CodeRegions &Regions;
public:
MCStreamerWrapper(MCContext &Context, mca::CodeRegions &R)
: MCStreamer(Context), Regions(R) {}
// We only want to intercept the emission of new instructions.
void emitInstruction(const MCInst &Inst,
const MCSubtargetInfo & /* unused */) override {
Regions.addInstruction(Inst);
}
bool emitSymbolAttribute(MCSymbol *Symbol, MCSymbolAttr Attribute) override {
return true;
}
void emitCommonSymbol(MCSymbol *Symbol, uint64_t Size,
Align ByteAlignment) override {}
void emitZerofill(MCSection *Section, MCSymbol *Symbol = nullptr,
uint64_t Size = 0, Align ByteAlignment = Align(1),
SMLoc Loc = SMLoc()) override {}
void emitGPRel32Value(const MCExpr *Value) override {}
void beginCOFFSymbolDef(const MCSymbol *Symbol) override {}
void emitCOFFSymbolStorageClass(int StorageClass) override {}
void emitCOFFSymbolType(int Type) override {}
void endCOFFSymbolDef() override {}
ArrayRef<MCInst> GetInstructionSequence(unsigned Index) const {
return Regions.getInstructionSequence(Index);
}
};
Expected<const CodeRegions &> AsmCodeRegionGenerator::parseCodeRegions(
const std::unique_ptr<MCInstPrinter> &IP) {
MCTargetOptions Opts;
Opts.PreserveAsmComments = false;
CodeRegions &Regions = getRegions();
MCStreamerWrapper Str(Ctx, Regions);
// Need to initialize an MCTargetStreamer otherwise
// certain asm directives will cause a segfault.
// Using nulls() so that anything emitted by the MCTargetStreamer
// doesn't show up in the llvm-mca output.
raw_ostream &OSRef = nulls();
formatted_raw_ostream FOSRef(OSRef);
TheTarget.createAsmTargetStreamer(Str, FOSRef, IP.get(),
/*IsVerboseAsm=*/true);
// Create a MCAsmParser and setup the lexer to recognize llvm-mca ASM
// comments.
std::unique_ptr<MCAsmParser> Parser(
createMCAsmParser(Regions.getSourceMgr(), Ctx, Str, MAI));
MCAsmLexer &Lexer = Parser->getLexer();
MCACommentConsumer *CCP = getCommentConsumer();
Lexer.setCommentConsumer(CCP);
// Enable support for MASM literal numbers (example: 05h, 101b).
Lexer.setLexMasmIntegers(true);
std::unique_ptr<MCTargetAsmParser> TAP(
TheTarget.createMCAsmParser(STI, *Parser, MCII, Opts));
if (!TAP)
return make_error<StringError>(
"This target does not support assembly parsing.",
inconvertibleErrorCode());
Parser->setTargetParser(*TAP);
Parser->Run(false);
if (CCP->hadErr())
return make_error<StringError>("There was an error parsing comments.",
inconvertibleErrorCode());
// Set the assembler dialect from the input. llvm-mca will use this as the
// default dialect when printing reports.
AssemblerDialect = Parser->getAssemblerDialect();
return Regions;
}
void AnalysisRegionCommentConsumer::HandleComment(SMLoc Loc,
StringRef CommentText) {
// Skip empty comments.
StringRef Comment(CommentText);
if (Comment.empty())
return;
// Skip spaces and tabs.
unsigned Position = Comment.find_first_not_of(" \t");
if (Position >= Comment.size())
// We reached the end of the comment. Bail out.
return;
Comment = Comment.drop_front(Position);
if (Comment.consume_front("LLVM-MCA-END")) {
// Skip spaces and tabs.
Position = Comment.find_first_not_of(" \t");
if (Position < Comment.size())
Comment = Comment.drop_front(Position);
Regions.endRegion(Comment, Loc);
return;
}
// Try to parse the LLVM-MCA-BEGIN comment.
if (!Comment.consume_front("LLVM-MCA-BEGIN"))
return;
// Skip spaces and tabs.
Position = Comment.find_first_not_of(" \t");
if (Position < Comment.size())
Comment = Comment.drop_front(Position);
// Use the rest of the string as a descriptor for this code snippet.
Regions.beginRegion(Comment, Loc);
}
void InstrumentRegionCommentConsumer::HandleComment(SMLoc Loc,
StringRef CommentText) {
// Skip empty comments.
StringRef Comment(CommentText);
if (Comment.empty())
return;
// Skip spaces and tabs.
unsigned Position = Comment.find_first_not_of(" \t");
if (Position >= Comment.size())
// We reached the end of the comment. Bail out.
return;
Comment = Comment.drop_front(Position);
// Bail out if not an MCA style comment
if (!Comment.consume_front("LLVM-MCA-"))
return;
// Skip AnalysisRegion comments
if (Comment.consume_front("BEGIN") || Comment.consume_front("END"))
return;
if (IM.shouldIgnoreInstruments())
return;
auto [InstrumentKind, Data] = Comment.split(" ");
// An error if not of the form LLVM-MCA-TARGET-KIND
if (!IM.supportsInstrumentType(InstrumentKind)) {
if (InstrumentKind.empty())
SM.PrintMessage(
Loc, llvm::SourceMgr::DK_Error,
"No instrumentation kind was provided in LLVM-MCA comment");
else
SM.PrintMessage(Loc, llvm::SourceMgr::DK_Error,
"Unknown instrumentation type in LLVM-MCA comment: " +
InstrumentKind);
FoundError = true;
return;
}
SharedInstrument I = IM.createInstrument(InstrumentKind, Data);
if (!I) {
if (Data.empty())
SM.PrintMessage(Loc, llvm::SourceMgr::DK_Error,
"Failed to create " + InstrumentKind +
" instrument with no data");
else
SM.PrintMessage(Loc, llvm::SourceMgr::DK_Error,
"Failed to create " + InstrumentKind +
" instrument with data: " + Data);
FoundError = true;
return;
}
// End InstrumentType region if one is open
if (Regions.isRegionActive(InstrumentKind))
Regions.endRegion(InstrumentKind, Loc);
// Start new instrumentation region
Regions.beginRegion(InstrumentKind, Loc, I);
}
} // namespace mca
} // namespace llvm
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