xref: /freebsd-src/contrib/llvm-project/llvm/lib/MC/MCParser/COFFMasmParser.cpp (revision 5ffd83dbcc34f10e07f6d3e968ae6365869615f4)

//===- COFFMasmParser.cpp - COFF MASM Assembly Parser ---------------------===//
//
// 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
//
//===----------------------------------------------------------------------===//

#include "llvm/ADT/StringRef.h"
#include "llvm/ADT/StringSwitch.h"
#include "llvm/ADT/Triple.h"
#include "llvm/ADT/Twine.h"
#include "llvm/BinaryFormat/COFF.h"
#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCDirectives.h"
#include "llvm/MC/MCObjectFileInfo.h"
#include "llvm/MC/MCParser/MCAsmLexer.h"
#include "llvm/MC/MCParser/MCAsmParserExtension.h"
#include "llvm/MC/MCParser/MCAsmParserUtils.h"
#include "llvm/MC/MCParser/MCTargetAsmParser.h"
#include "llvm/MC/MCRegisterInfo.h"
#include "llvm/MC/MCSectionCOFF.h"
#include "llvm/MC/MCStreamer.h"
#include "llvm/MC/SectionKind.h"
#include "llvm/Support/SMLoc.h"
#include <cassert>
#include <cstdint>
#include <limits>
#include <utility>

using namespace llvm;

namespace {

class COFFMasmParser : public MCAsmParserExtension {
  template <bool (COFFMasmParser::*HandlerMethod)(StringRef, SMLoc)>
  void addDirectiveHandler(StringRef Directive) {
    MCAsmParser::ExtensionDirectiveHandler Handler =
        std::make_pair(this, HandleDirective<COFFMasmParser, HandlerMethod>);
    getParser().addDirectiveHandler(Directive, Handler);
  }

  bool ParseSectionSwitch(StringRef Section, unsigned Characteristics,
                          SectionKind Kind);

  bool ParseSectionSwitch(StringRef Section, unsigned Characteristics,
                          SectionKind Kind, StringRef COMDATSymName,
                          COFF::COMDATType Type);

  bool ParseDirectiveProc(StringRef, SMLoc);
  bool ParseDirectiveEndProc(StringRef, SMLoc);
  bool ParseDirectiveSegment(StringRef, SMLoc);
  bool ParseDirectiveSegmentEnd(StringRef, SMLoc);
  bool ParseDirectiveIncludelib(StringRef, SMLoc);

  bool IgnoreDirective(StringRef, SMLoc) {
    while (!getLexer().is(AsmToken::EndOfStatement)) {
      Lex();
    }
    return false;
  }

  void Initialize(MCAsmParser &Parser) override {
    // Call the base implementation.
    MCAsmParserExtension::Initialize(Parser);

    // x64 directives
    // .allocstack
    // .endprolog
    // .pushframe
    // .pushreg
    // .savereg
    // .savexmm128
    // .setframe

    // Code label directives
    // label
    // org

    // Conditional control flow directives
    // .break
    // .continue
    // .else
    // .elseif
    // .endif
    // .endw
    // .if
    // .repeat
    // .until
    // .untilcxz
    // .while

    // Data allocation directives
    // align
    // byte/sbyte
    // dword/sdword
    // even
    // fword
    // qword
    // real4
    // real8
    // real10
    // tbyte
    // word/sword

    // Listing control directives
    addDirectiveHandler<&COFFMasmParser::IgnoreDirective>(".cref");
    addDirectiveHandler<&COFFMasmParser::IgnoreDirective>(".list");
    addDirectiveHandler<&COFFMasmParser::IgnoreDirective>(".listall");
    addDirectiveHandler<&COFFMasmParser::IgnoreDirective>(".listif");
    addDirectiveHandler<&COFFMasmParser::IgnoreDirective>(".listmacro");
    addDirectiveHandler<&COFFMasmParser::IgnoreDirective>(".listmacroall");
    addDirectiveHandler<&COFFMasmParser::IgnoreDirective>(".nocref");
    addDirectiveHandler<&COFFMasmParser::IgnoreDirective>(".nolist");
    addDirectiveHandler<&COFFMasmParser::IgnoreDirective>(".nolistif");
    addDirectiveHandler<&COFFMasmParser::IgnoreDirective>(".nolistmacro");
    addDirectiveHandler<&COFFMasmParser::IgnoreDirective>("page");
    addDirectiveHandler<&COFFMasmParser::IgnoreDirective>("subtitle");
    addDirectiveHandler<&COFFMasmParser::IgnoreDirective>(".tfcond");
    addDirectiveHandler<&COFFMasmParser::IgnoreDirective>("title");

    // Macro directives
    // endm
    // exitm
    // goto
    // local
    // macro
    // purge

    // Miscellaneous directives
    // alias
    // assume
    // .fpo
    addDirectiveHandler<&COFFMasmParser::ParseDirectiveIncludelib>(
        "includelib");
    // mmword
    // option
    // popcontext
    // pushcontext
    // .radix
    // .safeseh
    // xmmword
    // ymmword

    // Procedure directives
    addDirectiveHandler<&COFFMasmParser::ParseDirectiveEndProc>("endp");
    // invoke (32-bit only)
    addDirectiveHandler<&COFFMasmParser::ParseDirectiveProc>("proc");
    // proto

    // Processor directives
    addDirectiveHandler<&COFFMasmParser::IgnoreDirective>(".386");
    addDirectiveHandler<&COFFMasmParser::IgnoreDirective>(".386P");
    addDirectiveHandler<&COFFMasmParser::IgnoreDirective>(".387");
    addDirectiveHandler<&COFFMasmParser::IgnoreDirective>(".486");
    addDirectiveHandler<&COFFMasmParser::IgnoreDirective>(".486P");
    addDirectiveHandler<&COFFMasmParser::IgnoreDirective>(".586");
    addDirectiveHandler<&COFFMasmParser::IgnoreDirective>(".586P");
    addDirectiveHandler<&COFFMasmParser::IgnoreDirective>(".686");
    addDirectiveHandler<&COFFMasmParser::IgnoreDirective>(".686P");
    addDirectiveHandler<&COFFMasmParser::IgnoreDirective>(".k3d");
    addDirectiveHandler<&COFFMasmParser::IgnoreDirective>(".mmx");
    addDirectiveHandler<&COFFMasmParser::IgnoreDirective>(".xmm");

    // Repeat blocks directives
    // for
    // forc
    // goto
    // repeat
    // while

    // Scope directives
    // comm
    // externdef

    // Segment directives
    // .alpha (32-bit only, order segments alphabetically)
    // .dosseg (32-bit only, order segments in DOS convention)
    // .seq (32-bit only, order segments sequentially)
    addDirectiveHandler<&COFFMasmParser::ParseDirectiveSegmentEnd>("ends");
    // group (32-bit only)
    addDirectiveHandler<&COFFMasmParser::ParseDirectiveSegment>("segment");

    // Simplified segment directives
    addDirectiveHandler<&COFFMasmParser::ParseSectionDirectiveCode>(".code");
    // .const
    addDirectiveHandler<
        &COFFMasmParser::ParseSectionDirectiveInitializedData>(".data");
    addDirectiveHandler<
        &COFFMasmParser::ParseSectionDirectiveUninitializedData>(".data?");
    // .exit
    // .fardata
    // .fardata?
    addDirectiveHandler<&COFFMasmParser::IgnoreDirective>(".model");
    // .stack
    // .startup

    // String directives, written <name> <directive> <params>
    // catstr (equivalent to <name> TEXTEQU <params>)
    // instr (equivalent to <name> = @InStr(<params>))
    // sizestr (equivalent to <name> = @SizeStr(<params>))
    // substr (equivalent to <name> TEXTEQU @SubStr(<params>))

    // Structure and record directives
    // ends
    // record
    // struct
    // typedef
    // union
  }

  bool ParseSectionDirectiveCode(StringRef, SMLoc) {
    return ParseSectionSwitch(".text",
                              COFF::IMAGE_SCN_CNT_CODE
                            | COFF::IMAGE_SCN_MEM_EXECUTE
                            | COFF::IMAGE_SCN_MEM_READ,
                              SectionKind::getText());
  }

  bool ParseSectionDirectiveInitializedData(StringRef, SMLoc) {
    return ParseSectionSwitch(".data",
                              COFF::IMAGE_SCN_CNT_INITIALIZED_DATA
                            | COFF::IMAGE_SCN_MEM_READ
                            | COFF::IMAGE_SCN_MEM_WRITE,
                              SectionKind::getData());
  }

  bool ParseSectionDirectiveUninitializedData(StringRef, SMLoc) {
    return ParseSectionSwitch(".bss",
                              COFF::IMAGE_SCN_CNT_UNINITIALIZED_DATA
                            | COFF::IMAGE_SCN_MEM_READ
                            | COFF::IMAGE_SCN_MEM_WRITE,
                              SectionKind::getBSS());
  }

  StringRef CurrentProcedure;

public:
  COFFMasmParser() = default;
};

} // end anonymous namespace.

static SectionKind computeSectionKind(unsigned Flags) {
  if (Flags & COFF::IMAGE_SCN_MEM_EXECUTE)
    return SectionKind::getText();
  if (Flags & COFF::IMAGE_SCN_MEM_READ &&
      (Flags & COFF::IMAGE_SCN_MEM_WRITE) == 0)
    return SectionKind::getReadOnly();
  return SectionKind::getData();
}

bool COFFMasmParser::ParseSectionSwitch(StringRef Section,
                                        unsigned Characteristics,
                                        SectionKind Kind) {
  return ParseSectionSwitch(Section, Characteristics, Kind, "",
                            (COFF::COMDATType)0);
}

bool COFFMasmParser::ParseSectionSwitch(StringRef Section,
                                        unsigned Characteristics,
                                        SectionKind Kind,
                                        StringRef COMDATSymName,
                                        COFF::COMDATType Type) {
  if (getLexer().isNot(AsmToken::EndOfStatement))
    return TokError("unexpected token in section switching directive");
  Lex();

  getStreamer().SwitchSection(getContext().getCOFFSection(
      Section, Characteristics, Kind, COMDATSymName, Type));

  return false;
}

bool COFFMasmParser::ParseDirectiveSegment(StringRef Directive, SMLoc Loc) {
  StringRef SegmentName;
  if (!getLexer().is(AsmToken::Identifier))
    return TokError("expected identifier in directive");
  SegmentName = getTok().getIdentifier();
  Lex();

  StringRef SectionName = SegmentName;
  SmallVector<char, 247> SectionNameVector;
  unsigned Flags = COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
                   COFF::IMAGE_SCN_MEM_READ | COFF::IMAGE_SCN_MEM_WRITE;
  if (SegmentName == "_TEXT" || SegmentName.startswith("_TEXT$")) {
    if (SegmentName.size() == 5) {
      SectionName = ".text";
    } else {
      SectionName =
          (".text$" + SegmentName.substr(6)).toStringRef(SectionNameVector);
    }
    Flags = COFF::IMAGE_SCN_CNT_CODE | COFF::IMAGE_SCN_MEM_EXECUTE |
            COFF::IMAGE_SCN_MEM_READ;
  }
  SectionKind Kind = computeSectionKind(Flags);
  getStreamer().SwitchSection(getContext().getCOFFSection(
      SectionName, Flags, Kind, "", (COFF::COMDATType)(0)));
  return false;
}

/// ParseDirectiveSegmentEnd
///  ::= identifier "ends"
bool COFFMasmParser::ParseDirectiveSegmentEnd(StringRef Directive, SMLoc Loc) {
  StringRef SegmentName;
  if (!getLexer().is(AsmToken::Identifier))
    return TokError("expected identifier in directive");
  SegmentName = getTok().getIdentifier();

  // Ignore; no action necessary.
  Lex();
  return false;
}

/// ParseDirectiveIncludelib
///  ::= "includelib" identifier
bool COFFMasmParser::ParseDirectiveIncludelib(StringRef Directive, SMLoc Loc) {
  StringRef Lib;
  if (getParser().parseIdentifier(Lib))
    return TokError("expected identifier in includelib directive");

  unsigned Flags = COFF::IMAGE_SCN_MEM_PRELOAD | COFF::IMAGE_SCN_MEM_16BIT;
  SectionKind Kind = computeSectionKind(Flags);
  getStreamer().PushSection();
  getStreamer().SwitchSection(getContext().getCOFFSection(
      ".drectve", Flags, Kind, "", (COFF::COMDATType)(0)));
  getStreamer().emitBytes("/DEFAULTLIB:");
  getStreamer().emitBytes(Lib);
  getStreamer().emitBytes(" ");
  getStreamer().PopSection();
  return false;
}

/// ParseDirectiveProc
/// TODO(epastor): Implement parameters and other attributes.
///  ::= label "proc" [[distance]]
///          statements
///      label "endproc"
bool COFFMasmParser::ParseDirectiveProc(StringRef Directive, SMLoc Loc) {
  StringRef Label;
  if (getParser().parseIdentifier(Label))
    return Error(Loc, "expected identifier for procedure");
  if (getLexer().is(AsmToken::Identifier)) {
    StringRef nextVal = getTok().getString();
    SMLoc nextLoc = getTok().getLoc();
    if (nextVal.equals_lower("far")) {
      // TODO(epastor): Handle far procedure definitions.
      Lex();
      return Error(nextLoc, "far procedure definitions not yet supported");
    } else if (nextVal.equals_lower("near")) {
      Lex();
      nextVal = getTok().getString();
      nextLoc = getTok().getLoc();
    }
  }
  MCSymbol *Sym = getContext().getOrCreateSymbol(Label);

  // Define symbol as simple function
  getStreamer().BeginCOFFSymbolDef(Sym);
  getStreamer().EmitCOFFSymbolStorageClass(2);
  getStreamer().EmitCOFFSymbolType(0x20);
  getStreamer().EndCOFFSymbolDef();

  getStreamer().emitLabel(Sym, Loc);
  CurrentProcedure = Label;
  return false;
}
bool COFFMasmParser::ParseDirectiveEndProc(StringRef Directive, SMLoc Loc) {
  StringRef Label;
  SMLoc LabelLoc = getTok().getLoc();
  if (getParser().parseIdentifier(Label))
    return Error(LabelLoc, "expected identifier for procedure end");

  if (CurrentProcedure.empty())
    return Error(Loc, "endp outside of procedure block");
  else if (CurrentProcedure != Label)
    return Error(LabelLoc, "endp does not match current procedure '" +
                               CurrentProcedure + "'");
  return false;
}

namespace llvm {

MCAsmParserExtension *createCOFFMasmParser() { return new COFFMasmParser; }

} // end namespace llvm