reference, declarationdefinition
definition → references, declarations, derived classes, virtual overrides
reference to multiple definitions → definitions
unreferenced
    1
    2
    3
    4
    5
    6
    7
    8
    9
   10
   11
   12
   13
   14
   15
   16
   17
   18
   19
   20
   21
   22
   23
   24
   25
   26
   27
   28
   29
   30
   31
   32
   33
   34
   35
   36
   37
   38
   39
   40
   41
   42
   43
   44
   45
   46
   47
   48
   49
   50
   51
   52
   53
   54
   55
   56
   57
   58
   59
   60
   61
   62
   63
   64
   65
   66
   67
   68
   69
   70
   71
   72
   73
   74
   75
   76
   77
   78
   79
   80
   81
   82
   83
   84
   85
   86
   87
   88
   89
   90
   91
   92
   93
   94
   95
   96
   97
   98
   99
  100
  101
  102
  103
  104
  105
  106
  107
  108
  109
  110
  111
  112
  113
  114
  115
  116
  117
  118
  119
  120
  121
  122
  123
  124
  125
  126
  127
  128
  129
  130
  131
  132
  133
  134
  135
  136
  137
  138
  139
  140
  141
  142
//===- Main.cpp - Top-Level TableGen implementation -----------------------===//
//
// 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
//
//===----------------------------------------------------------------------===//
//
// TableGen is a tool which can be used to build up a description of something,
// then invoke one or more "tablegen backends" to emit information about the
// description in some predefined format.  In practice, this is used by the LLVM
// code generators to automate generation of a code generator through a
// high-level description of the target.
//
//===----------------------------------------------------------------------===//

#include "llvm/TableGen/Main.h"
#include "TGParser.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/FileSystem.h"
#include "llvm/Support/MemoryBuffer.h"
#include "llvm/Support/ToolOutputFile.h"
#include "llvm/TableGen/Error.h"
#include "llvm/TableGen/Record.h"
#include <algorithm>
#include <cstdio>
#include <system_error>
using namespace llvm;

static cl::opt<std::string>
OutputFilename("o", cl::desc("Output filename"), cl::value_desc("filename"),
               cl::init("-"));

static cl::opt<std::string>
DependFilename("d",
               cl::desc("Dependency filename"),
               cl::value_desc("filename"),
               cl::init(""));

static cl::opt<std::string>
InputFilename(cl::Positional, cl::desc("<input file>"), cl::init("-"));

static cl::list<std::string>
IncludeDirs("I", cl::desc("Directory of include files"),
            cl::value_desc("directory"), cl::Prefix);

static cl::list<std::string>
MacroNames("D", cl::desc("Name of the macro to be defined"),
            cl::value_desc("macro name"), cl::Prefix);

static cl::opt<bool>
WriteIfChanged("write-if-changed", cl::desc("Only write output if it changed"));

static int reportError(const char *ProgName, Twine Msg) {
  errs() << ProgName << ": " << Msg;
  errs().flush();
  return 1;
}

/// Create a dependency file for `-d` option.
///
/// This functionality is really only for the benefit of the build system.
/// It is similar to GCC's `-M*` family of options.
static int createDependencyFile(const TGParser &Parser, const char *argv0) {
  if (OutputFilename == "-")
    return reportError(argv0, "the option -d must be used together with -o\n");

  std::error_code EC;
  ToolOutputFile DepOut(DependFilename, EC, sys::fs::OF_None);
  if (EC)
    return reportError(argv0, "error opening " + DependFilename + ":" +
                                  EC.message() + "\n");
  DepOut.os() << OutputFilename << ":";
  for (const auto &Dep : Parser.getDependencies()) {
    DepOut.os() << ' ' << Dep.first;
  }
  DepOut.os() << "\n";
  DepOut.keep();
  return 0;
}

int llvm::TableGenMain(char *argv0, TableGenMainFn *MainFn) {
  RecordKeeper Records;

  // Parse the input file.
  ErrorOr<std::unique_ptr<MemoryBuffer>> FileOrErr =
      MemoryBuffer::getFileOrSTDIN(InputFilename);
  if (std::error_code EC = FileOrErr.getError())
    return reportError(argv0, "Could not open input file '" + InputFilename +
                                  "': " + EC.message() + "\n");

  // Tell SrcMgr about this buffer, which is what TGParser will pick up.
  SrcMgr.AddNewSourceBuffer(std::move(*FileOrErr), SMLoc());

  // Record the location of the include directory so that the lexer can find
  // it later.
  SrcMgr.setIncludeDirs(IncludeDirs);

  TGParser Parser(SrcMgr, MacroNames, Records);

  if (Parser.ParseFile())
    return 1;

  // Write output to memory.
  std::string OutString;
  raw_string_ostream Out(OutString);
  if (MainFn(Out, Records))
    return 1;

  // Always write the depfile, even if the main output hasn't changed.
  // If it's missing, Ninja considers the output dirty.  If this was below
  // the early exit below and someone deleted the .inc.d file but not the .inc
  // file, tablegen would never write the depfile.
  if (!DependFilename.empty()) {
    if (int Ret = createDependencyFile(Parser, argv0))
      return Ret;
  }

  if (WriteIfChanged) {
    // Only updates the real output file if there are any differences.
    // This prevents recompilation of all the files depending on it if there
    // aren't any.
    if (auto ExistingOrErr = MemoryBuffer::getFile(OutputFilename))
      if (std::move(ExistingOrErr.get())->getBuffer() == Out.str())
        return 0;
  }

  std::error_code EC;
  ToolOutputFile OutFile(OutputFilename, EC, sys::fs::OF_None);
  if (EC)
    return reportError(argv0, "error opening " + OutputFilename + ":" +
                                  EC.message() + "\n");
  OutFile.os() << Out.str();

  if (ErrorsPrinted > 0)
    return reportError(argv0, Twine(ErrorsPrinted) + " errors.\n");

  // Declare success.
  OutFile.keep();
  return 0;
}