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      1 //===- Main.cpp - Top-Level TableGen implementation -----------------------===//
      2 //
      3 //                     The LLVM Compiler Infrastructure
      4 //
      5 // This file is distributed under the University of Illinois Open Source
      6 // License. See LICENSE.TXT for details.
      7 //
      8 //===----------------------------------------------------------------------===//
      9 //
     10 // TableGen is a tool which can be used to build up a description of something,
     11 // then invoke one or more "tablegen backends" to emit information about the
     12 // description in some predefined format.  In practice, this is used by the LLVM
     13 // code generators to automate generation of a code generator through a
     14 // high-level description of the target.
     15 //
     16 //===----------------------------------------------------------------------===//
     17 
     18 #include "llvm/TableGen/Main.h"
     19 #include "TGParser.h"
     20 #include "llvm/Support/CommandLine.h"
     21 #include "llvm/Support/FileSystem.h"
     22 #include "llvm/Support/MemoryBuffer.h"
     23 #include "llvm/Support/ToolOutputFile.h"
     24 #include "llvm/TableGen/Error.h"
     25 #include "llvm/TableGen/Record.h"
     26 #include <algorithm>
     27 #include <cstdio>
     28 #include <system_error>
     29 using namespace llvm;
     30 
     31 static cl::opt<std::string>
     32 OutputFilename("o", cl::desc("Output filename"), cl::value_desc("filename"),
     33                cl::init("-"));
     34 
     35 static cl::opt<std::string>
     36 DependFilename("d",
     37                cl::desc("Dependency filename"),
     38                cl::value_desc("filename"),
     39                cl::init(""));
     40 
     41 static cl::opt<std::string>
     42 InputFilename(cl::Positional, cl::desc("<input file>"), cl::init("-"));
     43 
     44 static cl::list<std::string>
     45 IncludeDirs("I", cl::desc("Directory of include files"),
     46             cl::value_desc("directory"), cl::Prefix);
     47 
     48 /// \brief Create a dependency file for `-d` option.
     49 ///
     50 /// This functionality is really only for the benefit of the build system.
     51 /// It is similar to GCC's `-M*` family of options.
     52 static int createDependencyFile(const TGParser &Parser, const char *argv0) {
     53   if (OutputFilename == "-") {
     54     errs() << argv0 << ": the option -d must be used together with -o\n";
     55     return 1;
     56   }
     57   std::error_code EC;
     58   tool_output_file DepOut(DependFilename, EC, sys::fs::F_Text);
     59   if (EC) {
     60     errs() << argv0 << ": error opening " << DependFilename << ":"
     61            << EC.message() << "\n";
     62     return 1;
     63   }
     64   DepOut.os() << OutputFilename << ":";
     65   for (const auto &Dep : Parser.getDependencies()) {
     66     DepOut.os() << ' ' << Dep.first;
     67   }
     68   DepOut.os() << "\n";
     69   DepOut.keep();
     70   return 0;
     71 }
     72 
     73 int llvm::TableGenMain(char *argv0, TableGenMainFn *MainFn) {
     74   RecordKeeper Records;
     75 
     76   // Parse the input file.
     77   ErrorOr<std::unique_ptr<MemoryBuffer>> FileOrErr =
     78       MemoryBuffer::getFileOrSTDIN(InputFilename);
     79   if (std::error_code EC = FileOrErr.getError()) {
     80     errs() << "Could not open input file '" << InputFilename
     81            << "': " << EC.message() << "\n";
     82     return 1;
     83   }
     84 
     85   // Tell SrcMgr about this buffer, which is what TGParser will pick up.
     86   SrcMgr.AddNewSourceBuffer(std::move(*FileOrErr), SMLoc());
     87 
     88   // Record the location of the include directory so that the lexer can find
     89   // it later.
     90   SrcMgr.setIncludeDirs(IncludeDirs);
     91 
     92   TGParser Parser(SrcMgr, Records);
     93 
     94   if (Parser.ParseFile())
     95     return 1;
     96 
     97   std::error_code EC;
     98   tool_output_file Out(OutputFilename, EC, sys::fs::F_Text);
     99   if (EC) {
    100     errs() << argv0 << ": error opening " << OutputFilename << ":"
    101            << EC.message() << "\n";
    102     return 1;
    103   }
    104   if (!DependFilename.empty()) {
    105     if (int Ret = createDependencyFile(Parser, argv0))
    106       return Ret;
    107   }
    108 
    109   if (MainFn(Out.os(), Records))
    110     return 1;
    111 
    112   if (ErrorsPrinted > 0) {
    113     errs() << argv0 << ": " << ErrorsPrinted << " errors.\n";
    114     return 1;
    115   }
    116 
    117   // Declare success.
    118   Out.keep();
    119   return 0;
    120 }
    121