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/ADT/StringExtras.h"
21 #include "llvm/Support/CommandLine.h"
22 #include "llvm/Support/FileSystem.h"
23 #include "llvm/Support/MemoryBuffer.h"
24 #include "llvm/Support/ToolOutputFile.h"
25 #include "llvm/TableGen/Error.h"
26 #include "llvm/TableGen/Record.h"
27 #include <algorithm>
28 #include <cstdio>
29 #include <system_error>
30 using namespace llvm;
31 
32 static cl::opt<std::string>
33 OutputFilename("o", cl::desc("Output filename"), cl::value_desc("filename"),
34                cl::init("-"));
35 
36 static cl::opt<std::string>
37 DependFilename("d",
38                cl::desc("Dependency filename"),
39                cl::value_desc("filename"),
40                cl::init(""));
41 
42 static cl::opt<std::string>
43 InputFilename(cl::Positional, cl::desc("<input file>"), cl::init("-"));
44 
45 static cl::list<std::string>
46 IncludeDirs("I", cl::desc("Directory of include files"),
47             cl::value_desc("directory"), cl::Prefix);
48 
49 static cl::list<std::string>
50 MacroNames("D", cl::desc("Name of the macro to be defined"),
51             cl::value_desc("macro name"), cl::Prefix);
52 
53 static int reportError(const char *ProgName, Twine Msg) {
54   errs() << ProgName << ": " << Msg;
55   errs().flush();
56   return 1;
57 }
58 
59 /// Create a dependency file for `-d` option.
60 ///
61 /// This functionality is really only for the benefit of the build system.
62 /// It is similar to GCC's `-M*` family of options.
63 static int createDependencyFile(const TGParser &Parser, const char *argv0) {
64   if (OutputFilename == "-")
65     return reportError(argv0, "the option -d must be used together with -o\n");
66 
67   std::error_code EC;
68   ToolOutputFile DepOut(DependFilename, EC, sys::fs::F_Text);
69   if (EC)
70     return reportError(argv0, "error opening " + DependFilename + ":" +
71                                   EC.message() + "\n");
72   DepOut.os() << OutputFilename << ":";
73   for (const auto &Dep : Parser.getDependencies()) {
74     DepOut.os() << ' ' << Dep.first;
75   }
76   DepOut.os() << "\n";
77   DepOut.keep();
78   return 0;
79 }
80 
81 int llvm::TableGenMain(char *argv0, TableGenMainFn *MainFn) {
82   RecordKeeper Records;
83 
84   // Parse the input file.
85   ErrorOr<std::unique_ptr<MemoryBuffer>> FileOrErr =
86       MemoryBuffer::getFileOrSTDIN(InputFilename);
87   if (std::error_code EC = FileOrErr.getError())
88     return reportError(argv0, "Could not open input file '" + InputFilename +
89                                   "': " + EC.message() + "\n");
90 
91   // Tell SrcMgr about this buffer, which is what TGParser will pick up.
92   SrcMgr.AddNewSourceBuffer(std::move(*FileOrErr), SMLoc());
93 
94   // Record the location of the include directory so that the lexer can find
95   // it later.
96   SrcMgr.setIncludeDirs(IncludeDirs);
97 
98   TGParser Parser(SrcMgr, MacroNames, Records);
99 
100   if (Parser.ParseFile())
101     return 1;
102 
103   std::error_code EC;
104   ToolOutputFile Out(OutputFilename, EC, sys::fs::F_Text);
105   if (EC)
106     return reportError(argv0, "error opening " + OutputFilename + ":" +
107                                   EC.message() + "\n");
108   if (!DependFilename.empty()) {
109     if (int Ret = createDependencyFile(Parser, argv0))
110       return Ret;
111   }
112 
113   if (MainFn(Out.os(), Records))
114     return 1;
115 
116   if (ErrorsPrinted > 0)
117     return reportError(argv0, Twine(ErrorsPrinted) + " errors.\n");
118 
119   // Declare success.
120   Out.keep();
121   return 0;
122 }
123