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
reportError(const char * ProgName,Twine Msg)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.
createDependencyFile(const TGParser & Parser,const char * argv0)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
TableGenMain(char * argv0,TableGenMainFn * MainFn)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 // Write output to memory.
104 std::string OutString;
105 raw_string_ostream Out(OutString);
106 if (MainFn(Out, Records))
107 return 1;
108
109 // Always write the depfile, even if the main output hasn't changed.
110 // If it's missing, Ninja considers the output dirty. If this was below
111 // the early exit below and someone deleted the .inc.d file but not the .inc
112 // file, tablegen would never write the depfile.
113 if (!DependFilename.empty()) {
114 if (int Ret = createDependencyFile(Parser, argv0))
115 return Ret;
116 }
117
118 // Only updates the real output file if there are any differences.
119 // This prevents recompilation of all the files depending on it if there
120 // aren't any.
121 if (auto ExistingOrErr = MemoryBuffer::getFile(OutputFilename))
122 if (std::move(ExistingOrErr.get())->getBuffer() == Out.str())
123 return 0;
124
125 std::error_code EC;
126 ToolOutputFile OutFile(OutputFilename, EC, sys::fs::F_Text);
127 if (EC)
128 return reportError(argv0, "error opening " + OutputFilename + ":" +
129 EC.message() + "\n");
130 OutFile.os() << Out.str();
131
132 if (ErrorsPrinted > 0)
133 return reportError(argv0, Twine(ErrorsPrinted) + " errors.\n");
134
135 // Declare success.
136 OutFile.keep();
137 return 0;
138 }
139