LLVM  8.0.1
Main.cpp
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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/ADT/StringExtras.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 
33 OutputFilename("o", cl::desc("Output filename"), cl::value_desc("filename"),
34  cl::init("-"));
35 
37 DependFilename("d",
38  cl::desc("Dependency filename"),
39  cl::value_desc("filename"),
40  cl::init(""));
41 
43 InputFilename(cl::Positional, cl::desc("<input file>"), cl::init("-"));
44 
46 IncludeDirs("I", cl::desc("Directory of include files"),
47  cl::value_desc("directory"), cl::Prefix);
48 
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;
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.
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.
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;
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 }
Represents either an error or a value T.
Definition: ErrorOr.h:57
raw_ostream & errs()
This returns a reference to a raw_ostream for standard error.
This class represents lattice values for constants.
Definition: AllocatorList.h:24
SourceMgr SrcMgr
Definition: Error.cpp:24
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::list< std::string > IncludeDirs("I", cl::desc("Directory of include files"), cl::value_desc("directory"), cl::Prefix)
unsigned ErrorsPrinted
Definition: Error.cpp:25
Twine - A lightweight data structure for efficiently representing the concatenation of temporary valu...
Definition: Twine.h:81
static cl::opt< std::string > OutputFilename("o", cl::desc("Output filename"), cl::value_desc("filename"), cl::init("-"))
This class contains a raw_fd_ostream and adds a few extra features commonly needed for compiler-like ...
unsigned AddNewSourceBuffer(std::unique_ptr< MemoryBuffer > F, SMLoc IncludeLoc)
Add a new source buffer to this source manager.
Definition: SourceMgr.h:152
static cl::opt< std::string > DependFilename("d", cl::desc("Dependency filename"), cl::value_desc("filename"), cl::init(""))
initializer< Ty > init(const Ty &Val)
Definition: CommandLine.h:423
std::error_code getError() const
Definition: ErrorOr.h:160
int TableGenMain(char *argv0, TableGenMainFn *MainFn)
Definition: Main.cpp:81
std::string & str()
Flushes the stream contents to the target string and returns the string&#39;s reference.
Definition: raw_ostream.h:499
const TGLexer::DependenciesMapTy & getDependencies() const
Definition: TGParser.h:133
static int reportError(const char *ProgName, Twine Msg)
Definition: Main.cpp:53
static ErrorOr< std::unique_ptr< MemoryBuffer > > getFileOrSTDIN(const Twine &Filename, int64_t FileSize=-1, bool RequiresNullTerminator=true)
Open the specified file as a MemoryBuffer, or open stdin if the Filename is "-".
bool(raw_ostream &OS, RecordKeeper &Records) TableGenMainFn
Perform the action using Records, and write output to OS.
Definition: Main.h:24
bool ParseFile()
ParseFile - Main entrypoint for parsing a tblgen file.
static cl::opt< std::string > InputFilename(cl::Positional, cl::desc("<input file>"), cl::init("-"))
void keep()
Indicate that the tool&#39;s job wrt this output file has been successful and the file should not be dele...
static ErrorOr< std::unique_ptr< MemoryBuffer > > getFile(const Twine &Filename, int64_t FileSize=-1, bool RequiresNullTerminator=true, bool IsVolatile=false)
Open the specified file as a MemoryBuffer, returning a new MemoryBuffer if successful, otherwise returning null.
A raw_ostream that writes to an std::string.
Definition: raw_ostream.h:483
void setIncludeDirs(const std::vector< std::string > &Dirs)
Definition: SourceMgr.h:112
static int createDependencyFile(const TGParser &Parser, const char *argv0)
Create a dependency file for -d option.
Definition: Main.cpp:63
Represents a location in source code.
Definition: SMLoc.h:24
raw_fd_ostream & os()
Return the contained raw_fd_ostream.