1 files changed, 142 insertions, 0 deletions
diff --git a/llvm/lib/TableGen/Main.cpp b/llvm/lib/TableGen/Main.cpp
new file mode 100644
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+++ b/llvm/lib/TableGen/Main.cpp
@@ -0,0 +1,142 @@
+//===- 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;
+}