Path.cpp

Go to the documentation of this file.

//===- Path.cpp - Path Utilities --------------------------------*- C++ -*-===//
//
// 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
//
//===----------------------------------------------------------------------===//
//
// Utilities for file system path handling, supplementing the ones from
// llvm::sys::path.
//
//===----------------------------------------------------------------------===//
 
#include "circt/Support/Path.h"
#include "mlir/IR/Diagnostics.h"
#include "mlir/Support/FileUtilities.h"
#include "llvm/Support/FileSystem.h"
#include "llvm/Support/Path.h"
 
using namespace circt;
 
/// Append a path to an existing path, replacing it if the other path is
/// absolute. This mimicks the behaviour of `foo/bar` and `/foo/bar` being used
/// in a working directory `/home`, resulting in `/home/foo/bar` and `/foo/bar`,
/// respectively.
void circt::appendPossiblyAbsolutePath(llvm::SmallVectorImpl<char> &base,
                                       const llvm::Twine &suffix) {
  if (llvm::sys::path::is_absolute(suffix)) {
    base.clear();
    suffix.toVector(base);
  } else {
    llvm::sys::path::append(base, suffix);
  }
}
 
void circt::makeCommonDirectoryPrefix(llvm::SmallVectorImpl<char> &a,
                                      StringRef b) {
  // Truncate `a` to the common character prefix of `a` and `b`.
  StringRef aRef(a.data(), a.size());
  size_t e = std::min(aRef.size(), b.size());
  size_t i = 0;
  for (; i < e; ++i)
    if (aRef[i] != b[i])
      break;
  a.truncate(i);
 
  // Truncate `a` so it ends on a directory separator.
  auto sep = llvm::sys::path::get_separator();
  StringRef sepRef(sep);
  while (!a.empty() && !StringRef(a.data(), a.size()).ends_with(sepRef))
    a.pop_back();
}
 
std::unique_ptr<llvm::ToolOutputFile>
circt::createOutputFile(StringRef filename, StringRef dirname,
                        function_ref<InFlightDiagnostic()> emitError) {
  // Determine the output path from the output directory and filename.
  SmallString<128> outputFilename(dirname);
  appendPossiblyAbsolutePath(outputFilename, filename);
  auto outputDir = llvm::sys::path::parent_path(outputFilename);
 
  // Create the output directory if needed.
  std::error_code error = llvm::sys::fs::create_directories(outputDir);
  if (error) {
    emitError() << "cannot create output directory \"" << outputDir
                << "\": " << error.message();
    return {};
  }
 
  // Open the output file.
  std::string errorMessage;
  auto output = mlir::openOutputFile(outputFilename, &errorMessage);
  if (!output)
    emitError() << errorMessage;
  return output;
}