Import LLVM 10.0.0 release including clang, lld and lldb.

ok hackroom
tested by plenty

1 files changed, 120 insertions, 0 deletions

diff --git a/gnu/llvm/clang/lib/Basic/FileSystemStatCache.cpp b/gnu/llvm/clang/lib/Basic/FileSystemStatCache.cpp
new file mode 100644
index 00000000000..415a4e2025d
--- /dev/null
+++ b/gnu/llvm/clang/lib/Basic/FileSystemStatCache.cpp
@@ -0,0 +1,120 @@
+//===- FileSystemStatCache.cpp - Caching for 'stat' calls -----------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+//
+//  This file defines the FileSystemStatCache interface.
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/Basic/FileSystemStatCache.h"
+#include "llvm/Support/Chrono.h"
+#include "llvm/Support/ErrorOr.h"
+#include "llvm/Support/Path.h"
+#include "llvm/Support/VirtualFileSystem.h"
+#include <utility>
+
+using namespace clang;
+
+void FileSystemStatCache::anchor() {}
+
+/// FileSystemStatCache::get - Get the 'stat' information for the specified
+/// path, using the cache to accelerate it if possible.  This returns true if
+/// the path does not exist or false if it exists.
+///
+/// If isFile is true, then this lookup should only return success for files
+/// (not directories).  If it is false this lookup should only return
+/// success for directories (not files).  On a successful file lookup, the
+/// implementation can optionally fill in FileDescriptor with a valid
+/// descriptor and the client guarantees that it will close it.
+std::error_code
+FileSystemStatCache::get(StringRef Path, llvm::vfs::Status &Status,
+                         bool isFile, std::unique_ptr<llvm::vfs::File> *F,
+                         FileSystemStatCache *Cache,
+                         llvm::vfs::FileSystem &FS) {
+  bool isForDir = !isFile;
+  std::error_code RetCode;
+
+  // If we have a cache, use it to resolve the stat query.
+  if (Cache)
+    RetCode = Cache->getStat(Path, Status, isFile, F, FS);
+  else if (isForDir || !F) {
+    // If this is a directory or a file descriptor is not needed and we have
+    // no cache, just go to the file system.
+    llvm::ErrorOr<llvm::vfs::Status> StatusOrErr = FS.status(Path);
+    if (!StatusOrErr) {
+      RetCode = StatusOrErr.getError();
+    } else {
+      Status = *StatusOrErr;
+    }
+  } else {
+    // Otherwise, we have to go to the filesystem.  We can always just use
+    // 'stat' here, but (for files) the client is asking whether the file exists
+    // because it wants to turn around and *open* it.  It is more efficient to
+    // do "open+fstat" on success than it is to do "stat+open".
+    //
+    // Because of this, check to see if the file exists with 'open'.  If the
+    // open succeeds, use fstat to get the stat info.
+    auto OwnedFile = FS.openFileForRead(Path);
+
+    if (!OwnedFile) {
+      // If the open fails, our "stat" fails.
+      RetCode = OwnedFile.getError();
+    } else {
+      // Otherwise, the open succeeded.  Do an fstat to get the information
+      // about the file.  We'll end up returning the open file descriptor to the
+      // client to do what they please with it.
+      llvm::ErrorOr<llvm::vfs::Status> StatusOrErr = (*OwnedFile)->status();
+      if (StatusOrErr) {
+        Status = *StatusOrErr;
+        *F = std::move(*OwnedFile);
+      } else {
+        // fstat rarely fails.  If it does, claim the initial open didn't
+        // succeed.
+        *F = nullptr;
+        RetCode = StatusOrErr.getError();
+      }
+    }
+  }
+
+  // If the path doesn't exist, return failure.
+  if (RetCode)
+    return RetCode;
+
+  // If the path exists, make sure that its "directoryness" matches the clients
+  // demands.
+  if (Status.isDirectory() != isForDir) {
+    // If not, close the file if opened.
+    if (F)
+      *F = nullptr;
+    return std::make_error_code(
+        Status.isDirectory() ?
+            std::errc::is_a_directory : std::errc::not_a_directory);
+  }
+
+  return std::error_code();
+}
+
+std::error_code
+MemorizeStatCalls::getStat(StringRef Path, llvm::vfs::Status &Status,
+                           bool isFile,
+                           std::unique_ptr<llvm::vfs::File> *F,
+                           llvm::vfs::FileSystem &FS) {
+  auto err = get(Path, Status, isFile, F, nullptr, FS);
+  if (err) {
+    // Do not cache failed stats, it is easy to construct common inconsistent
+    // situations if we do, and they are not important for PCH performance
+    // (which currently only needs the stats to construct the initial
+    // FileManager entries).
+    return err;
+  }
+
+  // Cache file 'stat' results and directories with absolutely paths.
+  if (!Status.isDirectory() || llvm::sys::path::is_absolute(Path))
+    StatCalls[Path] = Status;
+
+  return std::error_code();
+}