[PATCH] D59415: Do not resolve directory junctions for `-fdiagnostics-absolute-paths` on Windows.

[Igor Kudrin via Phabricator via cfe-commits]

ikudrin updated this revision to Diff 200749.
ikudrin edited the summary of this revision.
ikudrin added a comment.

Added a comment explaining the differences in the implementations. I would really appreciate any corrections.


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D59415/new/

https://reviews.llvm.org/D59415

Files:
  lib/Frontend/TextDiagnostic.cpp
  test/Frontend/absolute-paths-windows.test
  test/Frontend/lit.local.cfg


Index: test/Frontend/lit.local.cfg
===================================================================
--- test/Frontend/lit.local.cfg
+++ test/Frontend/lit.local.cfg
@@ -1 +1 @@
-config.suffixes = ['.c', '.cpp', '.m', '.mm', '.ll', '.cl']
+config.suffixes = ['.c', '.cpp', '.m', '.mm', '.ll', '.cl', '.test']
Index: test/Frontend/absolute-paths-windows.test
===================================================================
--- /dev/null
+++ test/Frontend/absolute-paths-windows.test
@@ -0,0 +1,9 @@
+// REQUIRES: system-windows
+// RUN: rm -rf %t.dir
+// RUN: mkdir -p %t.dir\real
+// RUN: cmd /c mklink /j %t.dir\junc %t.dir\real
+// RUN: echo "wrong code" > %t.dir\real\foo.cpp
+// RUN: not %clang_cc1 -fsyntax-only -fdiagnostics-absolute-paths %t.dir\junc\foo.cpp 2>&1 | FileCheck %s
+
+// CHECK-NOT: .dir\real\foo.cpp
+// CHECK: .dir\junc\foo.cpp
Index: lib/Frontend/TextDiagnostic.cpp
===================================================================
--- lib/Frontend/TextDiagnostic.cpp
+++ lib/Frontend/TextDiagnostic.cpp
@@ -765,7 +765,28 @@
     const DirectoryEntry *Dir = SM.getFileManager().getDirectory(
         llvm::sys::path::parent_path(Filename));
     if (Dir) {
+      // We want to print a simplified absolute path, i. e. without "dots".
+      //
+      // The hardest part here are the paths like "<part1>/<link>/../<part2>".
+      // On Unix-like systems, we cannot just collapse "<link>/..", because
+      // paths are resolved sequentially, and, thereby, the path
+      // "<part1>/<part2>" may point to a different location. That is why
+      // we use FileManager::getCanonicalName(), which expands all indirections
+      // with llvm::sys::fs::real_path() and caches the result.
+      //
+      // On the other hand, it would be better to preserve as much of the
+      // original path as possible, because that helps a user to recognize it.
+      // real_path() expands all links, which sometimes too much. Luckily,
+      // on Windows we can just use llvm::sys::path::remove_dots(), because,
+      // on that system, both aforementioned paths point to the same place.
+#ifdef _WIN32
+      SmallString<4096> DirName = Dir->getName();
+      llvm::sys::fs::make_absolute(DirName);
+      llvm::sys::path::native(DirName);
+      llvm::sys::path::remove_dots(DirName, /* remove_dot_dot */ true);
+#else
       StringRef DirName = SM.getFileManager().getCanonicalName(Dir);
+#endif
       llvm::sys::path::append(AbsoluteFilename, DirName,
                               llvm::sys::path::filename(Filename));
       Filename = StringRef(AbsoluteFilename.data(), AbsoluteFilename.size());


-------------- next part --------------
A non-text attachment was scrubbed...
Name: D59415.200749.patch
Type: text/x-patch
Size: 2632 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/cfe-commits/attachments/20190522/6a078d26/attachment.bin>