[PATCH] D100428: [clang][FileManager] Support empty file name in getVirtualFileRef for serialized diagnostics

[Alex Lorenz via Phabricator via cfe-commits]

arphaman created this revision.
arphaman added reviewers: dexonsmith, Bigcheese.
Herald added a subscriber: ributzka.
arphaman requested review of this revision.
Herald added a project: clang.

After https://reviews.llvm.org/D90484 libclang is unable to read a serialized diagnostic file which contains a diagnostic which came from a file with an empty filename. The reason being is that the serialized diagnostic reader is creating a virtual file for the "" filename, which now fails after the changes in https://reviews.llvm.org/D90484. This patch restores the previous behavior in `getVirtualFileRef` by allowing it to construct a file entry ref with an empty name by pretending its name is "." so that the directory entry can be created.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D100428

Files:
  clang/lib/Basic/FileManager.cpp
  clang/test/Misc/serialized-diags-empty-filename.c


Index: clang/test/Misc/serialized-diags-empty-filename.c
===================================================================
--- /dev/null
+++ clang/test/Misc/serialized-diags-empty-filename.c
@@ -0,0 +1,8 @@
+// RUN: rm -f %t.diag
+// RUN: not %clang -c %s --serialize-diagnostics %t.diag
+// RUN: c-index-test -read-diagnostics %t.diag 2>&1 | FileCheck %s
+
+# 1 "" 1
+void 1();
+
+// CHECK: :1:6: error:
Index: clang/lib/Basic/FileManager.cpp
===================================================================
--- clang/lib/Basic/FileManager.cpp
+++ clang/lib/Basic/FileManager.cpp
@@ -387,8 +387,8 @@
   // Now that all ancestors of Filename are in the cache, the
   // following call is guaranteed to find the DirectoryEntry from the
   // cache.
-  auto DirInfo = expectedToOptional(
-      getDirectoryFromFile(*this, Filename, /*CacheFailure=*/true));
+  auto DirInfo = expectedToOptional(getDirectoryFromFile(
+      *this, Filename.empty() ? "." : Filename, /*CacheFailure=*/true));
   assert(DirInfo &&
          "The directory of a virtual file should already be in the cache.");
 


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