SourceManager: Use the same fake SLocEntry whenever it fails to load

Instead of putting a fake `SLocEntry` at `LoadedSLocEntryTable[Index]`
when it fails to load in `SourceManager::loadSLocEntry`, allocate a fake
one. Unless someone is sniffing the address of the returned `SLocEntry`
(doubtful), this won't be a functionality change. Note that
`SLocEntryLoaded[Index]` wasn't being set to `true` either before or
after this change so no accessor is every going to look at
`LoadedSLocEntryTable[Index]`.

As a side effect, drop the `mutable` from `LoadedSLocEntryTable`.

Differential Revision: https://reviews.llvm.org/D89748

1 files changed, 5 insertions, 3 deletions

diff --git a/clang/lib/Basic/SourceManager.cpp b/clang/lib/Basic/SourceManager.cpp
index 6eae0f0..88f95d1 100644
--- a/clang/lib/Basic/SourceManager.cpp
+++ b/clang/lib/Basic/SourceManager.cpp
@@ -434,9 +434,11 @@ const SrcMgr::SLocEntry &SourceManager::loadSLocEntry(unsigned Index,
     // If the file of the SLocEntry changed we could still have loaded it.
     if (!SLocEntryLoaded[Index]) {
       // Try to recover; create a SLocEntry so the rest of clang can handle it.
-      LoadedSLocEntryTable[Index] = SLocEntry::get(
-          0, FileInfo::get(SourceLocation(), getFakeContentCacheForRecovery(),
-                           SrcMgr::C_User, ""));
+      if (!FakeSLocEntryForRecovery)
+        FakeSLocEntryForRecovery = std::make_unique<SLocEntry>(SLocEntry::get(
+            0, FileInfo::get(SourceLocation(), getFakeContentCacheForRecovery(),
+                             SrcMgr::C_User, "")));
+      return *FakeSLocEntryForRecovery;
     }
   }