ADT: Use 'using' to inherit assign and append in SmallString

Rather than reimplement, use a `using` declaration to bring in
`SmallVectorImpl<char>`'s assign and append implementations in
`SmallString`.

The `SmallString` versions were missing reference invalidation
assertions from `SmallVector`. This patch also fixes a bug in
`llvm::FileCollector::addFileImpl`, which was a copy/paste from
`clang::ModuleDependencyCollector::copyToRoot`, both caught by the
no-longer-skipped assertions.

As a drive-by, this also sinks the `const SmallVectorImpl&` versions of
these methods down into `SmallVectorImpl`, since I imagine they'd be
useful elsewhere.

Differential Revision: https://reviews.llvm.org/D95202

1 files changed, 4 insertions, 3 deletions

diff --git a/llvm/lib/Support/FileCollector.cpp b/llvm/lib/Support/FileCollector.cpp
index d0471ac..cb53878 100644
--- a/llvm/lib/Support/FileCollector.cpp
+++ b/llvm/lib/Support/FileCollector.cpp
@@ -86,17 +86,18 @@ void FileCollector::addFileImpl(StringRef SrcPath) {
   sys::path::native(AbsoluteSrc);
 
   // Remove redundant leading "./" pieces and consecutive separators.
-  AbsoluteSrc = sys::path::remove_leading_dotslash(AbsoluteSrc);
+  StringRef TrimmedAbsoluteSrc =
+      sys::path::remove_leading_dotslash(AbsoluteSrc);
 
   // Canonicalize the source path by removing "..", "." components.
-  SmallString<256> VirtualPath = AbsoluteSrc;
+  SmallString<256> VirtualPath = TrimmedAbsoluteSrc;
   sys::path::remove_dots(VirtualPath, /*remove_dot_dot=*/true);
 
   // If a ".." component is present after a symlink component, remove_dots may
   // lead to the wrong real destination path. Let the source be canonicalized
   // like that but make sure we always use the real path for the destination.
   SmallString<256> CopyFrom;
-  if (!getRealPath(AbsoluteSrc, CopyFrom))
+  if (!getRealPath(TrimmedAbsoluteSrc, CopyFrom))
     CopyFrom = VirtualPath;
 
   SmallString<256> DstPath = StringRef(Root);