Support: Allow use of MemoryBufferRef with line_iterator

Split out from https://reviews.llvm.org/D66782, use `Optional<MemoryBufferRef>`
in `line_iterator` so you don't need access to a `MemoryBuffer*`.  Follow up
patches in `clang/` will leverage this.

Differential Revision: https://reviews.llvm.org/D89280

1 files changed, 6 insertions, 2 deletions

diff --git a/llvm/lib/Support/LineIterator.cpp b/llvm/lib/Support/LineIterator.cpp
index 164436a..7bdf127 100644
--- a/llvm/lib/Support/LineIterator.cpp
+++ b/llvm/lib/Support/LineIterator.cpp
@@ -33,7 +33,11 @@ static bool skipIfAtLineEnd(const char *&P) {
 
 line_iterator::line_iterator(const MemoryBuffer &Buffer, bool SkipBlanks,
                              char CommentMarker)
-    : Buffer(Buffer.getBufferSize() ? &Buffer : nullptr),
+    : line_iterator(Buffer.getMemBufferRef(), SkipBlanks, CommentMarker) {}
+
+line_iterator::line_iterator(const MemoryBufferRef &Buffer, bool SkipBlanks,
+                             char CommentMarker)
+    : Buffer(Buffer.getBufferSize() ? Optional<MemoryBufferRef>(Buffer) : None),
       CommentMarker(CommentMarker), SkipBlanks(SkipBlanks), LineNumber(1),
       CurrentLine(Buffer.getBufferSize() ? Buffer.getBufferStart() : nullptr,
                   0) {
@@ -78,7 +82,7 @@ void line_iterator::advance() {
 
   if (*Pos == '\0') {
     // We've hit the end of the buffer, reset ourselves to the end state.
-    Buffer = nullptr;
+    Buffer = None;
     CurrentLine = StringRef();
     return;
   }