1 files changed, 40 insertions, 15 deletions

diff --git a/lib/Support/LineIterator.cpp b/lib/Support/LineIterator.cpp
index 947a8fb..5baa1a3 100644
--- a/lib/Support/LineIterator.cpp
+++ b/lib/Support/LineIterator.cpp
@@ -12,16 +12,39 @@
 
 using namespace llvm;
 
-line_iterator::line_iterator(const MemoryBuffer &Buffer, char CommentMarker)
+static bool isAtLineEnd(const char *P) {
+  if (*P == '\n')
+    return true;
+  if (*P == '\r' && *(P + 1) == '\n')
+    return true;
+  return false;
+}
+
+static bool skipIfAtLineEnd(const char *&P) {
+  if (*P == '\n') {
+    ++P;
+    return true;
+  }
+  if (*P == '\r' && *(P + 1) == '\n') {
+    P += 2;
+    return true;
+  }
+  return false;
+}
+
+line_iterator::line_iterator(const MemoryBuffer &Buffer, bool SkipBlanks,
+                             char CommentMarker)
     : Buffer(Buffer.getBufferSize() ? &Buffer : nullptr),
-      CommentMarker(CommentMarker), LineNumber(1),
+      CommentMarker(CommentMarker), SkipBlanks(SkipBlanks), LineNumber(1),
       CurrentLine(Buffer.getBufferSize() ? Buffer.getBufferStart() : nullptr,
                   0) {
   // Ensure that if we are constructed on a non-empty memory buffer that it is
   // a null terminated buffer.
   if (Buffer.getBufferSize()) {
     assert(Buffer.getBufferEnd()[0] == '\0');
-    advance();
+    // Make sure we don't skip a leading newline if we're keeping blanks
+    if (SkipBlanks || !isAtLineEnd(Buffer.getBufferStart()))
+      advance();
   }
 }
 
@@ -29,25 +52,27 @@ void line_iterator::advance() {
   assert(Buffer && "Cannot advance past the end!");
 
   const char *Pos = CurrentLine.end();
-  assert(Pos == Buffer->getBufferStart() || *Pos == '\n' || *Pos == '\0');
+  assert(Pos == Buffer->getBufferStart() || isAtLineEnd(Pos) || *Pos == '\0');
 
-  if (CommentMarker == '\0') {
+  if (skipIfAtLineEnd(Pos))
+    ++LineNumber;
+  if (!SkipBlanks && isAtLineEnd(Pos)) {
+    // Nothing to do for a blank line.
+  } else if (CommentMarker == '\0') {
     // If we're not stripping comments, this is simpler.
-    size_t Blanks = 0;
-    while (Pos[Blanks] == '\n')
-      ++Blanks;
-    Pos += Blanks;
-    LineNumber += Blanks;
+    while (skipIfAtLineEnd(Pos))
+      ++LineNumber;
   } else {
     // Skip comments and count line numbers, which is a bit more complex.
     for (;;) {
+      if (isAtLineEnd(Pos) && !SkipBlanks)
+        break;
       if (*Pos == CommentMarker)
         do {
           ++Pos;
-        } while (*Pos != '\0' && *Pos != '\n');
-      if (*Pos != '\n')
+        } while (*Pos != '\0' && !isAtLineEnd(Pos));
+      if (!skipIfAtLineEnd(Pos))
         break;
-      ++Pos;
       ++LineNumber;
     }
   }
@@ -61,9 +86,9 @@ void line_iterator::advance() {
 
   // Measure the line.
   size_t Length = 0;
-  do {
+  while (Pos[Length] != '\0' && !isAtLineEnd(&Pos[Length])) {
     ++Length;
-  } while (Pos[Length] != '\0' && Pos[Length] != '\n');
+  }
 
   CurrentLine = StringRef(Pos, Length);
 }