Use a non-recursive implementation to reconstruct line breaks.

Now that the TokenAnnotator does not require stack space anymore,
reconstructing the lines has become the limiting factor. This patch
fixes that problem, allowing large files with multiple megabytes of
single unwrapped lines to be formatted.

llvm-svn: 182861

1 files changed, 17 insertions, 16 deletions

diff --git a/clang/lib/Format/Format.cpp b/clang/lib/Format/Format.cpp
index 6fc0da58c23..b6e8079b31a 100644
--- a/clang/lib/Format/Format.cpp
+++ b/clang/lib/Format/Format.cpp
@@ -949,22 +949,23 @@ private:
   }
 
   void reconstructPath(LineState &State, StateNode *Current) {
-    // FIXME: This recursive implementation limits the possible number
-    // of tokens per line if compiled into a binary with small stack space.
-    // To become more independent of stack frame limitations we would need
-    // to also change the TokenAnnotator.
-    if (Current->Previous == NULL)
-      return;
-    reconstructPath(State, Current->Previous);
-    DEBUG({
-      if (Current->NewLine) {
-        llvm::dbgs() << "Penalty for splitting before "
-                     << Current->Previous->State.NextToken->Tok.getName()
-                     << ": " << Current->Previous->State.NextToken->SplitPenalty
-                     << "\n";
-      }
-    });
-    addTokenToState(Current->NewLine, false, State);
+    std::deque<StateNode *> Path;
+    // We do not need a break before the initial token.
+    while (Current->Previous) {
+      Path.push_front(Current);
+      Current = Current->Previous;
+    }
+    for (std::deque<StateNode *>::iterator I = Path.begin(), E = Path.end();
+         I != E; ++I) {
+      DEBUG({
+        if ((*I)->NewLine) {
+          llvm::dbgs() << "Penalty for splitting before "
+                       << (*I)->Previous->State.NextToken->Tok.getName() << ": "
+                       << (*I)->Previous->State.NextToken->SplitPenalty << "\n";
+        }
+      });
+      addTokenToState((*I)->NewLine, false, State);
+    }
   }
 
   /// \brief Add the following state to the analysis queue \c Queue.