Propagate changes through no-op transforms

Currently, changes made by previous transforms are not kept if a transform
doesn't make any changes itself to a given file. Now file states are propagated
properly through transforms that don't make changes.

Fixes: PR15281
Author: Jack Yang <jack.yang@intel.com>
Reviewer: klimek
llvm-svn: 175288

1 files changed, 8 insertions, 6 deletions

diff --git a/clang-tools-extra/cpp11-migrate/Transform.cpp b/clang-tools-extra/cpp11-migrate/Transform.cpp
index 65205360839..6d48f4bbbc4 100644
--- a/clang-tools-extra/cpp11-migrate/Transform.cpp
+++ b/clang-tools-extra/cpp11-migrate/Transform.cpp
@@ -7,7 +7,11 @@
 using namespace clang;
 
 void collectResults(clang::Rewriter &Rewrite,
+                    const FileContentsByPath &InputStates,
                     FileContentsByPath &Results) {
+  // Copy the contents of InputStates to be modified.
+  Results = InputStates;
+
   for (Rewriter::buffer_iterator I = Rewrite.buffer_begin(),
                                  E = Rewrite.buffer_end();
        I != E; ++I) {
@@ -16,20 +20,18 @@ void collectResults(clang::Rewriter &Rewrite,
     assert(Entry->getName() != 0 &&
            "Unexpected NULL return from FileEntry::getName()");
 
-    FileContentsByPath::value_type ResultEntry;
-
-    ResultEntry.first = Entry->getName();
+    std::string ResultBuf;
 
     // Get a copy of the rewritten buffer from the Rewriter.
-    llvm::raw_string_ostream StringStream(ResultEntry.second);
+    llvm::raw_string_ostream StringStream(ResultBuf);
     I->second.write(StringStream);
 
-    // Cause results to be written to ResultEntry.second.
+    // Cause results to be written to ResultBuf.
     StringStream.str();
 
     // FIXME: Use move semantics to avoid copies of the buffer contents if
     // benchmarking shows the copies are expensive, especially for large source
     // files.
-    Results.push_back(ResultEntry);
+    Results[Entry->getName()] = ResultBuf;
   }
 }