Make tooling::applyAllReplacements return llvm::Expected<string> instead of empty string to indicate potential error.

Summary:
return llvm::Expected<> to carry error status and error information.
This is the first step towards introducing "Error" into tooling::Replacements.

Reviewers: djasper, klimek

Subscribers: ioeric, klimek, cfe-commits

Differential Revision: http://reviews.llvm.org/D21601

llvm-svn: 275062

1 files changed, 6 insertions, 3 deletions

diff --git a/clang/tools/clang-format/ClangFormat.cpp b/clang/tools/clang-format/ClangFormat.cpp
index a9b077e0b1a..27577a5a336 100644
--- a/clang/tools/clang-format/ClangFormat.cpp
+++ b/clang/tools/clang-format/ClangFormat.cpp
@@ -257,13 +257,16 @@ static bool format(StringRef FileName) {
   unsigned CursorPosition = Cursor;
   Replacements Replaces = sortIncludes(FormatStyle, Code->getBuffer(), Ranges,
                                        AssumedFileName, &CursorPosition);
-  std::string ChangedCode =
-      tooling::applyAllReplacements(Code->getBuffer(), Replaces);
+  auto ChangedCode = tooling::applyAllReplacements(Code->getBuffer(), Replaces);
+  if (!ChangedCode) {
+    llvm::errs() << llvm::toString(ChangedCode.takeError()) << "\n";
+    return true;
+  }
   for (const auto &R : Replaces)
     Ranges.push_back({R.getOffset(), R.getLength()});
 
   bool IncompleteFormat = false;
-  Replacements FormatChanges = reformat(FormatStyle, ChangedCode, Ranges,
+  Replacements FormatChanges = reformat(FormatStyle, *ChangedCode, Ranges,
                                         AssumedFileName, &IncompleteFormat);
   Replaces = tooling::mergeReplacements(Replaces, FormatChanges);
   if (OutputXML) {