Introduce a new clang-cc option

  -remap-file=from;to

which takes the file "from" and transparently replaces its contents
with the contents of the file "to" from the source manager's
perspective. This is the moral equivalent of

  cp from saved
  cp to from
  <call clang>
  cp saved from
  rm saved

without all of the pesky file copying.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@90307 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 18 insertions, 0 deletions

diff --git a/tools/clang-cc/Options.cpp b/tools/clang-cc/Options.cpp
index a18598ef7c..c97d4ca8c9 100644
--- a/tools/clang-cc/Options.cpp
+++ b/tools/clang-cc/Options.cpp
@@ -673,6 +673,10 @@ static llvm::cl::opt<bool>
 UndefMacros("undef", llvm::cl::value_desc("macro"),
             llvm::cl::desc("undef all system defines"));
 
+static llvm::cl::list<std::string>
+RemappedFiles("remap-file", llvm::cl::value_desc("<from>;<to>"),
+              llvm::cl::desc("replace the contents of the <from> file with the contents of the <to> file"));
+
 }
 
 //===----------------------------------------------------------------------===//
@@ -1071,6 +1075,20 @@ void clang::InitializePreprocessorOptions(PreprocessorOptions &Opts) {
 
   for (unsigned i = 0, e = OrderedPaths.size(); i != e; ++i)
     Opts.Includes.push_back(*OrderedPaths[i].second);
+
+  // Handle file remapping.
+  for (unsigned i = 0, e = RemappedFiles.size(); i != e; ++i) {
+    std::string::size_type Semi = RemappedFiles[i].find(';');
+    if (Semi == std::string::npos) {
+      // FIXME: Don't fail like this.
+      fprintf(stderr, 
+              "error: -remap-file not of the form <from-file>;<to-file>\n");
+      continue;
+    }
+
+    Opts.addRemappedFile(llvm::StringRef(RemappedFiles[i].c_str(), Semi),
+                         llvm::StringRef(RemappedFiles[i].c_str() + Semi + 1));
+  }
 }
 
 void clang::InitializeLangOptions(LangOptions &Options,