Remove 'const' from MemoryBuffers used through the SourceManager

This removes a const_cast added in r211884 that occurred due to an
inconsistency in how MemoryBuffers are handled between some parts of
clang and LLVM.

MemoryBuffers are immutable and the general convention in the LLVM
project is to omit const from immutable types as it's simply
redundant/verbose (see llvm::Type, for example). While this change
doesn't remove "const" from /every/ MemoryBuffer, it at least makes this
chain of ownership/usage consistent.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@211915 91177308-0d34-0410-b5e6-96231b3b80d8

12 files changed, 63 insertions, 76 deletions

diff --git a/include/clang/Basic/SourceManager.h b/include/clang/Basic/SourceManager.h
index 585d13855e..bece66d427 100644
--- a/include/clang/Basic/SourceManager.h
+++ b/include/clang/Basic/SourceManager.h
@@ -104,7 +104,7 @@ namespace SrcMgr {
     ///
     /// This is owned by the ContentCache object.  The bits indicate
     /// whether the buffer is invalid.
-    mutable llvm::PointerIntPair<const llvm::MemoryBuffer *, 2> Buffer;
+    mutable llvm::PointerIntPair<llvm::MemoryBuffer *, 2> Buffer;
 
   public:
     /// \brief Reference to the file entry representing this ContentCache.
@@ -182,10 +182,10 @@ namespace SrcMgr {
     ///   will be emitted at.
     ///
     /// \param Invalid If non-NULL, will be set \c true if an error occurred.
-    const llvm::MemoryBuffer *getBuffer(DiagnosticsEngine &Diag,
-                                        const SourceManager &SM,
-                                        SourceLocation Loc = SourceLocation(),
-                                        bool *Invalid = nullptr) const;
+    llvm::MemoryBuffer *getBuffer(DiagnosticsEngine &Diag,
+                                  const SourceManager &SM,
+                                  SourceLocation Loc = SourceLocation(),
+                                  bool *Invalid = nullptr) const;
 
     /// \brief Returns the size of the content encapsulated by this
     /// ContentCache.
@@ -205,7 +205,7 @@ namespace SrcMgr {
     /// this content cache.  This is used for performance analysis.
     llvm::MemoryBuffer::BufferKind getMemoryBufferKind() const;
 
-    void setBuffer(const llvm::MemoryBuffer *B) {
+    void setBuffer(llvm::MemoryBuffer *B) {
       assert(!Buffer.getPointer() && "MemoryBuffer already set.");
       Buffer.setPointer(B);
       Buffer.setInt(false);
@@ -213,13 +213,11 @@ namespace SrcMgr {
 
     /// \brief Get the underlying buffer, returning NULL if the buffer is not
     /// yet available.
-    const llvm::MemoryBuffer *getRawBuffer() const {
-      return Buffer.getPointer();
-    }
+    llvm::MemoryBuffer *getRawBuffer() const { return Buffer.getPointer(); }
 
     /// \brief Replace the existing buffer (which will be deleted)
     /// with the given buffer.
-    void replaceBuffer(const llvm::MemoryBuffer *B, bool DoNotFree = false);
+    void replaceBuffer(llvm::MemoryBuffer *B, bool DoNotFree = false);
 
     /// \brief Determine whether the buffer itself is invalid.
     bool isBufferInvalid() const {
@@ -790,7 +788,7 @@ public:
   ///
   /// This does no caching of the buffer and takes ownership of the
   /// MemoryBuffer, so only pass a MemoryBuffer to this once.
-  FileID createFileID(const llvm::MemoryBuffer *Buffer,
+  FileID createFileID(llvm::MemoryBuffer *Buffer,
                       SrcMgr::CharacteristicKind FileCharacter = SrcMgr::C_User,
                       int LoadedID = 0, unsigned LoadedOffset = 0,
                       SourceLocation IncludeLoc = SourceLocation()) {
@@ -820,8 +818,8 @@ public:
   ///
   /// \param Invalid If non-NULL, will be set \c true if an error
   /// occurs while retrieving the memory buffer.
-  const llvm::MemoryBuffer *getMemoryBufferForFile(const FileEntry *File,
-                                                   bool *Invalid = nullptr);
+  llvm::MemoryBuffer *getMemoryBufferForFile(const FileEntry *File,
+                                             bool *Invalid = nullptr);
 
   /// \brief Override the contents of the given source file by providing an
   /// already-allocated buffer.
@@ -834,8 +832,7 @@ public:
   /// \param DoNotFree If true, then the buffer will not be freed when the
   /// source manager is destroyed.
   void overrideFileContents(const FileEntry *SourceFile,
-                            const llvm::MemoryBuffer *Buffer,
-                            bool DoNotFree = false);
+                            llvm::MemoryBuffer *Buffer, bool DoNotFree = false);
 
   /// \brief Override the given source file with another one.
   ///
@@ -872,8 +869,8 @@ public:
   ///
   /// If there is an error opening this buffer the first time, this
   /// manufactures a temporary buffer and returns a non-empty error string.
-  const llvm::MemoryBuffer *getBuffer(FileID FID, SourceLocation Loc,
-                                      bool *Invalid = nullptr) const {
+  llvm::MemoryBuffer *getBuffer(FileID FID, SourceLocation Loc,
+                                bool *Invalid = nullptr) const {
     bool MyInvalid = false;
     const SrcMgr::SLocEntry &Entry = getSLocEntry(FID, &MyInvalid);
     if (MyInvalid || !Entry.isFile()) {
@@ -887,8 +884,7 @@ public:
                                                         Invalid);
   }
 
-  const llvm::MemoryBuffer *getBuffer(FileID FID,
-                                      bool *Invalid = nullptr) const {
+  llvm::MemoryBuffer *getBuffer(FileID FID, bool *Invalid = nullptr) const {
     bool MyInvalid = false;
     const SrcMgr::SLocEntry &Entry = getSLocEntry(FID, &MyInvalid);
     if (MyInvalid || !Entry.isFile()) {
@@ -1557,7 +1553,7 @@ public:
   }
 
 private:
-  const llvm::MemoryBuffer *getFakeBufferForRecovery() const;
+  llvm::MemoryBuffer *getFakeBufferForRecovery() const;
   const SrcMgr::ContentCache *getFakeContentCacheForRecovery() const;
 
   const SrcMgr::SLocEntry &loadSLocEntry(unsigned Index, bool *Invalid) const;
@@ -1626,8 +1622,8 @@ private:
                             bool isSystemFile = false);
 
   /// \brief Create a new ContentCache for the specified  memory buffer.
-  const SrcMgr::ContentCache*
-  createMemBufferContentCache(const llvm::MemoryBuffer *Buf);
+  const SrcMgr::ContentCache *
+  createMemBufferContentCache(llvm::MemoryBuffer *Buf);
 
   FileID getFileIDSlow(unsigned SLocOffset) const;
   FileID getFileIDLocal(unsigned SLocOffset) const;
diff --git a/include/clang/Frontend/ASTUnit.h b/include/clang/Frontend/ASTUnit.h
index 3d7d0f2796..d5d6d49bde 100644
--- a/include/clang/Frontend/ASTUnit.h
+++ b/include/clang/Frontend/ASTUnit.h
@@ -692,7 +692,7 @@ public:
 
   /// \brief A mapping from a file name to the memory buffer that stores the
   /// remapped contents of that file.
-  typedef std::pair<std::string, const llvm::MemoryBuffer *> RemappedFile;
+  typedef std::pair<std::string, llvm::MemoryBuffer *> RemappedFile;
 
   /// \brief Create a ASTUnit. Gets ownership of the passed CompilerInvocation. 
   static ASTUnit *create(CompilerInvocation *CI,
diff --git a/include/clang/Lex/PreprocessorOptions.h b/include/clang/Lex/PreprocessorOptions.h
index eba2a13342..1ab5a3e8eb 100644
--- a/include/clang/Lex/PreprocessorOptions.h
+++ b/include/clang/Lex/PreprocessorOptions.h
@@ -102,9 +102,8 @@ public:
   /// \brief The set of file-to-buffer remappings, which take existing files
   /// on the system (the first part of each pair) and gives them the contents
   /// of the specified memory buffer (the second part of each pair).
-  std::vector<std::pair<std::string, const llvm::MemoryBuffer *> > 
-    RemappedFileBuffers;
-  
+  std::vector<std::pair<std::string, llvm::MemoryBuffer *>> RemappedFileBuffers;
+
   /// \brief Whether the compiler instance should retain (i.e., not free)
   /// the buffers associated with remapped files.
   ///
@@ -157,10 +156,11 @@ public:
     return RemappedFiles.end();
   }
 
-  typedef std::vector<std::pair<std::string, const llvm::MemoryBuffer *> >::
-                                  iterator remapped_file_buffer_iterator;
-  typedef std::vector<std::pair<std::string, const llvm::MemoryBuffer *> >::
-                            const_iterator const_remapped_file_buffer_iterator;
+  typedef std::vector<std::pair<std::string, llvm::MemoryBuffer *>>::iterator
+  remapped_file_buffer_iterator;
+  typedef std::vector<
+      std::pair<std::string, llvm::MemoryBuffer *>>::const_iterator
+  const_remapped_file_buffer_iterator;
   remapped_file_buffer_iterator remapped_file_buffer_begin() {
     return RemappedFileBuffers.begin();
   }
@@ -197,8 +197,8 @@ public:
   remapped_file_iterator eraseRemappedFile(remapped_file_iterator Remapped) {
     return RemappedFiles.erase(Remapped);
   }
-  
-  void addRemappedFile(StringRef From, const llvm::MemoryBuffer * To) {
+
+  void addRemappedFile(StringRef From, llvm::MemoryBuffer *To) {
     RemappedFileBuffers.push_back(std::make_pair(From, To));
   }
   
diff --git a/lib/Basic/SourceManager.cpp b/lib/Basic/SourceManager.cpp
index d2d556288d..5d36f6c8a0 100644
--- a/lib/Basic/SourceManager.cpp
+++ b/lib/Basic/SourceManager.cpp
@@ -55,8 +55,8 @@ llvm::MemoryBuffer::BufferKind ContentCache::getMemoryBufferKind() const {
   // Should be unreachable, but keep for sanity.
   if (!Buffer.getPointer())
     return llvm::MemoryBuffer::MemoryBuffer_Malloc;
-  
-  const llvm::MemoryBuffer *buf = Buffer.getPointer();
+
+  llvm::MemoryBuffer *buf = Buffer.getPointer();
   return buf->getBufferKind();
 }
 
@@ -69,8 +69,7 @@ unsigned ContentCache::getSize() const {
                              : (unsigned) ContentsEntry->getSize();
 }
 
-void ContentCache::replaceBuffer(const llvm::MemoryBuffer *B,
-                                 bool DoNotFree) {
+void ContentCache::replaceBuffer(llvm::MemoryBuffer *B, bool DoNotFree) {
   if (B && B == Buffer.getPointer()) {
     assert(0 && "Replacing with the same buffer");
     Buffer.setInt(DoNotFree? DoNotFreeFlag : 0);
@@ -83,10 +82,10 @@ void ContentCache::replaceBuffer(const llvm::MemoryBuffer *B,
   Buffer.setInt(DoNotFree? DoNotFreeFlag : 0);
 }
 
-const llvm::MemoryBuffer *ContentCache::getBuffer(DiagnosticsEngine &Diag,
-                                                  const SourceManager &SM,
-                                                  SourceLocation Loc,
-                                                  bool *Invalid) const {
+llvm::MemoryBuffer *ContentCache::getBuffer(DiagnosticsEngine &Diag,
+                                            const SourceManager &SM,
+                                            SourceLocation Loc,
+                                            bool *Invalid) const {
   // Lazily create the Buffer for ContentCaches that wrap files.  If we already
   // computed it, just return what we have.
   if (Buffer.getPointer() || !ContentsEntry) {
@@ -462,8 +461,8 @@ SourceManager::getOrCreateContentCache(const FileEntry *FileEnt,
 
 /// createMemBufferContentCache - Create a new ContentCache for the specified
 ///  memory buffer.  This does no caching.
-const ContentCache*
-SourceManager::createMemBufferContentCache(const MemoryBuffer *Buffer) {
+const ContentCache *
+SourceManager::createMemBufferContentCache(llvm::MemoryBuffer *Buffer) {
   // Add a new ContentCache to the MemBufferInfos list and return it.
   ContentCache *Entry = ContentCacheAlloc.Allocate<ContentCache>();
   new (Entry) ContentCache();
@@ -505,7 +504,7 @@ SourceManager::AllocateLoadedSLocEntries(unsigned NumSLocEntries,
 
 /// \brief As part of recovering from missing or changed content, produce a
 /// fake, non-empty buffer.
-const llvm::MemoryBuffer *SourceManager::getFakeBufferForRecovery() const {
+llvm::MemoryBuffer *SourceManager::getFakeBufferForRecovery() const {
   if (!FakeBufferForRecovery)
     FakeBufferForRecovery
       = llvm::MemoryBuffer::getMemBuffer("<<<INVALID BUFFER>>");
@@ -644,16 +643,15 @@ SourceManager::createExpansionLocImpl(const ExpansionInfo &Info,
   return SourceLocation::getMacroLoc(NextLocalOffset - (TokLength + 1));
 }
 
-const llvm::MemoryBuffer *
-SourceManager::getMemoryBufferForFile(const FileEntry *File,
-                                      bool *Invalid) {
+llvm::MemoryBuffer *SourceManager::getMemoryBufferForFile(const FileEntry *File,
+                                                          bool *Invalid) {
   const SrcMgr::ContentCache *IR = getOrCreateContentCache(File);
   assert(IR && "getOrCreateContentCache() cannot return NULL");
   return IR->getBuffer(Diag, *this, SourceLocation(), Invalid);
 }
 
 void SourceManager::overrideFileContents(const FileEntry *SourceFile,
-                                         const llvm::MemoryBuffer *Buffer,
+                                         llvm::MemoryBuffer *Buffer,
                                          bool DoNotFree) {
   const SrcMgr::ContentCache *IR = getOrCreateContentCache(SourceFile);
   assert(IR && "getOrCreateContentCache() cannot return NULL");
@@ -696,10 +694,9 @@ StringRef SourceManager::getBufferData(FileID FID, bool *Invalid) const {
       *Invalid = true;
     return "<<<<<INVALID SOURCE LOCATION>>>>>";
   }
-  
-  const llvm::MemoryBuffer *Buf
-    = SLoc.getFile().getContentCache()->getBuffer(Diag, *this, SourceLocation(), 
-                                                  &MyInvalid);
+
+  llvm::MemoryBuffer *Buf = SLoc.getFile().getContentCache()->getBuffer(
+      Diag, *this, SourceLocation(), &MyInvalid);
   if (Invalid)
     *Invalid = MyInvalid;
 
@@ -1117,9 +1114,8 @@ const char *SourceManager::getCharacterData(SourceLocation SL,
     
     return "<<<<INVALID BUFFER>>>>";
   }
-  const llvm::MemoryBuffer *Buffer
-    = Entry.getFile().getContentCache()
-                  ->getBuffer(Diag, *this, SourceLocation(), &CharDataInvalid);
+  llvm::MemoryBuffer *Buffer = Entry.getFile().getContentCache()->getBuffer(
+      Diag, *this, SourceLocation(), &CharDataInvalid);
   if (Invalid)
     *Invalid = CharDataInvalid;
   return Buffer->getBufferStart() + (CharDataInvalid? 0 : LocInfo.second);
@@ -1131,7 +1127,7 @@ const char *SourceManager::getCharacterData(SourceLocation SL,
 unsigned SourceManager::getColumnNumber(FileID FID, unsigned FilePos,
                                         bool *Invalid) const {
   bool MyInvalid = false;
-  const llvm::MemoryBuffer *MemBuf = getBuffer(FID, &MyInvalid);
+  llvm::MemoryBuffer *MemBuf = getBuffer(FID, &MyInvalid);
   if (Invalid)
     *Invalid = MyInvalid;
 
@@ -1205,8 +1201,7 @@ static void ComputeLineNumbers(DiagnosticsEngine &Diag, ContentCache *FI,
                                llvm::BumpPtrAllocator &Alloc,
                                const SourceManager &SM, bool &Invalid) {
   // Note that calling 'getBuffer()' may lazily page in the file.
-  const MemoryBuffer *Buffer = FI->getBuffer(Diag, SM, SourceLocation(),
-                                             &Invalid);
+  MemoryBuffer *Buffer = FI->getBuffer(Diag, SM, SourceLocation(), &Invalid);
   if (Invalid)
     return;
 
@@ -1763,7 +1758,7 @@ SourceLocation SourceManager::translateLineCol(FileID FID,
     return FileLoc.getLocWithOffset(Size);
   }
 
-  const llvm::MemoryBuffer *Buffer = Content->getBuffer(Diag, *this);
+  llvm::MemoryBuffer *Buffer = Content->getBuffer(Diag, *this);
   unsigned FilePos = Content->SourceLineCache[Line - 1];
   const char *Buf = Buffer->getBufferStart() + FilePos;
   unsigned BufLength = Buffer->getBufferSize() - FilePos;
diff --git a/lib/CodeGen/CodeGenAction.cpp b/lib/CodeGen/CodeGenAction.cpp
index 18fa0fad92..3342aa12c8 100644
--- a/lib/CodeGen/CodeGenAction.cpp
+++ b/lib/CodeGen/CodeGenAction.cpp
@@ -641,14 +641,12 @@ void CodeGenAction::ExecuteAction() {
 
     bool Invalid;
     SourceManager &SM = CI.getSourceManager();
-    const llvm::MemoryBuffer *MainFile = SM.getBuffer(SM.getMainFileID(),
-                                                      &Invalid);
+    llvm::MemoryBuffer *MainFile = SM.getBuffer(SM.getMainFileID(), &Invalid);
     if (Invalid)
       return;
 
     llvm::SMDiagnostic Err;
-    TheModule.reset(
-        ParseIR(const_cast<MemoryBuffer *>(MainFile), Err, *VMContext));
+    TheModule.reset(ParseIR(MainFile, Err, *VMContext));
     if (!TheModule) {
       // Translate from the diagnostic info to the SourceManager location.
       SourceLocation Loc = SM.translateFileLineCol(
diff --git a/lib/Frontend/CompilerInstance.cpp b/lib/Frontend/CompilerInstance.cpp
index 03a2c229d0..b5efb14dc2 100644
--- a/lib/Frontend/CompilerInstance.cpp
+++ b/lib/Frontend/CompilerInstance.cpp
@@ -884,7 +884,7 @@ static void compileModuleImpl(CompilerInstance &ImportingInstance,
     FrontendOpts.Inputs.push_back(
         FrontendInputFile("__inferred_module.map", IK));
 
-    const llvm::MemoryBuffer *ModuleMapBuffer =
+    llvm::MemoryBuffer *ModuleMapBuffer =
         llvm::MemoryBuffer::getMemBuffer(InferredModuleMapContent);
     ModuleMapFile = Instance.getFileManager().getVirtualFile(
         "__inferred_module.map", InferredModuleMapContent.size(), 0);
diff --git a/lib/Index/SimpleFormatContext.h b/lib/Index/SimpleFormatContext.h
index 147323a710..de1665f3b6 100644
--- a/lib/Index/SimpleFormatContext.h
+++ b/lib/Index/SimpleFormatContext.h
@@ -47,8 +47,7 @@ public:
   ~SimpleFormatContext() { }
 
   FileID createInMemoryFile(StringRef Name, StringRef Content) {
-    const llvm::MemoryBuffer *Source =
-        llvm::MemoryBuffer::getMemBuffer(Content);
+    llvm::MemoryBuffer *Source = llvm::MemoryBuffer::getMemBuffer(Content);
     const FileEntry *Entry =
         Files.getVirtualFile(Name, Source->getBufferSize(), 0);
     Sources.overrideFileContents(Entry, Source);
diff --git a/tools/clang-format/ClangFormat.cpp b/tools/clang-format/ClangFormat.cpp
index e0239499af..575ac7a93d 100644
--- a/tools/clang-format/ClangFormat.cpp
+++ b/tools/clang-format/ClangFormat.cpp
@@ -103,7 +103,7 @@ static cl::list<std::string> FileNames(cl::Positional, cl::desc("[<file> ...]"),
 namespace clang {
 namespace format {
 
-static FileID createInMemoryFile(StringRef FileName, const MemoryBuffer *Source,
+static FileID createInMemoryFile(StringRef FileName, MemoryBuffer *Source,
                                  SourceManager &Sources, FileManager &Files) {
   const FileEntry *Entry = Files.getVirtualFile(FileName == "-" ? "<stdin>" :
                                                     FileName,
diff --git a/tools/libclang/CIndex.cpp b/tools/libclang/CIndex.cpp
index fdd6334bac..8683ae62b0 100644
--- a/tools/libclang/CIndex.cpp
+++ b/tools/libclang/CIndex.cpp
@@ -2787,8 +2787,8 @@ static void clang_parseTranslationUnit_Impl(void *UserData) {
 
   for (unsigned I = 0; I != num_unsaved_files; ++I) {
     StringRef Data(unsaved_files[I].Contents, unsaved_files[I].Length);
-    const llvm::MemoryBuffer *Buffer
-      = llvm::MemoryBuffer::getMemBufferCopy(Data, unsaved_files[I].Filename);
+    llvm::MemoryBuffer *Buffer =
+        llvm::MemoryBuffer::getMemBufferCopy(Data, unsaved_files[I].Filename);
     RemappedFiles->push_back(std::make_pair(unsaved_files[I].Filename,
                                             Buffer));
   }
@@ -3073,8 +3073,8 @@ static void clang_reparseTranslationUnit_Impl(void *UserData) {
   
   for (unsigned I = 0; I != num_unsaved_files; ++I) {
     StringRef Data(unsaved_files[I].Contents, unsaved_files[I].Length);
-    const llvm::MemoryBuffer *Buffer
-      = llvm::MemoryBuffer::getMemBufferCopy(Data, unsaved_files[I].Filename);
+    llvm::MemoryBuffer *Buffer =
+        llvm::MemoryBuffer::getMemBufferCopy(Data, unsaved_files[I].Filename);
     RemappedFiles->push_back(std::make_pair(unsaved_files[I].Filename,
                                             Buffer));
   }
diff --git a/tools/libclang/CIndexCodeCompletion.cpp b/tools/libclang/CIndexCodeCompletion.cpp
index edc8368ca3..9dd2dfec7a 100644
--- a/tools/libclang/CIndexCodeCompletion.cpp
+++ b/tools/libclang/CIndexCodeCompletion.cpp
@@ -695,8 +695,8 @@ void clang_codeCompleteAt_Impl(void *UserData) {
   SmallVector<ASTUnit::RemappedFile, 4> RemappedFiles;
   for (unsigned I = 0; I != num_unsaved_files; ++I) {
     StringRef Data(unsaved_files[I].Contents, unsaved_files[I].Length);
-    const llvm::MemoryBuffer *Buffer
-      = llvm::MemoryBuffer::getMemBufferCopy(Data, unsaved_files[I].Filename);
+    llvm::MemoryBuffer *Buffer =
+        llvm::MemoryBuffer::getMemBufferCopy(Data, unsaved_files[I].Filename);
     RemappedFiles.push_back(std::make_pair(unsaved_files[I].Filename,
                                            Buffer));
   }
diff --git a/tools/libclang/Indexing.cpp b/tools/libclang/Indexing.cpp
index 6bb995ae5a..24ab7b206c 100644
--- a/tools/libclang/Indexing.cpp
+++ b/tools/libclang/Indexing.cpp
@@ -592,8 +592,8 @@ static void clang_indexSourceFile_Impl(void *UserData) {
 
   for (unsigned I = 0; I != num_unsaved_files; ++I) {
     StringRef Data(unsaved_files[I].Contents, unsaved_files[I].Length);
-    const llvm::MemoryBuffer *Buffer
-      = llvm::MemoryBuffer::getMemBufferCopy(Data, unsaved_files[I].Filename);
+    llvm::MemoryBuffer *Buffer =
+        llvm::MemoryBuffer::getMemBufferCopy(Data, unsaved_files[I].Filename);
     CInvok->getPreprocessorOpts().addRemappedFile(unsaved_files[I].Filename, Buffer);
     BufOwner->Buffers.push_back(Buffer);
   }
diff --git a/unittests/Tooling/RewriterTestContext.h b/unittests/Tooling/RewriterTestContext.h
index ed29f8c04d..fe108ad308 100644
--- a/unittests/Tooling/RewriterTestContext.h
+++ b/unittests/Tooling/RewriterTestContext.h
@@ -48,8 +48,7 @@ class RewriterTestContext {
   ~RewriterTestContext() {}
 
   FileID createInMemoryFile(StringRef Name, StringRef Content) {
-    const llvm::MemoryBuffer *Source =
-      llvm::MemoryBuffer::getMemBuffer(Content);
+    llvm::MemoryBuffer *Source = llvm::MemoryBuffer::getMemBuffer(Content);
     const FileEntry *Entry =
       Files.getVirtualFile(Name, Source->getBufferSize(), 0);
     Sources.overrideFileContents(Entry, Source);