--- a/tools/clang/include/clang-c/Index.h
+++ a/tools/clang/include/clang-c/Index.h
@@ -404,6 +404,21 @@
                                     const char *file_name);
 
 /**
+ * \brief Retrieve the buffer associated with the given file.
+ *
+ * \param tu the translation unit
+ *
+ * \param file the file for which to retrieve the buffer.
+ *
+ * \param size [out] if non-NULL, will be set to the size of the buffer.
+ *
+ * \returns a pointer to the buffer in memory that holds the contents of
+ * \p file, or a NULL pointer when the file is not loaded.
+ */
+CINDEX_LINKAGE const char *clang_getFileContents(CXTranslationUnit tu,
+                                                 CXFile file, size_t *size);
+
+/**
  * \brief Returns non-zero if the \c file1 and \c file2 point to the same file,
  * or they are both NULL.
  */
--- a/tools/clang/tools/libclang/CIndex.cpp
+++ a/tools/clang/tools/libclang/CIndex.cpp
@@ -4162,6 +4162,27 @@
   return const_cast<FileEntry *>(FMgr.getFile(file_name));
 }
 
+const char *clang_getFileContents(CXTranslationUnit TU, CXFile file,
+                                  size_t *size) {
+  if (isNotUsableTU(TU)) {
+    LOG_BAD_TU(TU);
+    return nullptr;
+  }
+
+  const SourceManager &SM = cxtu::getASTUnit(TU)->getSourceManager();
+  FileID fid = SM.translateFile(static_cast<FileEntry *>(file));
+  bool Invalid = true;
+  llvm::MemoryBuffer *buf = SM.getBuffer(fid, &Invalid);
+  if (Invalid) {
+    if (size)
+      *size = 0;
+    return nullptr;
+  }
+  if (size)
+    *size = buf->getBufferSize();
+  return buf->getBufferStart();
+}
+
 unsigned clang_isFileMultipleIncludeGuarded(CXTranslationUnit TU,
                                             CXFile file) {
   if (isNotUsableTU(TU)) {
--- a/tools/clang/tools/libclang/libclang.exports
+++ b/tools/clang/tools/libclang/libclang.exports
@@ -216,6 +216,7 @@ clang_getExceptionSpecificationType
 clang_getFieldDeclBitWidth
 clang_getExpansionLocation
 clang_getFile
+clang_getFileContents
 clang_getFileLocation
 clang_getFileName
 clang_getFileTime