[ThinLTO] Deduplicate function index loading into shared helper (NFC)

Add a shared helper routine to read the function index from a file
and create/return the function index object. Use it in llvm-link and
llvm-lto.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@253903 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/Object/FunctionIndexObjectFile.h

@@ -99,6 +99,13 @@ class FunctionIndexObjectFile : public SymbolicFile {
                                  StringRef FunctionName);
 };
 }
+
+/// Parse the function index out of an IR file and return the function
+/// index object if found, or nullptr if not.
+ErrorOr<std::unique_ptr<FunctionInfoIndex>>
+getFunctionIndexForFile(StringRef Path,
+                        DiagnosticHandlerFunction DiagnosticHandler,
+                        const Module *ExportingModule = nullptr);
 }
 
 #endif

lib/Object/FunctionIndexObjectFile.cpp

@@ -120,3 +120,26 @@ std::error_code FunctionIndexObjectFile::findFunctionSummaryInMemBuffer(
     return object_error::invalid_file_type;
   }
 }
+
+// Parse the function index out of an IR file and return the function
+// index object if found, or nullptr if not.
+ErrorOr<std::unique_ptr<FunctionInfoIndex>>
+llvm::getFunctionIndexForFile(StringRef Path,
+                              DiagnosticHandlerFunction DiagnosticHandler,
+                              const Module *ExportingModule) {
+  ErrorOr<std::unique_ptr<MemoryBuffer>> FileOrErr =
+      MemoryBuffer::getFileOrSTDIN(Path);
+  std::error_code EC = FileOrErr.getError();
+  if (EC)
+    return EC;
+  MemoryBufferRef BufferRef = (FileOrErr.get())->getMemBufferRef();
+  ErrorOr<std::unique_ptr<object::FunctionIndexObjectFile>> ObjOrErr =
+      object::FunctionIndexObjectFile::create(BufferRef, DiagnosticHandler,
+                                              ExportingModule);
+  EC = ObjOrErr.getError();
+  if (EC)
+    return EC;
+
+  object::FunctionIndexObjectFile &Obj = **ObjOrErr;
+  return Obj.takeIndex();
+}

tools/llvm-link/llvm-link.cpp

@@ -141,27 +141,6 @@ static void diagnosticHandler(const DiagnosticInfo &DI) {
   errs() << '\n';
 }
 
-/// Load a function index if requested by the -functionindex option.
-static ErrorOr<std::unique_ptr<FunctionInfoIndex>>
-loadIndex(const Module *ExportingModule = nullptr) {
-  assert(!FunctionIndex.empty());
-  ErrorOr<std::unique_ptr<MemoryBuffer>> FileOrErr =
-      MemoryBuffer::getFileOrSTDIN(FunctionIndex);
-  std::error_code EC = FileOrErr.getError();
-  if (EC)
-    return EC;
-  MemoryBufferRef BufferRef = (FileOrErr.get())->getMemBufferRef();
-  ErrorOr<std::unique_ptr<object::FunctionIndexObjectFile>> ObjOrErr =
-      object::FunctionIndexObjectFile::create(BufferRef, diagnosticHandler,
-                                              ExportingModule);
-  EC = ObjOrErr.getError();
-  if (EC)
-    return EC;
-
-  object::FunctionIndexObjectFile &Obj = **ObjOrErr;
-  return Obj.takeIndex();
-}
-
 /// Import any functions requested via the -import option.
 static bool importFunctions(const char *argv0, LLVMContext &Context,
                             Linker &L) {
@@ -208,7 +187,8 @@ static bool importFunctions(const char *argv0, LLVMContext &Context,
 
     std::unique_ptr<FunctionInfoIndex> Index;
     if (!FunctionIndex.empty()) {
-      ErrorOr<std::unique_ptr<FunctionInfoIndex>> IndexOrErr = loadIndex();
+      ErrorOr<std::unique_ptr<FunctionInfoIndex>> IndexOrErr =
+          llvm::getFunctionIndexForFile(FunctionIndex, diagnosticHandler);
       std::error_code EC = IndexOrErr.getError();
       if (EC) {
         errs() << EC.message() << '\n';
@@ -245,7 +225,8 @@ static bool linkFiles(const char *argv0, LLVMContext &Context, Linker &L,
     // local functions/variables as exported and promote if necessary.
     std::unique_ptr<FunctionInfoIndex> Index;
     if (!FunctionIndex.empty()) {
-      ErrorOr<std::unique_ptr<FunctionInfoIndex>> IndexOrErr = loadIndex(&*M);
+      ErrorOr<std::unique_ptr<FunctionInfoIndex>> IndexOrErr =
+          llvm::getFunctionIndexForFile(FunctionIndex, diagnosticHandler, &*M);
       std::error_code EC = IndexOrErr.getError();
       if (EC) {
         errs() << EC.message() << '\n';

tools/llvm-lto/llvm-lto.cpp

@@ -190,32 +190,6 @@ static int listSymbols(StringRef Command, const TargetOptions &Options) {
   return 0;
 }
 
-/// Parse the function index out of an IR file and return the function
-/// index object if found, or nullptr if not.
-static ErrorOr<std::unique_ptr<FunctionInfoIndex>>
-getFunctionIndexForFile(StringRef Path,
-                        DiagnosticHandlerFunction DiagnosticHandler) {
-  std::unique_ptr<MemoryBuffer> Buffer;
-  ErrorOr<std::unique_ptr<MemoryBuffer>> BufferOrErr =
-      MemoryBuffer::getFile(Path);
-  if (std::error_code EC = BufferOrErr.getError())
-    return EC;
-  Buffer = std::move(BufferOrErr.get());
-
-  // Don't bother trying to build an index if there is no summary information
-  // in this bitcode file.
-  if (!object::FunctionIndexObjectFile::hasFunctionSummaryInMemBuffer(
-          Buffer->getMemBufferRef(), DiagnosticHandler))
-    return std::unique_ptr<FunctionInfoIndex>(nullptr);
-
-  ErrorOr<std::unique_ptr<object::FunctionIndexObjectFile>> ObjOrErr =
-      object::FunctionIndexObjectFile::create(Buffer->getMemBufferRef(),
-                                              DiagnosticHandler);
-  if (std::error_code EC = ObjOrErr.getError())
-    return EC;
-  return (*ObjOrErr)->takeIndex();
-}
-
 /// Create a combined index file from the input IR files and write it.
 ///
 /// This is meant to enable testing of ThinLTO combined index generation,
@@ -225,7 +199,7 @@ static int createCombinedFunctionIndex(StringRef Command) {
   uint64_t NextModuleId = 0;
   for (auto &Filename : InputFilenames) {
     ErrorOr<std::unique_ptr<FunctionInfoIndex>> IndexOrErr =
-        getFunctionIndexForFile(Filename, diagnosticHandler);
+        llvm::getFunctionIndexForFile(Filename, diagnosticHandler);
     if (std::error_code EC = IndexOrErr.getError()) {
       std::string Error = EC.message();
       errs() << Command << ": error loading file '" << Filename