Be a bit more consistent about using ErrorOr when constructing Binary objects.

The constructors of classes deriving from Binary normally take an error_code
as an argument to the constructor. My original intent was to change them
to have a trivial constructor and move the initial parsing logic to a static
method returning an ErrorOr. I changed my mind because:

* A constructor with an error_code out parameter is extremely convenient from
  the implementation side. We can incrementally construct the object and give
  up when we find an error.
* It is very efficient when constructing on the stack or when there is no
  error. The only inefficient case is where heap allocating and an error is
  found (we have to free the memory).

The result is that this is a much smaller patch. It just standardizes the
create* helpers to return an ErrorOr.

Almost no functionality change: The only difference is that this found that
we were trying to read past the end of COFF import library but ignoring the
error.

llvm-svn: 199770

1 files changed, 11 insertions, 8 deletions

diff --git a/llvm/lib/Object/COFFObjectFile.cpp b/llvm/lib/Object/COFFObjectFile.cpp
index ec8989d5c67..a7b06885008 100644
--- a/llvm/lib/Object/COFFObjectFile.cpp
+++ b/llvm/lib/Object/COFFObjectFile.cpp
@@ -514,10 +514,12 @@ COFFObjectFile::COFFObjectFile(MemoryBuffer *Object, error_code &EC)
     CurPtr += COFFHeader->SizeOfOptionalHeader;
   }
 
-  if (!COFFHeader->isImportLibrary())
-    if ((EC = getObject(SectionTable, Data, base() + CurPtr,
-                        COFFHeader->NumberOfSections * sizeof(coff_section))))
-      return;
+  if (COFFHeader->isImportLibrary())
+    return;
+
+  if ((EC = getObject(SectionTable, Data, base() + CurPtr,
+                      COFFHeader->NumberOfSections * sizeof(coff_section))))
+    return;
 
   // Initialize the pointer to the symbol table.
   if (COFFHeader->PointerToSymbolTable != 0)
@@ -1013,9 +1015,10 @@ error_code ExportDirectoryEntryRef::getSymbolName(StringRef &Result) const {
   return object_error::success;
 }
 
-namespace llvm {
-ObjectFile *ObjectFile::createCOFFObjectFile(MemoryBuffer *Object) {
+ErrorOr<ObjectFile *> ObjectFile::createCOFFObjectFile(MemoryBuffer *Object) {
   error_code EC;
-  return new COFFObjectFile(Object, EC);
-}
+  OwningPtr<COFFObjectFile> Ret(new COFFObjectFile(Object, EC));
+  if (EC)
+    return EC;
+  return Ret.take();
 }