From 1051909df1a2dfc9e3b4b27d15b36b3019c21463 Mon Sep 17 00:00:00 2001
From: Kevin Enderby <enderby@apple.com>
Date: Mon, 27 Jun 2016 21:39:39 +0000
Subject: Change all but the last ErrorOr<...> use for MachOUniversalBinary to
 Expected<...> to allow a good error message to be produced.
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I added the one test case that the object file tools could produce an error
message.  The other two errors can’t be triggered if the input file is passed
through sys::fs::identify_magic().  But the malformedError("bad magic number")
does get triggered by the logic in llvm-dsymutil when dealing with a normal
Mach-O file.  The other "File too small ..." error would take a logic error
currently to produce and is not tested for.

llvm-svn: 273946
---
 llvm/lib/Object/MachOUniversal.cpp | 33 ++++++++++++++++++++++-----------
 1 file changed, 22 insertions(+), 11 deletions(-)

(limited to 'llvm/lib/Object/MachOUniversal.cpp')

diff --git a/llvm/lib/Object/MachOUniversal.cpp b/llvm/lib/Object/MachOUniversal.cpp
index b3b0c251c10..e6880587cde 100644
--- a/llvm/lib/Object/MachOUniversal.cpp
+++ b/llvm/lib/Object/MachOUniversal.cpp
@@ -22,6 +22,13 @@
 using namespace llvm;
 using namespace object;
 
+static Error
+malformedError(Twine Msg) {
+  std::string StringMsg = "truncated or malformed fat file (" + Msg.str() + ")";
+  return make_error<GenericBinaryError>(std::move(StringMsg),
+                                        object_error::parse_failed);
+}
+
 template<typename T>
 static T getUniversalBinaryStruct(const char *Ptr) {
   T Res;
@@ -92,22 +99,24 @@ MachOUniversalBinary::ObjectForArch::getAsArchive() const {
 
 void MachOUniversalBinary::anchor() { }
 
-ErrorOr<std::unique_ptr<MachOUniversalBinary>>
+Expected<std::unique_ptr<MachOUniversalBinary>>
 MachOUniversalBinary::create(MemoryBufferRef Source) {
-  std::error_code EC;
+  Error Err;
   std::unique_ptr<MachOUniversalBinary> Ret(
-      new MachOUniversalBinary(Source, EC));
-  if (EC)
-    return EC;
+      new MachOUniversalBinary(Source, Err));
+  if (Err)
+    return std::move(Err);
   return std::move(Ret);
 }
 
-MachOUniversalBinary::MachOUniversalBinary(MemoryBufferRef Source,
-                                           std::error_code &ec)
+MachOUniversalBinary::MachOUniversalBinary(MemoryBufferRef Source, Error &Err)
     : Binary(Binary::ID_MachOUniversalBinary, Source), Magic(0),
       NumberOfObjects(0) {
+  ErrorAsOutParameter ErrAsOutParam(Err);
   if (Data.getBufferSize() < sizeof(MachO::fat_header)) {
-    ec = object_error::invalid_file_type;
+    Err = make_error<GenericBinaryError>("File too small to be a Mach-O "
+                                         "universal file",
+                                         object_error::invalid_file_type);
     return;
   }
   // Check for magic value and sufficient header size.
@@ -121,14 +130,16 @@ MachOUniversalBinary::MachOUniversalBinary(MemoryBufferRef Source,
   else if (Magic == MachO::FAT_MAGIC_64)
     MinSize += sizeof(MachO::fat_arch_64) * NumberOfObjects;
   else {
-    ec = object_error::parse_failed;
+    Err = malformedError("bad magic number");
     return;
   }
   if (Buf.size() < MinSize) {
-    ec = object_error::parse_failed;
+    Err = malformedError("fat_arch" +
+                         Twine(Magic == MachO::FAT_MAGIC ? "" : "_64") +
+                         " structs would extend past the end of the file");
     return;
   }
-  ec = std::error_code();
+  Err = Error::success();
 }
 
 Expected<std::unique_ptr<MachOObjectFile>>
-- 
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