[llvm/Object] - Convert SectionRef::getName() to return Expected<>

SectionRef::getName() returns std::error_code now.
Returning Expected<> instead has multiple benefits.

For example, it forces user to check the error returned.
Also Expected<> may keep a valuable string error message,
what is more useful than having a error code.
(Object\invalid.test was updated to show the new messages printed.)

This patch makes a change for all users to switch to Expected<> version.

Note: in a few places the error returned was ignored before my changes.
In such places I left them ignored. My intention was to convert the interface
used, and not to improve and/or the existent users in this patch.
(Though I think this is good idea for a follow-ups to revisit such places
and either remove consumeError calls or comment each of them to clarify why
it is OK to have them).

Differential revision: https://reviews.llvm.org/D66089

llvm-svn: 368812

1 files changed, 9 insertions, 6 deletions

diff --git a/llvm/lib/Object/MachOObjectFile.cpp b/llvm/lib/Object/MachOObjectFile.cpp
index 3bfbfe06944..179166ddbd3 100644
--- a/llvm/lib/Object/MachOObjectFile.cpp
+++ b/llvm/lib/Object/MachOObjectFile.cpp
@@ -1986,13 +1986,12 @@ Expected<SectionRef> MachOObjectFile::getSection(unsigned SectionIndex) const {
 }
 
 Expected<SectionRef> MachOObjectFile::getSection(StringRef SectionName) const {
-  StringRef SecName;
   for (const SectionRef &Section : sections()) {
-    if (std::error_code E = Section.getName(SecName))
-      return errorCodeToError(E);
-    if (SecName == SectionName) {
+    auto NameOrErr = Section.getName();
+    if (!NameOrErr)
+      return NameOrErr.takeError();
+    if (*NameOrErr == SectionName)
       return Section;
-    }
   }
   return errorCodeToError(object_error::parse_failed);
 }
@@ -3995,7 +3994,11 @@ BindRebaseSegInfo::BindRebaseSegInfo(const object::MachOObjectFile *Obj) {
   uint64_t CurSegAddress;
   for (const SectionRef &Section : Obj->sections()) {
     SectionInfo Info;
-    Section.getName(Info.SectionName);
+    Expected<StringRef> NameOrErr = Section.getName();
+    if (!NameOrErr)
+      consumeError(NameOrErr.takeError());
+    else
+      Info.SectionName = *NameOrErr;
     Info.Address = Section.getAddress();
     Info.Size = Section.getSize();
     Info.SegmentName =