Thread Expected<...> up from libObject’s getName() for symbols to allow llvm-objdump to produce a good error message.

Produce another specific error message for a malformed Mach-O file when a symbol’s
string index is past the end of the string table.  The existing test case in test/Object/macho-invalid.test
for macho-invalid-symbol-name-past-eof now reports the error with the message indicating
that a symbol at a specific index has a bad sting index and that bad string index value.
 
Again converting interfaces to Expected<> from ErrorOr<> does involve
touching a number of places. Where the existing code reported the error with a
string message or an error code it was converted to do the same.  There is some
code for this that could be factored into a routine but I would like to leave that for
the code owners post-commit to do as they want for handling an llvm::Error.  An
example of how this could be done is shown in the diff in
lib/ExecutionEngine/RuntimeDyld/RuntimeDyldImpl.h which had a Check() routine
already for std::error_code so I added one like it for llvm::Error .

Also there some were bugs in the existing code that did not deal with the
old ErrorOr<> return values.  So now with Expected<> since they must be
checked and the error handled, I added a TODO and a comment:
“// TODO: Actually report errors helpfully” and a call something like
consumeError(NameOrErr.takeError()) so the buggy code will not crash
since needed to deal with the Error.

Note there fixes needed to lld that goes along with this that I will commit right after this.
So expect lld not to built after this commit and before the next one.

llvm-svn: 266919

1 files changed, 5 insertions, 1 deletions

diff --git a/llvm/tools/llvm-readobj/Win64EHDumper.cpp b/llvm/tools/llvm-readobj/Win64EHDumper.cpp
index 2da5ae3200f..e6e8367f293 100644
--- a/llvm/tools/llvm-readobj/Win64EHDumper.cpp
+++ b/llvm/tools/llvm-readobj/Win64EHDumper.cpp
@@ -120,13 +120,17 @@ static std::string formatSymbol(const Dumper::Context &Ctx,
 
   SymbolRef Symbol;
   if (!Ctx.ResolveSymbol(Section, Offset, Symbol, Ctx.UserData)) {
-    if (ErrorOr<StringRef> Name = Symbol.getName()) {
+    Expected<StringRef> Name = Symbol.getName();
+    if (Name) {
       OS << *Name;
       if (Displacement > 0)
         OS << format(" +0x%X (0x%" PRIX64 ")", Displacement, Offset);
       else
         OS << format(" (0x%" PRIX64 ")", Offset);
       return OS.str();
+    } else {
+      // TODO: Actually report errors helpfully.
+      consumeError(Name.takeError());
     }
   }