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, 8 insertions, 3 deletions

diff --git a/llvm/lib/Object/Object.cpp b/llvm/lib/Object/Object.cpp
index 4932f233f17..58d8fa08235 100644
--- a/llvm/lib/Object/Object.cpp
+++ b/llvm/lib/Object/Object.cpp
@@ -178,9 +178,14 @@ void LLVMMoveToNextRelocation(LLVMRelocationIteratorRef SI) {
 
 // SymbolRef accessors
 const char *LLVMGetSymbolName(LLVMSymbolIteratorRef SI) {
-  ErrorOr<StringRef> Ret = (*unwrap(SI))->getName();
-  if (std::error_code EC = Ret.getError())
-    report_fatal_error(EC.message());
+  Expected<StringRef> Ret = (*unwrap(SI))->getName();
+  if (!Ret) {
+    std::string Buf;
+    raw_string_ostream OS(Buf);
+    logAllUnhandledErrors(Ret.takeError(), OS, "");
+    OS.flush();
+    report_fatal_error(Buf);
+  }
   return Ret->data();
 }