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, 10 insertions, 4 deletions

diff --git a/llvm/tools/dsymutil/MachODebugMapParser.cpp b/llvm/tools/dsymutil/MachODebugMapParser.cpp
index 29529942cb8..87577610752 100644
--- a/llvm/tools/dsymutil/MachODebugMapParser.cpp
+++ b/llvm/tools/dsymutil/MachODebugMapParser.cpp
@@ -402,9 +402,12 @@ void MachODebugMapParser::loadCurrentObjectFileSymbols(
 
   for (auto Sym : Obj.symbols()) {
     uint64_t Addr = Sym.getValue();
-    ErrorOr<StringRef> Name = Sym.getName();
-    if (!Name)
+    Expected<StringRef> Name = Sym.getName();
+    if (!Name) {
+      // TODO: Actually report errors helpfully.
+      consumeError(Name.takeError());
       continue;
+    }
     // The value of some categories of symbols isn't meaningful. For
     // example common symbols store their size in the value field, not
     // their address. Absolute symbols have a fixed address that can
@@ -457,9 +460,12 @@ void MachODebugMapParser::loadMainBinarySymbols(
     if (Section == MainBinary.section_end() || Section->isText())
       continue;
     uint64_t Addr = Sym.getValue();
-    ErrorOr<StringRef> NameOrErr = Sym.getName();
-    if (!NameOrErr)
+    Expected<StringRef> NameOrErr = Sym.getName();
+    if (!NameOrErr) {
+      // TODO: Actually report errors helpfully.
+      consumeError(NameOrErr.takeError());
       continue;
+    }
     StringRef Name = *NameOrErr;
     if (Name.size() == 0 || Name[0] == '\0')
       continue;