[DebugInfo] Fix crash caused by unhandled error.

[Higuoxing]

Summary

This patch helps fix LLVM crash caused by unhandled error.

[Higuoxing]

Update.

llvm/lib/DebugInfo/GSYM/ObjectFileTransformer.cpp

llvm::Error ObjectFileTransformer::convert(const object::ObjectFile &Obj,
 
   // Read build ID.
   Gsym.setUUID(getUUID(Obj));
 
   // Parse the symbol table.
   size_t NumBefore = Gsym.getNumFunctionInfos();
   for (const object::SymbolRef &Sym : Obj.symbols()) {
     Expected<SymbolRef::Type> SymType = Sym.getType();
+    if (!SymType) {
+      logAllUnhandledErrors(SymType.takeError(), Log,
+                            "ObjectFileTransformer: ");
+      continue;
+    }
     const uint64_t Addr = Sym.getValue();
-    if (!SymType || SymType.get() != SymbolRef::Type::ST_Function ||
+    if (SymType.get() != SymbolRef::Type::ST_Function ||
         !Gsym.IsValidTextAddress(Addr) || Gsym.hasFunctionInfoForAddress(Addr))
       continue;
     // Function size for MachO files will be 0
     constexpr bool NoCopy = false;
     const uint64_t size = IsELF ? ELFSymbolRef(Sym).getSize() : 0;
     Expected<StringRef> Name = Sym.getName();
     if (!Name) {
       logAllUnhandledErrors(Name.takeError(), Log, "ObjectFileTransformer: ");

llvm/test/DebugInfo/gsym-invalid-section-offset.yaml

+## This test ensures that LLVM will not crash when converting a Mach-O object
+## file with a malformed symbol whose n_sect points to an invalid offset.
+
+# RUN: llvm-gsymutil --convert %s -o %t.macho 2>&1 |
+# RUN:   FileCheck %s
+
+# CHECK: ObjectFileTransformer: truncated or malformed object (bad section index: 3 for symbol at index 0)
+
+--- !mach-o
+FileHeader:
+  magic:       0xFEEDFACF
+  cputype:     0x01000007
+  cpusubtype:  0x00000003
+  filetype:    0x0000000A
+  ncmds:       1
+  sizeofcmds:  100
+  flags:       0x00000000
+  reserved:    0x00000000
+LoadCommands:
+  - cmd:       LC_SYMTAB
+    cmdsize:   24
+    symoff:    4096
+    nsyms:     1
+    stroff:    4144
+    strsize:   6
+LinkEditData:
+  NameList:
+    - n_strx:  2    # _foo
+      n_type:  0x0e
+      n_sect:  3    # Points to an invalid offset.
+      n_desc:  0
+      n_value: 1234
+  StringTable:
+    - ''
+    - ''
+    - _foo