Make computeSymbolSizes never fail.

On ELF that was already the case since getting the size of a symbol
never fails.

On MachO and COFF we could fail trying to get the section of a symbol. But
we don't really need the section, just the section number to know if two
symbols are in the same section or not.

llvm-svn: 240580
diff --git a/llvm/lib/Object/COFFObjectFile.cpp b/llvm/lib/Object/COFFObjectFile.cpp
index 07f9d6e..797ee1a 100644
--- a/llvm/lib/Object/COFFObjectFile.cpp
+++ b/llvm/lib/Object/COFFObjectFile.cpp
@@ -258,6 +258,11 @@
   return std::error_code();
 }
 
+unsigned COFFObjectFile::getSymbolSectionID(SymbolRef Sym) const {
+  COFFSymbolRef Symb = getCOFFSymbol(Sym.getRawDataRefImpl());
+  return Symb.getSectionNumber();
+}
+
 void COFFObjectFile::moveSectionNext(DataRefImpl &Ref) const {
   const coff_section *Sec = toSec(Ref);
   Sec += 1;
@@ -311,6 +316,13 @@
   return (Sec->Characteristics & BssFlags) == BssFlags;
 }
 
+unsigned COFFObjectFile::getSectionID(SectionRef Sec) const {
+  uintptr_t Offset =
+      uintptr_t(Sec.getRawDataRefImpl().p) - uintptr_t(SectionTable);
+  assert((Offset % sizeof(coff_section)) == 0);
+  return (Offset / sizeof(coff_section)) + 1;
+}
+
 bool COFFObjectFile::isSectionVirtual(DataRefImpl Ref) const {
   const coff_section *Sec = toSec(Ref);
   // In COFF, a virtual section won't have any in-file