[yaml2obj] - Allow to use numeric sh_link (Link) value for sections.

That change allows using numeric values for Link field.
It is consistent with the code for another fields in this method.

llvm-svn: 339873

test/tools/yaml2obj/section-link.yaml

@@ -0,0 +1,25 @@
+# RUN: yaml2obj %s -o %t
+# RUN: llvm-readobj -sections %t | FileCheck %s
+
+# CHECK:      Name: .text
+# CHECK-NEXT: Type: SHT_PROGBITS
+# CHECK-NEXT: Flags [
+# CHECK-NEXT:   SHF_ALLOC
+# CHECK-NEXT:   SHF_EXECINSTR
+# CHECK-NEXT: ]
+# CHECK-NEXT: Address:
+# CHECK-NEXT: Offset:
+# CHECK-NEXT: Size:
+# CHECK-NEXT: Link: 12345
+
+--- !ELF
+FileHeader:
+  Class:           ELFCLASS64
+  Data:            ELFDATA2LSB
+  Type:            ET_REL
+  Machine:         EM_X86_64
+Sections:
+  - Name:            .text
+    Type:            SHT_PROGBITS
+    Flags:           [ SHF_ALLOC, SHF_EXECINSTR ]
+    Link:            12345

tools/yaml2obj/yaml2elf.cpp

@@ -245,7 +245,7 @@ bool ELFState<ELFT>::initSectionHeaders(std::vector<Elf_Shdr> &SHeaders,
 
     if (!Sec->Link.empty()) {
       unsigned Index;
-      if (SN2I.lookup(Sec->Link, Index)) {
+      if (SN2I.lookup(Sec->Link, Index) && !to_integer(Sec->Link, Index)) {
         WithColor::error() << "Unknown section referenced: '" << Sec->Link
                            << "' at YAML section '" << Sec->Name << "'.\n";
         return false;