[llvm-readobj] - Always print "Predecessors" for version definition sections.

This is a follow-up discussed in D70495 thread.

The current logic is unusual for llvm-readobj. It doesn't print predecessors
list when it is empty. This is not good for machine parsers.
D70495 had to add this condition during refactoring to reduce amount of changes,
in tests, because the original code also had a similar logic.

Now seems it is time to get rid of it. This patch does it.

Differential revision: https://reviews.llvm.org/D70717

lld/test/ELF/verdef-defaultver.s

@@ -84,6 +84,7 @@
 # DSO-NEXT:      Index: 1
 # DSO-NEXT:      Hash: 127830196
 # DSO-NEXT:      Name: shared
+# DSO-NEXT:      Predecessors: []
 # DSO-NEXT:    }
 # DSO-NEXT:    Definition {
 # DSO-NEXT:      Version: 1
@@ -92,6 +93,7 @@
 # DSO-NEXT:      Index: 2
 # DSO-NEXT:      Hash: 1425
 # DSO-NEXT:      Name: V1
+# DSO-NEXT:      Predecessors: []
 # DSO-NEXT:    }
 # DSO-NEXT:    Definition {
 # DSO-NEXT:      Version: 1
@@ -100,6 +102,7 @@
 # DSO-NEXT:      Index: 3
 # DSO-NEXT:      Hash: 1426
 # DSO-NEXT:      Name: V2
+# DSO-NEXT:      Predecessors: []
 # DSO-NEXT:    }
 # DSO-NEXT:  ]
 

lld/test/ELF/verdef-dependency.s

@@ -15,6 +15,7 @@
 # DSO-NEXT:     Index: 1
 # DSO-NEXT:     Hash: 127830196
 # DSO-NEXT:     Name: shared
+# DSO-NEXT:     Predecessors: []
 # DSO-NEXT:   }
 # DSO-NEXT:   Definition {
 # DSO-NEXT:     Version: 1
@@ -23,6 +24,7 @@
 # DSO-NEXT:     Index: 2
 # DSO-NEXT:     Hash: 98457184
 # DSO-NEXT:     Name: LIBSAMPLE_1.0
+# DSO-NEXT:     Predecessors: []
 # DSO-NEXT:   }
 # DSO-NEXT:   Definition {
 # DSO-NEXT:     Version: 1
@@ -31,6 +33,7 @@
 # DSO-NEXT:     Index: 3
 # DSO-NEXT:     Hash: 98456416
 # DSO-NEXT:     Name: LIBSAMPLE_2.0
+# DSO-NEXT:     Predecessors: []
 # DSO-NEXT:   }
 # DSO-NEXT:   Definition {
 # DSO-NEXT:     Version: 1
@@ -39,5 +42,6 @@
 # DSO-NEXT:     Index: 4
 # DSO-NEXT:     Hash: 98456672
 # DSO-NEXT:     Name: LIBSAMPLE_3.0
+# DSO-NEXT:     Predecessors: []
 # DSO-NEXT:   }
 # DSO-NEXT: ]

lld/test/ELF/verdef.s

@@ -33,6 +33,7 @@
 # DSO-NEXT:     Index: 1
 # DSO-NEXT:     Hash: 127830196
 # DSO-NEXT:     Name: shared
+# DSO-NEXT:     Predecessors: []
 # DSO-NEXT:   }
 # DSO-NEXT:   Definition {
 # DSO-NEXT:     Version: 1
@@ -41,6 +42,7 @@
 # DSO-NEXT:     Index: 2
 # DSO-NEXT:     Hash: 98457184
 # DSO-NEXT:     Name: LIBSAMPLE_1.0
+# DSO-NEXT:     Predecessors: []
 # DSO-NEXT:   }
 # DSO-NEXT:   Definition {
 # DSO-NEXT:     Version: 1
@@ -49,6 +51,7 @@
 # DSO-NEXT:     Index: 3
 # DSO-NEXT:     Hash: 98456416
 # DSO-NEXT:     Name: LIBSAMPLE_2.0
+# DSO-NEXT:     Predecessors: []
 # DSO-NEXT:   }
 # DSO-NEXT:   Definition {
 # DSO-NEXT:     Version: 1
@@ -57,6 +60,7 @@
 # DSO-NEXT:     Index: 4
 # DSO-NEXT:     Hash: 98456672
 # DSO-NEXT:     Name: LIBSAMPLE_3.0
+# DSO-NEXT:     Predecessors: []
 # DSO-NEXT:   }
 # DSO-NEXT: ]
 # DSO-NEXT: VersionRequirements [

llvm/test/tools/llvm-readobj/elf-versioninfo.test

@@ -148,6 +148,7 @@ DynamicSymbols:
 # LLVM-NEXT:     Index: 0
 # LLVM-NEXT:     Hash: 0
 # LLVM-NEXT:     Name: VERSION1
+# LLVM-NEXT:     Predecessors: []
 # LLVM-NEXT:   }
 # LLVM-NEXT:   Definition {
 # LLVM-NEXT:     Version: 1
@@ -157,6 +158,7 @@ DynamicSymbols:
 # LLVM-NEXT:     Index: 0
 # LLVM-NEXT:     Hash: 0
 # LLVM-NEXT:     Name: VERSION1
+# LLVM-NEXT:     Predecessors: []
 # LLVM-NEXT:   }
 # LLVM-NEXT:   Definition {
 # LLVM-NEXT:     Version: 1
@@ -166,6 +168,7 @@ DynamicSymbols:
 # LLVM-NEXT:     Index: 0
 # LLVM-NEXT:     Hash: 0
 # LLVM-NEXT:     Name: VERSION1
+# LLVM-NEXT:     Predecessors: []
 # LLVM-NEXT:   }
 # LLVM-NEXT:   Definition {
 # LLVM-NEXT:     Version: 1
@@ -175,6 +178,7 @@ DynamicSymbols:
 # LLVM-NEXT:     Index: 0
 # LLVM-NEXT:     Hash: 0
 # LLVM-NEXT:     Name: VERSION1
+# LLVM-NEXT:     Predecessors: []
 # LLVM-NEXT:   }
 # LLVM-NEXT:   Definition {
 # LLVM-NEXT:     Version: 1
@@ -186,6 +190,7 @@ DynamicSymbols:
 # LLVM-NEXT:     Index: 2
 # LLVM-NEXT:     Hash: 175630257
 # LLVM-NEXT:     Name: VERSION1
+# LLVM-NEXT:     Predecessors: []
 # LLVM-NEXT:   }
 # LLVM-NEXT:   Definition {
 # LLVM-NEXT:     Version: 1
@@ -436,6 +441,7 @@ DynamicSymbols:
 # PAST-STRTAB-END-LLVM-NEXT:     Index: 0
 # PAST-STRTAB-END-LLVM-NEXT:     Hash: 0
 # PAST-STRTAB-END-LLVM-NEXT:     Name: <invalid vda_name: 5>
+# PAST-STRTAB-END-LLVM-NEXT:     Predecessors: []
 # PAST-STRTAB-END-LLVM-NEXT:   }
 # PAST-STRTAB-END-LLVM-NEXT: ]
 

llvm/test/tools/yaml2obj/ELF/verdef-section.yaml

@@ -12,6 +12,7 @@
 # CHECK-NEXT:     Index: 1
 # CHECK-NEXT:     Hash: 170240160
 # CHECK-NEXT:     Name: dso.so.0
+# CHECK-NEXT:     Predecessors: []
 # CHECK-NEXT:   }
 # CHECK-NEXT:   Definition {
 # CHECK-NEXT:     Version: 1
@@ -21,6 +22,7 @@
 # CHECK-NEXT:     Index: 2
 # CHECK-NEXT:     Hash: 108387921
 # CHECK-NEXT:     Name: VERSION_1
+# CHECK-NEXT:     Predecessors: []
 # CHECK-NEXT:   }
 # CHECK-NEXT:   Definition {
 # CHECK-NEXT:     Version: 1

llvm/tools/llvm-readobj/ELFDumper.cpp

@@ -5826,9 +5826,6 @@ void LLVMStyle<ELFT>::printVersionDefinitionSection(const ELFFile<ELFT> *Obj,
     W.printNumber("Index", D.Ndx);
     W.printNumber("Hash", D.Hash);
     W.printString("Name", D.Name.c_str());
-
-    if (D.AuxV.empty())
-      continue;
     W.printList(
         "Predecessors", D.AuxV,
         [](raw_ostream &OS, const VerdAux &Aux) { OS << Aux.Name.c_str(); });