[llvm-readobj/elf] - Don't use unwrapOrError when reporting errors about SHT_DYNAMIC sections.

[grimar]

Summary

This changes messages reported to stop using dynamic section names (use describe() instead).
This allows to avoid unwrapOrError and improves diagnostics.

[jhenderson]

LGTM.

llvm/test/tools/llvm-readobj/ELF/dynamic-not-in-pt-dynamic.test

 ## Show that llvm-readobj/llvm-readelf tools sometimes can dump the
 ## dynamic table when it is not in a PT_DYNAMIC segment.
 
 ## Case 1: The dynamic table found using the dynamic program header is corrupted
 ##         (<size of data> % <size of dynamic entry> != 0). So the table is taken
 ##         from the section header.
 
 # RUN: yaml2obj --docnum=1 %s -o %t1.o
 # RUN: llvm-readobj --dynamic-table %t1.o 2>&1 \
 # RUN:   | FileCheck -DFILE=%t1.o --check-prefixes=WARNING1,LLVM1 %s
 # RUN: llvm-readelf --dynamic-table %t1.o 2>&1 \
 # RUN:   | FileCheck -DFILE=%t1.o --check-prefixes=WARNING1,GNU1 %s
 
-# WARNING1: warning: '[[FILE]]': The SHT_DYNAMIC section '.dynamic' is not contained within the PT_DYNAMIC segment
+# WARNING1: warning: '[[FILE]]': SHT_DYNAMIC section with index 1 is not contained within the PT_DYNAMIC segment
 # WARNING1: warning: '[[FILE]]': invalid PT_DYNAMIC size (0x1){{$}}
 # WARNING1: warning: '[[FILE]]': SHT_DYNAMIC section header and PT_DYNAMIC program header disagree about the location of the dynamic table
 # WARNING1: warning: '[[FILE]]': PT_DYNAMIC dynamic table is invalid: SHT_DYNAMIC will be used
 
 # LLVM1:      DynamicSection [ (2 entries)
 # LLVM1-NEXT:   Tag                Type     Name/Value
 # LLVM1-NEXT:   0x0000000000000018 BIND_NOW 0x1
 # LLVM1-NEXT:   0x0000000000000000 NULL     0x0

 ##         table found using the section header table.
 
 # RUN: yaml2obj --docnum=2 %s -o %t2.o
 # RUN: llvm-readobj --dynamic-table %t2.o 2>&1 \
 # RUN:   | FileCheck -DFILE=%t2.o --check-prefixes=WARNING2,LLVM2 %s
 # RUN: llvm-readelf --dynamic-table %t2.o 2>&1 \
 # RUN:   | FileCheck -DFILE=%t2.o --check-prefixes=WARNING2,GNU2 %s
 
-# WARNING2: warning: '[[FILE]]': The SHT_DYNAMIC section '.dynamic' is not contained within the PT_DYNAMIC segment
+# WARNING2: warning: '[[FILE]]': SHT_DYNAMIC section with index 1 is not contained within the PT_DYNAMIC segment
 # WARNING2: warning: '[[FILE]]': SHT_DYNAMIC section header and PT_DYNAMIC program header disagree about the location of the dynamic table
 
 # LLVM2:      DynamicSection [ (1 entries)
 # LLVM2-NEXT:   Tag                Type     Name/Value
 # LLVM2-NEXT:   0x0000000000000000 NULL     0x0
 # LLVM2-NEXT: ]
 
 # GNU2:      Dynamic section at offset 0x{{.*}} contains 1 entries:

llvm/test/tools/llvm-readobj/ELF/non-dynamic-in-pt-dynamic.test

 ## Show that llvm-readobj/llvm-readelf tools can dump the .dynamic section which
 ## is not alone in PT_DYNAMIC segment.
 
 ## In the first case .text is placed before .dynamic.
 ## We check that we warn about this case.
 
 # RUN: yaml2obj --docnum=1 %s -o %t1.o
 # RUN: llvm-readobj --dynamic-table %t1.o 2>&1 \
 # RUN:   | FileCheck %s --DFILE=%t1.o --check-prefixes=WARNING,LLVM
 # RUN: llvm-readelf --dynamic-table %t1.o 2>&1 \
 # RUN:   | FileCheck %s --DFILE=%t1.o --check-prefixes=WARNING,GNU
 
-# WARNING: warning: '[[FILE]]': The SHT_DYNAMIC section '.dynamic' is not at the start of PT_DYNAMIC segment
+# WARNING: warning: '[[FILE]]': SHT_DYNAMIC section with index 2 is not at the start of PT_DYNAMIC segment
 # WARNING: warning: '[[FILE]]': invalid PT_DYNAMIC size (0x21){{$}}
 # WARNING: warning: '[[FILE]]': SHT_DYNAMIC section header and PT_DYNAMIC program header disagree about the location of the dynamic table
 # WARNING: warning: '[[FILE]]': PT_DYNAMIC dynamic table is invalid: SHT_DYNAMIC will be used
 
 # LLVM:      DynamicSection [ (2 entries)
 # LLVM-NEXT:   Tag                Type     Name/Value
 # LLVM-NEXT:   0x0000000000000018 BIND_NOW 0x1
 # LLVM-NEXT:   0x0000000000000000 NULL     0x0

llvm/tools/llvm-readobj/ELFDumper.cpp

reportUniqueWarning(createError(
         Twine::utohexstr(DynamicPhdr->p_filesz) +
         ") exceeds the size of the file (0x" +
         Twine::utohexstr(ObjF->getMemoryBufferRef().getBufferSize()) + ")"));
     // Don't use the broken dynamic header.
     DynamicPhdr = nullptr;
   }
 
   if (DynamicPhdr && DynamicSec) {
-    StringRef Name =
-        unwrapOrError(ObjF->getFileName(), Obj->getSectionName(DynamicSec));
     if (DynamicSec->sh_addr + DynamicSec->sh_size >
             DynamicPhdr->p_vaddr + DynamicPhdr->p_memsz ||
         DynamicSec->sh_addr < DynamicPhdr->p_vaddr)
-      reportWarning(createError("The SHT_DYNAMIC section '" + Name +
-                                "' is not contained within the "
+      reportWarning(createError(describe(*DynamicSec) +
+                                " is not contained within the "
                                 "PT_DYNAMIC segment"),
                     ObjF->getFileName());
 
     if (DynamicSec->sh_addr != DynamicPhdr->p_vaddr)
-      reportWarning(createError("The SHT_DYNAMIC section '" + Name +
-                                "' is not at the start of "
+      reportWarning(createError(describe(*DynamicSec) +
+                                " is not at the start of "
                                 "PT_DYNAMIC segment"),
                     ObjF->getFileName());
   }
 
   return std::make_pair(DynamicPhdr, DynamicSec);
 }
 
 template <typename ELFT>