[llvm-readobj] Display section names for STT_SECTION symbols.
Summary:
This patch will obtain the section name for symbols that refer to a section. Prior to this patch the Name field for STT_SECTIONs was blank, now it is populated.
Before:
```
Symbol table '.symtab' contains 6 entries:
Num: Value Size Type Bind Vis Ndx Name
0:
0000000000000000 0 NOTYPE LOCAL DEFAULT UND
1:
0000000000000000 0 SECTION LOCAL DEFAULT 1
2:
0000000000000000 0 SECTION LOCAL DEFAULT 3
3:
0000000000000000 0 SECTION LOCAL DEFAULT 4
4:
0000000000000000 0 NOTYPE GLOBAL DEFAULT UND _GLOBAL_OFFSET_TABLE_
5:
0000000000000000 0 TLS GLOBAL DEFAULT UND sym
```
With this patch:
```
Symbol table '.symtab' contains 6 entries:
Num: Value Size Type Bind Vis Ndx Name
0:
0000000000000000 0 NOTYPE LOCAL DEFAULT UND
1:
0000000000000000 0 SECTION LOCAL DEFAULT 1 .text
2:
0000000000000000 0 SECTION LOCAL DEFAULT 3 .data
3:
0000000000000000 0 SECTION LOCAL DEFAULT 4 .bss
4:
0000000000000000 0 NOTYPE GLOBAL DEFAULT UND _GLOBAL_OFFSET_TABLE_
5:
0000000000000000 0 TLS GLOBAL DEFAULT UND sym
```
This fixes PR40788
Reviewers: jhenderson, rupprecht, espindola
Reviewed By: rupprecht
Subscribers: emaste, javed.absar, arichardson, MaskRay, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D58796
llvm-svn: 355207