[llvm-readobj/elf] - Change the behavior of handing DT_SONAME.

[grimar]

Summary

The current situation/behavior is:

1. llvm-readelf doesn't need a string that is specified by DT_SONAME.
2. llvm-readobj/elf always tries to read it, even when there is no DT_SONAME tag.
3. Because of that both tools reports a warning for many our test cases.

This patch delays getting a SOName string and changes the behavior (llvm-readobj) to
only report a warning when there is a DT_SONAME and a string cab't be read.
Warning is not reported for llvm-readelf, as it never tries to dump it.

[MaskRay]

llvm-readelf doesn't need a string that is specified by DT_SONAME.
llvm-readobj/elf always tries to read it, even when there is no DT_SONAME tag.

Agree. An absent DT_SONAME is like a value of 0.

Because of that both tools reports a warning for many our test cases.

I am confused by this point. Is it about the behavior when .dynstr is absent? .dynstr should always exist (st_size>=1).

[grimar]

In D89384#2333673, @MaskRay wrote:

Because of that both tools reports a warning for many our test cases.

I am confused by this point. Is it about the behavior when .dynstr is absent?

Yes.

.dynstr should always exist (st_size>=1).

It is about cases when we need to have the .dynamic section for whatever reason, but don't have the DT_SONAME tag.
Currently we don't recognize that it is absent and trying to read a string from the .dynstr.
In those tests we often don't need to have the .dynstr, so it doesn't exist.

[jhenderson]

Looks good, thanks.

llvm/test/tools/llvm-readobj/ELF/dynamic-tags.test

496–497

Maybe worth a blank line between these two to highlight that the LoadName printing is not part of the dynamic section printing.

llvm/test/tools/llvm-readobj/ELF/dynamic-malformed.test

 # BAD-STRING-LLVM-NEXT:   0x000000000000000E SONAME    Library soname: [<?>]
 # BAD-STRING-LLVM-NEXT: warning: '[[FILE]]': string table at offset 0xb0: unable to read the string at 0xb7: it goes past the end of the table (0xb1)
 # BAD-STRING-LLVM-NEXT:   0x000000000000000F RPATH     Library rpath: [<?>]
 # BAD-STRING-LLVM-NEXT: warning: '[[FILE]]': string table at offset 0xb0: unable to read the string at 0xb8: it goes past the end of the table (0xb1)
 # BAD-STRING-LLVM-NEXT:   0x000000000000001D RUNPATH   Library runpath: [<?>]
 # BAD-STRING-LLVM-NEXT:   0x0000000000000000 NULL      0x0
 # BAD-STRING-LLVM-NEXT: ]
 
-# BAD-STRING-GNU:      warning: '[[FILE]]': string table at offset 0xb0: unable to read the string at 0xb6: it goes past the end of the table (0xb1)
-# BAD-STRING-GNU-NEXT: Dynamic section at offset 0xb1 contains 10 entries:
+# BAD-STRING-GNU:      Dynamic section at offset 0xb1 contains 10 entries:
 # BAD-STRING-GNU-NEXT:   Tag                Type        Name/Value
 # BAD-STRING-GNU-NEXT:   0x0000000000000005 (STRTAB)    0x1000
 # BAD-STRING-GNU-NEXT:   0x000000000000000a (STRSZ)     1 (bytes)
 # BAD-STRING-GNU-NEXT: warning: '[[FILE]]': string table at offset 0xb0: unable to read the string at 0xb2: it goes past the end of the table (0xb1)
 # BAD-STRING-GNU-NEXT:   0x0000000000000001 (NEEDED)    Shared library: [<?>]
 # BAD-STRING-GNU-NEXT: warning: '[[FILE]]': string table at offset 0xb0: unable to read the string at 0xb3: it goes past the end of the table (0xb1)
 # BAD-STRING-GNU-NEXT:   0x000000007fffffff (FILTER)    Filter library: [<?>]
 # BAD-STRING-GNU-NEXT: warning: '[[FILE]]': string table at offset 0xb0: unable to read the string at 0xb4: it goes past the end of the table (0xb1)
 # BAD-STRING-GNU-NEXT:   0x000000007ffffffd (AUXILIARY) Auxiliary library: [<?>]
 # BAD-STRING-GNU-NEXT: warning: '[[FILE]]': string table at offset 0xb0: unable to read the string at 0xb5: it goes past the end of the table (0xb1)
 # BAD-STRING-GNU-NEXT:   0x000000007ffffffe (USED)      Not needed object: [<?>]
-## Note: there is no "string table at offset 0xb6..." warning here, because it was printed earlier.
+# BAD-STRING-GNU-NEXT: warning: '[[FILE]]': string table at offset 0xb0: unable to read the string at 0xb6: it goes past the end of the table (0xb1)
 # BAD-STRING-GNU-NEXT:   0x000000000000000e (SONAME)    Library soname: [<?>]
 # BAD-STRING-GNU-NEXT: warning: '[[FILE]]': string table at offset 0xb0: unable to read the string at 0xb7: it goes past the end of the table (0xb1)
 # BAD-STRING-GNU-NEXT:   0x000000000000000f (RPATH)     Library rpath: [<?>]
 # BAD-STRING-GNU-NEXT: warning: '[[FILE]]': string table at offset 0xb0: unable to read the string at 0xb8: it goes past the end of the table (0xb1)
 # BAD-STRING-GNU-NEXT:   0x000000000000001d (RUNPATH)   Library runpath: [<?>]
 # BAD-STRING-GNU-NEXT:   0x0000000000000000 (NULL)      0x0
 
 --- !ELF
- Type: PT_DYNAMIC
     VAddr: 0x1010
     Sections:
       - Section: .dynamic
 
 ## Test handling of DT_STRTAB pointing outside the file's address space.
 # RUN: yaml2obj %s --docnum=4 -o %t.bad-strtab
 
 # RUN: llvm-readobj --dynamic-table %t.bad-strtab 2>&1 >/dev/null | \
-# RUN:   FileCheck -DFILE=%t.bad-strtab %s --check-prefix BAD-STRTAB-ERR
+# RUN:   FileCheck -DFILE=%t.bad-strtab %s --implicit-check-not=warning: --check-prefix=BAD-STRTAB-ERR
 # RUN: llvm-readelf --dynamic-table %t.bad-strtab 2>&1 >/dev/null | \
-# RUN:   FileCheck -DFILE=%t.bad-strtab %s --check-prefix BAD-STRTAB-ERR
-# BAD-STRTAB-ERR: warning: '[[FILE]]': Unable to parse DT_STRTAB: virtual address is not in any segment: 0x2000000
-# BAD-STRTAB-ERR: warning: '[[FILE]]': string table was not found
+# RUN:   FileCheck -DFILE=%t.bad-strtab %s --implicit-check-not=warning: --check-prefix=BAD-STRTAB-ERR
+# BAD-STRTAB-ERR:    warning: '[[FILE]]': Unable to parse DT_STRTAB: virtual address is not in any segment: 0x2000000
+# BAD-STRTAB-ERR:    warning: '[[FILE]]': string table was not found
+# BAD-STRTAB-ERR-NOT:{{.}}
 
 # RUN: llvm-readobj --dynamic-table --needed-libs %t.bad-strtab 2>&1 | \
-# RUN:   FileCheck -DFILE=%t.bad-strtab %s --check-prefixes=BAD-STRTAB-ERR,BAD-STRTAB,BAD-STRTAB-LLVM
+# RUN:   FileCheck -DFILE=%t.bad-strtab %s --check-prefixes=BAD-STRTAB-ERR2,BAD-STRTAB,BAD-STRTAB-LLVM
 # RUN: llvm-readelf --dynamic-table --needed-libs %t.bad-strtab 2>&1 | \
-# RUN:   FileCheck -DFILE=%t.bad-strtab %s --check-prefixes=BAD-STRTAB-ERR,BAD-STRTAB,BAD-STRTAB-GNU
+# RUN:   FileCheck -DFILE=%t.bad-strtab %s --check-prefixes=BAD-STRTAB-ERR2,BAD-STRTAB,BAD-STRTAB-GNU
 
-# BAD-STRTAB-LLVM: LoadName: <?>
-# BAD-STRTAB-LLVM: 0x0000000000000001  NEEDED   Shared library: [<?>]
-# BAD-STRTAB-GNU:  0x0000000000000001 (NEEDED)  Shared library: [<?>]
-# BAD-STRTAB:      NeededLibraries [
-# BAD-STRTAB:        <?>
-# BAD-STRTAB:      ]
+#      BAD-STRTAB-ERR2: warning: '[[FILE]]': Unable to parse DT_STRTAB: virtual address is not in any segment: 0x2000000
+#      BAD-STRTAB-LLVM: LoadName: <Not found>
+#           BAD-STRTAB: warning: '[[FILE]]': string table was not found
+# BAD-STRTAB-LLVM-NEXT: 0x0000000000000001  NEEDED   Shared library: [<?>]
+#  BAD-STRTAB-GNU-NEXT: 0x0000000000000001 (NEEDED)  Shared library: [<?>]
+#           BAD-STRTAB: NeededLibraries [
+#           BAD-STRTAB:   <?>
+#           BAD-STRTAB: ]
 
 --- !ELF
 FileHeader:
   Class: ELFCLASS64
   Data:  ELFDATA2LSB
   Type:  ET_EXEC
 Sections:
   - Name:    .dynamic
Sections:
       - Section: .dynamic
 
 ## Check how we handle cases when the dynamic string table is not null-terminated.
 
 ## Case A: the value of the DT_STRSZ tag is equal to the size of
 ##         the not null-terminated dynamic string table.
 # RUN: yaml2obj %s -DSTRSZ=7 --docnum=6 -o %t6
 # RUN: llvm-readobj --dynamic-table %t6 2>&1 | \
-# RUN:   FileCheck %s -DFILE=%t6 --implicit-check-not=warning: --check-prefixes=NOT-TERMINATED,NOT-TERMINATED-GREQ
+# RUN:   FileCheck %s -DFILE=%t6 --implicit-check-not=warning: \
+# RUN:     --check-prefixes=NOT-TERMINATED,NOT-TERMINATED-LLVM,NOT-TERMINATED-GREQ
 # RUN: llvm-readelf --dynamic-table %t6 2>&1 | \
-# RUN:   FileCheck %s -DFILE=%t6 --implicit-check-not=warning: --check-prefixes=NOT-TERMINATED,NOT-TERMINATED-GREQ
+# RUN:   FileCheck %s -DFILE=%t6 --implicit-check-not=warning: \
+# RUN:     --check-prefixes=NOT-TERMINATED,NOT-TERMINATED-GNU,NOT-TERMINATED-GREQ
 
 ## Case B: the value of the DT_STRSZ tag is less than the size of
 ##         the not null-terminated dynamic string table.
 # RUN: yaml2obj %s -DSTRSZ=6 --docnum=6 -o %t7
 # RUN: llvm-readobj --dynamic-table %t7 2>&1 | \
-# RUN:   FileCheck %s -DFILE=%t7 --implicit-check-not=warning: --check-prefixes=NOT-TERMINATED,NOT-TERMINATED-LESS
+# RUN:   FileCheck %s -DFILE=%t7 --implicit-check-not=warning: \
+# RUN:     --check-prefixes=NOT-TERMINATED,NOT-TERMINATED-LLVM,NOT-TERMINATED-LESS
 # RUN: llvm-readelf --dynamic-table %t7 2>&1 | \
-# RUN:   FileCheck %s -DFILE=%t7 --implicit-check-not=warning: --check-prefixes=NOT-TERMINATED,NOT-TERMINATED-LESS
+# RUN:   FileCheck %s -DFILE=%t7 --implicit-check-not=warning: \
+# RUN:     --check-prefixes=NOT-TERMINATED,NOT-TERMINATED-GNU,NOT-TERMINATED-LESS
 
 ## Case C: the value of the DT_STRSZ tag is one byte larger than the size of
 ##         the not null-terminated dynamic string table.
 # RUN: yaml2obj %s -DSTRSZ=8 --docnum=6 -o %t8
 # RUN: llvm-readobj --dynamic-table %t8 2>&1 | \
-# RUN:   FileCheck %s -DFILE=%t8 --implicit-check-not=warning: --check-prefixes=NOT-TERMINATED,NOT-TERMINATED-GREQ
+# RUN:   FileCheck %s -DFILE=%t8 --implicit-check-not=warning: \
+# RUN:     --check-prefixes=NOT-TERMINATED,NOT-TERMINATED-LLVM,NOT-TERMINATED-GREQ
 # RUN: llvm-readelf --dynamic-table %t8 2>&1 | \
-# RUN:   FileCheck %s -DFILE=%t8 --implicit-check-not=warning: --check-prefixes=NOT-TERMINATED,NOT-TERMINATED-GREQ
+# RUN:   FileCheck %s -DFILE=%t8 --implicit-check-not=warning: \
+# RUN:     --check-prefixes=NOT-TERMINATED,NOT-TERMINATED-GNU,NOT-TERMINATED-GREQ
 
-# NOT-TERMINATED:      warning: '[[FILE]]': string table at offset 0xb0: unable to read the string at 0xb4: the string table is not null-terminated
+# NOT-TERMINATED-LLVM: warning: '[[FILE]]': string table at offset 0xb0: unable to read the string at 0xb4: the string table is not null-terminated
 # NOT-TERMINATED:      warning: '[[FILE]]': string table at offset 0xb0: unable to read the string at 0xb0: the string table is not null-terminated
 # NOT-TERMINATED-NEXT: {{[(]?}}NEEDED{{[)]?}}    Shared library: [<?>]
 # NOT-TERMINATED-NEXT: warning: '[[FILE]]': string table at offset 0xb0: unable to read the string at 0xb1: the string table is not null-terminated
 # NOT-TERMINATED-NEXT: {{[(]?}}FILTER{{[)]?}}    Filter library: [<?>]
 # NOT-TERMINATED-NEXT: warning: '[[FILE]]': string table at offset 0xb0: unable to read the string at 0xb2: the string table is not null-terminated
 # NOT-TERMINATED-NEXT: {{[(]?}}AUXILIARY{{[)]?}} Auxiliary library: [<?>]
 # NOT-TERMINATED-NEXT: warning: '[[FILE]]': string table at offset 0xb0: unable to read the string at 0xb3: the string table is not null-terminated
 # NOT-TERMINATED-NEXT: {{[(]?}}USED{{[)]?}}      Not needed object: [<?>]
+# NOT-TERMINATED-GNU-NEXT:  warning: '[[FILE]]': string table at offset 0xb0: unable to read the string at 0xb4: the string table is not null-terminated
 # NOT-TERMINATED-NEXT: {{[(]?}}SONAME{{[)]?}}    Library soname: [<?>]
 # NOT-TERMINATED-NEXT: warning: '[[FILE]]': string table at offset 0xb0: unable to read the string at 0xb5: the string table is not null-terminated
 # NOT-TERMINATED-NEXT: {{[(]?}}RPATH{{[)]?}}     Library rpath: [<?>]
 # NOT-TERMINATED-GREQ-NEXT: warning: '[[FILE]]': string table at offset 0xb0: unable to read the string at 0xb6: the string table is not null-terminated
 # NOT-TERMINATED-LESS-NEXT: warning: '[[FILE]]': string table at offset 0xb0: unable to read the string at 0xb6: it goes past the end of the table (0xb6)
 # NOT-TERMINATED-NEXT: {{[(]?}}RUNPATH{{[)]?}}   Library runpath: [<?>]
 # NOT-TERMINATED-NEXT: {{[(]?}}NULL{{[)]?}}      0x0
 

llvm/test/tools/llvm-readobj/ELF/dynamic-tags.test

 # PHENTSIZE-WARN-NEXT: warning: '[[FILE]]': Unable to parse DT_SYMTAB: invalid e_phentsize: 1
 # PHENTSIZE-WARN-NEXT: warning: '[[FILE]]': Unable to parse DT_RELA: invalid e_phentsize: 1
 # PHENTSIZE-WARN-NEXT: warning: '[[FILE]]': DT_SYMENT value of 0x987 is not the size of a symbol (0x18)
 # PHENTSIZE-WARN-NEXT: warning: '[[FILE]]': Unable to parse DT_REL: invalid e_phentsize: 1
 # PHENTSIZE-WARN-NEXT: warning: '[[FILE]]': Unable to parse DT_JMPREL: invalid e_phentsize: 1
 # PHENTSIZE-WARN-NEXT: warning: '[[FILE]]': Unable to parse DT_RELR: invalid e_phentsize: 1
 # PHENTSIZE-WARN-NEXT: warning: '[[FILE]]': Unable to parse DT_ANDROID_RELR: invalid e_phentsize: 1
 # PHENTSIZE-WARN-NEXT: warning: '[[FILE]]': Unable to parse DT_GNU_HASH: invalid e_phentsize: 1
-# PHENTSIZE-WARN-NEXT: warning: '[[FILE]]': string table was not found
 
+# PHENTSIZE-LLVM:      warning: '[[FILE]]': string table was not found
+# PHENTSIZE-LLVM-NEXT: LoadName: <?>
 # PHENTSIZE-LLVM:      DynamicSection [ (61 entries)
 # PHENTSIZE-LLVM-NEXT:   Tag                Type                 Name/Value
 # PHENTSIZE-LLVM-NEXT:   0x0000000000000001 NEEDED               Shared library: [<?>]
 # PHENTSIZE-LLVM-NEXT:   0x0000000000000002 PLTRELSZ             16 (bytes)
 # PHENTSIZE-LLVM-NEXT:   0x0000000000000003 PLTGOT               0x1000
 # PHENTSIZE-LLVM-NEXT:   0x0000000000000004 HASH                 0x1000
 # PHENTSIZE-LLVM-NEXT:   0x0000000000000005 STRTAB               0x1000
 # PHENTSIZE-LLVM-NEXT:   0x0000000000000006 SYMTAB               0x1000
 # PHENTSIZE-LLVM-NEXT:   0x0000000000000007 RELA                 0x1000

 # PHENTSIZE-LLVM-NEXT:   0x0000000012345678 <unknown:>0x12345678 0x8765432187654321
 # PHENTSIZE-LLVM-NEXT:   0x000000006ABCDEF0 <unknown:>0x6abcdef0 0x9988776655443322
 # PHENTSIZE-LLVM-NEXT:   0x0000000076543210 <unknown:>0x76543210 0x5555666677778888
 # PHENTSIZE-LLVM-NEXT:   0x0000000000000000 NULL                 0x0
 # PHENTSIZE-LLVM-NEXT: ]
 
 # PHENTSIZE-GNU:      Dynamic section at offset 0xc0 contains 61 entries:
 # PHENTSIZE-GNU-NEXT:   Tag                Type                   Name/Value
+# PHENTSIZE-GNU-NEXT: warning: '[[FILE]]': string table was not found
 # PHENTSIZE-GNU-NEXT:   0x0000000000000001 (NEEDED)               Shared library: [<?>]
 # PHENTSIZE-GNU-NEXT:   0x0000000000000002 (PLTRELSZ)             16 (bytes)
 # PHENTSIZE-GNU-NEXT:   0x0000000000000003 (PLTGOT)               0x1000
 # PHENTSIZE-GNU-NEXT:   0x0000000000000004 (HASH)                 0x1000
 # PHENTSIZE-GNU-NEXT:   0x0000000000000005 (STRTAB)               0x1000
 # PHENTSIZE-GNU-NEXT:   0x0000000000000006 (SYMTAB)               0x1000
 # PHENTSIZE-GNU-NEXT:   0x0000000000000007 (RELA)                 0x1000
 # PHENTSIZE-GNU-NEXT:   0x0000000000000008 (RELASZ)               16 (bytes)

llvm/test/tools/llvm-readobj/ELF/hash-table.test

 
 # RUN: yaml2obj --docnum=1 -DMACHINE=EM_ALPHA %s -o %t.alpha
 # RUN: llvm-readobj --hash-table %t.alpha 2>&1 | FileCheck %s -DFILE=%t.alpha --check-prefixes=WARN-HASH -DNAME="EM_ALPHA"
 # RUN: llvm-readelf --hash-table %t.alpha 2>&1 | FileCheck %s -DFILE=%t.alpha --check-prefixes=WARN-HASH -DNAME="EM_ALPHA"
 
 ## We don't report warnings about the unsupported hash table on EM_S390 and EM_ALPHA platforms
 ## when --hash-table is not requested.
 
-# RUN: llvm-readobj %t.s390 2>&1 | FileCheck %s -DFILE=%t.s390 --implicit-check-not="warning:"  --check-prefix=NOWARN
-# RUN: llvm-readelf %t.s390 2>&1 | FileCheck %s -DFILE=%t.s390 --implicit-check-not="warning:"  --check-prefix=NOWARN
-# RUN: llvm-readobj %t.alpha 2>&1 | FileCheck %s -DFILE=%t.alpha --implicit-check-not="warning:" --check-prefix=NOWARN
-# RUN: llvm-readelf %t.alpha 2>&1 | FileCheck %s -DFILE=%t.alpha --implicit-check-not="warning:" --check-prefix=NOWARN
-
-# NOWARN: warning: '[[FILE]]': string table was not found
+# RUN: llvm-readobj %t.s390 2>&1 | FileCheck %s -DFILE=%t.s390 --allow-empty --implicit-check-not="warning:"
+# RUN: llvm-readelf %t.s390 2>&1 | FileCheck %s -DFILE=%t.s390 --allow-empty --implicit-check-not="warning:"
+# RUN: llvm-readobj %t.alpha 2>&1 | FileCheck %s -DFILE=%t.alpha --allow-empty --implicit-check-not="warning:"
+# RUN: llvm-readelf %t.alpha 2>&1 | FileCheck %s -DFILE=%t.alpha --allow-empty --implicit-check-not="warning:"
 
 ## Check we can dump the SHT_HASH section even when an object
 ## does not have the section header table.
 
 # RUN: yaml2obj --docnum=2 -DNOHEADERS=true %s -o %t.noshdr
 # RUN: llvm-readobj --hash-table %t.noshdr 2>&1 | \
 # RUN:   FileCheck %s -DFILE=%t.noshdr --check-prefix=NOSHDR --implicit-check-not=warning:
 # RUN: llvm-readelf --hash-table %t.noshdr 2>&1 | \
 # RUN:   FileCheck %s -DFILE=%t.noshdr --check-prefix=NOSHDR --implicit-check-not=warning:
 
-# NOSHDR: warning: '[[FILE]]': string table was not found
-
 # NOSHDR:      HashTable {
 # NOSHDR-NEXT:   Num Buckets: 1
 # NOSHDR-NEXT:   Num Chains: 1
 # NOSHDR-NEXT:   Buckets: [0]
 # NOSHDR-NEXT:   Chains: [1]
 # NOSHDR-NEXT: }
 
 --- !ELF

 ## Document we need the DT_HASH dynamic tag to locate the hash table.
 
 # RUN: yaml2obj --docnum=2 -DDYNTAG=DT_NULL %s -o %t.no.dyntag
 # RUN: llvm-readobj --hash-table %t.no.dyntag 2>&1 | \
 # RUN:   FileCheck %s -DFILE=%t.no.dyntag --check-prefix=NODYNTAG --implicit-check-not=warning:
 # RUN: llvm-readelf --hash-table %t.no.dyntag 2>&1 | \
 # RUN:   FileCheck %s -DFILE=%t.no.dyntag --check-prefix=NODYNTAG --implicit-check-not=warning:
 
-# NODYNTAG: warning: '[[FILE]]': string table was not found
-
 # NODYNTAG:      HashTable {
 # NODYNTAG-NEXT: }
 
 ## Each SHT_HASH section starts with two 32-bit fields: nbucket and nchain.
 ## Check we report an error when a DT_HASH value points to data that has size less than 8 bytes.
 
 # RUN: yaml2obj --docnum=3 %s -o %t4.o
 # RUN: llvm-readelf --hash-table %t4.o 2>&1 | FileCheck %s --check-prefix=ERR1 -DFILE=%t4.o

llvm/test/tools/llvm-readobj/ELF/needed-libs.test

 
 ## Check what we print when the dynamic string table is empty.
 # RUN: yaml2obj %s --docnum=2 -o %t2
 # RUN: llvm-readobj --needed-libs %t2 2>&1 | \
 # RUN:   FileCheck %s -DFILE=%t2 --implicit-check-not=warning: --check-prefixes=EMPTY-DYNSTR,EMPTY-DYNSTR-LLVM
 # RUN: llvm-readelf --needed-libs %t2 2>&1 | \
 # RUN:   FileCheck %s -DFILE=%t2 --implicit-check-not=warning: --check-prefix=EMPTY-DYNSTR
 
-# EMPTY-DYNSTR:      warning: '[[FILE]]': string table at offset 0x78: unable to read the string at 0x78: it goes past the end of the table (0x78)
-# EMPTY-DYNSTR-LLVM: LoadName: <?>
 # EMPTY-DYNSTR:      NeededLibraries [
 # EMPTY-DYNSTR-NEXT: warning: '[[FILE]]': string table at offset 0x78: unable to read the string at 0x79: it goes past the end of the table (0x78)
 # EMPTY-DYNSTR-NEXT: warning: '[[FILE]]': string table at offset 0x78: unable to read the string at 0x7a: it goes past the end of the table (0x78)
 # EMPTY-DYNSTR-NEXT:   <?>
 # EMPTY-DYNSTR-NEXT:   <?>
 # EMPTY-DYNSTR-NEXT: ]
 
 --- !ELF

llvm/tools/llvm-readobj/ELFDumper.cpp

private:
   const ELFFile<ELFT> &Obj;
   DynRegionInfo DynRelRegion;
   DynRegionInfo DynRelaRegion;
   DynRegionInfo DynRelrRegion;
   DynRegionInfo DynPLTRelRegion;
   Optional<DynRegionInfo> DynSymRegion;
   DynRegionInfo DynamicTable;
   StringRef DynamicStringTable;
-  StringRef SOName = "<Not found>";
   const Elf_Hash *HashTable = nullptr;
   const Elf_GnuHash *GnuHashTable = nullptr;
   const Elf_Shdr *DotSymtabSec = nullptr;
   const Elf_Shdr *DotDynsymSec = nullptr;
   const Elf_Shdr *DotCGProfileSec = nullptr;
   const Elf_Shdr *DotAddrsigSec = nullptr;
   ArrayRef<Elf_Word> ShndxTable;
+  Optional<uint64_t> SONameOffset;
 
   const Elf_Shdr *SymbolVersionSection = nullptr;   // .gnu.version
   const Elf_Shdr *SymbolVersionNeedSection = nullptr; // .gnu.version_r
   const Elf_Shdr *SymbolVersionDefSection = nullptr; // .gnu.version_d
 
   struct VersionEntry {
     std::string Name;
     bool IsVerDef;
if (!MappedAddrOrError) {
                       ": " + llvm::toString(MappedAddrOrError.takeError()));
 
       reportWarning(std::move(Err), ObjF.getFileName());
       return nullptr;
     }
     return MappedAddrOrError.get();
   };
 
-  uint64_t SONameOffset = 0;
   const char *StringTableBegin = nullptr;
   uint64_t StringTableSize = 0;
   Optional<DynRegionInfo> DynSymFromTable;
   for (const Elf_Dyn &Dyn : dynamic_table()) {
     switch (Dyn.d_tag) {
     case ELF::DT_HASH:
       HashTable = reinterpret_cast<const Elf_Hash *>(
           toMappedAddr(Dyn.getTag(), Dyn.getPtr()));
if (StringTableSize > FileSize - Offset)
       reportUniqueWarning(createError(
           "the dynamic string table at 0x" + Twine::utohexstr(Offset) +
           " goes past the end of the file (0x" + Twine::utohexstr(FileSize) +
           ") with DT_STRSZ = 0x" + Twine::utohexstr(StringTableSize)));
     else
       DynamicStringTable = StringRef(StringTableBegin, StringTableSize);
   }
 
-  SOName = getDynamicString(SONameOffset);
-
   const bool IsHashTableSupported = getHashTableEntSize() == 4;
   if (DynSymRegion) {
     // Often we find the information about the dynamic symbol table
     // location in the SHT_DYNSYM section header. However, the value in
     // DT_SYMTAB has priority, because it is used by dynamic loaders to
     // locate .dynsym at runtime. The location we find in the section header
     // and the location we find here should match.
     if (DynSymFromTable && DynSymFromTable->Addr != DynSymRegion->Addr)
reportUniqueWarning(
                     toString(Chains.takeError())));
     return;
   }
 
   W.printHexList("Values", *Chains);
 }
 
 template <typename ELFT> void ELFDumper<ELFT>::printLoadName() {
+  StringRef SOName = "<Not found>";
+  if (SONameOffset)
+    SOName = getDynamicString(*SONameOffset);
   W.printString("LoadName", SOName);
 }
 
 template <class ELFT> void ELFDumper<ELFT>::printArchSpecificInfo() {
   switch (Obj.getHeader().e_machine) {
   case EM_ARM:
   case EM_RISCV:
     printAttributes();