[llvm-readobj/llvm-readelf] - Add checks for GNU-style to "all.test" test case.

[grimar]

Summary

We do not check the GNU-style output when -all is given.
This patch does that.

[grimar]

• Removed 2 missed unused tags from the YAML description.

[jhenderson]

test/tools/llvm-readobj/all.test

27–28 ↗

(On Diff #223202)

These two appear to be missing from the LLVM list above?

33–34 ↗

(On Diff #223202)

These two are also missing from the LLVM list.

49 ↗

(On Diff #223202)

I take it the version stuff is needed to make GNU mode print anything?

63 ↗

(On Diff #223202)

Do we need group information to print a header?

75–76 ↗

(On Diff #223202)

Can we just get away with the DT_NULL tag, or is DT_HASH required for the hash histogram behaviour?

86–90 ↗

(On Diff #223202)

Same comments as earlier. Can these be empty?

100 ↗

(On Diff #223202)

This could probably just be an arbitrary note, and much simpler.

[grimar]

test/tools/llvm-readobj/all.test

27–28 ↗

(On Diff #223202)

Yes. LLVM output seems to be inconsistent, incomplete and ugly sometimes. I'd review and refine it separatelly.

33–34 ↗

(On Diff #223202)

The same.

49 ↗

(On Diff #223202)

Yep, GNU style prints nothing if there is no version section.
See: https://github.com/llvm-mirror/llvm/blob/master/tools/llvm-readobj/ELFDumper.cpp#L3785

63 ↗

(On Diff #223202)

Yes.
Logic is:

1. Collect all group sections: https://github.com/llvm-mirror/llvm/blob/master/tools/llvm-readobj/ELFDumper.cpp#L2842
2. Dump them (header is printed on this step): https://github.com/llvm-mirror/llvm/blob/master/tools/llvm-readobj/ELFDumper.cpp#L2886

75–76 ↗

(On Diff #223202)

is DT_HASH required for the hash histogram behaviour?

Yes, we need it to get the DT_HASH content:
https://github.com/llvm-mirror/llvm/blob/master/tools/llvm-readobj/ELFDumper.cpp#L1712

86–90 ↗

(On Diff #223202)

No. We need to have something valid here, otherwise any
error triggered will fail the dumping.
(e.g. https://github.com/llvm-mirror/llvm/blob/master/tools/llvm-readobj/DwarfCFIEHPrinter.h#L127).

100 ↗

(On Diff #223202)

Probably. But it is already short enough and I do not want to spend time on optimising it until we have a way to describe
it with YAML. Having a raw content is anyways not optimal. What do you think?

[jhenderson]

test/tools/llvm-readobj/all.test

63 ↗

(On Diff #223202)

I see. Could you just check the "There are no section groups in the file" message instead? (https://github.com/llvm-mirror/llvm/blob/master/tools/llvm-readobj/ELFDumper.cpp#L2911)

I think that would be sufficient for this test case.

86–90 ↗

(On Diff #223202)

You don't actually need the .eh_frame_hdr at all, looking at the code, I think, just the .eh_frame section. That said, this appears to be different from GNU readelf.

For reference, GNU readelf prints "There are no unwind sections in this file" if there are no .eh_frame_hdr sections even if there is a .eh_frame section (not looked to see what happens if there is a PT_GNU_EH_FRAME program header).

100 ↗

(On Diff #223202)

Time to implement SHT_NOTE sections in yaml2obj :)

But happy for that to be later.

[grimar]

• Addressed review comments.

test/tools/llvm-readobj/all.test

63 ↗

(On Diff #223202)

Done.

86–90 ↗

(On Diff #223202)

I am a bit confused.

Imagine we have the code and invocations below:

"1.s":

.section foo,"ax",@progbits
.cfi_startproc
 nop
.cfi_endproc

as 1.s -o 1.o
ld.bfd 1.o -o with_hdr --eh-frame-hdr
ld.bfd 1.o -o wo_hdr

For both of them I do not see neither .eh_frame_hdr nor .eh_frame section dumped with -a.
I see ".eh_frame" dumped when I add -wf though (but still no .eh_frame_hdr).
e.g.:

umb@ubuntu:~/tests/81$ readelf -v
GNU readelf (GNU Binutils for Ubuntu) 2.31.1
Copyright (C) 2018 Free Software Foundation, Inc.

umb@ubuntu:~/tests/81$ readelf -a with_hdr
ELF Header:
  Magic:   7f 45 4c 46 02 01 01 00 00 00 00 00 00 00 00 00 
  Class:                             ELF64
  Data:                              2's complement, little endian
  Version:                           1 (current)
  OS/ABI:                            UNIX - System V
  ABI Version:                       0
  Type:                              EXEC (Executable file)
  Machine:                           Advanced Micro Devices X86-64
  Version:                           0x1
  Entry point address:               0x401000
  Start of program headers:          64 (bytes into file)
  Start of section headers:          8584 (bytes into file)
  Flags:                             0x0
  Size of this header:               64 (bytes)
  Size of program headers:           56 (bytes)
  Number of program headers:         3
  Size of section headers:           64 (bytes)
  Number of section headers:         7
  Section header string table index: 6

Section Headers:
  [Nr] Name              Type             Address           Offset
       Size              EntSize          Flags  Link  Info  Align
  [ 0]                   NULL             0000000000000000  00000000
       0000000000000000  0000000000000000           0     0     0
  [ 1] foo               PROGBITS         0000000000401000  00001000
       0000000000000001  0000000000000000  AX       0     0     1
  [ 2] .eh_frame_hdr     PROGBITS         0000000000402000  00002000
       0000000000000014  0000000000000000   A       0     0     4
  [ 3] .eh_frame         PROGBITS         0000000000402018  00002018
       000000000000002c  0000000000000000   A       0     0     8
  [ 4] .symtab           SYMTAB           0000000000000000  00002048
       00000000000000d8  0000000000000018           5     5     8
  [ 5] .strtab           STRTAB           0000000000000000  00002120
       000000000000002c  0000000000000000           0     0     1
  [ 6] .shstrtab         STRTAB           0000000000000000  0000214c
       0000000000000037  0000000000000000           0     0     1
Key to Flags:
  W (write), A (alloc), X (execute), M (merge), S (strings), I (info),
  L (link order), O (extra OS processing required), G (group), T (TLS),
  C (compressed), x (unknown), o (OS specific), E (exclude),
  l (large), p (processor specific)

There are no section groups in this file.

Program Headers:
  Type           Offset             VirtAddr           PhysAddr
                 FileSiz            MemSiz              Flags  Align
  LOAD           0x0000000000001000 0x0000000000401000 0x0000000000401000
                 0x0000000000000001 0x0000000000000001  R E    0x1000
  LOAD           0x0000000000002000 0x0000000000402000 0x0000000000402000
                 0x0000000000000044 0x0000000000000044  R      0x1000
  GNU_EH_FRAME   0x0000000000002000 0x0000000000402000 0x0000000000402000
                 0x0000000000000014 0x0000000000000014  R      0x4

 Section to Segment mapping:
  Segment Sections...
   00     foo 
   01     .eh_frame_hdr .eh_frame 
   02     .eh_frame_hdr 

There is no dynamic section in this file.

There are no relocations in this file.

The decoding of unwind sections for machine type Advanced Micro Devices X86-64 is not currently supported.

Symbol table '.symtab' contains 9 entries:
   Num:    Value          Size Type    Bind   Vis      Ndx Name
     0: 0000000000000000     0 NOTYPE  LOCAL  DEFAULT  UND 
     1: 0000000000401000     0 SECTION LOCAL  DEFAULT    1 
     2: 0000000000402000     0 SECTION LOCAL  DEFAULT    2 
     3: 0000000000402018     0 SECTION LOCAL  DEFAULT    3 
     4: 0000000000402000     0 NOTYPE  LOCAL  DEFAULT    2 __GNU_EH_FRAME_HDR
     5: 0000000000000000     0 NOTYPE  GLOBAL DEFAULT  UND _start
     6: 0000000000404000     0 NOTYPE  GLOBAL DEFAULT    3 __bss_start
     7: 0000000000404000     0 NOTYPE  GLOBAL DEFAULT    3 _edata
     8: 0000000000404000     0 NOTYPE  GLOBAL DEFAULT    3 _end

No version information found in this file.

umb@ubuntu:~/tests/81$ readelf -a with_hdr -wf
ELF Header:
  Magic:   7f 45 4c 46 02 01 01 00 00 00 00 00 00 00 00 00 
  Class:                             ELF64
  Data:                              2's complement, little endian
  Version:                           1 (current)
  OS/ABI:                            UNIX - System V
  ABI Version:                       0
  Type:                              EXEC (Executable file)
  Machine:                           Advanced Micro Devices X86-64
  Version:                           0x1
  Entry point address:               0x401000
  Start of program headers:          64 (bytes into file)
  Start of section headers:          8584 (bytes into file)
  Flags:                             0x0
  Size of this header:               64 (bytes)
  Size of program headers:           56 (bytes)
  Number of program headers:         3
  Size of section headers:           64 (bytes)
  Number of section headers:         7
  Section header string table index: 6

Section Headers:
  [Nr] Name              Type             Address           Offset
       Size              EntSize          Flags  Link  Info  Align
  [ 0]                   NULL             0000000000000000  00000000
       0000000000000000  0000000000000000           0     0     0
  [ 1] foo               PROGBITS         0000000000401000  00001000
       0000000000000001  0000000000000000  AX       0     0     1
  [ 2] .eh_frame_hdr     PROGBITS         0000000000402000  00002000
       0000000000000014  0000000000000000   A       0     0     4
  [ 3] .eh_frame         PROGBITS         0000000000402018  00002018
       000000000000002c  0000000000000000   A       0     0     8
  [ 4] .symtab           SYMTAB           0000000000000000  00002048
       00000000000000d8  0000000000000018           5     5     8
  [ 5] .strtab           STRTAB           0000000000000000  00002120
       000000000000002c  0000000000000000           0     0     1
  [ 6] .shstrtab         STRTAB           0000000000000000  0000214c
       0000000000000037  0000000000000000           0     0     1
Key to Flags:
  W (write), A (alloc), X (execute), M (merge), S (strings), I (info),
  L (link order), O (extra OS processing required), G (group), T (TLS),
  C (compressed), x (unknown), o (OS specific), E (exclude),
  l (large), p (processor specific)

There are no section groups in this file.

Program Headers:
  Type           Offset             VirtAddr           PhysAddr
                 FileSiz            MemSiz              Flags  Align
  LOAD           0x0000000000001000 0x0000000000401000 0x0000000000401000
                 0x0000000000000001 0x0000000000000001  R E    0x1000
  LOAD           0x0000000000002000 0x0000000000402000 0x0000000000402000
                 0x0000000000000044 0x0000000000000044  R      0x1000
  GNU_EH_FRAME   0x0000000000002000 0x0000000000402000 0x0000000000402000
                 0x0000000000000014 0x0000000000000014  R      0x4

 Section to Segment mapping:
  Segment Sections...
   00     foo 
   01     .eh_frame_hdr .eh_frame 
   02     .eh_frame_hdr 

There is no dynamic section in this file.

There are no relocations in this file.

The decoding of unwind sections for machine type Advanced Micro Devices X86-64 is not currently supported.

Symbol table '.symtab' contains 9 entries:
   Num:    Value          Size Type    Bind   Vis      Ndx Name
     0: 0000000000000000     0 NOTYPE  LOCAL  DEFAULT  UND 
     1: 0000000000401000     0 SECTION LOCAL  DEFAULT    1 
     2: 0000000000402000     0 SECTION LOCAL  DEFAULT    2 
     3: 0000000000402018     0 SECTION LOCAL  DEFAULT    3 
     4: 0000000000402000     0 NOTYPE  LOCAL  DEFAULT    2 __GNU_EH_FRAME_HDR
     5: 0000000000000000     0 NOTYPE  GLOBAL DEFAULT  UND _start
     6: 0000000000404000     0 NOTYPE  GLOBAL DEFAULT    3 __bss_start
     7: 0000000000404000     0 NOTYPE  GLOBAL DEFAULT    3 _edata
     8: 0000000000404000     0 NOTYPE  GLOBAL DEFAULT    3 _end

No version information found in this file.
Contents of the .eh_frame section:


00000000 0000000000000014 00000000 CIE
  Version:               1
  Augmentation:          "zR"
  Code alignment factor: 1
  Data alignment factor: -8
  Return address column: 16
  Augmentation data:     1b
  DW_CFA_def_cfa: r7 (rsp) ofs 8
  DW_CFA_offset: r16 (rip) at cfa-8
  DW_CFA_nop
  DW_CFA_nop

00000018 0000000000000010 0000001c FDE cie=00000000 pc=0000000000401000..0000000000401001
  DW_CFA_nop
  DW_CFA_nop
  DW_CFA_nop

I also see ".eh_frame" dumped when there is no ".eh_frame_hdr":

umb@ubuntu:~/tests/81$ readelf -a wo_hdr -wf
ELF Header:
  Magic:   7f 45 4c 46 02 01 01 00 00 00 00 00 00 00 00 00 
  Class:                             ELF64
  Data:                              2's complement, little endian
  Version:                           1 (current)
  OS/ABI:                            UNIX - System V
  ABI Version:                       0
  Type:                              EXEC (Executable file)
  Machine:                           Advanced Micro Devices X86-64
  Version:                           0x1
  Entry point address:               0x401000
  Start of program headers:          64 (bytes into file)
  Start of section headers:          8480 (bytes into file)
  Flags:                             0x0
  Size of this header:               64 (bytes)
  Size of program headers:           56 (bytes)
  Number of program headers:         2
  Size of section headers:           64 (bytes)
  Number of section headers:         6
  Section header string table index: 5

Section Headers:
  [Nr] Name              Type             Address           Offset
       Size              EntSize          Flags  Link  Info  Align
  [ 0]                   NULL             0000000000000000  00000000
       0000000000000000  0000000000000000           0     0     0
  [ 1] foo               PROGBITS         0000000000401000  00001000
       0000000000000001  0000000000000000  AX       0     0     1
  [ 2] .eh_frame         PROGBITS         0000000000402000  00002000
       000000000000002c  0000000000000000   A       0     0     8
  [ 3] .symtab           SYMTAB           0000000000000000  00002030
       00000000000000a8  0000000000000018           4     3     8
  [ 4] .strtab           STRTAB           0000000000000000  000020d8
       0000000000000019  0000000000000000           0     0     1
  [ 5] .shstrtab         STRTAB           0000000000000000  000020f1
       0000000000000029  0000000000000000           0     0     1
Key to Flags:
  W (write), A (alloc), X (execute), M (merge), S (strings), I (info),
  L (link order), O (extra OS processing required), G (group), T (TLS),
  C (compressed), x (unknown), o (OS specific), E (exclude),
  l (large), p (processor specific)

There are no section groups in this file.

Program Headers:
  Type           Offset             VirtAddr           PhysAddr
                 FileSiz            MemSiz              Flags  Align
  LOAD           0x0000000000001000 0x0000000000401000 0x0000000000401000
                 0x0000000000000001 0x0000000000000001  R E    0x1000
  LOAD           0x0000000000002000 0x0000000000402000 0x0000000000402000
                 0x000000000000002c 0x000000000000002c  R      0x1000

 Section to Segment mapping:
  Segment Sections...
   00     foo 
   01     .eh_frame 

There is no dynamic section in this file.

There are no relocations in this file.

The decoding of unwind sections for machine type Advanced Micro Devices X86-64 is not currently supported.

Symbol table '.symtab' contains 7 entries:
   Num:    Value          Size Type    Bind   Vis      Ndx Name
     0: 0000000000000000     0 NOTYPE  LOCAL  DEFAULT  UND 
     1: 0000000000401000     0 SECTION LOCAL  DEFAULT    1 
     2: 0000000000402000     0 SECTION LOCAL  DEFAULT    2 
     3: 0000000000000000     0 NOTYPE  GLOBAL DEFAULT  UND _start
     4: 0000000000404000     0 NOTYPE  GLOBAL DEFAULT    2 __bss_start
     5: 0000000000404000     0 NOTYPE  GLOBAL DEFAULT    2 _edata
     6: 0000000000404000     0 NOTYPE  GLOBAL DEFAULT    2 _end

No version information found in this file.
Contents of the .eh_frame section:


00000000 0000000000000014 00000000 CIE
  Version:               1
  Augmentation:          "zR"
  Code alignment factor: 1
  Data alignment factor: -8
  Return address column: 16
  Augmentation data:     1b
  DW_CFA_def_cfa: r7 (rsp) ofs 8
  DW_CFA_offset: r16 (rip) at cfa-8
  DW_CFA_nop
  DW_CFA_nop

00000018 0000000000000010 0000001c FDE cie=00000000 pc=0000000000401000..0000000000401001
  DW_CFA_nop
  DW_CFA_nop
  DW_CFA_nop

}

Since we have such differences in the behavior, should we just test the current behavior atm?
I.e. before this diff I tested "EH_FRAME Header [", now I also added a check for ".eh_frame section at offset...".
Both of them are dumped at the top level currently. Seems reasonable to test the fact we do that (with just -all)
and the order, probably?
(I am ok to change it in any way actually, but just wanted to clarify this before doing anything with it.)

100 ↗

(On Diff #223202)

Yep, probably SHT_NOTE will be the next.

[jhenderson]

LGTM.

test/tools/llvm-readobj/all.test

86–90 ↗

(On Diff #223202)

I'm confused too. Your output above even appears to be conflicted. Note that it mentions "The decoding of unwind sections for machine type Advanced Micro Devices X86-64 is not currently supported."

Anyway, probably best to file a bug to record the issue and then do as you're doing here (i.e. test the current behaviour).

[grimar]

test/tools/llvm-readobj/all.test

86–90 ↗

(On Diff #223202)

Note that it mentions "The decoding of unwind sections for machine type Advanced Micro Devices X86-64 is not currently supported."

Yes, that looks strange. I'll build the latest binutils from sources tomorrow and check what it do, then probably file a bug or prepare a patch. Thanks for review!

[grimar]

test/tools/llvm-readobj/all.test

86–90 ↗

(On Diff #223202)

I've build GNU readelf (GNU Binutils) 2.33.50.20191008 today and it still shows
"The decoding of unwind sections for machine type Advanced Micro Devices X86-64 is not currently supported."
for me when I request "-a" or "-u" (--unwind Display the unwind info (if present))

It seems to be a known one year old bug:
https://bugzilla.redhat.com/show_bug.cgi?id=1626614

And one of interesting comments is:
"A workaround is readelf -wF or -wf however, it is unclear to me why -u isn't wired up to do the same thing as -wf. Is that something worth considering?"

I am going to commit this patch and do nothing else for it atm (i.e. will not report any bugs for llvm-readelf until situation with GNU be fixed, since the current our behavior looks valid and I probably see no issues). How does it sound for you?

[jhenderson]

test/tools/llvm-readobj/all.test

86–90 ↗

(On Diff #223202)

Sounds good!

llvm/test/tools/llvm-readobj/all.test

 # RUN: yaml2obj %s -o %t.o
-# RUN: llvm-readobj -a %t.o | FileCheck %s --check-prefix ALL
-# RUN: llvm-readobj --all %t.o | FileCheck %s --check-prefix ALL
+# RUN: llvm-readobj -a %t.o | FileCheck %s --check-prefix LLVM-ALL
+# RUN: llvm-readobj --all %t.o | FileCheck %s --check-prefix LLVM-ALL
 
-# ALL: Format: ELF32-i386
-# ALL: Arch: i386
-# ALL: AddressSize: 32bit
-# ALL: LoadName:
-# ALL: ElfHeader {
-# ALL: Sections [
-# ALL: Relocations [
-# ALL: Symbols [
-# ALL: ProgramHeaders [
-# ALL: Version symbols {
-# ALL: SHT_GNU_verdef {
-# ALL: SHT_GNU_verneed {
-# ALL: Addrsig [
-# ALL: Notes [
-# ALL: StackSizes [
+# LLVM-ALL: Format: ELF32-i386
+# LLVM-ALL: Arch: i386
+# LLVM-ALL: AddressSize: 32bit
+# LLVM-ALL: LoadName:
+# LLVM-ALL: ElfHeader {
+# LLVM-ALL: Sections [
+# LLVM-ALL: Relocations [
+# LLVM-ALL: Symbols [
+# LLVM-ALL: ProgramHeaders [
+# LLVM-ALL: Version symbols {
+# LLVM-ALL: SHT_GNU_verdef {
+# LLVM-ALL: SHT_GNU_verneed {
+# LLVM-ALL: Addrsig [
+# LLVM-ALL: Notes [
+# LLVM-ALL: StackSizes [
+
+# RUN: llvm-readelf -a %t.o | FileCheck %s --check-prefix GNU-ALL
+# RUN: llvm-readelf --all %t.o | FileCheck %s --check-prefix GNU-ALL
+
+# GNU-ALL: ELF Header:
+# GNU-ALL: There are {{.*}} section headers, starting at offset {{.*}}:
+# GNU-ALL: Relocation section '.rela.data' at offset {{.*}} contains {{.*}} entries:
+# GNU-ALL: Symbol table '.symtab' contains {{.*}} entries:
+# GNU-ALL: EH_FRAME Header [
+# GNU-ALL: .eh_frame section at offset {{.*}} address 0x0:
+# GNU-ALL: Dynamic section at offset {{.*}} contains {{.*}} entries:
+# GNU-ALL: Program Headers:
+# GNU-ALL: Version symbols section '.gnu.version' contains {{.*}} entries:
+# GNU-ALL: Version definition section '.gnu.version_d' contains {{.*}} entries:
+# GNU-ALL: Version needs section '.gnu.version_r' contains {{.*}} entries:
+# GNU-ALL: There are no section groups in this file.
+# GNU-ALL: Histogram for bucket list length (total of 1 buckets)
+# GNU-ALL: Displaying notes found at file offset {{.*}} with length {{.*}}:
 
 --- !ELF
 FileHeader:
   Class:   ELFCLASS32
   Data:    ELFDATA2LSB
   Type:    ET_REL
   Machine: EM_386
+Sections:
+  - Name: .data
+    Type: SHT_PROGBITS
+  - Name: .rela.data
+    Type: SHT_REL
+    Relocations:
+  - Name:    .gnu.version
+    Type:    SHT_GNU_versym
+    Entries: [ 0 ]
+  - Name:    .gnu.version_d
+    Type:    SHT_GNU_verdef
+    Info:    0x0
+    Entries: []
+  - Name: .gnu.version_r
+    Type: SHT_GNU_verneed
+    Info: 0x0
+    Dependencies:
+      - Version: 1
+        File:    verneed1.so.0
+        Entries: []
+  - Name:         .dynamic
+    Type:         SHT_DYNAMIC
+    Address:      0x1000
+    AddressAlign: 0x1000
+    Entries:
+      - Tag:   DT_HASH
+        Value: 0x1100
+      - Tag:   DT_NULL
+        Value: 0
+  - Name:         .hash
+    Type:         SHT_HASH
+    Link:         0
+    Bucket:       [ 1 ]
+    Chain:        [ 0, 0 ]
+    Address:      0x1100
+    AddressAlign: 0x100
+  - Name:    .eh_frame_hdr
+    Type:    SHT_PROGBITS
+## An arbitrary linker-generated valid content.
+    Content: 011b033b140000000100000000f0ffff30000000
+  - Name:         .eh_frame
+    Type:         SHT_PROGBITS
+    AddressAlign: 8
+## An arbitrary linker-generated valid content.
+    Content:      1400000000000000017a5200017810011b0c070890010000100000001c000000c8efffff0100000000000000
+  - Name:    .note.gnu.build-id
+    Type:    SHT_NOTE
+    Flags:   [ SHF_ALLOC ]
+    Address: 0x1500
+## An arbitrary linker-generated valid content.
+    Content: 040000001000000003000000474E55004FCB712AA6387724A9F465A32CD8C14B
+ProgramHeaders:
+  - Type:  PT_LOAD
+    VAddr: 0x1000
+    Sections:
+      - Section: .dynamic
+      - Section: .hash
+  - Type: PT_DYNAMIC
+    Sections:
+      - Section: .dynamic
+  - Type: PT_GNU_EH_FRAME
+    Sections:
+      - Section: .eh_frame_hdr
+  - Type: PT_NOTE
+    Sections:
+      - Section: .note.gnu.build-id