Wrong basic block boundaries in several binaries

I've noticed a few places where the ground truth seems to be wrong. This is, I believe, and different case from https://github.com/junxzm1990/x86-sok/issues/28 where capstone was to blame. In the following cases, the extract_gt script reports errors.

intel_executables/cpu2006/clang_Os/dealII_base.amd64-m64-ccr-Os

There is a fragment of code that looks like this:

__cxx_global_var_init.8:

          404027:   push RAX
          404028:   cmp BYTE PTR [RIP+_ZGVN4Data5SetUpINS_12Exercise_2_3ILi3EEELi3EE15right_hand_sideE],0
          40402f:   jne .L_40407d
          404031:   movsd XMM0,QWORD PTR [RIP+.L_57a5c8]
          404039:   mov EDI,OFFSET _ZN4Data5SetUpINS_12Exercise_2_3ILi3EEELi3EE15right_hand_sideE
          40403e:   mov ESI,1
          404043:   call _ZN16ConstantFunctionILi3EEC1Edj
...

But 404043: call _ZN16ConstantFunctionILi3EEC1Edj is not part of the ground truth, even though 40403e belongs to it. The extract_gt script produces the following output:

  BBL#29709 ( 18B) @0x00404031 - 0x00404043, BaseOff: 0x4031, SecOff:0x0621, Fixups: 0 , Type: BBL, Padding: 0x0, Fallthrough: Y
    BBL#29710 ( 10B) @0x00404027 - 0x00404031, BaseOff: 0x4027, SecOff:0x0617, Fixups: 0 , Type: FUN&&OBJ, Padding: 0x0, Fallthrough: N
    BBL#29711 ( 18B) @0x00404031 - 0x00404043, BaseOff: 0x4031, SecOff:0x0621, Fixups: 0 , Type: FUN&&OBJ, Padding: 0x0, Fallthrough: N
...
INFO:Found Gaps#1 in section .text, between 0x404043 - 0x4040d9, size: 150
...
INFO:Terminator 0x40403e:   mov esi, 1 is not JUMP , RET or JUMP
ERROR:291:successor addr 404043 not in basic block list
INFO:block 0x404031 to 0x404043, type is 0
WARNING:Terminator inst of BasicBlock 404027 does not have a fixup?
INFO:block 0x404027 to 0x404031, type is 0
INFO:Terminator 0x40403e:   mov esi, 1 is not JUMP , RET or JUMP
ERROR:The basic block 404031-404043 does not end of JUMP or RET, and is not FALLTHROUGH!. its instruction is 0x40403e:  mov esi, 1
INFO:block 0x404031 to 0x404043, type is 0

What could cause this instruction to be missing?

milc_base.aarch64-ccr-O2

dclock:
          4168bc:   fmov d0,xzr
          4168c0:   ret

The 4168c0: ret instruction is missing from the ground truth (even though 4168bc: fmov d0,xzr is present).

The extract_gt log:

   BBL#2621 (  4B) @0x004168bc - 0x004168c0, BaseOff: 0x168bc, SecOff:0x15934, Fixups: 0 , Type: FUN, Padding: 0x0, Fallthrough: N
    BBL#2622 (  4B) @0x004168bc - 0x004168c0, BaseOff: 0x168bc, SecOff:0x15934, Fixups: 0 , Type: FUN, Padding: 0x0, Fallthrough: N
... 
INFO:Found Gaps#0 in section .text, between 0x4168c0 - 0x4168c4, size: 4
...
ERROR:The basic block 4168bc-4168c0 does not end of JUMP or RET, and is not FALLTHROUGH!. its instruction is 0x4168bc:  fmov    d0, xzr
INFO:block 0x4168bc to 0x4168c0, type is 0
INFO:Terminator 0x4168bc:   fmov    d0, xzr is not JUMP , RET or JUMP
ERROR:The basic block 4168bc-4168c0 does not end of JUMP or RET, and is not FALLTHROUGH!. its instruction is 0x4168bc:  fmov    d0, xzr
INFO:block 0x4168bc to 0x4168c0, type is 0

Same, what could be going wrong here? One thing I notice is that the basic block seems to be duplicated in these two examples. E.g. in the latter, we have BBL#2621 and BBL#2622 with the same boundaries. Could that have something to do?

soplex_base.arm32-gcc81-mthumb_final-O2

Here we have the following snippet:

          18232:   movs r3, #0
          18234:   ldr r3, [r3]
          18236:   udf #255

The udf instruction is missing from the ground truth, even though 18234: ldr r3, [r3] is present.

This pattern is generated when there is a null pointer access (see e.g. https://embedded.fm/blog/2017/3/6/exceptional-code) The extract_gt log contains the following:

 BBL#4282 (  4B) @0x00018232 - 0x00018236, BaseOff: 0x10232, SecOff:0xe932, Fixups: 0 , Type: TFUN, Padding: 0x0, Fallthrough: N
    BBL#4283 ( 12B) @0x00018238 - 0x00018244, BaseOff: 0x10238, SecOff:0xe938, Fixups: 0 , Type: TBBL, Padding: 0x0, Fallthrough: Y
...
INFO:Found Gaps#69 in section .text, between 0x18236 - 0x18238, size: 2
...
INFO:Terminator 0x18234:    ldr r3, [r3] is not JUMP , RET or JUMP
ERROR:The basic block 18232-18236 does not end of JUMP or RET, and is not FALLTHROUGH!. its instruction is 0x18234: ldr r3, [r3]
INFO:block 0x18232 to 0x18236, type is 0

This pattern in particular happens in a lot of the thumb binaries and the udf instruction seems to be missing every time (in close to 200 binaries). I would guess this is a different issue than the previous two.

Hello, the first two bugs arose from improper handling of duplicate sections.

The __cxx_global_var_init.8 was introduced following the compilation of step-14.cc, and the disassembly results are presented below:

Disassembly of section .text.startup:

0000000000000000 <__cxx_global_var_init.7>:
   0:   50                      push   %rax
   1:   80 3d 00 00 00 00 00    cmpb   $0x0,0x0(%rip)        # 8 <__cxx_global_var_init.7+0x8>
   8:   75 2e                   jne    38 <__cxx_global_var_init.7+0x38>
   a:   bf 00 00 00 00          mov    $0x0,%edi
   f:   be 01 00 00 00          mov    $0x1,%esi
  14:   e8 00 00 00 00          callq  19 <__cxx_global_var_init.7+0x19>
  19:   bf 00 00 00 00          mov    $0x0,%edi
  1e:   be 00 00 00 00          mov    $0x0,%esi
  23:   ba 00 00 00 00          mov    $0x0,%edx
  28:   e8 00 00 00 00          callq  2d <__cxx_global_var_init.7+0x2d>
  2d:   48 c7 05 00 00 00 00    movq   $0x1,0x0(%rip)        # 38 <__cxx_global_var_init.7+0x38>
  34:   01 00 00 00
  38:   58                      pop    %rax
  39:   c3                      retq

Disassembly of section .text.startup:

0000000000000000 <__cxx_global_var_init.8>:
   0:   50                      push   %rax
   1:   80 3d 00 00 00 00 00    cmpb   $0x0,0x0(%rip)        # 8 <__cxx_global_var_init.8+0x8>
   8:   75 4c                   jne    56 <__cxx_global_var_init.8+0x56>
   a:   f2 0f 10 05 00 00 00    movsd  0x0(%rip),%xmm0        # 12 <__cxx_global_var_init.8+0x12>
  11:   00
  12:   bf 00 00 00 00          mov    $0x0,%edi
  17:   be 01 00 00 00          mov    $0x1,%esi
  1c:   e8 00 00 00 00          callq  21 <__cxx_global_var_init.8+0x21>
  21:   48 c7 05 00 00 00 00    movq   $0x0,0x0(%rip)        # 2c <__cxx_global_var_init.8+0x2c>
  28:   00 00 00 00
  2c:   48 c7 05 00 00 00 00    movq   $0x0,0x0(%rip)        # 37 <__cxx_global_var_init.8+0x37>
  33:   00 00 00 00
  37:   bf 00 00 00 00          mov    $0x0,%edi
  3c:   be 00 00 00 00          mov    $0x0,%esi
  41:   ba 00 00 00 00          mov    $0x0,%edx
  46:   e8 00 00 00 00          callq  4b <__cxx_global_var_init.8+0x4b>
  4b:   48 c7 05 00 00 00 00    movq   $0x1,0x0(%rip)        # 56 <__cxx_global_var_init.8+0x56>
  52:   01 00 00 00
  56:   58                      pop    %rax
  57:   c3                      retq

The ground truth is correct after compling step-14.cc:

       BBL# 293 ( 10B) [BBL] - Off:0x0000, Fixups:  2, padding:  0, FallThrough: Y (@Sec .text.startup)  [DUP]
        BBL# 294 ( 46B) [BBL] - Off:0x000a, Fixups:  7, padding:  0, FallThrough: Y (@Sec .text.startup)
        BBL# 295 (  2B) [FUN&&OBJ] - Off:0x0038, Fixups:  0, padding:  0, FallThrough: N (@Sec .text.startup)
        BBL# 296 ( 10B) [BBL] - Off:0x0000, Fixups:  2, padding:  0, FallThrough: Y (@Sec .text.startup)  [DUP]
        BBL# 297 ( 76B) [BBL] - Off:0x000a, Fixups: 12, padding:  0, FallThrough: Y (@Sec .text.startup)  [DUP]
        BBL# 298 (  2B) [FUN&&OBJ] - Off:0x0056, Fixups:  0, padding:  0, FallThrough: N (@Sec .text.startup)  [DUP]
        BBL# 299 ( 10B) [BBL] - Off:0x0000, Fixups:  2, padding:  0, FallThrough: Y (@Sec .text.startup)  [DUP]
        BBL# 300 ( 46B) [BBL] - Off:0x000a, Fixups:  7, padding:  0, FallThrough: Y (@Sec .text.startup)  [DUP]
        BBL# 301 (  2B) [FUN&&OBJ] - Off:0x0038, Fixups:  0, padding:  0, FallThrough: N (@Sec .text.startup)  [DUP]

However, step-14.o contains duplicate sections(.text.startup), and the linker fails to handle them appropriately.

Note that there are four special sections that need to be handled. The compiled dealII.zip after fixing is attached.

Hello, for the third case, we identified that the root cause is the incorrect handling of the .inst 0xdeff pseudo code. Instead of generating the instruction udf #255, the GCC compiler emits the .inst pseudo code. Below is the example:

        bl      bfd_assert
        movs    r3, #0
        ldr     r3, [r3, #360]
        .bbInfo_BE 0
        .inst   0xdeff
        .bbInfo_FUNE

We are planing to handle the corner case in gas assembler.

Thanks a lot for the quick response! I guess that means some of the binaries need to be rebuilt. Right? Do you have by any chance scripts for rebuilding the complete datasets (https://zenodo.org/record/6566082/)? I've looked around but all the scripts seem to assume the binaries have been prebuilt.

For completeness (for other people using this dataset), some arm (non-thumb) binaries have also problems with udf. In that case with udf #0 instead of udf 255. Most versions of dwp and one version of ls.gold.

For each binary, I provide a snippet of assembly where "GOOD" instructions are instructions present in the ground truth, and "BAD" instructions are absent. In all of these, "GOOD" instructions must fallthrough to "BAD" instructions, which tells me something wrong is going on with the ground truth.

arm32_executables/utils/binutils/gcc_Os/ld.gold

GOOD 0x2736b8 mov r3, #0
GOOD 0x2736bc str r3, [sp, #4]
GOOD 0x2736c0 ldr r3, [r3, #8]
BAD  0x2736c4 udf #0

arm32_executables/utils/binutils/gcc_Of/dwp

GOOD 0x233578 mov r3, #0
GOOD 0x23357c str r3, [sp, #4]
GOOD 0x233580 ldr r3, [r3, #8]
BAD  0x233584 udf #0

Here is a list of all the other binaries where I have found inconsistent ground truth. Some of these might be due to the duplicate section problem or maybe there is something else going on.

aarch64

aarch64_executables/cpu2006/clang_O2_64/hmmer_base.aarch64-ccr-O2
```
GOOD 0x414138 fmov s0, wzr
BAD  0x41413c ret
```
aarch64_executables/cpu2006/clang_O2_64/gobmk_base.aarch64-ccr-O2
```
GOOD 0x49ab00 fmov d0, xzr
BAD  0x49ab04 ret
```
aarch64_executables/cpu2006/clang_O2_64/dealII_base.aarch64-ccr-O2
```
GOOD 0x4f4344 fmov d0, xzr
BAD  0x4f4348 ret
```
- aarch64_executables/cpu2006/clang_O2_64/Xalan_base.aarch64-ccr-O2
```
GOOD 0x587960 fmov d0, xzr
BAD  0x587964 ret
```

x86

cpu2006/clang_m32_Os/dealII_base.amd64-m32-ccr-Os

GOOD 0x81c1827 add byte ptr [ebx + 0x31042444], cl
BAD  0x81c182d leave
GOOD 0x81c182e mov dword ptr [eax], 0x8240954

libs/clang_m32_Of/libxml2.so

GOOD 0x59045 pop ecx
GOOD 0x59046 mov eax, 0xffffffff
GOOD 0x5904b add ecx, 0x116faf
GOOD 0x59051 mov edx, dword ptr [ecx + 0x9ac]
BAD  0x59057 cmp edx, 0xe
BAD  0x5905a jg 0x590a7

libs/gcc_m32_Os/stlOfXIA

GOOD 0xcf851 lea ecx, [ebx + ebx]
GOOD 0xcf854 shr eax, cl
BAD  0xcf856 and eax, 3

/libs/clang_m32_O1/libpcap.so.1.9.0

GOOD 0x60d5 pop eax
BAD  0x60d6 add eax, 0x33f1f
GOOD 0x60dc cmp ecx, 4

/libs/clang_m32_Of/libpcap.so.1.9.0

GOOD 0xf4b6 mov dword ptr [ecx + 0x30], edx
GOOD 0xf4b9 mov dword ptr [eax + 0x2cc], ecx
BAD  0xf4bf ret

cpu2006/clang_Of/dealII_base.amd64-m64-ccr-Of In this case there is an address in the ground truth at 0x403be5 but if we look at the disassembly of the unstripped version, there is a symbol at 403be0 and the following assembly code:

0000000000403be0 <_GLOBAL__sub_I_sparse_matrix_ez.float.cc>:
403be0:   50                      push   %rax
403be1:   bf 4b cd 78 00          mov    $0x78cd4b,%edi
403be6:   e8 95 f3 ff ff          callq  402f80 <_ZNSt8ios_base4InitC1Ev@plt>
403beb:   bf 90 2f 40 00          mov    $0x402f90,%edi

I think it is very unlikely that 0x403be5 is a real instruction.

junxzm1990 / x86-sok