[BOLT][AArch64] After BOLT optimization, .so crashes and the call information cannot be viewed.

[sig-loha-huang]

When a crash occurs in a .so file optimized with BOLT (Binary Optimization and Layout Tool), conventional debugging methods cannot obtain complete call stack information. How can this issue be resolved?

[llvmbot]

@llvm/issue-subscribers-bolt

Author: sig-loha-lh (sig-loha-huang)

When a crash occurs in a .so file optimized with BOLT (Binary Optimization and Layout Tool), conventional debugging methods cannot obtain complete call stack information. How can this issue be resolved?

[paschalis-mpeis]

Did your original binary have debug info attached to it? By default BOLT drops it, but you can preserve it with:

llvm-bolt --update-debug-sections ...

Would that help?

[sig-loha-huang]

hi @paschalis-mpeis ,
Thank you very much for your reply!!!

   1. We will try to use --update-debug-sections in BOLT's optimization command.
   
   2. But
   When Android compiling, two files will be compiled: stripped and not stripped. 
   The files that are actually run in Andorid are also not tripped files.  ---> when crash have call information
   BOLT uses not stripped files for optimization and generates stripped files.  --->when crash don't have call information

   The final file used is also the stripped file in android,  so when crash occurs in a .so file optimized with BOLT, we don't know why?

Br

[sig-loha-huang]

Hi @paschalis-mpeis
when i use --update-debug-sections , The following problem occurred, Have you encountered this problem before?
.debug_line_strBOLT-ERROR: could not extract string from .debug_line_strBOLT-ERROR: could not extract string from .debug_line_strBOLT-ERROR: could not extract string from .debug_line_strBOLT-ERROR: could not extract string from

BOLT-INFO: shared object or position-independent executable detected
BOLT-INFO: Target architecture: aarch64
BOLT-INFO: BOLT version: b718bcaf8c198c82f3021447d943401e3ab5bd54
BOLT-INFO: first alloc address is 0x0
BOLT-INFO: creating new program header table at address 0xc0000, offset 0xc0000
BOLT-INFO: enabling strict relocation mode
BOLT-INFO: pre-processing profile using branch profile reader
BOLT-INFO: number of removed linker-inserted veneers: 0
BOLT-INFO: 356 out of 1663 functions in the binary (21.4%) have non-empty execution profile
BOLT-INFO: 1 function with profile could not be optimized
BOLT-WARNING: 226 (63.5% of all profiled) functions have invalid (possibly stale) profile. Use -report-stale to see the list.
BOLT-WARNING: 7884266 out of 8159387 samples in the binary (96.6%) belong to functions with invalid (possibly stale) profile.
BOLT-INFO: 0 stale functions (0.0% of all stale) have matching block count.
BOLT-INFO: 0 stale blocks (-nan% of all stale) have matching icount.
BOLT-INFO: profile for 97 objects was ignored
BOLT-INFO: basic block reordering modified layout of 18 functions (5.06% of profiled, 0.83% of total)
BOLT-INFO: 0 Functions were reordered by LoopInversionPass
BOLT-INFO: program-wide dynostats after all optimizations before SCTC and FOP:

          145771 : executed forward branches
            2778 : taken forward branches
              10 : executed backward branches
               2 : taken backward branches
             183 : executed unconditional branches
          222179 : all function calls
           71478 : indirect calls
           66911 : PLT calls
         1327866 : executed instructions
          261886 : executed load instructions
               0 : executed store instructions
               0 : taken jump table branches
               0 : taken unknown indirect branches
          145964 : total branches
            2963 : taken branches
          143001 : non-taken conditional branches
            2780 : taken conditional branches
          145781 : all conditional branches
               0 : linker-inserted veneer calls

          145663 : executed forward branches (-0.1%)
               0 : taken forward branches (-100.0%)
             118 : executed backward branches (+1080.0%)
               2 : taken backward branches (=)
             274 : executed unconditional branches (+49.7%)
          222179 : all function calls (=)
           71478 : indirect calls (=)
           66911 : PLT calls (=)
         1368456 : executed instructions (+3.1%)
          261886 : executed load instructions (=)
               0 : executed store instructions (=)
               0 : taken jump table branches (=)
               0 : taken unknown indirect branches (=)
          146055 : total branches (+0.1%)
             276 : taken branches (-90.7%)
          145779 : non-taken conditional branches (+1.9%)
               2 : taken conditional branches (-99.9%)
          145781 : all conditional branches (=)
               0 : linker-inserted veneer calls (=)

BOLT-INFO: Starting stub-insertion pass
BOLT-INFO: Inserted 11 stubs in the hot area and 1 stubs in the cold area. Shared 0 times, iterated 3 times.
BOLT-ERROR: could not extract string from .debug_line_strBOLT-ERROR: could not extract string from .debug_line_strBOLT-ERROR: could not extract string from .debug_line_strBOLT-ERROR: could not extract string from .debug_line_strBOLT-ERROR: could not extract string from .debug_line_strBOLT-ERROR: could not extract string from .debug_line_strBOLT-ERROR: could not extract string from .debug_line_strBOLT-ERROR: could not extract string from .debug_line_strBOLT-ERROR: could not extract string from .debug_line_strBOLT-ERROR: could not extract string from .debug_line_strBOLT-ERROR: could not extract string from .debug_line_strBOLT-ERROR: could not extract string from .debug_line_strBOLT-ERROR: could not extract string from .debug_line_strBOLT-ERROR: could not extract string from .debug_line_strBOLT-ERROR: could not extract string from .debug_line_strBOLT-ERROR: could not extract string from .debug_line_strBOLT-ERROR: could not extract string from .debug_line_strBOLT-ERROR: could not extract string from .debug_line_strBOLT-ERROR: could not extract string from .debug_line_strBOLT-ERROR: could not extract string from .debug_line_strBOLT-ERROR: could not extract string from .debug_line_strBOLT-ERROR: could not extract string from .debug_line_strBOLT-ERROR: could not extract string from .debug_line_strBOLT-ERROR: could not extract string from .debug_line_strBOLT-ERROR: could not extract string from .debug_line_strBOLT-ERROR: could not extract string from .debug_line_strBOLT-ERROR: could not extract string from .debug_line_strBOLT-ERROR: could not extract string from .debug_line_strBOLT-ERROR: could not extract string from .debug_line_strBOLT-ERROR: could not extract string from .debug_line_strBOLT-ERROR: could not extract string from .debug_line_strBOLT-ERROR: could not extract string from .debug_line_strBOLT-ERROR: could not extract string from .debug_line_strBOLT-ERROR: could not extract string from .debug_line_strBOLT-ERROR: could not extract string from .debug_line_strBOLT-ERROR: could not extract string from .debug_line_strBOLT-ERROR: could not extract string from .debug_line_strBOLT-ERROR: could not extract string from .debug_line_strBOLT-ERROR: could not extract string from .debug_line_strBOLT-ERROR: could not extract string from .debug_line_strBOLT-ERROR: could not extract string from .debug_line_strBOLT-ERROR: could not extract string from .debug_line_strBOLT-ERROR: could not extract string from .debug_line_strBOLT-ERROR: could not extract string from .debug_line_strBOLT-ERROR: could not extract string from .debug_line_strBOLT-ERROR: could not extract string from .debug_line_strBOLT-ERROR: could not extract string from .debug_line_strBOLT-ERROR: could not extract string from .debug_line_strBOLT-ERROR: could not extract string from .debug_line_strBOLT-ERROR: could not extract string from .debug_line_strBOLT-ERROR: could not extract string from .debug_line_strBOLT-ERROR: could not extract string from .debug_line_strBOLT-ERROR: could not extract string from .debug_line_strBOLT-ERROR: could not extract string from .debug_line_strBOLT-ERROR:

[sig-loha-huang]

The same problem occurs for the not stripped file after Bolt optimization.

file /system/lib64/libbinder.so
/system/lib64/libbinder.so: ELF shared object, 64-bit LSB arm64, for Android 36, BuildID=bf133b5dd518051e6fb3505b114c74a0, not stripped

"binder:1999_1" sysTid=2735
    #00 pc 00000000000d748c  /apex/com.android.runtime/lib64/bionic/libc.so (__ioctl+12) (BuildId: c9086d9676a185b767a769c6277d5c6d)
    #01 pc 000000000007d428  /apex/com.android.runtime/lib64/bionic/libc.so (ioctl+156) (BuildId: c9086d9676a185b767a769c6277d5c6d)
    #02 pc 00000000000e4a28  /system/lib64/libbinder.so (android::IPCThreadState::talkWithDriver(bool)+232) (BuildId: bf133b5dd518051e6fb3505b114c74a0)
    #03 pc 007f3cf9f2d3249c  <unknown>

"binder:1999_2" sysTid=2736
    #00 pc 00000000000d748c  /apex/com.android.runtime/lib64/bionic/libc.so (__ioctl+12) (BuildId: c9086d9676a185b767a769c6277d5c6d)
    #01 pc 000000000007d428  /apex/com.android.runtime/lib64/bionic/libc.so (ioctl+156) (BuildId: c9086d9676a185b767a769c6277d5c6d)
    #02 pc 00000000000e4a28  /system/lib64/libbinder.so (android::IPCThreadState::talkWithDriver(bool)+232) (BuildId: bf133b5dd518051e6fb3505b114c74a0)
    #03 pc 004ccaf9f2d3249c  <unknown>

[sig-loha-huang]

hi @paschalis-mpeis
This was solved with the patch you mentioned earlier. Thank you very much for your support.
#120064

[paschalis-mpeis]

Sorry I haven't followed the latest developments but I'm glad my earlier suggestion worked.

That was a good use of @bgergely0 work. Please report any issues/feedback to us at #120064.