[llvm-dev] GDB doesn't work with IR-originated debug info

[Aliaksei Zasenka via llvm-dev]

Hi all,

Need your help.

I added some debug information to my code according to Kaleidoscope-9
sample and got stuck with a GDB error:

(gdb) info functions
> invalid dwarf2 offset 1849950870
>

My module is a DLL built with llc+ld toolchain. Target triple:
'i686-w64-mingw32'.
Looking this offset (1849950870 == 0x6e440296) in dwarfdump output of the
dll gave the following:

0x00000296:   DW_TAG_base_type [10]
                DW_AT_name [DW_FORM_strp]    ( .debug_str[0x0000068f] =
"void")
                DW_AT_encoding [DW_FORM_data1]    (0x00)
                DW_AT_byte_size [DW_FORM_data1]    (0x00)
....
0x00000cf8:   DW_TAG_subprogram [16] *
                DW_AT_low_pc [DW_FORM_addr]    (0x000000006e384c30)
                DW_AT_high_pc [DW_FORM_data4]    (0x000002b4)
                DW_AT_frame_base [DW_FORM_exprloc]    (<0x1> 54 )
                DW_AT_name [DW_FORM_strp]    ( .debug_str[0x00001616] =
"FB_FPUMP at HORIZONTAL")
                DW_AT_type [DW_FORM_ref_addr]    (*0x000000006e440296*)
                DW_
AT_external [DW_FORM_flag_present]    (true)


In the original object file the corresponding record was:

0x00000296:   DW_TAG_base_type [10]
                DW_AT_name [DW_FORM_strp]    ( .debug_str[0x0000068f] =
"void")
                DW_AT_encoding [DW_FORM_data1]    (0x00)
                DW_AT_byte_size [DW_FORM_data1]    (0x00)
....

0x00000cf8:   DW_TAG_subprogram [16] *
                DW_AT_low_pc [DW_FORM_addr]    (0x00000000000037e0)
                DW_AT_high_pc [DW_FORM_data4]    (0x000002b4)
                DW_AT_frame_base [DW_FORM_exprloc]    (<0x1> 54 )
                DW_AT_name [DW_FORM_strp]    ( .debug_str[0x00001616] =
"FB_FPUMP at HORIZONTAL")
                DW_AT_type [DW_FORM_ref_addr]    (*0x0000000000000296*)
                DW_AT_external [DW_FORM_flag_present]    (true)


There are lots of subprogram records like this.

Any ideas what may be done to fix that?

My debugger config:
GNU gdb (GDB) 7.10.1
This GDB was configured as "i686-w64-mingw32".
OS : Win7 64-bit

--
Best regards,
Alexey Zasenko
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