I'm trying to find structure member memory address(Non Virtual Memory, embedded) from dwarf.
And there's two things i don't understand.
First, In below dwarf Info1 DW_AT_location value = [3, 192, 63, 2, 128].
According to dwarf standards, [192, 63, 2, 128] is a address which encoded unsigned LEB128 and little endian.
But when i check this structure variable memory adress using other third party software, memory address is 0x80023fc0.
It means [192, 63, 2, 128] is not encoded unsigned LEB128, but it just little endian decimal.
Please explain why it happens.(i parse dwarf information using python elftools module)
DIE DW_TAG_variable, size=37, has_children=False
|DW_AT_name : AttributeValue(name='DW_AT_name', form='DW_FORM_string', value=b'apCalVariant_Appl_LCS', raw_value=b'apCalVariant_Appl_LCS', offset=26734224)
|DW_AT_decl_file : AttributeValue(name='DW_AT_decl_file', form='DW_FORM_udata', value=38, raw_value=38, offset=26734246)
|DW_AT_decl_line : AttributeValue(name='DW_AT_decl_line', form='DW_FORM_udata', value=8, raw_value=8, offset=26734247)
|DW_AT_decl_column : AttributeValue(name='DW_AT_decl_column', form='DW_FORM_udata', value=24, raw_value=24, offset=26734248)
|DW_AT_type : AttributeValue(name='DW_AT_type', form='DW_FORM_ref_addr', value=6023079, raw_value=6023079, offset=26734249)
|DW_AT_external : AttributeValue(name='DW_AT_external', form='DW_FORM_flag', value=True, raw_value=1, offset=26734253)
|DW_AT_location : AttributeValue(name='DW_AT_location', form='DW_FORM_block', value=[3, 192, 63, 2, 128], raw_value=[3, 192, 63, 2, 128], offset=26734254)
Second, In below dwarf Information there are two structure members with DW_AT_data_member_location = [35, 196, 1], [35, 144, 2].
This structure members is member of first question structure variable. (1) k_u16_LCS_VarStrTq_1En2Nm(address : 0x80024084), (2) k_s16_LCS_LacDeActvLatestCtrlLine_LCHold_1En3m(address : 0x800240D0).
I don't understand what DW_AT_data_member_location value is stands for.
k_u16_LCS_VarStrTq_1En2Nm address is structure start address(0x80023fc0) + 196(0xC4).
But k_s16_LCS_LacDeActvLatestCtrlLine_LCHold_1En3m address is not structure start address(0x80023fc0) + 144(0x90) = 0x80024050.
DIE DW_TAG_member, size=36, has_children=False
|DW_AT_name : AttributeValue(name='DW_AT_name', form='DW_FORM_string', value=b'k_u16_LCS_VarStrTq_1En2Nm', raw_value=b'k_u16_LCS_VarStrTq_1En2Nm', offset=5215310)
|DW_AT_type : AttributeValue(name='DW_AT_type', form='DW_FORM_ref4', value=312, raw_value=312, offset=5215336)
|DW_AT_byte_size : AttributeValue(name='DW_AT_byte_size', form='DW_FORM_udata', value=2, raw_value=2, offset=5215340)
|DW_AT_data_member_location: AttributeValue(name='DW_AT_data_member_location', form='DW_FORM_block', value=[35, 196, 1], raw_value=[35, 196, 1], offset=5215341)
DIE DW_TAG_member, size=57, has_children=False
|DW_AT_name : AttributeValue(name='DW_AT_name', form='DW_FORM_string', value=b'k_s16_LCS_LacDeActvLatestCtrlLine_LCHold_1En3m', raw_value=b'k_s16_LCS_LacDeActvLatestCtrlLine_LCHold_1En3m', offset=5216696)
|DW_AT_type : AttributeValue(name='DW_AT_type', form='DW_FORM_ref4', value=283, raw_value=283, offset=5216743)
|DW_AT_byte_size : AttributeValue(name='DW_AT_byte_size', form='DW_FORM_udata', value=2, raw_value=2, offset=5216747)
|DW_AT_data_member_location: AttributeValue(name='DW_AT_data_member_location', form='DW_FORM_block', value=[35, 144, 2], raw_value=[35, 144, 2], offset=5216748)
Please explain what DW_AT_data_member_location means and how can i calculate structure member addresss using it.
In advanced, Thank you for all you guys.
