NAME

dwarf_add_frame_fde — add a call frame descriptor to a DWARF producer instance

LIBRARY

DWARF Access Library (libdwarf, -ldwarf)

SYNOPSIS

#include <libdwarf.h>

Dwarf_Unsigned
dwarf_add_frame_fde(Dwarf_P_Debug dbg, Dwarf_P_Fde fde, Dwarf_P_Die die, Dwarf_Unsigned cie, Dwarf_Addr virt_addr, Dwarf_Unsigned code_len, Dwarf_Unsigned symbol_index, Dwarf_Error *err);

Dwarf_Unsigned
dwarf_add_frame_fde_b(Dwarf_P_Debug dbg, Dwarf_P_Fde fde, Dwarf_P_Die die, Dwarf_Unsigned cie, Dwarf_Addr virt_addr, Dwarf_Unsigned code_len, Dwarf_Unsigned symbol_index, Dwarf_Unsigned end_symbol_index, Dwarf_Addr offset_from_end_sym, Dwarf_Error *err);

DESCRIPTION

Function dwarf_add_frame_fde_b() adds the call frame descriptor referenced by argument fde to a producer instance.

Argument dbg should reference a DWARF producer instance allocated using dwarf_producer_init(3) or dwarf_producer_init_b(3).

Argument fde should reference a frame descriptor allocated using dwarf_new_fde(3).

Argument die is ignored by this implementation of the DWARF Access Library (libdwarf, -ldwarf).

Argument cie specifies the index of call frame common information entry for the frame descriptor. Valid indices are those returned by the function dwarf_add_frame_cie(3).

Argument symbol_index specifies the ELF symbol index of the first symbol to be used for relocation.

The meaning of the arguments virt_addr, code_len and offset_from_end_sym depend on the value of argument end_symbol_index:

If the argument end_symbol_index is zero, the argument virt_addr specifies the relocatable address of the start of the function associated with the frame descriptor, the argument code_len specifies the size in bytes of the machine instructions for this function, the argument symbol_index specifies the ELF symbol to be used for relocating the address in argument virt_addr, and the argument offset_from_end_symbol is ignored.
If the argument end_symbol_index is non-zero, it specifies the ELF symbol index of the second symbol to be used for relocation. In this case, the argument virt_addr specifies an offset from the relocatable symbol specified by argument symbol_index, the argument offset_from_end_symbol should specify an offset from the symbol named by the argument end_symbol_index, and the argument code_len will be ignored. The DW_DLC_SYMBOLIC_RELOCATIONS flag should also have been set on the DWARF producer instance.
Application code can retrieve the relocation entries for the symbol pair by calling function dwarf_get_relocation_info(3). The relocation entry for the first symbol will have type dwarf_drt_first_of_length_pair and the relocation entry for the second symbol will have type dwarf_drt_second_of_length_pair.

If argument err is not NULL, it will be used to store error information in case of an error.

Function dwarf_add_frame_fde() is similar to function dwarf_add_frame_fde_b() except that it supports only one relocation symbol.

RETURN VALUES

On success, these functions return the index value for the added frame descriptor. In case of an error, these functions return DW_DLV_NOCOUNT and set the argument err.

ERRORS

These functions can fail with:

[DW_DLE_ARGUMENT]: One of the arguments dbg or fde was NULL.
[DW_DLE_ARGUMENT]: The frame descriptor referenced by argument fde did not belong to the producer instance referenced by argument dbg.
[DW_DLE_ARGUMENT]: The common information entry index specified by argument cie was invalid.
[DW_DLE_ARGUMENT]: Argument end_symbol_index was non-zero, but the flag DW_DLC_SYMBOLIC_RELOCATIONS was not set on the producer instance.