DWARF_ADD_FRAME_FDE(3) | Library Functions Manual | DWARF_ADD_FRAME_FDE(3)

# 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.

# SEE ALSO

dwarf(3), dwarf_add_fde_inst(3), dwarf_add_frame_cie(3), dwarf_fde_cfa_offset(3), dwarf_get_relocation_info(3), dwarf_new_fde(3), dwarf_producer_init(3), dwarf_producer_init_b(3)

September 26, 2011 | NetBSD 9.2