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DWARF_GET_FDE_INFO_... FreeBSD Library Functions Manual	DWARF_GET_FDE_INFO_...

NAME
     dwarf_get_fde_info_for_reg3 -- retrieve register rule

LIBRARY
     DWARF Access Library (libdwarf, -ldwarf)

SYNOPSIS
     #include <libdwarf.h>

     int
     dwarf_get_fde_info_for_reg3(Dwarf_Fde fde,	Dwarf_Half table_column,
	 Dwarf_Addr pc,	Dwarf_Small *type, Dwarf_Signed	*offset_relevant,
	 Dwarf_Signed *register_num, Dwarf_Signed *offset_or_block_len,
	 Dwarf_Ptr *block_ptr, Dwarf_Addr *row_pc, Dwarf_Error *error);

DESCRIPTION
     Function dwarf_get_fde_info_for_reg3() retrieves a	register rule from the
     register rule table associated with a given FDE descriptor, given a pro-
     gram counter address and rule column number.

     Argument fde should reference a valid DWARF FDE descriptor.

     Arugment table_column should hold the column number of the	register rule
     desired.

     Argument pc should	hold the program counter address to be used to locate
     the desired register rule row.

     On	successful execution, dwarf_get_fde_info_for_reg3() stores information
     about the register	rule found into	the locations pointed to by the	argu-
     ments type, offset_relevant, register_num,	offset_or_block_len, block_ptr
     and row_pc.

     Argument type should point	to a location which will hold the type code of
     the register rule found.  The returned value is one of the	DW_EXPR_* con-
     tants defined in the header file <libdwarf.h>.

     If	there is an offset value associated with the register rule, the	loca-
     tion pointed to by	argument offset_relevant will be set to	1.

     Argument register_num should point	to a location which will hold the reg-
     ister number associated with the register rule.

     If	the register rule is of	type DW_EXPR_OFFSET or DW_EXPR_VAL_OFFSET, the
     location pointed to by argument offset_or_block_len will be set to	the
     offset value associated with the register rule, or	to 0 if	the register
     rule does not have	an offset value.  If the type code is
     DW_EXPR_EXPRESSION	or DW_EXPR_VAL_EXPRESSION, the location	pointed	to by
     argument offset_or_block_len will be set to the length in bytes of	the
     DWARF expression block associated with the	register rule.

     Argument block_ptr	should point to	a location which will be set to	a
     pointer to	the content of the DWARF expression block associated with the
     register rule.

     Argument row_pc should point to a location	which will be set to the low-
     est program counter address associated with the register rule found.

     If	argument err is	not NULL, it will be used to return an error descrip-
     tor in case of an error.

RETURN VALUES
     Function dwarf_get_fde_info_for_reg3() returns DW_DLV_OK when it suc-
     ceeds.  In	case of	an error, it returns DW_DLV_ERROR and sets the argu-
     ment err.

EXAMPLES
     To	retrieve the register rules at column 3	from a rule table associated
     with a FDE	descriptor:

	   Dwarf_Fde fde;
	   Dwarf_Off fde_offset, cie_offset;
	   Dwarf_Unsigned func_len, fde_length;
	   Dwarf_Signed	cie_index, offset_relevant, register_num;
	   Dwarf_Signed	offset_or_block_len;
	   Dwarf_Addr low_pc, row_pc;
	   Dwarf_Ptr fde_addr, block_ptr;
	   Dwarf_Small type;
	   Dwarf_Error de;

	   /* ... assuming `fde` references a valid FDE	descriptor... */
	   if (dwarf_get_fde_range(fde,	&low_pc, &func_len, &fde_addr,
	       &fde_length, &cie_offset, &cie_index, &fde_offset,
	       &de) != DW_DLV_OK)
		   errx(EXIT_FAILURE, "dwarf_get_fde_range failed: %s",
		       dwarf_errmsg(de));

	   /* Iterate all the table rows. */
	   for (pc = low_pc; pc	< low_pc + func_len; pc++) {
		   if (dwarf_get_fde_info_for_reg3(fde,	3, pc, &type,
		       &offset_relevant, &register_num,	&offset_or_block_len,
		       &block_ptr, &row_pc, &de) != DW_DLV_OK) {
			   warnx("dwarf_get_fde_info_for_reg3 failed: %s",
			       dwarf_errmsg(de));
			   continue;
		   }
		   /* ... use the retrieved register rule ... */
	   }

ERRORS
     Function dwarf_get_fde_info_for_reg3() can	fail with:

     [DW_DLE_ARGUMENT]		   One of the arguments	block_ptr, fde,
				   offset_or_block_len,	offset_relevant,
				   register_num, row_pc, or type was NULL.

     [DW_DLE_FRAME_TABLE_COL_BAD]  The column number provided in argument
				   table_column	was too	large.

     [DW_DLE_PC_NOT_IN_FDE_RANGE]  The program counter value provided in argu-
				   ment	pc did not fall	in the range covered
				   by argument fde.

SEE ALSO
     dwarf(3), dwarf_get_fde_at_pc(3), dwarf_get_fde_info_for_all_regs(3),
     dwarf_get_fde_info_for_all_regs3(3), dwarf_get_fde_info_for_cfa_reg3(3),
     dwarf_get_fde_info_for_reg(3), dwarf_get_fde_n(3),
     dwarf_set_frame_cfa_value(3), dwarf_set_frame_rule_initial_value(3),
     dwarf_set_frame_rule_table_size(3), dwarf_set_frame_same_value(3),
     dwarf_set_frame_undefined_value(3)

FreeBSD	13.0		       November	9, 2011			  FreeBSD 13.0

NAME | LIBRARY | SYNOPSIS | DESCRIPTION | RETURN VALUES | EXAMPLES | ERRORS | SEE ALSO

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