dwarf_get_loclist_entry(3) [freebsd man page]

DWARF_GET_LOCLIST_ENTRY(3)				   BSD Library Functions Manual 				DWARF_GET_LOCLIST_ENTRY(3)

NAME

     dwarf_get_loclist_entry -- retrieve DWARF location list entry

LIBRARY

     DWARF Access Library (libdwarf, -ldwarf)

SYNOPSIS

     #include <libdwarf.h>

     int
     dwarf_get_loclist_entry(Dwarf_Debug dbg, Dwarf_Unsigned offset, Dwarf_Addr *hipc, Dwarf_Addr *lopc, Dwarf_Ptr *data,
	 Dwarf_Unsigned *entry_len, Dwarf_Unsigned *next_entry, Dwarf_Error *err);

DESCRIPTION

     Function dwarf_get_loclist_entry() retrieves a location list entry from the DWARF section ``.debug_loc''.

     Argument dbg should reference a DWARF debug context allocated using dwarf_init(3).

     Argument offset is an offset, relative to the ``.debug_loc'' section, to the start of the desired location list entry.

     Argument hipc should point to a location which will hold the offset, relative to the base address of the location list entry, of the highest
     program counter value for the entry.

     Argument lowpc should point to a location which will hold the offset, relative to the base address of the location list entry, of the lowest
     program counter value for the entry.

     Argument data should point to a location which will be set to a pointer to the location list data.

     Argument entry_len should point to a location which will hold the length in bytes of the location list data returned in argument data.

     Argument next_entry should point to a location which will hold the offset of the next location list entry.

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

RETURN VALUES

     Function dwarf_get_loclist_entry() returns DW_DLV_OK when it succeeds.  It returns DW_DLV_NO_ENTRY if there is no location list at the speci-
     fied offset offset.  In case of an error, it returns DW_DLV_ERROR and sets the argument err.

ERRORS

     Function dwarf_get_loclist_entry() can fail with:

     [DW_DLE_ARGUMENT]	One of the arguments dbg, hipc, lopc, data, entry_len or next_entry was NULL.

     [DW_DLE_NO_ENTRY]	There is no location list at the specified offset offset.

EXAMPLE

     To iterate through all the location list entries in the ``.debug_loc'' section, use:

	   Dwarf_Debug dbg;
	   Dwarf_Unsigned off, len, next;
	   Dwarf_Addr hipc, lopc;
	   Dwarf_Ptr data;
	   Dwarf_Error de;
	   int ret;

	   off = 0;
	   while ((ret = dwarf_get_loclist_entry(dbg, off, &hipc, &lopc, &data,
	       &len, &next, &de)) == DW_DLV_OK) {
		   /* ... use loclist entry ... */
		   off = next;
	   }
	   if (ret == DW_DLV_ERROR)
		   warnx("dwarf_get_loclist_entry failed: %s", dwarf_errmsg(de));

SEE ALSO

     dwarf(3), dwarf_loclist(3), dwarf_loclist_n(3), dwarf_loclist_from_expr(3), dwarf_loclist_from_expr_a(3)

BSD
								   July 6, 2011 							       BSD

DWARF_LOCLIST_FROM_EXPR(3)				   BSD Library Functions Manual 				DWARF_LOCLIST_FROM_EXPR(3)

NAME

     dwarf_loclist_from_expr, dwarf_loclist_from_expr_a, dwarf_loclist_from_expr_b -- translate DWARF location expression bytes

LIBRARY

     DWARF Access Library (libdwarf, -ldwarf)

SYNOPSIS

     #include <libdwarf.h>

     int
     dwarf_loclist_from_expr(Dwarf_Debug dbg, Dwarf_Ptr bytes_in, Dwarf_Unsigned bytes_len, Dwarf_Locdesc **llbuf, Dwarf_Signed *listlen,
	 Dwarf_Error *err);

     int
     dwarf_loclist_from_expr_a(Dwarf_Debug dbg, Dwarf_Ptr bytes_in, Dwarf_Unsigned bytes_len, Dwarf_Half addr_size, Dwarf_Locdesc **llbuf,
	 Dwarf_Signed *listlen, Dwarf_Error *err);

     int
     dwarf_loclist_from_expr_b(Dwarf_Debug dbg, Dwarf_Ptr bytes_in, Dwarf_Unsigned bytes_len, Dwarf_Half addr_size, Dwarf_Half offset_size,
	 Dwarf_Small version, Dwarf_Locdesc **llbuf, Dwarf_Signed *listlen, Dwarf_Error *error);

DESCRIPTION

     Function dwarf_loclist_from_expr() translates DWARF location expression bytes into a Dwarf_Locdesc descriptor.  The size for address related
     data is taken to be the default address size for the object being read.

     Argument dbg should reference a DWARF debug context allocated using dwarf_init(3).

     Argument bytes_in should point to an array of DWARF location expression bytes.

     Argument bytes_len should specify the number of the location expression bytes to be translated.

     Argument llbuf should point to a location which will be set to a pointer to a returned Dwarf_Locdesc descriptor.

     Argument listlen should point to a location which will hold the number of the Dwarf_Locdesc descriptors returned.	In this case it is always
     set to 1.

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

     Function dwarf_loclist_from_expr_a() is identical to function dwarf_loclist_from_expr(), except that it requires one additional argument
     addr_size, which specifies the address size to use when translating the location expression bytes.

     Function dwarf_loclist_from_expr_b() is identical to function dwarf_loclist_from_expr_a() except that it requires two additional arguments
     for translating the location expression bytes.  Argument offset_size specifies the offset size, and argument version specifies the DWARF ver-
     sion.  These values are required to correctly translate the DW_OP_GNU_implicit_pointer opcode.

   Memory Management
     The memory area used for the descriptor returned in argument llbuf is allocated by DWARF Access Library (libdwarf, -ldwarf).  When the
     descriptor is no longer needed, application code should use function dwarf_dealloc(3) to free the memory area in two steps:
     1.   First, the array of Dwarf_Loc descriptors pointed to by the ld_s field of the Dwarf_Locdesc descriptor should be deallocated using the
	  allocation type DW_DLA_LOC_BLOCK.
     2.   Next, the application should free the llbuf pointer using the allocation type DW_DLA_LOCDESC.

RETURN VALUES

     On success, these functions returns DW_DLV_OK.  In case of an error, they return DW_DLV_ERROR and set the argument err.

ERRORS

     These functions may fail with the following errors:

     [DW_DLE_ARGUMENT]	    One of the arguments dbg, bytes_in, llbuf or listlen was NULL.

     [DW_DLE_ARGUMENT]	    Argument bytes_len was 0.

     [DW_DLE_ARGUMENT]	    The value of argument addr_size was invalid.

     [DW_DLE_LOC_EXPR_BAD]  An unknown or invalid operation was found in the location expression bytes provided in argument bytes_in.

     [DW_DLE_MEMORY]	    An out of memory condition was encountered during the execution of this function.

SEE ALSO

     dwarf(3), dwarf_dealloc(3), dwarf_loclist_n(3), dwarf_get_fde_info_for_all_regs3(3), dwarf_get_fde_info_for_cfa_reg3(3),
     dwarf_get_fde_info_for_reg3(3), dwarf_get_loclist_entry(3)

BSD
								 December 21, 2014							       BSD