xref: /freebsd/contrib/elftoolchain/libdwarf/dwarf_add_AT_location_expr.3 (revision 5ca8e32633c4ffbbcd6762e5888b6a4ba0708c6c)
1.\" Copyright (c) 2011 Kai Wang
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25.\" $Id: dwarf_add_AT_location_expr.3 3640 2018-10-14 14:09:13Z jkoshy $
26.\"
27.Dd September 5, 2011
28.Dt DWARF_ADD_AT_LOCATION_EXPR 3
29.Os
30.Sh NAME
31.Nm dwarf_add_AT_location_expr
32.Nd create an attribute descriptor for a location expression
33.Sh LIBRARY
34.Lb libdwarf
35.Sh SYNOPSIS
36.In libdwarf.h
37.Ft "Dwarf_P_Attribute"
38.Fo dwarf_add_AT_location_expr
39.Fa "Dwarf_P_Debug dbg"
40.Fa "Dwarf_P_Die die"
41.Fa "Dwarf_Half attr"
42.Fa "Dwarf_P_Expr loc_expr"
43.Fa "Dwarf_Error *err"
44.Fc
45.Sh DESCRIPTION
46Function
47.Fn dwarf_add_AT_location_expr
48creates an attribute descriptor for a location expression and attaches
49it to the debugging information entry referenced by argument
50.Ar die .
51.Pp
52Argument
53.Ar dbg
54should reference a DWARF producer instance allocated using
55.Xr dwarf_producer_init 3
56or
57.Xr dwarf_producer_init_b 3 .
58.Pp
59Argument
60.Ar die
61should reference a debugging information entry allocated using
62.Xr dwarf_new_die 3 .
63.Pp
64Argument
65.Ar attr
66specifies the attribute code of the created attribute descriptor.
67.Pp
68Argument
69.Ar loc_expr
70should reference a location expression descriptor allocated using
71.Xr dwarf_new_expr 3 .
72.Pp
73The attribute created by function
74.Fn dwarf_add_AT_location_expr
75will have one of the DWARF forms
76.Dv DW_FORM_block ,
77.Dv DW_FORM_block1 ,
78.Dv DW_FORM_block2
79or
80.Dv DW_FORM_block4 ,
81depending on the size of the byte stream generated by the location
82expression descriptor referenced by argument
83.Ar loc_expr .
84.Pp
85If argument
86.Ar err
87is not NULL, it will be used by to store error information in case of
88an error.
89.Sh RETURN VALUES
90On success, function
91.Fn dwarf_add_AT_location_expr
92returns the created attribute descriptor.
93In case of an error, function
94.Fn dwarf_add_AT_location_expr
95returns
96.Dv DW_DLV_BADADDR
97and sets the argument
98.Ar err .
99.Sh ERRORS
100Function
101.Fn dwarf_add_AT_location_expr
102can fail with:
103.Bl -tag -width ".Bq Er DW_DLE_ARGUMENT"
104.It Bq Er DW_DLE_ARGUMENT
105One of the arguments
106.Ar dbg ,
107.Ar die
108or
109.Ar loc_expr
110was NULL.
111.It Bq Er DW_DLE_MEMORY
112An out of memory condition was encountered during the execution of the
113function.
114.El
115.Sh SEE ALSO
116.Xr dwarf 3 ,
117.Xr dwarf_new_die 3 ,
118.Xr dwarf_new_expr 3 ,
119.Xr dwarf_producer_init 3 ,
120.Xr dwarf_producer_init_b 3
121