xref: /freebsd/contrib/elftoolchain/libdwarf/dwarf_add_AT_location_expr.3 (revision 8ddb146abcdf061be9f2c0db7e391697dafad85c)
1.\" Copyright (c) 2011 Kai Wang
2.\" All rights reserved.
3.\"
4.\" Redistribution and use in source and binary forms, with or without
5.\" modification, are permitted provided that the following conditions
6.\" are met:
7.\" 1. Redistributions of source code must retain the above copyright
8.\"    notice, this list of conditions and the following disclaimer.
9.\" 2. Redistributions in binary form must reproduce the above copyright
10.\"    notice, this list of conditions and the following disclaimer in the
11.\"    documentation and/or other materials provided with the distribution.
12.\"
13.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
14.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
16.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
17.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
18.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
19.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
20.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
21.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
22.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
23.\" SUCH DAMAGE.
24.\"
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