source: rtems-tools/rtemstoolkit/elftoolchain/libdwarf/dwarf_get_fde_info_for_reg3.3 @ 4bb3996

5
Last change on this file since 4bb3996 was 4bb3996, checked in by Chris Johns <chrisj@…>, on 04/30/18 at 05:34:48

rtemstoolkit: Add libdwarf from elftoolchain.

The code is taken from:

https://svn.code.sf.net/p/elftoolchain/code/trunk

Update #3417

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1.\" Copyright (c) 2011 Kai Wang
2.\" All rights reserved.
3.\"
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25.\" $Id: dwarf_get_fde_info_for_reg3.3 2122 2011-11-09 15:35:14Z jkoshy $
26.\"
27.Dd November 9, 2011
28.Os
29.Dt DWARF_GET_FDE_INFO_FOR_REG3 3
30.Sh NAME
31.Nm dwarf_get_fde_info_for_reg3
32.Nd retrieve register rule
33.Sh LIBRARY
34.Lb libdwarf
35.Sh SYNOPSIS
36.In libdwarf.h
37.Ft int
38.Fo dwarf_get_fde_info_for_reg3
39.Fa "Dwarf_Fde fde"
40.Fa "Dwarf_Half table_column"
41.Fa "Dwarf_Addr pc"
42.Fa "Dwarf_Small *type"
43.Fa "Dwarf_Signed *offset_relevant"
44.Fa "Dwarf_Signed *register_num"
45.Fa "Dwarf_Signed *offset_or_block_len"
46.Fa "Dwarf_Ptr *block_ptr"
47.Fa "Dwarf_Addr *row_pc"
48.Fa "Dwarf_Error *error"
49.Fc
50.Sh DESCRIPTION
51Function
52.Fn dwarf_get_fde_info_for_reg3
53retrieves a register rule from the register rule table associated with
54a given FDE descriptor, given a program counter address and rule
55column number.
56.Pp
57Argument
58.Ar fde
59should reference a valid DWARF FDE descriptor.
60.Pp
61Arugment
62.Ar table_column
63should hold the column number of the register rule desired.
64.Pp
65Argument
66.Ar pc
67should hold the program counter address to be used to locate the
68desired register rule row.
69.Pp
70On successful execution,
71.Fn dwarf_get_fde_info_for_reg3
72stores information about the register rule found into the locations
73pointed to by the arguments
74.Ar type ,
75.Ar offset_relevant ,
76.Ar register_num ,
77.Ar offset_or_block_len ,
78.Ar block_ptr
79and
80.Ar row_pc .
81.Pp
82Argument
83.Ar type
84should point to a location which will hold the type code of the
85register rule found.
86The returned value is one of the
87.Dv DW_EXPR_*
88contants defined in the header file
89.In libdwarf.h .
90.Pp
91If there is an offset value associated with the register rule,
92the location pointed to by argument
93.Ar offset_relevant
94will be set to 1.
95.Pp
96Argument
97.Ar register_num
98should point to a location which will hold the register number associated
99with the register rule.
100.Pp
101If the register rule is of type
102.Dv DW_EXPR_OFFSET
103or
104.Dv DW_EXPR_VAL_OFFSET ,
105the location pointed to by argument
106.Ar offset_or_block_len
107will be set to the offset value associated with the register rule,
108or to 0 if the register rule does not have an offset value.
109If the type code is
110.Dv DW_EXPR_EXPRESSION
111or
112.Dv DW_EXPR_VAL_EXPRESSION ,
113the location pointed to by argument
114.Ar offset_or_block_len
115will be set to the length in bytes of the DWARF expression block
116associated with the register rule.
117.Pp
118Argument
119.Ar block_ptr
120should point to a location which will be set to a pointer to the
121content of the DWARF expression block associated with the register
122rule.
123.Pp
124Argument
125.Ar row_pc
126should point to a location which will be set to the lowest program
127counter address associated with the register rule found.
128.Pp
129If argument
130.Ar err
131is not NULL, it will be used to return an error descriptor in case
132of an error.
133.Sh RETURN VALUES
134Function
135.Fn dwarf_get_fde_info_for_reg3
136returns
137.Dv DW_DLV_OK
138when it succeeds.
139In case of an error, it returns
140.Dv DW_DLV_ERROR
141and sets the argument
142.Ar err .
143.Sh ERRORS
144Function
145.Fn dwarf_get_fde_info_for_reg3
146can fail with:
147.Bl -tag -width ".Bq Er DW_DLE_FRAME_TABLE_COL_BAD"
148.It Bq Er DW_DLE_ARGUMENT
149One of the arguments
150.Ar block_ptr ,
151.Ar fde ,
152.Ar offset_or_block_len ,
153.Ar offset_relevant ,
154.Ar register_num ,
155.Ar row_pc ,
156or
157.Ar type
158was NULL.
159.It Bq Er DW_DLE_FRAME_TABLE_COL_BAD
160The column number provided in argument
161.Ar table_column
162was too large.
163.It Bq Er DW_DLE_PC_NOT_IN_FDE_RANGE
164The program counter value provided in argument
165.Ar pc
166did not fall in the range covered by argument
167.Ar fde .
168.El
169.Sh EXAMPLE
170To retrieve the register rules at column 3 from a rule table
171associated with a FDE descriptor:
172.Bd -literal -offset indent
173Dwarf_Fde fde;
174Dwarf_Off fde_offset, cie_offset;
175Dwarf_Unsigned func_len, fde_length;
176Dwarf_Signed cie_index, offset_relevant, register_num;
177Dwarf_Signed offset_or_block_len;
178Dwarf_Addr low_pc, row_pc;
179Dwarf_Ptr fde_addr, block_ptr;
180Dwarf_Small type;
181Dwarf_Error de;
182
183/* ... assuming `fde` references a valid FDE descriptor... */
184if (dwarf_get_fde_range(fde, &low_pc, &func_len, &fde_addr,
185    &fde_length, &cie_offset, &cie_index, &fde_offset,
186    &de) != DW_DLV_OK)
187        errx(EXIT_FAILURE, "dwarf_get_fde_range failed: %s",
188            dwarf_errmsg(de));
189
190/* Iterate all the table rows. */
191for (pc = low_pc; pc < low_pc + func_len; pc++) {
192        if (dwarf_get_fde_info_for_reg3(fde, 3, pc, &type,
193            &offset_relevant, &register_num, &offset_or_block_len,
194            &block_ptr, &row_pc, &de) != DW_DLV_OK) {
195                warnx("dwarf_get_fde_info_for_reg3 failed: %s",
196                    dwarf_errmsg(de));
197                continue;
198        }
199        /* ... use the retrieved register rule ... */
200}
201.Ed
202.Sh SEE ALSO
203.Xr dwarf 3 ,
204.Xr dwarf_get_fde_at_pc 3 ,
205.Xr dwarf_get_fde_info_for_all_regs 3 ,
206.Xr dwarf_get_fde_info_for_all_regs3 3 ,
207.Xr dwarf_get_fde_info_for_cfa_reg3 3 ,
208.Xr dwarf_get_fde_info_for_reg 3 ,
209.Xr dwarf_get_fde_n 3 ,
210.Xr dwarf_set_frame_cfa_value 3 ,
211.Xr dwarf_set_frame_rule_table_size 3 ,
212.Xr dwarf_set_frame_rule_initial_value 3 ,
213.Xr dwarf_set_frame_same_value 3 ,
214.Xr dwarf_set_frame_undefined_value 3
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