1 /* Find entry breakpoint locations for a function.
2 Copyright (C) 2005-2009 Red Hat, Inc.
3 This file is part of elfutils.
4
5 This file is free software; you can redistribute it and/or modify
6 it under the terms of either
7
8 * the GNU Lesser General Public License as published by the Free
9 Software Foundation; either version 3 of the License, or (at
10 your option) any later version
11
12 or
13
14 * the GNU General Public License as published by the Free
15 Software Foundation; either version 2 of the License, or (at
16 your option) any later version
17
18 or both in parallel, as here.
19
20 elfutils is distributed in the hope that it will be useful, but
21 WITHOUT ANY WARRANTY; without even the implied warranty of
22 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
23 General Public License for more details.
24
25 You should have received copies of the GNU General Public License and
26 the GNU Lesser General Public License along with this program. If
27 not, see <http://www.gnu.org/licenses/>. */
28
29 #ifdef HAVE_CONFIG_H
30 # include <config.h>
31 #endif
32 #include "libdwP.h"
33 #include <dwarf.h>
34 #include <stdlib.h>
35
36
37 /* Add one breakpoint location to the result vector. */
38 static inline int
add_bkpt(Dwarf_Addr pc,Dwarf_Addr ** bkpts,int * pnbkpts)39 add_bkpt (Dwarf_Addr pc, Dwarf_Addr **bkpts, int *pnbkpts)
40 {
41 Dwarf_Addr *newlist = realloc (*bkpts, ++(*pnbkpts) * sizeof newlist[0]);
42 if (newlist == NULL)
43 {
44 free (*bkpts);
45 *bkpts = NULL;
46 __libdw_seterrno (DWARF_E_NOMEM);
47 return -1;
48 }
49 newlist[*pnbkpts - 1] = pc;
50 *bkpts = newlist;
51 return *pnbkpts;
52 }
53
54 /* Fallback result, break at the entrypc/lowpc value. */
55 static inline int
entrypc_bkpt(Dwarf_Die * die,Dwarf_Addr ** bkpts,int * pnbkpts)56 entrypc_bkpt (Dwarf_Die *die, Dwarf_Addr **bkpts, int *pnbkpts)
57 {
58 Dwarf_Addr pc;
59 return INTUSE(dwarf_entrypc) (die, &pc) < 0 ? -1 : add_bkpt (pc, bkpts, pnbkpts);
60 }
61
62 /* Search a contiguous PC range for prologue-end markers.
63 If DWARF, look for proper markers.
64 Failing that, if ADHOC, look for the ad hoc convention. */
65 static inline int
search_range(Dwarf_Addr low,Dwarf_Addr high,bool dwarf,bool adhoc,Dwarf_Lines * lines,size_t nlines,Dwarf_Addr ** bkpts,int * pnbkpts)66 search_range (Dwarf_Addr low, Dwarf_Addr high,
67 bool dwarf, bool adhoc,
68 Dwarf_Lines *lines, size_t nlines,
69 Dwarf_Addr **bkpts, int *pnbkpts)
70 {
71 size_t l = 0, u = nlines;
72 while (l < u)
73 {
74 size_t idx = (l + u) / 2;
75 if (lines->info[idx].addr < low)
76 l = idx + 1;
77 else if (lines->info[idx].addr > low)
78 u = idx;
79 else if (lines->info[idx].end_sequence)
80 l = idx + 1;
81 else
82 {
83 l = idx;
84 break;
85 }
86 }
87 if (l < u)
88 {
89 if (dwarf)
90 for (size_t i = l; i < u && lines->info[i].addr < high; ++i)
91 if (lines->info[i].prologue_end
92 && add_bkpt (lines->info[i].addr, bkpts, pnbkpts) < 0)
93 return -1;
94 if (adhoc && *pnbkpts == 0)
95 while (++l < nlines && lines->info[l].addr < high)
96 if (!lines->info[l].end_sequence)
97 return add_bkpt (lines->info[l].addr, bkpts, pnbkpts);
98 return *pnbkpts;
99 }
100 __libdw_seterrno (DWARF_E_INVALID_DWARF);
101 return -1;
102 }
103
104 int
dwarf_entry_breakpoints(Dwarf_Die * die,Dwarf_Addr ** bkpts)105 dwarf_entry_breakpoints (Dwarf_Die *die, Dwarf_Addr **bkpts)
106 {
107 int nbkpts = 0;
108 *bkpts = NULL;
109
110 /* Fetch the CU's line records to look for this DIE's addresses. */
111 Dwarf_Die cudie = CUDIE (die->cu);
112 Dwarf_Lines *lines;
113 size_t nlines;
114 if (INTUSE(dwarf_getsrclines) (&cudie, &lines, &nlines) < 0)
115 {
116 int error = INTUSE (dwarf_errno) ();
117 if (error == 0) /* CU has no DW_AT_stmt_list. */
118 return entrypc_bkpt (die, bkpts, &nbkpts);
119 __libdw_seterrno (error);
120 return -1;
121 }
122
123 /* Search each contiguous address range for DWARF prologue_end markers. */
124
125 Dwarf_Addr base;
126 Dwarf_Addr begin;
127 Dwarf_Addr end;
128 ptrdiff_t offset = INTUSE(dwarf_ranges) (die, 0, &base, &begin, &end);
129 if (offset < 0)
130 return -1;
131
132 /* Most often there is a single contiguous PC range for the DIE. */
133 if (offset == 1)
134 return search_range (begin, end, true, true, lines, nlines, bkpts, &nbkpts)
135 ?: entrypc_bkpt (die, bkpts, &nbkpts);
136
137 Dwarf_Addr lowpc = (Dwarf_Addr) -1l;
138 Dwarf_Addr highpc = (Dwarf_Addr) -1l;
139 while (offset > 0)
140 {
141 /* We have an address range entry. */
142 if (search_range (begin, end, true, false,
143 lines, nlines, bkpts, &nbkpts) < 0)
144 return -1;
145
146 if (begin < lowpc)
147 {
148 lowpc = begin;
149 highpc = end;
150 }
151
152 offset = INTUSE(dwarf_ranges) (die, offset, &base, &begin, &end);
153 }
154
155 /* If we didn't find any proper DWARF markers, then look in the
156 lowest-addressed range for an ad hoc marker. Failing that,
157 fall back to just using the entrypc value. */
158 return (nbkpts
159 ?: (lowpc == (Dwarf_Addr) -1l ? 0
160 : search_range (lowpc, highpc, false, true,
161 lines, nlines, bkpts, &nbkpts))
162 ?: entrypc_bkpt (die, bkpts, &nbkpts));
163 }
164