1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
|
//
// GTMStackTrace.m
//
// Copyright 2007-2008 Google Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License"); you may not
// use this file except in compliance with the License. You may obtain a copy
// of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
// WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
// License for the specific language governing permissions and limitations under
// the License.
//
#include <stdlib.h>
#include <dlfcn.h>
#include <mach-o/nlist.h>
#include "GTMStackTrace.h"
#include "GTMObjC2Runtime.h"
// Structure representing a small portion of a stack, starting from the saved
// frame pointer, and continuing through the saved program counter.
struct GTMStackFrame {
void *saved_fp;
#if defined (__ppc__) || defined(__ppc64__)
void *padding;
#endif
void *saved_pc;
};
struct GTMClassDescription {
const char *class_name;
Method *class_methods;
unsigned int class_method_count;
Method *instance_methods;
unsigned int instance_method_count;
};
#pragma mark Private utility functions
static struct GTMClassDescription *GTMClassDescriptions(int *total_count) {
int class_count = objc_getClassList(nil, 0);
struct GTMClassDescription *class_descs
= calloc(class_count, sizeof(struct GTMClassDescription));
if (class_descs) {
Class *classes = calloc(class_count, sizeof(Class));
if (classes) {
objc_getClassList(classes, class_count);
for (int i = 0; i < class_count; ++i) {
class_descs[i].class_methods
= class_copyMethodList(object_getClass(classes[i]),
&class_descs[i].class_method_count);
class_descs[i].instance_methods
= class_copyMethodList(classes[i],
&class_descs[i].instance_method_count);
class_descs[i].class_name = class_getName(classes[i]);
}
free(classes);
} else {
// COV_NF_START - Don't know how to force this in a unittest
free(class_descs);
class_count = 0;
// COV_NF_END
}
}
if (total_count) {
*total_count = class_count;
}
return class_descs;
}
static void GTMFreeClassDescriptions(struct GTMClassDescription *class_descs,
int count) {
if (!class_descs || count < 0) return;
for (int i = 0; i < count; ++i) {
if (class_descs[i].instance_methods) {
free(class_descs[i].instance_methods);
}
if (class_descs[i].class_methods) {
free(class_descs[i].class_methods);
}
}
free(class_descs);
}
#pragma mark Public functions
// __builtin_frame_address(0) is a gcc builtin that returns a pointer to the
// current frame pointer. We then use the frame pointer to walk the stack
// picking off program counters and other saved frame pointers. This works
// great on i386, but PPC requires a little more work because the PC (or link
// register) isn't always stored on the stack.
//
int GTMGetStackProgramCounters(void *outPcs[], int count) {
if (!outPcs || (count < 1)) return 0;
struct GTMStackFrame *fp;
#if defined (__ppc__) || defined(__ppc64__)
outPcs[0] = __builtin_return_address(0);
fp = (struct GTMStackFrame *)__builtin_frame_address(1);
#elif defined (__i386__) || defined(__x86_64__)
fp = (struct GTMStackFrame *)__builtin_frame_address(0);
#else
#error architecture not supported
#endif
int level = 0;
while (level < count) {
if (fp == NULL) {
level--;
break;
}
outPcs[level] = fp->saved_pc;
level++;
fp = (struct GTMStackFrame *)fp->saved_fp;
}
return level;
}
int GTMGetStackAddressDescriptors(struct GTMAddressDescriptor outDescs[],
int count) {
if (count < 1) return 0;
void **pcs = calloc(count, sizeof(void*));
if (!pcs) return 0;
int newSize = GTMGetStackProgramCounters(pcs, count);
int class_desc_count;
// Get our obj-c class descriptions. This is expensive, so we do it once
// at the top. We go through this because dladdr doesn't work with
// obj methods.
struct GTMClassDescription *class_descs
= GTMClassDescriptions(&class_desc_count);
// Iterate through the stack.
for (int i = 0; i < newSize; ++i) {
const char *class_name = NULL;
Boolean is_class_method = FALSE;
size_t smallest_diff = SIZE_MAX;
struct GTMAddressDescriptor *currDesc = &outDescs[i];
currDesc->address = pcs[i];
Method best_method = NULL;
// Iterate through all the classes we know of.
for (int j = 0; j < class_desc_count; ++j) {
// First check the class methods.
for (unsigned int k = 0; k < class_descs[j].class_method_count; ++k) {
IMP imp = method_getImplementation(class_descs[j].class_methods[k]);
if (imp <= (IMP)currDesc->address) {
size_t diff = (size_t)currDesc->address - (size_t)imp;
if (diff < smallest_diff) {
best_method = class_descs[j].class_methods[k];
class_name = class_descs[j].class_name;
is_class_method = TRUE;
smallest_diff = diff;
}
}
}
// Then check the instance methods.
for (unsigned int k = 0; k < class_descs[j].instance_method_count; ++k) {
IMP imp = method_getImplementation(class_descs[j].instance_methods[k]);
if (imp <= (IMP)currDesc->address) {
size_t diff = (size_t)currDesc->address - (size_t)imp;
if (diff < smallest_diff) {
best_method = class_descs[j].instance_methods[k];
class_name = class_descs[j].class_name;
is_class_method = TRUE;
smallest_diff = diff;
}
}
}
}
// If we have one, store it off.
if (best_method) {
currDesc->symbol = sel_getName(method_getName(best_method));
currDesc->is_class_method = is_class_method;
currDesc->class_name = class_name;
}
Dl_info info = { NULL, NULL, NULL, NULL };
// Check to see if the one returned by dladdr is better.
dladdr(currDesc->address, &info);
if ((size_t)currDesc->address - (size_t)info.dli_saddr < smallest_diff) {
currDesc->symbol = info.dli_sname;
currDesc->is_class_method = FALSE;
currDesc->class_name = NULL;
}
currDesc->filename = info.dli_fname;
}
GTMFreeClassDescriptions(class_descs, class_desc_count);
return newSize;
}
NSString *GTMStackTrace(void) {
// The maximum number of stack frames that we will walk. We limit this so
// that super-duper recursive functions (or bugs) don't send us for an
// infinite loop.
const int kMaxStackTraceDepth = 100;
struct GTMAddressDescriptor descs[kMaxStackTraceDepth];
int depth = kMaxStackTraceDepth;
depth = GTMGetStackAddressDescriptors(descs, depth);
NSMutableString *trace = [NSMutableString string];
// Start at the second item so that GTMStackTrace and it's utility calls (of
// which there is currently 1) is not included in the output.
const int kTracesToStrip = 2;
for (int i = kTracesToStrip; i < depth; i++) {
if (descs[i].class_name) {
[trace appendFormat:@"#%-2d 0x%08lx %s[%s %s] (%s)\n",
i - kTracesToStrip, descs[i].address,
(descs[i].is_class_method ? "+" : "-"),
descs[i].class_name,
(descs[i].symbol ? descs[i].symbol : "??"),
(descs[i].filename ? descs[i].filename : "??")];
} else {
[trace appendFormat:@"#%-2d 0x%08lx %s() (%s)\n",
i - kTracesToStrip, descs[i].address,
(descs[i].symbol ? descs[i].symbol : "??"),
(descs[i].filename ? descs[i].filename : "??")];
}
}
return trace;
}
|
