File: symbolize_unittest.cc

package info (click to toggle)
autofdo 0.18-2
  • links: PTS
  • area: main
  • in suites: bullseye, buster, sid
  • size: 92,568 kB
  • sloc: cpp: 26,830; sh: 12,538; makefile: 344; ansic: 134; python: 95
file content (365 lines) | stat: -rw-r--r-- 11,701 bytes parent folder | download | duplicates (23)
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
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
// Copyright (c) 2006, Google Inc.
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
//     * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
//     * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
//     * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
//
// Author: Satoru Takabayashi
//
// Unit tests for functions in symbolize.cc.

#include "utilities.h"

#include <signal.h>
#include <iostream>

#include "glog/logging.h"
#include "symbolize.h"
#include "googletest.h"
#include "config.h"

using namespace std;
using namespace GOOGLE_NAMESPACE;

#if defined(HAVE_STACKTRACE) && defined(__ELF__)

#define always_inline

// This unit tests make sense only with GCC.
// Uses lots of GCC specific features.
#if defined(__GNUC__) && !defined(__OPENCC__)
#  if __GNUC__ >= 4
#    define TEST_WITH_MODERN_GCC
#    if __i386__  // always_inline isn't supported for x86_64 with GCC 4.1.0.
#      undef always_inline
#      define always_inline __attribute__((always_inline))
#      define HAVE_ALWAYS_INLINE
#    endif  // __i386__
#  else
#  endif  // __GNUC__ >= 4
#  if defined(__i386__) || defined(__x86_64__)
#    define TEST_X86_32_AND_64 1
#  endif  // defined(__i386__) || defined(__x86_64__)
#endif

// A wrapper function for Symbolize() to make the unit test simple.
static const char *TrySymbolize(void *pc) {
  static char symbol[4096];
  if (Symbolize(pc, symbol, sizeof(symbol))) {
    return symbol;
  } else {
    return NULL;
  }
}

// Make them C linkage to avoid mangled names.
extern "C" {
void nonstatic_func() {
  volatile int a = 0;
  ++a;
}

static void static_func() {
  volatile int a = 0;
  ++a;
}
}

TEST(Symbolize, Symbolize) {
  // We do C-style cast since GCC 2.95.3 doesn't allow
  // reinterpret_cast<void *>(&func).

  // Compilers should give us pointers to them.
  EXPECT_STREQ("nonstatic_func", TrySymbolize((void *)(&nonstatic_func)));
  EXPECT_STREQ("static_func", TrySymbolize((void *)(&static_func)));

  EXPECT_TRUE(NULL == TrySymbolize(NULL));
}

struct Foo {
  static void func(int x);
};

void ATTRIBUTE_NOINLINE Foo::func(int x) {
  volatile int a = x;
  ++a;
}

// With a modern GCC, Symbolize() should return demangled symbol
// names.  Function parameters should be omitted.
#ifdef TEST_WITH_MODERN_GCC
TEST(Symbolize, SymbolizeWithDemangling) {
  Foo::func(100);
  EXPECT_STREQ("Foo::func()", TrySymbolize((void *)(&Foo::func)));
}
#endif

// Tests that verify that Symbolize footprint is within some limit.

// To measure the stack footprint of the Symbolize function, we create
// a signal handler (for SIGUSR1 say) that calls the Symbolize function
// on an alternate stack. This alternate stack is initialized to some
// known pattern (0x55, 0x55, 0x55, ...). We then self-send this signal,
// and after the signal handler returns, look at the alternate stack
// buffer to see what portion has been touched.
//
// This trick gives us the the stack footprint of the signal handler.
// But the signal handler, even before the call to Symbolize, consumes
// some stack already. We however only want the stack usage of the
// Symbolize function. To measure this accurately, we install two signal
// handlers: one that does nothing and just returns, and another that
// calls Symbolize. The difference between the stack consumption of these
// two signals handlers should give us the Symbolize stack foorprint.

static void *g_pc_to_symbolize;
static char g_symbolize_buffer[4096];
static char *g_symbolize_result;

static void EmptySignalHandler(int signo) {}

static void SymbolizeSignalHandler(int signo) {
  if (Symbolize(g_pc_to_symbolize, g_symbolize_buffer,
                sizeof(g_symbolize_buffer))) {
    g_symbolize_result = g_symbolize_buffer;
  } else {
    g_symbolize_result = NULL;
  }
}

const int kAlternateStackSize = 8096;
const char kAlternateStackFillValue = 0x55;

// These helper functions look at the alternate stack buffer, and figure
// out what portion of this buffer has been touched - this is the stack
// consumption of the signal handler running on this alternate stack.
static ATTRIBUTE_NOINLINE bool StackGrowsDown(int *x) {
  int y;
  return &y < x;
}
static int GetStackConsumption(const char* alt_stack) {
  int x;
  if (StackGrowsDown(&x)) {
    for (int i = 0; i < kAlternateStackSize; i++) {
      if (alt_stack[i] != kAlternateStackFillValue) {
        return (kAlternateStackSize - i);
      }
    }
  } else {
    for (int i = (kAlternateStackSize - 1); i >= 0; i--) {
      if (alt_stack[i] != kAlternateStackFillValue) {
        return i;
      }
    }
  }
  return -1;
}

#ifdef HAVE_SIGALTSTACK

// Call Symbolize and figure out the stack footprint of this call.
static const char *SymbolizeStackConsumption(void *pc, int *stack_consumed) {

  g_pc_to_symbolize = pc;

  // The alt-signal-stack cannot be heap allocated because there is a
  // bug in glibc-2.2 where some signal handler setup code looks at the
  // current stack pointer to figure out what thread is currently running.
  // Therefore, the alternate stack must be allocated from the main stack
  // itself.
  char altstack[kAlternateStackSize];
  memset(altstack, kAlternateStackFillValue, kAlternateStackSize);

  // Set up the alt-signal-stack (and save the older one).
  stack_t sigstk;
  memset(&sigstk, 0, sizeof(stack_t));
  stack_t old_sigstk;
  sigstk.ss_sp = altstack;
  sigstk.ss_size = kAlternateStackSize;
  sigstk.ss_flags = 0;
  CHECK_ERR(sigaltstack(&sigstk, &old_sigstk));

  // Set up SIGUSR1 and SIGUSR2 signal handlers (and save the older ones).
  struct sigaction sa;
  memset(&sa, 0, sizeof(struct sigaction));
  struct sigaction old_sa1, old_sa2;
  sigemptyset(&sa.sa_mask);
  sa.sa_flags = SA_ONSTACK;

  // SIGUSR1 maps to EmptySignalHandler.
  sa.sa_handler = EmptySignalHandler;
  CHECK_ERR(sigaction(SIGUSR1, &sa, &old_sa1));

  // SIGUSR2 maps to SymbolizeSignalHanlder.
  sa.sa_handler = SymbolizeSignalHandler;
  CHECK_ERR(sigaction(SIGUSR2, &sa, &old_sa2));

  // Send SIGUSR1 signal and measure the stack consumption of the empty
  // signal handler.
  CHECK_ERR(kill(getpid(), SIGUSR1));
  int stack_consumption1 = GetStackConsumption(altstack);

  // Send SIGUSR2 signal and measure the stack consumption of the symbolize
  // signal handler.
  CHECK_ERR(kill(getpid(), SIGUSR2));
  int stack_consumption2 = GetStackConsumption(altstack);

  // The difference between the two stack consumption values is the
  // stack footprint of the Symbolize function.
  if (stack_consumption1 != -1 && stack_consumption2 != -1) {
    *stack_consumed = stack_consumption2 - stack_consumption1;
  } else {
    *stack_consumed = -1;
  }

  // Log the stack consumption values.
  LOG(INFO) << "Stack consumption of empty signal handler: "
            << stack_consumption1;
  LOG(INFO) << "Stack consumption of symbolize signal handler: "
            << stack_consumption2;
  LOG(INFO) << "Stack consumption of Symbolize: " << *stack_consumed;

  // Now restore the old alt-signal-stack and signal handlers.
  CHECK_ERR(sigaltstack(&old_sigstk, NULL));
  CHECK_ERR(sigaction(SIGUSR1, &old_sa1, NULL));
  CHECK_ERR(sigaction(SIGUSR2, &old_sa2, NULL));

  return g_symbolize_result;
}

// Symbolize stack consumption should be within 2kB.
const int kStackConsumptionUpperLimit = 2048;

TEST(Symbolize, SymbolizeStackConsumption) {
  int stack_consumed;
  const char* symbol;

  symbol = SymbolizeStackConsumption((void *)(&nonstatic_func),
                                     &stack_consumed);
  EXPECT_STREQ("nonstatic_func", symbol);
  EXPECT_GT(stack_consumed, 0);
  EXPECT_LT(stack_consumed, kStackConsumptionUpperLimit);

  symbol = SymbolizeStackConsumption((void *)(&static_func),
                                     &stack_consumed);
  EXPECT_STREQ("static_func", symbol);
  EXPECT_GT(stack_consumed, 0);
  EXPECT_LT(stack_consumed, kStackConsumptionUpperLimit);
}

#ifdef TEST_WITH_MODERN_GCC
TEST(Symbolize, SymbolizeWithDemanglingStackConsumption) {
  Foo::func(100);
  int stack_consumed;
  const char* symbol;

  symbol = SymbolizeStackConsumption((void *)(&Foo::func), &stack_consumed);

  EXPECT_STREQ("Foo::func()", symbol);
  EXPECT_GT(stack_consumed, 0);
  EXPECT_LT(stack_consumed, kStackConsumptionUpperLimit);
}
#endif

#endif  // HAVE_SIGALTSTACK

// x86 specific tests.  Uses some inline assembler.
extern "C" {
inline void* always_inline inline_func() {
  register void *pc = NULL;
#ifdef TEST_X86_32_AND_64
  __asm__ __volatile__("call 1f; 1: pop %0" : "=r"(pc));
#endif
  return pc;
}

void* ATTRIBUTE_NOINLINE non_inline_func() {
  register void *pc = NULL;
#ifdef TEST_X86_32_AND_64
  __asm__ __volatile__("call 1f; 1: pop %0" : "=r"(pc));
#endif
  return pc;
}

void ATTRIBUTE_NOINLINE TestWithPCInsideNonInlineFunction() {
#if defined(TEST_X86_32_AND_64) && defined(HAVE_ATTRIBUTE_NOINLINE)
  void *pc = non_inline_func();
  const char *symbol = TrySymbolize(pc);
  CHECK(symbol != NULL);
  CHECK_STREQ(symbol, "non_inline_func");
  cout << "Test case TestWithPCInsideNonInlineFunction passed." << endl;
#endif
}

void ATTRIBUTE_NOINLINE TestWithPCInsideInlineFunction() {
#if defined(TEST_X86_32_AND_64) && defined(HAVE_ALWAYS_INLINE)
  void *pc = inline_func();  // Must be inlined.
  const char *symbol = TrySymbolize(pc);
  CHECK(symbol != NULL);
  CHECK_STREQ(symbol, __FUNCTION__);
  cout << "Test case TestWithPCInsideInlineFunction passed." << endl;
#endif
}
}

// Test with a return address.
void ATTRIBUTE_NOINLINE TestWithReturnAddress() {
#if defined(HAVE_ATTRIBUTE_NOINLINE)
  void *return_address = __builtin_return_address(0);
  const char *symbol = TrySymbolize(return_address);
  CHECK(symbol != NULL);
  CHECK_STREQ(symbol, "main");
  cout << "Test case TestWithReturnAddress passed." << endl;
#endif
}

int main(int argc, char **argv) {
  FLAGS_logtostderr = true;
  InitGoogleLogging(argv[0]);
  InitGoogleTest(&argc, argv);
#ifdef HAVE_SYMBOLIZE
  // We don't want to get affected by the callback interface, that may be
  // used to install some callback function at InitGoogle() time.
  InstallSymbolizeCallback(NULL);

  TestWithPCInsideInlineFunction();
  TestWithPCInsideNonInlineFunction();
  TestWithReturnAddress();
  return RUN_ALL_TESTS();
#else
  return 0;
#endif
}

#else
int main() {
#ifdef HAVE_SYMBOLIZE
  printf("PASS (no symbolize_unittest support)\n");
#else
  printf("PASS (no symbolize support)\n");
#endif
  return 0;
}
#endif  // HAVE_STACKTRACE