lib/coverage.h

   1 /*
   2  * Copyright (c) 2009, 2010, 2011, 2012, 2013 Nicira, Inc.
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the "License");
   5  * you may not use this file except in compliance with the License.
   6  * You may obtain a copy of the License at:
   7  *
   8  *     http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  */
  16
  17 #ifndef COVERAGE_H
  18 #define COVERAGE_H 1
  19
  20 /* This file implements a simple form of coverage instrumentation.  Points in
  21  * source code that are of interest must be explicitly annotated with
  22  * COVERAGE_INC.  The coverage counters may be logged at any time with
  23  * coverage_log().
  24  *
  25  * This form of coverage instrumentation is intended to be so lightweight that
  26  * it can be enabled in production builds.  It is obviously not a substitute
  27  * for traditional coverage instrumentation with e.g. "gcov", but it is still
  28  * a useful debugging tool. */
  29
  30 #include "ovs-thread.h"
  31 #include "vlog.h"
  32
  33 /* A coverage counter. */
  34 struct coverage_counter {
  35     const char *const name;            /* Textual name. */
  36     unsigned int (*const count)(void); /* Gets, zeros this thread's count. */
  37     unsigned long long int total;      /* Total count. */
  38 };
  39
  40 /* Defines COUNTER.  There must be exactly one such definition at file scope
  41  * within a program. */
  42 #if USE_LINKER_SECTIONS
  43 #define COVERAGE_DEFINE(COUNTER)                                        \
  44         DEFINE_STATIC_PER_THREAD_DATA(unsigned int,                     \
  45                                       counter_##COUNTER, 0);            \
  46         static unsigned int COUNTER##_count(void)                       \
  47         {                                                               \
  48             unsigned int *countp = counter_##COUNTER##_get();           \
  49             unsigned int count = *countp;                               \
  50             *countp = 0;                                                \
  51             return count;                                               \
  52         }                                                               \
  53         static inline void COUNTER##_add(unsigned int n)                \
  54         {                                                               \
  55             *counter_##COUNTER##_get() += n;                            \
  56         }                                                               \
  57         extern struct coverage_counter counter_##COUNTER;               \
  58         struct coverage_counter counter_##COUNTER                       \
  59             = { #COUNTER, COUNTER##_count, 0 };                         \
  60         extern struct coverage_counter *counter_ptr_##COUNTER;          \
  61         struct coverage_counter *counter_ptr_##COUNTER                  \
  62             __attribute__((section("coverage"))) = &counter_##COUNTER
  63 #else
  64 #define COVERAGE_DEFINE(COUNTER)                                        \
  65         DECLARE_EXTERN_PER_THREAD_DATA(unsigned int,                    \
  66                                        counter_##COUNTER);              \
  67         static inline void COUNTER##_add(unsigned int n)                \
  68         {                                                               \
  69             *counter_##COUNTER##_get() += n;                            \
  70         }                                                               \
  71         extern struct coverage_counter counter_##COUNTER
  72 #endif
  73
  74 /* Adds 1 to COUNTER. */
  75 #define COVERAGE_INC(COUNTER) COVERAGE_ADD(COUNTER, 1)
  76
  77 /* Adds AMOUNT to COUNTER. */
  78 #define COVERAGE_ADD(COUNTER, AMOUNT) COUNTER##_add(AMOUNT)
  79
  80 void coverage_init(void);
  81 void coverage_log(void);
  82 void coverage_clear(void);
  83
  84 /* Implementation detail. */
  85 #define COVERAGE_DEFINE__(COUNTER)                              \
  86
  87 #endif /* coverage.h */