lib/coverage.h

   1 /*
   2  * Copyright (c) 2009, 2010, 2011, 2012 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 "vlog.h"
  31
  32 /* A coverage counter. */
  33 struct coverage_counter {
  34     const char *name;           /* Textual name. */
  35     unsigned int count;         /* Count within the current epoch. */
  36     unsigned long long int total; /* Total count over all epochs. */
  37 };
  38
  39 /* Defines COUNTER.  There must be exactly one such definition at file scope
  40  * within a program. */
  41 #if USE_LINKER_SECTIONS
  42 #define COVERAGE_DEFINE(COUNTER)                                        \
  43         COVERAGE_DEFINE__(COUNTER);                                     \
  44         extern struct coverage_counter *counter_ptr_##COUNTER;          \
  45         struct coverage_counter *counter_ptr_##COUNTER                  \
  46             __attribute__((section("coverage"))) = &counter_##COUNTER
  47 #else
  48 #define COVERAGE_DEFINE(MODULE) \
  49         extern struct coverage_counter counter_##MODULE
  50 #endif
  51
  52 /* Adds 1 to COUNTER. */
  53 #define COVERAGE_INC(COUNTER) counter_##COUNTER.count++;
  54
  55 /* Adds AMOUNT to COUNTER. */
  56 #define COVERAGE_ADD(COUNTER, AMOUNT) counter_##COUNTER.count += (AMOUNT);
  57
  58 void coverage_init(void);
  59 void coverage_log(void);
  60 void coverage_clear(void);
  61
  62 /* Implementation detail. */
  63 #define COVERAGE_DEFINE__(COUNTER)                              \
  64         extern struct coverage_counter counter_##COUNTER;       \
  65         struct coverage_counter counter_##COUNTER = { #COUNTER, 0, 0 }
  66
  67 #endif /* coverage.h */