1 files changed, 168 insertions, 0 deletions
diff --git a/libdimension/base/profile.c b/libdimension/base/profile.c
new file mode 100644
index 0000000..87f27c1
--- /dev/null
+++ b/libdimension/base/profile.c
@@ -0,0 +1,168 @@
+/*************************************************************************
+ * Copyright (C) 2010-2011 Tavian Barnes <tavianator@tavianator.com>     *
+ *                                                                       *
+ * This file is part of The Dimension Library.                           *
+ *                                                                       *
+ * The Dimension Library is free software; you can redistribute it and/  *
+ * or modify it under the terms of the GNU Lesser General Public License *
+ * as published by the Free Software Foundation; either version 3 of the *
+ * License, or (at your option) any later version.                       *
+ *                                                                       *
+ * The Dimension Library is distributed in the hope that it will be      *
+ * useful, but WITHOUT ANY WARRANTY; without even the implied warranty   *
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU  *
+ * Lesser General Public License for more details.                       *
+ *                                                                       *
+ * You should have received a copy of the GNU Lesser General Public      *
+ * License along with this program.  If not, see                         *
+ * <http://www.gnu.org/licenses/>.                                       *
+ *************************************************************************/
+
+/**
+ * @file
+ * Branch profile accounting.
+ */
+
+#include "internal.h"
+#include "internal/concurrency.h"
+#include <inttypes.h>
+#include <pthread.h>
+#include <stdio.h>
+
+/// Information on one predicted branch.
+typedef struct {
+  char *location;
+  uint64_t predicted, branches;
+} dmnsn_branch;
+
+/// Count of mispredicted branches.
+static dmnsn_dictionary *dmnsn_profile = NULL;
+/// Mutex which protects \c dmnsn_profile.
+static pthread_mutex_t dmnsn_profile_mutex = PTHREAD_MUTEX_INITIALIZER;
+
+/// Thread-local count of mispredicted branches.
+static pthread_key_t dmnsn_thread_profile;
+/// Initialize the thread-specific pointer exactly once.
+static pthread_once_t dmnsn_thread_profile_once = PTHREAD_ONCE_INIT;
+
+/// Add thread-specific profile data to the global counts.
+static void
+dmnsn_profile_globalize(void *ptr)
+{
+  dmnsn_branch *branch = ptr;
+  dmnsn_branch *global = dmnsn_dictionary_at(dmnsn_profile, branch->location);
+  if (global) {
+    global->predicted += branch->predicted;
+    global->branches  += branch->branches;
+    dmnsn_free(branch->location);
+  } else {
+    dmnsn_dictionary_insert(dmnsn_profile, branch->location, branch);
+  }
+}
+
+/// Destructor function for thread-specific profile data.
+static void
+dmnsn_delete_thread_profile(void *ptr)
+{
+  dmnsn_dictionary *thread_profile = ptr;
+
+  dmnsn_lock_mutex(&dmnsn_profile_mutex);
+    dmnsn_dictionary_apply(thread_profile, dmnsn_profile_globalize);
+  dmnsn_unlock_mutex(&dmnsn_profile_mutex);
+
+  dmnsn_delete_dictionary(thread_profile);
+}
+
+/// Initialize the thread-specific pointer.
+static void
+dmnsn_initialize_thread_profile(void)
+{
+  dmnsn_key_create(&dmnsn_thread_profile, dmnsn_delete_thread_profile);
+
+  dmnsn_lock_mutex(&dmnsn_profile_mutex);
+    dmnsn_profile = dmnsn_new_dictionary(sizeof(dmnsn_branch));
+  dmnsn_unlock_mutex(&dmnsn_profile_mutex);
+}
+
+/// Get the thread-specific profile data.
+static dmnsn_dictionary *
+dmnsn_get_thread_profile(void)
+{
+  dmnsn_once(&dmnsn_thread_profile_once, dmnsn_initialize_thread_profile);
+  return pthread_getspecific(dmnsn_thread_profile);
+}
+
+/// Set the thread-specific profile data.
+static void
+dmnsn_set_thread_profile(dmnsn_dictionary *thread_profile)
+{
+  dmnsn_setspecific(dmnsn_thread_profile, thread_profile);
+}
+
+bool
+dmnsn_expect(bool result, bool expected, const char *func, const char *file,
+             unsigned int line)
+{
+  int size = snprintf(NULL, 0, "%s:%s:%u", file, func, line) + 1;
+  if (size < 1) {
+    dmnsn_error("sprintf() failed.");
+  }
+
+  char key[size];
+  if (snprintf(key, size, "%s:%s:%u", file, func, line) < 0) {
+    dmnsn_error("sprintf() failed.");
+  }
+
+  dmnsn_dictionary *thread_profile = dmnsn_get_thread_profile();
+  if (!thread_profile) {
+    thread_profile = dmnsn_new_dictionary(sizeof(dmnsn_branch));
+    dmnsn_set_thread_profile(thread_profile);
+  }
+
+  dmnsn_branch *branch = dmnsn_dictionary_at(thread_profile, key);
+  if (branch) {
+    ++branch->branches;
+    if (result == expected) {
+      ++branch->predicted;
+    }
+  } else {
+    dmnsn_branch new_branch = {
+      .location  = dmnsn_strdup(key),
+      .predicted = (result == expected) ? 1 : 0,
+      .branches  = 1
+    };
+    dmnsn_dictionary_insert(thread_profile, key, &new_branch);
+  }
+
+  return result;
+}
+
+static void
+dmnsn_print_bad_prediction(void *ptr)
+{
+  dmnsn_branch *branch = ptr;
+  double rate = ((double)branch->predicted)/branch->branches;
+  if (rate < 0.75 || branch->branches < 100000) {
+    fprintf(stderr,
+            "Bad branch prediction: %s: %" PRIu64 "/%" PRIu64 " (%g%%)\n",
+            branch->location, branch->predicted, branch->branches, 100.0*rate);
+  }
+
+  dmnsn_free(branch->location);
+}
+
+DMNSN_DESTRUCTOR static void
+dmnsn_print_bad_predictions(void)
+{
+  dmnsn_dictionary *thread_profile = dmnsn_get_thread_profile();
+  if (thread_profile) {
+    dmnsn_delete_thread_profile(thread_profile);
+    dmnsn_set_thread_profile(NULL);
+  }
+
+  dmnsn_lock_mutex(&dmnsn_profile_mutex);
+    dmnsn_dictionary_apply(dmnsn_profile, dmnsn_print_bad_prediction);
+    dmnsn_delete_dictionary(dmnsn_profile);
+    dmnsn_profile = NULL;
+  dmnsn_unlock_mutex(&dmnsn_profile_mutex);
+}