Add dmnsn_[un]likely() macros and a profiling framework.

8 files changed, 218 insertions, 15 deletions

diff --git a/libdimension/Makefile.am b/libdimension/Makefile.am
index 1d5077c..6a8d4bb 100644
--- a/libdimension/Makefile.am
+++ b/libdimension/Makefile.am
@@ -65,6 +65,7 @@ libdimension_la_SOURCES = $(nobase_include_HEADERS)                            \
                           checker.c                                            \
                           color.c                                              \
                           color_map.c                                          \
+                          compiler.h                                           \
                           cone.c                                               \
                           cube.c                                               \
                           csg.c                                                \
@@ -91,6 +92,7 @@ libdimension_la_SOURCES = $(nobase_include_HEADERS)                            \
                           plane.c                                              \
                           platform.c                                           \
                           platform.h                                           \
+                          profile.h                                            \
                           point_light.c                                        \
                           polynomial.c                                         \
                           progress.c                                           \
@@ -126,6 +128,10 @@ else
 libdimension_la_SOURCES += gl-stubs.c
 endif
 
+if PROFILE
+libdimension_la_SOURCES += profile.c
+endif
+
 clean-local: clean-docs
 
 doc:
diff --git a/libdimension/compiler.h b/libdimension/compiler.h
new file mode 100644
index 0000000..b1cf60c
--- /dev/null
+++ b/libdimension/compiler.h
@@ -0,0 +1,44 @@
+/*************************************************************************
+ * Copyright (C) 2010 Tavian Barnes <tavianator@gmail.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
+ * Compiler abstractions.
+ */
+
+#ifndef DIMENSION_IMPL_COMPILER_H
+#define DIMENSION_IMPL_COMPILER_H
+
+#include <stdbool.h>
+
+#if DMNSN_PROFILE
+#define dmnsn_likely(test)                                      \
+  dmnsn_expect((test), true, DMNSN_FUNC, __FILE__, __LINE__)
+#define dmnsn_unlikely(test)                                    \
+  dmnsn_expect((test), false, DMNSN_FUNC, __FILE__, __LINE__)
+#elif defined(__GNUC__)
+#define dmnsn_likely(test)   __builtin_expect(!!(test), true)
+#define dmnsn_unlikely(test) __builtin_expect(!!(test), false)
+#else
+#define dmnsn_likely(test)   (test)
+#define dmnsn_unlikely(test) (test)
+#endif
+
+#endif /* DIMENSION_IMPL_COMPILER_H */
diff --git a/libdimension/dimension-impl.h b/libdimension/dimension-impl.h
index 2746b1c..4712a1f 100644
--- a/libdimension/dimension-impl.h
+++ b/libdimension/dimension-impl.h
@@ -29,8 +29,10 @@
 
 #define _GNU_SOURCE
 #include "dimension.h"
-#include "progress-impl.h"
+#include "compiler.h"
+#include "profile.h"
 #include "platform.h"
+#include "progress-impl.h"
 #include "threads.h"
 #include "prtree.h"
 
diff --git a/libdimension/dimension.h b/libdimension/dimension.h
index 9f7fd67..73cab50 100644
--- a/libdimension/dimension.h
+++ b/libdimension/dimension.h
@@ -44,6 +44,21 @@
 extern "C" {
 #endif
 
+/* Common macros */
+
+/**
+ * @internal
+ * @def DMNSN_FUNC
+ * @brief Expands to the name of the current function
+ */
+#ifdef __GNUC__
+  #define DMNSN_FUNC __PRETTY_FUNCTION__
+#elif __STDC_VERSION__ >= 199901L
+  #define DMNSN_FUNC __func__
+#else
+  #define DMNSN_FUNC "<unknown function>"
+#endif
+
 /* Common types */
 
 /**
diff --git a/libdimension/dimension/error.h b/libdimension/dimension/error.h
index fd78115..d785f96 100644
--- a/libdimension/dimension/error.h
+++ b/libdimension/dimension/error.h
@@ -37,19 +37,6 @@ typedef enum dmnsn_severity {
 } dmnsn_severity;
 
 /**
- * @internal
- * @def DMNSN_FUNC
- * @brief Expands to the name of the current function
- */
-#ifdef __GNUC__
-  #define DMNSN_FUNC __PRETTY_FUNCTION__
-#elif __STDC_VERSION__ >= 199901L
-  #define DMNSN_FUNC __func__
-#else
-  #define DMNSN_FUNC "<unknown function>"
-#endif
-
-/**
  * Report an error.
  * @param[in] severity  A @ref dmnsn_severity representing the severity of the
  *                      error.  DMNSN_SEVERITY_HIGH will always terminate the
diff --git a/libdimension/png.c b/libdimension/png.c
index 63cb71e..5fe51ed 100644
--- a/libdimension/png.c
+++ b/libdimension/png.c
@@ -24,7 +24,6 @@
  */
 
 #include "dimension-impl.h"
-#include <pthread.h>
 #include <png.h>
 #include <errno.h>
 #include <setjmp.h>
diff --git a/libdimension/profile.c b/libdimension/profile.c
new file mode 100644
index 0000000..c88e3ef
--- /dev/null
+++ b/libdimension/profile.c
@@ -0,0 +1,106 @@
+/*************************************************************************
+ * Copyright (C) 2010 Tavian Barnes <tavianator@gmail.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 "dimension-impl.h"
+#include <pthread.h>
+#include <stdio.h>
+#include <inttypes.h>
+
+/** Info for one predicted branch. */
+typedef struct {
+  char *location;
+  uint64_t predicted, branches;
+} dmnsn_profile_info;
+
+/** Count of mispredicted branches. */
+static dmnsn_dictionary *dmnsn_profile_data = NULL;
+/** Mutex which protects \c dmnsn_profile_data. */
+static pthread_mutex_t dmnsn_profile_mutex = PTHREAD_MUTEX_INITIALIZER;
+
+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(DMNSN_SEVERITY_MEDIUM, "sprintf() failed.");
+  } else {
+    char key[size];
+    if (snprintf(key, size, "%s:%s:%u", file, func, line) > 0) {
+      if (pthread_mutex_lock(&dmnsn_profile_mutex) != 0) {
+        dmnsn_error(DMNSN_SEVERITY_MEDIUM, "Couldn't lock mutex.");
+      }
+
+      if (!dmnsn_profile_data) {
+        dmnsn_profile_data = dmnsn_new_dictionary(sizeof(dmnsn_profile_info));
+      }
+      dmnsn_profile_info *info = dmnsn_dictionary_at(dmnsn_profile_data, key);
+      if (info) {
+        ++info->branches;
+        if (result == expected) {
+          ++info->predicted;
+        }
+      } else {
+        dmnsn_profile_info info = {
+          .location  = dmnsn_strdup(key),
+          .predicted = (result == expected) ? 1 : 0,
+          .branches  = 1
+        };
+        dmnsn_dictionary_insert(dmnsn_profile_data, key, &info);
+      }
+
+      if (pthread_mutex_unlock(&dmnsn_profile_mutex) != 0) {
+        dmnsn_error(DMNSN_SEVERITY_MEDIUM, "Couldn't lock mutex.");
+      }
+    } else {
+      dmnsn_error(DMNSN_SEVERITY_MEDIUM, "sprintf() failed.");
+    }
+  }
+
+  return result;
+}
+
+static void
+dmnsn_print_bad_prediction(void *ptr)
+{
+  dmnsn_profile_info *info = ptr;
+  double rate = ((double)info->predicted)/info->branches;
+  if (rate < 0.75 || info->branches < 100000) {
+    fprintf(stderr,
+            "Bad branch prediction: %s: %" PRIu64 "/%" PRIu64 "\n",
+            info->location, info->predicted, info->branches);
+  }
+
+  dmnsn_free(info->location);
+}
+
+static void __attribute__((destructor))
+dmnsn_print_bad_predictions(void)
+{
+  if (dmnsn_profile_data) {
+    dmnsn_dictionary_apply(dmnsn_profile_data, &dmnsn_print_bad_prediction);
+    dmnsn_delete_dictionary(dmnsn_profile_data);
+  }
+}
diff --git a/libdimension/profile.h b/libdimension/profile.h
new file mode 100644
index 0000000..e891771
--- /dev/null
+++ b/libdimension/profile.h
@@ -0,0 +1,44 @@
+/*************************************************************************
+ * Copyright (C) 2010 Tavian Barnes <tavianator@gmail.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
+ * Built-in branch profiler.
+ */
+
+#ifndef DIMENSION_IMPL_PROFILE_H
+#define DIMENSION_IMPL_PROFILE_H
+
+#include <stdbool.h>
+
+/**
+ * Record an test and its expected result.  Called by dmnsn_[un]likely();
+ * don't call directly.
+ * @param[in] value     The result of the test.
+ * @param[in] expected  The expected result of the test.
+ * @param[in] func      The name of the function the test occurs in.
+ * @param[in] file      The name of the file the test occurs in.
+ * @param[in] line      The line number on which the test occurs.
+ * @return \p value.
+ */
+bool dmnsn_expect(bool result, bool expected,
+                  const char *func, const char *file, unsigned int line);
+
+#endif /* DIMENSION_IMPL_PROFILE_H */