Replacing FloatMath native implementation with calls to Math

On modern versions of Android running in AOT mode
FloatMath is slower than Math. Calls to Math.sqrt(),
etc. are replaced by intrinsics which can be as small
as a single CPU opcode.

When running in interpreted mode the new
implementation is unfortunately slower, but I'm
judging this acceptable and likely to be improved
over time. This change saves a small amount of native
code.

Example timings:

Mako AOSP AOT:

Method: Original / New / Direct call to Math
ceil: 596ns / 146.ns / 111ns
sqrt: 694ns / 56ns / 25ns

Mako AOSP interpreted:

Method: Original / New / Direct call to Math
ceil: 1900ns / 2307ns / 1485ns
sqrt: 1998ns / 2603ns / 1788ns

Other calls Mako AOT:

Method: Original / New
cos: 635ns / 270ns
exp: 566ns / 324ns
floor: 604ns / 150ns
hypot: 631ns / 232ns
pow: 936ns / 643ns
sin: 641ns / 299ns

The advice to use Math directly, in preference to
FloatMath, is still good. FloatMath will be deprecated
separately.

Bug: https://code.google.com/p/android/issues/detail?id=36199
Change-Id: If07fcbd78543d13bc6d75f9743f999860e8d58d7

3 files changed, 0 insertions, 65 deletions

diff --git a/core/jni/Android.mk b/core/jni/Android.mk
index 5d10f3c..9b3b091 100644
--- a/core/jni/Android.mk
+++ b/core/jni/Android.mk
@@ -80,7 +80,6 @@ LOCAL_SRC_FILES:= \
 	android_util_Binder.cpp \
 	android_util_EventLog.cpp \
 	android_util_Log.cpp \
-	android_util_FloatMath.cpp \
 	android_util_Process.cpp \
 	android_util_StringBlock.cpp \
 	android_util_XmlBlock.cpp \
diff --git a/core/jni/AndroidRuntime.cpp b/core/jni/AndroidRuntime.cpp
index 0d2cdb9..796a0c3 100644
--- a/core/jni/AndroidRuntime.cpp
+++ b/core/jni/AndroidRuntime.cpp
@@ -90,8 +90,6 @@ extern int register_android_media_AudioTrack(JNIEnv *env);
 extern int register_android_media_JetPlayer(JNIEnv *env);
 extern int register_android_media_ToneGenerator(JNIEnv *env);
 
-extern int register_android_util_FloatMath(JNIEnv* env);
-
 namespace android {
 
 /*
@@ -1229,7 +1227,6 @@ static const RegJNIRec gRegJNI[] = {
     REG_JNI(register_android_os_SystemClock),
     REG_JNI(register_android_util_EventLog),
     REG_JNI(register_android_util_Log),
-    REG_JNI(register_android_util_FloatMath),
     REG_JNI(register_android_content_AssetManager),
     REG_JNI(register_android_content_StringBlock),
     REG_JNI(register_android_content_XmlBlock),
diff --git a/core/jni/android_util_FloatMath.cpp b/core/jni/android_util_FloatMath.cpp
deleted file mode 100644
index 73b7a6f..0000000
--- a/core/jni/android_util_FloatMath.cpp
+++ /dev/null
@@ -1,61 +0,0 @@
-#include "jni.h"
-#include <android_runtime/AndroidRuntime.h>
-#include <math.h>
-#include <float.h>
-#include "SkTypes.h"
-
-class MathUtilsGlue {
-public:
-    static float FloorF(JNIEnv* env, jobject clazz, float x) {
-        return floorf(x);
-    }
-    
-    static float CeilF(JNIEnv* env, jobject clazz, float x) {
-        return ceilf(x);
-    }
-    
-    static float SinF(JNIEnv* env, jobject clazz, float x) {
-        return sinf(x);
-    }
-    
-    static float CosF(JNIEnv* env, jobject clazz, float x) {
-        return cosf(x);
-    }
-    
-    static float SqrtF(JNIEnv* env, jobject clazz, float x) {
-        return sqrtf(x);
-    }
-
-    static float ExpF(JNIEnv* env, jobject clazz, float x) {
-        return expf(x);
-    }
-
-    static float PowF(JNIEnv* env, jobject clazz, float x, float y) {
-        return powf(x, y);
-    }
-
-    static float HypotF(JNIEnv* env, jobject clazz, float x, float y) {
-        return hypotf(x, y);
-    }
-};
-
-static JNINativeMethod gMathUtilsMethods[] = {
-    {"floor", "(F)F", (void*) MathUtilsGlue::FloorF},
-    {"ceil", "(F)F", (void*) MathUtilsGlue::CeilF},
-    {"sin", "(F)F", (void*) MathUtilsGlue::SinF},
-    {"cos", "(F)F", (void*) MathUtilsGlue::CosF},
-    {"sqrt", "(F)F", (void*) MathUtilsGlue::SqrtF},
-    {"exp", "(F)F", (void*) MathUtilsGlue::ExpF},
-    {"pow", "(FF)F", (void*) MathUtilsGlue::PowF},
-    {"hypot", "(FF)F", (void*) MathUtilsGlue::HypotF},
-};
-
-int register_android_util_FloatMath(JNIEnv* env)
-{
-    int result = android::AndroidRuntime::registerNativeMethods(env,
-                                            "android/util/FloatMath",
-                                            gMathUtilsMethods,
-                                            SK_ARRAY_COUNT(gMathUtilsMethods));
-    return result;
-}
-