posix: Avoid static initializers in static/global mutexes

This patch removes static initializers related to static and
global mutexes from the final library's machine code when
building on a pthread-capable system.

We use PTHREAD_MUTEX_INITIALIZER to perform POD-style
initialization. You need a line like the following to declare
a global mutex with it:

    SkBaseMutex gMutex = { PTHREAD_MUTEX_INITIALIZER };

We introduce the SK_DECLARE_STATIC_MUTEX and SK_DECLARE_GLOBAL_MUTEX
macros to be able to declare static/global mutexes in the source tree
uniformly.

SkMutex is now defined as a sub-class of SkBaseMutex, with standard
construction/destruction semantics. This is useful if the mutex
object is a member of another C++ class, or allocated dynamically.

We also modify a few places to refer to SkBaseMutex instead of a
SkMutex, where it makes sense. Generally speaking, client code
should hold and use pointers to SkBaseMutex whenever they can
now.

We defined a new built-time macro named SK_USE_POSIX_THREADS
to indicate that we're using a pthread-based SkThread.h
interface. The macro will also be used in future patches
to implement other helper thread synchronization classes.

Finally, we inline the acquire() and release() functions in the
case of Posix to improve performance a bit.

Running: 'bench -repeat 10 -match mutex' on an Android device or
a 2.4GHz Xeon Linux desktop shows the following improvements:

                      Before     After

        Galaxy Nexus    1.64      1.45
        Nexus S         1.47      1.16
        Xoom            1.86      1.66
        Xeon            0.36      0.31

This removes 5 static mutex initializers from the library
Review URL: https://codereview.appspot.com/5501066

git-svn-id: http://skia.googlecode.com/svn/trunk@3091 2bbb7eff-a529-9590-31e7-b0007b416f81

9 files changed, 34 insertions, 9 deletions

diff --git a/src/ports/SkFontHost_FreeType.cpp b/src/ports/SkFontHost_FreeType.cpp
index a58cd3702c..caca577ac7 100644
--- a/src/ports/SkFontHost_FreeType.cpp
+++ b/src/ports/SkFontHost_FreeType.cpp
@@ -88,7 +88,7 @@ static bool isLCD(const SkScalerContext::Rec& rec) {
 
 struct SkFaceRec;
 
-static SkMutex      gFTMutex;
+SK_DECLARE_STATIC_MUTEX(gFTMutex);
 static int          gFTCount;
 static FT_Library   gFTLibrary;
 static SkFaceRec*   gFaceRecHead;
diff --git a/src/ports/SkFontHost_android.cpp b/src/ports/SkFontHost_android.cpp
index 37c922c6c2..a3bd79c721 100644
--- a/src/ports/SkFontHost_android.cpp
+++ b/src/ports/SkFontHost_android.cpp
@@ -67,7 +67,7 @@ struct NameFamilyPair {
 static int32_t gUniqueFontID;
 
 // this is the mutex that protects these globals
-static SkMutex gFamilyMutex;
+SK_DECLARE_STATIC_MUTEX(gFamilyMutex);
 static FamilyRec* gFamilyHead;
 static SkTDArray<NameFamilyPair> gNameList;
 
diff --git a/src/ports/SkFontHost_fontconfig.cpp b/src/ports/SkFontHost_fontconfig.cpp
index acc5ae046e..454ded3d20 100644
--- a/src/ports/SkFontHost_fontconfig.cpp
+++ b/src/ports/SkFontHost_fontconfig.cpp
@@ -38,7 +38,7 @@ SkTypeface::Style find_name_and_style(SkStream* stream, SkString* name);
 // Although truetype fonts can support multiple faces in a single file, at the
 // moment Skia doesn't.
 // -----------------------------------------------------------------------------
-static SkMutex global_fc_map_lock;
+SK_DECLARE_STATIC_MUTEX(global_fc_map_lock);
 static std::map<std::string, unsigned> global_fc_map;
 static std::map<unsigned, std::string> global_fc_map_inverted;
 static std::map<uint32_t, SkTypeface *> global_fc_typefaces;
diff --git a/src/ports/SkFontHost_linux.cpp b/src/ports/SkFontHost_linux.cpp
index c87b03634e..fa1d2eca66 100644
--- a/src/ports/SkFontHost_linux.cpp
+++ b/src/ports/SkFontHost_linux.cpp
@@ -60,7 +60,7 @@ struct NameFamilyPair {
 static int32_t gUniqueFontID;
 
 // this is the mutex that protects these globals
-static SkMutex gFamilyMutex;
+SK_DECLARE_STATIC_MUTEX(gFamilyMutex);
 static FamilyRec* gFamilyHead;
 static SkTDArray<NameFamilyPair> gNameList;
 
diff --git a/src/ports/SkFontHost_mac_atsui.cpp b/src/ports/SkFontHost_mac_atsui.cpp
index b90757cf5c..ae3203668c 100644
--- a/src/ports/SkFontHost_mac_atsui.cpp
+++ b/src/ports/SkFontHost_mac_atsui.cpp
@@ -16,7 +16,7 @@
 #include "SkPoint.h"
 
 const char* gDefaultfont = "Arial"; // hard code for now
-static SkMutex      gFTMutex;
+SK_DECLARE_STATIC_MUTEX(gFTMutex);
 
 static inline SkPoint F32PtToSkPoint(const Float32Point p) {
     SkPoint sp = { SkFloatToScalar(p.x), SkFloatToScalar(p.y) };
diff --git a/src/ports/SkFontHost_mac_coretext.cpp b/src/ports/SkFontHost_mac_coretext.cpp
index 3ba11a8c0a..9c69ed7043 100644
--- a/src/ports/SkFontHost_mac_coretext.cpp
+++ b/src/ports/SkFontHost_mac_coretext.cpp
@@ -450,7 +450,7 @@ static CTFontRef GetFontRefFromFontID(SkFontID fontID) {
 }
 
 static SkTypeface* GetDefaultFace() {
-    static SkMutex gMutex;
+    SK_DECLARE_STATIC_MUTEX(gMutex);
     SkAutoMutexAcquire ma(gMutex);
 
     static SkTypeface* gDefaultFace;
diff --git a/src/ports/SkFontHost_simple.cpp b/src/ports/SkFontHost_simple.cpp
index 0624d359a2..7a06b10d65 100644
--- a/src/ports/SkFontHost_simple.cpp
+++ b/src/ports/SkFontHost_simple.cpp
@@ -59,7 +59,7 @@ struct NameFamilyPair {
 static int32_t gUniqueFontID;
 
 // this is the mutex that protects these globals
-static SkMutex gFamilyMutex;
+SK_DECLARE_STATIC_MUTEX(gFamilyMutex);
 static FamilyRec* gFamilyHead;
 static SkTDArray<NameFamilyPair> gNameList;
 
diff --git a/src/ports/SkFontHost_win.cpp b/src/ports/SkFontHost_win.cpp
index 156f51cff2..e78bfbb222 100755
--- a/src/ports/SkFontHost_win.cpp
+++ b/src/ports/SkFontHost_win.cpp
@@ -448,7 +448,7 @@ static FIXED float2FIXED(float x) {
     return SkFixedToFIXED(SkFloatToFixed(x));
 }
 
-static SkMutex gFTMutex;
+SK_DECLARE_STATIC_MUTEX(gFTMutex);
 
 #define HIRES_TEXTSIZE  2048
 #define HIRES_SHIFT     11
diff --git a/src/ports/SkThread_pthread.cpp b/src/ports/SkThread_pthread.cpp
index 638e522e3b..4750d4f2c4 100644
--- a/src/ports/SkThread_pthread.cpp
+++ b/src/ports/SkThread_pthread.cpp
@@ -55,7 +55,7 @@ int32_t sk_atomic_inc(int32_t* addr)
 int32_t sk_atomic_dec(int32_t* addr)
 {
     SkAutoMutexAcquire ac(gAtomicMutex);
-    
+
     int32_t value = *addr;
     *addr = value - 1;
     return value;
@@ -83,6 +83,30 @@ static void print_pthread_error(int status) {
     }
 }
 
+#ifdef SK_USE_POSIX_THREADS
+
+SkMutex::SkMutex() {
+    int status;
+
+    status = pthread_mutex_init(&fMutex, NULL);
+    if (status != 0) {
+        print_pthread_error(status);
+        SkASSERT(0 == status);
+    }
+}
+
+SkMutex::~SkMutex() {
+    int status = pthread_mutex_destroy(&fMutex);
+
+    // only report errors on non-global mutexes
+    if (status != 0) {
+        print_pthread_error(status);
+        SkASSERT(0 == status);
+    }
+}
+
+#else // !SK_USE_POSIX_THREADS
+
 SkMutex::SkMutex() {
     if (sizeof(pthread_mutex_t) > sizeof(fStorage)) {
         SkDEBUGF(("pthread mutex size = %d\n", sizeof(pthread_mutex_t)));
@@ -124,3 +148,4 @@ void SkMutex::release() {
     SkASSERT(0 == status);
 }
 
+#endif // !SK_USE_POSIX_THREADS