[libpng15] Fixed PNG_ALIGN(ED)_MEMORY and add ability to turn off ARM_NEON

runtime checks

ANNOUNCE

@@ -1,5 +1,5 @@
 
-Libpng 1.5.15beta06 - February 18, 2013
+Libpng 1.5.15beta06 - February 19, 2013
 
 This is not intended to be a public release.  It will be replaced
 within a few weeks by a public version or by another test version.
@@ -55,9 +55,11 @@ Version 1.5.15beta05 [February 17, 2013]
     library calls.
   Fixed a race condition in the creation of the build 'scripts' directory
     while building with a parallel make.
-  Use parentheses more consistently in "#if define(MACRO)" tests.
+  Use parentheses more consistently in "#if defined(MACRO)" tests.
 
-Version 1.5.15beta06 [February 18, 2013]
+Version 1.5.15beta06 [February 19, 2013]
+  Fixed PNG_ALIGN(ED)_MEMORY and add ability to turn off ARM_NEON
+    runtime checks
 
 Send comments/corrections/commendations to png-mng-implement at lists.sf.net
 (subscription required; visit

CHANGES

@@ -4013,9 +4013,11 @@ Version 1.5.15beta05 [February 17, 2013]
     library calls.
   Fixed a race condition in the creation of the build 'scripts' directory
     while building with a parallel make.
-  Use parentheses more consistently in "#if define(MACRO)" tests.
+  Use parentheses more consistently in "#if defined(MACRO)" tests.
 
-Version 1.5.15beta06 [February 18, 2013]
+Version 1.5.15beta06 [February 19, 2013]
+  Fixed PNG_ALIGN(ED)_MEMORY and add ability to turn off ARM_NEON
+    runtime checks
 
   ===========================================================================
                        NOTICE November 17, 2012:

arm/arm_init.c

@@ -16,12 +16,17 @@
 
 #include "../pngpriv.h"
 
+#if defined(PNG_FILTER_OPTIMIZATIONS) && defined(__arm__) && \
+   defined(__ARM_NEON__)
 /* __arm__ is defined by GCC, MSVC defines _M_ARM to the ARM version number,
  * Andoid intends to define __ANDROID__, however there are bugs in their
  * toolchain; use -D__ANDROID__ to work round this.
+ *
+ * __ARM_NEON__ is used to ensure that the compiler has the appropriate ARM
+ * NEON support
  */
-#if defined __linux__ && defined __arm__
-#define CHECK_NEON
+
+#ifdef PNG_ARM_NEON_CHECK_SUPPORTED /* Do run-time checks */
 #include <signal.h> /* for sig_atomic_t */
 
 #ifdef __ANDROID__
@@ -43,7 +48,7 @@ png_have_neon(png_structp png_ptr)
    return andoid_getCpuFamily() == ANDROID_CPU_FAMILY_ARM &&
       (android_getCpuFeatures() & ANDROID_CPU_ARM_FEATURE_NEON) != 0;
 }
-#else
+#elif defined(__linux__)
 /* The generic __linux__ implementation requires reading /proc/self/auxv and
  * looking at each element for one that records NEON capabilities.
  */
@@ -143,14 +148,20 @@ png_have_neon(png_structp png_ptr)
    close(fd);
    return 0;
 }
-#endif /* !__ANDROID__ */
-#endif /* __linux__ && __arm__ */
+#else
+   /* We don't know how to do a run-time check on this system */
+#  error "no support for run-time ARM NEON checks"
+#endif /* OS checks */
+#endif /* PNG_ARM_NEON_CHECK_SUPPORTED */
+
+#ifndef PNG_ALIGNED_MEMORY_SUPPORTED
+#  error "ALIGNED_MEMORY is required; set: -DPNG_ALIGNED_MEMORY_SUPPORTED"
+#endif
 
 void
 png_init_filter_functions_neon(png_structp pp, unsigned int bpp)
 {
-#ifdef __arm__
-#ifdef CHECK_NEON
+#ifdef PNG_ARM_NEON_CHECK_SUPPORTED
    static volatile sig_atomic_t no_neon = -1; /* not checked */
 
    if (no_neon < 0)
@@ -158,7 +169,7 @@ png_init_filter_functions_neon(png_structp pp, unsigned int bpp)
 
    if (no_neon)
       return;
-#endif
+#endif /* PNG_ARM_NEON_CHECK_SUPPORTED */
 
    /* IMPORTANT: any new external functions used here must be declared using
     * PNG_INTERNAL_FUNCTION in ../pngpriv.h.  This is required so that the
@@ -188,8 +199,5 @@ png_init_filter_functions_neon(png_structp pp, unsigned int bpp)
       pp->read_filter[PNG_FILTER_VALUE_PAETH-1] =
           png_read_filter_row_paeth4_neon;
    }
-#else
-   PNG_UNUSED(pp)
-   PNG_UNUSED(bpp)
-#endif
 }
+#endif /* FILTER_OPTIMIZATIONS && __arm__ && __ARM_NEON__ */

arm/filter_neon.S

@@ -10,11 +10,14 @@
  * and license in png.h
  */
 
-/* This is required to get the symbol renames, which are #defines */
+/* This is required to get the symbol renames, which are #defines, and also
+ * includes the value of PNG_FILTER_OPTIMIZATIONS.
+ */
 #define PNG_VERSION_INFO_ONLY
 #include "../pngpriv.h"
 
-#ifdef __arm__
+#if defined(PNG_FILTER_OPTIMIZATIONS) && defined(__arm__) && \
+   defined(__ARM_NEON__)
 #if defined(__linux__) && defined(__ELF__)
 .section .note.GNU-stack,"",%progbits /* mark stack as non-executable */
 #endif
@@ -229,4 +232,4 @@ func    png_read_filter_row_paeth3_neon, export=1
 
         pop             {r4,pc}
 endfunc
-#endif
+#endif /* FILTER_OPTIMIZATIONS && __arm__ && __ARM_NEON__ */

configure.ac

@@ -172,15 +172,22 @@ AC_SUBST([binconfigs])
 AC_SUBST([AM_CCASFLAGS], [-Wa,--noexecstack])
 
 AC_ARG_ENABLE([arm-neon],
-	AC_HELP_STRING([--enable-arm-neon], [Enable ARM NEON optimizations]),
-	[if test "${enableval}" = yes; then
-		AC_DEFINE([PNG_FILTER_OPTIMIZATIONS],
-                          [png_init_filter_functions_neon],
-                          [ARM NEON filter initialization function])
-		AC_DEFINE([PNG_ALIGNED_MEMORY_SUPPORTED], [1],
-                          [Align row buffers])
-	fi])
-AM_CONDITIONAL([PNG_ARM_NEON], [test "${enable_arm_neon:-no}" = yes])
+   AS_HELP_STRING([[[--enable-arm-neon]]],
+      [Enable ARM NEON optimizations: use 'always' to turn off run-time checks]),
+   [if test "${enableval}" = "yes" -o "${enableval}" = "always"; then
+       AC_DEFINE([PNG_FILTER_OPTIMIZATIONS],
+                 [png_init_filter_functions_neon],
+                 [ARM NEON filter initialization function])
+      AC_DEFINE([PNG_ALIGNED_MEMORY_SUPPORTED], [1],
+                [Align row buffers])
+      if test "${enableval}" = "always"; then
+         AC_DEFINE([PNG_NO_ARM_NEON_CHECK], [],
+                   [Turn off run-time checking for ARM NEON support])
+      fi
+    fi])
+AM_CONDITIONAL([PNG_ARM_NEON], [test "${enable_arm_neon:-no}" != "no"])
+ 
+ AC_MSG_NOTICE([[Extra options for compiler: $PNG_COPTS]])
 
 # Config files, substituting as above
 AC_CONFIG_FILES([Makefile libpng.pc:libpng.pc.in])

scripts/pnglibconf.dfa

@@ -127,6 +127,12 @@ logunsupported = 1
 # - PNG_USER_VERSIONINFO_COMPANYNAME
 # - PNG_USER_VERSIONINFO_LEGALTRADEMARKS
 
+# It is necessary to include configures definitions here so that AC_DEFINE
+# in configure.ac works in a comprehensible way
+@#if defined(HAVE_CONFIG_H) && !defined(PNG_NO_CONFIG_H)
+@#  include "config.h"
+@#endif
+
 @#ifdef PNG_USER_CONFIG
 @#  include "pngusr.h"
 @#endif
@@ -179,6 +185,18 @@ option READ_INT_FUNCTIONS requires READ
 option WRITE_INT_FUNCTIONS disabled
 option WRITE enables WRITE_INT_FUNCTIONS
 
+# This setting allows a hardware or configuration specific filter optimization
+# function to be specified, the argument is the name of the filter initializaion
+# function to use.
+
+setting FILTER_OPTIMIZATIONS
+
+# This option turns on runtime checks for ARM NEON support, it is irrelevant
+# on other platforms and it is irrelevant unless NEON code is turned on.  Checks
+# are on by default
+
+option ARM_NEON_CHECK
+
 # Generic options - affect both read and write.
 
 option WARNINGS
@@ -446,7 +464,7 @@ option CHECK_cHRM requires cHRM
 # but can help (in theory) on some architectures.  Only affects
 # internal structures.  Added at libpng 1.4.0
 
-option ALIGN_MEMORY
+option ALIGNED_MEMORY
 
 # Buggy compilers (e.g., gcc 2.7.2.2) need PNG_NO_POINTER_INDEXING
 # See png[wr]util.c, normally this should always be *on*

scripts/pnglibconf.h.prebuilt

@@ -3,7 +3,7 @@
 
 /* pnglibconf.h - library build configuration */
 
-/* Libpng 1.5.15beta06 - February 18, 2013 */
+/* Libpng 1.5.15beta06 - February 19, 2013 */
 
 /* Copyright (c) 1998-2012 Glenn Randers-Pehrson */
 
@@ -36,7 +36,8 @@
 /* end of settings */
 /* options */
 #define PNG_16BIT_SUPPORTED 1
-#define PNG_ALIGN_MEMORY_SUPPORTED 1
+#define PNG_ALIGNED_MEMORY_SUPPORTED
+#define PNG_ARM_NEON_CHECK_SUPPORTED
 #define PNG_BENIGN_ERRORS_SUPPORTED 1
 #define PNG_BUILD_GRAYSCALE_PALETTE_SUPPORTED 1
 #define PNG_CHECK_FOR_INVALID_INDEX_SUPPORTED 1