Enable both static and dynamically linked libpng

All platforms except android are configured to use the statically linked copy
of libpng. Android uses the system provided dynamic copy for SkImageDecoder
and the static copy for SkCodec. The exception being android framework builds
that currently use the dynamic copy everywhere.

This CL also enables NEON optimizations for libpng.

Review URL: https://codereview.chromium.org/1058823002

3 files changed, 107 insertions, 78 deletions

diff --git a/gyp/codec.gyp b/gyp/codec.gyp
index eb49f6cd5c..1373773940 100644
--- a/gyp/codec.gyp
+++ b/gyp/codec.gyp
@@ -18,7 +18,6 @@
       'dependencies': [
         'core.gyp:*',
         'giflib.gyp:giflib',
-        'libpng.gyp:libpng',
       ],
       'cflags':[
         # FIXME: This gets around a longjmp warning. See
@@ -47,6 +46,21 @@
           '../include/codec',
         ],
       },
+      'conditions': [
+        [ 'skia_android_framework == 1',
+          {
+            # TODO(djsollen): this is a temporary dependency until we can update
+            # the android framework to a more recent version of libpng.
+            'dependencies': [
+              'libpng.gyp:libpng',
+            ],
+          }, {  # !skia_android_framework
+            'dependencies': [
+              'libpng.gyp:libpng_static',
+            ],
+          }
+        ]
+      ]
     },
   ],
 }
diff --git a/gyp/common_variables.gypi b/gyp/common_variables.gypi
index b9f0bd7a9a..3cd3fc4f5b 100644
--- a/gyp/common_variables.gypi
+++ b/gyp/common_variables.gypi
@@ -162,15 +162,6 @@
       }, {
         'skia_release_optimization_level%': '<(skia_default_gcc_optimization_level)',
       }],
-      [ 'skia_os == "android"', {
-          # skia_libpng_static - instead of linking libpng with '-lpng' and
-          #     including the headers from '/usr/include/png.h', compile and
-          #     statically link the version of libpng in
-          #     third_party/externals/libpng.
-          'skia_libpng_static%': '0',
-      }, {
-          'skia_libpng_static%': '1',
-      }],
       [ 'skia_sanitizer', {
         'skia_clang_build': 1,
         'skia_keep_frame_pointer': 1,
diff --git a/gyp/libpng.gyp b/gyp/libpng.gyp
index 73bdd2aa3c..d918f2d403 100644
--- a/gyp/libpng.gyp
+++ b/gyp/libpng.gyp
@@ -10,85 +10,109 @@
   'targets': [
     {
       'target_name': 'libpng',
+      'type': 'none',
       'conditions': [
-        [ 'skia_libpng_static',
+        [ 'skia_os == "android"',
           {
-            'type': 'static_library',
-            'include_dirs': [
-              '../third_party/externals/libpng',
-              # Needed for generated pnglibconf.h
-              '../third_party/libpng',
-            ],
             'dependencies': [
-              'zlib.gyp:zlib',
+              'android_deps.gyp:png',
             ],
             'export_dependent_settings': [
-              'zlib.gyp:zlib',
-            ],
-            'direct_dependent_settings': {
-              'include_dirs': [
-                '../third_party/externals/libpng',
-                # Needed for generated pnglibconf.h
-                '../third_party/libpng',
-              ],
-            },
-            'cflags': [
-              '-w',
-              '-fvisibility=hidden',
+              'android_deps.gyp:png',
             ],
-            'defines': [
-                # TODO: it'd be nice to enable PNG's NEON when possible.
-                'PNG_ARM_NEON_OPT=0',
+          }, {  # skia_os != "android"
+            'dependencies': [
+              'libpng.gyp:libpng_static',
             ],
-            'sources': [
-              '../third_party/externals/libpng/png.c',
-              '../third_party/externals/libpng/pngerror.c',
-              '../third_party/externals/libpng/pngget.c',
-              '../third_party/externals/libpng/pngmem.c',
-              '../third_party/externals/libpng/pngpread.c',
-              '../third_party/externals/libpng/pngread.c',
-              '../third_party/externals/libpng/pngrio.c',
-              '../third_party/externals/libpng/pngrtran.c',
-              '../third_party/externals/libpng/pngrutil.c',
-              '../third_party/externals/libpng/pngset.c',
-              '../third_party/externals/libpng/pngtrans.c',
-              '../third_party/externals/libpng/pngwio.c',
-              '../third_party/externals/libpng/pngwrite.c',
-              '../third_party/externals/libpng/pngwtran.c',
-              '../third_party/externals/libpng/pngwutil.c',
+            'export_dependent_settings': [
+              'libpng.gyp:libpng_static',
             ],
-          }, {  # not skia_libpng_static
-            'type': 'none',
-            'conditions': [
-              [ 'skia_os == "android"',
-                {
-                  # TODO(halcanary): merge all png targets into this file.
-                  'dependencies': [
-                    'android_deps.gyp:png',
-                  ],
-                  'export_dependent_settings': [
-                    'android_deps.gyp:png',
-                  ],
-                }, {  # skia_os != "android"
-                  'dependencies': [
-                    'zlib.gyp:zlib',
-                    ],
-                  'export_dependent_settings': [
-                    'zlib.gyp:zlib',
-                    ],
-                  'direct_dependent_settings': {
-                    'link_settings': {
-                      'libraries': [
-                        '-lpng',
-                      ],
-                    },
-                  },
-                }
-              ]
-            ]
           }
         ]
+      ]
+    },
+    {
+      'target_name': 'libpng_static',
+      'type': 'static_library',
+      'standalone_static_library': 1,
+      'include_dirs': [
+        # Needed for generated pnglibconf.h and pngprefix.h
+        '../third_party/libpng',
+        '../third_party/externals/libpng',
+      ],
+      'dependencies': [
+        'zlib.gyp:zlib',
+      ],
+      'export_dependent_settings': [
+        'zlib.gyp:zlib',
+      ],
+      'direct_dependent_settings': {
+        'include_dirs': [
+          '../third_party/externals/libpng',
+          # Needed for generated pnglibconf.h and pngprefix.h
+          '../third_party/libpng',
+        ],
+        'defines': [
+          'SKIA_PNG_PREFIXED',
+        ],
+      },
+      'cflags': [
+        '-w',
+        '-fvisibility=hidden',
+      ],
+      'sources': [
+        '../third_party/externals/libpng/png.c',
+        '../third_party/externals/libpng/pngerror.c',
+        '../third_party/externals/libpng/pngget.c',
+        '../third_party/externals/libpng/pngmem.c',
+        '../third_party/externals/libpng/pngpread.c',
+        '../third_party/externals/libpng/pngread.c',
+        '../third_party/externals/libpng/pngrio.c',
+        '../third_party/externals/libpng/pngrtran.c',
+        '../third_party/externals/libpng/pngrutil.c',
+        '../third_party/externals/libpng/pngset.c',
+        '../third_party/externals/libpng/pngtrans.c',
+        '../third_party/externals/libpng/pngwio.c',
+        '../third_party/externals/libpng/pngwrite.c',
+        '../third_party/externals/libpng/pngwtran.c',
+        '../third_party/externals/libpng/pngwutil.c',
+      ],
+      'conditions': [
+        [ 'skia_os == "ios"', {
+          # explicitly disable looking for NEON on iOS builds
+          'defines': [
+            'PNG_ARM_NEON_OPT=0',
+          ],
+        }, { # skia_os != "ios" 
+          'dependencies': [
+            'libpng.gyp:libpng_static_neon',
+          ],
+        }],
       ],
     },
+    {
+      'target_name': 'libpng_static_neon',
+      'type': 'static_library',
+      'include_dirs': [
+        # Needed for generated pnglibconf.h and pngprefix.h
+        '../third_party/libpng',
+        '../third_party/externals/libpng',
+      ],
+      'dependencies': [
+        'zlib.gyp:zlib',
+      ],
+     'sources': [
+        '../third_party/externals/libpng/arm/arm_init.c',
+        '../third_party/externals/libpng/arm/filter_neon.S',
+        '../third_party/externals/libpng/arm/filter_neon_intrinsics.c',
+      ],
+      'conditions': [
+        ['arm_neon_optional', {
+          'cflags': [
+            '-mfpu=neon',
+          ],
+        }],
+      ],
+    }
   ]
 }