Add --enable-shared option to iosbuild.sh to build dynamic framework

Also allows use of --enable-shared when configuring for Mac OS X,
producing a bare .dylib.

Enabling the shared framework bumps the iOS deployment target to 8.0,
the minimum required to support dynamic framework deployment in apps.

When not using --enable-shared, a static library for iOS 6.0+ will still
be built.

Minimum version settings have been moved into ios-version.sh so they
can be updated in a single place.

As with the static build, unless header search paths are manually
tweaked, users must add a VPX prefix on includes, such as:

  #include <VPX/vpx/vpx_decoder.h>

A module map for headers is not yet included as inttypes.h is not
modular; this means that VPX cannot be used directly in Swift code,
but can still be pulled in through an Objective-C wrapper.

BUG=https://bugs.chromium.org/p/webm/issues/detail?id=1092
Change-Id: I28fb06ce65e48ed167a88c14a7bfb2861989317e

build/make/configure.sh

@@ -751,7 +751,13 @@ process_common_toolchain() {
   enabled shared && soft_enable pic
 
   # Minimum iOS version for all target platforms (darwin and iphonesimulator).
-  IOS_VERSION_MIN="6.0"
+  if enabled shared; then
+    IOS_VERSION_OPTIONS="--enable-shared"
+  else
+    IOS_VERSION_OPTIONS=""
+  fi
+  IOS_VERSION_MIN=$("${source_path}/build/make/ios-version.sh" \
+    ${IOS_VERSION_OPTIONS})
 
   # Handle darwin variants. Newer SDKs allow targeting older
   # platforms, so use the newest one available.

build/make/ios-Info.plist

@@ -0,0 +1,35 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+	<key>CFBundleDevelopmentRegion</key>
+	<string>en</string>
+	<key>CFBundleExecutable</key>
+	<string>VPX</string>
+	<key>CFBundleIdentifier</key>
+	<string>org.webmproject.VPX</string>
+	<key>CFBundleInfoDictionaryVersion</key>
+	<string>6.0</string>
+	<key>CFBundleName</key>
+	<string>VPX</string>
+	<key>CFBundlePackageType</key>
+	<string>FMWK</string>
+	<key>CFBundleShortVersionString</key>
+	<string>${VERSION}</string>
+	<key>CFBundleSignature</key>
+	<string>????</string>
+	<key>CFBundleSupportedPlatforms</key>
+	<array>
+		<string>iPhoneOS</string>
+	</array>
+	<key>CFBundleVersion</key>
+	<string>${VERSION}</string>
+	<key>MinimumOSVersion</key>
+	<string>${IOS_VERSION_MIN}</string>
+	<key>UIDeviceFamily</key>
+	<array>
+		<integer>1</integer>
+		<integer>2</integer>
+	</array>
+</dict>
+</plist>

build/make/ios-version.sh

@@ -0,0 +1,17 @@
+#!/bin/sh
+##
+##  Copyright (c) 2016 The WebM project authors. All Rights Reserved.
+##
+##  Use of this source code is governed by a BSD-style license
+##  that can be found in the LICENSE file in the root of the source
+##  tree. An additional intellectual property rights grant can be found
+##  in the file PATENTS.  All contributing project authors may
+##  be found in the AUTHORS file in the root of the source tree.
+##
+
+if [ "$1" = "--enable-shared" ]; then
+  # Shared library framework builds are only possible on iOS 8 and later.
+  echo "8.0"
+else
+  echo "6.0"
+fi

build/make/iosbuild.sh

@@ -196,7 +196,12 @@ build_framework() {
   for target in ${targets}; do
     build_target "${target}"
     target_dist_dir="${BUILD_ROOT}/${target}/${DIST_DIR}"
-    lib_list="${lib_list} ${target_dist_dir}/lib/libvpx.a"
+    if [ "${ENABLE_SHARED}" = "yes" ]; then
+      local suffix="dylib"
+    else
+      local suffix="a"
+    fi
+    lib_list="${lib_list} ${target_dist_dir}/lib/libvpx.${suffix}"
   done
 
   cd "${ORIG_PWD}"
@@ -215,6 +220,17 @@ build_framework() {
   # Copy in vpx_version.h.
   cp -p "${BUILD_ROOT}/${target}/vpx_version.h" "${HEADER_DIR}"
 
+  if [ "${ENABLE_SHARED}" = "yes" ]; then
+    # Adjust the dylib's name so dynamic linking in apps works as expected.
+    install_name_tool -id '@rpath/VPX.framework/VPX' ${FRAMEWORK_DIR}/VPX
+
+    # Copy in Info.plist.
+    cat "${SCRIPT_DIR}/ios-Info.plist" \
+      | sed "s/\${VERSION}/${VERSION}/g" \
+      | sed "s/\${IOS_VERSION_MIN}/${IOS_VERSION_MIN}/g" \
+      > "${FRAMEWORK_DIR}/Info.plist"
+  fi
+
   # Confirm VPX.framework/VPX contains the targets requested.
   verify_framework_targets ${targets}
 
@@ -252,6 +268,7 @@ iosbuild_usage() {
 cat << EOF
   Usage: ${0##*/} [arguments]
     --help: Display this message and exit.
+    --enable-shared: Build a dynamic framework for use on iOS 8 or later.
     --extra-configure-args <args>: Extra args to pass when configuring libvpx.
     --macosx: Uses darwin15 targets instead of iphonesimulator targets for x86
               and x86_64. Allows linking to framework when builds target MacOSX
@@ -290,6 +307,9 @@ while [ -n "$1" ]; do
       iosbuild_usage
       exit
       ;;
+    --enable-shared)
+      ENABLE_SHARED=yes
+      ;;
     --preserve-build-output)
       PRESERVE_BUILD_OUTPUT=yes
       ;;
@@ -317,6 +337,19 @@ while [ -n "$1" ]; do
   shift
 done
 
+if [ "${ENABLE_SHARED}" = "yes" ]; then
+  CONFIGURE_ARGS="--enable-shared ${CONFIGURE_ARGS}"
+fi
+
+VERSION=$("${SCRIPT_DIR}"/version.sh --bare "${LIBVPX_SOURCE_DIR}" \
+  | sed -E 's/^v(.*)$/\1/')
+if [ "$ENABLE_SHARED" = "yes" ]; then
+  IOS_VERSION_OPTIONS="--enable-shared"
+else
+  IOS_VERSION_OPTIONS=""
+fi
+IOS_VERSION_MIN=$("${SCRIPT_DIR}/ios-version.sh" ${IOS_VERSION_OPTIONS})
+
 if [ "${VERBOSE}" = "yes" ]; then
 cat << EOF
   BUILD_ROOT=${BUILD_ROOT}
@@ -332,8 +365,12 @@ cat << EOF
   ORIG_PWD=${ORIG_PWD}
   PRESERVE_BUILD_OUTPUT=${PRESERVE_BUILD_OUTPUT}
   TARGETS="$(print_list "" ${TARGETS})"
+  ENABLE_SHARED=${ENABLE_SHARED}
   OSX_TARGETS="${OSX_TARGETS}"
   SIM_TARGETS="${SIM_TARGETS}"
+  SCRIPT_DIR="${SCRIPT_DIR}"
+  VERSION="${VERSION}"
+  IOS_VERSION_MIN="${IOS_VERSION_MIN}"
 EOF
 fi
 

configure

@@ -515,13 +515,18 @@ process_detect() {
         # Can only build shared libs on a subset of platforms. Doing this check
         # here rather than at option parse time because the target auto-detect
         # magic happens after the command line has been parsed.
-        if ! enabled linux && ! enabled os2; then
+        case "${tgt_os}" in
+        linux|os2|darwin*|iphonesimulator*)
+            # Supported platforms
+            ;;
+        *)
             if enabled gnu; then
                 echo "--enable-shared is only supported on ELF; assuming this is OK"
             else
-                die "--enable-shared only supported on ELF and OS/2 for now"
+                die "--enable-shared only supported on ELF, OS/2, and Darwin for now"
             fi
-        fi
+            ;;
+        esac
     fi
     if [ -z "$CC" ] || enabled external_build; then
         echo "Bypassing toolchain for environment detection."

libs.mk

@@ -273,6 +273,12 @@ EXPORT_FILE             := libvpx.syms
 LIBVPX_SO_SYMLINKS      := $(addprefix $(LIBSUBDIR)/, \
                              libvpx.dylib  )
 else
+ifeq ($(filter iphonesimulator%,$(TGT_OS)),$(TGT_OS))
+LIBVPX_SO               := libvpx.$(SO_VERSION_MAJOR).dylib
+SHARED_LIB_SUF          := .dylib
+EXPORT_FILE             := libvpx.syms
+LIBVPX_SO_SYMLINKS      := $(addprefix $(LIBSUBDIR)/, libvpx.dylib)
+else
 ifeq ($(filter os2%,$(TGT_OS)),$(TGT_OS))
 LIBVPX_SO               := libvpx$(SO_VERSION_MAJOR).dll
 SHARED_LIB_SUF          := _dll.a
@@ -288,6 +294,7 @@ LIBVPX_SO_SYMLINKS      := $(addprefix $(LIBSUBDIR)/, \
                              libvpx.so.$(SO_VERSION_MAJOR).$(SO_VERSION_MINOR))
 endif
 endif
+endif
 
 LIBS-$(CONFIG_SHARED) += $(BUILD_PFX)$(LIBVPX_SO)\
                            $(notdir $(LIBVPX_SO_SYMLINKS)) \