Consume Hermes from local source directory (#38967)

Summary:
Pull Request resolved: #38967

Changelog: [IOS][Added] - Now it is possible to build Hermes form local source directory. Just set REACT_NATIVE_OVERRIDE_HERMES_DIR to the path to that directory.

Known shortcoming: changes made to the Hermes source will not be reflected in the RN project. You should manually delete `Pods/hermes-engine` and rerun `pod install`.

Reviewed By: cipolleschi

Differential Revision: D48121314

fbshipit-source-id: 0389662396921bdf120d390de36a586c52eb47f1

.gitignore

@@ -137,6 +137,7 @@ package-lock.json
 /packages/react-native/sdks/download
 /packages/react-native/sdks/hermes
 /packages/react-native/sdks/hermesc
+/packages/react-native/sdks/hermes-engine/hermes-engine-from-local-source-dir.tar.gz
 
 # Visual studio
 .vscode

packages/react-native/sdks/hermes-engine/hermes-engine.podspec

@@ -106,7 +106,7 @@ Pod::Spec.new do |spec|
           :script => <<-EOS
           . "${REACT_NATIVE_PATH}/scripts/xcode/with-environment.sh"
           export CMAKE_BINARY=${CMAKE_BINARY:-#{CMAKE_BINARY}}
-          . ${REACT_NATIVE_PATH}/sdks/hermes-engine/utils/build-hermesc-xcode.sh #{hermesc_path}
+          . ${REACT_NATIVE_PATH}/sdks/hermes-engine/utils/build-hermesc-xcode.sh #{hermesc_path} ${REACT_NATIVE_PATH}/ReactCommon/jsi
           EOS
         },
         {
@@ -118,7 +118,7 @@ Pod::Spec.new do |spec|
           :script => <<-EOS
           . "${REACT_NATIVE_PATH}/scripts/xcode/with-environment.sh"
           export CMAKE_BINARY=${CMAKE_BINARY:-#{CMAKE_BINARY}}
-          . ${REACT_NATIVE_PATH}/sdks/hermes-engine/utils/build-hermes-xcode.sh #{version} #{hermesc_path}/ImportHermesc.cmake
+          . ${REACT_NATIVE_PATH}/sdks/hermes-engine/utils/build-hermes-xcode.sh #{version} #{hermesc_path}/ImportHermesc.cmake ${REACT_NATIVE_PATH}/ReactCommon/jsi
           EOS
         }
       ]

packages/react-native/sdks/hermes-engine/hermes-utils.rb

@@ -15,13 +15,14 @@ module HermesEngineSourceType
     BUILD_FROM_GITHUB_COMMIT = :build_from_github_commit
     BUILD_FROM_GITHUB_TAG = :build_from_github_tag
     BUILD_FROM_GITHUB_MAIN = :build_from_github_main
+    BUILD_FROM_LOCAL_SOURCE_DIR = :build_from_local_source_dir
 
     def HermesEngineSourceType.isPrebuilt(source_type)
         return source_type == LOCAL_PREBUILT_TARBALL || source_type == DOWNLOAD_PREBUILD_RELEASE_TARBALL || source_type == DOWNLOAD_PREBUILT_NIGHTLY_TARBALL
     end
 
     def HermesEngineSourceType.isFromSource(source_type)
-        return source_type == BUILD_FROM_GITHUB_COMMIT || source_type == BUILD_FROM_GITHUB_TAG || source_type == BUILD_FROM_GITHUB_MAIN
+        return source_type == BUILD_FROM_GITHUB_COMMIT || source_type == BUILD_FROM_GITHUB_TAG || source_type == BUILD_FROM_GITHUB_MAIN || source_type == BUILD_FROM_LOCAL_SOURCE_DIR
     end
 end
 
@@ -40,6 +41,10 @@ def HermesEngineSourceType.isFromSource(source_type)
 
 # Returns: hermes-engine source type
 def hermes_source_type(version, react_native_path)
+    if override_hermes_dir_envvar_defined()
+        return HermesEngineSourceType::BUILD_FROM_LOCAL_SOURCE_DIR
+    end
+
     if hermes_engine_tarball_envvar_defined()
         return HermesEngineSourceType::LOCAL_PREBUILT_TARBALL
     end
@@ -67,6 +72,10 @@ def hermes_source_type(version, react_native_path)
     return HermesEngineSourceType::BUILD_FROM_GITHUB_MAIN
 end
 
+def override_hermes_dir_envvar_defined()
+    return ENV.has_key?('REACT_NATIVE_OVERRIDE_HERMES_DIR')
+end
+
 def hermes_engine_tarball_envvar_defined()
     return ENV.has_key?('HERMES_ENGINE_TARBALL_PATH')
 end
@@ -93,6 +102,8 @@ def nightly_artifact_exists(version)
 
 def podspec_source(source_type, version, react_native_path)
     case source_type
+    when HermesEngineSourceType::BUILD_FROM_LOCAL_SOURCE_DIR
+        return podspec_source_build_from_local_source_dir(react_native_path)
     when HermesEngineSourceType::LOCAL_PREBUILT_TARBALL
         return podspec_source_local_prebuilt_tarball()
     when HermesEngineSourceType::BUILD_FROM_GITHUB_COMMIT
@@ -110,6 +121,32 @@ def podspec_source(source_type, version, react_native_path)
     end
 end
 
+def podspec_source_build_from_local_source_dir(react_native_path)
+    source_dir_path = ENV['REACT_NATIVE_OVERRIDE_HERMES_DIR']
+    if Dir.exist?(source_dir_path)
+        hermes_log("Using source code from local path: #{source_dir_path}")
+        tarball_path = File.join(react_native_path, "sdks", "hermes-engine", "hermes-engine-from-local-source-dir.tar.gz")
+        exclude_paths = [
+            "__tests__",
+            "./external/flowtest",
+            "./external/esprima/test_fixtures"
+        ]
+        .map {|path| "--exclude=#{path}"}
+        .join(' ')
+        tar_command = "tar #{exclude_paths} -czvf #{tarball_path} -C #{source_dir_path} . 2> /dev/null"
+        success = system(tar_command)
+        if !success
+            abort "Failed to create a tarball with the contents of \"#{source_dir_path}\""
+        end
+        return {:http => "file://#{tarball_path}"}
+    else
+        abort <<-EOS
+        [Hermes] REACT_NATIVE_OVERRIDE_HERMES_DIR is set, but points to a non-existing directory: \"#{source_dir_path}\"
+        If you don't want to use local source, run `unset REACT_NATIVE_OVERRIDE_HERMES_DIR`
+        EOS
+    end
+end
+
 def podspec_source_local_prebuilt_tarball()
     tarball_path = ENV['HERMES_ENGINE_TARBALL_PATH']
     if File.exist?(tarball_path)

packages/react-native/sdks/hermes-engine/utils/build-hermes-xcode.sh

@@ -8,6 +8,7 @@ set -x
 
 release_version="$1"; shift
 hermesc_path="$1"; shift
+jsi_path="$1"; shift
 
 enable_debugger="false"
 if [[ "$CONFIGURATION" == "Debug" ]]; then
@@ -47,6 +48,7 @@ echo "Configure Apple framework"
   -DHERMES_BUILD_APPLE_FRAMEWORK:BOOLEAN=true \
   -DHERMES_BUILD_APPLE_DSYM:BOOLEAN=true \
   -DIMPORT_HERMESC:PATH="${hermesc_path}" \
+  -DJSI_DIR="$jsi_path" \
   -DHERMES_RELEASE_VERSION="for RN $release_version" \
   -DCMAKE_BUILD_TYPE="$cmake_build_type"
 

packages/react-native/sdks/hermes-engine/utils/build-hermesc-xcode.sh

@@ -6,7 +6,8 @@
 
 set -x
 
-hermesc_dir_path="$1"
+hermesc_dir_path="$1"; shift
+jsi_path="$1"
 
 # This script is supposed to be executed from Xcode "run script" phase.
 # Xcode sets up its build environment based on the build target.
@@ -17,7 +18,7 @@ export MACOSX_DEPLOYMENT_TARGET=$MACOSX_DEPLOYMENT_TARGET
 SDKROOT=$(xcode-select -p)/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk
 export SDKROOT=$SDKROOT
 
-if ! "$CMAKE_BINARY" -S "${PODS_ROOT}/hermes-engine" -B "$hermesc_dir_path"
+if ! "$CMAKE_BINARY" -S "${PODS_ROOT}/hermes-engine" -B "$hermesc_dir_path" -DJSI_DIR="$jsi_path"
 then
     echo "Failed to configure Hermesc cmake project."
     exit 1