browser(firefox): use pre-downloaded toolchains for release builds

Firefox requires a bunch of build tools (aka "toolchains") to be built.
Until recently, default MacOS clang (that comes with Xcode) was
sufficient to compile firefox.

However, Firefox 95 started to use WebAssembly. This yielded the following issues specific to MacOS (somehow builds complete successfully on other platforms):

- Default MacOS clang that comes with XCode doesn't support WebAssembly: WebAssembly/wasi-sdk#172 (comment)
- Clang that comes from Homebrew is missing `libclang_rt.builtins-wasm32.a`: https://github.com/jedisct1/libclang_rt.builtins-wasm32.a/blob/79b9b39f9be950110d3a7d6f91d86074349d8302/README.md
- Firefox also requires `wasi sysroot`

Now, depending on which branch firefox checkout comes from
(`mozilla-release` vs `mozilla-beta`), firefox build system **might** or
**might not** be able to download all the required toolchains in the
`$HOME/.mozbuild` folder:
- `mozilla-beta` branch supports toolchain auto-download
- `mozilla-release` **does not** support it yet: https://bugzilla.mozilla.org/show_bug.cgi?id=1744197#c2

The recommended solution is to download toolchains using non-release
firefox branch, and then re-use these toolchains to compile firefox from
release branch.

This patch does exactly this: relies on pre-downloaded toolchains for
release firefox compilation. To re-use pre-downloaded toolchains, we set a
combination of `MOZ_AUTOMATION` and `MOZ_FETCH_DIR` environment
variables - this is the same approach that is used on the official
Firefox CI (see `about:buildconfig` page in the stable firefox 95).

This almost works, but there's a catch: the `MOZ_AUTOMATION` environment
variable auto-adds ("implies") the `--enable-release` configuration
option: https://github.com/mozilla/gecko-dev/blob/9e1cd985485c0e01c5faa9b5072a405b344ebde7/moz.configure#L162

The `--enable-release` is supposed to yield a better binary, and we want
builds to be the same across platforms, so this patch adds this option
**unconditionally on all platforms**.

The `--enable-release` is also more picky about the source code: for
example, it complains about unused return values. Browser changes in
this patch are addressing these.

References microsoft#10759

browser_patches/firefox-beta/BUILD_NUMBER

@@ -1,2 +1,2 @@
-1310
-Changed: lushnikov@chromium.org Tue Dec 14 15:56:05 PST 2021
+1311
+Changed: lushnikov@chromium.org Tue Dec 14 23:27:53 PST 2021

browser_patches/firefox-beta/build.sh

@@ -63,6 +63,8 @@ echo "ac_add_options --disable-backgroundtasks" >> .mozconfig
 if [[ -n $FF_DEBUG_BUILD ]]; then
   echo "ac_add_options --enable-debug" >> .mozconfig
   echo "ac_add_options --enable-debug-symbols" >> .mozconfig
+else
+  echo "ac_add_options --enable-release" >> .mozconfig
 fi
 
 if [[ "$(uname)" == MINGW* || "$(uname)" == "Darwin" ]]; then
@@ -86,7 +88,7 @@ if [[ $1 != "--juggler" ]]; then
   fi
 fi
 
-if [[ $1 == "--full" || $2 == "--full" ]]; then
+if [[ $1 == "--full" || $2 == "--full" || $1 == "--bootstrap" ]]; then
   echo "ac_add_options --enable-bootstrap" >> .mozconfig
   if [[ "$(uname)" == "Darwin" || "$(uname)" == "Linux" ]]; then
     SHELL=/bin/sh ./mach --no-interactive bootstrap --application-choice=browser
@@ -103,13 +105,15 @@ fi
 
 if [[ $1 == "--juggler" ]]; then
   ./mach build faster
+elif [[ $1 == "--bootstrap" ]]; then
+  ./mach configure
 else
   ./mach build
+  if [[ "$(uname)" == "Darwin" ]]; then
+    node "${SCRIPT_FOLDER}"/install-preferences.js "$PWD"/${OBJ_FOLDER}/dist
+  else
+    node "${SCRIPT_FOLDER}"/install-preferences.js "$PWD"/${OBJ_FOLDER}/dist/bin
+  fi
 fi
 
-if [[ "$(uname)" == "Darwin" ]]; then
-  node "${SCRIPT_FOLDER}"/install-preferences.js "$PWD"/${OBJ_FOLDER}/dist
-else
-  node "${SCRIPT_FOLDER}"/install-preferences.js "$PWD"/${OBJ_FOLDER}/dist/bin
-fi
 

browser_patches/firefox-beta/patches/bootstrap.diff

@@ -1863,7 +1863,7 @@ index b32d426ba38045d14e6f1e79d17e8e6061e78227..df782034e79466fcc251e9a06e99d2e1
    }
 
 diff --git a/js/src/vm/DateTime.cpp b/js/src/vm/DateTime.cpp
-index e8f27fb69691aa6062c860a14ec94660fb9e5189..67715cbbc8257f11927564b45bbc8ee5384f809d 100644
+index e8f27fb69691aa6062c860a14ec94660fb9e5189..83cffc97f12072c24a7ea1bbd7b26ee37d856df3 100644
 --- a/js/src/vm/DateTime.cpp
 +++ b/js/src/vm/DateTime.cpp
 @@ -170,6 +170,11 @@ void js::DateTimeInfo::internalResetTimeZone(ResetTimeZoneMode mode) {
@@ -1903,13 +1903,16 @@ index e8f27fb69691aa6062c860a14ec94660fb9e5189..67715cbbc8257f11927564b45bbc8ee5
  #if JS_HAS_INTL_API
  #  if defined(XP_WIN)
  static bool IsOlsonCompatibleWindowsTimeZoneId(std::string_view tz) {
-@@ -719,9 +738,14 @@ void js::ResyncICUDefaultTimeZone() {
+@@ -719,9 +738,17 @@ void js::ResyncICUDefaultTimeZone() {
 
  void js::DateTimeInfo::internalResyncICUDefaultTimeZone() {
  #if JS_HAS_INTL_API
 +  if (!timeZoneOverride_.empty()) {
 +    mozilla::Span<const char> tzid = mozilla::Span(timeZoneOverride_.data(), timeZoneOverride_.length());
-+    mozilla::intl::TimeZone::SetDefaultTimeZone(tzid);
++    auto result = mozilla::intl::TimeZone::SetDefaultTimeZone(tzid);
++    if (result.isErr()) {
++      fprintf(stderr, "ERROR: failed to setup default time zone\n");
++    }
 +    return;
 +  }
 +

browser_patches/firefox/BUILD_NUMBER

@@ -1,2 +1,2 @@
-1310
-Changed: lushnikov@chromium.org Mon 13 Dec 2021 07:00:27 PM PST
+1311
+Changed: lushnikov@chromium.org Tue Dec 14 23:26:10 PST 2021

browser_patches/firefox/build.sh

@@ -62,6 +62,9 @@ echo "ac_add_options --disable-backgroundtasks" >> .mozconfig
 
 if [[ -n $FF_DEBUG_BUILD ]]; then
   echo "ac_add_options --enable-debug" >> .mozconfig
+  echo "ac_add_options --enable-debug-symbols" >> .mozconfig
+else
+  echo "ac_add_options --enable-release" >> .mozconfig
 fi
 
 if [[ "$(uname)" == MINGW* || "$(uname)" == "Darwin" ]]; then
@@ -89,25 +92,7 @@ if [[ $1 == "--full" || $2 == "--full" ]]; then
   if [[ "$(uname)" == "Darwin" || "$(uname)" == "Linux" ]]; then
     SHELL=/bin/sh ./mach --no-interactive bootstrap --application-choice=browser
   fi
-  if [[ "$(uname)" == "Darwin" ]]; then
-    HOMEBREW_LLVM="/opt/homebrew/opt/llvm/bin/clang";
-    if [[ ! -f "${HOMEBREW_LLVM}" || $($HOMEBREW_LLVM --version) != *"version 13"* ]]; then
-      echo "ERROR: as of Dec, 2021, building release firefox requires HomeBrew LLVM v13"
-      echo "Please run:"
-      echo
-      echo "    brew install llvm@13"
-      echo
-      exit 1
-    fi
-    echo "CC=${HOMEBREW_LLVM}" >> .mozconfig
-    echo "CXX=${HOMEBREW_LLVM}++" >> .mozconfig
-
-    # Download wasi toolchain if needed
-    if [[ ! -d "$HOME/.mozbuild/sysroot-wasm32-wasi" ]]; then
-      ./mach artifact toolchain --from-build toolchain-sysroot-wasm32-wasi
-      mv ./sysroot-wasm32-wasi ~/.mozbuild/
-    fi
-  elif [[ "$(uname)" == "Linux" ]]; then
+  if [[ "$(uname)" == "Linux" ]]; then
     echo "ac_add_options --enable-bootstrap" >> .mozconfig
   fi
   if [[ ! -z "${WIN32_REDIST_DIR}" ]]; then
@@ -116,6 +101,22 @@ if [[ $1 == "--full" || $2 == "--full" ]]; then
   fi
 fi
 
+if [[ "$(uname)" == "Darwin" ]]; then
+  if [[ ! -d "$HOME/.mozbuild/clang" ]]; then
+    echo "ERROR: build toolchains are not found, specifically \$HOME/.mozbuild/clang is not there!"
+    echo "Since December, 2021, release build toolchains cannot be downloaded automatically. See:"
+    echo "   https://bugzilla.mozilla.org/show_bug.cgi?id=1744197#c2"
+    echo
+    echo "To bootstrap toolchains:"
+    echo "    ./browser_patches/prepare_checkout.sh firefox-beta"
+    echo "    ./browser_patches/build.sh firefox-beta --bootstrap"
+    echo
+    exit 1
+  fi
+  export MOZ_AUTOMATION=1
+  export MOZ_FETCHES_DIR=$HOME/.mozbuild
+fi
+
 if ! [[ -f "$HOME/.mozbuild/_virtualenvs/mach/bin/python" ]]; then
   ./mach create-mach-environment
 fi

browser_patches/firefox/patches/bootstrap.diff

@@ -1871,7 +1871,7 @@ index b32d426ba38045d14e6f1e79d17e8e6061e78227..df782034e79466fcc251e9a06e99d2e1
    }
 
 diff --git a/js/src/vm/DateTime.cpp b/js/src/vm/DateTime.cpp
-index e8f27fb69691aa6062c860a14ec94660fb9e5189..67715cbbc8257f11927564b45bbc8ee5384f809d 100644
+index e8f27fb69691aa6062c860a14ec94660fb9e5189..83cffc97f12072c24a7ea1bbd7b26ee37d856df3 100644
 --- a/js/src/vm/DateTime.cpp
 +++ b/js/src/vm/DateTime.cpp
 @@ -170,6 +170,11 @@ void js::DateTimeInfo::internalResetTimeZone(ResetTimeZoneMode mode) {
@@ -1911,13 +1911,16 @@ index e8f27fb69691aa6062c860a14ec94660fb9e5189..67715cbbc8257f11927564b45bbc8ee5
  #if JS_HAS_INTL_API
  #  if defined(XP_WIN)
  static bool IsOlsonCompatibleWindowsTimeZoneId(std::string_view tz) {
-@@ -719,9 +738,14 @@ void js::ResyncICUDefaultTimeZone() {
+@@ -719,9 +738,17 @@ void js::ResyncICUDefaultTimeZone() {
 
  void js::DateTimeInfo::internalResyncICUDefaultTimeZone() {
  #if JS_HAS_INTL_API
 +  if (!timeZoneOverride_.empty()) {
 +    mozilla::Span<const char> tzid = mozilla::Span(timeZoneOverride_.data(), timeZoneOverride_.length());
-+    mozilla::intl::TimeZone::SetDefaultTimeZone(tzid);
++    auto result = mozilla::intl::TimeZone::SetDefaultTimeZone(tzid);
++    if (result.isErr()) {
++      fprintf(stderr, "ERROR: failed to setup default time zone\n");
++    }
 +    return;
 +  }
 +
@@ -2559,7 +2562,7 @@ diff --git a/widget/cocoa/NativeKeyBindings.mm b/widget/cocoa/NativeKeyBindings.
 index 2b11df66d9445080d4d8a19a915b3e00285c5d32..caef1b65bbcff899f45c3e3cddfe76e88479ec30 100644
 --- a/widget/cocoa/NativeKeyBindings.mm
 +++ b/widget/cocoa/NativeKeyBindings.mm
-@@ -491,6 +491,13 @@ void NativeKeyBindings::GetEditCommandsForTests(NativeKeyBindingsType aType,
+@@ -491,6 +491,13 @@
        break;
      case KEY_NAME_INDEX_ArrowLeft:
        if (aEvent.IsAlt()) {
@@ -2573,7 +2576,7 @@ index 2b11df66d9445080d4d8a19a915b3e00285c5d32..caef1b65bbcff899f45c3e3cddfe76e8
          break;
        }
        if (aEvent.IsMeta() || (aEvent.IsControl() && aEvent.IsShift())) {
-@@ -511,6 +518,13 @@ void NativeKeyBindings::GetEditCommandsForTests(NativeKeyBindingsType aType,
+@@ -511,6 +518,13 @@
        break;
      case KEY_NAME_INDEX_ArrowRight:
        if (aEvent.IsAlt()) {
@@ -2587,7 +2590,7 @@ index 2b11df66d9445080d4d8a19a915b3e00285c5d32..caef1b65bbcff899f45c3e3cddfe76e8
          break;
        }
        if (aEvent.IsMeta() || (aEvent.IsControl() && aEvent.IsShift())) {
-@@ -531,6 +545,10 @@ void NativeKeyBindings::GetEditCommandsForTests(NativeKeyBindingsType aType,
+@@ -531,6 +545,10 @@
        break;
      case KEY_NAME_INDEX_ArrowUp:
        if (aEvent.IsControl()) {
@@ -2598,7 +2601,7 @@ index 2b11df66d9445080d4d8a19a915b3e00285c5d32..caef1b65bbcff899f45c3e3cddfe76e8
          break;
        }
        if (aEvent.IsMeta()) {
-@@ -540,7 +558,7 @@ void NativeKeyBindings::GetEditCommandsForTests(NativeKeyBindingsType aType,
+@@ -540,7 +558,7 @@
          instance->AppendEditCommandsForSelector(
              !aEvent.IsShift()
                  ? ToObjcSelectorPtr(@selector(moveToBeginningOfDocument:))
@@ -2607,7 +2610,7 @@ index 2b11df66d9445080d4d8a19a915b3e00285c5d32..caef1b65bbcff899f45c3e3cddfe76e8
              aCommands);
          break;
        }
-@@ -563,6 +581,10 @@ void NativeKeyBindings::GetEditCommandsForTests(NativeKeyBindingsType aType,
+@@ -563,6 +581,10 @@
        break;
      case KEY_NAME_INDEX_ArrowDown:
        if (aEvent.IsControl()) {