Fixes and livability improvements for LTO in Firefox 82 on ppc64le Linux. Read web page first! -- https://www.talospace.com/2020/10/firefox-82-on-power-goes-pgo.html

firefox82-lto-pgo.diff

diff -r 72f6df8e0ae6 build/moz.configure/lto-pgo.configure
--- a/build/moz.configure/lto-pgo.configure     Thu Oct 22 10:17:13 2020 +0000
+++ b/build/moz.configure/lto-pgo.configure     Mon Oct 26 19:48:07 2020 -0700
@@ -71,17 +71,17 @@
 @imports('multiprocessing')
 @imports(_from='__builtin__', _import='min')
 def pgo_flags(compiler, profdata, target_is_windows):
     if compiler.type == 'gcc':
         return namespace(
             gen_cflags=['-fprofile-generate'],
             gen_ldflags=['-fprofile-generate'],
             use_cflags=['-fprofile-use', '-fprofile-correction',
-                        '-Wcoverage-mismatch'],
+                        '-Wno-coverage-mismatch'],
             use_ldflags=['-fprofile-use'],
         )
 
     if compiler.type in ('clang-cl', 'clang'):
         prefix = ''
         if compiler.type == 'clang-cl':
             prefix = '/clang:'
             gen_ldflags = None
diff -r 72f6df8e0ae6 build/moz.configure/warnings.configure
--- a/build/moz.configure/warnings.configure    Thu Oct 22 10:17:13 2020 +0000
+++ b/build/moz.configure/warnings.configure    Mon Oct 26 19:48:07 2020 -0700
@@ -211,17 +211,17 @@
     # an error, which we would like to ignore. This seems to only affect the MinGW
     # build, but we're not sure why.
     check_and_add_gcc_warning('-Wno-enum-compare')
 
 # We hit this all over the place with the gtest INSTANTIATE_TEST_CASE_P macro
 check_and_add_gcc_warning('-Wno-gnu-zero-variadic-macro-arguments')
 
 # Make it an error to be missing function declarations.
-check_and_add_gcc_warning('-Werror=implicit-function-declaration')
+check_and_add_gcc_warning('-Werror=implicit-function-declaration', compiler=c_compiler)
 
 # New in clang 11. We can't really do anything about this warning.
 check_and_add_gcc_warning('-Wno-psabi')
 
 
 # Please keep these last in this file
 add_old_configure_assignment('_WARNINGS_CFLAGS', warnings_flags.cflags)
 add_old_configure_assignment('_WARNINGS_CXXFLAGS', warnings_flags.cxxflags)
diff -r 72f6df8e0ae6 build/pgo/profileserver.py
--- a/build/pgo/profileserver.py        Thu Oct 22 10:17:13 2020 +0000
+++ b/build/pgo/profileserver.py        Mon Oct 26 19:48:07 2020 -0700
@@ -191,16 +191,19 @@
 
         # Try to move the crash reports to the artifacts even if Firefox appears
         # to exit successfully, in case there's a crash that doesn't set the
         # return code to non-zero for some reason.
         if get_crashreports(profilePath, name='Firefox exited successfully?') != 0:
             print("Firefox exited successfully, but produced a crashreport")
             sys.exit(1)
 
+        os.system("/home/censored/src/mozilla-release/gccpgostub.csh")
+        sys.exit(0)
+
         llvm_profdata = env.get('LLVM_PROFDATA')
         if llvm_profdata:
             profraw_files = glob.glob('*.profraw')
             if not profraw_files:
                 print('Could not find profraw files in the current directory: %s' % os.getcwd())
                 sys.exit(1)
             merge_cmd = [
                 llvm_profdata,
diff -r 72f6df8e0ae6 mfbt/tests/moz.build
--- a/mfbt/tests/moz.build      Thu Oct 22 10:17:13 2020 +0000
+++ b/mfbt/tests/moz.build      Mon Oct 26 19:48:07 2020 -0700
@@ -71,19 +71,19 @@
     'TestWeakPtr',
     'TestWrappingOperations',
     'TestXorShift128PlusRNG',
 ])
 
 # Not to be unified with the rest, because this test
 # sets MOZ_PRETEND_NO_JSRUST, which changes the behavior
 # of the included headers.
-CppUnitTests([
-    'TestUtf8',
-])
+#CppUnitTests([
+#    'TestUtf8',
+#])
 
 if not CONFIG['MOZ_ASAN']:
     CppUnitTests([
         'TestPoisonArea',
     ])
 
 # Since we link directly with MFBT object files, define IMPL_MFBT
 DEFINES['IMPL_MFBT'] = True