bug 1481614 - detect icecream usage in build telemetry. r=chmanchester,glandium

This patch adds detection for when icecream is in use to build telemetry.
icecream is commonly enabled in two ways: by either setting CC/CXX to point
to icecream's cc/c++ symlinks, or by setting adding
mk_add_options 'export CCACHE_PREFIX=icecc' to a mozconfig when also using
ccache. For the former, this patch adds a simple configure check to see
if CXX is a symlink to a file named 'icecc'. For the latter this patch adds
CCACHE_PREFIX as a configure subst to capture the value.

We don't currently have a facility for writing telemetry tests that depend on
configure values. Local manual testing shows that it does work as expected.

Differential Revision: https://phabricator.services.mozilla.com/D18138

--HG--
extra : moz-landing-system : lando

build/moz.configure/toolchain.configure

@@ -322,6 +322,12 @@ def ccache(value):
 
 ccache = check_prog('CCACHE', progs=(), input=ccache)
 
+js_option(env='CCACHE_PREFIX',
+          nargs=1,
+          help='Compiler prefix to use when using ccache')
+
+set_config('CCACHE_PREFIX', depends_if('CCACHE_PREFIX')(lambda prefix: prefix[0]))
+
 # Distinguish ccache from sccache.
 
 
@@ -1221,6 +1227,15 @@ host_cxx_compiler = compiler('C++', host, c_compiler=host_c_compiler,
 building_with_gcc = depends(c_compiler)(lambda info: info.type == 'gcc')
 
 
+@depends(cxx_compiler)
+@imports('os')
+def cxx_is_icecream(info):
+    if (os.path.islink(info.compiler) and os.path.basename(
+            os.readlink(info.compiler)) == 'icecc'):
+        return True
+set_config('CXX_IS_ICECREAM', cxx_is_icecream)
+
+
 @depends(c_compiler)
 def msvs_version(info):
     # clang-cl emulates the same version scheme as cl. And MSVS_VERSION needs to

config/config.mk

@@ -271,6 +271,10 @@ export CCACHE_CPP2=1
 endif
 endif
 
+ifdef CCACHE_PREFIX
+export CCACHE_PREFIX
+endif
+
 # Set link flags according to whether we want a console.
 ifeq ($(OS_ARCH),WINNT)
 ifdef MOZ_WINCONSOLE

python/mozbuild/mozbuild/telemetry.py

@@ -209,12 +209,16 @@ def get_build_opts(substs):
                 ('opt', 'MOZ_OPTIMIZE', bool),
                 ('ccache', 'CCACHE', bool),
                 ('sccache', 'MOZ_USING_SCCACHE', bool),
-                # TODO: detect icecream: https://bugzilla.mozilla.org/show_bug.cgi?id=1481614
             )
         }
         compiler = substs.get('CC_TYPE', None)
         if compiler:
             opts['compiler'] = str(compiler)
+        # icecream may be enabled by setting CC/CXX to symlinks to icecc,
+        # or if using it together with ccache by setting CCACHE_PREFIX=icecc.
+        prefix = os.path.basename(substs.get('CCACHE_PREFIX', ''))
+        if substs.get('CXX_IS_ICECREAM', None) or prefix == 'icecc':
+            opts['icecream'] = True
         return opts
     except BuildEnvironmentNotFoundException:
         return {}