--- firefox-19.0.2.ebuild	2013-03-30 23:28:31.018634903 +0100
+++ firefox-19.0.2.ebuild.new	2013-03-30 23:52:01.242004684 +0100
@@ -38,7 +38,7 @@
 KEYWORDS="~alpha ~amd64 ~arm ~ia64 ~ppc ~ppc64 ~x86 ~amd64-linux ~x86-linux"
 SLOT="0"
 LICENSE="MPL-2.0 GPL-2 LGPL-2.1"
-IUSE="bindist gstreamer +jit +minimal pgo selinux system-jpeg system-sqlite"
+IUSE="address-sanitizer bindist gstreamer +jit +minimal pgo selinux system-jpeg system-sqlite"
 
 # More URIs appended below...
 SRC_URI="${SRC_URI}
@@ -213,10 +213,53 @@
 	mozconfig_use_enable gstreamer
 	mozconfig_use_enable system-sqlite
 	mozconfig_use_with system-jpeg
+
 	# Feature is know to cause problems on hardened
 	mozconfig_use_enable jit methodjit
 	mozconfig_use_enable jit tracejit
 
+	# compiler-dependent settings
+	if [[ $(tc-getCC) =~ clang ]]; then
+		mozconfig_annotate 'from ebuild, CC=clang detected' --enable-llvm-hacks
+
+		# methodjit causes clang builds to segfault on x86_64 (see bug #462608)
+		if use amd64; then
+			sed -e '/javascript.options.methodjit/ s/true/false/' \
+				-i "${S}"/modules/libpref/src/init/all.js
+		fi
+
+		# https://developer.mozilla.org/en-US/docs/Building_Firefox_with_Address_Sanitizer
+		if use address-sanitizer; then
+			echo "export MOZ_JEMALLOC=0" >> ${S}/.mozconfig
+		    mozconfig_annotate '+address-sanitizer' --disable-crash-reporter
+		    mozconfig_annotate '+address-sanitizer' --disable-elf-hack
+		    mozconfig_annotate '+address-sanitizer' --disable-jemalloc
+		    mozconfig_annotate '+address-sanitizer' --disable-replace-malloc
+
+			echo "export MOZ_DEBUG_SYMBOLS=1" >> ${S}/.mozconfig
+		    mozconfig_use_enable address-sanitizer debug-symbols
+			mozconfig_use_enable address-sanitizer
+			append-flags "-fsanitize=address"
+			append-flags "-Dxmalloc=myxmalloc"
+		fi
+	else
+		use address-sanitizer && die "Use flag address-sanitizer can only be \
+			enabled if CC=clang is set. You're using a different compiler."
+
+		if [[ $(gcc-major-version) -lt 4 ]]; then
+			append-cxxflags -fno-stack-protector
+		elif [[ $(gcc-major-version) -gt 4 || $(gcc-minor-version) -gt 3 ]]; then
+			if use amd64 || use x86; then
+				append-flags -mno-avx
+			fi
+		fi
+	fi
+
+	# support EXTRA_ECONF, maybe this should be in mozcoreconf-2.eclass ..
+	for eeopt in $EXTRA_ECONF; do
+		mozconfig_annotate 'from ebuild, passed using EXTRA_ECONF' $eeopt
+	done
+
 	# Allow for a proper pgo build
 	if use pgo; then
 		echo "mk_add_options PROFILE_GEN_SCRIPT='\$(PYTHON) \$(OBJDIR)/_profile/pgo/profileserver.py'" >> "${S}"/.mozconfig
@@ -224,14 +267,6 @@
 
 	# Finalize and report settings
 	mozconfig_final
-
-	if [[ $(gcc-major-version) -lt 4 ]]; then
-		append-cxxflags -fno-stack-protector
-	elif [[ $(gcc-major-version) -gt 4 || $(gcc-minor-version) -gt 3 ]]; then
-		if use amd64 || use x86; then
-			append-flags -mno-avx
-		fi
-	fi
 }
 
 src_compile() {