Enable Clang's -ftrivial-auto-var-init=zero on supported kernels

Signed-off-by: Tad <tad@spotco.us>

Patches/Common/android_kernel_common/0001-auto_var_init.patch

@@ -0,0 +1,22 @@
+From 919a61dedb0458ebd52291cb6d4948446fad4b44 Mon Sep 17 00:00:00 2001
+From: Daniel Micay <danielmicay@gmail.com>
+Date: Wed, 8 Apr 2020 11:10:43 -0400
+Subject: [PATCH] enable -ftrivial-auto-var-init=zero
+
+---
+ Makefile | 2 ++
+ 1 file changed, 2 insertions(+)
+
+diff --git a/Makefile b/Makefile
+index 79e2a78a7e92..abc66c11c84a 100644
+--- a/Makefile
++++ b/Makefile
+@@ -770,6 +770,8 @@ KBUILD_CFLAGS	+= -fomit-frame-pointer
+ endif
+ endif
+ 
++KBUILD_CFLAGS += -ftrivial-auto-var-init=zero -enable-trivial-auto-var-init-zero-knowing-it-will-be-removed-from-clang
++
+ KBUILD_CFLAGS   += $(call cc-option, -fno-var-tracking-assignments)
+ 
+ ifdef CONFIG_DEBUG_INFO

Scripts/Common/Functions.sh

@@ -536,6 +536,41 @@ hardenBootArgs() {
 }
 export -f hardenBootArgs;
 
+enableAutoVarInit() {
+	cd "$DOS_BUILD_BASE";
+	for kernel in "${DOS_AUTOVARINIT_KERNELS[@]}"
+	do
+		if [ -d "$DOS_BUILD_BASE/kernel/$kernel" ]; then
+			cd "$DOS_BUILD_BASE/kernel/$kernel";
+			if git apply --check "$DOS_PATCHES_COMMON/android_kernel_common/0001-auto_var_init.patch" &> /dev/null; then
+				if git apply "$DOS_PATCHES_COMMON/android_kernel_common/0001-auto_var_init.patch" &> /dev/null; then #(GrapheneOS)
+					echo "auto-var-init: Enabled for $kernel";
+				else
+					echo "auto-var-init: Failed to enable for $kernel";
+				fi;
+			elif git apply --check --reverse "$DOS_PATCHES_COMMON/android_kernel_common/0001-auto_var_init.patch" &> /dev/null; then
+				echo "auto-var-init: Already enabled for $kernel";
+			elif grep -q "trivial-auto-var-init=pattern" Makefile; then
+				sed -i 's/ftrivial-auto-var-init=pattern/ftrivial-auto-var-init=zero -enable-trivial-auto-var-init-zero-knowing-it-will-be-removed-from-clang/' Makefile; #(GrapheneOS)
+				grep -q "trivial-auto-var-init=pattern" Makefile;
+				if [ $? -eq 0 ]; then
+					echo "auto-var-init: Failed to switch from pattern to zero on $kernel";
+				else
+					echo "auto-var-init: Switched from pattern to zero on $kernel";
+				fi;
+			elif grep -q "trivial-auto-var-init=zero" Makefile; then
+				echo "auto-var-init: Already enabled for $kernel";
+			else
+				echo "auto-var-init: Could not enable for $kernel";
+			fi;
+#		else
+#			echo "auto-var-init: $kernel not in tree";
+		fi;
+	done;
+	cd "$DOS_BUILD_BASE";
+}
+export -f enableAutoVarInit;
+
 disableEnforceRRO() {
 	cd "$DOS_BUILD_BASE$1";
 	awk -i inplace '!/PRODUCT_ENFORCE_RRO_TARGETS .= framework-res/' *.mk &>/dev/null || true;

Scripts/LineageOS-17.1/Patch.sh

@@ -482,6 +482,7 @@ if [ "$DOS_GRAPHENE_EXEC" = true ]; then find "device" -maxdepth 2 -mindepth 2 -
 cd "$DOS_BUILD_BASE";
 deblobAudio;
 removeBuildFingerprints;
+enableAutoVarInit;
 
 #Tweaks for <2GB RAM devices
 #enableLowRam "device/motorola/harpia";

Scripts/LineageOS-18.1/Patch.sh

@@ -576,6 +576,7 @@ if [ "$DOS_GRAPHENE_EXEC" = true ]; then find "device" -maxdepth 2 -mindepth 2 -
 cd "$DOS_BUILD_BASE";
 deblobAudio;
 removeBuildFingerprints;
+enableAutoVarInit;
 
 #Tweaks for <2GB RAM devices
 #enableLowRam "device/samsung/serrano3gxx";

Scripts/init.sh

@@ -78,6 +78,7 @@ export DOS_SENSORS_PERM_NEW=true;
 export DOS_STRONG_ENCRYPTION_ENABLED=false; #Set true to enable AES 256-bit FDE encryption on 14.1+15.1 XXX: THIS WILL **DESTROY** EXISTING INSTALLS!
 export DOS_WEBVIEW_LFS=true; #Whether to `git lfs pull` in the WebView repository
 #alias DOS_WEBVIEW_CHERRYPICK='git pull "https://github.com/LineageOS/android_external_chromium-webview" refs/changes/00/316600/2';
+export DOS_AUTOVARINIT_KERNELS=('essential/msm8998' 'fxtec/msm8998' 'google/coral' 'google/msm-4.9' 'google/redbull' 'google/sunfish' 'google/wahoo' 'oneplus/msm8996' 'oneplus/msm8998' 'oneplus/sdm845' 'oneplus/sm7250' 'oneplus/sm8150' 'razer/msm8998' 'razer/sdm845' 'sony/sdm660' 'sony/sdm845' 'xiaomi/sdm660' 'xiaomi/sdm845' 'xiaomi/sm6150' 'xiaomi/sm8150' 'xiaomi/sm8250' 'zuk/msm8996');
 
 #Servers
 export DOS_DEFAULT_DNS_PRESET="Quad9"; #Sets default DNS. Options: See changeDefaultDNS() in Scripts/Common/Functions.sh