From fa00dfda13aaf8132bb6e3ae65e0e2adce9939a0 Mon Sep 17 00:00:00 2001
From: Rahul Chaudhry <rahulchaudhry@google.com>
Date: Wed, 21 Mar 2018 11:50:36 -0700
Subject: [PATCH] Disable relocation_packer and migrate to SHT_RELR sections.

Proposal for adding SHT_RELR sections in the generic-abi is at
https://groups.google.com/forum/#!topic/generic-abi/bX460iggiKg

Comparison with relocation_packer for aosp_marlin-userdebug:
$ du -B1 -s */out/target/product/marlin/system
 996958208      base/out/target/product/marlin/system
1008340992      no_pack/out/target/product/marlin/system
 997801984      sht_relr/out/target/product/marlin/system

base contains a build with current settings.
no_pack contains a build with relocation_packer disabled.
sht_relr contains a build with SHT_RELR sections enabled.

relocation_packer was saving 11,382,784 bytes (no_pack - base).
SHT_RELR sections are saving 10,539,008 bytes (no_pack - sht_relr).

Bug: None
Test: Built aosp_marlin-userdebug image, boots on device.
Test: Built aosp_x86_64-userdebug image, boots in emulator.
Change-Id: I448dc95baa4976b68ce2659b80498539426775f9
---
 cc/config/arm64_device.go  | 1 +
 cc/config/arm_device.go    | 1 +
 cc/config/x86_64_device.go | 1 +
 cc/relocation_packer.go    | 9 ++++++++-
 4 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/cc/config/arm64_device.go b/cc/config/arm64_device.go
index 5bb7749a8..146d00556 100644
--- a/cc/config/arm64_device.go
+++ b/cc/config/arm64_device.go
@@ -33,6 +33,7 @@ var (
 		"-Wl,--fix-cortex-a53-843419",
 		"-fuse-ld=gold",
 		"-Wl,--icf=safe",
+		"-Wl,--experimental-use-relr",
 	}
 
 	arm64Cppflags = []string{}
diff --git a/cc/config/arm_device.go b/cc/config/arm_device.go
index 66b3b3829..7e6d203d2 100644
--- a/cc/config/arm_device.go
+++ b/cc/config/arm_device.go
@@ -37,6 +37,7 @@ var (
 		"-Wl,--icf=safe",
 		"-Wl,--hash-style=gnu",
 		"-Wl,-m,armelf",
+		"-Wl,--experimental-use-relr",
 	}
 
 	armArmCflags = []string{
diff --git a/cc/config/x86_64_device.go b/cc/config/x86_64_device.go
index 12f3e6fa2..dea13fbad 100644
--- a/cc/config/x86_64_device.go
+++ b/cc/config/x86_64_device.go
@@ -30,6 +30,7 @@ var (
 
 	x86_64Ldflags = []string{
 		"-Wl,--hash-style=gnu",
+		"-Wl,--experimental-use-relr",
 	}
 
 	x86_64ArchVariantCflags = map[string][]string{
diff --git a/cc/relocation_packer.go b/cc/relocation_packer.go
index 500662365..824b538a8 100644
--- a/cc/relocation_packer.go
+++ b/cc/relocation_packer.go
@@ -45,7 +45,14 @@ type relocationPacker struct {
 }
 
 func (p *relocationPacker) packingInit(ctx BaseModuleContext) {
-	enabled := true
+	// Disable relocation_packer and migrate to SHT_RELR sections.
+	//
+	// Proposal for adding SHT_RELR sections in generic-abi is at
+	// https://groups.google.com/forum/#!topic/generic-abi/bX460iggiKg
+	//
+	// TODO: Remove relocation_packer and associated build logic.
+	enabled := false
+
 	// Relocation packer isn't available on Darwin yet
 	if runtime.GOOS == "darwin" {
 		enabled = false