From c702ebd886fde17cea33a9f2af8b5881bd68f1d0 Mon Sep 17 00:00:00 2001
From: Yi Kong <yikong@google.com>
Date: Fri, 19 Aug 2022 16:02:45 +0800
Subject: [PATCH] Do not enable ThinLTO for CFI enabled projects

CFI projects already use full LTO.

Test: GLOBAL_THINLTO=true m
Change-Id: I8a57efc237aed977f57dd4040500cc5f84843c3d
---
 cc/cc.go  | 12 ++++++++++++
 cc/lto.go | 10 ++++++++--
 2 files changed, 20 insertions(+), 2 deletions(-)

diff --git a/cc/cc.go b/cc/cc.go
index c71fb347c..336771a83 100644
--- a/cc/cc.go
+++ b/cc/cc.go
@@ -514,6 +514,7 @@ type ModuleContextIntf interface {
 	getVndkExtendsModuleName() string
 	isAfdoCompile() bool
 	isPgoCompile() bool
+	isCfi() bool
 	isNDKStubLibrary() bool
 	useClangLld(actx ModuleContext) bool
 	isForPlatform() bool
@@ -1314,6 +1315,13 @@ func (c *Module) isPgoCompile() bool {
 	return false
 }
 
+func (c *Module) isCfi() bool {
+	if sanitize := c.sanitize; sanitize != nil {
+		return Bool(sanitize.Properties.Sanitize.Cfi)
+	}
+	return false
+}
+
 func (c *Module) isNDKStubLibrary() bool {
 	if _, ok := c.compiler.(*stubDecorator); ok {
 		return true
@@ -1592,6 +1600,10 @@ func (ctx *moduleContextImpl) isPgoCompile() bool {
 	return ctx.mod.isPgoCompile()
 }
 
+func (ctx *moduleContextImpl) isCfi() bool {
+	return ctx.mod.isCfi()
+}
+
 func (ctx *moduleContextImpl) isNDKStubLibrary() bool {
 	return ctx.mod.isNDKStubLibrary()
 }
diff --git a/cc/lto.go b/cc/lto.go
index 1da69bf16..455ff7edc 100644
--- a/cc/lto.go
+++ b/cc/lto.go
@@ -136,10 +136,16 @@ func (lto *lto) LTO(ctx BaseModuleContext) bool {
 }
 
 func (lto *lto) DefaultThinLTO(ctx BaseModuleContext) bool {
+	// LP32 has many subtle issues and less test coverage.
 	lib32 := ctx.Arch().ArchType.Multilib == "lib32"
+	// CFI enables full LTO.
+	cfi := ctx.isCfi()
+	// Performance and binary size are less important for host binaries.
 	host := ctx.Host()
-	vndk := ctx.isVndk() // b/169217596
-	return GlobalThinLTO(ctx) && !lto.Never() && !lib32 && !host && !vndk
+	// FIXME: ThinLTO for VNDK produces different output.
+	// b/169217596
+	vndk := ctx.isVndk()
+	return GlobalThinLTO(ctx) && !lto.Never() && !lib32 && !cfi && !host && !vndk
 }
 
 func (lto *lto) FullLTO() bool {