Hide CFI behind a global flag.

This CL ensures that locally enabling CFI in a .bp file is not honored
unless it is enabled globally using ENABLE_CFI=true first, effectively
hiding it behind a flag.

Bug: 30227045
Bug: 22033465
Test: m -j40 works and device boots
Test: cfi is correctly honored only when the global flag is set.
Change-Id: Iccc6e4bf5e7828ab8ce6056f3e40922712faa0d8

android/config.go

@@ -398,6 +398,10 @@ func (c *config) SanitizeDeviceArch() []string {
 	return append([]string(nil), c.ProductVariables.SanitizeDeviceArch...)
 }
 
+func (c *config) EnableCFI() bool {
+	return Bool(c.ProductVariables.EnableCFI)
+}
+
 func (c *config) Android64() bool {
 	for _, t := range c.Targets[Device] {
 		if t.Arch.ArchType.Multilib == "lib64" {

android/variable.go

@@ -124,6 +124,7 @@ type productVariables struct {
 	UseGoma                    *bool `json:",omitempty"`
 	Debuggable                 *bool `json:",omitempty"`
 	Eng                        *bool `json:",omitempty"`
+	EnableCFI                  *bool `json:",omitempty"`
 
 	VendorPath *string `json:",omitempty"`
 

cc/sanitize.go

@@ -161,6 +161,11 @@ func (sanitize *sanitize) begin(ctx BaseModuleContext) {
 		}
 	}
 
+	if !ctx.AConfig().EnableCFI() {
+		s.Cfi = nil
+		s.Diag.Cfi = nil
+	}
+
 	if ctx.staticBinary() {
 		s.Address = nil
 		s.Coverage = nil