Merge "Turn on Global ThinLTO by default" into main
diff --git a/cc/cc_test.go b/cc/cc_test.go
index 7534db2..fe54463 100644
--- a/cc/cc_test.go
+++ b/cc/cc_test.go
@@ -4979,6 +4979,7 @@
conly := []string{"-fPIC", "${config.CommonGlobalConlyflags}"}
cppOnly := []string{"-fPIC", "${config.CommonGlobalCppflags}", "${config.DeviceGlobalCppflags}", "${config.ArmCppflags}"}
+ ltoFlags := []string{"-flto=thin", "-fsplit-lto-unit"}
cflags := []string{"-Werror", "-std=candcpp"}
cstd := []string{"-std=gnu17", "-std=conly"}
@@ -5005,17 +5006,17 @@
{
name: "c",
src: "foo.c",
- expected: combineSlices(baseExpectedFlags, conly, expectedIncludes, cflags, cstd, lastIncludes, []string{"${config.NoOverrideGlobalCflags}", "${config.NoOverrideExternalGlobalCflags}"}),
+ expected: combineSlices(baseExpectedFlags, conly, expectedIncludes, cflags, ltoFlags, cstd, lastIncludes, []string{"${config.NoOverrideGlobalCflags}", "${config.NoOverrideExternalGlobalCflags}"}),
},
{
name: "cc",
src: "foo.cc",
- expected: combineSlices(baseExpectedFlags, cppOnly, expectedIncludes, cflags, cppstd, lastIncludes, []string{"${config.NoOverrideGlobalCflags}", "${config.NoOverrideExternalGlobalCflags}"}),
+ expected: combineSlices(baseExpectedFlags, cppOnly, expectedIncludes, cflags, ltoFlags, cppstd, lastIncludes, []string{"${config.NoOverrideGlobalCflags}", "${config.NoOverrideExternalGlobalCflags}"}),
},
{
name: "assemble",
src: "foo.s",
- expected: combineSlices(baseExpectedFlags, []string{"${config.CommonGlobalAsflags}"}, expectedIncludes, lastIncludes),
+ expected: combineSlices(baseExpectedFlags, []string{"${config.CommonGlobalAsflags}"}, expectedIncludes, ltoFlags, lastIncludes),
},
}
diff --git a/cc/lto.go b/cc/lto.go
index 510dd79..ff2bf5a 100644
--- a/cc/lto.go
+++ b/cc/lto.go
@@ -47,6 +47,7 @@
} `android:"arch_variant"`
LtoEnabled bool `blueprint:"mutated"`
+ LtoDefault bool `blueprint:"mutated"`
// Dep properties indicate that this module needs to be built with LTO
// since it is an object dependency of an LTO module.
@@ -66,7 +67,34 @@
}
func (lto *lto) begin(ctx BaseModuleContext) {
- lto.Properties.LtoEnabled = lto.LTO(ctx)
+ // First, determine the module indepedent default LTO mode.
+ ltoDefault := GlobalThinLTO(ctx)
+ if ctx.Config().IsEnvTrue("DISABLE_LTO") {
+ ltoDefault = false
+ } else if ctx.Host() {
+ // Performance and binary size are less important for host binaries.
+ ltoDefault = false
+ }
+
+ // Then, determine the actual LTO mode to use. If different from `ltoDefault`, a variant needs
+ // to be created.
+ ltoEnabled := ltoDefault
+ if lto.Never() {
+ ltoEnabled = false
+ } else if lto.ThinLTO() {
+ // Module explicitly requests for LTO.
+ ltoEnabled = true
+ } else if ctx.testBinary() || ctx.testLibrary() {
+ // Do not enable LTO for tests for better debugging.
+ ltoEnabled = false
+ } else if ctx.isVndk() {
+ // FIXME: ThinLTO for VNDK produces different output.
+ // b/169217596
+ ltoEnabled = false
+ }
+
+ lto.Properties.LtoDefault = ltoDefault
+ lto.Properties.LtoEnabled = ltoEnabled
}
func (lto *lto) flags(ctx BaseModuleContext, flags Flags) Flags {
@@ -118,34 +146,6 @@
return flags
}
-// Determine which LTO mode to use for the given module.
-func (lto *lto) LTO(ctx BaseModuleContext) bool {
- if lto.Never() {
- return false
- }
- if ctx.Config().IsEnvTrue("DISABLE_LTO") {
- return false
- }
- // Module explicitly requests for LTO.
- if lto.ThinLTO() {
- return true
- }
- // LP32 has many subtle issues and less test coverage.
- if ctx.Arch().ArchType.Multilib == "lib32" {
- return false
- }
- // Performance and binary size are less important for host binaries and tests.
- if ctx.Host() || ctx.testBinary() || ctx.testLibrary() {
- return false
- }
- // FIXME: ThinLTO for VNDK produces different output.
- // b/169217596
- if ctx.isVndk() {
- return false
- }
- return GlobalThinLTO(ctx)
-}
-
func (lto *lto) ThinLTO() bool {
return lto != nil && proptools.Bool(lto.Properties.Lto.Thin)
}
@@ -155,15 +155,13 @@
}
func GlobalThinLTO(ctx android.BaseModuleContext) bool {
- return ctx.Config().IsEnvTrue("GLOBAL_THINLTO")
+ return !ctx.Config().IsEnvFalse("GLOBAL_THINLTO")
}
// Propagate lto requirements down from binaries
func ltoDepsMutator(mctx android.TopDownMutatorContext) {
- defaultLTOMode := GlobalThinLTO(mctx)
-
if m, ok := mctx.Module().(*Module); ok {
- if m.lto == nil || m.lto.Properties.LtoEnabled == defaultLTOMode {
+ if m.lto == nil || m.lto.Properties.LtoEnabled == m.lto.Properties.LtoDefault {
return
}
@@ -238,6 +236,7 @@
}
variation.Properties.PreventInstall = true
variation.Properties.HideFromMake = true
+ variation.lto.Properties.LtoDefault = m.lto.Properties.LtoDefault
variation.lto.Properties.LtoDep = false
variation.lto.Properties.NoLtoDep = false
}