Convert LTO mutators to TransitionMutator
Convert ltoDepsMutator and ltoMutator to a TransitionMutator as a
step towards variants-on-demand.
Bug: 319288033
Test: lto_test.go
Change-Id: I2c9af73fd526adf58ff626831ababea466338205
diff --git a/cc/cc.go b/cc/cc.go
index 41fea47..31fa4fd 100644
--- a/cc/cc.go
+++ b/cc/cc.go
@@ -76,8 +76,7 @@
ctx.TopDown("orderfile_deps", orderfileDepsMutator)
ctx.BottomUp("orderfile", orderfileMutator).Parallel()
- ctx.TopDown("lto_deps", ltoDepsMutator)
- ctx.BottomUp("lto", ltoMutator).Parallel()
+ ctx.Transition("lto", <oTransitionMutator{})
ctx.BottomUp("check_linktype", checkLinkTypeMutator).Parallel()
ctx.TopDown("double_loadable", checkDoubleLoadableLibraries).Parallel()
diff --git a/cc/lto.go b/cc/lto.go
index 8b0880c..b2b4570 100644
--- a/cc/lto.go
+++ b/cc/lto.go
@@ -15,9 +15,12 @@
package cc
import (
- "android/soong/android"
+ "fmt"
+ "github.com/google/blueprint"
"github.com/google/blueprint/proptools"
+
+ "android/soong/android"
)
// LTO (link-time optimization) allows the compiler to optimize and generate
@@ -49,11 +52,6 @@
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.
- LtoDep bool `blueprint:"mutated"`
- NoLtoDep bool `blueprint:"mutated"`
-
// Use -fwhole-program-vtables cflag.
Whole_program_vtables *bool
}
@@ -176,86 +174,83 @@
return lto != nil && proptools.Bool(lto.Properties.Lto.Never)
}
-// Propagate lto requirements down from binaries
-func ltoDepsMutator(mctx android.TopDownMutatorContext) {
- if m, ok := mctx.Module().(*Module); ok {
- if m.lto == nil || m.lto.Properties.LtoEnabled == m.lto.Properties.LtoDefault {
- return
- }
-
- mctx.WalkDeps(func(dep android.Module, parent android.Module) bool {
- tag := mctx.OtherModuleDependencyTag(dep)
- libTag, isLibTag := tag.(libraryDependencyTag)
-
- // Do not recurse down non-static dependencies
- if isLibTag {
- if !libTag.static() {
- return false
- }
- } else {
- if tag != objDepTag && tag != reuseObjTag {
- return false
- }
- }
-
- if dep, ok := dep.(*Module); ok {
- if m.lto.Properties.LtoEnabled {
- dep.lto.Properties.LtoDep = true
- } else {
- dep.lto.Properties.NoLtoDep = true
- }
- }
-
- // Recursively walk static dependencies
- return true
- })
+func ltoPropagateViaDepTag(tag blueprint.DependencyTag) bool {
+ libTag, isLibTag := tag.(libraryDependencyTag)
+ // Do not recurse down non-static dependencies
+ if isLibTag {
+ return libTag.static()
+ } else {
+ return tag == objDepTag || tag == reuseObjTag || tag == staticVariantTag
}
}
-// Create lto variants for modules that need them
-func ltoMutator(mctx android.BottomUpMutatorContext) {
- if m, ok := mctx.Module().(*Module); ok && m.lto != nil {
- // Create variations for LTO types required as static
- // dependencies
- variationNames := []string{""}
- if m.lto.Properties.LtoDep {
- variationNames = append(variationNames, "lto-thin")
- }
- if m.lto.Properties.NoLtoDep {
- variationNames = append(variationNames, "lto-none")
+// ltoTransitionMutator creates LTO variants of cc modules. Variant "" is the default variant, which may
+// or may not have LTO enabled depending on the config and the module's type and properties. "lto-thin" or
+// "lto-none" variants are created when a module needs to compile in the non-default state for that module.
+type ltoTransitionMutator struct{}
+
+const LTO_NONE_VARIATION = "lto-none"
+const LTO_THIN_VARIATION = "lto-thin"
+
+func (l *ltoTransitionMutator) Split(ctx android.BaseModuleContext) []string {
+ return []string{""}
+}
+
+func (l *ltoTransitionMutator) OutgoingTransition(ctx android.OutgoingTransitionContext, sourceVariation string) string {
+ if m, ok := ctx.Module().(*Module); ok && m.lto != nil {
+ if !ltoPropagateViaDepTag(ctx.DepTag()) {
+ return ""
}
- if !m.lto.Properties.LtoEnabled {
- mctx.SetDependencyVariation("lto-none")
+ if sourceVariation != "" {
+ return sourceVariation
}
+
+ // Always request an explicit variation, IncomingTransition will rewrite it back to the default variation
+ // if necessary.
if m.lto.Properties.LtoEnabled {
- mctx.SetDependencyVariation("lto-thin")
+ return LTO_THIN_VARIATION
+ } else {
+ return LTO_NONE_VARIATION
}
+ }
+ return ""
+}
- if len(variationNames) > 1 {
- modules := mctx.CreateVariations(variationNames...)
- for i, name := range variationNames {
- variation := modules[i].(*Module)
- // Default module which will be
- // installed. Variation set above according to
- // explicit LTO properties
- if name == "" {
- continue
- }
-
- // LTO properties for dependencies
- if name == "lto-thin" {
- variation.lto.Properties.LtoEnabled = true
- }
- if name == "lto-none" {
- variation.lto.Properties.LtoEnabled = false
- }
- 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
- }
+func (l *ltoTransitionMutator) IncomingTransition(ctx android.IncomingTransitionContext, incomingVariation string) string {
+ if m, ok := ctx.Module().(*Module); ok && m.lto != nil {
+ if m.lto.Never() {
+ return ""
}
+ // Rewrite explicit variations back to the default variation if the default variation matches.
+ if incomingVariation == LTO_THIN_VARIATION && m.lto.Properties.LtoDefault {
+ return ""
+ } else if incomingVariation == LTO_NONE_VARIATION && !m.lto.Properties.LtoDefault {
+ return ""
+ }
+ return incomingVariation
+ }
+ return ""
+}
+
+func (l *ltoTransitionMutator) Mutate(ctx android.BottomUpMutatorContext, variation string) {
+ // Default module which will be installed. Variation set above according to explicit LTO properties.
+ if variation == "" {
+ return
+ }
+
+ if m, ok := ctx.Module().(*Module); ok && m.lto != nil {
+ // Non-default variation, set the LTO properties to match the variation.
+ switch variation {
+ case LTO_THIN_VARIATION:
+ m.lto.Properties.LtoEnabled = true
+ case LTO_NONE_VARIATION:
+ m.lto.Properties.LtoEnabled = false
+ default:
+ panic(fmt.Errorf("unknown variation %s", variation))
+ }
+ // Non-default variations are never installed.
+ m.Properties.PreventInstall = true
+ m.Properties.HideFromMake = true
}
}
diff --git a/cc/lto_test.go b/cc/lto_test.go
index 7b7fe8c..e4b5a3a 100644
--- a/cc/lto_test.go
+++ b/cc/lto_test.go
@@ -146,8 +146,9 @@
t.Errorf("'root' missing dependency on the default variant of 'foo'")
}
- if !hasDep(result, libRootLtoNever, libFoo.Module()) {
- t.Errorf("'root_no_lto' missing dependency on the default variant of 'foo'")
+ libFooNoLto := result.ModuleForTests("foo", "android_arm64_armv8-a_static_lto-none")
+ if !hasDep(result, libRootLtoNever, libFooNoLto.Module()) {
+ t.Errorf("'root_no_lto' missing dependency on the lto_none variant of 'foo'")
}
libFooCFlags := libFoo.Rule("cc").Args["cFlags"]