Merge "Propagate LTO type from binary/DSO to object files"

am: 85ae70556e

Change-Id: I2d405590822345c73b8ad41732b8867081475147

cc/lto.go

@@ -40,10 +40,15 @@ type LTOProperties struct {
 	// Lto must violate capitialization style for acronyms so that it can be
 	// referred to in blueprint files as "lto"
 	Lto struct {
-		Full *bool `android:"arch_variant"`
+		Never *bool `android:"arch_variant"`
-		Thin *bool `android:"arch_variant"`
+		Full  *bool `android:"arch_variant"`
+		Thin  *bool `android:"arch_variant"`
 	} `android:"arch_variant"`
-	LTODep 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.
+	FullDep bool `blueprint:"mutated"`
+	ThinDep bool `blueprint:"mutated"`
 }
 
 type lto struct {
@@ -84,7 +89,7 @@ func (lto *lto) flags(ctx BaseModuleContext, flags Flags) Flags {
 
 // Can be called with a null receiver
 func (lto *lto) LTO() bool {
-	if lto == nil {
+	if lto == nil || lto.Disabled() {
 		return false
 	}
 
@@ -93,41 +98,91 @@ func (lto *lto) LTO() bool {
 	return full || thin
 }
 
+// Is lto.never explicitly set to true?
+func (lto *lto) Disabled() bool {
+	return lto.Properties.Lto.Never != nil && *lto.Properties.Lto.Never
+}
+
 // Propagate lto requirements down from binaries
 func ltoDepsMutator(mctx android.TopDownMutatorContext) {
-	if c, ok := mctx.Module().(*Module); ok && c.lto.LTO() {
+	if m, ok := mctx.Module().(*Module); ok && m.lto.LTO() {
-		full := Bool(c.lto.Properties.Lto.Full)
+		full := Bool(m.lto.Properties.Lto.Full)
-		thin := Bool(c.lto.Properties.Lto.Thin)
+		thin := Bool(m.lto.Properties.Lto.Thin)
 		if full && thin {
 			mctx.PropertyErrorf("LTO", "FullLTO and ThinLTO are mutually exclusive")
 		}
 
-		mctx.VisitDepsDepthFirst(func(m android.Module) {
+		mctx.WalkDeps(func(dep android.Module, parent android.Module) bool {
-			tag := mctx.OtherModuleDependencyTag(m)
+			tag := mctx.OtherModuleDependencyTag(dep)
 			switch tag {
 			case staticDepTag, staticExportDepTag, lateStaticDepTag, wholeStaticDepTag, objDepTag, reuseObjTag:
-				if cc, ok := m.(*Module); ok && cc.lto != nil {
+				if dep, ok := dep.(*Module); ok && dep.lto != nil &&
-					cc.lto.Properties.LTODep = true
+					!dep.lto.Disabled() {
+					if full && !Bool(dep.lto.Properties.Lto.Full) {
+						dep.lto.Properties.FullDep = true
+					}
+					if thin && !Bool(dep.lto.Properties.Lto.Thin) {
+						dep.lto.Properties.ThinDep = true
+					}
 				}
+
+				// Recursively walk static dependencies
+				return true
 			}
+
+			// Do not recurse down non-static dependencies
+			return false
 		})
 	}
 }
 
 // Create lto variants for modules that need them
 func ltoMutator(mctx android.BottomUpMutatorContext) {
-	if c, ok := mctx.Module().(*Module); ok && c.lto != nil {
+	if m, ok := mctx.Module().(*Module); ok && m.lto != nil {
-		if c.lto.LTO() {
+		// Create variations for LTO types required as static
-			mctx.SetDependencyVariation("lto")
+		// dependencies
-		} else if c.lto.Properties.LTODep {
+		variationNames := []string{""}
-			modules := mctx.CreateVariations("", "lto")
+		if m.lto.Properties.FullDep && !Bool(m.lto.Properties.Lto.Full) {
-			modules[0].(*Module).lto.Properties.Lto.Full = boolPtr(false)
+			variationNames = append(variationNames, "lto-full")
-			modules[0].(*Module).lto.Properties.Lto.Thin = boolPtr(false)
+		}
-			modules[0].(*Module).lto.Properties.LTODep = false
+		if m.lto.Properties.ThinDep && !Bool(m.lto.Properties.Lto.Thin) {
-			modules[1].(*Module).lto.Properties.LTODep = false
+			variationNames = append(variationNames, "lto-thin")
-			modules[1].(*Module).Properties.PreventInstall = true
+		}
-			modules[1].(*Module).Properties.HideFromMake = true
+
+		// Use correct dependencies if LTO property is explicitly set
+		// (mutually exclusive)
+		if Bool(m.lto.Properties.Lto.Full) {
+			mctx.SetDependencyVariation("lto-full")
+		}
+		if Bool(m.lto.Properties.Lto.Thin) {
+			mctx.SetDependencyVariation("lto-thin")
+		}
+
+		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-full" {
+					variation.lto.Properties.Lto.Full = boolPtr(true)
+					variation.lto.Properties.Lto.Thin = boolPtr(false)
+				}
+				if name == "lto-thin" {
+					variation.lto.Properties.Lto.Full = boolPtr(false)
+					variation.lto.Properties.Lto.Thin = boolPtr(true)
+				}
+				variation.Properties.PreventInstall = true
+				variation.Properties.HideFromMake = true
+				variation.lto.Properties.FullDep = false
+				variation.lto.Properties.ThinDep = false
+			}
 		}
-		c.lto.Properties.LTODep = false
 	}
 }