Refactor dexpreopt for boot jars to allow more complex dependencies.

After this change, the dependency hierachy can be arbitrarily deep. For
example, you can have one boot image that extends another boot image
that extends yet another boot image.

Bug: 269230245
Test: m
Change-Id: I096d0b57bda36b982ecc97378647f9c59071a3bf

1 files changed, 30 insertions, 9 deletions

diff --git a/java/dexpreopt_config.go b/java/dexpreopt_config.go
index 2975130f3..76c78cb29 100644
--- a/java/dexpreopt_config.go
+++ b/java/dexpreopt_config.go
@@ -94,10 +94,7 @@ func genBootImageConfigs(ctx android.PathContext) map[string]*bootImageConfig {
 		deviceDir := android.PathForOutput(ctx, ctx.Config().DeviceName())
 
 		configs := genBootImageConfigRaw(ctx)
-		artCfg := configs[artBootImageName]
-		frameworkCfg := configs[frameworkBootImageName]
 
-		// common to all configs
 		for _, c := range configs {
 			c.dir = deviceDir.Join(ctx, "dex_"+c.name+"jars")
 			c.symbolsDir = deviceDir.Join(ctx, "dex_"+c.name+"jars_unstripped")
@@ -133,18 +130,42 @@ func genBootImageConfigs(ctx android.PathContext) map[string]*bootImageConfig {
 			c.zip = c.dir.Join(ctx, c.name+".zip")
 		}
 
-		// specific to the framework config
-		frameworkCfg.dexPathsDeps = append(artCfg.dexPathsDeps, frameworkCfg.dexPathsDeps...)
-		for i := range targets {
-			frameworkCfg.variants[i].primaryImages = artCfg.variants[i].imagePathOnHost
-			frameworkCfg.variants[i].primaryImagesDeps = artCfg.variants[i].imagesDeps.Paths()
-			frameworkCfg.variants[i].dexLocationsDeps = append(artCfg.variants[i].dexLocations, frameworkCfg.variants[i].dexLocationsDeps...)
+		visited := make(map[string]bool)
+		for _, c := range configs {
+			calculateDepsRecursive(c, targets, visited)
 		}
 
 		return configs
 	}).(map[string]*bootImageConfig)
 }
 
+// calculateDepsRecursive calculates the dependencies of the given boot image config and all its
+// ancestors, if they are not visited.
+// The boot images are supposed to form a tree, where the root is the primary boot image. We do not
+// expect loops (e.g., A extends B, B extends C, C extends A), and we let them crash soong with a
+// stack overflow.
+// Note that a boot image config only has a pointer to the parent, not to children. Therefore, we
+// first go up through the parent chain, and then go back down to visit every code along the path.
+// `visited` is a map where a key is a boot image name and the value indicates whether the boot
+// image config is visited. The boot image names are guaranteed to be unique because they come from
+// `genBootImageConfigRaw` above, which also returns a map and would fail in the first place if the
+// names were not unique.
+func calculateDepsRecursive(c *bootImageConfig, targets []android.Target, visited map[string]bool) {
+	if c.extends == nil || visited[c.name] {
+		return
+	}
+	if c.extends.extends != nil {
+		calculateDepsRecursive(c.extends, targets, visited)
+	}
+	visited[c.name] = true
+	c.dexPathsDeps = android.Concat(c.extends.dexPathsDeps, c.dexPathsDeps)
+	for i := range targets {
+		c.variants[i].baseImages = android.Concat(c.extends.variants[i].baseImages, android.OutputPaths{c.extends.variants[i].imagePathOnHost})
+		c.variants[i].baseImagesDeps = android.Concat(c.extends.variants[i].baseImagesDeps, c.extends.variants[i].imagesDeps.Paths())
+		c.variants[i].dexLocationsDeps = android.Concat(c.extends.variants[i].dexLocationsDeps, c.variants[i].dexLocationsDeps)
+	}
+}
+
 func artBootImageConfig(ctx android.PathContext) *bootImageConfig {
 	return genBootImageConfigs(ctx)[artBootImageName]
 }