diff --git a/android/config.go b/android/config.go
index c9d7dab..a81b928 100644
--- a/android/config.go
+++ b/android/config.go
@@ -570,8 +570,8 @@
 	return String(c.productVariables.BuildId)
 }
 
-func (c *config) BuildNumberFromFile() string {
-	return String(c.productVariables.BuildNumberFromFile)
+func (c *config) BuildNumberFile(ctx PathContext) Path {
+	return PathForOutput(ctx, String(c.productVariables.BuildNumberFile))
 }
 
 // DeviceName returns the name of the current device target
diff --git a/android/variable.go b/android/variable.go
index 06bd4ed..e4dd9fc 100644
--- a/android/variable.go
+++ b/android/variable.go
@@ -140,9 +140,8 @@
 	// Suffix to add to generated Makefiles
 	Make_suffix *string `json:",omitempty"`
 
-	BuildId             *string `json:",omitempty"`
-	BuildNumberFromFile *string `json:",omitempty"`
-	DateFromFile        *string `json:",omitempty"`
+	BuildId         *string `json:",omitempty"`
+	BuildNumberFile *string `json:",omitempty"`
 
 	Platform_version_name                     *string  `json:",omitempty"`
 	Platform_sdk_version                      *int     `json:",omitempty"`
@@ -347,7 +346,7 @@
 
 func (v *productVariables) SetDefaultConfig() {
 	*v = productVariables{
-		BuildNumberFromFile: stringPtr("123456789"),
+		BuildNumberFile: stringPtr("build_number.txt"),
 
 		Platform_version_name:             stringPtr("Q"),
 		Platform_sdk_version:              intPtr(28),
diff --git a/cc/linker.go b/cc/linker.go
index af4cbf3..a7b621a 100644
--- a/cc/linker.go
+++ b/cc/linker.go
@@ -501,19 +501,21 @@
 var injectVersionSymbol = pctx.AndroidStaticRule("injectVersionSymbol",
 	blueprint.RuleParams{
 		Command: "$symbolInjectCmd -i $in -o $out -s soong_build_number " +
-			"-from 'SOONG BUILD NUMBER PLACEHOLDER' -v $buildNumberFromFile",
+			"-from 'SOONG BUILD NUMBER PLACEHOLDER' -v $$(cat $buildNumberFile)",
 		CommandDeps: []string{"$symbolInjectCmd"},
 	},
-	"buildNumberFromFile")
+	"buildNumberFile")
 
 func (linker *baseLinker) injectVersionSymbol(ctx ModuleContext, in android.Path, out android.WritablePath) {
+	buildNumberFile := ctx.Config().BuildNumberFile(ctx)
 	ctx.Build(pctx, android.BuildParams{
 		Rule:        injectVersionSymbol,
 		Description: "inject version symbol",
 		Input:       in,
 		Output:      out,
+		OrderOnly:   android.Paths{buildNumberFile},
 		Args: map[string]string{
-			"buildNumberFromFile": proptools.NinjaEscape(ctx.Config().BuildNumberFromFile()),
+			"buildNumberFile": buildNumberFile.String(),
 		},
 	})
 }
diff --git a/java/droiddoc.go b/java/droiddoc.go
index 70d997a..1ac7444 100644
--- a/java/droiddoc.go
+++ b/java/droiddoc.go
@@ -773,6 +773,7 @@
 }
 
 func (d *Droiddoc) doclavaDocsFlags(ctx android.ModuleContext, cmd *android.RuleBuilderCommand, docletPath classpath) {
+	buildNumberFile := ctx.Config().BuildNumberFile(ctx)
 	// Droiddoc always gets "-source 1.8" because it doesn't support 1.9 sources.  For modules with 1.9
 	// sources, droiddoc will get sources produced by metalava which will have already stripped out the
 	// 1.9 language features.
@@ -782,7 +783,7 @@
 		Flag("-XDignore.symbol.file").
 		FlagWithArg("-doclet ", "com.google.doclava.Doclava").
 		FlagWithInputList("-docletpath ", docletPath.Paths(), ":").
-		FlagWithArg("-hdf page.build ", ctx.Config().BuildId()+"-"+ctx.Config().BuildNumberFromFile()).
+		FlagWithArg("-hdf page.build ", ctx.Config().BuildId()+"-$(cat "+buildNumberFile.String()+")").OrderOnly(buildNumberFile).
 		FlagWithArg("-hdf page.now ", `"$(date -d @$(cat `+ctx.Config().Getenv("BUILD_DATETIME_FILE")+`) "+%d %b %Y %k:%M")" `)
 
 	if String(d.properties.Custom_template) == "" {