[rust] Add SourceProviders as crates support.

This allows SourceProvider modules to create rust_library variants so
that generated source can be referenced as an external crate rather than
via an include macro. This is done by including rust_bindgen modules
like any other library, as a dependency in either rlibs, dylibs, or
rustlibs.

This renames the stem and flags properties for rust_bindgen modules to
source_stem and bindgen_flags, respectively. This deconflicts with the
usage in baseCompiler.

This also removes 'subName' from the Module struct and moves it over to
SourceProvider, which was the only user. This allows us to set it in
baseSourceProvider's AndroidMk; setting it in Module's AndroidMk was
causing problems finding NOTICE files for bindgen library variants.

Bug: 159064919
Test: New Soong tests pass.
Test: Local test rust_binary can use rust_bindgen module as a crate.

Change-Id: Ieb2cb614c2dd0b5aa7120541d77f6f822a6a1806

1 files changed, 12 insertions, 1 deletions

diff --git a/rust/compiler.go b/rust/compiler.go
index 040219dc4..ec059c37c 100644
--- a/rust/compiler.go
+++ b/rust/compiler.go
@@ -81,7 +81,10 @@ type BaseCompilerProperties struct {
 	// list of C static library dependencies
 	Static_libs []string `android:"arch_variant"`
 
-	// crate name, required for libraries. This must be the expected extern crate name used in source
+	// crate name, required for modules which produce Rust libraries: rust_library, rust_ffi and SourceProvider
+	// modules which create library variants (rust_bindgen). This must be the expected extern crate name used in
+	// source, and is required to conform to an enforced format matching library output files (if the output file is
+	// lib<someName><suffix>, the crate_name property must be <someName>).
 	Crate_name string `android:"arch_variant"`
 
 	// list of features to enable for this crate
@@ -120,6 +123,14 @@ type baseCompiler struct {
 	distFile              android.OptionalPath
 }
 
+func (compiler *baseCompiler) Disabled() bool {
+	return false
+}
+
+func (compiler *baseCompiler) SetDisabled() {
+	panic("baseCompiler does not implement SetDisabled()")
+}
+
 func (compiler *baseCompiler) coverageOutputZipPath() android.OptionalPath {
 	panic("baseCompiler does not implement coverageOutputZipPath()")
 }