add crate_root property to rust modules

The crate_root property will be used to specify the entry point for a
rustc compilation. This will allow the srcs property to be used to
collect all src inputs to rustc rather than just the entry point.

Bug: 286077158
Test: m libnum_traits
Change-Id: I1a167182305dcc11cc927d562ceed622153111d3

1 files changed, 10 insertions, 8 deletions

diff --git a/rust/library.go b/rust/library.go
index 3f031c10c..7432a12be 100644
--- a/rust/library.go
+++ b/rust/library.go
@@ -489,7 +489,7 @@ func (library *libraryDecorator) compile(ctx ModuleContext, flags Flags, deps Pa
 	var outputFile android.ModuleOutPath
 	var ret buildOutput
 	var fileName string
-	srcPath := library.srcPath(ctx, deps)
+	crateRootPath := library.crateRootPath(ctx, deps)
 
 	if library.sourceProvider != nil {
 		deps.srcProviderFiles = append(deps.srcProviderFiles, library.sourceProvider.Srcs()...)
@@ -536,13 +536,13 @@ func (library *libraryDecorator) compile(ctx ModuleContext, flags Flags, deps Pa
 
 	// Call the appropriate builder for this library type
 	if library.rlib() {
-		ret.kytheFile = TransformSrctoRlib(ctx, srcPath, deps, flags, outputFile).kytheFile
+		ret.kytheFile = TransformSrctoRlib(ctx, crateRootPath, deps, flags, outputFile).kytheFile
 	} else if library.dylib() {
-		ret.kytheFile = TransformSrctoDylib(ctx, srcPath, deps, flags, outputFile).kytheFile
+		ret.kytheFile = TransformSrctoDylib(ctx, crateRootPath, deps, flags, outputFile).kytheFile
 	} else if library.static() {
-		ret.kytheFile = TransformSrctoStatic(ctx, srcPath, deps, flags, outputFile).kytheFile
+		ret.kytheFile = TransformSrctoStatic(ctx, crateRootPath, deps, flags, outputFile).kytheFile
 	} else if library.shared() {
-		ret.kytheFile = TransformSrctoShared(ctx, srcPath, deps, flags, outputFile).kytheFile
+		ret.kytheFile = TransformSrctoShared(ctx, crateRootPath, deps, flags, outputFile).kytheFile
 	}
 
 	if library.rlib() || library.dylib() {
@@ -585,13 +585,15 @@ func (library *libraryDecorator) compile(ctx ModuleContext, flags Flags, deps Pa
 	return ret
 }
 
-func (library *libraryDecorator) srcPath(ctx ModuleContext, _ PathDeps) android.Path {
+func (library *libraryDecorator) crateRootPath(ctx ModuleContext, _ PathDeps) android.Path {
 	if library.sourceProvider != nil {
 		// Assume the first source from the source provider is the library entry point.
 		return library.sourceProvider.Srcs()[0]
-	} else {
+	} else if library.baseCompiler.Properties.Crate_root == nil {
 		path, _ := srcPathFromModuleSrcs(ctx, library.baseCompiler.Properties.Srcs)
 		return path
+	} else {
+		return android.PathForModuleSrc(ctx, *library.baseCompiler.Properties.Crate_root)
 	}
 }
 
@@ -606,7 +608,7 @@ func (library *libraryDecorator) rustdoc(ctx ModuleContext, flags Flags,
 		return android.OptionalPath{}
 	}
 
-	return android.OptionalPathForPath(Rustdoc(ctx, library.srcPath(ctx, deps),
+	return android.OptionalPathForPath(Rustdoc(ctx, library.crateRootPath(ctx, deps),
 		deps, flags))
 }