Enforce correct rust library file names.

rustc expects libraries and proc_macro filenames to conform to
a particular format, alphanumeric with underscores and lib${crate_name}.*.
Enforce this with a check when getStem() is called.

This makes the crate_name property required for proc_macros and
libraries. This also removes the notion of a default crate name derived
from the module name. It's not needed for binaries, so this won't impact
them.

Bug: 143579265
Test: m -j crosvm.experimental
Change-Id: I2770cf7d02dd4291c3d240d58d242b940098dcee

rust/builder.go

@@ -88,7 +88,9 @@ func transformSrctoCrate(ctx android.ModuleContext, main android.Path,
 	rustcFlags = append(rustcFlags, flags.GlobalRustFlags...)
 	rustcFlags = append(rustcFlags, flags.RustFlags...)
 	rustcFlags = append(rustcFlags, "--crate-type="+crate_type)
+	if crate_name != "" {
 		rustcFlags = append(rustcFlags, "--crate-name="+crate_name)
+	}
 	if targetTriple != "" {
 		rustcFlags = append(rustcFlags, "--target="+targetTriple)
 		linkFlags = append(linkFlags, "-target "+targetTriple)

rust/compiler.go

@@ -18,9 +18,10 @@ import (
 	"fmt"
 	"path/filepath"
 
+	"github.com/google/blueprint/proptools"
+
 	"android/soong/android"
 	"android/soong/rust/config"
-	"github.com/google/blueprint/proptools"
 )
 
 func getEdition(compiler *baseCompiler) string {
@@ -64,7 +65,7 @@ type BaseCompilerProperties struct {
 	// list of C static library dependencies
 	Static_libs []string `android:"arch_variant"`
 
-	// crate name (defaults to module name); if library, this must be the expected extern crate name
+	// crate name, required for libraries. This must be the expected extern crate name used in source
 	Crate_name string `android:"arch_variant"`
 
 	// list of features to enable for this crate
@@ -207,6 +208,7 @@ func (compiler *baseCompiler) getStemWithoutSuffix(ctx BaseModuleContext) string
 
 	return stem
 }
+
 func (compiler *baseCompiler) relativeInstallPath() string {
 	return String(compiler.Properties.Relative_install_path)
 }

rust/library.go

@@ -15,6 +15,9 @@
 package rust
 
 import (
+	"regexp"
+	"strings"
+
 	"android/soong/android"
 )
 
@@ -354,6 +357,33 @@ func (library *libraryDecorator) compile(ctx ModuleContext, flags Flags, deps Pa
 	return outputFile
 }
 
+func (library *libraryDecorator) getStem(ctx ModuleContext) string {
+	stem := library.baseCompiler.getStemWithoutSuffix(ctx)
+	validateLibraryStem(ctx, stem, library.crateName())
+
+	return stem + String(library.baseCompiler.Properties.Suffix)
+}
+
+var validCrateName = regexp.MustCompile("[^a-zA-Z0-9_]+")
+
+func validateLibraryStem(ctx BaseModuleContext, filename string, crate_name string) {
+	if crate_name == "" {
+		ctx.PropertyErrorf("crate_name", "crate_name must be defined.")
+	}
+
+	// crate_names are used for the library output file, and rustc expects these
+	// to be alphanumeric with underscores allowed.
+	if validCrateName.MatchString(crate_name) {
+		ctx.PropertyErrorf("crate_name",
+			"library crate_names must be alphanumeric with underscores allowed")
+	}
+
+	// Libraries are expected to begin with "lib" followed by the crate_name
+	if !strings.HasPrefix(filename, "lib"+crate_name) {
+		ctx.ModuleErrorf("Invalid name or stem property; library filenames must start with lib<crate_name>")
+	}
+}
+
 func LibraryMutator(mctx android.BottomUpMutatorContext) {
 	if m, ok := mctx.Module().(*Module); ok && m.compiler != nil {
 		switch library := m.compiler.(type) {

rust/library_test.go

@@ -77,3 +77,40 @@ func TestDylibPreferDynamic(t *testing.T) {
 		t.Errorf("missing prefer-dynamic flag for libfoo dylib, rustcFlags: %#v", libfooDylib.Args["rustcFlags"])
 	}
 }
+
+func TestValidateLibraryStem(t *testing.T) {
+	testRustError(t, "crate_name must be defined.", `
+			rust_library_host {
+				name: "libfoo",
+				srcs: ["foo.rs"],
+			}`)
+
+	testRustError(t, "library crate_names must be alphanumeric with underscores allowed", `
+			rust_library_host {
+				name: "libfoo-bar",
+				srcs: ["foo.rs"],
+				crate_name: "foo-bar"
+			}`)
+
+	testRustError(t, "Invalid name or stem property; library filenames must start with lib<crate_name>", `
+			rust_library_host {
+				name: "foobar",
+				srcs: ["foo.rs"],
+				crate_name: "foo_bar"
+			}`)
+	testRustError(t, "Invalid name or stem property; library filenames must start with lib<crate_name>", `
+			rust_library_host {
+				name: "foobar",
+				stem: "libfoo",
+				srcs: ["foo.rs"],
+				crate_name: "foo_bar"
+			}`)
+	testRustError(t, "Invalid name or stem property; library filenames must start with lib<crate_name>", `
+			rust_library_host {
+				name: "foobar",
+				stem: "foo_bar",
+				srcs: ["foo.rs"],
+				crate_name: "foo_bar"
+			}`)
+
+}

rust/proc_macro.go

@@ -77,3 +77,10 @@ func (procMacro *procMacroDecorator) compile(ctx ModuleContext, flags Flags, dep
 	TransformSrctoProcMacro(ctx, srcPath, deps, flags, outputFile, deps.linkDirs)
 	return outputFile
 }
+
+func (procMacro *procMacroDecorator) getStem(ctx ModuleContext) string {
+	stem := procMacro.baseCompiler.getStemWithoutSuffix(ctx)
+	validateLibraryStem(ctx, stem, procMacro.crateName())
+
+	return stem + String(procMacro.baseCompiler.Properties.Suffix)
+}

rust/rust.go

@@ -225,12 +225,8 @@ func DefaultsFactory(props ...interface{}) android.Module {
 }
 
 func (mod *Module) CrateName() string {
-	if mod.compiler != nil && mod.compiler.crateName() != "" {
 	return mod.compiler.crateName()
 }
-	// Default crate names replace '-' in the name to '_'
-	return strings.Replace(mod.BaseModuleName(), "-", "_", -1)
-}
 
 func (mod *Module) CcLibrary() bool {
 	if mod.compiler != nil {

rust/rust_test.go

@@ -129,44 +129,33 @@ func TestLinkPathFromFilePath(t *testing.T) {
 	}
 }
 
-// Test default crate names from module names are generated correctly.
-func TestDefaultCrateName(t *testing.T) {
-	ctx := testRust(t, `
-		rust_library_host_dylib {
-			name: "fizz-buzz",
-			srcs: ["foo.rs"],
-		}`)
-	module := ctx.ModuleForTests("fizz-buzz", "linux_glibc_x86_64_dylib").Module().(*Module)
-	crateName := module.CrateName()
-	expectedResult := "fizz_buzz"
-
-	if crateName != expectedResult {
-		t.Errorf("CrateName() returned the wrong default crate name; expected '%#v', got '%#v'", expectedResult, crateName)
-	}
-}
-
 // Test to make sure dependencies are being picked up correctly.
 func TestDepsTracking(t *testing.T) {
 	ctx := testRust(t, `
 		rust_library_host_static {
 			name: "libstatic",
 			srcs: ["foo.rs"],
+			crate_name: "static",
 		}
 		rust_library_host_shared {
 			name: "libshared",
 			srcs: ["foo.rs"],
+			crate_name: "shared",
 		}
 		rust_library_host_dylib {
 			name: "libdylib",
 			srcs: ["foo.rs"],
+			crate_name: "dylib",
 		}
 		rust_library_host_rlib {
 			name: "librlib",
 			srcs: ["foo.rs"],
+			crate_name: "rlib",
 		}
 		rust_proc_macro {
 			name: "libpm",
 			srcs: ["foo.rs"],
+			crate_name: "pm",
 		}
 		rust_binary_host {
 			name: "fizz-buzz",
@@ -208,11 +197,13 @@ func TestProcMacroDeviceDeps(t *testing.T) {
 		rust_library_host_rlib {
 			name: "libbar",
 			srcs: ["foo.rs"],
+			crate_name: "bar",
 		}
 		rust_proc_macro {
 			name: "libpm",
 			rlibs: ["libbar"],
 			srcs: ["foo.rs"],
+			crate_name: "pm",
 		}
 		rust_binary {
 			name: "fizz-buzz",