asm: Pass package path with -p

This is required to produce linkable objects as of Go 1.19.

go/tools/builders/BUILD.bazel

@@ -42,6 +42,8 @@ filegroup(
     srcs = [
         "ar.go",
         "asm.go",
+        "asm_go1.go",
+        "asm_go119.go",
         "builder.go",
         "cgo2.go",
         "compile.go",

go/tools/builders/asm.go

@@ -60,7 +60,10 @@ func asm(args []string) error {
 	}
 
 	// Build source with the assembler.
-	return asmFile(goenv, source, asmFlags, outPath)
+	// Note: As of Go 1.19, this would require a valid package path to work.
+	// But since this functionality is only used by the deprecated action API,
+	// we won't fix this.
+	return asmFile(goenv, source, "", asmFlags, outPath)
 }
 
 // buildSymabisFile generates a file from assembly files that is consumed
@@ -137,9 +140,10 @@ func buildSymabisFile(goenv *env, sFiles, hFiles []fileInfo, asmhdr string) (str
 	return symabisName, err
 }
 
-func asmFile(goenv *env, srcPath string, asmFlags []string, outPath string) error {
+func asmFile(goenv *env, srcPath, packagePath string, asmFlags []string, outPath string) error {
 	args := goenv.goTool("asm")
 	args = append(args, asmFlags...)
+	args = asmAddPackagePathArg(args, packagePath)
 	args = append(args, "-trimpath", ".")
 	args = append(args, "-o", outPath)
 	args = append(args, "--", srcPath)

go/tools/builders/asm_go1.go

@@ -0,0 +1,8 @@
+//go:build !go1.19
+
+package main
+
+func asmAddPackagePathArg(args []string, packagePath string) []string {
+	// go tool asm does neither support nor require the -p arg in Go < 1.19.
+	return args
+}

go/tools/builders/asm_go119.go

@@ -0,0 +1,10 @@
+//go:build go1.19
+
+package main
+
+func asmAddPackagePathArg(args []string, packagePath string) []string {
+	if packagePath != "" {
+		args = append(args, "-p", packagePath)
+	}
+	return args
+}

go/tools/builders/compilepkg.go

@@ -474,7 +474,7 @@ func compileArchive(
 		}
 		for i, sSrc := range srcs.sSrcs {
 			obj := filepath.Join(workDir, fmt.Sprintf("s%d.o", i))
-			if err := asmFile(goenv, sSrc.filename, asmFlags, obj); err != nil {
+			if err := asmFile(goenv, sSrc.filename, packagePath, asmFlags, obj); err != nil {
 				return err
 			}
 			objFiles = append(objFiles, obj)