[K/N] Add -Xforce-compiler-driver=(static, dynamic) flag

Useful for development purposes when one wants to compare
the outputs of different drivers.

kotlin-native/backend.native/cli.bc/src/org/jetbrains/kotlin/cli/bc/K2Native.kt

@@ -370,6 +370,7 @@ class K2Native : CLICompiler<K2NativeCompilerArguments>() {
                 arguments.testDumpOutputPath?.let { put(TEST_DUMP_OUTPUT_PATH, it) }
                 put(PARTIAL_LINKAGE, arguments.partialLinkage)
                 put(OMIT_FRAMEWORK_BINARY, arguments.omitFrameworkBinary)
+                putIfNotNull(FORCE_COMPILER_DRIVER, arguments.forceCompilerDriver)
             }
         }
     }

kotlin-native/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/KonanConfigurationKeys.kt

@@ -177,6 +177,7 @@ class KonanConfigKeys {
         val PARTIAL_LINKAGE: CompilerConfigurationKey<Boolean> = CompilerConfigurationKey.create("allows some symbols in klibs be missed")
         val TEST_DUMP_OUTPUT_PATH: CompilerConfigurationKey<String?> = CompilerConfigurationKey.create("path to a file to dump the list of all available tests")
         val OMIT_FRAMEWORK_BINARY: CompilerConfigurationKey<Boolean> = CompilerConfigurationKey.create("do not generate binary in framework")
+        val FORCE_COMPILER_DRIVER: CompilerConfigurationKey<String?> = CompilerConfigurationKey.create("explicitly pick compiler driver")
     }
 }
 

kotlin-native/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/KonanDriver.kt

@@ -38,7 +38,7 @@ class KonanDriver(val project: Project, val environment: KotlinCoreEnvironment,
 
         val konanConfig = KonanConfig(project, configuration)
         ensureModuleName(konanConfig)
-        pickCompilerDriver().run(konanConfig, environment)
+        pickCompilerDriver(konanConfig).run(konanConfig, environment)
     }
 
     private fun ensureModuleName(config: KonanConfig) {
@@ -53,7 +53,14 @@ class KonanDriver(val project: Project, val environment: KotlinCoreEnvironment,
         }
     }
 
-    private fun pickCompilerDriver(): CompilerDriver {
+    private fun pickCompilerDriver(config: KonanConfig): CompilerDriver {
+        config.configuration[KonanConfigKeys.FORCE_COMPILER_DRIVER]?.let {
+            return when (it) {
+                "dynamic" -> DynamicCompilerDriver()
+                "static" -> StaticCompilerDriver()
+                else -> error("Unknown compiler driver. Possible values: dynamic, static")
+            }
+        }
         // Dynamic driver is WIP, so it might not support all possible configurations.
         return if (DynamicCompilerDriver.supportsConfig()) {
             DynamicCompilerDriver()