[K/N] Add option to save unoptimized bitcode

Add `-Xsave-llvm-ir` option that stores LLVM IR text into temporary
directory right after IrToBitcode translation. This is required for
FileCheck-based tests and just helpful during development.

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

@@ -175,6 +175,7 @@ class K2Native : CLICompiler<K2NativeCompilerArguments>() {
                 arguments.manifestFile ?.let{ put(MANIFEST_FILE, it) }
                 arguments.runtimeFile ?.let{ put(RUNTIME_FILE, it) }
                 arguments.temporaryFilesDir?.let { put(TEMPORARY_FILES_DIR, it) }
+                put(SAVE_LLVM_IR, arguments.saveLlvmIr)
 
                 put(LIST_TARGETS, arguments.listTargets)
                 put(OPTIMIZATION, arguments.optimization)

kotlin-native/backend.native/cli.bc/src/org/jetbrains/kotlin/cli/bc/K2NativeCompilerArguments.kt

@@ -255,6 +255,9 @@ class K2NativeCompilerArguments : CommonCompilerArguments() {
     @Argument(value = "-Xtemporary-files-dir", deprecatedName = "--temporary_files_dir", valueDescription = "<path>", description = "Save temporary files to the given directory")
     var temporaryFilesDir: String? = null
 
+    @Argument(value = "-Xsave-llvm-ir", description = "Save result of Kotlin IR to LLVM IR translation to the temporary files directory.")
+    var saveLlvmIr: Boolean = false
+
     @Argument(value = "-Xverify-bitcode", deprecatedName = "--verify_bitcode", description = "Verify llvm bitcode after each method")
     var verifyBitCode: Boolean = false
 

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

@@ -134,6 +134,8 @@ class KonanConfigKeys {
                 = CompilerConfigurationKey.create("target we compile for")
         val TEMPORARY_FILES_DIR: CompilerConfigurationKey<String?>
                 = CompilerConfigurationKey.create("directory for temporary files")
+        val SAVE_LLVM_IR: CompilerConfigurationKey<Boolean>
+                = CompilerConfigurationKey.create("save LLVM IR")
         val VERIFY_BITCODE: CompilerConfigurationKey<Boolean>
                 = CompilerConfigurationKey.create("verify bitcode")
         val VERIFY_IR: CompilerConfigurationKey<Boolean>

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

@@ -5,6 +5,10 @@
 
 package org.jetbrains.kotlin.backend.konan.llvm
 
+import kotlinx.cinterop.alloc
+import kotlinx.cinterop.memScoped
+import kotlinx.cinterop.ptr
+import kotlinx.cinterop.toKStringFromUtf8
 import llvm.*
 import org.jetbrains.kotlin.backend.common.phaser.CompilerPhase
 import org.jetbrains.kotlin.backend.common.phaser.PhaseConfig
@@ -12,7 +16,6 @@ import org.jetbrains.kotlin.backend.common.phaser.PhaserState
 import org.jetbrains.kotlin.backend.common.phaser.namedUnitPhase
 import org.jetbrains.kotlin.backend.konan.*
 import org.jetbrains.kotlin.backend.konan.descriptors.GlobalHierarchyAnalysis
-import org.jetbrains.kotlin.backend.konan.lower.DECLARATION_ORIGIN_BRIDGE_METHOD
 import org.jetbrains.kotlin.backend.konan.lower.InlineClassPropertyAccessorsLowering
 import org.jetbrains.kotlin.backend.konan.lower.RedundantCoercionsCleaner
 import org.jetbrains.kotlin.backend.konan.lower.ReturnsInsertionLowering
@@ -27,7 +30,6 @@ import org.jetbrains.kotlin.ir.util.parentAsClass
 import org.jetbrains.kotlin.ir.visitors.*
 import org.jetbrains.kotlin.util.OperatorNameConventions
 import org.jetbrains.kotlin.utils.addToStdlib.cast
-import org.jetbrains.kotlin.utils.addToStdlib.safeAs
 
 internal val contextLLVMSetupPhase = makeKonanModuleOpPhase(
         name = "ContextLLVMSetup",
@@ -325,6 +327,17 @@ internal val codegenPhase = makeKonanModuleOpPhase(
         description = "Code generation",
         op = { context, irModule ->
             irModule.acceptVoid(context.codegenVisitor)
+            // TODO: Consider adding LLVM_IR compiler output kind.
+            if (context.configuration.getBoolean(KonanConfigKeys.SAVE_LLVM_IR)) {
+                val moduleName: String = memScoped {
+                    val sizeVar = alloc<size_tVar>()
+                    LLVMGetModuleIdentifier(context.llvmModule, sizeVar.ptr)!!.toKStringFromUtf8()
+                }
+                val output = context.config.tempFiles.create(moduleName,".ll")
+                if (LLVMPrintModuleToFile(context.llvmModule, output.absolutePath, null) != 0) {
+                    error("Can't dump LLVM IR to ${output.absolutePath}")
+                }
+            }
         }
 )