More precise control over backend phases

Refactor backend phases invocation to make it possible to
disable LLVM optimization pipeline. Also it makes phases separation a bit more clear.

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

@@ -86,6 +86,25 @@ private fun insertAliasToEntryPoint(context: Context) {
     LLVMAddAlias(module, LLVMTypeOf(entryPoint)!!, entryPoint, "main")
 }
 
+internal fun linkBitcodeDependencies(context: Context) {
+    val config = context.config.configuration
+    val tempFiles = context.config.tempFiles
+    val produce = config.get(KonanConfigKeys.PRODUCE)
+
+    val generatedBitcodeFiles =
+            if (produce == CompilerOutputKind.DYNAMIC || produce == CompilerOutputKind.STATIC) {
+                produceCAdapterBitcode(
+                        context.config.clang,
+                        tempFiles.cAdapterCppName,
+                        tempFiles.cAdapterBitcodeName)
+                listOf(tempFiles.cAdapterBitcodeName)
+            } else emptyList()
+    if (produce == CompilerOutputKind.FRAMEWORK && context.config.produceStaticFramework) {
+        embedAppleLinkerOptionsToBitcode(context.llvm, context.config)
+    }
+    linkAllDependencies(context, generatedBitcodeFiles)
+}
+
 internal fun produceOutput(context: Context) {
 
     val config = context.config.configuration
@@ -101,19 +120,6 @@ internal fun produceOutput(context: Context) {
         CompilerOutputKind.PROGRAM -> {
             val output = tempFiles.nativeBinaryFileName
             context.bitcodeFileName = output
-            val generatedBitcodeFiles =
-                if (produce == CompilerOutputKind.DYNAMIC || produce == CompilerOutputKind.STATIC) {
-                    produceCAdapterBitcode(
-                        context.config.clang,
-                        tempFiles.cAdapterCppName,
-                        tempFiles.cAdapterBitcodeName)
-                    listOf(tempFiles.cAdapterBitcodeName)
-                } else emptyList()
-            if (produce == CompilerOutputKind.FRAMEWORK && context.config.produceStaticFramework) {
-                embedAppleLinkerOptionsToBitcode(context.llvm, context.config)
-            }
-            linkAllDependencies(context, generatedBitcodeFiles)
-            runLlvmOptimizationPipeline(context)
             // Insert `_main` after pipeline so we won't worry about optimizations
             // corrupting entry point.
             insertAliasToEntryPoint(context)

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

@@ -271,13 +271,6 @@ internal val linkerPhase = konanUnitPhase(
         description = "Linker"
 )
 
-internal val linkPhase = namedUnitPhase(
-        name = "Link",
-        description = "Link stage",
-        lower = objectFilesPhase then
-                linkerPhase
-)
-
 internal val allLoweringsPhase = namedIrModulePhase(
         name = "IrLowering",
         description = "IR Lowering",
@@ -428,11 +421,14 @@ val toplevelPhase: CompilerPhase<*, Unit, Unit> = namedUnitPhase(
                                 bitcodePhase then
                                 verifyBitcodePhase then
                                 printBitcodePhase then
+                                linkBitcodeDependenciesPhase then
+                                bitcodeOptimizationPhase then
                                 produceOutputPhase then
                                 disposeLLVMPhase then
                                 unitSink()
                 ) then
-                linkPhase
+                objectFilesPhase then
+                linkerPhase
 )
 
 internal fun PhaseConfig.disableIf(phase: AnyNamedPhase, condition: Boolean) {
@@ -455,7 +451,10 @@ internal fun PhaseConfig.konanPhasesConfig(config: KonanConfig) {
         disableIf(dependenciesLowerPhase, config.produce == CompilerOutputKind.LIBRARY)
         disableUnless(entryPointPhase, config.produce == CompilerOutputKind.PROGRAM)
         disableIf(bitcodePhase, config.produce == CompilerOutputKind.LIBRARY)
-        disableUnless(linkPhase, config.produce.involvesLinkStage)
+        disableUnless(bitcodeOptimizationPhase, config.produce.involvesLinkStage)
+        disableUnless(linkBitcodeDependenciesPhase, config.produce.involvesLinkStage)
+        disableUnless(objectFilesPhase, config.produce.involvesLinkStage)
+        disableUnless(linkerPhase, config.produce.involvesLinkStage)
         disableIf(testProcessorPhase, getNotNull(KonanConfigKeys.GENERATE_TEST_RUNNER) == TestRunnerKind.NONE)
         disableUnless(buildDFGPhase, getBoolean(KonanConfigKeys.OPTIMIZATION))
         disableUnless(devirtualizationPhase, getBoolean(KonanConfigKeys.OPTIMIZATION))

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

@@ -244,6 +244,18 @@ internal val cStubsPhase = makeKonanModuleOpPhase(
         op = { context, _ -> produceCStubs(context) }
 )
 
+internal val linkBitcodeDependenciesPhase = makeKonanModuleOpPhase(
+        name = "LinkBitcodeDependencies",
+        description = "Link bitcode dependencies",
+        op = { context, _ -> linkBitcodeDependencies(context) }
+)
+
+internal val bitcodeOptimizationPhase = makeKonanModuleOpPhase(
+        name = "BitcodeOptimization",
+        description = "Optimize bitcode",
+        op = { context, _ -> runLlvmOptimizationPipeline(context) }
+)
+
 internal val produceOutputPhase = makeKonanModuleOpPhase(
         name = "ProduceOutput",
         description = "Produce output",