Add a stand-alone devirtualizer pass.

Add back a stand-alone devirtualizer pass, running prior to generic
specialization. As with the stand-alone generic specializer pass, this
may add functions to the pass manager's work list.

This is another step in unbundling these passes from the performance
inliner.

include/swift/SILOptimizer/PassManager/Passes.def

@@ -75,6 +75,7 @@ PASS(DeadObjectElimination, "deadobject-elim",
      "Eliminate unused objects that do not have destructors with side effects")
 PASS(DefiniteInitialization, "definite-init",
      "Definite Initialization")
+PASS(Devirtualizer, "devirtualizer", "Devirtualize indirect calls")
 PASS(DiagnoseUnreachable, "diagnose-unreachable",
      "Diagnose Unreachable Code")
 PASS(DiagnosticConstantPropagation, "diagnostic-constant-propagation",

lib/SILOptimizer/PassManager/Passes.cpp

@@ -251,6 +251,7 @@ void swift::runSILOptimizationPasses(SILModule &Module) {
 
   // Run two iterations of the high-level SSA passes.
   PM.setStageName("HighLevel");
+  PM.addDevirtualizer();
   PM.addGenericSpecializer();
   AddSSAPasses(PM, OptimizationLevelKind::HighLevel);
   PM.runOneIteration();

lib/SILOptimizer/Transforms/CMakeLists.txt

@@ -7,6 +7,7 @@ set(TRANSFORMS_SOURCES
   Transforms/DeadCodeElimination.cpp
   Transforms/DeadObjectElimination.cpp
   Transforms/DeadStoreElimination.cpp
+  Transforms/Devirtualizer.cpp
   Transforms/GenericSpecializer.cpp
   Transforms/MergeCondFail.cpp
   Transforms/RedundantLoadElimination.cpp

lib/SILOptimizer/Transforms/Devirtualizer.cpp

@@ -0,0 +1,99 @@
+//===-------- Devirtualizer.cpp - Devirtualize indirect calls  ------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2015 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See http://swift.org/LICENSE.txt for license information
+// See http://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+//
+// Devirtualize indirect calls to functions, turning them into direct function
+// references.
+//
+//===----------------------------------------------------------------------===//
+
+#define DEBUG_TYPE "sil-devirtualizer"
+
+#include "swift/SIL/SILFunction.h"
+#include "swift/SIL/SILInstruction.h"
+#include "swift/SILOptimizer/Analysis/ClassHierarchyAnalysis.h"
+#include "swift/SILOptimizer/Utils/Devirtualize.h"
+#include "swift/SILOptimizer/PassManager/Transforms.h"
+#include "llvm/ADT/SmallVector.h"
+
+using namespace swift;
+
+namespace {
+
+class Devirtualizer : public SILFunctionTransform {
+
+  bool devirtualizeAppliesInFunction(SILFunction &F,
+                                     ClassHierarchyAnalysis *CHA);
+
+  /// The entry point to the transformation.
+  void run() override {
+    SILFunction &F = *getFunction();
+    ClassHierarchyAnalysis *CHA = PM->getAnalysis<ClassHierarchyAnalysis>();
+    DEBUG(llvm::dbgs() << "***** Devirtualizer on function:" << F.getName()
+                       << " *****\n");
+
+    if (devirtualizeAppliesInFunction(F, CHA))
+      invalidateAnalysis(SILAnalysis::InvalidationKind::FunctionBody);
+  }
+
+  StringRef getName() override { return "Devirtualizer"; }
+};
+
+} // end anonymous namespace
+
+bool Devirtualizer::devirtualizeAppliesInFunction(SILFunction &F,
+                                                  ClassHierarchyAnalysis *CHA) {
+  bool Changed = false;
+  llvm::SmallVector<SILInstruction *, 8> DeadApplies;
+
+  for (auto &BB : F) {
+    for (auto It = BB.begin(), End = BB.end(); It != End;) {
+      auto &I = *It++;
+
+      // Skip non-apply instructions.
+
+      auto Apply = FullApplySite::isa(&I);
+      if (!Apply)
+        continue;
+
+      auto NewInstPair = tryDevirtualizeApply(Apply, CHA);
+      if (!NewInstPair.second)
+        continue;
+
+      Changed = true;
+
+      auto *CalleeFn = NewInstPair.second.getCalleeFunction();
+      assert(CalleeFn && "Expected devirtualized callee!");
+
+      // We may not have optimized these functions yet, and it could
+      // be beneficial to rerun some earlier passes on the current
+      // function now that we've made these direct references visible.
+      if (CalleeFn->isDefinition() && CalleeFn->shouldOptimize())
+        notifyPassManagerOfFunction(CalleeFn);
+
+      auto *AI = Apply.getInstruction();
+      if (!isa<TryApplyInst>(AI))
+        AI->replaceAllUsesWith(NewInstPair.first);
+
+      DeadApplies.push_back(AI);
+    }
+  }
+
+  // Remove all the now-dead applies.
+  while (!DeadApplies.empty()) {
+    auto *AI = DeadApplies.pop_back_val();
+    recursivelyDeleteTriviallyDeadInstructions(AI, true);
+  }
+
+  return Changed;
+}
+
+SILTransform *swift::createDevirtualizer() { return new Devirtualizer(); }

test/SILOptimizer/devirt_access.sil

@@ -1,4 +1,4 @@
-// RUN: %target-sil-opt -enable-sil-verify-all %s -inline | FileCheck %s
+// RUN: %target-sil-opt -enable-sil-verify-all %s -devirtualizer | FileCheck %s
 
 sil_stage canonical
 

test/SILOptimizer/devirt_alloc_ref_dynamic.sil

@@ -1,4 +1,4 @@
-// RUN: %target-sil-opt -enable-sil-verify-all %s -sil-combine -inline -dce | FileCheck %s
+// RUN: %target-sil-opt -enable-sil-verify-all %s -sil-combine -devirtualizer -dce | FileCheck %s
 
 sil_stage canonical
 

test/SILOptimizer/devirt_try_apply.sil

@@ -1,4 +1,4 @@
-// RUN: %target-sil-opt -enable-sil-verify-all %s -sil-combine -inline -redundant-load-elim -inline  | FileCheck %s --check-prefix=CHECK-INLINE
+// RUN: %target-sil-opt -enable-sil-verify-all %s -sil-combine -devirtualizer -redundant-load-elim -inline  | FileCheck %s --check-prefix=CHECK-DEVIRT
 // RUN: %target-sil-opt -enable-sil-verify-all %s -early-inline  | FileCheck %s --check-prefix=CHECK-EARLY-INLINE
 // RUN: %target-sil-opt -enable-sil-verify-all %s -specdevirt  | FileCheck %s --check-prefix=CHECK-SPECDEVIRT
 // RUN: %target-sil-opt -enable-sil-verify-all %s -mandatory-inlining  | FileCheck %s --check-prefix=CHECK-MANDATORY-INLINING
@@ -615,10 +615,10 @@ bb0:
 // CHECK-SPECDEVIRT: checked_cast_br [exact]
 // CHECK-SPECDEVIRT: }
 
-// CHECK-INLINE-LABEL: sil @_TF16devirt_try_apply5test4FT_Vs5Int32
-// CHECK-INLINE-NOT: checked_cast_br [exact]
-// CHECK-INLINE-NOT: class_method
-// CHECK-INLINE: }
+// CHECK-DEVIRT-LABEL: sil @_TF16devirt_try_apply5test4FT_Vs5Int32
+// CHECK-DEVIRT-NOT: checked_cast_br [exact]
+// CHECK-DEVIRT-NOT: class_method
+// CHECK-DEVIRT: }
 
 // CHECK-EARLY-INLINE-LABEL: sil @_TF16devirt_try_apply5test4FT_Vs5Int32
 // CHECK-EARLY-INLINE-NOT: checked_cast_br [exact]
@@ -658,10 +658,10 @@ bb4(%19 : $ErrorType):
 
 // DISABLE THIS TEST CASE FOR NOW. AS RLE GETS BETTER. WILL RE-ENABLE.
 //
-// DISABLECHECK-INLINE-LABEL: sil @_TF16devirt_try_apply5test5FT_Vs5Int32
-// DISABLECHECK-INLINE-NOT: = witness_method
-// DISABLECHECK-INLINE-NOT: = class_method
-// DISABLECHECK-INLINE: }
+// DISABLECHECK-DEVIRT-LABEL: sil @_TF16devirt_try_apply5test5FT_Vs5Int32
+// DISABLECHECK-DEVIRT-NOT: = witness_method
+// DISABLECHECK-DEVIRT-NOT: = class_method
+// DISABLECHECK-DEVIRT: }
 sil @_TF16devirt_try_apply5test5FT_Vs5Int32 : $@convention(thin) () -> Int32 {
 bb0:
   %0 = alloc_stack $Int32
@@ -705,9 +705,9 @@ bb4(%23 : $ErrorType):
 // CHECK-SPECDEVIRT: checked_cast_br [exact]
 // CHECK-SPECDEVIRT: }
 
-// CHECK-INLINE-LABEL: sil @_TF16devirt_try_apply5test6FT_GSqVs5Int32_
-// CHECK-INLINE-NOT: class_method
-// CHECK-INLINE: }
+// CHECK-DEVIRT-LABEL: sil @_TF16devirt_try_apply5test6FT_GSqVs5Int32_
+// CHECK-DEVIRT-NOT: class_method
+// CHECK-DEVIRT: }
 
 // CHECK-EARLY-INLINE-LABEL: sil @_TF16devirt_try_apply5test6FT_GSqVs5Int32_
 // CHECK-EARLY-INLINE-NOT: class_method
@@ -751,10 +751,10 @@ bb4(%20 : $ErrorType):
 // CHECK-SPECDEVIRT: checked_cast_br [exact]
 // CHECK-SPECDEVIRT: }
 
-// CHECK-INLINE-LABEL: sil @_TF16devirt_try_apply5test7FT_Vs5Int32
-// CHECK-INLINE-NOT: checked_cast_br [exact]
-// CHECK-INLINE-NOT: class_method
-// CHECK-INLINE: }
+// CHECK-DEVIRT-LABEL: sil @_TF16devirt_try_apply5test7FT_Vs5Int32
+// CHECK-DEVIRT-NOT: checked_cast_br [exact]
+// CHECK-DEVIRT-NOT: class_method
+// CHECK-DEVIRT: }
 
 // CHECK-EARLY-INLINE-LABEL: sil @_TF16devirt_try_apply5test7FT_Vs5Int32
 // CHECK-EARLY-INLINE-NOT: checked_cast_br [exact]

test/SILOptimizer/devirtualize.sil

@@ -1,4 +1,4 @@
-// RUN: %target-sil-opt -enable-sil-verify-all %s -inline -dce | FileCheck %s
+// RUN: %target-sil-opt -enable-sil-verify-all %s -devirtualizer -dce | FileCheck %s
 
 sil_stage canonical
 

test/SILOptimizer/devirtualize2.sil

@@ -1,4 +1,4 @@
-// RUN: %target-sil-opt -enable-sil-verify-all %s -inline -dce | FileCheck %s
+// RUN: %target-sil-opt -enable-sil-verify-all %s -devirtualizer -dce | FileCheck %s
 
 sil_stage canonical