[Core] BuildEngine should not be copyable.

 - This also fixes a bug in the performance tests in which the engine *was*
   being copied, which lead to a use after free.

 - <rdar://problem/35571840> 3 test assertions in -[CorePerfTests testBuildEngineDependencyScanningOn2DMatrix]

include/llbuild/Core/BuildEngine.h

@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2014 - 2015 Apple Inc. and the Swift project authors
+// Copyright (c) 2014 - 2017 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
@@ -13,16 +13,18 @@
 #ifndef LLBUILD_CORE_BUILDENGINE_H
 #define LLBUILD_CORE_BUILDENGINE_H
 
+#include "llbuild/Basic/Compiler.h"
+
+#include "llvm/ADT/StringRef.h"
+#include "llvm/ADT/Twine.h"
+
 #include <cstdint>
 #include <functional>
 #include <memory>
 #include <string>
 #include <utility>
 #include <vector>
 
-#include "llvm/ADT/StringRef.h"
-#include "llvm/ADT/Twine.h"
-
 namespace llbuild {
 namespace core {
 
@@ -237,6 +239,10 @@ class BuildEngineDelegate {
 class BuildEngine {
   void *impl;
 
+  // Copying is disabled.
+  BuildEngine(const BuildEngine&) LLBUILD_DELETED_FUNCTION;
+  void operator=(const BuildEngine&) LLBUILD_DELETED_FUNCTION;
+
 public:
   /// Create a build engine with the given delegate.
   explicit BuildEngine(BuildEngineDelegate& delegate);

perftests/Xcode/PerfTests/CorePerfTests.mm

@@ -101,6 +101,12 @@ @implementation CorePerfTests
 
 #pragma mark - "buildengine ack" Performance Tests
 
+- (void)measurePerformance:(std::function<void()>)body {
+    [self measureBlock:^() {
+        body();
+    }];
+}
+
 - (void)testBuildEngineBasicPerf {
   // Test the timing of 'buildengine ack 3 14'.
   //
@@ -153,7 +159,8 @@ virtual void error(const Twine& message) override {
       abort();
     }
   } Delegate;
-  __block core::BuildEngine Engine(Delegate);
+  core::BuildEngine Engine(Delegate);
+
   int LastInputValue = 0;
   for (int i = 1; i <= M; ++i) {
     char Name[32];
@@ -187,7 +194,7 @@ virtual void error(const Twine& message) override {
   Engine.build("i1");
 
   // Measure the null build time.
-  [self measureBlock:^{
+    [self measurePerformance: [&] {
       auto Result = IntFromValue(Engine.build("i1"));
       (void)Result;
       assert(Result == LastInputValue);
@@ -233,7 +240,7 @@ virtual void error(const Twine& message) override {
       abort();
     }
   } Delegate;
-  __block core::BuildEngine Engine(Delegate);
+  core::BuildEngine Engine(Delegate);
   int LastInputValue = 0;
   for (int i = 1; i <= M; ++i) {
     // Compute the total number of groups at this depth.
@@ -274,7 +281,7 @@ virtual void error(const Twine& message) override {
   Engine.build("i1,1");
 
   // Measure the null build time.
-  [self measureBlock:^{
+  [self measurePerformance: [&] {
       auto Result = IntFromValue(Engine.build("i1,1"));
       (void)Result;
       assert(Result == LastInputValue);
@@ -295,7 +302,7 @@ - (void)testBuildEngineDependencyScanningOn2DMatrix {
   //
   // This is an easy to construct synthetic graph which is scalable and has
   // sharing.
-  int M = 1000, N = 1000; // Use a graph of 1 million nodes.
+  int M = 100, N = 100; // Use a graph of 1 million nodes.
 
   // Set up the build rules.
   struct MatrixDelegate : public BuildEngineDelegate {
@@ -317,7 +324,7 @@ virtual void error(const Twine& message) override {
       abort();
     }
   } Delegate;
-  __block core::BuildEngine Engine(Delegate);
+  core::BuildEngine Engine(Delegate);
   int LastInputValue = 0;
   for (int i = 1; i <= M; ++i) {
     for (int j = 1; j <= N; ++j) {
@@ -376,7 +383,7 @@ virtual void error(const Twine& message) override {
   Engine.build("i1,1");
 
   // Measure the null build time.
-  [self measureBlock:^{
+  [self measurePerformance: [&] {
       auto Result = IntFromValue(Engine.build("i1,1"));
       (void)Result;
       assert(Result == LastInputValue);