[llvm] [ADT] Add a missing call to a unique_function destructor after move (PR #98747)

David Blaikie via llvm-commits llvm-commits at lists.llvm.org
Mon Aug 19 11:57:52 PDT 2024


https://github.com/dwblaikie updated https://github.com/llvm/llvm-project/pull/98747

>From 9ed5469feed836b3666732207fd903b12f492a27 Mon Sep 17 00:00:00 2001
From: Dmitry Yanovsky <kerambyte at gmail.com>
Date: Sat, 13 Jul 2024 15:45:18 +0100
Subject: [PATCH 1/7] [ADT] Add a missing call to a unique_function destructor
 after move

Right now immediately after moving the captured state, we `disarm` the moved-from object's destructor by resetting the `RHS.CallbackAndInlineFlag`. This means that we never properly destroy the RHS object's captured state.
---
 llvm/include/llvm/ADT/FunctionExtras.h | 1 +
 1 file changed, 1 insertion(+)

diff --git a/llvm/include/llvm/ADT/FunctionExtras.h b/llvm/include/llvm/ADT/FunctionExtras.h
index 49e0e8ab0db400..38a3829fb51376 100644
--- a/llvm/include/llvm/ADT/FunctionExtras.h
+++ b/llvm/include/llvm/ADT/FunctionExtras.h
@@ -312,6 +312,7 @@ template <typename ReturnT, typename... ParamTs> class UniqueFunctionBase {
       // Non-trivial move, so dispatch to a type-erased implementation.
       getNonTrivialCallbacks()->MovePtr(getInlineStorage(),
                                         RHS.getInlineStorage());
+      getNonTrivialCallbacks()->DestroyPtr(RHS.getInlineStorage());
     }
 
     // Clear the old callback and inline flag to get back to as-if-null.

>From 72c19829da13bb0bca25ea617a56ac5960c6fb9e Mon Sep 17 00:00:00 2001
From: kerambyte <kerambyte at gmail.com>
Date: Mon, 15 Jul 2024 13:03:51 +0100
Subject: [PATCH 2/7] add a unit test

---
 llvm/unittests/ADT/FunctionExtrasTest.cpp | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/llvm/unittests/ADT/FunctionExtrasTest.cpp b/llvm/unittests/ADT/FunctionExtrasTest.cpp
index fc856a976946bf..80f7f3cf55665e 100644
--- a/llvm/unittests/ADT/FunctionExtrasTest.cpp
+++ b/llvm/unittests/ADT/FunctionExtrasTest.cpp
@@ -310,4 +310,22 @@ class Incomplete {};
 Incomplete incompleteFunction() { return {}; }
 const Incomplete incompleteFunctionConst() { return {}; }
 
+// Check that the moved-from captured state is properly destroyed during
+// move construction/assignment.
+TEST(UniqueFunctionTest, MovedFromStateIsDestroyedCorrectly) {
+  static int NumOfDestructorsCalled = 0;
+  struct State {
+    State() = default;
+    State(State &&) = default;
+    State &operator=(State &&) = default;
+    ~State() { ++NumOfDestructorsCalled; }
+  };
+  {
+    unique_function<void()> CapturingFunction{[state = State{}] {}};
+    unique_function<void()> CapturingFunctionMoved{
+        std::move(CapturingFunction)};
+  }
+  EXPECT_EQ(NumOfDestructorsCalled, 4);
+}
+
 } // anonymous namespace

>From 0442dbd1a5ddb29c6c1c204181b84d98384c39fd Mon Sep 17 00:00:00 2001
From: kerambyte <kerambyte at gmail.com>
Date: Mon, 15 Jul 2024 17:13:54 +0100
Subject: [PATCH 3/7] refactor the test

---
 llvm/unittests/ADT/FunctionExtrasTest.cpp | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/llvm/unittests/ADT/FunctionExtrasTest.cpp b/llvm/unittests/ADT/FunctionExtrasTest.cpp
index 80f7f3cf55665e..01cdf499ac100c 100644
--- a/llvm/unittests/ADT/FunctionExtrasTest.cpp
+++ b/llvm/unittests/ADT/FunctionExtrasTest.cpp
@@ -313,11 +313,14 @@ const Incomplete incompleteFunctionConst() { return {}; }
 // Check that the moved-from captured state is properly destroyed during
 // move construction/assignment.
 TEST(UniqueFunctionTest, MovedFromStateIsDestroyedCorrectly) {
+  static int NumOfMovesCalled = 0;
   static int NumOfDestructorsCalled = 0;
   struct State {
     State() = default;
-    State(State &&) = default;
-    State &operator=(State &&) = default;
+    State(const State &) = delete;
+    State(State &&) { ++NumOfMovesCalled; }
+    State &operator=(const State &) = delete;
+    State &operator=(State &&Rhs) { return *new (this) State{std::move(Rhs)}; }
     ~State() { ++NumOfDestructorsCalled; }
   };
   {
@@ -325,7 +328,7 @@ TEST(UniqueFunctionTest, MovedFromStateIsDestroyedCorrectly) {
     unique_function<void()> CapturingFunctionMoved{
         std::move(CapturingFunction)};
   }
-  EXPECT_EQ(NumOfDestructorsCalled, 4);
+  EXPECT_EQ(NumOfDestructorsCalled, 1 + NumOfMovesCalled);
 }
 
 } // anonymous namespace

>From 8348a98aeb4b2687d98d1a07d190c3d154db5e7c Mon Sep 17 00:00:00 2001
From: kerambyte <kerambyte at gmail.com>
Date: Mon, 15 Jul 2024 17:26:49 +0100
Subject: [PATCH 4/7] cleanup

---
 llvm/unittests/ADT/FunctionExtrasTest.cpp | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/llvm/unittests/ADT/FunctionExtrasTest.cpp b/llvm/unittests/ADT/FunctionExtrasTest.cpp
index 01cdf499ac100c..23be6be037aa9d 100644
--- a/llvm/unittests/ADT/FunctionExtrasTest.cpp
+++ b/llvm/unittests/ADT/FunctionExtrasTest.cpp
@@ -317,10 +317,7 @@ TEST(UniqueFunctionTest, MovedFromStateIsDestroyedCorrectly) {
   static int NumOfDestructorsCalled = 0;
   struct State {
     State() = default;
-    State(const State &) = delete;
     State(State &&) { ++NumOfMovesCalled; }
-    State &operator=(const State &) = delete;
-    State &operator=(State &&Rhs) { return *new (this) State{std::move(Rhs)}; }
     ~State() { ++NumOfDestructorsCalled; }
   };
   {
@@ -328,6 +325,7 @@ TEST(UniqueFunctionTest, MovedFromStateIsDestroyedCorrectly) {
     unique_function<void()> CapturingFunctionMoved{
         std::move(CapturingFunction)};
   }
+  printf("%i, %i\n", NumOfMovesCalled, NumOfDestructorsCalled);
   EXPECT_EQ(NumOfDestructorsCalled, 1 + NumOfMovesCalled);
 }
 

>From 56f4cee7852c9d2d027308fb58846f662514007a Mon Sep 17 00:00:00 2001
From: kerambyte <kerambyte at gmail.com>
Date: Tue, 16 Jul 2024 10:00:55 +0100
Subject: [PATCH 5/7] refactor the test and fix alignment issue

---
 llvm/include/llvm/ADT/FunctionExtras.h    |  6 ++++--
 llvm/unittests/ADT/CountCopyAndMove.cpp   |  1 +
 llvm/unittests/ADT/CountCopyAndMove.h     | 10 ++++++++--
 llvm/unittests/ADT/FunctionExtrasTest.cpp | 16 ++++++----------
 4 files changed, 19 insertions(+), 14 deletions(-)

diff --git a/llvm/include/llvm/ADT/FunctionExtras.h b/llvm/include/llvm/ADT/FunctionExtras.h
index 38a3829fb51376..d92868e3715f40 100644
--- a/llvm/include/llvm/ADT/FunctionExtras.h
+++ b/llvm/include/llvm/ADT/FunctionExtras.h
@@ -80,6 +80,7 @@ using EnableIfCallable = std::enable_if_t<std::disjunction<
 template <typename ReturnT, typename... ParamTs> class UniqueFunctionBase {
 protected:
   static constexpr size_t InlineStorageSize = sizeof(void *) * 3;
+  static constexpr size_t InlineStorageAlign = alignof(void *);
 
   template <typename T, class = void>
   struct IsSizeLessThanThresholdT : std::false_type {};
@@ -161,7 +162,8 @@ template <typename ReturnT, typename... ParamTs> class UniqueFunctionBase {
     // provide three pointers worth of storage here.
     // This is mutable as an inlined `const unique_function<void() const>` may
     // still modify its own mutable members.
-    alignas(void *) mutable std::byte InlineStorage[InlineStorageSize];
+    alignas(InlineStorageAlign) mutable std::byte
+        InlineStorage[InlineStorageSize];
   } StorageUnion;
 
   // A compressed pointer to either our dispatching callback or our table of
@@ -262,7 +264,7 @@ template <typename ReturnT, typename... ParamTs> class UniqueFunctionBase {
     bool IsInlineStorage = true;
     void *CallableAddr = getInlineStorage();
     if (sizeof(CallableT) > InlineStorageSize ||
-        alignof(CallableT) > alignof(decltype(StorageUnion.InlineStorage))) {
+        alignof(CallableT) > InlineStorageAlign) {
       IsInlineStorage = false;
       // Allocate out-of-line storage. FIXME: Use an explicit alignment
       // parameter in C++17 mode.
diff --git a/llvm/unittests/ADT/CountCopyAndMove.cpp b/llvm/unittests/ADT/CountCopyAndMove.cpp
index fe1e2f4a5b89fd..f6f657388048d3 100644
--- a/llvm/unittests/ADT/CountCopyAndMove.cpp
+++ b/llvm/unittests/ADT/CountCopyAndMove.cpp
@@ -10,6 +10,7 @@
 
 using namespace llvm;
 
+int CountCopyAndMove::Constructions = 0;
 int CountCopyAndMove::CopyConstructions = 0;
 int CountCopyAndMove::CopyAssignments = 0;
 int CountCopyAndMove::MoveConstructions = 0;
diff --git a/llvm/unittests/ADT/CountCopyAndMove.h b/llvm/unittests/ADT/CountCopyAndMove.h
index 126054427b81a3..390a59a2e3f146 100644
--- a/llvm/unittests/ADT/CountCopyAndMove.h
+++ b/llvm/unittests/ADT/CountCopyAndMove.h
@@ -12,6 +12,7 @@
 namespace llvm {
 
 struct CountCopyAndMove {
+  static int Constructions;
   static int CopyConstructions;
   static int CopyAssignments;
   static int MoveConstructions;
@@ -19,8 +20,8 @@ struct CountCopyAndMove {
   static int Destructions;
   int val;
 
-  CountCopyAndMove() = default;
-  explicit CountCopyAndMove(int val) : val(val) {}
+  CountCopyAndMove() { ++Constructions; }
+  explicit CountCopyAndMove(int val) : val(val) { ++Constructions; }
   CountCopyAndMove(const CountCopyAndMove &other) : val(other.val) {
     ++CopyConstructions;
   }
@@ -40,6 +41,7 @@ struct CountCopyAndMove {
   ~CountCopyAndMove() { ++Destructions; }
 
   static void ResetCounts() {
+    Constructions = 0;
     CopyConstructions = 0;
     CopyAssignments = 0;
     MoveConstructions = 0;
@@ -47,6 +49,10 @@ struct CountCopyAndMove {
     Destructions = 0;
   }
 
+  static int TotalConstructions() {
+    return Constructions + MoveConstructions + CopyConstructions;
+  }
+
   static int TotalCopies() { return CopyConstructions + CopyAssignments; }
 
   static int TotalMoves() { return MoveConstructions + MoveAssignments; }
diff --git a/llvm/unittests/ADT/FunctionExtrasTest.cpp b/llvm/unittests/ADT/FunctionExtrasTest.cpp
index 23be6be037aa9d..880a18b4481f96 100644
--- a/llvm/unittests/ADT/FunctionExtrasTest.cpp
+++ b/llvm/unittests/ADT/FunctionExtrasTest.cpp
@@ -7,6 +7,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "llvm/ADT/FunctionExtras.h"
+#include "CountCopyAndMove.h"
 #include "gtest/gtest.h"
 
 #include <memory>
@@ -313,20 +314,15 @@ const Incomplete incompleteFunctionConst() { return {}; }
 // Check that the moved-from captured state is properly destroyed during
 // move construction/assignment.
 TEST(UniqueFunctionTest, MovedFromStateIsDestroyedCorrectly) {
-  static int NumOfMovesCalled = 0;
-  static int NumOfDestructorsCalled = 0;
-  struct State {
-    State() = default;
-    State(State &&) { ++NumOfMovesCalled; }
-    ~State() { ++NumOfDestructorsCalled; }
-  };
+  CountCopyAndMove::ResetCounts();
   {
-    unique_function<void()> CapturingFunction{[state = State{}] {}};
+    unique_function<void()> CapturingFunction{
+        [Counter = CountCopyAndMove{}] {}};
     unique_function<void()> CapturingFunctionMoved{
         std::move(CapturingFunction)};
   }
-  printf("%i, %i\n", NumOfMovesCalled, NumOfDestructorsCalled);
-  EXPECT_EQ(NumOfDestructorsCalled, 1 + NumOfMovesCalled);
+  EXPECT_EQ(CountCopyAndMove::TotalConstructions(),
+            CountCopyAndMove::Destructions);
 }
 
 } // anonymous namespace

>From b54974e7ee1b27ac05550189c6c7015be21fcf2c Mon Sep 17 00:00:00 2001
From: kerambyte <kerambyte at gmail.com>
Date: Thu, 18 Jul 2024 00:10:01 +0100
Subject: [PATCH 6/7] remove alignment fix

---
 llvm/include/llvm/ADT/FunctionExtras.h | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/llvm/include/llvm/ADT/FunctionExtras.h b/llvm/include/llvm/ADT/FunctionExtras.h
index d92868e3715f40..38a3829fb51376 100644
--- a/llvm/include/llvm/ADT/FunctionExtras.h
+++ b/llvm/include/llvm/ADT/FunctionExtras.h
@@ -80,7 +80,6 @@ using EnableIfCallable = std::enable_if_t<std::disjunction<
 template <typename ReturnT, typename... ParamTs> class UniqueFunctionBase {
 protected:
   static constexpr size_t InlineStorageSize = sizeof(void *) * 3;
-  static constexpr size_t InlineStorageAlign = alignof(void *);
 
   template <typename T, class = void>
   struct IsSizeLessThanThresholdT : std::false_type {};
@@ -162,8 +161,7 @@ template <typename ReturnT, typename... ParamTs> class UniqueFunctionBase {
     // provide three pointers worth of storage here.
     // This is mutable as an inlined `const unique_function<void() const>` may
     // still modify its own mutable members.
-    alignas(InlineStorageAlign) mutable std::byte
-        InlineStorage[InlineStorageSize];
+    alignas(void *) mutable std::byte InlineStorage[InlineStorageSize];
   } StorageUnion;
 
   // A compressed pointer to either our dispatching callback or our table of
@@ -264,7 +262,7 @@ template <typename ReturnT, typename... ParamTs> class UniqueFunctionBase {
     bool IsInlineStorage = true;
     void *CallableAddr = getInlineStorage();
     if (sizeof(CallableT) > InlineStorageSize ||
-        alignof(CallableT) > InlineStorageAlign) {
+        alignof(CallableT) > alignof(decltype(StorageUnion.InlineStorage))) {
       IsInlineStorage = false;
       // Allocate out-of-line storage. FIXME: Use an explicit alignment
       // parameter in C++17 mode.

>From 04ce60f668470d95ff8c85fe548d9585e249d53c Mon Sep 17 00:00:00 2001
From: kerambyte <kerambyte at gmail.com>
Date: Sun, 11 Aug 2024 10:55:58 +0100
Subject: [PATCH 7/7] update names

---
 llvm/unittests/ADT/CountCopyAndMove.cpp |  3 ++-
 llvm/unittests/ADT/CountCopyAndMove.h   | 12 +++++++-----
 2 files changed, 9 insertions(+), 6 deletions(-)

diff --git a/llvm/unittests/ADT/CountCopyAndMove.cpp b/llvm/unittests/ADT/CountCopyAndMove.cpp
index f6f657388048d3..022dbee40dc6f1 100644
--- a/llvm/unittests/ADT/CountCopyAndMove.cpp
+++ b/llvm/unittests/ADT/CountCopyAndMove.cpp
@@ -10,7 +10,8 @@
 
 using namespace llvm;
 
-int CountCopyAndMove::Constructions = 0;
+int CountCopyAndMove::DefaultConstructions = 0;
+int CountCopyAndMove::ValueConstructions = 0;
 int CountCopyAndMove::CopyConstructions = 0;
 int CountCopyAndMove::CopyAssignments = 0;
 int CountCopyAndMove::MoveConstructions = 0;
diff --git a/llvm/unittests/ADT/CountCopyAndMove.h b/llvm/unittests/ADT/CountCopyAndMove.h
index 390a59a2e3f146..9f5048cc6107d9 100644
--- a/llvm/unittests/ADT/CountCopyAndMove.h
+++ b/llvm/unittests/ADT/CountCopyAndMove.h
@@ -12,7 +12,8 @@
 namespace llvm {
 
 struct CountCopyAndMove {
-  static int Constructions;
+  static int DefaultConstructions;
+  static int ValueConstructions;
   static int CopyConstructions;
   static int CopyAssignments;
   static int MoveConstructions;
@@ -20,8 +21,8 @@ struct CountCopyAndMove {
   static int Destructions;
   int val;
 
-  CountCopyAndMove() { ++Constructions; }
-  explicit CountCopyAndMove(int val) : val(val) { ++Constructions; }
+  CountCopyAndMove() { ++DefaultConstructions; }
+  explicit CountCopyAndMove(int val) : val(val) { ++ValueConstructions; }
   CountCopyAndMove(const CountCopyAndMove &other) : val(other.val) {
     ++CopyConstructions;
   }
@@ -41,7 +42,8 @@ struct CountCopyAndMove {
   ~CountCopyAndMove() { ++Destructions; }
 
   static void ResetCounts() {
-    Constructions = 0;
+    DefaultConstructions = 0;
+    ValueConstructions = 0;
     CopyConstructions = 0;
     CopyAssignments = 0;
     MoveConstructions = 0;
@@ -50,7 +52,7 @@ struct CountCopyAndMove {
   }
 
   static int TotalConstructions() {
-    return Constructions + MoveConstructions + CopyConstructions;
+    return DefaultConstructions + ValueConstructions + MoveConstructions + CopyConstructions;
   }
 
   static int TotalCopies() { return CopyConstructions + CopyAssignments; }



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