https://github.com/optimisan created
https://github.com/llvm/llvm-project/pull/121425
Recycler uses reinterpret_cast to an internal structure of size 8.
Invalid write occurs if Recycler is used for objects with sizes less
than 8.
>From 600fd4cd14dad8a2355d399fd4b67a8092d9637b Mon Sep 17 00:00:00 2001
From: Akshat Oke <akshat....@amd.com>
Date: Wed, 1 Jan 2025 06:33:26 +0000
Subject: [PATCH] [Support] Recycler: Enforce minimum allocation size
Recycler uses reinterpret_cast to an internal structure of size 8.
Invalid write occurs if Recycler is used for objects with sizes less
than 8.
---
llvm/include/llvm/Support/Recycler.h | 1 +
llvm/unittests/Support/CMakeLists.txt | 1 +
llvm/unittests/Support/RecyclerTest.cpp | 46 +++++++++++++++++++++++++
3 files changed, 48 insertions(+)
create mode 100644 llvm/unittests/Support/RecyclerTest.cpp
diff --git a/llvm/include/llvm/Support/Recycler.h
b/llvm/include/llvm/Support/Recycler.h
index bbd9ae321ae30c..2bf30b0b3d5247 100644
--- a/llvm/include/llvm/Support/Recycler.h
+++ b/llvm/include/llvm/Support/Recycler.h
@@ -85,6 +85,7 @@ class Recycler {
"Recycler allocation alignment is less than object align!");
static_assert(sizeof(SubClass) <= Size,
"Recycler allocation size is less than object size!");
+ static_assert(Size >= 8 && "Recycler size must be atleast 8");
return FreeList ? reinterpret_cast<SubClass *>(pop_val())
: static_cast<SubClass *>(Allocator.Allocate(Size, Align));
}
diff --git a/llvm/unittests/Support/CMakeLists.txt
b/llvm/unittests/Support/CMakeLists.txt
index d64f89847aa8e7..6de81658264420 100644
--- a/llvm/unittests/Support/CMakeLists.txt
+++ b/llvm/unittests/Support/CMakeLists.txt
@@ -69,6 +69,7 @@ add_llvm_unittest(SupportTests
PerThreadBumpPtrAllocatorTest.cpp
ProcessTest.cpp
ProgramTest.cpp
+ RecyclerTest.cpp
RegexTest.cpp
ReverseIterationTest.cpp
ReplaceFileTest.cpp
diff --git a/llvm/unittests/Support/RecyclerTest.cpp
b/llvm/unittests/Support/RecyclerTest.cpp
new file mode 100644
index 00000000000000..8cd763c0b83f8a
--- /dev/null
+++ b/llvm/unittests/Support/RecyclerTest.cpp
@@ -0,0 +1,46 @@
+//===--- unittest/Support/RecyclerTest.cpp
--------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM
Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Support/Recycler.h"
+#include "llvm/Support/AllocatorBase.h"
+#include "gtest/gtest.h"
+
+using namespace llvm;
+
+namespace {
+
+struct Object1 {
+ char Data[1];
+};
+
+class DecoratedMallocAllocator : public MallocAllocator {
+public:
+ int DeallocCount = 0;
+
+ template <typename T> void Deallocate(T *Ptr) {
+ DeallocCount++;
+ MallocAllocator::Deallocate(Ptr);
+ }
+};
+
+TEST(RecyclerTest, RecycleAllocation) {
+ DecoratedMallocAllocator Allocator;
+ // Recycler needs size to be atleast 8 bytes.
+ Recycler<Object1, 8, 8> R;
+ Object1 *A1 = R.Allocate(Allocator);
+ Object1 *A2 = R.Allocate(Allocator);
+ R.Deallocate(Allocator, A2);
+ Object1 *A3 = R.Allocate(Allocator);
+ EXPECT_EQ(A2, A3); // reuse the deallocated object.
+ R.Deallocate(Allocator, A1);
+ R.Deallocate(Allocator, A3);
+ R.clear(Allocator); // Should deallocate A1 and A3.
+ EXPECT_EQ(Allocator.DeallocCount, 2);
+}
+
+} // end anonymous namespace
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