jlebar created this revision.
jlebar added reviewers: compnerd, dblaikie.
jlebar added subscribers: llvm-commits, cfe-commits.
Herald added subscribers: mgorny, klimek.
This class is unnecessary.
Its comment indicated that it was a compile error to allocate an
instance of a class that inherits from RefCountedBaseVPTR on the stack.
This may have been true at one point, but it's not today.
Moreover you really do not want to allocate *any* refcounted object on
the stack, vptrs or not, so if we did have a way to prevent these
objects from being stack-allocated, we'd want to apply it to regular
RefCountedBase too, obviating the need for a separate RefCountedBaseVPTR
class.
It seems that the main way RefCountedBaseVPTR provides safety is by
making its subclass's destructor virtual. This may have been helpful at
one point, but these days clang will emit an error if you define a class
with virtual functions that inherits from RefCountedBase but doesn't
have a virtual destructor.
https://reviews.llvm.org/D28162
Files:
clang/include/clang/ASTMatchers/Dynamic/VariantValue.h
clang/include/clang/Basic/LLVM.h
clang/include/clang/StaticAnalyzer/Core/BugReporter/PathDiagnostic.h
llvm/include/llvm/ADT/IntrusiveRefCntPtr.h
llvm/lib/Support/CMakeLists.txt
llvm/lib/Support/IntrusiveRefCntPtr.cpp
llvm/unittests/ADT/IntrusiveRefCntPtrTest.cpp
Index: llvm/unittests/ADT/IntrusiveRefCntPtrTest.cpp
===================================================================
--- llvm/unittests/ADT/IntrusiveRefCntPtrTest.cpp
+++ llvm/unittests/ADT/IntrusiveRefCntPtrTest.cpp
@@ -11,19 +11,29 @@
#include "gtest/gtest.h"
namespace {
-struct VirtualRefCounted : public llvm::RefCountedBaseVPTR {
+struct VirtualRefCounted : public llvm::RefCountedBase<VirtualRefCounted> {
+ VirtualRefCounted() { ++NumInstances; }
+ VirtualRefCounted(const VirtualRefCounted &) { ++NumInstances; }
+ virtual ~VirtualRefCounted() { --NumInstances; }
virtual void f() {}
+
+ static int NumInstances;
};
-}
+
+int VirtualRefCounted::NumInstances = 0;
+} // anonymous namespace
namespace llvm {
-// Run this test with valgrind to detect memory leaks.
-TEST(IntrusiveRefCntPtr, RefCountedBaseVPTRCopyDoesNotLeak) {
- VirtualRefCounted *V1 = new VirtualRefCounted;
- IntrusiveRefCntPtr<VirtualRefCounted> R1 = V1;
- VirtualRefCounted *V2 = new VirtualRefCounted(*V1);
- IntrusiveRefCntPtr<VirtualRefCounted> R2 = V2;
+TEST(IntrusiveRefCntPtr, VirtualRefCountedCopyDoesNotLeak) {
+ {
+ VirtualRefCounted *V1 = new VirtualRefCounted;
+ IntrusiveRefCntPtr<VirtualRefCounted> R1 = V1;
+ VirtualRefCounted *V2 = new VirtualRefCounted(*V1);
+ IntrusiveRefCntPtr<VirtualRefCounted> R2 = V2;
+ EXPECT_EQ(2, VirtualRefCounted::NumInstances);
+ }
+ EXPECT_EQ(0, VirtualRefCounted::NumInstances);
}
struct SimpleRefCounted : public RefCountedBase<SimpleRefCounted> {};
Index: llvm/lib/Support/IntrusiveRefCntPtr.cpp
===================================================================
--- llvm/lib/Support/IntrusiveRefCntPtr.cpp
+++ /dev/null
@@ -1,14 +0,0 @@
-//== IntrusiveRefCntPtr.cpp - Smart Refcounting Pointer ----------*- C++ -*-==//
-//
-// The LLVM Compiler Infrastructure
-//
-// This file is distributed under the University of Illinois Open Source
-// License. See LICENSE.TXT for details.
-//
-//===----------------------------------------------------------------------===//
-
-#include "llvm/ADT/IntrusiveRefCntPtr.h"
-
-using namespace llvm;
-
-void RefCountedBaseVPTR::anchor() { }
Index: llvm/lib/Support/CMakeLists.txt
===================================================================
--- llvm/lib/Support/CMakeLists.txt
+++ llvm/lib/Support/CMakeLists.txt
@@ -61,7 +61,6 @@
Hashing.cpp
IntEqClasses.cpp
IntervalMap.cpp
- IntrusiveRefCntPtr.cpp
JamCRC.cpp
LEB128.cpp
LineIterator.cpp
Index: llvm/include/llvm/ADT/IntrusiveRefCntPtr.h
===================================================================
--- llvm/include/llvm/ADT/IntrusiveRefCntPtr.h
+++ llvm/include/llvm/ADT/IntrusiveRefCntPtr.h
@@ -9,9 +9,9 @@
//
// This file defines IntrusiveRefCntPtr, a template class that
// implements a "smart" pointer for objects that maintain their own
-// internal reference count, and RefCountedBase/RefCountedBaseVPTR, two
-// generic base classes for objects that wish to have their lifetimes
-// managed using reference counting.
+// internal reference count, and RefCountedBase, a generic base class
+// for objects that wish to have their lifetimes managed using reference
+// counting.
//
// IntrusiveRefCntPtr is similar to Boost's intrusive_ptr with added
// LLVM-style casting.
@@ -52,36 +52,6 @@
}
};
-//===----------------------------------------------------------------------===//
-/// RefCountedBaseVPTR - A class that has the same function as
-/// RefCountedBase, but with a virtual destructor. Should be used
-/// instead of RefCountedBase for classes that already have virtual
-/// methods to enforce dynamic allocation via 'new'. Classes that
-/// inherit from RefCountedBaseVPTR can't be allocated on stack -
-/// attempting to do this will produce a compile error.
-//===----------------------------------------------------------------------===//
- class RefCountedBaseVPTR {
- mutable unsigned ref_cnt = 0;
-
- virtual void anchor();
-
- protected:
- RefCountedBaseVPTR() = default;
- RefCountedBaseVPTR(const RefCountedBaseVPTR &) : ref_cnt(0) {}
-
- virtual ~RefCountedBaseVPTR() = default;
-
- void Retain() const { ++ref_cnt; }
- void Release() const {
- assert (ref_cnt > 0 && "Reference count is already zero.");
- if (--ref_cnt == 0) delete this;
- }
-
- template <typename T>
- friend struct IntrusiveRefCntPtrInfo;
- };
-
-
template <typename T> struct IntrusiveRefCntPtrInfo {
static void retain(T *obj) { obj->Retain(); }
static void release(T *obj) { obj->Release(); }
@@ -124,10 +94,9 @@
/// wrapping NULL pointers.
///
/// Reference counting is implemented via calls to
-/// Obj->Retain()/Obj->Release(). Release() is required to destroy
-/// the object when the reference count reaches zero. Inheriting from
-/// RefCountedBase/RefCountedBaseVPTR takes care of this
-/// automatically.
+/// Obj->Retain()/Obj->Release(). Release() is required to destroy the
+/// object when the reference count reaches zero. Inheriting from
+/// RefCountedBase takes care of this automatically.
//===----------------------------------------------------------------------===//
template <typename T>
class IntrusiveRefCntPtr {
Index: clang/include/clang/StaticAnalyzer/Core/BugReporter/PathDiagnostic.h
===================================================================
--- clang/include/clang/StaticAnalyzer/Core/BugReporter/PathDiagnostic.h
+++ clang/include/clang/StaticAnalyzer/Core/BugReporter/PathDiagnostic.h
@@ -334,7 +334,7 @@
// Path "pieces" for path-sensitive diagnostics.
//===----------------------------------------------------------------------===//
-class PathDiagnosticPiece : public RefCountedBaseVPTR {
+class PathDiagnosticPiece : public RefCountedBase<PathDiagnosticPiece> {
public:
enum Kind { ControlFlow, Event, Macro, Call, Note };
enum DisplayHint { Above, Below };
@@ -366,7 +366,7 @@
PathDiagnosticPiece(Kind k, DisplayHint hint = Below);
public:
- ~PathDiagnosticPiece() override;
+ virtual ~PathDiagnosticPiece();
StringRef getString() const { return str; }
Index: clang/include/clang/Basic/LLVM.h
===================================================================
--- clang/include/clang/Basic/LLVM.h
+++ clang/include/clang/Basic/LLVM.h
@@ -43,7 +43,6 @@
template <typename T> class IntrusiveRefCntPtr;
template <typename T> struct IntrusiveRefCntPtrInfo;
template <class Derived> class RefCountedBase;
- class RefCountedBaseVPTR;
class raw_ostream;
class raw_pwrite_stream;
@@ -76,7 +75,6 @@
using llvm::IntrusiveRefCntPtr;
using llvm::IntrusiveRefCntPtrInfo;
using llvm::RefCountedBase;
- using llvm::RefCountedBaseVPTR;
using llvm::raw_ostream;
using llvm::raw_pwrite_stream;
Index: clang/include/clang/ASTMatchers/Dynamic/VariantValue.h
===================================================================
--- clang/include/clang/ASTMatchers/Dynamic/VariantValue.h
+++ clang/include/clang/ASTMatchers/Dynamic/VariantValue.h
@@ -119,9 +119,9 @@
/// \brief Payload interface to be specialized by each matcher type.
///
/// It follows a similar interface as VariantMatcher itself.
- class Payload : public RefCountedBaseVPTR {
+ class Payload : public RefCountedBase<Payload> {
public:
- ~Payload() override;
+ virtual ~Payload();
virtual llvm::Optional<DynTypedMatcher> getSingleMatcher() const = 0;
virtual std::string getTypeAsString() const = 0;
virtual llvm::Optional<DynTypedMatcher>
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