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LibJS: Segregate GC-allocated objects by type

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This patch adds two macros to declare per-type allocators:

- JS_DECLARE_ALLOCATOR(TypeName)
- JS_DEFINE_ALLOCATOR(TypeName)

When used, they add a type-specific CellAllocator that the Heap will
delegate allocation requests to.

The result of this is that GC objects of the same type always end up
within the same HeapBlock, drastically reducing the ability to perform
type confusion attacks.

It also improves HeapBlock utilization, since each block now has cells
sized exactly to the type used within that block. (Previously we only
had a handful of block sizes available, and most GC allocations ended
up with a large amount of slack in their tails.)

There is a small performance hit from this, but I'm sure we can make
up for it elsewhere.

Note that the old size-based allocators still exist, and we fall back
to them for any type that doesn't have its own CellAllocator.
This commit is contained in:
Andreas Kling 2023-11-19 09:45:05 +01:00
parent 84a8ee01e1
commit 3c74dc9f4d
428 changed files with 723 additions and 22 deletions
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14
Userland/Libraries/LibJS/Runtime/PromiseResolvingElementFunctions.h
View file

@ -14,6 +14,7 @@ namespace JS {
struct RemainingElements final : public Cell {
JS_CELL(RemainingElements, Cell);
JS_DECLARE_ALLOCATOR(RemainingElements);
u64 value { 0 };
@ -28,6 +29,7 @@ private:
class PromiseValueList final : public Cell {
JS_CELL(PromiseValueList, Cell);
JS_DECLARE_ALLOCATOR(PromiseValueList);
public:
Vector<Value>& values() { return m_values; }
@ -42,7 +44,8 @@ private:
};
class PromiseResolvingElementFunction : public NativeFunction {
JS_OBJECT(PromiseResolvingFunction, NativeFunction);
JS_OBJECT(PromiseResolvingElementFunction, NativeFunction);
JS_DECLARE_ALLOCATOR(PromiseResolvingElementFunction);
public:
virtual void initialize(Realm&) override;
@ -68,7 +71,8 @@ private:
// 27.2.4.1.3 Promise.all Resolve Element Functions, https://tc39.es/ecma262/#sec-promise.all-resolve-element-functions
class PromiseAllResolveElementFunction final : public PromiseResolvingElementFunction {
JS_OBJECT(PromiseResolvingFunction, NativeFunction);
JS_OBJECT(PromiseAllResolveElementFunction, NativeFunction);
JS_DECLARE_ALLOCATOR(PromiseAllResolveElementFunction);
public:
static NonnullGCPtr<PromiseAllResolveElementFunction> create(Realm&, size_t, PromiseValueList&, NonnullGCPtr<PromiseCapability const>, RemainingElements&);
@ -98,7 +102,8 @@ private:
// 27.2.4.2.3 Promise.allSettled Reject Element Functions, https://tc39.es/ecma262/#sec-promise.allsettled-reject-element-functions
class PromiseAllSettledRejectElementFunction final : public PromiseResolvingElementFunction {
JS_OBJECT(PromiseResolvingFunction, PromiseResolvingElementFunction);
JS_OBJECT(PromiseAllSettledRejectElementFunction, PromiseResolvingElementFunction);
JS_DECLARE_ALLOCATOR(PromiseAllSettledRejectElementFunction);
public:
static NonnullGCPtr<PromiseAllSettledRejectElementFunction> create(Realm&, size_t, PromiseValueList&, NonnullGCPtr<PromiseCapability const>, RemainingElements&);
@ -113,7 +118,8 @@ private:
// 27.2.4.3.2 Promise.any Reject Element Functions, https://tc39.es/ecma262/#sec-promise.any-reject-element-functions
class PromiseAnyRejectElementFunction final : public PromiseResolvingElementFunction {
JS_OBJECT(PromiseResolvingFunction, PromiseResolvingElementFunction);
JS_OBJECT(PromiseAnyRejectElementFunction, PromiseResolvingElementFunction);
JS_DECLARE_ALLOCATOR(PromiseAnyRejectElementFunction);
public:
static NonnullGCPtr<PromiseAnyRejectElementFunction> create(Realm&, size_t, PromiseValueList&, NonnullGCPtr<PromiseCapability const>, RemainingElements&);