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deps: V8: backport bef0d9c1bc90 · nodejs/node@8b37af8 · GitHub

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Commit 8b37af8

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joyeecheung
authored and
aduh95
committed
deps: V8: backport bef0d9c1bc90
Original commit message: [api] Add V8::GetWasmMemoryReservationSizeInBytes() When the system does not have enough virtual memory for the wasm cage, installing the trap handler would cause any code allocating wasm memory to throw. Therefore it's useful for the embedder to know when the system doesn't have enough virtual address space to allocate enough wasm cages and in that case, skip the trap handler installation so that wasm code can at least work (even not at the maximal performance). Node.js previously has a command line option --disable-wasm-trap-handler to fully disable trap-based bound checks, this new API would allow it to adapt automatically while keeping the optimization in the happy path, since it's not always possible for end users to opt-into disabling trap-based bound checks (for example, when a VS Code Server is loaded in a remote server for debugging). Refs: #62132 Refs: microsoft/vscode#251777 Change-Id: I345c076af2b2b47700e5716b49c3133fdf8a0981 Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/7638233 Reviewed-by: Jakob Kummerow <jkummerow@chromium.org> Reviewed-by: Michael Lippautz <mlippautz@chromium.org> Commit-Queue: Joyee Cheung <joyee@igalia.com> Reviewed-by: Clemens Backes <clemensb@chromium.org> Cr-Commit-Position: refs/heads/main@{#105702} Refs: v8/v8@bef0d9c Co-authored-by: Joyee Cheung <joyeec9h3@gmail.com> PR-URL: #62132 Backport-PR-URL: #64338 Refs: microsoft/vscode#251777 Refs: https://chromium-review.googlesource.com/c/v8/v8/+/7638233 Signed-off-by: Joyee Cheung <joyeec9h3@gmail.com> Reviewed-By: Richard Lau <richard.lau@ibm.com>
1 parent 6e2f7e6 commit 8b37af8

5 files changed

Lines changed: 93 additions & 20 deletions

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‎deps/v8/include/v8-initialization.h‎

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Original file line numberDiff line numberDiff line change
@@ -253,6 +253,35 @@ class V8_EXPORT V8 {
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static size_t GetSandboxReservationSizeInBytes();
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#endif // V8_ENABLE_SANDBOX
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256+
enum class WasmMemoryType {
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kMemory32,
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kMemory64,
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};
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/**
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* Returns the virtual address space reservation size (in bytes) needed
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* for one WebAssembly memory instance of the given capacity.
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*
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* \param type Whether this is a memory32 or memory64 instance.
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* \param byte_capacity The maximum size, in bytes, of the WebAssembly
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* memory. Values exceeding the engine's maximum allocatable memory
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* size for the given type (determined by max_mem32_pages or
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* max_mem64_pages) are clamped.
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*
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* When trap-based bounds checking is enabled by
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* EnableWebAssemblyTrapHandler(), the amount of virtual address space
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* that V8 needs to reserve for each WebAssembly memory instance can
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* be much bigger than the requested size. If the process does
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* not have enough virtual memory available, WebAssembly memory allocation
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* would fail. During the initialization of V8, embedders can use this method
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* to estimate whether the process has enough virtual memory for their
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* usage of WebAssembly, and decide whether to enable the trap handler
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* via EnableWebAssemblyTrapHandler(), or to skip it and reduce the amount of
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* virtual memory required to keep the application running.
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*/
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static size_t GetWasmMemoryReservationSizeInBytes(WasmMemoryType type,
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size_t byte_capacity);
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/**
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* Activate trap-based bounds checking for WebAssembly.
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*

‎deps/v8/src/api/api.cc‎

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Original file line numberDiff line numberDiff line change
@@ -148,6 +148,7 @@
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#include "src/wasm/value-type.h"
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#include "src/wasm/wasm-engine.h"
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#include "src/wasm/wasm-js.h"
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#include "src/wasm/wasm-limits.h"
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#include "src/wasm/wasm-objects-inl.h"
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#include "src/wasm/wasm-result.h"
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#include "src/wasm/wasm-serialization.h"
@@ -6504,6 +6505,26 @@ bool TryHandleWebAssemblyTrapWindows(EXCEPTION_POINTERS* exception) {
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}
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#endif
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size_t V8::GetWasmMemoryReservationSizeInBytes(WasmMemoryType type,
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size_t byte_capacity) {
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#if V8_ENABLE_WEBASSEMBLY
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bool is_memory64 = type == WasmMemoryType::kMemory64;
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uint64_t max_byte_capacity =
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is_memory64 ? i::wasm::max_mem64_bytes() : i::wasm::max_mem32_bytes();
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if (byte_capacity > max_byte_capacity) {
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byte_capacity = static_cast<size_t>(max_byte_capacity);
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}
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#if V8_TRAP_HANDLER_SUPPORTED
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if (!is_memory64 || i::v8_flags.wasm_memory64_trap_handling) {
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return i::BackingStore::GetWasmReservationSize(
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/* has_guard_regions */ true, byte_capacity,
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/* is_wasm_memory64 */ is_memory64);
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}
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#endif // V8_TRAP_HANDLER_SUPPORTED
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#endif // V8_ENABLE_WEBASSEMBLY
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return byte_capacity;
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}
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bool V8::EnableWebAssemblyTrapHandler(bool use_v8_signal_handler) {
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#if V8_ENABLE_WEBASSEMBLY
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return v8::internal::trap_handler::EnableTrapHandler(use_v8_signal_handler);

‎deps/v8/src/objects/backing-store.cc‎

Lines changed: 22 additions & 20 deletions
Original file line numberDiff line numberDiff line change
@@ -51,8 +51,25 @@ enum class AllocationStatus {
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kOtherFailure // Failed for an unknown reason
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};
5353

54-
size_t GetReservationSize(bool has_guard_regions, size_t byte_capacity,
55-
bool is_wasm_memory64) {
54+
base::AddressRegion GetReservedRegion(bool has_guard_regions,
55+
bool is_wasm_memory64, void* buffer_start,
56+
size_t byte_capacity) {
57+
return base::AddressRegion(
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reinterpret_cast<Address>(buffer_start),
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BackingStore::GetWasmReservationSize(has_guard_regions, byte_capacity,
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is_wasm_memory64));
61+
}
62+
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void RecordStatus(Isolate* isolate, AllocationStatus status) {
64+
isolate->counters()->wasm_memory_allocation_result()->AddSample(
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static_cast<int>(status));
66+
}
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68+
} // namespace
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size_t BackingStore::GetWasmReservationSize(bool has_guard_regions,
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size_t byte_capacity,
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bool is_wasm_memory64) {
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#if V8_TARGET_ARCH_64_BIT && V8_ENABLE_WEBASSEMBLY
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DCHECK_IMPLIES(is_wasm_memory64 && has_guard_regions,
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v8_flags.wasm_memory64_trap_handling);
@@ -73,21 +90,6 @@ size_t GetReservationSize(bool has_guard_regions, size_t byte_capacity,
7390
return byte_capacity;
7491
}
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76-
base::AddressRegion GetReservedRegion(bool has_guard_regions,
77-
bool is_wasm_memory64, void* buffer_start,
78-
size_t byte_capacity) {
79-
return base::AddressRegion(
80-
reinterpret_cast<Address>(buffer_start),
81-
GetReservationSize(has_guard_regions, byte_capacity, is_wasm_memory64));
82-
}
83-
84-
void RecordStatus(Isolate* isolate, AllocationStatus status) {
85-
isolate->counters()->wasm_memory_allocation_result()->AddSample(
86-
static_cast<int>(status));
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}
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89-
} // namespace
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// The backing store for a Wasm shared memory remembers all the isolates
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// with which it has been shared.
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struct SharedWasmMemoryData {
@@ -161,7 +163,7 @@ BackingStore::~BackingStore() {
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162164
#if V8_ENABLE_WEBASSEMBLY
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if (is_wasm_memory()) {
164-
size_t reservation_size = GetReservationSize(
166+
size_t reservation_size = GetWasmReservationSize(
165167
has_guard_regions(), byte_capacity_, is_wasm_memory64());
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TRACE_BS(
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"BSw:free bs=%p mem=%p (length=%zu, capacity=%zu, reservation=%zu)\n",
@@ -315,8 +317,8 @@ std::unique_ptr<BackingStore> BackingStore::TryAllocateAndPartiallyCommitMemory(
315317
};
316318

317319
size_t byte_capacity = maximum_pages * page_size;
318-
size_t reservation_size =
319-
GetReservationSize(has_guard_regions, byte_capacity, is_wasm_memory64);
320+
size_t reservation_size = GetWasmReservationSize(
321+
has_guard_regions, byte_capacity, is_wasm_memory64);
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//--------------------------------------------------------------------------
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// Allocate pages (inaccessible by default).

‎deps/v8/src/objects/backing-store.h‎

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Original file line numberDiff line numberDiff line change
@@ -183,6 +183,11 @@ class V8_EXPORT_PRIVATE BackingStore : public BackingStoreBase {
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184184
uint32_t id() const { return id_; }
185185

186+
// Return the size of the reservation needed for a wasm backing store.
187+
static size_t GetWasmReservationSize(bool has_guard_regions,
188+
size_t byte_capacity,
189+
bool is_wasm_memory64);
190+
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private:
187192
friend class GlobalBackingStoreRegistry;
188193

‎deps/v8/test/unittests/api/api-wasm-unittest.cc‎

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Original file line numberDiff line numberDiff line change
@@ -122,6 +122,22 @@ void WasmStreamingMoreFunctionsCanBeSerializedCallback(
122122
streaming->SetMoreFunctionsCanBeSerializedCallback([](CompiledWasmModule) {});
123123
}
124124

125+
TEST_F(ApiWasmTest, GetWasmMemoryReservationSizeInBytes) {
126+
constexpr size_t kCapacity = 64 * 1024; // 64 KiB
127+
size_t reservation = V8::GetWasmMemoryReservationSizeInBytes(
128+
V8::WasmMemoryType::kMemory32, kCapacity);
129+
size_t reservation64 = V8::GetWasmMemoryReservationSizeInBytes(
130+
V8::WasmMemoryType::kMemory64, kCapacity);
131+
132+
#if V8_TRAP_HANDLER_SUPPORTED
133+
EXPECT_GE(reservation, kCapacity);
134+
EXPECT_GE(reservation64, kCapacity);
135+
#else
136+
EXPECT_EQ(reservation, kCapacity);
137+
EXPECT_EQ(reservation64, kCapacity);
138+
#endif // V8_TRAP_HANDLER_SUPPORTED
139+
}
140+
125141
TEST_F(ApiWasmTest, WasmStreamingCallback) {
126142
TestWasmStreaming(WasmStreamingCallbackTestCallbackIsCalled,
127143
Promise::kPending);

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