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Commit fb85d38

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joyeecheungtargos
joyeecheung
authored and
targos
committed
cli: allow running wasm in limited vmem with --disable-wasm-trap-handler
By default, Node.js enables trap-handler-based WebAssembly bound checks. As a result, V8 does not need to insert inline bound checks int the code compiled from WebAssembly which may speedup WebAssembly execution significantly, but this optimization requires allocating a big virtual memory cage (currently 10GB). If the Node.js process does not have access to a large enough virtual memory address space due to system configurations or hardware limitations, users won't be able to run any WebAssembly that involves allocation in this virtual memory cage and will see an out-of-memory error. ```console $ ulimit -v 5000000 $ node -p "new WebAssembly.Memory({ initial: 10, maximum: 100 });" [eval]:1 new WebAssembly.Memory({ initial: 10, maximum: 100 }); ^ RangeError: WebAssembly.Memory(): could not allocate memory at [eval]:1:1 at runScriptInThisContext (node:internal/vm:209:10) at node:internal/process/execution:118:14 at [eval]-wrapper:6:24 at runScript (node:internal/process/execution:101:62) at evalScript (node:internal/process/execution:136:3) at node:internal/main/eval_string:49:3 ``` `--disable-wasm-trap-handler` disables this optimization so that users can at least run WebAssembly (with a less optimial performance) when the virtual memory address space available to their Node.js process is lower than what the V8 WebAssembly memory cage needs. PR-URL: #52766 Reviewed-By: Rafael Gonzaga <rafael.nunu@hotmail.com>
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‎doc/api/cli.md‎

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+40Lines changed: 40 additions & 0 deletions
  • Display the source diff
  • Display the rich diff
Original file line numberDiff line numberDiff line change
@@ -565,6 +565,45 @@ const vm = require('node:vm');
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vm.measureMemory();
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```
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### `--disable-wasm-trap-handler`
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<!-- YAML
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added: REPLACEME
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-->
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By default, Node.js enables trap-handler-based WebAssembly bound
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checks. As a result, V8 does not need to insert inline bound checks
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int the code compiled from WebAssembly which may speedup WebAssembly
577+
execution significantly, but this optimization requires allocating
578+
a big virtual memory cage (currently 10GB). If the Node.js process
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does not have access to a large enough virtual memory address space
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due to system configurations or hardware limitations, users won't
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be able to run any WebAssembly that involves allocation in this
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virtual memory cage and will see an out-of-memory error.
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```console
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$ ulimit -v 5000000
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$ node -p "new WebAssembly.Memory({ initial: 10, maximum: 100 });"
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[eval]:1
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new WebAssembly.Memory({ initial: 10, maximum: 100 });
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^
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RangeError: WebAssembly.Memory(): could not allocate memory
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at [eval]:1:1
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at runScriptInThisContext (node:internal/vm:209:10)
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at node:internal/process/execution:118:14
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at [eval]-wrapper:6:24
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at runScript (node:internal/process/execution:101:62)
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at evalScript (node:internal/process/execution:136:3)
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at node:internal/main/eval_string:49:3
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```
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`--disable-wasm-trap-handler` disables this optimization so that
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users can at least run WebAssembly (with less optimal performance)
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when the virtual memory address space available to their Node.js
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process is lower than what the V8 WebAssembly memory cage needs.
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### `--disable-proto=mode`
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<!-- YAML
@@ -2634,6 +2673,7 @@ one is included in the list below.
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* `--diagnostic-dir`
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* `--disable-proto`
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* `--disable-warning`
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* `--disable-wasm-trap-handler`
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* `--dns-result-order`
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* `--enable-fips`
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* `--enable-network-family-autoselection`
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‎doc/node.1‎

Copy file name to clipboardExpand all lines: doc/node.1
+5Lines changed: 5 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -142,6 +142,11 @@ is `delete`, the property will be removed entirely. If
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is `throw`, accesses to the property will throw an exception with the code
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`ERR_PROTO_ACCESS`.
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.
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.It Fl -disable-wasm-trap-handler Ns = Ns Ar mode
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Disable trap-handler-based WebAssembly bound checks and fall back to
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inline bound checks so that WebAssembly can be run with limited virtual
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memory.
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.
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.It Fl -disallow-code-generation-from-strings
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Make built-in language features like `eval` and `new Function` that generate
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code from strings throw an exception instead. This does not affect the Node.js
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‎src/node.cc‎

Copy file name to clipboardExpand all lines: src/node.cc
+38-31Lines changed: 38 additions & 31 deletions
Original file line numberDiff line numberDiff line change
@@ -425,6 +425,7 @@ MaybeLocal<Value> StartExecution(Environment* env, StartExecutionCallback cb) {
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typedef void (*sigaction_cb)(int signo, siginfo_t* info, void* ucontext);
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#endif
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#if NODE_USE_V8_WASM_TRAP_HANDLER
428+
static std::atomic<bool> is_wasm_trap_handler_configured{false};
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#if defined(_WIN32)
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static LONG WINAPI TrapWebAssemblyOrContinue(EXCEPTION_POINTERS* exception) {
430431
if (v8::TryHandleWebAssemblyTrapWindows(exception)) {
@@ -470,15 +471,17 @@ void RegisterSignalHandler(int signal,
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bool reset_handler) {
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CHECK_NOT_NULL(handler);
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#if NODE_USE_V8_WASM_TRAP_HANDLER
473-
if (signal == SIGSEGV) {
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// Stash the user-registered handlers for TrapWebAssemblyOrContinue
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// to call out to when the signal is not coming from a WASM OOM.
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if (signal == SIGSEGV && is_wasm_trap_handler_configured.load()) {
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CHECK(previous_sigsegv_action.is_lock_free());
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CHECK(!reset_handler);
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previous_sigsegv_action.store(handler);
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return;
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}
479-
// TODO(align behavior between macos and other in next major version)
482+
// TODO(align behavior between macos and other in next major version)
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#if defined(__APPLE__)
481-
if (signal == SIGBUS) {
484+
if (signal == SIGBUS && is_wasm_trap_handler_configured.load()) {
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CHECK(previous_sigbus_action.is_lock_free());
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CHECK(!reset_handler);
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previous_sigbus_action.store(handler);
@@ -630,25 +633,6 @@ static void PlatformInit(ProcessInitializationFlags::Flags flags) {
630633
if (!(flags & ProcessInitializationFlags::kNoDefaultSignalHandling)) {
631634
RegisterSignalHandler(SIGINT, SignalExit, true);
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RegisterSignalHandler(SIGTERM, SignalExit, true);
633-
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#if NODE_USE_V8_WASM_TRAP_HANDLER
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// Tell V8 to disable emitting WebAssembly
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// memory bounds checks. This means that we have
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// to catch the SIGSEGV/SIGBUS in TrapWebAssemblyOrContinue
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// and pass the signal context to V8.
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{
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struct sigaction sa;
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memset(&sa, 0, sizeof(sa));
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sa.sa_sigaction = TrapWebAssemblyOrContinue;
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sa.sa_flags = SA_SIGINFO;
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CHECK_EQ(sigaction(SIGSEGV, &sa, nullptr), 0);
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// TODO(align behavior between macos and other in next major version)
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#if defined(__APPLE__)
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CHECK_EQ(sigaction(SIGBUS, &sa, nullptr), 0);
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#endif
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}
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V8::EnableWebAssemblyTrapHandler(false);
651-
#endif // NODE_USE_V8_WASM_TRAP_HANDLER
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}
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if (!(flags & ProcessInitializationFlags::kNoAdjustResourceLimits)) {
@@ -675,14 +659,6 @@ static void PlatformInit(ProcessInitializationFlags::Flags flags) {
675659
}
676660
#endif // __POSIX__
677661
#ifdef _WIN32
678-
#ifdef NODE_USE_V8_WASM_TRAP_HANDLER
679-
{
680-
constexpr ULONG first = TRUE;
681-
per_process::old_vectored_exception_handler =
682-
AddVectoredExceptionHandler(first, TrapWebAssemblyOrContinue);
683-
}
684-
V8::EnableWebAssemblyTrapHandler(false);
685-
#endif // NODE_USE_V8_WASM_TRAP_HANDLER
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if (!(flags & ProcessInitializationFlags::kNoStdioInitialization)) {
687663
for (int fd = 0; fd <= 2; ++fd) {
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auto handle = reinterpret_cast<HANDLE>(_get_osfhandle(fd));
@@ -1225,6 +1201,37 @@ InitializeOncePerProcessInternal(const std::vector<std::string>& args,
12251201
cppgc::InitializeProcess(allocator);
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}
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#if NODE_USE_V8_WASM_TRAP_HANDLER
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bool use_wasm_trap_handler =
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!per_process::cli_options->disable_wasm_trap_handler;
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if (!(flags & ProcessInitializationFlags::kNoDefaultSignalHandling) &&
1208+
use_wasm_trap_handler) {
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#if defined(_WIN32)
1210+
constexpr ULONG first = TRUE;
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per_process::old_vectored_exception_handler =
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AddVectoredExceptionHandler(first, TrapWebAssemblyOrContinue);
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#else
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// Tell V8 to disable emitting WebAssembly
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// memory bounds checks. This means that we have
1216+
// to catch the SIGSEGV/SIGBUS in TrapWebAssemblyOrContinue
1217+
// and pass the signal context to V8.
1218+
{
1219+
struct sigaction sa;
1220+
memset(&sa, 0, sizeof(sa));
1221+
sa.sa_sigaction = TrapWebAssemblyOrContinue;
1222+
sa.sa_flags = SA_SIGINFO;
1223+
CHECK_EQ(sigaction(SIGSEGV, &sa, nullptr), 0);
1224+
// TODO(align behavior between macos and other in next major version)
1225+
#if defined(__APPLE__)
1226+
CHECK_EQ(sigaction(SIGBUS, &sa, nullptr), 0);
1227+
#endif
1228+
}
1229+
#endif // defined(_WIN32)
1230+
is_wasm_trap_handler_configured.store(true);
1231+
V8::EnableWebAssemblyTrapHandler(false);
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}
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#endif // NODE_USE_V8_WASM_TRAP_HANDLER
1234+
12281235
performance::performance_v8_start = PERFORMANCE_NOW();
12291236
per_process::v8_initialized = true;
12301237

@@ -1254,7 +1261,7 @@ void TearDownOncePerProcess() {
12541261
}
12551262

12561263
#if NODE_USE_V8_WASM_TRAP_HANDLER && defined(_WIN32)
1257-
if (!(flags & ProcessInitializationFlags::kNoDefaultSignalHandling)) {
1264+
if (is_wasm_trap_handler_configured.load()) {
12581265
RemoveVectoredExceptionHandler(per_process::old_vectored_exception_handler);
12591266
}
12601267
#endif
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‎src/node_options.cc‎

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+7Lines changed: 7 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -1066,6 +1066,13 @@ PerProcessOptionsParser::PerProcessOptionsParser(
10661066
AddOption("--run",
10671067
"Run a script specified in package.json",
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&PerProcessOptions::run);
1069+
AddOption(
1070+
"--disable-wasm-trap-handler",
1071+
"Disable trap-handler-based WebAssembly bound checks. V8 will insert "
1072+
"inline bound checks when compiling WebAssembly which may slow down "
1073+
"performance.",
1074+
&PerProcessOptions::disable_wasm_trap_handler,
1075+
kAllowedInEnvvar);
10691076
}
10701077

10711078
inline std::string RemoveBrackets(const std::string& host) {
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‎src/node_options.h‎

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+2Lines changed: 2 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -306,6 +306,8 @@ class PerProcessOptions : public Options {
306306
bool openssl_shared_config = false;
307307
#endif
308308

309+
bool disable_wasm_trap_handler = false;
310+
309311
// Per-process because reports can be triggered outside a known V8 context.
310312
bool report_on_fatalerror = false;
311313
bool report_compact = false;
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‎test/testpy/__init__.py‎

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+12Lines changed: 12 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -167,3 +167,15 @@ def ListTests(self, current_path, path, arch, mode):
167167
for tst in result:
168168
tst.disable_core_files = True
169169
return result
170+
171+
class WasmAllocationTestConfiguration(SimpleTestConfiguration):
172+
def __init__(self, context, root, section, additional=None):
173+
super(WasmAllocationTestConfiguration, self).__init__(context, root, section,
174+
additional)
175+
176+
def ListTests(self, current_path, path, arch, mode):
177+
result = super(WasmAllocationTestConfiguration, self).ListTests(
178+
current_path, path, arch, mode)
179+
for tst in result:
180+
tst.max_virtual_memory = 5 * 1024 * 1024 * 1024 # 5GB
181+
return result
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‎test/wasm-allocation/test-wasm-allocation.js‎

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+7Lines changed: 7 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,7 @@
1+
// Flags: --disable-wasm-trap-handler
2+
// Test that with limited virtual memory space, --disable-wasm-trap-handler
3+
// allows WASM to at least run with inline bound checks.
4+
'use strict';
5+
6+
require('../common');
7+
new WebAssembly.Memory({ initial: 10, maximum: 100 });
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‎test/wasm-allocation/testcfg.py‎

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+6Lines changed: 6 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,6 @@
1+
import sys, os
2+
sys.path.append(os.path.join(os.path.dirname(__file__), '..'))
3+
import testpy
4+
5+
def GetConfiguration(context, root):
6+
return testpy.WasmAllocationTestConfiguration(context, root, 'wasm-allocation')
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‎test/wasm-allocation/wasm-allocation.status‎

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+10Lines changed: 10 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,10 @@
1+
prefix wasm-allocation
2+
3+
# To mark a test as flaky, list the test name in the appropriate section
4+
# below, without ".js", followed by ": PASS,FLAKY". Example:
5+
# sample-test : PASS,FLAKY
6+
7+
[true] # This section applies to all platforms
8+
9+
[$system!=linux || $asan==on]
10+
test-wasm-allocation: SKIP

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