[wasm] Fix stack-switching JS limit offset

Add the missing KB multiplier. Also add a flag to set the fixed stack
size.

R=clemensb@chromium.org

Bug: v8:12191
Change-Id: I9782192d2eef1986286f726a05444a4bec49fc66
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3875902Reviewed-by: Clemens Backes <clemensb@chromium.org>
Commit-Queue: Thibaud Michaud <thibaudm@chromium.org>
Cr-Commit-Position: refs/heads/main@{#83065}

src/flags/flag-definitions.h

@@ -1026,6 +1026,8 @@ DEFINE_DEBUG_BOOL(trace_wasm_streaming, false,
                   "trace streaming compilation of wasm code")
 DEFINE_DEBUG_BOOL(trace_wasm_stack_switching, false,
                   "trace wasm stack switching")
+DEFINE_INT(wasm_stack_switching_stack_size, V8_DEFAULT_STACK_SIZE_KB,
+           "default size of stacks for wasm stack-switching (in kB)")
 DEFINE_BOOL(liftoff, true,
             "enable Liftoff, the baseline compiler for WebAssembly")
 DEFINE_BOOL(liftoff_only, false,

src/wasm/stacks.cc

@@ -37,7 +37,7 @@ StackMemory::StackMemory(Isolate* isolate) : isolate_(isolate), owned_(true) {
   static std::atomic<int> next_id(1);
   id_ = next_id.fetch_add(1);
   PageAllocator* allocator = GetPlatformPageAllocator();
-  int kJsStackSizeKB = 4;
+  int kJsStackSizeKB = v8_flags.wasm_stack_switching_stack_size;
   size_ = (kJsStackSizeKB + kJSLimitOffsetKB) * KB;
   size_ = RoundUp(size_, allocator->AllocatePageSize());
   limit_ = static_cast<byte*>(

src/wasm/stacks.h

@@ -38,7 +38,7 @@ class StackMemory {
   static StackMemory* GetCurrentStackView(Isolate* isolate);
 
   ~StackMemory();
-  void* jslimit() const { return limit_ + kJSLimitOffsetKB; }
+  void* jslimit() const { return limit_ + kJSLimitOffsetKB * KB; }
   Address base() const { return reinterpret_cast<Address>(limit_ + size_); }
   JumpBuffer* jmpbuf() { return &jmpbuf_; }
   int id() { return id_; }

test/mjsunit/wasm/stack-switching.js

@@ -4,6 +4,10 @@
 
 // Flags: --allow-natives-syntax --experimental-wasm-stack-switching
 // Flags: --experimental-wasm-type-reflection --expose-gc
+// Flags: --wasm-stack-switching-stack-size=100
+
+// We pick a small stack size to run the stack overflow test quickly, but big
+// enough to run all the tests.
 
 load("test/mjsunit/wasm/wasm-module-builder.js");
 
@@ -478,3 +482,16 @@ function TestNestedSuspenders(suspend) {
   assertEquals([], export_sig.parameters);
   assertEquals(['externref'], export_sig.results);
 })();
+
+(function TestStackOverflow() {
+  print(arguments.callee.name);
+  let builder = new WasmModuleBuilder();
+  builder.addFunction("test", kSig_i_r)
+      .addBody([
+          kExprLocalGet, 0,
+          kExprCallFunction, 0
+          ]).exportFunc();
+  let instance = builder.instantiate();
+  let wrapper = ToPromising(instance.exports.test);
+  assertThrows(wrapper, RangeError, /Maximum call stack size exceeded/);
+})();