Wrap executions of Rust code called from JS in catch_unwind. Propagate the interrupted panic to the origin of the JS execution via TLS before resuming. Fix #6462.

components/script/dom/bindings/codegen/CodegenRust.py

@@ -2145,7 +2145,7 @@ class CGAbstractMethod(CGThing):
     """
     def __init__(self, descriptor, name, returnType, args, inline=False,
                  alwaysInline=False, extern=False, pub=False, templateArgs=None,
-                 unsafe=False, docs=None):
+                 unsafe=False, docs=None, doesNotPanic=False):
         CGThing.__init__(self)
         self.descriptor = descriptor
         self.name = name
@@ -2157,6 +2157,7 @@ class CGAbstractMethod(CGThing):
         self.pub = pub
         self.unsafe = unsafe
         self.docs = docs
+        self.catchPanic = self.extern and not doesNotPanic
 
     def _argstring(self):
         return ', '.join([a.declare() for a in self.args])
@@ -2199,6 +2200,19 @@ class CGAbstractMethod(CGThing):
         if self.unsafe and not self.extern:
             body = CGWrapper(CGIndenter(body), pre="unsafe {\n", post="\n}")
 
+        if self.catchPanic:
+            body = CGWrapper(CGIndenter(body),
+                             pre="let result = panic::catch_unwind(AssertUnwindSafe(|| {\n",
+                             post=("""}));
+match result {
+    Ok(result) => result,
+    Err(error) => {
+        store_panic_result(error);
+        return%s;
+    }
+}
+""" % ("" if self.returnType == "void" else " false")))
+
         return CGWrapper(CGIndenter(body),
                          pre=self.definition_prologue(),
                          post=self.definition_epilogue()).define()
@@ -2447,9 +2461,9 @@ class CGAbstractExternMethod(CGAbstractMethod):
     Abstract base class for codegen of implementation-only (no
     declaration) static methods.
     """
-    def __init__(self, descriptor, name, returnType, args):
+    def __init__(self, descriptor, name, returnType, args, doesNotPanic=False):
         CGAbstractMethod.__init__(self, descriptor, name, returnType, args,
-                                  inline=False, extern=True)
+                                  inline=False, extern=True, doesNotPanic=doesNotPanic)
 
 
 class PropertyArrays():
@@ -4830,7 +4844,7 @@ return true;""" % (getIndexedOrExpando, getNamed)
 class CGDOMJSProxyHandler_className(CGAbstractExternMethod):
     def __init__(self, descriptor):
         args = [Argument('*mut JSContext', 'cx'), Argument('HandleObject', '_proxy')]
-        CGAbstractExternMethod.__init__(self, descriptor, "className", "*const i8", args)
+        CGAbstractExternMethod.__init__(self, descriptor, "className", "*const i8", args, doesNotPanic=True)
         self.descriptor = descriptor
 
     def getBody(self):
@@ -4845,7 +4859,7 @@ class CGAbstractClassHook(CGAbstractExternMethod):
     Meant for implementing JSClass hooks, like Finalize or Trace. Does very raw
     'this' unwrapping as it assumes that the unwrapped type is always known.
     """
-    def __init__(self, descriptor, name, returnType, args):
+    def __init__(self, descriptor, name, returnType, args, doesNotPanic=False):
         CGAbstractExternMethod.__init__(self, descriptor, name, returnType,
                                         args)
 
@@ -4905,7 +4919,7 @@ class CGClassTraceHook(CGAbstractClassHook):
     def __init__(self, descriptor):
         args = [Argument('*mut JSTracer', 'trc'), Argument('*mut JSObject', 'obj')]
         CGAbstractClassHook.__init__(self, descriptor, TRACE_HOOK_NAME, 'void',
-                                     args)
+                                     args, doesNotPanic=True)
         self.traceGlobal = descriptor.isGlobal()
 
     def generate_code(self):
@@ -5597,11 +5611,13 @@ class CGBindingRoot(CGThing):
             'mem::heap_size_of_raw_self_and_children',
             'libc',
             'util::prefs',
+            'script_runtime::{store_panic_result, maybe_take_panic_result}',
             'std::borrow::ToOwned',
             'std::cmp',
             'std::mem',
             'std::num',
             'std::os',
+            'std::panic::{self, AssertUnwindSafe}',
             'std::ptr',
             'std::str',
             'std::rc',
@@ -6088,6 +6104,9 @@ class CallbackMethod(CallbackMember):
             "        length_: ${argc} as ::libc::size_t,\n"
             "        elements_: ${argv}\n"
             "    }, rval.handle_mut());\n"
+            "if let Some(error) = maybe_take_panic_result() {\n"
+            "    panic::resume_unwind(error);\n"
+            "}\n"
             "if !ok {\n"
             "    return Err(JSFailed);\n"
             "}\n").substitute(replacements)

components/script/dom/window.rs

@@ -61,7 +61,7 @@ use script_layout_interface::message::{Msg, Reflow, ReflowQueryType, ScriptReflo
 use script_layout_interface::reporter::CSSErrorReporter;
 use script_layout_interface::rpc::{ContentBoxResponse, ContentBoxesResponse, LayoutRPC};
 use script_layout_interface::rpc::{MarginStyleResponse, ResolvedStyleResponse};
-use script_runtime::{ScriptChan, ScriptPort};
+use script_runtime::{ScriptChan, ScriptPort, maybe_take_panic_result};
 use script_thread::SendableMainThreadScriptChan;
 use script_thread::{MainThreadScriptChan, MainThreadScriptMsg, RunnableWrapper};
 use script_traits::{ConstellationControlMsg, UntrustedNodeAddress};
@@ -74,6 +74,7 @@ use std::collections::{HashMap, HashSet};
 use std::default::Default;
 use std::ffi::CString;
 use std::io::{Write, stderr, stdout};
+use std::panic;
 use std::rc::Rc;
 use std::sync::atomic::{AtomicBool, Ordering};
 use std::sync::mpsc::TryRecvError::{Disconnected, Empty};
@@ -914,6 +915,10 @@ impl<'a, T: Reflectable> ScriptHelpers for &'a T {
                         report_pending_exception(cx, globalhandle.get());
                     }
                 }
+
+                if let Some(error) = maybe_take_panic_result() {
+                    panic::resume_unwind(error);
+                }
             }
         )
     }

components/script/dom/workerglobalscope.rs

@@ -28,11 +28,12 @@ use msg::constellation_msg::{PipelineId, ReferrerPolicy, PanicMsg};
 use net_traits::{LoadContext, ResourceThreads, load_whole_resource};
 use net_traits::{RequestSource, LoadOrigin, CustomResponseSender, IpcSend};
 use profile_traits::{mem, time};
-use script_runtime::{CommonScriptMsg, ScriptChan, ScriptPort};
+use script_runtime::{CommonScriptMsg, ScriptChan, ScriptPort, maybe_take_panic_result};
 use script_traits::ScriptMsg as ConstellationMsg;
 use script_traits::{MsDuration, TimerEvent, TimerEventId, TimerEventRequest, TimerSource};
 use std::cell::Cell;
 use std::default::Default;
+use std::panic;
 use std::rc::Rc;
 use std::sync::Arc;
 use std::sync::atomic::{AtomicBool, Ordering};
@@ -320,8 +321,14 @@ impl WorkerGlobalScopeMethods for WorkerGlobalScope {
                 }
             };
 
-            match self.runtime.evaluate_script(
-                self.reflector().get_jsobject(), &source, url.as_str(), 1, rval.handle_mut()) {
+            let result = self.runtime.evaluate_script(
+                self.reflector().get_jsobject(), &source, url.as_str(), 1, rval.handle_mut());
+
+            if let Some(error) = maybe_take_panic_result() {
+                panic::resume_unwind(error);
+            }
+
+            match result {
                 Ok(_) => (),
                 Err(_) => {
                     println!("evaluate_script failed");

components/script/script_runtime.rs

@@ -19,7 +19,8 @@ use js::jsapi::{JSObject, RuntimeOptionsRef, SetPreserveWrapperCallback};
 use js::rust::Runtime;
 use profile_traits::mem::{Report, ReportKind, ReportsChan};
 use script_thread::{Runnable, STACK_ROOTS, trace_thread};
-use std::cell::Cell;
+use std::any::Any;
+use std::cell::{RefCell, Cell};
 use std::io::{Write, stdout};
 use std::marker::PhantomData;
 use std::os;
@@ -321,6 +322,21 @@ pub fn get_reports(cx: *mut JSContext, path_seg: String) -> Vec<Report> {
     reports
 }
 
+thread_local!(static PANIC_RESULT: RefCell<Option<Box<Any + Send>>> = RefCell::new(None));
+
+pub fn store_panic_result(error: Box<Any + Send>) {
+    PANIC_RESULT.with(|result| {
+        assert!(result.borrow().is_none());
+        *result.borrow_mut() = Some(error);
+    });
+}
+
+pub fn maybe_take_panic_result() -> Option<Box<Any + Send>> {
+    PANIC_RESULT.with(|result| {
+        result.borrow_mut().take()
+    })
+}
+
 thread_local!(static GC_CYCLE_START: Cell<Option<Tm>> = Cell::new(None));
 thread_local!(static GC_SLICE_START: Cell<Option<Tm>> = Cell::new(None));