1 files changed, 26 insertions, 34 deletions

diff --git a/ui/src/engine/wasm_bridge.ts b/ui/src/engine/wasm_bridge.ts
index fe896b169..97a36927c 100644
--- a/ui/src/engine/wasm_bridge.ts
+++ b/ui/src/engine/wasm_bridge.ts
@@ -23,6 +23,10 @@ import * as init_trace_processor from '../gen/trace_processor';
 // HEAPU8[reqBufferAddr, +REQ_BUFFER_SIZE].
 const REQ_BUF_SIZE = 32 * 1024 * 1024;
 
+function writeToUIConsole(line: string) {
+  console.log(line);
+}
+
 export interface WasmBridgeRequest {
   id: number;
   methodName: string;
@@ -31,6 +35,7 @@ export interface WasmBridgeRequest {
 
 export interface WasmBridgeResponse {
   id: number;
+  aborted: boolean;  // If true the WASM module crashed.
   data: Uint8Array;
 }
 
@@ -42,7 +47,6 @@ export class WasmBridge {
   private currentRequestResult: WasmBridgeResponse|null;
   private connection: init_trace_processor.Module;
   private reqBufferAddr = 0;
-  private lastStderr: string[] = [];
 
   constructor(init: init_trace_processor.InitWasm) {
     this.aborted = false;
@@ -51,12 +55,13 @@ export class WasmBridge {
     const deferredRuntimeInitialized = defer<void>();
     this.connection = init({
       locateFile: (s: string) => s,
-      print: (line: string) => console.log(line),
-      printErr: (line: string) => this.appendAndLogErr(line),
+      print: writeToUIConsole,
+      printErr: writeToUIConsole,
       onRuntimeInitialized: () => deferredRuntimeInitialized.resolve(),
+      onAbort: () => this.aborted = true,
     });
     this.whenInitialized = deferredRuntimeInitialized.then(() => {
-      const fn = this.connection.addFunction(this.onReply.bind(this), 'vii');
+      const fn = this.connection.addFunction(this.onReply.bind(this), 'iii');
       this.reqBufferAddr = this.connection.ccall(
           'Initialize',
           /*return=*/ 'number',
@@ -67,31 +72,26 @@ export class WasmBridge {
 
   callWasm(req: WasmBridgeRequest): WasmBridgeResponse {
     if (this.aborted) {
-      throw new Error('Wasm module crashed');
+      return {
+        id: req.id,
+        aborted: true,
+        data: new Uint8Array(),
+      };
     }
     assertTrue(req.data.length <= REQ_BUF_SIZE);
     const endAddr = this.reqBufferAddr + req.data.length;
     this.connection.HEAPU8.subarray(this.reqBufferAddr, endAddr).set(req.data);
-    try {
-      this.connection.ccall(
-          req.methodName,    // C method name.
-          'void',            // Return type.
-          ['number'],        // Arg types.
-          [req.data.length]  // Args.
-      );
-      const result = assertExists(this.currentRequestResult);
-      this.currentRequestResult = null;
-      result.id = req.id;
-      return result;
-    } catch (err) {
-      this.aborted = true;
-      let abortReason = `${err}`;
-      if (err instanceof Error) {
-        abortReason = `${err.name}: ${err.message}\n${err.stack}`;
-      }
-      abortReason += '\n\nstderr: \n' + this.lastStderr.join('\n');
-      throw new Error(abortReason);
-    }
+    this.connection.ccall(
+        req.methodName,    // C method name.
+        'void',            // Return type.
+        ['number'],        // Arg types.
+        [req.data.length]  // Args.
+    );
+
+    const result = assertExists(this.currentRequestResult);
+    this.currentRequestResult = null;
+    result.id = req.id;
+    return result;
   }
 
   // This is invoked from ccall in the same call stack as callWasm.
@@ -99,16 +99,8 @@ export class WasmBridge {
     const data = this.connection.HEAPU8.slice(heapPtr, heapPtr + size);
     this.currentRequestResult = {
       id: 0,  // Will be set by callWasm()'s epilogue.
+      aborted: false,
       data,
     };
   }
-
-  private appendAndLogErr(line: string) {
-    console.warn(line);
-    // Keep the last N lines in the |lastStderr| buffer.
-    this.lastStderr.push(line);
-    if (this.lastStderr.length > 512) {
-      this.lastStderr.shift();
-    }
-  }
 }