[wasm][debugger] Avoid using Uint8Array to set memory content (#60087)

* Creating a test case for PR #59773
But I'm not using Uint8Array to set the content on memory allocated using malloc as @lewing suggested in the same PR.

* add lines in the eof

* Change the function that allocate memory.

* adding comment as suggested by @kg

* Accepting @lewing suggestion

src/mono/wasm/debugger/DebuggerTestSuite/Tests.cs

@@ -860,6 +860,47 @@ await EvaluateAndCheck(
             );
         }
 
+        [Fact]
+        public async Task MallocUntilReallocate() //https://github.com/xamarin/xamarin-android/issues/6161
+        {
+            string eval_expr = "window.setTimeout(function() { malloc_to_reallocate_test (); }, 1)";
+
+            var result = await cli.SendCommand("Runtime.evaluate", JObject.FromObject(new { expression = eval_expr }), token);
+
+            var bp = await SetBreakpoint("dotnet://debugger-test.dll/debugger-test.cs", 10, 8);
+
+            var eval_req = JObject.FromObject(new
+            {
+                expression = "window.setTimeout(function() { invoke_add(); }, 1);",
+            });
+
+            await EvaluateAndCheck(
+                "window.setTimeout(function() { invoke_add(); }, 1);",
+                "dotnet://debugger-test.dll/debugger-test.cs", 10, 8,
+                "IntAdd",
+                wait_for_event_fn: (pause_location) =>
+                {
+                    Assert.Equal("other", pause_location["reason"]?.Value<string>());
+                    Assert.Equal(bp.Value["breakpointId"]?.ToString(), pause_location["hitBreakpoints"]?[0]?.Value<string>());
+
+                    var top_frame = pause_location["callFrames"][0];
+                    Assert.Equal("IntAdd", top_frame["functionName"].Value<string>());
+                    Assert.Contains("debugger-test.cs", top_frame["url"].Value<string>());
+
+                    CheckLocation("dotnet://debugger-test.dll/debugger-test.cs", 8, 4, scripts, top_frame["functionLocation"]);
+
+                    //now check the scope
+                    var scope = top_frame["scopeChain"][0];
+                    Assert.Equal("local", scope["type"]);
+                    Assert.Equal("IntAdd", scope["name"]);
+
+                    Assert.Equal("object", scope["object"]["type"]);
+                    CheckLocation("dotnet://debugger-test.dll/debugger-test.cs", 8, 4, scripts, scope["startLocation"]);
+                    CheckLocation("dotnet://debugger-test.dll/debugger-test.cs", 14, 4, scripts, scope["endLocation"]);
+                    return Task.CompletedTask;
+                }
+            );
+        }
         //TODO add tests covering basic stepping behavior as step in/out/over
     }
 }

src/mono/wasm/debugger/tests/debugger-test/other.js

@@ -95,3 +95,9 @@ function get_properties_test () {
 
 	console.log(`break here`);
 }
+
+function malloc_to_reallocate_test () {
+	//need to allocate this buffer size to force wasm linear memory to grow 
+	var _debugger_buffer = Module._malloc(4500000);
+	Module._free(_debugger_buffer);
+}

src/mono/wasm/runtime/base64.ts

@@ -108,14 +108,3 @@ function _makeByteReader(bytes: Uint8Array, index?: number, count?: number): {
 
     return result;
 }
-
-// FIXME: improve
-export function _base64_to_uint8(base64String: string):Uint8Array {
-    const byteCharacters = atob(base64String);
-    const byteNumbers = new Array(byteCharacters.length);
-    for (let i = 0; i < byteCharacters.length; i++) {
-        byteNumbers[i] = byteCharacters.charCodeAt(i);
-    }
-
-    return new Uint8Array(byteNumbers);
-}

src/mono/wasm/runtime/debug.ts

@@ -2,15 +2,14 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 
 import { Module, runtimeHelpers } from "./modules";
-import { toBase64StringImpl, _base64_to_uint8 } from "./base64";
+import { toBase64StringImpl } from "./base64";
 import cwraps from "./cwraps";
 
 let commands_received: CommandResponse;
 let _call_function_res_cache: any = {};
 let _next_call_function_res_id = 0;
 let _debugger_buffer_len = -1;
 let _debugger_buffer: VoidPtr;
-let _debugger_heap_bytes: Uint8Array;
 
 export function mono_wasm_runtime_ready(): void {
     runtimeHelpers.mono_wasm_runtime_is_ready = true;
@@ -52,9 +51,10 @@ function mono_wasm_malloc_and_set_debug_buffer(command_parameters: string) {
         _debugger_buffer_len = Math.max(command_parameters.length, _debugger_buffer_len, 256);
         _debugger_buffer = Module._malloc(_debugger_buffer_len);
     }
-    //reset _debugger_heap_bytes because Module.HEAPU8.buffer can be reallocated 
-    _debugger_heap_bytes = new Uint8Array(Module.HEAPU8.buffer, <any>_debugger_buffer, _debugger_buffer_len);
-    _debugger_heap_bytes.set(_base64_to_uint8(command_parameters));
+    const byteCharacters = atob(command_parameters);
+    for (let i = 0; i < byteCharacters.length; i++) {
+        Module.HEAPU8[<any>_debugger_buffer + i] = byteCharacters.charCodeAt(i);
+    }
 }
 
 export function mono_wasm_send_dbg_command_with_parms(id: number, command_set: number, command: number, command_parameters: string, length: number, valtype: number, newvalue: number): CommandResponseResult {