v8/test/inspector/debugger/wasm-stepping.js

// Copyright 2020 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

utils.load('test/inspector/wasm-inspector-test.js');

let {session, contextGroup, Protocol} =
    InspectorTest.start('Tests stepping through wasm scripts by byte offsets');
session.setupScriptMap();

var builder = new WasmModuleBuilder();

var func_a_idx =
    builder.addFunction('wasm_A', kSig_v_i).addBody([kExprNop, kExprNop]).index;

// wasm_B calls wasm_A <param0> times.
var func_b = builder.addFunction('wasm_B', kSig_v_i)
    .addBody([
      // clang-format off
      kExprLoop, kWasmStmt,               // while
        kExprLocalGet, 0,                 // -
        kExprIf, kWasmStmt,               // if <param0> != 0
          kExprLocalGet, 0,               // -
          kExprI32Const, 1,               // -
          kExprI32Sub,                    // -
          kExprLocalSet, 0,               // decrease <param0>
          ...wasmI32Const(1024),          // some longer i32 const (2 byte imm)
          kExprCallFunction, func_a_idx,  // -
          kExprBr, 1,                     // continue
          kExprEnd,                       // -
        kExprEnd,                         // break
      // clang-format on
    ])
    .exportAs('main');

let fact = builder.addFunction('fact', kSig_i_i)
    .addLocals(kWasmI32, 1)
    .addBody([
    // clang-format off
    kExprLocalGet, 0,
    kExprIf, kWasmI32,               // if <param0> != 0
      kExprLocalGet, 0,
      kExprI32Const, 1,
      kExprI32Sub,
      kExprCallFunction, 2,
      kExprLocalGet, 0,
      kExprI32Mul,                   //   return fact(<param0> - 1) * <param0>
    kExprElse,                       // else
      kExprI32Const, 1,              //   return 1
    kExprEnd,
    // clang-format on
  ])
  .exportAs('fact');

var module_bytes = builder.toArray();

InspectorTest.runAsyncTestSuite([
  async function test() {
    for (const action of ['stepInto', 'stepOver', 'stepOut', 'resume'])
      InspectorTest.logProtocolCommandCalls('Debugger.' + action);

    await Protocol.Debugger.enable();
    InspectorTest.log('Setting up global instance variable.');
    WasmInspectorTest.instantiate(module_bytes);
    const [, {params: wasmScript}] = await Protocol.Debugger.onceScriptParsed(2);

    InspectorTest.log('Got wasm script: ' + wasmScript.url);

    // Set the breakpoint on a non-breakable position. This should resolve to the
    // next instruction.
    var offset = func_b.body_offset + 15;
    InspectorTest.log(
        `Setting breakpoint on offset ` + offset + ` (should be propagated to ` +
          (offset + 1) + `, the offset of the call), url ${wasmScript.url}`);
    let bpmsg = await Protocol.Debugger.setBreakpoint({
      location: {scriptId: wasmScript.scriptId, lineNumber: 0, columnNumber: offset}
    });

    InspectorTest.logMessage(bpmsg.result.actualLocation);
    Protocol.Runtime.evaluate({ expression: 'instance.exports.main(4)' });
    await waitForPauseAndStep('stepInto');  // into call to wasm_A
    await waitForPauseAndStep('stepOver');  // over first nop
    await waitForPauseAndStep('stepOut');   // out of wasm_A
    await waitForPauseAndStep('stepOut');   // out of wasm_B, stop on breakpoint
    await waitForPauseAndStep('stepOver');  // over call
    await waitForPauseAndStep('stepInto');  // == stepOver br
    await waitForPauseAndStep('resume');    // to next breakpoint (3rd iteration)
    await waitForPauseAndStep('stepInto');  // into wasm_A
    await waitForPauseAndStep('stepOut');   // out to wasm_B
    // Now step 10 times, until we are in wasm_A again.
    for (let i = 0; i < 10; ++i) await waitForPauseAndStep('stepInto');
    // 3 more times, back to wasm_B.
    for (let i = 0; i < 3; ++i) await waitForPauseAndStep('stepInto');
    // Then just resume.
    await waitForPauseAndStep('resume');
    InspectorTest.log('exports.main returned!');

    InspectorTest.log('Test stepping over a recursive call');
    // Set a breakpoint at the recursive call and run.
    offset = fact.body_offset + 9; // Offset of the recursive call instruction.
    InspectorTest.log(
        `Setting breakpoint on the recursive call instruction @+` + offset +
        `, url ${wasmScript.url}`);
    bpmsg = await Protocol.Debugger.setBreakpoint({
      location: {scriptId: wasmScript.scriptId, lineNumber: 0, columnNumber: offset}
    });
    actualLocation = bpmsg.result.actualLocation;
    InspectorTest.logMessage(actualLocation);
    Protocol.Runtime.evaluate({ expression: 'instance.exports.fact(4)' });
    await waitForPause();

    // Remove the breakpoint before stepping over.
    InspectorTest.log('Removing breakpoint');
    let breakpointId = bpmsg.result.breakpointId;
    await Protocol.Debugger.removeBreakpoint({breakpointId});
    await Protocol.Debugger.stepOver();
    await waitForPauseAndStep('resume');
  }
]);

async function waitForPauseAndStep(stepAction) {
  await waitForPause();
  Protocol.Debugger[stepAction]();
}

async function waitForPause() {
  const {params: {callFrames}} = await Protocol.Debugger.oncePaused();
  await session.logSourceLocation(callFrames[0].location);
}