[inspector] Expose GetPossibleBreakpoints for wasm

and add an inspector test for it. Also test that a breakpoint can be
set on each reported position, and that it is also hit during
execution.
This CL also fixes two little things which were uncovered by the new
test.

R=yangguo@chromium.org, titzer@chromium.org, kozyatinskiy@chromium.org
BUG=v8:5822

Review-Url: https://codereview.chromium.org/2655653003
Cr-Commit-Position: refs/heads/master@{#42722}

src/api.cc

@@ -9151,8 +9151,9 @@ bool debug::Script::GetPossibleBreakpoints(
   CHECK(!start.IsEmpty());
   i::Handle<i::Script> script = Utils::OpenHandle(this);
   if (script->type() == i::Script::TYPE_WASM) {
-    // TODO(clemensh): Return the proper thing once we support wasm breakpoints.
-    return false;
+    i::Handle<i::WasmCompiledModule> compiled_module(
+        i::WasmCompiledModule::cast(script->wasm_compiled_module()));
+    return compiled_module->GetPossibleBreakpoints(start, end, locations);
   }
 
   i::Script::InitLineEnds(script);
@@ -9248,8 +9249,26 @@ int debug::WasmScript::NumImportedFunctions() const {
   return static_cast<int>(compiled_module->module()->num_imported_functions);
 }
 
+std::pair<int, int> debug::WasmScript::GetFunctionRange(
+    int function_index) const {
+  i::DisallowHeapAllocation no_gc;
+  i::Handle<i::Script> script = Utils::OpenHandle(this);
+  DCHECK_EQ(i::Script::TYPE_WASM, script->type());
+  i::WasmCompiledModule* compiled_module =
+      i::WasmCompiledModule::cast(script->wasm_compiled_module());
+  DCHECK_LE(0, function_index);
+  DCHECK_GT(compiled_module->module()->functions.size(), function_index);
+  i::wasm::WasmFunction& func =
+      compiled_module->module()->functions[function_index];
+  DCHECK_GE(i::kMaxInt, func.code_start_offset);
+  DCHECK_GE(i::kMaxInt, func.code_end_offset);
+  return std::make_pair(static_cast<int>(func.code_start_offset),
+                        static_cast<int>(func.code_end_offset));
+}
+
 debug::WasmDisassembly debug::WasmScript::DisassembleFunction(
     int function_index) const {
+  i::DisallowHeapAllocation no_gc;
   i::Handle<i::Script> script = Utils::OpenHandle(this);
   DCHECK_EQ(i::Script::TYPE_WASM, script->type());
   i::WasmCompiledModule* compiled_module =

src/debug/debug-interface.h

@@ -139,6 +139,8 @@ class WasmScript : public Script {
   int NumFunctions() const;
   int NumImportedFunctions() const;
 
+  std::pair<int, int> GetFunctionRange(int function_index) const;
+
   debug::WasmDisassembly DisassembleFunction(int function_index) const;
 };
 

src/inspector/v8-debugger-agent-impl.cc

@@ -473,6 +473,7 @@ V8DebuggerAgentImpl::resolveBreakpoint(const String16& breakpointId,
       scriptIterator->second->endLine() < breakpoint.line_number)
     return nullptr;
 
+  // Translate from protocol location to v8 location for the debugger.
   ScriptBreakpoint translatedBreakpoint = breakpoint;
   m_debugger->wasmTranslation()->TranslateProtocolLocationToWasmScriptLocation(
       &translatedBreakpoint.script_id, &translatedBreakpoint.line_number,
@@ -484,6 +485,10 @@ V8DebuggerAgentImpl::resolveBreakpoint(const String16& breakpointId,
       translatedBreakpoint, &actualLineNumber, &actualColumnNumber);
   if (debuggerBreakpointId.isEmpty()) return nullptr;
 
+  // Translate back from v8 location to protocol location for the return value.
+  m_debugger->wasmTranslation()->TranslateWasmScriptLocationToProtocolLocation(
+      &translatedBreakpoint.script_id, &actualLineNumber, &actualColumnNumber);
+
   m_serverBreakpoints[debuggerBreakpointId] =
       std::make_pair(breakpointId, source);
   CHECK(!breakpointId.isEmpty());

src/inspector/v8-debugger-script.cc

@@ -6,6 +6,7 @@
 
 #include "src/inspector/inspected-context.h"
 #include "src/inspector/string-util.h"
+#include "src/inspector/wasm-translation.h"
 
 namespace v8_inspector {
 
@@ -69,6 +70,32 @@ String16 calculateHash(const String16& str) {
   return hash.toString();
 }
 
+void TranslateProtocolLocationToV8Location(WasmTranslation* wasmTranslation,
+                                           v8::debug::Location* loc,
+                                           const String16& scriptId,
+                                           const String16& expectedV8ScriptId) {
+  if (loc->IsEmpty()) return;
+  int lineNumber = loc->GetLineNumber();
+  int columnNumber = loc->GetColumnNumber();
+  String16 translatedScriptId = scriptId;
+  wasmTranslation->TranslateProtocolLocationToWasmScriptLocation(
+      &translatedScriptId, &lineNumber, &columnNumber);
+  DCHECK_EQ(expectedV8ScriptId.utf8(), translatedScriptId.utf8());
+  *loc = v8::debug::Location(lineNumber, columnNumber);
+}
+
+void TranslateV8LocationToProtocolLocation(
+    WasmTranslation* wasmTranslation, v8::debug::Location* loc,
+    const String16& scriptId, const String16& expectedProtocolScriptId) {
+  int lineNumber = loc->GetLineNumber();
+  int columnNumber = loc->GetColumnNumber();
+  String16 translatedScriptId = scriptId;
+  wasmTranslation->TranslateWasmScriptLocationToProtocolLocation(
+      &translatedScriptId, &lineNumber, &columnNumber);
+  DCHECK_EQ(expectedProtocolScriptId.utf8(), translatedScriptId.utf8());
+  *loc = v8::debug::Location(lineNumber, columnNumber);
+}
+
 class ActualScript : public V8DebuggerScript {
   friend class V8DebuggerScript;
 
@@ -171,11 +198,12 @@ class WasmVirtualScript : public V8DebuggerScript {
   friend class V8DebuggerScript;
 
  public:
-  WasmVirtualScript(v8::Isolate* isolate,
+  WasmVirtualScript(v8::Isolate* isolate, WasmTranslation* wasmTranslation,
                     v8::Local<v8::debug::WasmScript> script, String16 id,
                     String16 url, String16 source)
       : V8DebuggerScript(isolate, std::move(id), std::move(url)),
-        m_script(isolate, script) {
+        m_script(isolate, script),
+        m_wasmTranslation(wasmTranslation) {
     int num_lines = 0;
     int last_newline = -1;
     size_t next_newline = source.find('\n', last_newline + 1);
@@ -196,10 +224,31 @@ class WasmVirtualScript : public V8DebuggerScript {
   bool getPossibleBreakpoints(
       const v8::debug::Location& start, const v8::debug::Location& end,
       std::vector<v8::debug::Location>* locations) override {
-    // TODO(clemensh): Returning false produces the protocol error "Internal
-    // error". Implement and fix expected output of
-    // wasm-get-breakable-locations.js.
-    return false;
+    v8::HandleScope scope(m_isolate);
+    v8::Local<v8::debug::Script> script = m_script.Get(m_isolate);
+    String16 v8ScriptId = String16::fromInteger(script->Id());
+
+    v8::debug::Location translatedStart = start;
+    TranslateProtocolLocationToV8Location(m_wasmTranslation, &translatedStart,
+                                          scriptId(), v8ScriptId);
+
+    v8::debug::Location translatedEnd = end;
+    if (translatedEnd.IsEmpty()) {
+      // Stop before the start of the next function.
+      translatedEnd =
+          v8::debug::Location(translatedStart.GetLineNumber() + 1, 0);
+    } else {
+      TranslateProtocolLocationToV8Location(m_wasmTranslation, &translatedEnd,
+                                            scriptId(), v8ScriptId);
+    }
+
+    bool success = script->GetPossibleBreakpoints(translatedStart,
+                                                  translatedEnd, locations);
+    for (v8::debug::Location& loc : *locations) {
+      TranslateV8LocationToProtocolLocation(m_wasmTranslation, &loc, v8ScriptId,
+                                            scriptId());
+    }
+    return success;
   }
 
   void resetBlackboxedStateCache() override {}
@@ -211,6 +260,7 @@ class WasmVirtualScript : public V8DebuggerScript {
   }
 
   v8::Global<v8::debug::WasmScript> m_script;
+  WasmTranslation* m_wasmTranslation;
 };
 
 }  // namespace
@@ -223,11 +273,12 @@ std::unique_ptr<V8DebuggerScript> V8DebuggerScript::Create(
 }
 
 std::unique_ptr<V8DebuggerScript> V8DebuggerScript::CreateWasm(
-    v8::Isolate* isolate, v8::Local<v8::debug::WasmScript> underlyingScript,
-    String16 id, String16 url, String16 source) {
+    v8::Isolate* isolate, WasmTranslation* wasmTranslation,
+    v8::Local<v8::debug::WasmScript> underlyingScript, String16 id,
+    String16 url, String16 source) {
   return std::unique_ptr<WasmVirtualScript>(
-      new WasmVirtualScript(isolate, underlyingScript, std::move(id),
-                            std::move(url), std::move(source)));
+      new WasmVirtualScript(isolate, wasmTranslation, underlyingScript,
+                            std::move(id), std::move(url), std::move(source)));
 }
 
 V8DebuggerScript::V8DebuggerScript(v8::Isolate* isolate, String16 id,

src/inspector/v8-debugger-script.h

@@ -39,14 +39,18 @@
 
 namespace v8_inspector {
 
+// Forward declaration.
+class WasmTranslation;
+
 class V8DebuggerScript {
  public:
   static std::unique_ptr<V8DebuggerScript> Create(
       v8::Isolate* isolate, v8::Local<v8::debug::Script> script,
       bool isLiveEdit);
   static std::unique_ptr<V8DebuggerScript> CreateWasm(
-      v8::Isolate* isolate, v8::Local<v8::debug::WasmScript> underlyingScript,
-      String16 id, String16 url, String16 source);
+      v8::Isolate* isolate, WasmTranslation* wasmTranslation,
+      v8::Local<v8::debug::WasmScript> underlyingScript, String16 id,
+      String16 url, String16 source);
 
   virtual ~V8DebuggerScript();
 

src/runtime/runtime-debug.cc

@@ -1653,7 +1653,8 @@ namespace {
 int ScriptLinePositionWithOffset(Handle<Script> script, int line, int offset) {
   if (line < 0 || offset < 0) return -1;
 
-  if (line == 0) return ScriptLinePosition(script, line) + offset;
+  if (line == 0 || offset == 0)
+    return ScriptLinePosition(script, line) + offset;
 
   Script::PositionInfo info;
   if (!Script::GetPositionInfo(script, offset, &info, Script::NO_OFFSET)) {

src/runtime/runtime-wasm.cc

@@ -169,6 +169,10 @@ RUNTIME_FUNCTION(Runtime_WasmRunInterpreter) {
   CHECK(arg_buffer_obj->IsSmi());
   uint8_t* arg_buffer = reinterpret_cast<uint8_t*>(*arg_buffer_obj);
 
+  // Set the current isolate's context, saving the previous one.
+  SaveContext save(isolate);
+  isolate->set_context(*instance->compiled_module()->native_context());
+
   instance->debug_info()->RunInterpreter(func_index, arg_buffer);
   return isolate->heap()->undefined_value();
 }

test/inspector/debugger/wasm-get-breakable-locations-expected.txt

+Running testFunction...
+Script nr 0 parsed. URL: v8://test/setup
+Script nr 1 parsed. URL: v8://test/runTestFunction
+Script nr 2 parsed. URL: wasm://wasm/wasm-824d794e/wasm-824d794e-0
+This is a wasm script (nr 0).
+Script nr 3 parsed. URL: wasm://wasm/wasm-824d794e/wasm-824d794e-1
+This is a wasm script (nr 1).
+Querying breakable locations for all wasm scripts now...
+Requesting all breakable locations in wasm script 0
+4 breakable location(s):
+[0] 2:2 ||   >nop
+[1] 3:2 ||   >i32.const 12
+[2] 4:2 ||   >set_local 0
+[3] 5:0 || >end
+Requesting breakable locations in lines [0,3)
+1 breakable location(s):
+[0] 2:2 ||   >nop
+Requesting breakable locations in lines [4,6)
+2 breakable location(s):
+[0] 4:2 ||   >set_local 0
+[1] 5:0 || >end
+Requesting all breakable locations in wasm script 1
+7 breakable location(s):
+[0] 1:2 ||   >get_local 0
+[1] 2:2 ||   >if
+[2] 3:4 ||     >block
+[3] 4:6 ||       >call 0
+[4] 5:4 ||     >end
+[5] 6:2 ||   >end
+[6] 7:0 || >end
+Requesting breakable locations in lines [0,3)
+2 breakable location(s):
+[0] 1:2 ||   >get_local 0
+[1] 2:2 ||   >if
+Requesting breakable locations in lines [4,6)
+2 breakable location(s):
+[0] 4:6 ||       >call 0
+[1] 5:4 ||     >end
+Setting a breakpoint on each breakable location...
+Setting at wasm://wasm/wasm-824d794e/wasm-824d794e-0:2:2
+Success!
+Setting at wasm://wasm/wasm-824d794e/wasm-824d794e-0:3:2
+Success!
+Setting at wasm://wasm/wasm-824d794e/wasm-824d794e-0:4:2
+Success!
+Setting at wasm://wasm/wasm-824d794e/wasm-824d794e-0:5:0
+Success!
+Setting at wasm://wasm/wasm-824d794e/wasm-824d794e-1:1:2
+Success!
+Setting at wasm://wasm/wasm-824d794e/wasm-824d794e-1:2:2
+Success!
+Setting at wasm://wasm/wasm-824d794e/wasm-824d794e-1:3:4
+Success!
+Setting at wasm://wasm/wasm-824d794e/wasm-824d794e-1:4:6
+Success!
+Setting at wasm://wasm/wasm-824d794e/wasm-824d794e-1:5:4
+Success!
+Setting at wasm://wasm/wasm-824d794e/wasm-824d794e-1:6:2
+Success!
+Setting at wasm://wasm/wasm-824d794e/wasm-824d794e-1:7:0
+Success!
+Running wasm code...
+Missing breakpoints: 11
+Script nr 4 parsed. URL: v8://test/runWasm
+Stopped at wasm://wasm/wasm-824d794e/wasm-824d794e-1:1:2
+Missing breakpoints: 10
+Stopped at wasm://wasm/wasm-824d794e/wasm-824d794e-1:2:2
+Missing breakpoints: 9
+Stopped at wasm://wasm/wasm-824d794e/wasm-824d794e-1:3:4
+Missing breakpoints: 8
+Stopped at wasm://wasm/wasm-824d794e/wasm-824d794e-1:4:6
+Missing breakpoints: 7
+Stopped at wasm://wasm/wasm-824d794e/wasm-824d794e-0:2:2
+Missing breakpoints: 6
+Stopped at wasm://wasm/wasm-824d794e/wasm-824d794e-0:3:2
+Missing breakpoints: 5
+Stopped at wasm://wasm/wasm-824d794e/wasm-824d794e-0:4:2
+Missing breakpoints: 4
+Stopped at wasm://wasm/wasm-824d794e/wasm-824d794e-0:5:0
+Missing breakpoints: 3
+Stopped at wasm://wasm/wasm-824d794e/wasm-824d794e-1:5:4
+Missing breakpoints: 2
+Stopped at wasm://wasm/wasm-824d794e/wasm-824d794e-1:6:2
+Missing breakpoints: 1
+Stopped at wasm://wasm/wasm-824d794e/wasm-824d794e-1:7:0
+Missing breakpoints: 0
+Finished!

test/inspector/debugger/wasm-get-breakable-locations.js

+// Copyright 2016 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.
+
+// Flags: --expose-wasm
+
+load('test/mjsunit/wasm/wasm-constants.js');
+load('test/mjsunit/wasm/wasm-module-builder.js');
+
+var builder = new WasmModuleBuilder();
+
+// clang-format off
+var func_idx = builder.addFunction('helper', kSig_v_v)
+    .addLocals({i32_count: 1})
+    .addBody([
+        kExprNop,
+        kExprI32Const, 12,
+        kExprSetLocal, 0,
+    ]).index;
+
+builder.addFunction('main', kSig_v_i)
+    .addBody([
+        kExprGetLocal, 0,
+        kExprIf, kWasmStmt,
+          kExprBlock, kWasmStmt,
+            kExprCallFunction, func_idx,
+          kExprEnd,
+        kExprEnd
+    ]).exportAs('main');
+// clang-format on
+
+var module_bytes = builder.toArray();
+
+function testFunction(bytes) {
+  var buffer = new ArrayBuffer(bytes.length);
+  var view = new Uint8Array(buffer);
+  for (var i = 0; i < bytes.length; i++) {
+    view[i] = bytes[i] | 0;
+  }
+
+  var module = new WebAssembly.Module(buffer);
+  // Set global variable.
+  instance = new WebAssembly.Instance(module);
+}
+
+var evalWithUrl = (code, url) => Protocol.Runtime.evaluate(
+    {'expression': code + '\n//# sourceURL=v8://test/' + url});
+
+var setupCode = testFunction.toString() + ';\nvar module_bytes = ' +
+    JSON.stringify(module_bytes) + ';\nvar instance;';
+
+Protocol.Debugger.enable();
+Protocol.Debugger.onScriptParsed(handleScriptParsed);
+InspectorTest.log('Running testFunction...');
+evalWithUrl(setupCode, 'setup')
+    .then(() => evalWithUrl('testFunction(module_bytes)', 'runTestFunction'))
+    .then(getBreakableLocationsForAllWasmScripts)
+    .then(setAllBreakableLocations)
+    .then(() => InspectorTest.log('Running wasm code...'))
+    .then(() => (evalWithUrl('instance.exports.main(1)', 'runWasm'), 0))
+    .then(waitForAllPauses)
+    .then(() => InspectorTest.log('Finished!'))
+    .then(InspectorTest.completeTest);
+
+var allBreakableLocations = [];
+
+var urls = {};
+var numScripts = 0;
+var wasmScripts = [];
+function handleScriptParsed(messageObject) {
+  var scriptId = messageObject.params.scriptId;
+  var url = messageObject.params.url;
+  urls[scriptId] = url;
+  InspectorTest.log('Script nr ' + numScripts + ' parsed. URL: ' + url);
+  ++numScripts;
+
+  if (url.startsWith('wasm://')) {
+    InspectorTest.log('This is a wasm script (nr ' + wasmScripts.length + ').');
+    wasmScripts.push(scriptId);
+  }
+}
+
+function printFailure(message) {
+  if (!message.result) {
+    InspectorTest.logMessage(message);
+  }
+  return message;
+}
+
+function printBreakableLocations(message, expectedScriptId, source) {
+  var lines = source.split('\n');
+  var locations = message.result.locations;
+  InspectorTest.log(locations.length + ' breakable location(s):');
+  for (var i = 0; i < locations.length; ++i) {
+    if (locations[i].scriptId != expectedScriptId) {
+      InspectorTest.log(
+          'SCRIPT ID MISMATCH!! ' + locations[i].scriptId + ' != ' +
+          expectedScriptId);
+    }
+    var line = '<illegal line number>';
+    if (locations[i].lineNumber < lines.length) {
+      line = lines[locations[i].lineNumber];
+      if (locations[i].columnNumber < line.length) {
+        line = line.substr(0, locations[i].columnNumber) + '>' +
+            line.substr(locations[i].columnNumber);
+      }
+    }
+    InspectorTest.log(
+        '[' + i + '] ' + locations[i].lineNumber + ':' +
+        locations[i].columnNumber + ' || ' + line);
+  }
+}
+
+function checkGetBreakableLocations(wasmScriptNr) {
+  InspectorTest.log(
+      'Requesting all breakable locations in wasm script ' + wasmScriptNr);
+  var scriptId = wasmScripts[wasmScriptNr];
+  var source;
+  return Protocol.Debugger.getScriptSource({scriptId: scriptId})
+      .then(msg => source = msg.result.scriptSource)
+      .then(
+          () => Protocol.Debugger.getPossibleBreakpoints(
+              {start: {lineNumber: 0, columnNumber: 0, scriptId: scriptId}}))
+      .then(printFailure)
+      .then(msg => (allBreakableLocations.push(...msg.result.locations), msg))
+      .then(msg => printBreakableLocations(msg, scriptId, source))
+      .then(
+          () => InspectorTest.log(
+              'Requesting breakable locations in lines [0,3)'))
+      .then(() => Protocol.Debugger.getPossibleBreakpoints({
+        start: {lineNumber: 0, columnNumber: 0, scriptId: scriptId},
+        end: {lineNumber: 3, columnNumber: 0, scriptId: scriptId}
+      }))
+      .then(printFailure)
+      .then(msg => printBreakableLocations(msg, scriptId, source))
+      .then(
+          () => InspectorTest.log(
+              'Requesting breakable locations in lines [4,6)'))
+      .then(() => Protocol.Debugger.getPossibleBreakpoints({
+        start: {lineNumber: 4, columnNumber: 0, scriptId: scriptId},
+        end: {lineNumber: 6, columnNumber: 0, scriptId: scriptId}
+      }))
+      .then(printFailure)
+      .then(msg => printBreakableLocations(msg, scriptId, source));
+}
+
+function getBreakableLocationsForAllWasmScripts() {
+  InspectorTest.log('Querying breakable locations for all wasm scripts now...');
+  var promise = Promise.resolve();
+  for (var wasmScriptNr = 0; wasmScriptNr < wasmScripts.length;
+       ++wasmScriptNr) {
+    promise = promise.then(checkGetBreakableLocations.bind(null, wasmScriptNr));
+  }
+  return promise;
+}
+
+function locationMatches(loc1, loc2) {
+  return loc1.scriptId == loc2.scriptId && loc1.lineNumber == loc2.lineNumber &&
+      loc1.columnNumber == loc2.columnNumber;
+}
+
+function locationStr(loc) {
+  return urls[loc.scriptId] + ':' + loc.lineNumber + ':' + loc.columnNumber;
+}
+
+function setBreakpoint(loc) {
+  InspectorTest.log('Setting at ' + locationStr(loc));
+  function check(msg) {
+    if (locationMatches(loc, msg.result.actualLocation)) {
+      InspectorTest.log("Success!");
+    } else {
+      InspectorTest.log("Mismatch!");
+      InspectorTest.logMessage(msg);
+    }
+  }
+  return Protocol.Debugger.setBreakpoint({'location': loc})
+      .then(printFailure)
+      .then(check);
+}
+
+function setAllBreakableLocations() {
+  InspectorTest.log('Setting a breakpoint on each breakable location...');
+  var promise = Promise.resolve();
+  for (var loc of allBreakableLocations) {
+    promise = promise.then(setBreakpoint.bind(null, loc));
+  }
+  return promise;
+}
+
+function removePausedLocation(msg) {
+  var topLocation = msg.params.callFrames[0].location;
+  InspectorTest.log('Stopped at ' + locationStr(topLocation));
+  for (var i = 0; i < allBreakableLocations.length; ++i) {
+    if (locationMatches(topLocation, allBreakableLocations[i])) {
+      allBreakableLocations.splice(i, 1);
+      --i;
+    }
+  }
+}
+
+function waitForAllPauses() {
+  InspectorTest.log('Missing breakpoints: ' + allBreakableLocations.length);
+  if (allBreakableLocations.length == 0) return;
+  return Protocol.Debugger.oncePaused()
+      .then(removePausedLocation)
+      .then(Protocol.Debugger.resume())
+      .then(waitForAllPauses);
+}