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[interpreter, debugger] replace bytecode on-stack for debugging.

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R=mcilroy@chromium.org
BUG=v8:4690
LOG=N

Review URL: https://codereview.chromium.org/1723803004

Cr-Commit-Position: refs/heads/master@{#34210}
This commit is contained in:
yangguo 2016-02-23 05:10:45 -08:00 committed by Commit bot
parent be65129e65
commit 72ba53b19a
2 changed files with 79 additions and 10 deletions
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41
src/debug/debug.cc
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@ -1240,13 +1240,18 @@ class RedirectActiveFunctions : public ThreadVisitor {
for (JavaScriptFrameIterator it(isolate, top); !it.done(); it.Advance()) {
JavaScriptFrame* frame = it.frame();
JSFunction* function = frame->function();
if (frame->is_interpreted()) {
// TODO(yangguo): replace dispatch table for activated frames.
continue;
}
if (frame->is_optimized()) continue;
if (!function->Inlines(shared_)) continue;
if (frame->is_interpreted()) {
InterpretedFrame* interpreted_frame =
reinterpret_cast<InterpretedFrame*>(frame);
BytecodeArray* debug_copy =
shared_->GetDebugInfo()->abstract_code()->GetBytecodeArray();
interpreted_frame->PatchBytecodeArray(debug_copy);
continue;
}
Code* frame_code = frame->LookupCode();
DCHECK(frame_code->kind() == Code::FUNCTION);
if (frame_code->has_debug_break_slots()) continue;
@ -1304,11 +1309,15 @@ bool Debug::PrepareFunctionForBreakPoints(Handle<SharedFunctionInfo> shared) {
// Make sure we abort incremental marking.
isolate_->heap()->CollectAllGarbage(Heap::kMakeHeapIterableMask,
"prepare for break points");
bool is_interpreted = shared->HasBytecodeArray();
{
// TODO(yangguo): with bytecode, we still walk the heap to find all
// optimized code for the function to deoptimize. We can probably be
// smarter here and avoid the heap walk.
HeapIterator iterator(isolate_->heap());
HeapObject* obj;
bool include_generators = shared->is_generator();
bool include_generators = !is_interpreted && shared->is_generator();
while ((obj = iterator.next())) {
if (obj->IsJSFunction()) {
@ -1317,6 +1326,7 @@ bool Debug::PrepareFunctionForBreakPoints(Handle<SharedFunctionInfo> shared) {
if (function->code()->kind() == Code::OPTIMIZED_FUNCTION) {
Deoptimizer::DeoptimizeFunction(function);
}
if (is_interpreted) continue;
if (function->shared() == *shared) functions.Add(handle(function));
} else if (include_generators && obj->IsJSGeneratorObject()) {
JSGeneratorObject* generator_obj = JSGeneratorObject::cast(obj);
@ -1332,7 +1342,12 @@ bool Debug::PrepareFunctionForBreakPoints(Handle<SharedFunctionInfo> shared) {
}
}
if (!shared->HasDebugCode()) {
// We do not need to replace code to debug bytecode.
DCHECK(!is_interpreted || functions.length() == 0);
DCHECK(!is_interpreted || suspended_generators.length() == 0);
// We do not need to recompile to debug bytecode.
if (!is_interpreted && !shared->HasDebugCode()) {
DCHECK(functions.length() > 0);
if (!Compiler::CompileDebugCode(functions.first())) return false;
}
@ -1503,10 +1518,16 @@ bool Debug::EnsureDebugInfo(Handle<SharedFunctionInfo> shared,
return false;
}
if (!PrepareFunctionForBreakPoints(shared)) return false;
CreateDebugInfo(shared);
if (shared->HasBytecodeArray()) {
// To prepare bytecode for debugging, we already need to have the debug
// info (containing the debug copy) upfront, but since we do not recompile,
// preparing for break points cannot fail.
CreateDebugInfo(shared);
CHECK(PrepareFunctionForBreakPoints(shared));
} else {
if (!PrepareFunctionForBreakPoints(shared)) return false;
CreateDebugInfo(shared);
}
return true;
}

48
test/mjsunit/ignition/debug-break-on-stack.js Normal file
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@ -0,0 +1,48 @@
// 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-debug-as debug
var Debug = debug.Debug;
var break_count = 0;
var exception = null;
function listener(event, exec_state, event_data, data) {
if (event != Debug.DebugEvent.Break) return;
try {
break_count++;
var line = exec_state.frame(0).sourceLineText();
print(line);
assertTrue(line.indexOf(`B${break_count}`) > 0);
} catch (e) {
exception = e;
}
}
function g() {
setbreaks();
throw 1; // B1
}
function f() {
try {
g();
} catch (e) {}
return 2; // B2
}
function setbreaks() {
Debug.setListener(listener);
Debug.setBreakPoint(g, 2, 0);
Debug.setBreakPoint(f, 4, 0);
}
f();
assertEquals(2, break_count);
assertNull(exception);
Debug.setListener(null);