Emit DebugHooks uniformly with pause locations instead of having separate pause locations and op_debug emits
https://bugs.webkit.org/show_bug.cgi?id=162809
Reviewed by Geoffrey Garen.
Source/JavaScriptCore:
Change how BytecodeGeneration emits debug hooks to be more consistent.
Previously most nodes individually generated their own debug hook
and we asserted that it matched a breakpoint location identified
by the parser. This could get out of sync, or nodes could forget to
emit debug hooks expected by the parser.
With this change, we always check and emit a debug hook for any
node. The default behavior is for BytecodeGenerator::emitNode
to emit the debug hook when emitting the node itself. This covers
the majority of cases (statements).
There are a few exceptions where we continue to need to customize
emitting debug hooks:
- Nodes with emitBytecodeInConditionContext
- non-Expression nodes customize how they emit their children
- constants conditions may emit nothing, but we had recorded a breakpoint location so emit a debug hook
- always emit one debug hook in case we recorded a breakpoint location, but avoid emitting multiple
in nodes which may call up to the ExpressionNode::emitBytecodeInConditionContext base impl.
- Specialized Debug Hooks
- such as hooks for Program start/end, debugger statements, etc.
- Debug Hooks in for..of / for..in that don't correspond to re-emitting nodes
- such as pausing on the assignment expression inside these loops
The majority of nodes no longer have custom emits.
- bytecompiler/BytecodeGenerator.h:
(JSC::BytecodeGenerator::emitNodeInTailPosition):
(JSC::BytecodeGenerator::emitNodeInConditionContext):
- bytecompiler/BytecodeGenerator.cpp:
(JSC::BytecodeGenerator::emitDebugHook):
(JSC::BytecodeGenerator::emitEnumeration):
By default, when emitting a node check if we should also emit an op_debug for it.
This default DebugHook is WillExecuteStatement, which is a normal pause point.
- bytecompiler/NodesCodegen.cpp:
(JSC::ConstantNode::emitBytecodeInConditionContext):
(JSC::LogicalNotNode::emitBytecodeInConditionContext):
(JSC::BinaryOpNode::emitBytecodeInConditionContext):
(JSC::LogicalOpNode::emitBytecodeInConditionContext):
The parser would have generated a pause location for these conditions
no matter what constant folding and re-writing these nodes may perform.
So, when emitting these nodes in condition context check if they need
emit their own debug hook.
(JSC::EmptyStatementNode::emitBytecode):
(JSC::ExprStatementNode::emitBytecode):
(JSC::DeclarationStatement::emitBytecode):
(JSC::IfElseNode::emitBytecode):
(JSC::DoWhileNode::emitBytecode):
(JSC::WhileNode::emitBytecode):
(JSC::ForNode::emitBytecode):
(JSC::ContinueNode::emitBytecode):
(JSC::BreakNode::emitBytecode):
(JSC::ReturnNode::emitBytecode):
(JSC::WithNode::emitBytecode):
(JSC::SwitchNode::emitBytecode):
(JSC::ThrowNode::emitBytecode):
No longer need to custom emit debug hooks. The default emitNode will handle these.
(JSC::ForInNode::emitBytecode):
Include extra debug hooks the user expects to return back to the assignment
expression in the loop header before starting the body again. The same is done
for for..of with emitEnumeration.
(JSC::ASTBuilder::createExportDefaultDeclaration):
(JSC::ASTBuilder::createExportLocalDeclaration):
These are no longer needed to fake-satisfy assertions. We never wanted to
emit debug hooks for these inner statements because the export statement
will already have the debug hooks.
(JSC::ASTBuilder::createForInLoop):
(JSC::ASTBuilder::createForOfLoop):
Include the correct location where the declaration starts.
(JSC::ASTBuilder::breakpointLocation):
Simplify to a general implementation for Node.
(JSC::SyntaxChecker::createForInLoop):
(JSC::SyntaxChecker::createForOfLoop):
Ignore the new extra parameter.
(JSC::Node::needsDebugHook):
(JSC::Node::setNeedsDebugHook):
(JSC::ExpressionNode::needsDebugHook): Deleted.
(JSC::ExpressionNode::setNeedsDebugHook): Deleted.
(JSC::StatementNode::isEmptyStatement): Deleted.
(JSC::StatementNode::needsDebugHook): Deleted.
(JSC::StatementNode::setNeedsDebugHook): Deleted.
Move debug hook logic into the base Node class.
(JSC::StatementNode::isDebuggerStatement):
Provide a way to distinguish a debugger statement.
(JSC::Parser<LexerType>::parseForStatement):
Provide the location before the declaration starts.
Source/WebInspectorUI:
- UserInterface/Views/SourceCodeTextEditor.js:
(WebInspector.SourceCodeTextEditor.prototype.textEditorExecutionHighlightRange):
When pausing on the variable assignment inside for..of and for..in don't just
highlight "var foo" but include the right hand side "var foo in ..." or
"var foo of ...".
LayoutTests:
- inspector/debugger/stepping/stepping-control-flow-expected.txt:
- inspector/debugger/stepping/stepping-control-flow.html:
Add new tests for stepping through conditional expressions with constants,
logical operations, binary operations, and unary negations.
- inspector/debugger/stepping/stepping-loops-expected.txt:
- inspector/debugger/stepping/stepping-loops.html:
Update tests for changes in stepping behavior in for loops.
