[vm/bytecode] Preliminary support for new language features in bytecode

Issue: #36214
Issue: #36218

Change-Id: I39149b82cb93c1cb87c64cf9c41c56b753bba13a
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/98400
Reviewed-by: Aart Bik <[email protected]>
Commit-Queue: Alexander Markov <[email protected]>
Auto-Submit: Alexander Markov <[email protected]>

Author: alexmarkov

pkg/vm/lib/bytecode/gen_bytecode.dart

@@ -2701,6 +2701,14 @@ class BytecodeGenerator extends RecursiveVisitor<Null> {
     asm.bind(done);
   }
 
+  @override
+  visitBlockExpression(BlockExpression node) {
+    _enterScope(node);
+    _generateNodeList(node.body.statements);
+    _generateNode(node.value);
+    _leaveScope();
+  }
+
   @override
   visitBreakStatement(BreakStatement node) {
     final targetLabel = labeledStatements[node.target] ??

pkg/vm/lib/bytecode/local_vars.dart

@@ -597,6 +597,16 @@ class _ScopeBuilder extends RecursiveVisitor<Null> {
     _visitWithScope(node);
   }
 
+  @override
+  visitBlockExpression(BlockExpression node) {
+    // Not using _visitWithScope as Block inside BlockExpression does not have
+    // a scope.
+    _enterScope(node);
+    visitList(node.body.statements, this);
+    node.value.accept(this);
+    _leaveScope();
+  }
+
   @override
   visitAssertBlock(AssertBlock node) {
     _visitWithScope(node);
@@ -1036,6 +1046,15 @@ class _Allocator extends RecursiveVisitor<Null> {
     _visit(node, scope: true);
   }
 
+  @override
+  visitBlockExpression(BlockExpression node) {
+    // Not using _visit as Block inside BlockExpression does not have a scope.
+    _enterScope(node);
+    visitList(node.body.statements, this);
+    node.value.accept(this);
+    _leaveScope();
+  }
+
   @override
   visitAssertBlock(AssertBlock node) {
     _visit(node, scope: true);

runtime/vm/compiler/frontend/bytecode_flow_graph_builder.cc

@@ -327,12 +327,6 @@ void BytecodeFlowGraphBuilder::PropagateStackState(intptr_t target_pc) {
     return;
   }
 
-  // Stack state propagation is supported for forward branches only.
-  // Bytecode generation guarantees that expression stack is empty between
-  // statements and backward jumps are only used to transfer control between
-  // statements (e.g. in loop and continue statements).
-  RELEASE_ASSERT(target_pc > pc_);
-
   Value* current_stack = B->stack_;
   Value* target_stack = stack_states_.Lookup(target_pc);
 
@@ -341,6 +335,8 @@ void BytecodeFlowGraphBuilder::PropagateStackState(intptr_t target_pc) {
     // all incoming branches.
     RELEASE_ASSERT(target_stack == current_stack);
   } else {
+    // Stack state propagation is supported for forward branches only.
+    RELEASE_ASSERT(target_pc > pc_);
     stack_states_.Insert(target_pc, current_stack);
   }
 }
@@ -666,11 +662,15 @@ void BytecodeFlowGraphBuilder::BuildCheckStack() {
   }
   const intptr_t loop_depth = DecodeOperandA().value();
   if (loop_depth == 0) {
+    ASSERT(IsStackEmpty());
     code_ += B->CheckStackOverflowInPrologue(position_);
   } else {
-    code_ += B->CheckStackOverflow(position_, loop_depth);
+    // Avoid OSR points inside block-expressions.
+    // TODO(ajcbik): make sure OSR works inside BE too.
+    if (!IsStackEmpty()) {
+      code_ += B->CheckStackOverflow(position_, loop_depth);
+    }
   }
-  ASSERT(IsStackEmpty());
 }
 
 void BytecodeFlowGraphBuilder::BuildPushConstant() {
@@ -1824,7 +1824,10 @@ FlowGraph* BytecodeFlowGraphBuilder::BuildGraph() {
     if (join != nullptr) {
       Value* stack_state = stack_states_.Lookup(pc_);
       if (code_.is_open()) {
-        ASSERT((stack_state == nullptr) || (stack_state == B->stack_));
+        if (stack_state != B->stack_) {
+          ASSERT(stack_state == nullptr);
+          stack_states_.Insert(pc_, B->stack_);
+        }
         code_ += B->Goto(join);
       } else {
         ASSERT(IsStackEmpty());

tests/language_2/language_2_kernel.status

@@ -37,7 +37,6 @@ const_map4_test: RuntimeError
 const_nested_test: RuntimeError
 const_string_test: RuntimeError
 constructor12_test: RuntimeError
-control_flow_collections/*: Skip
 covariant_subtyping_test: RuntimeError
 ct_const_test: RuntimeError
 cyclic_type2_test: CompileTimeError
@@ -146,11 +145,7 @@ web_int_literals_test/*: SkipByDesign # Test applies only to JavaScript targets
 mixin_method_override_test/G5: Skip # Issue 34354
 private_method_tearoff_test: RuntimeError
 
-[ $compiler == dartk ]
-control_flow_collections/*: Skip
-
 [ $compiler == dartkp ]
-control_flow_collections/*: Skip
 covariant_subtyping_test: RuntimeError
 generic_no_such_method_dispatcher_test: RuntimeError # Issue 31424
 spread_collections/await_test: CompileTimeError
@@ -561,19 +556,8 @@ async_star_test/04: Pass, RuntimeError # Please triage
 compile_time_constant_o_test/01: Pass
 compile_time_constant_o_test/02: Pass
 const_dynamic_type_literal_test/02: Pass
-control_flow_collections/*: Skip
 map_literal3_test/01: Pass
 map_literal3_test/02: Pass
-spread_collections/await_test: CompileTimeError
-spread_collections/const_test: CompileTimeError
-spread_collections/inference_test: CompileTimeError
-spread_collections/map_set_ambiguity_test: CompileTimeError
-spread_collections/spread_test: CompileTimeError
-spread_collections/syntax_test: CompileTimeError
-spread_collections/type_error_test/00: DartkCrash
-spread_collections/type_error_test/02: DartkCrash
-spread_collections/type_error_test/03: DartkCrash
-spread_collections/type_error_test/05: DartkCrash
 vm/bool_check_stack_traces_test/02: Pass
 vm/causal_async_exception_stack2_test: RuntimeError # Please triage
 vm/causal_async_exception_stack_test: RuntimeError # Please triage
@@ -2181,6 +2165,9 @@ async_star_test/05: Skip # Timeout
 async_star_test/none: Skip # Timeout
 type_constants_test/none: Skip # Deferred libraries and hot reload.
 
+[ $compiler == app_jitk || $compiler == dartk || $compiler == dartkb || $compiler == dartkp ]
+control_flow_collections/*: Skip
+
 [ $compiler == dartk || $compiler == dartkb || $compiler == dartkp ]
 generic_function_bounds_test: RuntimeError # Issue 32076