[coverage] Block coverage with support for IfStatements

src/interpreter/bytecode-generator.cc

Index: src/interpreter/bytecode-generator.cc
diff --git a/src/interpreter/bytecode-generator.cc b/src/interpreter/bytecode-generator.cc
index b754897e759335c90ea8c4a94555f3d22d3e6a9f..95e1316607f636fc194cf690b9d67b1768a8e127 100644
--- a/src/interpreter/bytecode-generator.cc
+++ b/src/interpreter/bytecode-generator.cc
@@ -772,6 +772,7 @@ BytecodeGenerator::BytecodeGenerator(CompilationInfo* info)
       native_function_literals_(0, info->zone()),
       object_literals_(0, info->zone()),
       array_literals_(0, info->zone()),
+      block_coverage_slots_(0, info->zone()),
       execution_control_(nullptr),
       execution_context_(nullptr),
       execution_result_(nullptr),
@@ -783,6 +784,12 @@ BytecodeGenerator::BytecodeGenerator(CompilationInfo* info)
 
 Handle<BytecodeArray> BytecodeGenerator::FinalizeBytecode(Isolate* isolate) {
   AllocateDeferredConstants(isolate);
+
+  if (is_block_coverage()) {
+    info()->set_coverage_info(
+        isolate->factory()->NewCoverageInfo(block_coverage_slots_));
+  }
+
   if (HasStackOverflow()) return Handle<BytecodeArray>();
   return builder()->ToBytecodeArray(isolate);
 }
@@ -1184,12 +1191,18 @@ void BytecodeGenerator::VisitEmptyStatement(EmptyStatement* stmt) {
 
 void BytecodeGenerator::VisitIfStatement(IfStatement* stmt) {
   builder()->SetStatementPosition(stmt);
+
+  int then_slot = AllocateBlockCoverageSlot(stmt->then_range());
+  int else_slot = AllocateBlockCoverageSlot(stmt->else_range());
+
   if (stmt->condition()->ToBooleanIsTrue()) {
     // Generate then block unconditionally as always true.
+    IncBlockCounter(then_slot);
     Visit(stmt->then_statement());
   } else if (stmt->condition()->ToBooleanIsFalse()) {
     // Generate else block unconditionally if it exists.
     if (stmt->HasElseStatement()) {
+      IncBlockCounter(else_slot);
       Visit(stmt->else_statement());
     }
   } else {
@@ -1202,11 +1215,13 @@ void BytecodeGenerator::VisitIfStatement(IfStatement* stmt) {
                  TestFallthrough::kThen);
 
     then_labels.Bind(builder());
+    IncBlockCounter(then_slot);
     Visit(stmt->then_statement());
 
     if (stmt->HasElseStatement()) {
       builder()->Jump(&end_label);
       else_labels.Bind(builder());
+      IncBlockCounter(else_slot);
       Visit(stmt->else_statement());
     } else {
       else_labels.Bind(builder());
@@ -3899,6 +3914,11 @@ int BytecodeGenerator::feedback_index(FeedbackSlot slot) const {
   return FeedbackVector::GetIndex(slot);
 }
 
+bool BytecodeGenerator::is_block_coverage() const {
+  DCHECK_IMPLIES(info()->is_block_coverage_enabled(), FLAG_block_coverage);
+  return info()->is_block_coverage_enabled();
+}
+
 Runtime::FunctionId BytecodeGenerator::StoreToSuperRuntimeId() {
   return is_strict(language_mode()) ? Runtime::kStoreToSuper_Strict
                                     : Runtime::kStoreToSuper_Sloppy;