[interpreter] Implement OSR graph construction from bytecode.

src/compiler.cc

Index: src/compiler.cc
diff --git a/src/compiler.cc b/src/compiler.cc
index dbefcfebfb72adcac99e4e7efe3d67f44aaa47a4..5dc97671435c9e35667ec1adfc159849066ce78b 100644
--- a/src/compiler.cc
+++ b/src/compiler.cc
@@ -587,6 +587,10 @@ void InsertCodeIntoOptimizedCodeMap(CompilationInfo* info) {
   // Frame specialization implies function context specialization.
   DCHECK(!info->is_frame_specializing());
 
+  // TODO(4764): When compiling for OSR from bytecode, BailoutId might derive
+  // from bytecode offset and overlap with actual BailoutId. No caching!
+  if (info->is_osr() && info->is_optimizing_from_bytecode()) return;
+
   // Cache optimized context-specific code.
   Handle<JSFunction> function = info->closure();
   Handle<SharedFunctionInfo> shared(function->shared());
@@ -747,13 +751,18 @@ MaybeHandle<Code> GetOptimizedCode(Handle<JSFunction> function,
   Isolate* isolate = function->GetIsolate();
   Handle<SharedFunctionInfo> shared(function->shared(), isolate);
 
-  // TODO(4764): Remove this guard once OSR graph construction works.
-  if (!osr_ast_id.IsNone() && osr_frame->is_interpreted()) {
-    return MaybeHandle<Code>();
-  }
+  bool ignition_osr = osr_frame && osr_frame->is_interpreted();
+  DCHECK_IMPLIES(ignition_osr, !osr_ast_id.IsNone());
+  DCHECK_IMPLIES(ignition_osr, FLAG_ignition_osr);
+
+  // Flag combination --ignition-osr --no-turbo-from-bytecode is unsupported.
+  if (ignition_osr && !FLAG_turbo_from_bytecode) return MaybeHandle<Code>();
 
   Handle<Code> cached_code;
-  if (GetCodeFromOptimizedCodeMap(function, osr_ast_id)
+  // TODO(4764): When compiling for OSR from bytecode, BailoutId might derive
+  // from bytecode offset and overlap with actual BailoutId. No lookup!
+  if (!ignition_osr &&
+      GetCodeFromOptimizedCodeMap(function, osr_ast_id)
           .ToHandle(&cached_code)) {
     if (FLAG_trace_opt) {
       PrintF("[found optimized code for ");
@@ -774,7 +783,7 @@ MaybeHandle<Code> GetOptimizedCode(Handle<JSFunction> function,
   VMState<COMPILER> state(isolate);
   DCHECK(!isolate->has_pending_exception());
   PostponeInterruptsScope postpone(isolate);
-  bool use_turbofan = UseTurboFan(shared);
+  bool use_turbofan = UseTurboFan(shared) || ignition_osr;
   std::unique_ptr<CompilationJob> job(
       use_turbofan ? compiler::Pipeline::NewCompilationJob(function)
                    : new HCompilationJob(function));