Implement new stacktrace and deoptimization stress testing flags:

runtime/vm/code_generator.cc

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/code_generator.h"
 
 #include "vm/assembler.h"
 #include "vm/ast.h"
 #include "vm/bigint_operations.h"
 #include "vm/code_patcher.h"
@@ skipping 42 matching lines @@
 DEFINE_FLAG(bool, trace_runtime_calls, false, "Trace runtime calls");
 DEFINE_FLAG(bool, trace_type_checks, false, "Trace runtime type checks.");
 
 DECLARE_FLAG(int, deoptimization_counter_threshold);
 DECLARE_FLAG(bool, enable_type_checks);
 DECLARE_FLAG(bool, report_usage_count);
 
 DEFINE_FLAG(bool, use_osr, true, "Use on-stack replacement.");
 DEFINE_FLAG(bool, trace_osr, false, "Trace attempts at on-stack replacement.");
 
-DECLARE_FLAG(charp, deoptimize_filter);
+DEFINE_FLAG(int, stacktrace_every, 0,
+            "Compute debugger stacktrace on every N stack overflow checks");
+DEFINE_FLAG(charp, stacktrace_filter, NULL,
+            "Compute stacktrace in named function on stack overflow checks");
+DEFINE_FLAG(int, deoptimize_every, 0,
+            "Deoptimize on every N stack overflow checks");
+DEFINE_FLAG(charp, deoptimize_filter, NULL,
+            "Deoptimize in named function on stack overflow checks");
 
 
 DEFINE_RUNTIME_ENTRY(TraceFunctionEntry, 1) {
   const Function& function = Function::CheckedHandle(arguments.ArgAt(0));
   const String& function_name = String::Handle(function.name());
   const String& class_name =
       String::Handle(Class::Handle(function.Owner()).Name());
   OS::PrintErr("> Entering '%s.%s'\n",
       class_name.ToCString(), function_name.ToCString());
 }
@@ skipping 941 matching lines @@
   return true;
 }
 
 
 DEFINE_RUNTIME_ENTRY(StackOverflow, 0) {
 #if defined(USING_SIMULATOR)
   uword stack_pos = Simulator::Current()->get_register(SPREG);
 #else
   uword stack_pos = reinterpret_cast<uword>(&arguments);
 #endif
+  // Always clear the stack overflow flags.  They are meant for this
+  // particular stack overflow runtime call and are not meant to
+  // persist.
+  uword stack_overflow_flags = isolate->GetAndClearStackOverflowFlags();
 
   // If an interrupt happens at the same time as a stack overflow, we
-  // process the stack overflow first.
+  // process the stack overflow now and leave the interrupt for next
+  // time.
   if (stack_pos < isolate->saved_stack_limit()) {
     // Use the preallocated stack overflow exception to avoid calling
     // into dart code.
     const Instance& exception =
         Instance::Handle(isolate->object_store()->stack_overflow());
     Exceptions::Throw(exception);
     UNREACHABLE();
   }
 
   uword interrupt_bits = isolate->GetAndClearInterrupts();
@@ skipping 20 matching lines @@
       }
     }
   }
   if (interrupt_bits & Isolate::kVmStatusInterrupt) {
     Dart_IsolateInterruptCallback callback = isolate->VmStatsCallback();
     if (callback) {
       (*callback)();
     }
   }
 
-  if (FLAG_use_osr && (interrupt_bits == 0)) {
+  if (stack_overflow_flags & Isolate::kOsrRequest) {

[Cutch, 2014/04/07 23:19:57]

(stack_overflow_flags & Isolate::kOsrRequest) != 0

[turnidge, 2014/04/09 17:22:02]

Done.

+    ASSERT(FLAG_use_osr);
     DartFrameIterator iterator;
     StackFrame* frame = iterator.NextFrame();
     ASSERT(frame != NULL);
     const Code& code = Code::ZoneHandle(frame->LookupDartCode());
     ASSERT(!code.IsNull());
     const Function& function = Function::Handle(code.function());
     ASSERT(!function.IsNull());
     // Since the code is referenced from the frame and the ZoneHandle,
     // it cannot have been removed from the function.
     ASSERT(function.HasCode());
@@ skipping 26 matching lines @@
       // The OSR code does not work for calling the function, so restore the
       // unoptimized code.  Patch the stack frame to return into the OSR
       // code.
       uword optimized_entry =
           Instructions::Handle(optimized_code.instructions()).EntryPoint();
       function.AttachCode(original_code);
       frame->set_pc(optimized_entry);
     }
   }
 
-  if (FLAG_deoptimize_filter != NULL) {
+  // The following code is used to stress test deoptimization and
+  // debugger stack tracing.
+  bool do_deopt = false;
+  bool do_stacktrace = false;
+  if (FLAG_deoptimize_every > 0 ||
+      FLAG_stacktrace_every > 0) {
+    // TODO(turnidge): To make --deoptimize_every and
+    // --stacktrace-every faster we could move this increment/test to
+    // the generated code.
+    int32_t count = isolate->IncrementAndGetStackOverflowCount();
+    if (FLAG_deoptimize_every > 0 &&
+        (count % FLAG_deoptimize_every) == 0) {
+      do_deopt = true;
+    }
+    if (FLAG_stacktrace_every > 0 &&
+        (count % FLAG_stacktrace_every) == 0) {
+      do_stacktrace = true;
+    }
+  }
+  if (FLAG_deoptimize_filter != NULL ||
+      FLAG_stacktrace_filter != NULL) {
     DartFrameIterator iterator;
     StackFrame* frame = iterator.NextFrame();
     ASSERT(frame != NULL);
     const Code& code = Code::Handle(frame->LookupDartCode());
     ASSERT(!code.IsNull());
-    if (code.is_optimized()) {
-      const Function& function = Function::Handle(code.function());
-      ASSERT(!function.IsNull());
-      if (strstr(function.ToFullyQualifiedCString(),
-                 FLAG_deoptimize_filter) != NULL) {
-        if (FLAG_trace_deoptimization || FLAG_trace_deoptimization_verbose) {
-          OS::PrintErr("*** Forcing deoptimization (%s)\n",
-                       function.ToFullyQualifiedCString());
-          // TODO(turnidge): Consider changing to DeoptimizeAt for
-          // just the top frame.
-          DeoptimizeAll();
-        }
+    const Function& function = Function::Handle(code.function());
+    ASSERT(!function.IsNull());
+    const char* function_name = function.ToFullyQualifiedCString();
+    ASSERT(function_name != NULL);
+    if (code.is_optimized() &&
+        FLAG_deoptimize_filter != NULL &&
+        strstr(function_name, FLAG_deoptimize_filter) != NULL) {
+      OS::PrintErr("*** Forcing deoptimization (%s)\n",
+                   function.ToFullyQualifiedCString());
+      do_deopt = true;
+    }
+    if (FLAG_stacktrace_filter != NULL &&
+        strstr(function_name, FLAG_stacktrace_filter) != NULL) {
+      OS::PrintErr("*** Computing stacktrace (%s)\n",
+                   function.ToFullyQualifiedCString());
+      do_stacktrace = true;
+    }
+  }
+  if (do_deopt) {
+    // TODO(turnidge): Consider using DeoptimizeAt instead.
+    DeoptimizeAll();
+  }
+  if (do_stacktrace) {
+    String& var_name = String::Handle();
+    Instance& var_value = Instance::Handle();
+    DebuggerStackTrace* stack = isolate->debugger()->StackTrace();
+    intptr_t num_frames = stack->Length();
+    for (intptr_t i = 0; i < num_frames; i++) {
+      ActivationFrame* frame = stack->FrameAt(i);
+      const int num_vars = frame->NumLocalVariables();
+      intptr_t unused;
+      for (intptr_t v = 0; v < num_vars; v++) {
+        frame->VariableAt(v, &var_name, &unused, &unused, &var_value);
       }
     }
   }
 }
 
 
 DEFINE_RUNTIME_ENTRY(TraceICCall, 2) {
   const ICData& ic_data = ICData::CheckedHandle(arguments.ArgAt(0));
   const Function& function = Function::CheckedHandle(arguments.ArgAt(1));
   DartFrameIterator iterator;
@@ skipping 315 matching lines @@
 // of the given value.
 //   Arg0: Field object;
 //   Arg1: Value that is being stored.
 DEFINE_RUNTIME_ENTRY(UpdateFieldCid, 2) {
   const Field& field = Field::CheckedHandle(arguments.ArgAt(0));
   const Object& value = Object::Handle(arguments.ArgAt(1));
   field.UpdateGuardedCidAndLength(value);
 }
 
 }  // namespace dart