[runtime] Add --trace-interrupts flag

Add a flag which traces which interrupts are being handled by the
StackGuard's HandleInterrupts function.

Change-Id: I18fcf58b03cf6c255d7457d8a55b0a0dadb00931
Reviewed-on: https://chromium-review.googlesource.com/649530
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#47828}

src/execution.cc

@@ -466,32 +466,73 @@ Object* StackGuard::HandleInterrupts() {
     isolate_->heap()->MonotonicallyIncreasingTimeInMs();
   }
 
+  bool any_interrupt_handled = false;
+  if (FLAG_trace_interrupts) {
+    PrintF("[Handling interrupts: ");
+  }
+
   if (CheckAndClearInterrupt(GC_REQUEST)) {
+    if (FLAG_trace_interrupts) {
+      PrintF("GC_REQUEST");
+      any_interrupt_handled = true;
+    }
     isolate_->heap()->HandleGCRequest();
   }
 
   if (CheckDebugBreak()) {
+    if (FLAG_trace_interrupts) {
+      if (any_interrupt_handled) PrintF(", ");
+      PrintF("DEBUG_BREAK");
+      any_interrupt_handled = true;
+    }
     isolate_->debug()->HandleDebugBreak(kIgnoreIfTopFrameBlackboxed);
   }
 
   if (CheckAndClearInterrupt(TERMINATE_EXECUTION)) {
+    if (FLAG_trace_interrupts) {
+      if (any_interrupt_handled) PrintF(", ");
+      PrintF("TERMINATE_EXECUTION");
+      any_interrupt_handled = true;
+    }
     return isolate_->TerminateExecution();
   }
 
   if (CheckAndClearInterrupt(DEOPT_MARKED_ALLOCATION_SITES)) {
+    if (FLAG_trace_interrupts) {
+      if (any_interrupt_handled) PrintF(", ");
+      PrintF("DEOPT_MARKED_ALLOCATION_SITES");
+      any_interrupt_handled = true;
+    }
     isolate_->heap()->DeoptMarkedAllocationSites();
   }
 
   if (CheckAndClearInterrupt(INSTALL_CODE)) {
+    if (FLAG_trace_interrupts) {
+      if (any_interrupt_handled) PrintF(", ");
+      PrintF("INSTALL_CODE");
+      any_interrupt_handled = true;
+    }
     DCHECK(isolate_->concurrent_recompilation_enabled());
     isolate_->optimizing_compile_dispatcher()->InstallOptimizedFunctions();
   }
 
   if (CheckAndClearInterrupt(API_INTERRUPT)) {
+    if (FLAG_trace_interrupts) {
+      if (any_interrupt_handled) PrintF(", ");
+      PrintF("API_INTERRUPT");
+      any_interrupt_handled = true;
+    }
     // Callbacks must be invoked outside of ExecusionAccess lock.
     isolate_->InvokeApiInterruptCallbacks();
   }
 
+  if (FLAG_trace_interrupts) {
+    if (!any_interrupt_handled) {
+      PrintF("No interrupt flags set");
+    }
+    PrintF("]\n");
+  }
+
   isolate_->counters()->stack_interrupts()->Increment();
   isolate_->counters()->runtime_profiler_ticks()->Increment();
   isolate_->runtime_profiler()->MarkCandidatesForOptimization();

src/flag-definitions.h

@@ -546,9 +546,6 @@ DEFINE_INT(generic_ic_threshold, 30,
            "max percentage of megamorphic/generic ICs to allow optimization")
 DEFINE_INT(self_opt_count, 130, "call count before self-optimization")
 
-DEFINE_BOOL(trace_opt_verbose, false, "extra verbose compilation tracing")
-DEFINE_IMPLICATION(trace_opt_verbose, trace_opt)
-
 // Garbage collections flags.
 DEFINE_INT(min_semi_space_size, 0,
            "min size of a semi-space (in MBytes), the new space consists of two"
@@ -745,14 +742,17 @@ DEFINE_BOOL(trace, false, "trace function calls")
 // codegen.cc
 DEFINE_BOOL(lazy, true, "use lazy compilation")
 DEFINE_BOOL(trace_opt, false, "trace lazy optimization")
+DEFINE_BOOL(trace_opt_verbose, false, "extra verbose compilation tracing")
+DEFINE_IMPLICATION(trace_opt_verbose, trace_opt)
 DEFINE_BOOL(trace_opt_stats, false, "trace lazy optimization statistics")
+DEFINE_BOOL(trace_deopt, false, "trace optimize function deoptimization")
 DEFINE_BOOL(trace_file_names, false,
             "include file names in trace-opt/trace-deopt output")
+DEFINE_BOOL(trace_interrupts, false, "trace interrupts when they are handled")
 DEFINE_BOOL(opt, true, "use adaptive optimizations")
 DEFINE_BOOL(always_opt, false, "always try to optimize functions")
 DEFINE_BOOL(always_osr, false, "always try to OSR functions")
 DEFINE_BOOL(prepare_always_opt, false, "prepare for turning on always opt")
-DEFINE_BOOL(trace_deopt, false, "trace optimize function deoptimization")
 
 DEFINE_BOOL(serialize_toplevel, true, "enable caching of toplevel scripts")
 DEFINE_BOOL(serialize_eager, false, "compile eagerly when caching scripts")