[coverage] Block coverage with support for IfStatements

src/runtime/runtime-debug.cc

Index: src/runtime/runtime-debug.cc
diff --git a/src/runtime/runtime-debug.cc b/src/runtime/runtime-debug.cc
index b65757b2de4957df4070fb4dee50359b995fec1b..cbc46caf24661664b0659a019788100324f48c21 100644
--- a/src/runtime/runtime-debug.cc
+++ b/src/runtime/runtime-debug.cc
@@ -1965,5 +1965,28 @@ RUNTIME_FUNCTION(Runtime_DebugTogglePreciseCoverage) {
   return isolate->heap()->undefined_value();
 }
 
+RUNTIME_FUNCTION(Runtime_DebugToggleBlockCoverage) {
+  SealHandleScope shs(isolate);
+  CONVERT_BOOLEAN_ARG_CHECKED(enable, 0);
+  Coverage::SelectMode(isolate, enable ? debug::Coverage::kBlockBinary
+                                       : debug::Coverage::kBestEffort);
+  return isolate->heap()->undefined_value();
+}
+
+RUNTIME_FUNCTION(Runtime_IncBlockCounter) {
+  HandleScope scope(isolate);
+  DCHECK_EQ(2, args.length());
+  CONVERT_ARG_HANDLE_CHECKED(FeedbackVector, vector, 0);

[rmcilroy, 2017/05/18 14:17:59]

Unused?

[jgruber, 2017/05/22 09:43:32]

The vector is needed to get to the SFI below.

[rmcilroy, 2017/05/22 11:08:46]

Sorry missed this. It's more normal to get the SFI from the JSFunction. Could
you do this instead (you can get it in interpreter-generator with
LoadRegister(Register::function_closure())

[jgruber, 2017/05/22 11:10:08]

Sure, will do.

+  CONVERT_SMI_ARG_CHECKED(slot_index, 1);

[rmcilroy, 2017/05/18 14:17:59]

coverage_array_slot

[jgruber, 2017/05/22 09:43:32]

Done.

+
+  DCHECK(FLAG_block_coverage);
+
+  SharedFunctionInfo* shared = vector->shared_function_info();
+  CoverageInfo* coverage_info = CoverageInfo::cast(shared->coverage_info());
+  coverage_info->IncrementBlockCount(slot_index);
+
+  return isolate->heap()->undefined_value();
+}
+
 }  // namespace internal
 }  // namespace v8