Partial ia32 implementation of optimized try/catch (by Kevin Millikin)

src/runtime.cc

Index: src/runtime.cc
diff --git a/src/runtime.cc b/src/runtime.cc
index 0fbd9c2cc082d2b5de218797909b4aac75257a21..0cf8bc9e19167bd1b4ba802e3b4fe97c7d627eff 100644
--- a/src/runtime.cc
+++ b/src/runtime.cc
@@ -1850,10 +1850,12 @@ RUNTIME_FUNCTION(MaybeObject*, Runtime_RegExpConstructResult) {
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_RegExpInitializeObject) {
-  AssertNoAllocation no_alloc;
   ASSERT(args.length() == 5);
   CONVERT_ARG_CHECKED(JSRegExp, regexp, 0);
   CONVERT_ARG_CHECKED(String, source, 1);
+  // The no_alloc scope must begin after the above checks because they can
+  // throw and the throw can allocate to build the message.
+  AssertNoAllocation no_alloc;
   // If source is the empty string we set it to "(?:)" instead as
   // suggested by ECMA-262, 5th, section 15.10.4.1.
   if (source->length() == 0) source = isolate->heap()->query_colon_symbol();
@@ -8817,6 +8819,39 @@ RUNTIME_FUNCTION(MaybeObject*, Runtime_StoreContextSlot) {
 }
 
 
+// Returns the offset in "code" where the code has been patched, as a SMI.
+RUNTIME_FUNCTION(MaybeObject*, Runtime_CatchInOptimizedCode) {
+  HandleScope scope(isolate);
+  ASSERT(args.length() == 1);
+  Code* code = reinterpret_cast<Code*>(args[0]);
+
+  // From the safepoint of the call (i.e., the frame's pc) we can get the
+  // offset of the lazy deoptimization point.
+  DeoptimizationInputData* deopt_data =
+      DeoptimizationInputData::cast(code->deoptimization_data());
+  int deopt_index = isolate->optimized_handler_deopt_index();
+  ASSERT(deopt_index < deopt_data->DeoptCount());
+
+  // Save the code at the lazy deoptimization point off to the side and
+  // patch the lazy deoptimization point with a call to the lazy deopt stub.
+  int patch_size = Deoptimizer::patch_size();
+  Address patch_address =
+      code->instruction_start() + deopt_data->Pc(deopt_index)->value();
+  isolate->set_optimized_handler_patch_buffer(patch_address, patch_size);
+  CodePatcher patcher(patch_address, patch_size);
+  Address deopt_entry =
+      Deoptimizer::GetDeoptimizationEntry(deopt_index, Deoptimizer::LAZY);
+  patcher.masm()->call(deopt_entry, RelocInfo::NONE);
+
+  // Lazy deoptimization expects to find the code in a linked list.
+  isolate->deoptimizer_data()->append_deoptimizing_code(code);
+
+  int frame_pc_offset = isolate->optimized_handler_frame_pc_offset();
+  isolate->clear_optimized_handler_frame_pc_offset();
+  return Smi::FromInt(frame_pc_offset);
+}
+
+
 RUNTIME_FUNCTION(MaybeObject*, Runtime_Throw) {
   HandleScope scope(isolate);
   ASSERT(args.length() == 1);