Stop attaching try_index to individual instructions put it at block entry instead.

runtime/vm/intermediate_language.cc

Index: runtime/vm/intermediate_language.cc
diff --git a/runtime/vm/intermediate_language.cc b/runtime/vm/intermediate_language.cc
index 7518fcb256fc5fd8d2c5b28c5a1a6f28d5451cd2..b9fd0bc5cf15d2501f7a767f4677c7127b648ff0 100644
--- a/runtime/vm/intermediate_language.cc
+++ b/runtime/vm/intermediate_language.cc
@@ -1191,8 +1191,8 @@ void JoinEntryInstr::PrepareEntry(FlowGraphCompiler* compiler) {
 
 void TargetEntryInstr::PrepareEntry(FlowGraphCompiler* compiler) {
   __ Bind(compiler->GetBlockLabel(this));
-  if (HasTryIndex()) {
-    compiler->AddExceptionHandler(try_index(),
+  if (IsCatchEntry()) {
+    compiler->AddExceptionHandler(catch_try_index(),
                                   compiler->assembler()->CodeSize());
   }
   if (HasParallelMove()) {
@@ -1210,7 +1210,6 @@ LocationSummary* ThrowInstr::MakeLocationSummary() const {
 void ThrowInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
   compiler->GenerateCallRuntime(deopt_id(),
                                 token_pos(),
-                                try_index(),
                                 kThrowRuntimeEntry,
                                 locs());
   __ int3();
@@ -1225,7 +1224,6 @@ LocationSummary* ReThrowInstr::MakeLocationSummary() const {
 void ReThrowInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
   compiler->GenerateCallRuntime(deopt_id(),
                                 token_pos(),
-                                try_index(),
                                 kReThrowRuntimeEntry,
                                 locs());
   __ int3();
@@ -1362,7 +1360,6 @@ void ClosureCallComp::EmitNativeCode(FlowGraphCompiler* compiler) {
   __ LoadObject(temp_reg, arguments_descriptor);
 
   compiler->GenerateCall(token_pos(),
-                         try_index(),
                          &StubCode::CallClosureFunctionLabel(),
                          PcDescriptors::kOther,
                          locs());
@@ -1378,11 +1375,9 @@ LocationSummary* InstanceCallComp::MakeLocationSummary() const {
 void InstanceCallComp::EmitNativeCode(FlowGraphCompiler* compiler) {
   compiler->AddCurrentDescriptor(PcDescriptors::kDeopt,
                                  deopt_id(),
-                                 token_pos(),
-                                 try_index());
+                                 token_pos());
   compiler->GenerateInstanceCall(deopt_id(),
                                  token_pos(),
-                                 try_index(),
                                  function_name(),
                                  ArgumentCount(),
                                  argument_names(),
@@ -1404,7 +1399,6 @@ void StaticCallComp::EmitNativeCode(FlowGraphCompiler* compiler) {
   }
   compiler->GenerateStaticCall(deopt_id(),
                                token_pos(),
-                               try_index(),
                                function(),
                                ArgumentCount(),
                                argument_names(),
@@ -1417,7 +1411,6 @@ void AssertAssignableComp::EmitNativeCode(FlowGraphCompiler* compiler) {
   if (!is_eliminated()) {
     compiler->GenerateAssertAssignable(deopt_id(),
                                        token_pos(),
-                                       try_index(),
                                        dst_type(),
                                        dst_name(),
                                        locs());
@@ -1497,7 +1490,6 @@ void AllocateObjectComp::EmitNativeCode(FlowGraphCompiler* compiler) {
   const Code& stub = Code::Handle(StubCode::GetAllocationStubForClass(cls));
   const ExternalLabel label(cls.ToCString(), stub.EntryPoint());
   compiler->GenerateCall(token_pos(),
-                         try_index(),
                          &label,
                          PcDescriptors::kOther,
                          locs());
@@ -1515,7 +1507,8 @@ void CreateClosureComp::EmitNativeCode(FlowGraphCompiler* compiler) {
   const Code& stub = Code::Handle(
       StubCode::GetAllocationStubForClosure(closure_function));
   const ExternalLabel label(closure_function.ToCString(), stub.EntryPoint());
-  compiler->GenerateCall(token_pos(), try_index(), &label,
+  compiler->GenerateCall(token_pos(),
+                         &label,
                          PcDescriptors::kOther,
                          locs());
   __ Drop(2);  // Discard type arguments and receiver.