Fix lazy deoptimization in the presence of exceptions

runtime/vm/intermediate_language_arm64.cc

 // Copyright (c) 2014, 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/globals.h"  // Needed here to get TARGET_ARCH_ARM64.
 #if defined(TARGET_ARCH_ARM64)
 
 #include "vm/intermediate_language.h"
 
 #include "vm/compiler.h"
 #include "vm/dart_entry.h"
 #include "vm/flow_graph.h"
 #include "vm/flow_graph_compiler.h"
 #include "vm/flow_graph_range_analysis.h"
+#include "vm/instructions.h"
 #include "vm/locations.h"
 #include "vm/object_store.h"
 #include "vm/parser.h"
 #include "vm/simulator.h"
 #include "vm/stack_frame.h"
 #include "vm/stub_code.h"
 #include "vm/symbols.h"
 
 #define __ compiler->assembler()->
 #define Z (compiler->zone())
@@ skipping 197 matching lines @@
   // R2: instructions.
   // R5: Smi 0 (no IC data; the lazy-compile stub expects a GC-safe value).
   __ LoadImmediate(R5, 0);
   //??
   __ blr(R2);
   compiler->RecordSafepoint(locs());
   // Marks either the continuation point in unoptimized code or the
   // deoptimization point in optimized code, after call.
   const intptr_t deopt_id_after = Thread::ToDeoptAfter(deopt_id());
   if (compiler->is_optimizing()) {
-    compiler->AddDeoptIndexAtCall(deopt_id_after, token_pos());
+    compiler->AddDeoptIndexAtCall(deopt_id_after);
   }
   // Add deoptimization continuation point after the call and before the
   // arguments are removed.
   // In optimized code this descriptor is needed for exception handling.
   compiler->AddCurrentDescriptor(RawPcDescriptors::kDeopt,
                                  deopt_id_after,
                                  token_pos());
   __ Drop(argument_count);
 }
 
@@ skipping 2303 matching lines @@
 
 
 LocationSummary* CatchBlockEntryInstr::MakeLocationSummary(Zone* zone,
                                                            bool opt) const {
   UNREACHABLE();
   return NULL;
 }
 
 
 void CatchBlockEntryInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
+  // Ensure space for patching return sites for lazy deopt.
+  if (!FLAG_precompiled_mode && compiler->is_optimizing()) {
+    for (intptr_t i = 0;
+      i < CallPattern::kDeoptCallLengthInInstructions;
+      ++i) {
+      __ orr(R0, ZR, Operand(R0));  // nop
+    }
+  }
   __ Bind(compiler->GetJumpLabel(this));
   compiler->AddExceptionHandler(catch_try_index(),
                                 try_index(),
                                 compiler->assembler()->CodeSize(),
                                 catch_handler_types_,
                                 needs_stacktrace());
-
-  // Restore the pool pointer.
-  __ RestoreCodePointer();
-  __ LoadPoolPointer();
-
+  // On lazy deoptimization we patch the optimized code here to enter the
+  // deoptimization stub.
+  const intptr_t deopt_id = Thread::ToDeoptAfter(GetDeoptId());
+  if (compiler->is_optimizing()) {
+    compiler->AddDeoptIndexAtCall(deopt_id);
+  } else {
+    compiler->AddCurrentDescriptor(RawPcDescriptors::kDeopt,
+                                   deopt_id,
+                                   TokenPosition::kNoSource);
+  }
   if (HasParallelMove()) {
     compiler->parallel_move_resolver()->EmitNativeCode(parallel_move());
   }
 
   // Restore SP from FP as we are coming from a throw and the code for
   // popping arguments has not been run.
   const intptr_t fp_sp_dist =
       (kFirstLocalSlotFromFp + 1 - compiler->StackSize()) * kWordSize;
   ASSERT(fp_sp_dist <= 0);
   __ AddImmediate(SP, FP, fp_sp_dist);
@@ skipping 3196 matching lines @@
                                 1,
                                 locs());
   __ Drop(1);
   __ Pop(result);
 }
 
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_ARM64