VM: Make optimized try-catch work in DBC.

runtime/vm/flow_graph_compiler.cc

 // Copyright (c) 2013, 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_XXX.
 
 #include "vm/flow_graph_compiler.h"
 
 #include "vm/bit_vector.h"
 #include "vm/cha.h"
@@ skipping 829 matching lines @@
         (registers->FpuRegisterCount() * kFpuRegisterSpillFactor);
 
     BitmapBuilder* bitmap = locs->stack_bitmap();
 
     // An instruction may have two safepoints in deferred code. The
     // call to RecordSafepoint has the side-effect of appending the live
     // registers to the bitmap. This is why the second call to RecordSafepoint
     // with the same instruction (and same location summary) sees a bitmap that
     // is larger that StackSize(). It will never be larger than StackSize() +
     // live_registers_size.
-    ASSERT(bitmap->Length() <= (spill_area_size + live_registers_size));
     // The first safepoint will grow the bitmap to be the size of
     // spill_area_size but the second safepoint will truncate the bitmap and
     // append the live registers to it again. The bitmap produced by both calls
     // will be the same.
-    bitmap->SetLength(spill_area_size);

[zra, 2016/10/04 15:22:48]

Don't you still need this line in non-DBC?

[Florian Schneider, 2016/10/04 17:01:04]

Oops, yes of course. Thanks!

+#if !defined(TARGET_ARCH_DBC)
+    ASSERT(bitmap->Length() <= (spill_area_size + live_registers_size));
+#else
+    if (bitmap->Length() <= (spill_area_size + live_registers_size)) {
+      bitmap->SetLength(Utils::Maximum(bitmap->Length(), spill_area_size));
+    }
+#endif
 
     // Mark the bits in the stack map in the same order we push registers in
     // slow path code (see FlowGraphCompiler::SaveLiveRegisters).
     //
     // Slow path code can have registers at the safepoint.
     if (!locs->always_calls()) {
       RegisterSet* regs = locs->live_registers();
       if (regs->FpuRegisterCount() > 0) {
         // Denote FPU registers with 0 bits in the stackmap.  Based on the
         // assumption that there are normally few live FPU registers, this
@@ skipping 1129 matching lines @@
 
 
 void FlowGraphCompiler::FrameStateClear() {
   ASSERT(!is_optimizing());
   frame_state_.TruncateTo(0);
 }
 #endif  // defined(DEBUG) && !defined(TARGET_ARCH_DBC)
 
 
 }  // namespace dart