VM: Make optimized try-catch work in DBC.

runtime/vm/flow_graph_compiler.cc

Index: runtime/vm/flow_graph_compiler.cc
diff --git a/runtime/vm/flow_graph_compiler.cc b/runtime/vm/flow_graph_compiler.cc
index e4f461e6408809306ad2e8c3f59e579681dffaad..4e70de1d616c696562af6e04aa4a0eb8e800f947 100644
--- a/runtime/vm/flow_graph_compiler.cc
+++ b/runtime/vm/flow_graph_compiler.cc
@@ -845,12 +845,18 @@ void FlowGraphCompiler::RecordSafepoint(LocationSummary* locs,
     // 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.
+#if !defined(TARGET_ARCH_DBC)
+    ASSERT(bitmap->Length() <= (spill_area_size + live_registers_size));
     bitmap->SetLength(spill_area_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).