Implement missing features to run Hello world! on simulated ARM.

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/cha.h"
 #include "vm/dart_entry.h"
@@ skipping 711 matching lines @@
 
 
 void FlowGraphCompiler::AllocateRegistersLocally(Instruction* instr) {
   ASSERT(!is_optimizing());
 
   LocationSummary* locs = instr->locs();
 
   bool blocked_registers[kNumberOfCpuRegisters];
 
   // Mark all available registers free.
-  for (intptr_t i = 0; i < kFirstFreeCpuRegister; i++) {
-    blocked_registers[i] = true;
-  }
-  for (intptr_t i = kFirstFreeCpuRegister; i <= kLastFreeCpuRegister; i++) {
+  for (intptr_t i = 0; i < kNumberOfCpuRegisters; i++) {
     blocked_registers[i] = false;
   }
-  for (intptr_t i = kLastFreeCpuRegister + 1; i < kNumberOfCpuRegisters; i++) {
-    blocked_registers[i] = true;
-  }
 
   // Mark all fixed input, temp and output registers as used.
   for (intptr_t i = 0; i < locs->input_count(); i++) {
     Location loc = locs->in(i);
     if (loc.IsRegister()) {
+      // Check that a register is not specified twice in the summary.
       ASSERT(!blocked_registers[loc.reg()]);
       blocked_registers[loc.reg()] = true;
     }
   }
 
   for (intptr_t i = 0; i < locs->temp_count(); i++) {
     Location loc = locs->temp(i);
     if (loc.IsRegister()) {
+      // Check that a register is not specified twice in the summary.
       ASSERT(!blocked_registers[loc.reg()]);
       blocked_registers[loc.reg()] = true;
     }
   }
 
   if (locs->out().IsRegister()) {
     // Fixed output registers are allowed to overlap with
     // temps and inputs.
     blocked_registers[locs->out().reg()] = true;
   }
 
   // Do not allocate known registers.
   blocked_registers[CTX] = true;
   blocked_registers[SPREG] = true;
   blocked_registers[FPREG] = true;
   if (TMP != kNoRegister) {
     blocked_registers[TMP] = true;
   }
   if (PP != kNoRegister) {
     blocked_registers[PP] = true;
   }
 
+  // Block all non-free registers.
+  for (intptr_t i = 0; i < kFirstFreeCpuRegister; i++) {
+    blocked_registers[i] = true;
+  }
+  for (intptr_t i = kLastFreeCpuRegister + 1; i < kNumberOfCpuRegisters; i++) {
+    blocked_registers[i] = true;
+  }
+
   // Allocate all unallocated input locations.
   const bool should_pop = !instr->IsPushArgument();
   for (intptr_t i = locs->input_count() - 1; i >= 0; i--) {
     Location loc = locs->in(i);
     Register reg = kNoRegister;
     if (loc.IsRegister()) {
       reg = loc.reg();
     } else if (loc.IsUnallocated() || loc.IsConstant()) {
       ASSERT(loc.IsConstant() ||
              ((loc.policy() == Location::kRequiresRegister) ||
@@ skipping 338 matching lines @@
     if (i != largest_ix) {
       // Swap.
       CidTarget temp = (*sorted)[i];
       (*sorted)[i] = (*sorted)[largest_ix];
       (*sorted)[largest_ix] = temp;
     }
   }
 }
 
 }  // namespace dart