Adds Stop to MIPS. Starts on MIPS call patcher.

runtime/vm/assembler_mips.cc

Index: runtime/vm/assembler_mips.cc
===================================================================
--- runtime/vm/assembler_mips.cc	(revision 20500)
+++ runtime/vm/assembler_mips.cc	(working copy)
@@ -9,7 +9,7 @@
 
 namespace dart {
 
-DEFINE_FLAG(bool, print_stop_message, true, "Print stop message.");
+DEFINE_FLAG(bool, print_stop_message, false, "Print stop message.");
 
 
 void Assembler::InitializeMemoryWithBreakpoints(uword data, int length) {
@@ -27,11 +27,11 @@
   ASSERT(!label->IsBound());
   int bound_pc = buffer_.Size();
   while (label->IsLinked()) {
-    int32_t position = label->Position();
-    int32_t next = buffer_.Load<int32_t>(position);
+    const int32_t position = label->Position();
+    const int32_t next = buffer_.Load<int32_t>(position);
     // Reletive destination from an instruction after the branch.

[regis, 2013/03/26 17:52:35]

Relative

-    int32_t dest = bound_pc - (position + Instr::kInstrSize);
-    int32_t encoded = Assembler::EncodeBranchOffset(dest, next);
+    const int32_t dest = bound_pc - (position + Instr::kInstrSize);
+    const int32_t encoded = Assembler::EncodeBranchOffset(dest, next);
     buffer_.Store<int32_t>(position, encoded);
     label->position_ = Assembler::DecodeBranchOffset(next);
   }
@@ -56,6 +56,79 @@
   return (((instr & kBranchOffsetMask) << 16) >> 14);
 }
 
+
+void Assembler::LoadWordFromPoolOffset(Register rd, int32_t offset) {
+  ASSERT(rd != PP);
+  if (Address::CanHoldOffset(offset)) {
+    lw(rd, Address(PP, offset));
+  } else {
+    const uint16_t offset_low = Utils::Low16Bits(offset);
+    const uint16_t offset_high = Utils::High16Bits(offset);
+    if (offset_high != 0) {
+      lui(rd, Immediate(offset_high));
+      if (Address::CanHoldOffset(offset_low)) {

[regis, 2013/03/26 17:52:35]

You need this test, because you chopped off 16 bits of the offset (unsigned),
and the lw instruction takes a signed offset.
Could you subtract the signed 16 lower bits of the 32-bit offset instead?
Something like this:

const int16_t offset_low = Utils::Low16Bits(offset);  // Signed.
offset -= offset_low;
const uint16_t offset_high = Utils::High16Bits(offset);  // Unsigned.
if (offset_high != 0) {
  lui(rd, Immediate(offset_high));
  addu(rd, rd, PP);
  lw(rd, Address(rd, offset_low));
} else {
  lw(rd, Address(PP, offset_low));
}

 

+        addu(rd, rd, PP);
+        lw(rd, Address(rd, offset_low));
+      } else {
+        ori(rd, rd, Immediate(offset_low));
+        addu(rd, rd, PP);
+        lw(rd, Address(rd));
+      }
+    } else {
+      ori(rd, ZR, Immediate(offset_low));
+      addu(rd, rd, PP);
+      lw(rd, Address(rd));
+    }
+  }
+}
+
+
+int32_t Assembler::AddObject(const Object& obj) {
+  ASSERT(obj.IsNotTemporaryScopedHandle());
+  ASSERT(obj.IsOld());
+  if (object_pool_.IsNull()) {
+    // The object pool cannot be used in the vm isolate.
+    ASSERT(Isolate::Current() != Dart::vm_isolate());
+    object_pool_ = GrowableObjectArray::New(Heap::kOld);
+  }
+  for (int i = 0; i < object_pool_.Length(); i++) {
+    if (object_pool_.At(i) == obj.raw()) {
+      return i;
+    }
+  }
+  object_pool_.Add(obj, Heap::kOld);
+  return object_pool_.Length() - 1;
+}
+
+
+int32_t Assembler::AddExternalLabel(const ExternalLabel* label) {
+  if (object_pool_.IsNull()) {
+    // The object pool cannot be used in the vm isolate.
+    ASSERT(Isolate::Current() != Dart::vm_isolate());
+    object_pool_ = GrowableObjectArray::New(Heap::kOld);
+  }
+  const word address = label->address();
+  ASSERT(Utils::IsAligned(address, 4));
+  // The address is stored in the object array as a RawSmi.
+  const Smi& smi = Smi::Handle(Smi::New(address >> kSmiTagShift));
+  // Do not reuse an existing entry, since each reference may be patched
+  // independently.
+  object_pool_.Add(smi, Heap::kOld);
+  return object_pool_.Length() - 1;
+}
+
+
+void Assembler::Stop(const char* message) {
+  if (FLAG_print_stop_message) {
+    UNIMPLEMENTED();
+  }
+  Label stop;
+  b(&stop);
+  Emit(reinterpret_cast<int32_t>(message));
+  Bind(&stop);
+  break_(Instr::kStopMessageCode);
+}
+
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_MIPS