Adds Stop to MIPS. Starts on MIPS call patcher.

runtime/vm/instructions_mips.cc

Index: runtime/vm/instructions_mips.cc
===================================================================
--- runtime/vm/instructions_mips.cc	(revision 20500)
+++ runtime/vm/instructions_mips.cc	(working copy)
@@ -13,8 +13,20 @@
 
 CallPattern::CallPattern(uword pc, const Code& code)
     : end_(reinterpret_cast<uword*>(pc)),
-      pool_index_(DecodePoolIndex()),
-      object_pool_(Array::Handle(code.ObjectPool())) { }
+      target_address_pool_index_(-1),
+      args_desc_load_end_(-1),
+      args_desc_pool_index_(-1),
+      ic_data_load_end_(-1),
+      ic_data_pool_index_(-1),
+      object_pool_(Array::Handle(code.ObjectPool())) {
+  ASSERT(code.ContainsInstructionAt(pc));
+  ASSERT(Back(2) == 0x0020f809);  // Last instruction: jalr RA, TMP(=R1)
+  Register reg;
+  // First end is 0 so that we begin from the delay slot of the jalr.
+  args_desc_load_end_ =
+     DecodeLoadWordFromPool(2, &reg, &target_address_pool_index_);
+  ASSERT(reg == TMP);
+}
 
 
 uword CallPattern::Back(int n) const {
@@ -23,18 +35,76 @@
 }
 
 
-int CallPattern::DecodePoolIndex() {
+int CallPattern::DecodeLoadWordFromPool(int end, Register* reg, int* index) {
+  ASSERT(end > 0);
+  uword i = Back(++end);
+  Instr* instr = Instr::At(reinterpret_cast<uword>(&i));
+  int offset = 0;
+  if ((instr->OpcodeField() == LW) && (instr->RsField() == PP)) {
+    offset = instr->SImmField();
+    *reg = instr->RtField();
+  } else {
+    ASSERT(instr->OpcodeField() == LW);
+    offset = instr->SImmField();
+    *reg = instr->RtField();
+
+    i = Back(++end);
+    instr = Instr::At(reinterpret_cast<uword>(&i));
+    ASSERT(instr->OpcodeField() == SPECIAL);
+    ASSERT(instr->FunctionField() == ADDU);
+    ASSERT(instr->RdField() == *reg);
+    ASSERT(instr->RsField() == *reg);
+    ASSERT(instr->RtField() == PP);
+
+    i = Back(++end);
+    instr = Instr::At(reinterpret_cast<uword>(&i));
+    if (instr->OpcodeField() == LUI) {
+      ASSERT(instr->RtField() == *reg);
+      offset |= (instr->UImmField() << 16);
+    } else {
+      ASSERT(instr->OpcodeField() == ORI);
+      ASSERT(instr->RtField() == *reg);
+      offset |= instr->UImmField();
+
+      if (instr->RsField() != ZR) {
+        ASSERT(instr->RsField() == *reg);
+        i = Back(++end);
+        instr = Instr::At(reinterpret_cast<uword>(&i));
+        ASSERT(instr->OpcodeField() == LUI);
+        ASSERT(instr->RtField() == *reg);
+        offset |= (instr->UImmField() << 16);
+      }
+    }
+  }
+  offset += kHeapObjectTag;
+  ASSERT(Utils::IsAligned(offset, 4));
+  *index = (offset - Array::data_offset())/4;
+  return end;
+}
+
+
+RawICData* CallPattern::IcData() {
   UNIMPLEMENTED();
-  return 0;
+  return NULL;
 }
 
 
-uword CallPattern::TargetAddress() const {
+RawArray* CallPattern::ArgumentsDescriptor() {
   UNIMPLEMENTED();
-  return 0;
+  return NULL;
 }
 
 
+uword CallPattern::TargetAddress() const {
+  ASSERT(target_address_pool_index_ >= 0);
+  const Object& target_address =
+      Object::Handle(object_pool_.At(target_address_pool_index_));
+  ASSERT(target_address.IsSmi());
+  // The address is stored in the object array as a RawSmi.
+  return reinterpret_cast<uword>(target_address.raw());
+}
+
+
 void CallPattern::SetTargetAddress(uword target_address) const {
   UNIMPLEMENTED();
 }