Initial SIMDBC interpreter.

runtime/vm/debugger_dbc.cc

-// Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
+// Copyright (c) 2016, 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"
-#if defined(TARGET_ARCH_IA32)
-
-#include "vm/debugger.h"
+#if defined(TARGET_ARCH_DBC)
 
 #include "vm/code_patcher.h"
 #include "vm/cpu.h"
-#include "vm/disassembler.h"
-#include "vm/object.h"
-#include "vm/os.h"
-#include "vm/stack_frame.h"
+#include "vm/debugger.h"
+#include "vm/instructions.h"
 #include "vm/stub_code.h"
 
 namespace dart {
 
 #ifndef PRODUCT
 
 RawCode* CodeBreakpoint::OrigStubAddress() const {
-  return saved_value_;
+  return reinterpret_cast<RawCode*>(static_cast<uintptr_t>(saved_value_));
 }
 
 
+static Instr* CallInstructionFromReturnAddress(uword pc) {
+  return reinterpret_cast<Instr*>(pc) - 1;
+}
+
+
 void CodeBreakpoint::PatchCode() {
   ASSERT(!is_enabled_);
   const Code& code = Code::Handle(code_);
   const Instructions& instrs = Instructions::Handle(code.instructions());
-  Code& stub_target = Code::Handle();
   {
     WritableInstructionsScope writable(instrs.EntryPoint(), instrs.size());
+    saved_value_ = *CallInstructionFromReturnAddress(pc_);
     switch (breakpoint_kind_) {
       case RawPcDescriptors::kIcCall:
       case RawPcDescriptors::kUnoptStaticCall: {
-        stub_target = StubCode::ICCallBreakpoint_entry()->code();
+        // DebugBreak has an A operand matching the call it replaces.
+        // This ensures that Return instructions continue to work - as they
+        // look at calls to figure out how many arguments to drop.
+        *CallInstructionFromReturnAddress(pc_) =
+            Bytecode::Encode(Bytecode::kDebugBreak,
+                             Bytecode::DecodeArgc(saved_value_),
+                             0,
+                             0);
         break;
       }
+
       case RawPcDescriptors::kRuntimeCall: {
-        saved_value_ = CodePatcher::GetStaticCallTargetAt(pc_, code);
-        stub_target = StubCode::RuntimeCallBreakpoint_entry()->code();
+        *CallInstructionFromReturnAddress(pc_) = Bytecode::kDebugBreak;
         break;
       }
+
       default:
         UNREACHABLE();
     }
-    saved_value_ = CodePatcher::GetStaticCallTargetAt(pc_, code);
-    CodePatcher::PatchStaticCallAt(pc_, code, stub_target);
   }
   is_enabled_ = true;
 }
 
 
 void CodeBreakpoint::RestoreCode() {
   ASSERT(is_enabled_);
   const Code& code = Code::Handle(code_);
   const Instructions& instrs = Instructions::Handle(code.instructions());
   {
     WritableInstructionsScope writable(instrs.EntryPoint(), instrs.size());
     switch (breakpoint_kind_) {
       case RawPcDescriptors::kIcCall:
       case RawPcDescriptors::kUnoptStaticCall:
       case RawPcDescriptors::kRuntimeCall: {
-        CodePatcher::PatchStaticCallAt(pc_, code, Code::Handle(saved_value_));
+        *CallInstructionFromReturnAddress(pc_) = saved_value_;
         break;
       }
       default:
         UNREACHABLE();
     }
   }
   is_enabled_ = false;
 }
 
 #endif  // !PRODUCT
 
 }  // namespace dart
 
-#endif  // defined TARGET_ARCH_IA32
+#endif  // defined TARGET_ARCH_DBC