Implement breakpoint for closure calls

runtime/vm/code_patcher_ia32.cc

 // Copyright (c) 2012, 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_IA32.
 #if defined(TARGET_ARCH_IA32)
 
 #include "vm/assembler.h"
 #include "vm/code_patcher.h"
 #include "vm/cpu.h"
@@ skipping 123 matching lines @@
   uword call_address() const {
     return start_;
   }
 
   uword start_;
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(StaticCall);
 };
 
 
+// The expected pattern of a dart closure call:
+//   mov EDX, arguments_descriptor_array
+//   call target_address
+//   <- return address
+class ClosureCall : public ValueObject {
+ public:
+  explicit ClosureCall(uword return_address)
+      : start_(return_address - (kInstr1Size + kInstr2Size)) {
+    ASSERT(IsValid(return_address));
+    ASSERT(kInstr2Size == Assembler::kCallExternalLabelSize);
+  }
+
+  static bool IsValid(uword return_address) {
+    uint8_t* code_bytes = reinterpret_cast<uint8_t*>(
+        return_address - (kInstr1Size + kInstr2Size));
+    return (code_bytes[0] == 0xBA) && (code_bytes[kInstr1Size] == 0xE8);
+  }
+
+  RawArray* arguments_descriptor() const {
+    return *reinterpret_cast<RawArray**>(start_ + 1);
+  }
+
+ private:
+  static const int kInstr1Size = 5;  // mov EDX, arguments descriptor array
+  static const int kInstr2Size = 5;  // call stub
+
+  uword return_address() const {
+    return start_ + kInstr1Size + kInstr2Size;
+  }
+  uword call_address() const { return start_; }
+
+  uword start_;
+  DISALLOW_IMPLICIT_CONSTRUCTORS(ClosureCall);
+};
+
+
+
+RawArray* CodePatcher::GetClosureArgDescAt(uword return_address,
+                                           const Code& code) {
+  ASSERT(code.ContainsInstructionAt(return_address));
+  ClosureCall call(return_address);
+  return call.arguments_descriptor();
+}
+
+
 uword CodePatcher::GetStaticCallTargetAt(uword return_address,
                                          const Code& code) {
   ASSERT(code.ContainsInstructionAt(return_address));
   StaticCall call(return_address);
   return call.target();
 }
 
 
 void CodePatcher::PatchStaticCallAt(uword return_address,
                                     const Code& code,
@@ skipping 40 matching lines @@
 }
 
 
 intptr_t CodePatcher::InstanceCallSizeInBytes() {
   return DartCallPattern::kNumInstructions * DartCallPattern::kInstructionSize;
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_IA32