VM: Link native calls lazily.

runtime/vm/code_patcher_x64.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_X64.
 #if defined(TARGET_ARCH_X64)
 
 #include "vm/assembler.h"
 #include "vm/code_patcher.h"
 #include "vm/cpu.h"
 #include "vm/dart_entry.h"
 #include "vm/flow_graph_compiler.h"
 #include "vm/instructions.h"
 #include "vm/object.h"
 #include "vm/raw_object.h"
 
 namespace dart {
 
 // The expected pattern of a Dart unoptimized call (static and instance):
 //   0: 49 8b 9f imm32  mov RBX, [PP + off]
 //   7: 41 ff 97 imm32  call [PP + off]
 //  14 <- return address
 class UnoptimizedCall : public ValueObject {
  public:
   UnoptimizedCall(uword return_address, const Code& code)
-      : start_(return_address - kCallPatternSize),
-        object_pool_(ObjectPool::Handle(code.GetObjectPool())) {
+      : object_pool_(ObjectPool::Handle(code.GetObjectPool())),
+        start_(return_address - kCallPatternSize) {
     ASSERT(IsValid(return_address));
     ASSERT((kCallPatternSize - 7) == Assembler::kCallExternalLabelSize);
   }
 
   static const int kCallPatternSize = 14;
 
   static bool IsValid(uword return_address) {
     uint8_t* code_bytes =
         reinterpret_cast<uint8_t*>(return_address - kCallPatternSize);
     return (code_bytes[0] == 0x49) && (code_bytes[1] == 0x8B) &&
            (code_bytes[2] == 0x9F) &&
            (code_bytes[7] == 0x41) && (code_bytes[8] == 0xFF) &&
            (code_bytes[9] == 0x97);
   }
 
+  intptr_t argument_index() const {
+    return IndexFromPPLoad(start_ + 3);
+  }
+
   RawObject* ic_data() const {
-    intptr_t index = IndexFromPPLoad(start_ + 3);
-    return object_pool_.ObjectAt(index);
+    return object_pool_.ObjectAt(argument_index());
   }
 
   uword target() const {
     intptr_t index = IndexFromPPLoad(start_ + 10);
     return object_pool_.RawValueAt(index);
   }
 
   void set_target(uword target) const {
     intptr_t index = IndexFromPPLoad(start_ + 10);
     object_pool_.SetRawValueAt(index, target);
     // No need to flush the instruction cache, since the code is not modified.
   }
 
+ protected:
+  const ObjectPool& object_pool_;
+
  private:
   uword start_;
-  const ObjectPool& object_pool_;
   DISALLOW_IMPLICIT_CONSTRUCTORS(UnoptimizedCall);
 };
 
 
+class NativeCall : public UnoptimizedCall {
+ public:
+  NativeCall(uword return_address, const Code& code)
+      : UnoptimizedCall(return_address, code) {
+  }
+
+  NativeFunction native_function() const {
+    return reinterpret_cast<NativeFunction>(
+        object_pool_.RawValueAt(argument_index()));
+  }
+
+  void set_native_function(NativeFunction func) const {
+    object_pool_.SetRawValueAt(argument_index(),
+        reinterpret_cast<uword>(func));
+  }
+
+ private:
+  DISALLOW_IMPLICIT_CONSTRUCTORS(NativeCall);
+};
+
+
 class InstanceCall : public UnoptimizedCall {
  public:
   InstanceCall(uword return_address, const Code& code)
       : UnoptimizedCall(return_address, code) {
 #if defined(DEBUG)
     ICData& test_ic_data = ICData::Handle();
     test_ic_data ^= ic_data();
     ASSERT(test_ic_data.NumArgsTested() > 0);
 #endif  // DEBUG
   }
@@ skipping 128 matching lines @@
   UnoptimizedStaticCall static_call(return_address, code);
   ICData& ic_data = ICData::Handle();
   ic_data ^= static_call.ic_data();
   if (ic_data_result != NULL) {
     *ic_data_result = ic_data.raw();
   }
   return ic_data.GetTargetAt(0);
 }
 
 
+void CodePatcher::PatchNativeCallAt(uword return_address,
+                                    const Code& code,
+                                    NativeFunction target,
+                                    const Code& trampoline) {
+  ASSERT(code.ContainsInstructionAt(return_address));
+  NativeCall call(return_address, code);
+  call.set_target(trampoline.EntryPoint());
+  call.set_native_function(target);
+}
+
+
+uword CodePatcher::GetNativeCallAt(uword return_address,
+                                   const Code& code,
+                                   NativeFunction* target) {
+  ASSERT(code.ContainsInstructionAt(return_address));
+  NativeCall call(return_address, code);
+  *target = call.native_function();
+  return call.target();
+}
+
+
 // The expected code pattern of an edge counter in unoptimized code:
 //  49 8b 87 imm32    mov RAX, [PP + offset]
 class EdgeCounter : public ValueObject {
  public:
   EdgeCounter(uword pc, const Code& code)
       : end_(pc - FlowGraphCompiler::EdgeCounterIncrementSizeInBytes()),
         object_pool_(ObjectPool::Handle(code.GetObjectPool())) {
     ASSERT(IsValid(end_));
   }
 
@@ skipping 14 matching lines @@
 
 RawObject* CodePatcher::GetEdgeCounterAt(uword pc, const Code& code) {
   ASSERT(code.ContainsInstructionAt(pc));
   EdgeCounter counter(pc, code);
   return counter.edge_counter();
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_X64