VM: New calling convention for generated code.

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 {
 
+
+static bool MatchesPattern(uword addr, int16_t* pattern, intptr_t size) {
+  uint8_t* bytes = reinterpret_cast<uint8_t*>(addr);
+  for (intptr_t i = 0; i < size; i++) {
+    int16_t val = pattern[i];
+    if ((val >= 0) && (val != bytes[i])) {
+      return false;
+    }
+  }
+  return true;
+}
+
+
 // 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]

[srdjan, 2015/06/18 21:29:47]

You may need to update this comment.

[Florian Schneider, 2015/06/29 14:50:24]

Done.

 //  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())) {
-    ASSERT(IsValid(return_address));
     ASSERT((kCallPatternSize - 7) == Assembler::kCallExternalLabelSize);
+    ASSERT(IsValid());
   }
 
-  static const int kCallPatternSize = 14;
+  static const int kCallPatternSize = 26;
 
-  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);
+  bool IsValid() const {
+    static int16_t pattern[kCallPatternSize] = {
+      0x49, 0x8b, 0x9f, -1, -1, -1, -1,  // movq RBX, [PP + offs]
+      0x4d, 0x8b, 0xa7, -1, -1, -1, -1,  // movq CR, [PP + offs]
+      0x4d, 0x8b, 0x5c, 0x24, 0x07,      // movq TMP, [CR + insns_offs]
+      0x49, 0x83, 0xc3, 0x1f,            // addq TMP, entry_offs
+      0x41, 0xff, 0xd3                   // callq TMP
+    };
+    return MatchesPattern(start_, pattern, kCallPatternSize);
   }
 
   RawObject* ic_data() const {
     intptr_t index = InstructionPattern::IndexFromPPLoad(start_ + 3);
     return object_pool_.ObjectAt(index);
   }
 
-  uword target() const {
+  RawCode* target() const {
     intptr_t index = InstructionPattern::IndexFromPPLoad(start_ + 10);
-    return object_pool_.RawValueAt(index);
+    Code& code = Code::Handle();
+    code ^= object_pool_.ObjectAt(index);
+    return code.raw();
   }
 
-  void set_target(uword target) const {
+  void set_target(const Code& target) const {
     intptr_t index = InstructionPattern::IndexFromPPLoad(start_ + 10);
-    object_pool_.SetRawValueAt(index, target);
+    object_pool_.SetObjectAt(index, target);
     // No need to flush the instruction cache, since the code is not modified.
   }
 
  private:
   uword start_;
   const ObjectPool& object_pool_;
   DISALLOW_IMPLICIT_CONSTRUCTORS(UnoptimizedCall);
 };
 
 
@@ skipping 24 matching lines @@
 #endif  // DEBUG
   }
 
  private:
   DISALLOW_IMPLICIT_CONSTRUCTORS(UnoptimizedStaticCall);
 };
 
 
 // The expected pattern of a call where the target is loaded from
 // the object pool:
-//   0: 41 ff 97 imm32  call [PP + off]
-//   7: <- return address
+//   0: 4d 8b a7 imm32  movq CR, [PP + offs]
+//   7: 4d 8b 5c 24 07  movq TMP, [CR + insns_offs]
+//  12: 49 83 c3 1f     addq TMP, entry_offs
+//  16: 41 ff d3        callq TMP
+//  19: <- return address
 class PoolPointerCall : public ValueObject {
  public:
   explicit PoolPointerCall(uword return_address, const Code& code)
       : start_(return_address - kCallPatternSize),
         object_pool_(ObjectPool::Handle(code.GetObjectPool())) {
-    ASSERT(IsValid(return_address));
+    ASSERT(IsValid());
   }
 
-  static const int kCallPatternSize = 7;
+  static const int kCallPatternSize = 19;
 
-  static bool IsValid(uword return_address) {
-    uint8_t* code_bytes =
-        reinterpret_cast<uint8_t*>(return_address - kCallPatternSize);
-    return (code_bytes[0] == 0x41) && (code_bytes[1] == 0xFF) &&
-           (code_bytes[2] == 0x97);
+  bool IsValid() const {
+    static int16_t pattern[kCallPatternSize] = {
+      0x4d, 0x8b, 0xa7,   -1,   -1, -1, -1,  // movq CR, [PP + offs]
+      0x4d, 0x8b, 0x5c, 0x24, 0x07,          // movq TMP, [CR + insns_offs]
+      0x49, 0x83, 0xc3, 0x1f,                // addq TMP, entry_offs
+      0x41, 0xff, 0xd3                       // callq TMP
+    };
+    return MatchesPattern(start_, pattern, kCallPatternSize);
   }
 
   intptr_t pp_index() const {
     return InstructionPattern::IndexFromPPLoad(start_ + 3);
   }
 
-  uword Target() const {
-    return object_pool_.RawValueAt(pp_index());
+  RawCode* Target() const {
+    Code& code = Code::Handle();
+    code ^= object_pool_.ObjectAt(pp_index());
+    return code.raw();
   }
 
-  void SetTarget(uword target) const {
-    object_pool_.SetRawValueAt(pp_index(), target);
+  void SetTarget(const Code& target) const {
+    object_pool_.SetObjectAt(pp_index(), target);
     // No need to flush the instruction cache, since the code is not modified.
   }
 
  protected:
   uword start_;
   const ObjectPool& object_pool_;
 
  private:
   DISALLOW_IMPLICIT_CONSTRUCTORS(PoolPointerCall);
 };
 
 
-uword CodePatcher::GetStaticCallTargetAt(uword return_address,
-                                         const Code& code) {
+RawCode* CodePatcher::GetStaticCallTargetAt(uword return_address,
+                                            const Code& code) {
   ASSERT(code.ContainsInstructionAt(return_address));
   PoolPointerCall call(return_address, code);
   return call.Target();
 }
 
 
 void CodePatcher::PatchStaticCallAt(uword return_address,
                                     const Code& code,
-                                    uword new_target) {
+                                    const Code& new_target) {
   PatchPoolPointerCallAt(return_address, code, new_target);
 }
 
 
 void CodePatcher::PatchPoolPointerCallAt(uword return_address,
                                          const Code& code,
-                                         uword new_target) {
+                                         const Code& new_target) {
   ASSERT(code.ContainsInstructionAt(return_address));
   PoolPointerCall call(return_address, code);
   call.SetTarget(new_target);
 }
 
 
 void CodePatcher::PatchInstanceCallAt(uword return_address,
                                       const Code& code,
-                                      uword new_target) {
+                                      const Code& new_target) {
   ASSERT(code.ContainsInstructionAt(return_address));
   InstanceCall call(return_address, code);
   call.set_target(new_target);
 }
 
 
-uword CodePatcher::GetInstanceCallAt(uword return_address,
-                                     const Code& code,
-                                     ICData* ic_data) {
+RawCode* CodePatcher::GetInstanceCallAt(uword return_address,
+                                        const Code& code,
+                                        ICData* ic_data) {
   ASSERT(code.ContainsInstructionAt(return_address));
   InstanceCall call(return_address, code);
   if (ic_data != NULL) {
     *ic_data ^= call.ic_data();
   }
   return call.target();
 }
 
 
 intptr_t CodePatcher::InstanceCallSizeInBytes() {
@@ skipping 51 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