Specialize breakpoint stubs by set of live registers of the stubs they are intercepting.

runtime/vm/stub_code_x64.cc

 // Copyright (c) 2013, 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_X64)
 
 #include "vm/assembler.h"
 #include "vm/compiler.h"
 #include "vm/dart_entry.h"
@@ skipping 65 matching lines @@
   // Reserve space for arguments and align frame before entering C++ world.
   __ subq(RSP, Immediate(sizeof(NativeArguments)));
   if (OS::ActivationFrameAlignment() > 1) {
     __ andq(RSP, Immediate(~(OS::ActivationFrameAlignment() - 1)));
   }
 
   // Pass NativeArguments structure by value and call runtime.
   __ movq(Address(RSP, isolate_offset), CTX);  // Set isolate in NativeArgs.
   // There are no runtime calls to closures, so we do not need to set the tag
   // bits kClosureFunctionBit and kInstanceFunctionBit in argc_tag_.
-  __ SmiUntag(R10);
   __ movq(Address(RSP, argc_tag_offset), R10);  // Set argc in NativeArguments.
   __ leaq(RAX, Address(RBP, R10, TIMES_8, 1 * kWordSize));  // Compute argv.
   __ movq(Address(RSP, argv_offset), RAX);  // Set argv in NativeArguments.
   __ addq(RAX, Immediate(1 * kWordSize));  // Retval is next to 1st argument.
   __ movq(Address(RSP, retval_offset), RAX);  // Set retval in NativeArguments.
 #if defined(_WIN64)
   ASSERT(sizeof(NativeArguments) > CallingConventions::kRegisterTransferLimit);
   __ movq(CallingConventions::kArg1Reg, RSP);
 #endif
   __ CallCFunction(RBX);
@@ skipping 1440 matching lines @@
   __ popq(RBX);  // Restore IC data array.
   __ popq(R10);  // Restore arguments descriptor array.
   __ LeaveStubFrame();
 
   __ movq(RAX, FieldAddress(RAX, Function::instructions_offset()));
   __ addq(RAX, Immediate(Instructions::HeaderSize() - kHeapObjectTag));
   __ jmp(RAX);
 }
 
 
-//  RBX, R10: May contain arguments to runtime stub.
-//  TOS(0): return address (Dart code).
-void StubCode::GenerateBreakpointRuntimeStub(Assembler* assembler) {
+// RBX: Contains an ICData.
+// TOS(0): return address (Dart code).
+void StubCode::GenerateICCallBreakpointStub(Assembler* assembler) {
+  __ EnterStubFrame();
+  // Preserve IC data.
+  __ pushq(RBX);
+  // Room for result. Debugger stub returns address of the
+  // unpatched runtime stub.
+  __ LoadObject(R12, Object::null_object(), PP);
+  __ pushq(R12);  // Room for result.
+  __ CallRuntime(kBreakpointRuntimeHandlerRuntimeEntry, 0);
+  __ popq(RAX);  // Address of original.
+  __ popq(RBX);  // Restore IC data.
+  __ LeaveStubFrame();
+  __ jmp(RAX);   // Jump to original stub.
+}
+
+
+// RBX: Contains Smi 0 (need to preserve a GC-safe value for the lazy compile
+// stub).
+// R10: Contains an arguments descriptor.
+// TOS(0): return address (Dart code).
+void StubCode::GenerateClosureCallBreakpointStub(Assembler* assembler) {
   __ EnterStubFrame();
   // Preserve runtime args.
   __ pushq(RBX);
   __ pushq(R10);
   // Room for result. Debugger stub returns address of the
   // unpatched runtime stub.
+  __ LoadObject(R12, Object::null_object(), PP);
+  __ pushq(R12);  // Room for result.
+  __ CallRuntime(kBreakpointRuntimeHandlerRuntimeEntry, 0);
+  __ popq(RAX);  // Address of original.
+  __ popq(R10);  // Restore arguments.
+  __ popq(RBX);
+  __ LeaveStubFrame();
+  __ jmp(RAX);   // Jump to original stub.
+}
+
+
+// RBX: Garbage or function address.
+// R10: Garbage or raw argument count.
+//  TOS(0): return address (Dart code).
+void StubCode::GenerateRuntimeCallBreakpointStub(Assembler* assembler) {
+  __ EnterStubFrame();
+  // Preserve runtime args.
+  __ andq(RBX, Immediate(~kSmiTagMask));  // Make garbage GC-safe, no-op for
+                                          // aligned function pointer
+  __ pushq(RBX);
+  __ SmiTag(R10);
+  __ pushq(R10);
+  // Room for result. Debugger stub returns address of the
+  // unpatched runtime stub.
   __ LoadObject(R12, Object::null_object(), PP);
   __ pushq(R12);  // Room for result.
   __ CallRuntime(kBreakpointRuntimeHandlerRuntimeEntry, 0);
   __ popq(RAX);  // Address of original.
   __ popq(R10);  // Restore arguments.
+  __ SmiUntag(R10);
   __ popq(RBX);
   __ LeaveStubFrame();
   __ jmp(RAX);   // Jump to original stub.
 }
 
 
 // Called only from unoptimized code.
 void StubCode::GenerateDebugStepCheckStub(Assembler* assembler) {
   if (FLAG_enable_debugger) {
     // Check single stepping.
@@ skipping 287 matching lines @@
 
   __ movq(left, Address(RSP, 2 * kWordSize));
   __ movq(right, Address(RSP, 1 * kWordSize));
   GenerateIdenticalWithNumberCheckStub(assembler, left, right);
   __ ret();
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_X64