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

runtime/vm/stub_code_arm64.cc

 // Copyright (c) 2014, 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_ARM64)
 
 #include "vm/assembler.h"
 #include "vm/code_generator.h"
 #include "vm/compiler.h"
@@ skipping 27 matching lines @@
 void StubCode::GenerateCallToRuntimeStub(Assembler* assembler) {
   const intptr_t isolate_offset = NativeArguments::isolate_offset();
   const intptr_t argc_tag_offset = NativeArguments::argc_tag_offset();
   const intptr_t argv_offset = NativeArguments::argv_offset();
   const intptr_t retval_offset = NativeArguments::retval_offset();
   const intptr_t exitframe_last_param_slot_from_fp = 1;
 
   __ SetPrologueOffset();
   __ Comment("CallToRuntimeStub");
   __ EnterFrame(0);
-  __ SmiUntag(R4);
 
   // Load current Isolate pointer from Context structure into R0.
   __ LoadFieldFromOffset(R0, CTX, Context::isolate_offset(), kNoPP);
 
   // Save exit frame information to enable stack walking as we are about
   // to transition to Dart VM C++ code.
   __ StoreToOffset(SP, R0, Isolate::top_exit_frame_info_offset(), kNoPP);
 
   // Save current Context pointer into Isolate structure.
   __ StoreToOffset(CTX, R0, Isolate::top_context_offset(), kNoPP);
@@ skipping 1568 matching lines @@
   __ Pop(R5);  // Restore IC Data.
   __ LeaveStubFrame();
 
   __ LoadFieldFromOffset(R2, R0, Function::instructions_offset(), kNoPP);
   __ AddImmediate(
       R2, R2, Instructions::HeaderSize() - kHeapObjectTag, kNoPP);
   __ br(R2);
 }
 
 
-void StubCode::GenerateBreakpointRuntimeStub(Assembler* assembler) {
+// R5: Contains an ICData.
+void StubCode::GenerateICCallBreakpointStub(Assembler* assembler) {
   __ EnterStubFrame();
-  __ Push(R5);  // Save IC Data.
-  __ Push(R4);  // Save arg. desc.
+  __ Push(R5);
   __ PushObject(Object::null_object(), PP);  // Space for result.
   __ CallRuntime(kBreakpointRuntimeHandlerRuntimeEntry, 0);
   __ Pop(R0);
+  __ Pop(R5);
+  __ LeaveStubFrame();
+  __ br(R0);
+}
+
+
+// R5: Contains Smi 0 (need to preserve a GC-safe value for the lazy compile
+// stub).
+// R4: Contains an arguments descriptor.
+void StubCode::GenerateClosureCallBreakpointStub(Assembler* assembler) {
+  __ EnterStubFrame();
+  __ Push(R5);
+  __ Push(R4);
+  __ PushObject(Object::null_object(), PP);  // Space for result.
+  __ CallRuntime(kBreakpointRuntimeHandlerRuntimeEntry, 0);
+  __ Pop(R0);
   __ Pop(R4);
   __ Pop(R5);
   __ LeaveStubFrame();
   __ br(R0);
 }
 
 
+// R5: Garbage or function address.
+// R4: Garbage or raw argument count.
+void StubCode::GenerateRuntimeCallBreakpointStub(Assembler* assembler) {
+  __ EnterStubFrame();
+  __ AndImmediate(R5, R5, ~kSmiTagMask, kNoPP);
+  __ Push(R5);
+  __ SmiTag(R4);
+  __ Push(R4);
+  __ PushObject(Object::null_object(), PP);  // Space for result.
+  __ CallRuntime(kBreakpointRuntimeHandlerRuntimeEntry, 0);
+  __ Pop(R0);
+  __ Pop(R4);
+  __ SmiUntag(R4);
+  __ Pop(R5);
+  __ LeaveStubFrame();
+  __ br(R0);
+}
+
 // Called only from unoptimized code. All relevant registers have been saved.
 void StubCode::GenerateDebugStepCheckStub(
     Assembler* assembler) {
   if (FLAG_enable_debugger) {
     // Check single stepping.
     Label not_stepping;
     __ LoadFieldFromOffset(R1, CTX, Context::isolate_offset(), kNoPP);
     __ LoadFromOffset(
         R1, R1, Isolate::single_step_offset(), kNoPP, kUnsignedByte);
     __ CompareImmediate(R1, 0, kNoPP);
@@ skipping 269 matching lines @@
   const Register right = R0;
   __ LoadFromOffset(left, SP, 1 * kWordSize, kNoPP);
   __ LoadFromOffset(right, SP, 0 * kWordSize, kNoPP);
   GenerateIdenticalWithNumberCheckStub(assembler, left, right, temp);
   __ ret();
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_ARM64