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

runtime/vm/stub_code_ia32.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_IA32)
 
 #include "vm/assembler.h"
 #include "vm/compiler.h"
 #include "vm/dart_entry.h"
@@ skipping 19 matching lines @@
 DEFINE_FLAG(bool, verify_incoming_contexts, false, "");
 
 DECLARE_FLAG(bool, enable_debugger);
 
 // Input parameters:
 //   ESP : points to return address.
 //   ESP + 4 : address of last argument in argument array.
 //   ESP + 4*EDX : address of first argument in argument array.
 //   ESP + 4*EDX + 4 : address of return value.
 //   ECX : address of the runtime function to call.
-//   EDX : number of arguments to the call as Smi.
+//   EDX : number of arguments to the call.
 // Must preserve callee saved registers EDI and EBX.
 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();
 
   __ EnterFrame(0);
-  __ SmiUntag(EDX);
 
   // Load current Isolate pointer from Context structure into EAX.
   __ movl(EAX, FieldAddress(CTX, Context::isolate_offset()));
 
   // Save exit frame information to enable stack walking as we are about
   // to transition to Dart VM C++ code.
   __ movl(Address(EAX, Isolate::top_exit_frame_info_offset()), ESP);
 
 #if defined(DEBUG)
   if (FLAG_verify_incoming_contexts) {
@@ skipping 1513 matching lines @@
   __ popl(ECX);  // Restore IC data array.
   __ popl(EDX);  // Restore arguments descriptor array.
   __ LeaveFrame();
 
   __ movl(EAX, FieldAddress(EAX, Function::instructions_offset()));
   __ addl(EAX, Immediate(Instructions::HeaderSize() - kHeapObjectTag));
   __ jmp(EAX);
 }
 
 
-// EDX, ECX: May contain arguments to runtime stub.
-void StubCode::GenerateBreakpointRuntimeStub(Assembler* assembler) {
+// ECX: Contains an ICData.
+void StubCode::GenerateICCallBreakpointStub(Assembler* assembler) {
   __ EnterStubFrame();
-  // Save runtime args.
+  // Save IC data.
+  __ pushl(ECX);
+  // Room for result. Debugger stub returns address of the
+  // unpatched runtime stub.
+  const Immediate& raw_null =
+      Immediate(reinterpret_cast<intptr_t>(Object::null()));
+  __ pushl(raw_null);  // Room for result.
+  __ CallRuntime(kBreakpointRuntimeHandlerRuntimeEntry, 0);
+  __ popl(EAX);  // Address of original stub.
+  __ popl(ECX);  // Restore IC data.
+  __ LeaveFrame();
+  __ jmp(EAX);   // Jump to original stub.
+}
+
+
+// ECX: Contains Smi 0 (need to preserve a GC-safe value for the lazy compile
+// stub).
+// EDX: Contains an arguments descriptor.
+void StubCode::GenerateClosureCallBreakpointStub(Assembler* assembler) {
+  __ EnterStubFrame();
+  // Save arguments to original stub.
   __ pushl(ECX);
   __ pushl(EDX);
   // Room for result. Debugger stub returns address of the
   // unpatched runtime stub.
+  const Immediate& raw_null =
+      Immediate(reinterpret_cast<intptr_t>(Object::null()));
+  __ pushl(raw_null);  // Room for result.
+  __ CallRuntime(kBreakpointRuntimeHandlerRuntimeEntry, 0);
+  __ popl(EAX);  // Address of original stub.
+  __ popl(EDX);  // Restore arguments to original stub.
+  __ popl(ECX);
+  __ LeaveFrame();
+  __ jmp(EAX);   // Jump to original stub.
+}
+
+
+// ECX: Garbage or function address.
+// EDX: Garbage or raw argument count.
+void StubCode::GenerateRuntimeCallBreakpointStub(Assembler* assembler) {
+  __ EnterStubFrame();
+  // Save runtime args.
+  __ andl(ECX, Immediate(~kSmiTagMask));  // Make garbage GC-safe, no-op for
+                                          // aligned function pointer
+  __ pushl(ECX);
+  __ SmiTag(EDX);  // Make garbage or raw argument count GC-safe.
+  __ pushl(EDX);
+  // Room for result. Debugger stub returns address of the
+  // unpatched runtime stub.
   const Immediate& raw_null =
       Immediate(reinterpret_cast<intptr_t>(Object::null()));
   __ pushl(raw_null);  // Room for result.
   __ CallRuntime(kBreakpointRuntimeHandlerRuntimeEntry, 0);
   __ popl(EAX);  // Address of original stub.
   __ popl(EDX);  // Restore arguments.
+  __ SmiUntag(EDX);
   __ popl(ECX);
   __ LeaveFrame();
   __ jmp(EAX);   // Jump to original stub.
 }
 
 
 // Called only from unoptimized code.
 void StubCode::GenerateDebugStepCheckStub(Assembler* assembler) {
   if (FLAG_enable_debugger) {
     // Check single stepping.
@@ skipping 286 matching lines @@
   const Register temp = ECX;
   __ movl(left, Address(ESP, 2 * kWordSize));
   __ movl(right, Address(ESP, 1 * kWordSize));
   GenerateIdenticalWithNumberCheckStub(assembler, left, right, temp);
   __ ret();
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_IA32