Implemented missing pieces of the debugger for ARM

src/arm/debug-arm.cc

 // Copyright 2006-2008 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 16 matching lines @@
 
 #include "v8.h"
 
 #include "codegen-inl.h"
 #include "debug.h"
 
 namespace v8 {
 namespace internal {
 
 #ifdef ENABLE_DEBUGGER_SUPPORT
-// Currently debug break is not supported in frame exit code on ARM.
 bool BreakLocationIterator::IsDebugBreakAtReturn() {
-  return false;
+  return Debug::IsDebugBreakAtReturn(rinfo());
 }
 
 
-// Currently debug break is not supported in frame exit code on ARM.
 void BreakLocationIterator::SetDebugBreakAtReturn() {
-  UNIMPLEMENTED();
+  // Patch the code changing the return from JS function sequence from
+  //   mov sp, fp
+  //   ldmia sp!, {fp, lr}
+  //   add sp, sp, #4
+  //   bx lr
+  // to a call to the debug break return code.
+  //   mov lr, pc
+  //   ldr pc, [pc, #-4]
+  //   <debug break return code entry point address>
+  //   bktp 0
+  CodePatcher patcher(rinfo()->pc(), 4);
+  patcher.masm()->mov(v8::internal::lr, v8::internal::pc);
+  patcher.masm()->ldr(v8::internal::pc, MemOperand(v8::internal::pc, -4));
+  patcher.Emit(Debug::debug_break_return()->entry());
+  patcher.masm()->bkpt(0);
 }
 
 
-// Currently debug break is not supported in frame exit code on ARM.
+// Restore the JS frame exit code.
 void BreakLocationIterator::ClearDebugBreakAtReturn() {
-  UNIMPLEMENTED();
+  rinfo()->PatchCode(original_rinfo()->pc(),
+                     CodeGenerator::kJSReturnSequenceLength);
 }
 
 
+// A debug break in the exit code is identified by a call.
 bool Debug::IsDebugBreakAtReturn(RelocInfo* rinfo) {
   ASSERT(RelocInfo::IsJSReturn(rinfo->rmode()));
-  // Currently debug break is not supported in frame exit code on ARM.
-  return false;
+  return rinfo->IsCallInstruction();
 }
 
 
 #define __ ACCESS_MASM(masm)
 
 
 static void Generate_DebugBreakCallHelper(MacroAssembler* masm,
                                           RegList pointer_regs) {
   // Save the content of all general purpose registers in memory. This copy in
   // memory is later pushed onto the JS expression stack for the fake JS frame
@@ skipping 19 matching lines @@
   CEntryDebugBreakStub ceb;
   __ CallStub(&ceb);
 
   // Restore the register values containing object pointers from the expression
   // stack in the reverse order as they where pushed.
   // Use sp as base to pop.
   __ CopyRegistersFromStackToMemory(sp, r3, pointer_regs);
 
   __ LeaveInternalFrame();
 
-  // Inlined ExitJSFrame ends here.
-
   // Finally restore all registers.
   __ RestoreRegistersFromMemory(kJSCallerSaved);
 
   // Now that the break point has been handled, resume normal execution by
   // jumping to the target address intended by the caller and that was
   // overwritten by the address of DebugBreakXXX.
   __ mov(ip, Operand(ExternalReference(Debug_Address::AfterBreakTarget())));
   __ ldr(ip, MemOperand(ip));
   __ Jump(ip);
 }
@@ skipping 21 matching lines @@
   //  -- lr    : return address
   //  -- [sp]  : receiver
   // -----------------------------------
   // Registers r0 and r2 contain objects that needs to be pushed on the
   // expression stack of the fake JS frame.
   Generate_DebugBreakCallHelper(masm, r0.bit() | r2.bit());
 }
 
 
 void Debug::GenerateKeyedLoadICDebugBreak(MacroAssembler* masm) {
-  // Keyed load IC not implemented on ARM.
+  // ---------- S t a t e --------------
+  //  -- lr     : return address
+  //  -- sp[0]  : key
+  //  -- sp[4]  : receiver
+  Generate_DebugBreakCallHelper(masm, 0);
 }
 
 
 void Debug::GenerateKeyedStoreICDebugBreak(MacroAssembler* masm) {
-  // Keyed store IC not implemented on ARM.
+  // ---------- S t a t e --------------
+  //  -- lr     : return address
+  //  -- sp[0]  : key
+  //  -- sp[4]  : receiver
+  Generate_DebugBreakCallHelper(masm, 0);
 }
 
 
 void Debug::GenerateCallICDebugBreak(MacroAssembler* masm) {
   // Calling convention for IC call (from ic-arm.cc)
   // ----------- S t a t e -------------
   //  -- r0: number of arguments
   //  -- r1: receiver
   //  -- lr: return address
   // -----------------------------------
@@ skipping 16 matching lines @@
 
 void Debug::GenerateReturnDebugBreak(MacroAssembler* masm) {
   // In places other than IC call sites it is expected that r0 is TOS which
   // is an object - this is not generally the case so this should be used with
   // care.
   Generate_DebugBreakCallHelper(masm, r0.bit());
 }
 
 
 void Debug::GenerateStubNoRegistersDebugBreak(MacroAssembler* masm) {
-  // Generate nothing as CodeStub CallFunction is not used on ARM.
+  // ----------- S t a t e -------------
+  //  No registers used on entry.
+  // -----------------------------------
+  Generate_DebugBreakCallHelper(masm, 0);
 }
 
 
 #undef __
 
 #endif  // ENABLE_DEBUGGER_SUPPORT
 
 } }  // namespace v8::internal