Forking disassembler and simulator for Thumb2 support;...

src/arm/debug-thumb2.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
+//       with the distribution.
+//     * Neither the name of Google Inc. nor the names of its
+//       contributors may be used to endorse or promote products derived
+//       from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#include "v8.h"
+
+#include "codegen-inl.h"
+#include "debug.h"
+
+namespace v8 {
+namespace internal {
+
+#ifdef ENABLE_DEBUGGER_SUPPORT
+bool BreakLocationIterator::IsDebugBreakAtReturn() {
+  return Debug::IsDebugBreakAtReturn(rinfo());
+}
+
+
+void BreakLocationIterator::SetDebugBreakAtReturn() {
+  // 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);
+}
+
+
+// Restore the JS frame exit code.
+void BreakLocationIterator::ClearDebugBreakAtReturn() {
+  rinfo()->PatchCode(original_rinfo()->pc(),
+                     Assembler::kJSReturnSequenceLength);
+}
+
+
+// A debug break in the exit code is identified by a call.
+bool Debug::IsDebugBreakAtReturn(RelocInfo* rinfo) {
+  ASSERT(RelocInfo::IsJSReturn(rinfo->rmode()));
+  return rinfo->IsPatchedReturnSequence();
+}
+
+
+#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
+  // generated and also to the C frame generated on top of that. In the JS
+  // frame ONLY the registers containing pointers will be pushed on the
+  // expression stack. This causes the GC to update these  pointers so that
+  // they will have the correct value when returning from the debugger.
+  __ SaveRegistersToMemory(kJSCallerSaved);
+
+  __ EnterInternalFrame();
+
+  // Store the registers containing object pointers on the expression stack to
+  // make sure that these are correctly updated during GC.
+  // Use sp as base to push.
+  __ CopyRegistersFromMemoryToStack(sp, pointer_regs);
+
+#ifdef DEBUG
+  __ RecordComment("// Calling from debug break to runtime - come in - over");
+#endif
+  __ mov(r0, Operand(0));  // no arguments
+  __ mov(r1, Operand(ExternalReference::debug_break()));
+
+  CEntryStub ceb(1, ExitFrame::MODE_DEBUG);
+  __ 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();
+
+  // 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);
+}
+
+
+void Debug::GenerateLoadICDebugBreak(MacroAssembler* masm) {
+  // Calling convention for IC load (from ic-arm.cc).
+  // ----------- S t a t e -------------
+  //  -- r0    : receiver
+  //  -- r2    : name
+  //  -- 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::GenerateStoreICDebugBreak(MacroAssembler* masm) {
+  // Calling convention for IC store (from ic-arm.cc).
+  // ----------- S t a t e -------------
+  //  -- r0    : receiver
+  //  -- r2    : name
+  //  -- 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) {
+  // ---------- S t a t e --------------
+  //  -- lr     : return address
+  //  -- sp[0]  : key
+  //  -- sp[4]  : receiver
+  Generate_DebugBreakCallHelper(masm, 0);
+}
+
+
+void Debug::GenerateKeyedStoreICDebugBreak(MacroAssembler* masm) {
+  // ---------- 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
+  // -----------------------------------
+  // Register r1 contains an object that needs to be pushed on the expression
+  // stack of the fake JS frame. r0 is the actual number of arguments not
+  // encoded as a smi, therefore it cannot be on the expression stack of the
+  // fake JS frame as it can easily be an invalid pointer (e.g. 1). r0 will be
+  // pushed on the stack of the C frame and restored from there.
+  Generate_DebugBreakCallHelper(masm, r1.bit());
+}
+
+
+void Debug::GenerateConstructCallDebugBreak(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::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) {
+  // ----------- S t a t e -------------
+  //  No registers used on entry.
+  // -----------------------------------
+  Generate_DebugBreakCallHelper(masm, 0);
+}
+
+
+#undef __
+
+#endif  // ENABLE_DEBUGGER_SUPPORT
+
+} }  // namespace v8::internal