Merge experimental/a64 to bleeding_edge.

src/a64/debug-a64.cc

+// Copyright 2013 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"
+
+#if V8_TARGET_ARCH_A64
+
+#include "codegen.h"
+#include "debug.h"
+
+namespace v8 {
+namespace internal {
+
+
+#define __ ACCESS_MASM(masm)
+
+
+#ifdef ENABLE_DEBUGGER_SUPPORT
+bool BreakLocationIterator::IsDebugBreakAtReturn() {
+  return Debug::IsDebugBreakAtReturn(rinfo());
+}
+
+
+void BreakLocationIterator::SetDebugBreakAtReturn() {
+  // Patch the code emitted by FullCodeGenerator::EmitReturnSequence, changing
+  // the return from JS function sequence from
+  //   mov sp, fp
+  //   ldp fp, lr, [sp] #16
+  //   lrd ip0, [pc, #(3 * kInstructionSize)]
+  //   add sp, sp, ip0
+  //   ret
+  //   <number of paramters ...
+  //    ... plus one (64 bits)>
+  // to a call to the debug break return code.
+  //   ldr ip0, [pc, #(3 * kInstructionSize)]
+  //   blr ip0
+  //   hlt kHltBadCode    @ code should not return, catch if it does.
+  //   <debug break return code ...
+  //    ... entry point address (64 bits)>
+
+  // The patching code must not overflow the space occupied by the return
+  // sequence.
+  STATIC_ASSERT(Assembler::kJSRetSequenceInstructions >= 5);
+  PatchingAssembler patcher(reinterpret_cast<Instruction*>(rinfo()->pc()), 5);
+  byte* entry =
+      debug_info_->GetIsolate()->debug()->debug_break_return()->entry();
+
+  // The first instruction of a patched return sequence must be a load literal
+  // loading the address of the debug break return code.
+  patcher.LoadLiteral(ip0, 3 * kInstructionSize);
+  // TODO(all): check the following is correct.
+  // The debug break return code will push a frame and call statically compiled
+  // code. By using blr, even though control will not return after the branch,
+  // this call site will be registered in the frame (lr being saved as the pc
+  // of the next instruction to execute for this frame). The debugger can now
+  // iterate on the frames to find call to debug break return code.
+  patcher.blr(ip0);
+  patcher.hlt(kHltBadCode);
+  patcher.dc64(reinterpret_cast<int64_t>(entry));
+}
+
+
+void BreakLocationIterator::ClearDebugBreakAtReturn() {
+  // Reset the code emitted by EmitReturnSequence to its original state.
+  rinfo()->PatchCode(original_rinfo()->pc(),
+                     Assembler::kJSRetSequenceInstructions);
+}
+
+
+bool Debug::IsDebugBreakAtReturn(RelocInfo* rinfo) {
+  ASSERT(RelocInfo::IsJSReturn(rinfo->rmode()));
+  return rinfo->IsPatchedReturnSequence();
+}
+
+
+bool BreakLocationIterator::IsDebugBreakAtSlot() {
+  ASSERT(IsDebugBreakSlot());
+  // Check whether the debug break slot instructions have been patched.
+  return rinfo()->IsPatchedDebugBreakSlotSequence();
+}
+
+
+void BreakLocationIterator::SetDebugBreakAtSlot() {
+  // Patch the code emitted by Debug::GenerateSlots, changing the debug break
+  // slot code from
+  //   mov x0, x0    @ nop DEBUG_BREAK_NOP
+  //   mov x0, x0    @ nop DEBUG_BREAK_NOP
+  //   mov x0, x0    @ nop DEBUG_BREAK_NOP
+  //   mov x0, x0    @ nop DEBUG_BREAK_NOP
+  // to a call to the debug slot code.
+  //   ldr ip0, [pc, #(2 * kInstructionSize)]
+  //   blr ip0
+  //   <debug break slot code ...
+  //    ... entry point address (64 bits)>
+
+  // TODO(all): consider adding a hlt instruction after the blr as we don't
+  // expect control to return here. This implies increasing
+  // kDebugBreakSlotInstructions to 5 instructions.
+
+  // The patching code must not overflow the space occupied by the return
+  // sequence.
+  STATIC_ASSERT(Assembler::kDebugBreakSlotInstructions >= 4);
+  PatchingAssembler patcher(reinterpret_cast<Instruction*>(rinfo()->pc()), 4);
+  byte* entry =
+      debug_info_->GetIsolate()->debug()->debug_break_slot()->entry();
+
+  // The first instruction of a patched debug break slot must be a load literal
+  // loading the address of the debug break slot code.
+  patcher.LoadLiteral(ip0, 2 * kInstructionSize);
+  // TODO(all): check the following is correct.
+  // The debug break slot code will push a frame and call statically compiled
+  // code. By using blr, event hough control will not return after the branch,
+  // this call site will be registered in the frame (lr being saved as the pc
+  // of the next instruction to execute for this frame). The debugger can now
+  // iterate on the frames to find call to debug break slot code.
+  patcher.blr(ip0);
+  patcher.dc64(reinterpret_cast<int64_t>(entry));
+}
+
+
+void BreakLocationIterator::ClearDebugBreakAtSlot() {
+  ASSERT(IsDebugBreakSlot());
+  rinfo()->PatchCode(original_rinfo()->pc(),
+                     Assembler::kDebugBreakSlotInstructions);
+}
+
+const bool Debug::FramePaddingLayout::kIsSupported = false;
+
+static void Generate_DebugBreakCallHelper(MacroAssembler* masm,
+                                          RegList object_regs,
+                                          RegList non_object_regs,
+                                          Register scratch) {
+  {
+    FrameScope scope(masm, StackFrame::INTERNAL);
+
+    // Any live values (object_regs and non_object_regs) in caller-saved
+    // registers (or lr) need to be stored on the stack so that their values are
+    // safely preserved for a call into C code.
+    //
+    // Also:
+    //  * object_regs may be modified during the C code by the garbage
+    //    collector. Every object register must be a valid tagged pointer or
+    //    SMI.
+    //
+    //  * non_object_regs will be converted to SMIs so that the garbage
+    //    collector doesn't try to interpret them as pointers.
+    //
+    // TODO(jbramley): Why can't this handle callee-saved registers?
+    ASSERT((~kCallerSaved.list() & object_regs) == 0);
+    ASSERT((~kCallerSaved.list() & non_object_regs) == 0);
+    ASSERT((object_regs & non_object_regs) == 0);
+    ASSERT((scratch.Bit() & object_regs) == 0);
+    ASSERT((scratch.Bit() & non_object_regs) == 0);
+    ASSERT((ip0.Bit() & (object_regs | non_object_regs)) == 0);
+    ASSERT((ip1.Bit() & (object_regs | non_object_regs)) == 0);
+    STATIC_ASSERT(kSmiValueSize == 32);
+
+    CPURegList non_object_list =
+        CPURegList(CPURegister::kRegister, kXRegSize, non_object_regs);
+    while (!non_object_list.IsEmpty()) {
+      // Store each non-object register as two SMIs.
+      Register reg = Register(non_object_list.PopLowestIndex());
+      __ Push(reg);
+      __ Poke(wzr, 0);
+      __ Push(reg.W(), wzr);
+      // Stack:
+      //  jssp[12]: reg[63:32]
+      //  jssp[8]: 0x00000000 (SMI tag & padding)
+      //  jssp[4]: reg[31:0]
+      //  jssp[0]: 0x00000000 (SMI tag & padding)
+      STATIC_ASSERT((kSmiTag == 0) && (kSmiShift == 32));
+    }
+
+    if (object_regs != 0) {
+      __ PushXRegList(object_regs);
+    }
+
+#ifdef DEBUG
+    __ RecordComment("// Calling from debug break to runtime - come in - over");
+#endif
+    __ Mov(x0, 0);  // No arguments.
+    __ Mov(x1, Operand(ExternalReference::debug_break(masm->isolate())));
+
+    CEntryStub stub(1);
+    __ CallStub(&stub);
+
+    // Restore the register values from the expression stack.
+    if (object_regs != 0) {
+      __ PopXRegList(object_regs);
+    }
+
+    non_object_list =
+        CPURegList(CPURegister::kRegister, kXRegSize, non_object_regs);
+    while (!non_object_list.IsEmpty()) {
+      // Load each non-object register from two SMIs.
+      // Stack:
+      //  jssp[12]: reg[63:32]
+      //  jssp[8]: 0x00000000 (SMI tag & padding)
+      //  jssp[4]: reg[31:0]
+      //  jssp[0]: 0x00000000 (SMI tag & padding)
+      Register reg = Register(non_object_list.PopHighestIndex());
+      __ Pop(scratch, reg);
+      __ Bfxil(reg, scratch, 32, 32);
+    }
+
+    // Leave the internal frame.
+  }
+
+  // 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.
+  ExternalReference after_break_target(Debug_Address::AfterBreakTarget(),
+                                       masm->isolate());
+  __ Mov(scratch, Operand(after_break_target));
+  __ Ldr(scratch, MemOperand(scratch));
+  __ Br(scratch);
+}
+
+
+void Debug::GenerateLoadICDebugBreak(MacroAssembler* masm) {
+  // Calling convention for IC load (from ic-arm.cc).
+  // ----------- S t a t e -------------
+  //  -- x2    : name
+  //  -- lr    : return address
+  //  -- x0    : receiver
+  //  -- [sp]  : receiver
+  // -----------------------------------
+  // Registers x0 and x2 contain objects that need to be pushed on the
+  // expression stack of the fake JS frame.
+  Generate_DebugBreakCallHelper(masm, x0.Bit() | x2.Bit(), 0, x10);
+}
+
+
+void Debug::GenerateStoreICDebugBreak(MacroAssembler* masm) {
+  // Calling convention for IC store (from ic-arm.cc).
+  // ----------- S t a t e -------------
+  //  -- x0    : value
+  //  -- x1    : receiver
+  //  -- x2    : name
+  //  -- lr    : return address
+  // -----------------------------------
+  // Registers x0, x1, and x2 contain objects that need to be pushed on the
+  // expression stack of the fake JS frame.
+  Generate_DebugBreakCallHelper(masm, x0.Bit() | x1.Bit() | x2.Bit(), 0, x10);
+}
+
+
+void Debug::GenerateKeyedLoadICDebugBreak(MacroAssembler* masm) {
+  // ---------- S t a t e --------------
+  //  -- lr     : return address
+  //  -- x0     : key
+  //  -- x1     : receiver
+  Generate_DebugBreakCallHelper(masm, x0.Bit() | x1.Bit(), 0, x10);
+}
+
+
+void Debug::GenerateKeyedStoreICDebugBreak(MacroAssembler* masm) {
+  // ---------- S t a t e --------------
+  //  -- x0     : value
+  //  -- x1     : key
+  //  -- x2     : receiver
+  //  -- lr     : return address
+  Generate_DebugBreakCallHelper(masm, x0.Bit() | x1.Bit() | x2.Bit(), 0, x10);
+}
+
+
+void Debug::GenerateCompareNilICDebugBreak(MacroAssembler* masm) {
+  // Register state for CompareNil IC
+  // ----------- S t a t e -------------
+  //  -- r0    : value
+  // -----------------------------------
+  Generate_DebugBreakCallHelper(masm, x0.Bit(), 0, x10);
+}
+
+
+void Debug::GenerateCallICDebugBreak(MacroAssembler* masm) {
+  // Calling convention for IC call (from ic-arm.cc)
+  // ----------- S t a t e -------------
+  //  -- x2     : name
+  // -----------------------------------
+  Generate_DebugBreakCallHelper(masm, x2.Bit(), 0, x10);
+}
+
+
+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, x0.Bit(), 0, x10);
+}
+
+
+void Debug::GenerateCallFunctionStubDebugBreak(MacroAssembler* masm) {
+  // Register state for CallFunctionStub (from code-stubs-a64.cc).
+  // ----------- S t a t e -------------
+  //  -- x1 : function
+  // -----------------------------------
+  Generate_DebugBreakCallHelper(masm, x1.Bit(), 0, x10);
+}
+
+
+void Debug::GenerateCallFunctionStubRecordDebugBreak(MacroAssembler* masm) {
+  // Register state for CallFunctionStub (from code-stubs-a64.cc).
+  // ----------- S t a t e -------------
+  //  -- x1 : function
+  //  -- x2 : feedback array
+  //  -- x3 : slot in feedback array
+  // -----------------------------------
+  Generate_DebugBreakCallHelper(masm, x1.Bit() | x2.Bit() | x3.Bit(), 0, x10);
+}
+
+
+void Debug::GenerateCallConstructStubDebugBreak(MacroAssembler* masm) {
+  // Calling convention for CallConstructStub (from code-stubs-a64.cc).
+  // ----------- S t a t e -------------
+  //  -- x0 : number of arguments (not smi)
+  //  -- x1 : constructor function
+  // -----------------------------------
+  Generate_DebugBreakCallHelper(masm, x1.Bit(), x0.Bit(), x10);
+}
+
+
+void Debug::GenerateCallConstructStubRecordDebugBreak(MacroAssembler* masm) {
+  // Calling convention for CallConstructStub (from code-stubs-a64.cc).
+  // ----------- S t a t e -------------
+  //  -- x0 : number of arguments (not smi)
+  //  -- x1 : constructor function
+  //  -- x2     : feedback array
+  //  -- x3     : feedback slot (smi)
+  // -----------------------------------
+  Generate_DebugBreakCallHelper(
+      masm, x1.Bit() | x2.Bit() | x3.Bit(), x0.Bit(), x10);
+}
+
+
+void Debug::GenerateSlot(MacroAssembler* masm) {
+  // Generate enough nop's to make space for a call instruction. Avoid emitting
+  // the constant pool in the debug break slot code.
+  InstructionAccurateScope scope(masm, Assembler::kDebugBreakSlotInstructions);
+
+  __ RecordDebugBreakSlot();
+  for (int i = 0; i < Assembler::kDebugBreakSlotInstructions; i++) {
+    __ nop(Assembler::DEBUG_BREAK_NOP);
+  }
+}
+
+
+void Debug::GenerateSlotDebugBreak(MacroAssembler* masm) {
+  // In the places where a debug break slot is inserted no registers can contain
+  // object pointers.
+  Generate_DebugBreakCallHelper(masm, 0, 0, x10);
+}
+
+
+void Debug::GeneratePlainReturnLiveEdit(MacroAssembler* masm) {
+  masm->Abort(kLiveEditFrameDroppingIsNotSupportedOnA64);
+}
+
+
+void Debug::GenerateFrameDropperLiveEdit(MacroAssembler* masm) {
+  masm->Abort(kLiveEditFrameDroppingIsNotSupportedOnA64);
+}
+
+const bool Debug::kFrameDropperSupported = false;
+
+#endif  // ENABLE_DEBUGGER_SUPPORT
+
+} }  // namespace v8::internal
+
+#endif  // V8_TARGET_ARCH_A64