Submit debug-mips.cc.

src/mips/debug-mips.cc

Index: src/mips/debug-mips.cc
diff --git a/src/mips/debug-mips.cc b/src/mips/debug-mips.cc
index 1b3e27a534d3a60890e01e5520bc120675c60e69..ee7a93be1191bf54c0890e0b5465a1bc1c18a901 100644
--- a/src/mips/debug-mips.cc
+++ b/src/mips/debug-mips.cc
@@ -1,4 +1,4 @@
-// Copyright 2010 the V8 project authors. All rights reserved.
+// Copyright 2011 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:
@@ -40,106 +40,259 @@ namespace internal {
 #ifdef ENABLE_DEBUGGER_SUPPORT
 
 bool BreakLocationIterator::IsDebugBreakAtReturn() {
-  UNIMPLEMENTED_MIPS();
-  return false;
+  return Debug::IsDebugBreakAtReturn(rinfo());
 }
 
 
 void BreakLocationIterator::SetDebugBreakAtReturn() {
-  UNIMPLEMENTED_MIPS();
+  // Mips return sequence:
+  // mov sp, fp
+  // lw fp, sp(0)
+  // lw ra, sp(4)
+  // addiu sp, sp, 8
+  // addiu sp, sp, N
+  // jr ra
+  // nop (in branch delay slot)
+
+  // Make sure this constant matches the number if instrucntions we emit.
+  ASSERT(Assembler::kJSReturnSequenceInstructions == 7);
+  CodePatcher patcher(rinfo()->pc(), Assembler::kJSReturnSequenceInstructions);
+  // li and Call pseudo-instructions emit two instructions each.
+  patcher.masm()->li(v8::internal::t9,
+      Operand(reinterpret_cast<int32_t>(
+          Isolate::Current()->debug()->debug_break_return()->entry())));
+  patcher.masm()->Call(v8::internal::t9);
+  patcher.masm()->nop();
+  patcher.masm()->nop();
+  patcher.masm()->nop();
+
+  // TODO(mips): Open issue about using breakpoint instruction instead of nops.
+  // patcher.masm()->bkpt(0);
 }
 
 
 // Restore the JS frame exit code.
 void BreakLocationIterator::ClearDebugBreakAtReturn() {
-  UNIMPLEMENTED_MIPS();
+  rinfo()->PatchCode(original_rinfo()->pc(),
+                     Assembler::kJSReturnSequenceInstructions);
 }
 
 
 // A debug break in the exit code is identified by the JS frame exit code
-// having been patched with li/call psuedo-instrunction (liu/ori/jalr)
+// having been patched with li/call psuedo-instrunction (liu/ori/jalr).
 bool Debug::IsDebugBreakAtReturn(RelocInfo* rinfo) {
-  UNIMPLEMENTED_MIPS();
-  return false;
+  ASSERT(RelocInfo::IsJSReturn(rinfo->rmode()));
+  return rinfo->IsPatchedReturnSequence();
 }
 
 
 bool BreakLocationIterator::IsDebugBreakAtSlot() {
-  UNIMPLEMENTED_MIPS();
-  return false;
+  ASSERT(IsDebugBreakSlot());
+  // Check whether the debug break slot instructions have been patched.
+  return rinfo()->IsPatchedDebugBreakSlotSequence();
 }
 
 
 void BreakLocationIterator::SetDebugBreakAtSlot() {
-  UNIMPLEMENTED_MIPS();
+  ASSERT(IsDebugBreakSlot());
+  // Patch the code changing the debug break slot code from:
+  //   nop(DEBUG_BREAK_NOP) - nop(1) is sll(zero_reg, zero_reg, 1)
+  //   nop(DEBUG_BREAK_NOP)
+  //   nop(DEBUG_BREAK_NOP)
+  //   nop(DEBUG_BREAK_NOP)
+  // to a call to the debug break slot code.
+  //   li t9, address   (lui t9 / ori t9 instruction pair)
+  //   call t9          (jalr t9 / nop instruction pair)
+  CodePatcher patcher(rinfo()->pc(), Assembler::kDebugBreakSlotInstructions);
+  patcher.masm()->li(v8::internal::t9, Operand(reinterpret_cast<int32_t>(
+      Isolate::Current()->debug()->debug_break_return()->entry())));
+  patcher.masm()->Call(v8::internal::t9);
 }
 
 
 void BreakLocationIterator::ClearDebugBreakAtSlot() {
-  UNIMPLEMENTED_MIPS();
+  ASSERT(IsDebugBreakSlot());
+  rinfo()->PatchCode(original_rinfo()->pc(),
+                     Assembler::kDebugBreakSlotInstructions);
 }
 
 
 #define __ ACCESS_MASM(masm)
 
 
+
+static void Generate_DebugBreakCallHelper(MacroAssembler* masm,
+                                          RegList object_regs,
+                                          RegList non_object_regs) {
+  __ EnterInternalFrame();
+
+  // Store the registers containing live values on the expression stack to
+  // make sure that these are correctly updated during GC. Non object values
+  // are stored as a smi causing it to be untouched by GC.
+  ASSERT((object_regs & ~kJSCallerSaved) == 0);
+  ASSERT((non_object_regs & ~kJSCallerSaved) == 0);
+  ASSERT((object_regs & non_object_regs) == 0);
+  if ((object_regs | non_object_regs) != 0) {
+    for (int i = 0; i < kNumJSCallerSaved; i++) {
+      int r = JSCallerSavedCode(i);
+      Register reg = { r };
+      if ((non_object_regs & (1 << r)) != 0) {
+        if (FLAG_debug_code) {
+          __ And(at, reg, 0xc0000000);
+          __ Assert(eq, "Unable to encode value as smi", at, Operand(zero_reg));
+        }
+        __ sll(reg, reg, kSmiTagSize);
+      }
+    }
+    __ MultiPush(object_regs | non_object_regs);
+  }
+
+#ifdef DEBUG
+  __ RecordComment("// Calling from debug break to runtime - come in - over");
+#endif
+  __ mov(a0, zero_reg);  // No arguments.
+  __ li(a1, Operand(ExternalReference::debug_break(masm->isolate())));
+
+  CEntryStub ceb(1);
+  __ CallStub(&ceb);
+
+  // Restore the register values from the expression stack.
+  if ((object_regs | non_object_regs) != 0) {
+    __ MultiPop(object_regs | non_object_regs);
+    for (int i = 0; i < kNumJSCallerSaved; i++) {
+      int r = JSCallerSavedCode(i);
+      Register reg = { r };
+      if ((non_object_regs & (1 << r)) != 0) {
+        __ srl(reg, reg, kSmiTagSize);
+      }
+      if (FLAG_debug_code &&
+          (((object_regs |non_object_regs) & (1 << r)) == 0)) {
+        __ li(reg, kDebugZapValue);
+      }
+    }
+  }
+
+  __ LeaveInternalFrame();
+
+  // 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.
+  __ li(t9, Operand(
+      ExternalReference(Debug_Address::AfterBreakTarget(), masm->isolate())));
+  __ lw(t9, MemOperand(t9));
+  __ Jump(t9);
+}
+
+
 void Debug::GenerateLoadICDebugBreak(MacroAssembler* masm) {
-  UNIMPLEMENTED_MIPS();
+  // Calling convention for IC load (from ic-mips.cc).
+  // ----------- S t a t e -------------
+  //  -- a2    : name
+  //  -- ra    : return address
+  //  -- a0    : receiver
+  //  -- [sp]  : receiver
+  // -----------------------------------
+  // Registers a0 and a2 contain objects that need to be pushed on the
+  // expression stack of the fake JS frame.
+  Generate_DebugBreakCallHelper(masm, a0.bit() | a2.bit(), 0);
 }
 
 
 void Debug::GenerateStoreICDebugBreak(MacroAssembler* masm) {
-  UNIMPLEMENTED_MIPS();
+  // Calling convention for IC store (from ic-mips.cc).
+  // ----------- S t a t e -------------
+  //  -- a0    : value
+  //  -- a1    : receiver
+  //  -- a2    : name
+  //  -- ra    : return address
+  // -----------------------------------
+  // Registers a0, a1, and a2 contain objects that need to be pushed on the
+  // expression stack of the fake JS frame.
+  Generate_DebugBreakCallHelper(masm, a0.bit() | a1.bit() | a2.bit(), 0);
 }
 
 
 void Debug::GenerateKeyedLoadICDebugBreak(MacroAssembler* masm) {
-  UNIMPLEMENTED_MIPS();
+  // ---------- S t a t e --------------
+  //  -- ra  : return address
+  //  -- a0  : key
+  //  -- a1  : receiver
+  Generate_DebugBreakCallHelper(masm, a0.bit() | a1.bit(), 0);
 }
 
 
 void Debug::GenerateKeyedStoreICDebugBreak(MacroAssembler* masm) {
-  UNIMPLEMENTED_MIPS();
+  // ---------- S t a t e --------------
+  //  -- a0     : value
+  //  -- a1     : key
+  //  -- a2     : receiver
+  //  -- ra     : return address
+  Generate_DebugBreakCallHelper(masm, a0.bit() | a1.bit() | a2.bit(), 0);
 }
 
 
 void Debug::GenerateCallICDebugBreak(MacroAssembler* masm) {
-  UNIMPLEMENTED_MIPS();
+  // Calling convention for IC call (from ic-mips.cc).
+  // ----------- S t a t e -------------
+  //  -- a2: name
+  // -----------------------------------
+  Generate_DebugBreakCallHelper(masm, a2.bit(), 0);
 }
 
 
 void Debug::GenerateConstructCallDebugBreak(MacroAssembler* masm) {
-  UNIMPLEMENTED_MIPS();
+  // Calling convention for construct call (from builtins-mips.cc).
+  //  -- a0     : number of arguments (not smi)
+  //  -- a1     : constructor function
+  Generate_DebugBreakCallHelper(masm, a1.bit(), a0.bit());
 }
 
 
 void Debug::GenerateReturnDebugBreak(MacroAssembler* masm) {
-  UNIMPLEMENTED_MIPS();
+  // In places other than IC call sites it is expected that v0 is TOS which
+  // is an object - this is not generally the case so this should be used with
+  // care.
+  Generate_DebugBreakCallHelper(masm, v0.bit(), 0);
 }
 
 
 void Debug::GenerateStubNoRegistersDebugBreak(MacroAssembler* masm) {
-  UNIMPLEMENTED_MIPS();
+  // ----------- S t a t e -------------
+  //  No registers used on entry.
+  // -----------------------------------
+  Generate_DebugBreakCallHelper(masm, 0, 0);
 }
 
 
 void Debug::GenerateSlot(MacroAssembler* masm) {
-  UNIMPLEMENTED_MIPS();
+  // Generate enough nop's to make space for a call instruction. Avoid emitting
+  // the trampoline pool in the debug break slot code.
+  Assembler::BlockTrampolinePoolScope block_trampoline_pool(masm);
+  Label check_codesize;
+  __ bind(&check_codesize);
+  __ RecordDebugBreakSlot();
+  for (int i = 0; i < Assembler::kDebugBreakSlotInstructions; i++) {
+    __ nop(MacroAssembler::DEBUG_BREAK_NOP);
+  }
+  ASSERT_EQ(Assembler::kDebugBreakSlotInstructions,
+            masm->InstructionsGeneratedSince(&check_codesize));
 }
 
 
 void Debug::GenerateSlotDebugBreak(MacroAssembler* masm) {
-  UNIMPLEMENTED_MIPS();
+  // In the places where a debug break slot is inserted no registers can contain
+  // object pointers.
+  Generate_DebugBreakCallHelper(masm, 0, 0);
 }
 
 
 void Debug::GeneratePlainReturnLiveEdit(MacroAssembler* masm) {
-  UNIMPLEMENTED_MIPS();
+  masm->Abort("LiveEdit frame dropping is not supported on mips");
 }
 
 
 void Debug::GenerateFrameDropperLiveEdit(MacroAssembler* masm) {
-  UNIMPLEMENTED_MIPS();
+  masm->Abort("LiveEdit frame dropping is not supported on mips");
 }