MIPS: Move stack unwinding logic into the runtime.

src/mips/code-stubs-mips.cc

Index: src/mips/code-stubs-mips.cc
diff --git a/src/mips/code-stubs-mips.cc b/src/mips/code-stubs-mips.cc
index c4fc3835529bfc025430c41320315003917e2167..c0f654a099564814a2198764de08ffd5baae1cc5 100644
--- a/src/mips/code-stubs-mips.cc
+++ b/src/mips/code-stubs-mips.cc
@@ -1036,6 +1036,59 @@ void CEntryStub::GenerateAheadOfTime(Isolate* isolate) {
 }
 
 
+static void ThrowPendingException(MacroAssembler* masm) {
+  Isolate* isolate = masm->isolate();
+
+  ExternalReference pending_handler_context_address(
+      Isolate::kPendingHandlerContextAddress, isolate);
+  ExternalReference pending_handler_code_address(
+      Isolate::kPendingHandlerCodeAddress, isolate);
+  ExternalReference pending_handler_offset_address(
+      Isolate::kPendingHandlerOffsetAddress, isolate);
+  ExternalReference pending_handler_fp_address(
+      Isolate::kPendingHandlerFPAddress, isolate);
+  ExternalReference pending_handler_sp_address(
+      Isolate::kPendingHandlerSPAddress, isolate);
+
+  // Ask the runtime for help to determine the handler. This will set r0 to

[Michael Starzinger, 2015/03/03 15:23:21]

nit: s/r0/v0/ in the comment?

[balazs.kilvady, 2015/03/03 16:17:01]

Done.

+  // contain the current pending exception, don't clobber it.
+  ExternalReference find_handler(Runtime::kFindExceptionHandler, isolate);
+  {
+    FrameScope scope(masm, StackFrame::MANUAL);
+    __ PrepareCallCFunction(3, 0, a0);
+    __ mov(a0, zero_reg);
+    __ mov(a1, zero_reg);
+    __ li(a2, Operand(ExternalReference::isolate_address(isolate)));
+    __ CallCFunction(find_handler, 3);
+  }
+
+  // Retrieve the handler context, SP and FP.
+  __ li(cp, Operand(pending_handler_context_address));
+  __ lw(cp, MemOperand(cp));
+  __ li(sp, Operand(pending_handler_sp_address));
+  __ lw(sp, MemOperand(sp));
+  __ li(fp, Operand(pending_handler_fp_address));
+  __ lw(fp, MemOperand(fp));
+
+  // If the handler is a JS frame, restore the context to the frame.
+  // (kind == ENTRY) == (fp == 0) == (cp == 0), so we could test either fp
+  // or cp.
+  Label zero;
+  __ Branch(&zero, eq, cp, Operand(zero_reg));
+  __ sw(cp, MemOperand(fp, StandardFrameConstants::kContextOffset));
+  __ bind(&zero);
+
+  // Compute the handler entry address and jump to it.
+  __ li(a1, Operand(pending_handler_code_address));
+  __ lw(a1, MemOperand(a1));
+  __ li(a2, Operand(pending_handler_offset_address));
+  __ lw(a2, MemOperand(a2));
+  __ Addu(a1, a1, Operand(Code::kHeaderSize - kHeapObjectTag));
+  __ Addu(t9, a1, a2);
+  __ Jump(t9);
+}
+
+
 void CEntryStub::Generate(MacroAssembler* masm) {
   // Called from JavaScript; parameters are on stack as if calling JS function
   // a0: number of arguments including receiver
@@ -1121,13 +1174,12 @@ void CEntryStub::Generate(MacroAssembler* masm) {
   __ LoadRoot(t0, Heap::kExceptionRootIndex);
   __ Branch(&exception_returned, eq, t0, Operand(v0));
 
-  ExternalReference pending_exception_address(
-      Isolate::kPendingExceptionAddress, isolate());
-
   // Check that there is no pending exception, otherwise we
   // should have returned the exception sentinel.
   if (FLAG_debug_code) {
     Label okay;
+    ExternalReference pending_exception_address(
+        Isolate::kPendingExceptionAddress, isolate());
     __ li(a2, Operand(pending_exception_address));
     __ lw(a2, MemOperand(a2));
     __ LoadRoot(t0, Heap::kTheHoleValueRootIndex);
@@ -1146,26 +1198,7 @@ void CEntryStub::Generate(MacroAssembler* masm) {
 
   // Handling of exception.
   __ bind(&exception_returned);
-
-  // Retrieve the pending exception.
-  __ li(a2, Operand(pending_exception_address));
-  __ lw(v0, MemOperand(a2));
-
-  // Clear the pending exception.
-  __ li(a3, Operand(isolate()->factory()->the_hole_value()));
-  __ sw(a3, MemOperand(a2));
-
-  // Special handling of termination exceptions which are uncatchable
-  // by javascript code.
-  Label throw_termination_exception;
-  __ LoadRoot(t0, Heap::kTerminationExceptionRootIndex);
-  __ Branch(&throw_termination_exception, eq, v0, Operand(t0));
-
-  // Handle normal exception.
-  __ Throw(v0);
-
-  __ bind(&throw_termination_exception);
-  __ ThrowUncatchable(v0);
+  ThrowPendingException(masm);
 }
 
 
@@ -2338,17 +2371,9 @@ void RegExpExecStub::Generate(MacroAssembler* masm) {
   __ lw(v0, MemOperand(a2, 0));
   __ Branch(&runtime, eq, v0, Operand(a1));
 
-  __ sw(a1, MemOperand(a2, 0));  // Clear pending exception.
-
-  // Check if the exception is a termination. If so, throw as uncatchable.
-  __ LoadRoot(a0, Heap::kTerminationExceptionRootIndex);
-  Label termination_exception;
-  __ Branch(&termination_exception, eq, v0, Operand(a0));
-
-  __ Throw(v0);
-
-  __ bind(&termination_exception);
-  __ ThrowUncatchable(v0);
+  // For exception, throw the exception again.
+  __ EnterExitFrame(false);
+  ThrowPendingException(masm);
 
   __ bind(&failure);
   // For failure and exception return null.