Move stack unwinding logic into the runtime.

src/arm/code-stubs-arm.cc

Index: src/arm/code-stubs-arm.cc
diff --git a/src/arm/code-stubs-arm.cc b/src/arm/code-stubs-arm.cc
index ad04cb5454adff449c9d3236ce65ae0aa80330a7..5cf7238a68a298709e2d1c80acd7edcdd5dfbe62 100644
--- a/src/arm/code-stubs-arm.cc
+++ b/src/arm/code-stubs-arm.cc
@@ -937,6 +937,57 @@ 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
+  // contain the current pending exception, don't clobber it.
+  ExternalReference find_handler(Runtime::kFindExceptionHandler, isolate);
+  __ mov(r0, Operand(0));
+  __ mov(r1, Operand(0));
+  __ mov(r2, Operand(ExternalReference::isolate_address(isolate)));
+  __ mov(r5, Operand(find_handler));
+  __ Call(r5);
+
+  // Retrieve the handler context, SP and FP.
+  __ mov(ip, Operand(pending_handler_context_address));

[rmcilroy, 2015/03/02 13:08:27]

I don't think you should use ip here - it could be used by the mov(..,
MemOperand(...)) macro instructions.

[Michael Starzinger, 2015/03/02 14:21:17]

Done. Thanks, got it.

+  __ ldr(cp, MemOperand(ip));
+  __ mov(ip, Operand(pending_handler_sp_address));
+  __ ldr(sp, MemOperand(ip));
+  __ mov(ip, Operand(pending_handler_fp_address));
+  __ ldr(fp, MemOperand(ip));
+
+  // 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.
+  __ tst(cp, cp);
+  __ str(cp, MemOperand(fp, StandardFrameConstants::kContextOffset), ne);
+
+  // Compute the handler entry address and jump to it.
+  ConstantPoolUnavailableScope constant_pool_unavailable(masm);
+  __ mov(r1, Operand(pending_handler_code_address));
+  __ ldr(r1, MemOperand(r1));
+  __ mov(r2, Operand(pending_handler_offset_address));
+  __ ldr(r2, MemOperand(r2));
+  if (FLAG_enable_ool_constant_pool) {
+    __ ldr(pp, FieldMemOperand(r1, Code::kConstantPoolOffset));
+  }
+  __ add(r1, r1, Operand(Code::kHeaderSize - kHeapObjectTag));
+  __ add(pc, r1, r2);
+}
+
+
 void CEntryStub::Generate(MacroAssembler* masm) {
   // Called from JavaScript; parameters are on stack as if calling JS function.
   // r0: number of arguments including receiver
@@ -1018,13 +1069,12 @@ void CEntryStub::Generate(MacroAssembler* masm) {
   __ CompareRoot(r0, Heap::kExceptionRootIndex);
   __ b(eq, &exception_returned);
 
-  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());
     __ mov(r2, Operand(pending_exception_address));
     __ ldr(r2, MemOperand(r2));
     __ CompareRoot(r2, Heap::kTheHoleValueRootIndex);
@@ -1044,26 +1094,7 @@ void CEntryStub::Generate(MacroAssembler* masm) {
 
   // Handling of exception.
   __ bind(&exception_returned);
-
-  // Retrieve the pending exception.
-  __ mov(r2, Operand(pending_exception_address));
-  __ ldr(r0, MemOperand(r2));
-
-  // Clear the pending exception.
-  __ LoadRoot(r3, Heap::kTheHoleValueRootIndex);
-  __ str(r3, MemOperand(r2));
-
-  // Special handling of termination exceptions which are uncatchable
-  // by javascript code.
-  Label throw_termination_exception;
-  __ CompareRoot(r0, Heap::kTerminationExceptionRootIndex);
-  __ b(eq, &throw_termination_exception);
-
-  // Handle normal exception.
-  __ Throw(r0);
-
-  __ bind(&throw_termination_exception);
-  __ ThrowUncatchable(r0);
+  ThrowPendingException(masm);
 }
 
 
@@ -2200,18 +2231,9 @@ void RegExpExecStub::Generate(MacroAssembler* masm) {
   __ cmp(r0, r1);
   __ b(eq, &runtime);
 
-  __ str(r1, MemOperand(r2, 0));  // Clear pending exception.
-
-  // Check if the exception is a termination. If so, throw as uncatchable.
-  __ CompareRoot(r0, Heap::kTerminationExceptionRootIndex);
-
-  Label termination_exception;
-  __ b(eq, &termination_exception);
-
-  __ Throw(r0);
-
-  __ bind(&termination_exception);
-  __ ThrowUncatchable(r0);
+  // For exception, throw the exception again.
+  __ EnterExitFrame(false);
+  ThrowPendingException(masm);
 
   __ bind(&failure);
   // For failure and exception return null.