Fast-codegen: Implementing try/finally on top of nesting context.

src/x64/fast-codegen-x64.cc

Index: src/x64/fast-codegen-x64.cc
diff --git a/src/x64/fast-codegen-x64.cc b/src/x64/fast-codegen-x64.cc
index 69a2ff3af66cd18823ca3a43748dae976fece66f..7e3d2fb74b39638d7858ef12feb0a0a311f598eb 100644
--- a/src/x64/fast-codegen-x64.cc
+++ b/src/x64/fast-codegen-x64.cc
@@ -1638,6 +1638,41 @@ void FastCodeGenerator::VisitThisFunction(ThisFunction* expr) {
 
 Register FastCodeGenerator::result_register() { return rax; }
 
+// ----------------------------------------------------------------------------
+// Non-local control flow support.
+
+
+void FastCodeGenerator::EnterFinallyBlock() {
+  // Cook return address on top of stack (smi encoded Code* delta)
+  __ movq(rdx, Operand(rsp, 0));
+  __ Move(rcx, masm_->CodeObject());
+  __ subq(rdx, rcx);
+  __ Integer32ToSmi(rdx, rdx);
+  __ movq(Operand(rsp, 0), rdx);
+  // Store result register while executing finally block.
+  __ push(rax);
+}
+
+
+void FastCodeGenerator::ReturnFromFinallyBlock() {
+  // Restore result register from stack.
+  __ pop(rax);
+  // Uncook return address.
+  __ movq(rdx, Operand(rsp, 0));
+  __ SmiToInteger32(rdx, rdx);
+  __ Move(rcx, masm_->CodeObject());
+  __ addq(rdx, rcx);
+  __ movq(Operand(rsp, 0), rdx);
+  // And return.
+  __ ret(0);
+}
+
+
+void FastCodeGenerator::ThrowException() {
+  __ push(rax);
+  __ CallRuntime(Runtime::kThrow, 1);
+}
+
 #undef __