From ecc1091c0a3e9b862f63a9b67b8568918460a58c Mon Sep 17 00:00:00 2001
From: Danila Fedorin <danila.fedorin@gmail.com>
Date: Fri, 31 Jan 2020 15:29:12 -0800
Subject: [PATCH] Switch to single stack in runtime for Compiler Series

---
 09/instruction.cpp  |  2 +-
 09/llvm_context.cpp | 11 +++++++++++
 09/llvm_context.hpp |  1 +
 3 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/09/instruction.cpp b/09/instruction.cpp
index 23f4258..79c8a2f 100644
--- a/09/instruction.cpp
+++ b/09/instruction.cpp
@@ -155,7 +155,7 @@ void instruction_eval::print(int indent, std::ostream& to) const {
 }
 
 void instruction_eval::gen_llvm(llvm_context& ctx, Function* f) const {
-    ctx.create_push(f, ctx.create_eval(ctx.create_pop(f)));
+    ctx.create_unwind(f);
 }
 
 void instruction_alloc::print(int indent, std::ostream& to) const {
diff --git a/09/llvm_context.cpp b/09/llvm_context.cpp
index b2982f9..18ce6e4 100644
--- a/09/llvm_context.cpp
+++ b/09/llvm_context.cpp
@@ -145,6 +145,12 @@ void llvm_context::create_functions() {
             "eval",
             &module
     );
+    functions["unwind"] = Function::Create(
+            FunctionType::get(void_type, { stack_ptr_type }, false),
+            Function::LinkageTypes::ExternalLinkage,
+            "unwind",
+            &module
+    );
 }
 
 ConstantInt* llvm_context::create_i8(int8_t i) {
@@ -199,6 +205,11 @@ Value* llvm_context::create_eval(Value* e) {
     return builder.CreateCall(eval_f, { e });
 }
 
+void llvm_context::create_unwind(Function* f) {
+    auto unwind_f = functions.at("unwind");
+    builder.CreateCall(unwind_f, { f->args().begin() });
+}
+
 Value* llvm_context::unwrap_num(Value* v) {
     auto num_ptr_type = PointerType::getUnqual(struct_types.at("node_num"));
     auto cast = builder.CreatePointerCast(v, num_ptr_type);
diff --git a/09/llvm_context.hpp b/09/llvm_context.hpp
index ca75dca..7c9a6a6 100644
--- a/09/llvm_context.hpp
+++ b/09/llvm_context.hpp
@@ -52,6 +52,7 @@ struct llvm_context {
     void create_alloc(llvm::Function*, llvm::Value*);
 
     llvm::Value* create_eval(llvm::Value*);
+    void create_unwind(llvm::Function*);
 
     llvm::Value* unwrap_num(llvm::Value*);
     llvm::Value* create_num(llvm::Value*);