From 13214cee966f37ecfe2549461bdba0924d17d0ac Mon Sep 17 00:00:00 2001
From: Danila Fedorin <danila.fedorin@gmail.com>
Date: Thu, 10 Sep 2020 17:32:16 -0700
Subject: [PATCH] Try out unboxing integers.

---
 code/compiler/13/llvm_context.cpp |  7 +------
 code/compiler/13/runtime.c        | 23 +++++++++++++----------
 2 files changed, 14 insertions(+), 16 deletions(-)

diff --git a/code/compiler/13/llvm_context.cpp b/code/compiler/13/llvm_context.cpp
index 45dcb50..8416e4e 100644
--- a/code/compiler/13/llvm_context.cpp
+++ b/code/compiler/13/llvm_context.cpp
@@ -225,12 +225,7 @@ Value* llvm_context::unwrap_gmachine_stack_ptr(Value* g) {
 }
 
 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);
-    auto offset_0 = create_i32(0);
-    auto offset_1 = create_i32(1);
-    auto int_ptr = builder.CreateGEP(cast, { offset_0, offset_1 });
-    return builder.CreateLoad(int_ptr);
+    return builder.CreatePtrToInt(v, IntegerType::getInt32Ty(ctx));
 }
 Value* llvm_context::create_num(Function* f, Value* v) {
     auto alloc_num_f = functions.at("alloc_num");
diff --git a/code/compiler/13/runtime.c b/code/compiler/13/runtime.c
index 7b8a7c3..7d3b7b2 100644
--- a/code/compiler/13/runtime.c
+++ b/code/compiler/13/runtime.c
@@ -1,9 +1,13 @@
+#include <bits/stdint-intn.h>
 #include <stdint.h>
 #include <assert.h>
 #include <memory.h>
 #include <stdio.h>
 #include "runtime.h"
 
+#define INT_MARKER (1l << 63)
+#define IS_INT(n) ((uint64_t) n & INT_MARKER)
+
 struct node_base* alloc_node() {
     struct node_base* new_node = malloc(sizeof(struct node_app));
     new_node->gc_next = NULL;
@@ -21,10 +25,7 @@ struct node_app* alloc_app(struct node_base* l, struct node_base* r) {
 }
 
 struct node_num* alloc_num(int32_t n) {
-    struct node_num* node = (struct node_num*) alloc_node();
-    node->base.tag = NODE_NUM;
-    node->value = n;
-    return node;
+    return (struct node_num*) (INT_MARKER | n);
 }
 
 struct node_global* alloc_global(void (*f)(struct gmachine*), int32_t a) {
@@ -49,7 +50,7 @@ void free_node_direct(struct node_base* n) {
 }
 
 void gc_visit_node(struct node_base* n) {
-    if(n->gc_reachable) return;
+    if(IS_INT(n) || n->gc_reachable) return;
     n->gc_reachable = 1;
 
     if(n->tag == NODE_APP) {
@@ -169,6 +170,7 @@ void gmachine_split(struct gmachine* g, size_t n) {
 }
 
 struct node_base* gmachine_track(struct gmachine* g, struct node_base* b) {
+    if(IS_INT(b)) return b;
     g->gc_node_count++;
     b->gc_next = g->gc_nodes;
     g->gc_nodes = b;
@@ -208,7 +210,9 @@ void unwind(struct gmachine* g) {
 
     while(1) {
         struct node_base* peek = stack_peek(s, 0);
-        if(peek->tag == NODE_APP) {
+        if(IS_INT(peek)) {
+            break;
+        } else if(peek->tag == NODE_APP) {
             struct node_app* n = (struct node_app*) peek;
             stack_push(s, n->left);
         } else if(peek->tag == NODE_GLOBAL) {
@@ -234,7 +238,9 @@ void unwind(struct gmachine* g) {
 extern void f_main(struct gmachine* s);
 
 void print_node(struct node_base* n) {
-    if(n->tag == NODE_APP) {
+    if(IS_INT(n)) {
+        printf("%d", (int32_t) n);
+    } else if(n->tag == NODE_APP) {
         struct node_app* app = (struct node_app*) n;
         print_node(app->left);
         putchar(' ');
@@ -246,9 +252,6 @@ void print_node(struct node_base* n) {
         printf("(Global: %p)", global->function);
     } else if(n->tag == NODE_IND) {
         print_node(((struct node_ind*) n)->next);
-    } else if(n->tag == NODE_NUM) {
-        struct node_num* num = (struct node_num*) n;
-        printf("%d", num->value);
     }
 }