From 3272b5d83d2e2167eed24748557df88bd66584ee Mon Sep 17 00:00:00 2001
From: tomsmeding <tom.smeding@gmail.com>
Date: Fri, 5 Jan 2018 23:42:24 +0100
Subject: There's actually a chance that, correctly stringified, this will work

---
 .gitignore    |  2 ++
 Makefile      |  5 ++++
 c.y           |  5 +++-
 compiler.c    | 95 +++++++++++++++++++++++++++++++++++++++++++++++------------
 ir.c          | 79 +++++++++++++++++++++++++++++++++++++++++--------
 ir.h          | 19 ++++++++----
 main.c        | 11 +++++--
 node.c        |  5 ++--
 node.h        |  5 +++-
 regalloc.c    | 33 +++++++++++++++++++++
 regalloc.h    | 19 ++++++++++++
 test/t1.c     |  3 +-
 to_assembly.c | 71 ++++++++++++++++++++++++++++++++++++++++++++
 to_assembly.h |  7 +++++
 14 files changed, 316 insertions(+), 43 deletions(-)
 create mode 100644 regalloc.c
 create mode 100644 regalloc.h
 create mode 100644 to_assembly.c
 create mode 100644 to_assembly.h

diff --git a/.gitignore b/.gitignore
index b711b6b..a5e0538 100644
--- a/.gitignore
+++ b/.gitignore
@@ -2,3 +2,5 @@ as1
 as2
 bison-out
 ccomp
+*.dSYM
+old/
diff --git a/Makefile b/Makefile
index e206eea..411fbf3 100644
--- a/Makefile
+++ b/Makefile
@@ -5,6 +5,11 @@ YAXX = bison
 CFLAGS = -Wall -Wextra -std=c11 -g -I. -D_GNU_SOURCE
 LDFLAGS = -lfl
 
+ifeq ($(shell uname), Darwin)
+	LDFLAGS += -L/usr/local/opt/flex/lib
+	CFLAGS += -I/usr/local/opt/flex/include
+endif
+
 TARGET = ccomp
 
 .PHONY: all clean
diff --git a/c.y b/c.y
index 5aafe26..ee98fe7 100644
--- a/c.y
+++ b/c.y
@@ -142,8 +142,11 @@ matched_statement:
 
 other_statement:
                 var_decl | expression ';' | block
+                | RETURN ';' {
+                    $$ = node_make_0(N_RETURN);
+                }
                 | RETURN expression ';' {
-                    $$ = node_make_1(N_RETURN, $2);
+                    $$ = node_make_1(N_RETURNV, $2);
                 } ;
 
 expression:     atom_expr
diff --git a/compiler.c b/compiler.c
index 34372f3..ea9f768 100644
--- a/compiler.c
+++ b/compiler.c
@@ -32,7 +32,7 @@ static bool oper_is_comparison(enum operator oper) {
 static struct ref compile_expr(struct ir *ir, struct symtab *symtab, struct node *node);
 
 static void compile_boolexpr(
-		struct ir *ir, struct symtab *symtab, struct node *node, char *truedest, char *falsedest) {
+		struct ir *ir, struct symtab *symtab, struct node *node, const char *truedest, const char *falsedest) {
 
 	if (node->type == N_BINOP && oper_is_comparison(node->oper)) {
 		struct ref r1 = compile_expr(ir, symtab, node->child1);
@@ -51,12 +51,12 @@ static void compile_boolexpr(
 		ir_append(ir, irins_make_jcc(falsedest, condcode));
 		ir_append(ir, irins_make_name(INS_JMP, truedest));
 	} else if (node->type == N_BINOP && node->oper == OP_AND) {
-		char *try2lbl = gen_label_name();
+		const char *try2lbl = gen_label_name();
 		compile_boolexpr(ir, symtab, node->child1, try2lbl, falsedest);
 		ir_append(ir, irins_make_name(INS_LBL, try2lbl));
 		compile_boolexpr(ir, symtab, node->child2, truedest, falsedest);
 	} else if (node->type == N_BINOP && node->oper == OP_OR) {
-		char *try2lbl = gen_label_name();
+		const char *try2lbl = gen_label_name();
 		compile_boolexpr(ir, symtab, node->child1, truedest, try2lbl);
 		ir_append(ir, irins_make_name(INS_LBL, try2lbl));
 		compile_boolexpr(ir, symtab, node->child2, truedest, falsedest);
@@ -108,9 +108,9 @@ static struct ref compile_expr(struct ir *ir, struct symtab *symtab, struct node
 				ir_append(ir, irins_make_012(instype, r0, r1, r2));
 				return r0;
 			} else if (oper_is_comparison(node->oper) || node->oper == OP_AND || node->oper == OP_OR) {
-				char *truelbl = gen_label_name();
-				char *falselbl = gen_label_name();
-				char *afterlbl = gen_label_name();
+				const char *truelbl = gen_label_name();
+				const char *falselbl = gen_label_name();
+				const char *afterlbl = gen_label_name();
 				compile_boolexpr(ir, symtab, node, truelbl, falselbl);
 				struct ref cval = ref_next_register();
 				ir_append(ir, irins_make_name(INS_LBL, truelbl));
@@ -207,7 +207,7 @@ static struct ref compile_expr(struct ir *ir, struct symtab *symtab, struct node
 			} else {
 				retref = ref_next_register();
 				struct irins *ins = irins_make_0(INS_CALLV, retref);
-				ins->name = strdup(node->name);
+				ins->name = ir_str(node->name);
 				ir_append(ir, ins);
 			}
 			ir_append(ir, irins_make_012(INS_ADD, ref_reg(REG_SP), ref_reg(REG_SP), ref_imm(sym->numparams)));
@@ -246,38 +246,50 @@ static void compile_node(struct ir *ir, struct symtab *symtab, struct node *node
 			struct ref vref;
 			if (node->type == N_VAR_DECL_INIT) vref = compile_expr(ir, symtab, node->child1);
 			else vref = ref_imm(0);
-			struct symbol *sym = symbol_make_var(node->name, node->rtype);
-			sym->ref = ref_next_register();
+			struct symbol *sym = symbol_make_var(strdup(node->name), node->rtype);
+			if (symtab->parent == NULL) sym->ref = ir_reserve_global(ir, 1);
+			else sym->ref = ref_next_register();
 			symtab_insert(symtab, sym);
 			ir_append(ir, irins_make_01(INS_MOV, sym->ref, vref));
 			break;
 		}
 
 		case N_FUNC_DECL: {
+			if (memcmp(node->name, "__", 2) == 0) {
+				fprintf(stderr, "Invalid function name '%s' (cannot start with '__')\n", node->name);
+				exit(1);
+			}
 			if (symtab_find(symtab, node->name)) {
 				fprintf(stderr, "Redeclaration of function '%s'\n", node->name);
 				exit(1);
 			}
 			int numparams = node_list_length(node->child1);
-			struct symbol *sym = symbol_make_func(node->name, node->rtype, numparams);
+			struct symbol *sym = symbol_make_func(strdup(node->name), node->rtype, numparams);
 			write_func_params(sym->params, node->child1);
 			symtab_insert(symtab_root(symtab), sym);
-			ir_append(ir, irins_make_name(INS_LBL, strdup(node->name)));
+
+			ir_append(ir, irins_make_name(INS_LBL, node->name));
+
 			symtab = symtab_sub(symtab);
 			for (int i = 0; i < numparams; i++) {
-				struct symbol *parsym = symbol_make_var(sym->params[i].name, sym->params[i].type);
+				struct symbol *parsym = symbol_make_var(strdup(sym->params[i].name), sym->params[i].type);
 				parsym->ref = ref_mem(REG_BP, -2 - i, REFREL_ZERO);
 				symtab_insert(symtab, parsym);
 			}
+
 			compile_node(ir, symtab, node->child2);
+
 			symtab = symtab_delete_get_parent(symtab);
+
+			// necessary for void functions, to be sure otherwise
+			ir_append(ir, irins_make(INS_RET));
 			break;
 		}
 
 		case N_IF: {
-			char *thenlbl = gen_label_name();
-			char *elselbl = gen_label_name();
-			char *afterlbl = gen_label_name();
+			const char *thenlbl = gen_label_name();
+			const char *elselbl = gen_label_name();
+			const char *afterlbl = gen_label_name();
 			compile_boolexpr(ir, symtab, node->child1, thenlbl, elselbl);
 			ir_append(ir, irins_make_name(INS_LBL, thenlbl));
 			compile_node(ir, symtab, node->child2);
@@ -289,9 +301,9 @@ static void compile_node(struct ir *ir, struct symtab *symtab, struct node *node
 		}
 
 		case N_WHILE: {
-			char *startlbl = gen_label_name();
-			char *bodylbl = gen_label_name();
-			char *afterlbl = gen_label_name();
+			const char *startlbl = gen_label_name();
+			const char *bodylbl = gen_label_name();
+			const char *afterlbl = gen_label_name();
 			ir_append(ir, irins_make_name(INS_LBL, startlbl));
 			compile_boolexpr(ir, symtab, node->child1, bodylbl, afterlbl);
 			ir_append(ir, irins_make_name(INS_LBL, bodylbl));
@@ -301,7 +313,11 @@ static void compile_node(struct ir *ir, struct symtab *symtab, struct node *node
 			break;
 		}
 
-		case N_RETURN: {
+		case N_RETURN:
+			ir_append(ir, irins_make(INS_RET));
+			break;
+
+		case N_RETURNV: {
 			struct ref ref = compile_expr(ir, symtab, node->child1);
 			ir_append(ir, irins_make_1(INS_RETV, ref));
 			break;
@@ -313,9 +329,50 @@ static void compile_node(struct ir *ir, struct symtab *symtab, struct node *node
 	}
 }
 
+static void compile_data_setup_node(struct ir *ir, struct symtab *symtab, struct node *node) {
+	switch (node->type) {
+		case N_LIST:
+			if (node->child1->type == N_VAR_DECL || node->child1->type == N_VAR_DECL_INIT) {
+				compile_node(ir, symtab, node->child1);
+				node_delete_recursive(node->child1);
+				node->child1 = node_make_0(N_LIST_END);
+			}
+			compile_data_setup_node(ir, symtab, node->child2);
+			break;
+
+		case N_LIST_END:
+			break;
+
+		case N_VAR_DECL:
+		case N_VAR_DECL_INIT:
+			compile_node(ir, symtab, node);
+			break;
+
+		case N_FUNC_DECL:
+			break;
+
+		default:
+			assert(false);
+	}
+}
+
+static void compile_data_setup(struct ir *ir, struct symtab *symtab, struct node *root) {
+	struct ref flag = ir_reserve_global(ir, 1);
+	ir_append(ir, irins_make_12(INS_TEST, flag, flag));
+	const char *afterlbl = gen_label_name();
+	ir_append(ir, irins_make_jcc(afterlbl, CCNZ));
+
+	compile_data_setup_node(ir, symtab, root);
+
+	ir_append(ir, irins_make_name(INS_LBL, afterlbl));
+	ir_append(ir, irins_make_name(INS_CALL, "main"));
+	ir_append(ir, irins_make(INS_BRK));
+}
+
 struct ir* compile(struct node *node) {
 	struct ir *ir = ir_make();
 	struct symtab *symtab = symtab_make();
+	compile_data_setup(ir, symtab, node);
 	compile_node(ir, symtab, node);
 	return ir;
 }
diff --git a/ir.c b/ir.c
index cf529dd..69a9d64 100644
--- a/ir.c
+++ b/ir.c
@@ -1,8 +1,29 @@
 #include <stdlib.h>
+#include <string.h>
 #include <assert.h>
 #include "ir.h"
 
 
+static int cap_interned = 32;
+static int num_interned = 0;
+static char **interned_strings = NULL;
+
+const char* ir_str(const char *str) {
+	if (interned_strings == NULL) {
+		interned_strings = malloc(cap_interned * sizeof(char*));
+	}
+	for (int i = 0; i < num_interned; i++) {
+		if (strcmp(interned_strings[i], str) == 0) return interned_strings[i];
+	}
+	if (num_interned == cap_interned) {
+		cap_interned *= 2;
+		interned_strings = realloc(interned_strings, cap_interned * sizeof(char*));
+	}
+	interned_strings[num_interned++] = strdup(str);
+	return interned_strings[num_interned - 1];
+}
+
+
 struct ir* ir_make(void) {
 	struct ir *ir = malloc(sizeof(struct ir));
 	ir->cap = 32;
@@ -90,7 +111,7 @@ void irins_print(struct irins *ins, FILE *f) {
 		case INS_NOT: fprintf(f, "\t%s <- !%s\n", ref_show(ins->r0), ref_show(ins->r1)); break;
 		case INS_TEST: fprintf(f, "\ttest %s, %s\n", ref_show(ins->r1), ref_show(ins->r2)); break;
 		case INS_PUSH: fprintf(f, "\tpush %s\n", ref_show(ins->r1)); break;
-		case INS_POP: fprintf(f, "\t%s = pop\n", ref_show(ins->r0)); break;
+		case INS_POP: fprintf(f, "\t%s <- pop\n", ref_show(ins->r0)); break;
 		case INS_CMP: fprintf(f, "\tcmp %s, %s\n", ref_show(ins->r1), ref_show(ins->r2)); break;
 		case INS_LBL: fprintf(f, "%s:\n", ins->name); break;
 		case INS_JMP: fprintf(f, "\tjmp %s\n", ins->name); break;
@@ -100,6 +121,7 @@ void irins_print(struct irins *ins, FILE *f) {
 		case INS_RET: fprintf(f, "\tret\n"); break;
 		case INS_RETV: fprintf(f, "\tret %s\n", ref_show(ins->r1)); break;
 		case INS_MOV: fprintf(f, "\t%s <- %s\n", ref_show(ins->r0), ref_show(ins->r1)); break;
+		case INS_BRK: fprintf(f, "\tbrk\n"); break;
 		default: assert(false);
 	}
 }
@@ -110,12 +132,19 @@ struct ref ir_reserve_global(struct ir *ir, int size) {
 	return ref_mem(REG_UNUSED, offset, REFREL_DATA);
 }
 
-void ir_append(struct ir *ir, struct irins *ins) {
+void ir_insert_before(struct ir *ir, int pos, struct irins *ins) {
+	assert(pos >= 0 && pos <= ir->len);
 	if (ir->len == ir->cap) {
 		ir->cap *= 2;
 		ir->inss = realloc(ir->inss, ir->cap * sizeof(struct irins*));
 	}
-	ir->inss[ir->len++] = ins;
+	memmove(ir->inss + pos + 1, ir->inss + pos, (ir->len - pos) * sizeof(struct irins*));
+	ir->inss[pos] = ins;
+	ir->len++;
+}
+
+void ir_append(struct ir *ir, struct irins *ins) {
+	ir_insert_before(ir, ir->len, ins);
 }
 
 struct irins* irins_make(enum instype type) {
@@ -125,9 +154,9 @@ struct irins* irins_make(enum instype type) {
 	return ins;
 }
 
-struct irins* irins_make_name(enum instype type, char *name) {
+struct irins* irins_make_name(enum instype type, const char *name) {
 	struct irins *ins = irins_make(type);
-	ins->name = name;
+	ins->name = ir_str(name);
 	return ins;
 }
 
@@ -163,23 +192,49 @@ struct irins* irins_make_12(enum instype type, struct ref r1, struct ref r2) {
 	return ins;
 }
 
-struct irins* irins_make_jcc(char *name, enum condcode condcode) {
+struct irins* irins_make_jcc(const char *name, enum condcode condcode) {
 	struct irins *ins = irins_make(INS_JCC);
-	ins->name = name;
+	ins->name = ir_str(name);
 	ins->condcode = condcode;
 	return ins;
 }
 
 void irins_delete(struct irins *ins) {
-	if (ins->name) free(ins->name);
 	free(ins);
 }
 
-char* gen_label_name(void) {
+void irins_which_refs(const struct irins *ins, bool have[3]) {
+	have[0] = false; have[1] = false; have[2] = false;
+	switch (ins->type) {
+		case INS_ADD: have[0] = true; have[1] = true; have[2] = true; break;
+		case INS_SUB: have[0] = true; have[1] = true; have[2] = true; break;
+		case INS_MUL: have[0] = true; have[1] = true; have[2] = true; break;
+		case INS_DIV: have[0] = true; have[1] = true; have[2] = true; break;
+		case INS_MOD: have[0] = true; have[1] = true; have[2] = true; break;
+		case INS_NEG: have[0] = true; have[1] = true; break;
+		case INS_NOT: have[0] = true; have[1] = true; break;
+		case INS_TEST: have[1] = true; have[2] = true; break;
+		case INS_PUSH: have[1] = true; break;
+		case INS_POP: have[0] = true; break;
+		case INS_CMP: have[1] = true; have[2] = true; break;
+		case INS_LBL: break;
+		case INS_JMP: break;
+		case INS_JCC: break;
+		case INS_CALL: break;
+		case INS_CALLV: have[0] = true; break;
+		case INS_RET: break;
+		case INS_RETV: have[1] = true; break;
+		case INS_MOV: have[0] = true; have[1] = true; break;
+		case INS_BRK: break;
+		default: assert(false);
+	}
+}
+
+const char* gen_label_name(void) {
 	static int next = 0;
-	char *buf = malloc(16);
-	sprintf(buf, "L%d", next++);
-	return buf;
+	static char buf[16];
+	sprintf(buf, "__L%d", next++);
+	return ir_str(buf);
 }
 
 struct ref ref_reg(int reg) {
diff --git a/ir.h b/ir.h
index e732a3d..5d92eed 100644
--- a/ir.h
+++ b/ir.h
@@ -26,6 +26,7 @@ enum instype {
 	INS_RET,   // return
 	INS_RETV,  // return r1
 	INS_MOV,   // r0 = r1
+	INS_BRK,   // halt
 };
 
 enum condcode {
@@ -64,8 +65,11 @@ struct ref {
 
 struct irins {
 	enum instype type;
-	struct ref r0, r1, r2;
-	char *name;
+	union {
+		struct ref three_refs[3];
+		struct {struct ref r0, r1, r2;};
+	};
+	const char *name;  // should be a return value from ir_str()
 	enum condcode condcode;
 };
 
@@ -82,22 +86,27 @@ void ir_delete(struct ir *ir);
 void ir_print(struct ir *ir, FILE *f);
 void irins_print(struct irins *ins, FILE *f);
 
+const char* ir_str(const char *str);  // returns interned string
+
 // returns offset in .data segment
 struct ref ir_reserve_global(struct ir *ir, int size);
 
+void ir_insert_before(struct ir *ir, int pos, struct irins *ins);
 void ir_append(struct ir *ir, struct irins *ins);
 
 struct irins* irins_make(enum instype type);
-struct irins* irins_make_name(enum instype type, char *name);
+struct irins* irins_make_name(enum instype type, const char *name);
 struct irins* irins_make_0(enum instype type, struct ref r0);
 struct irins* irins_make_01(enum instype type, struct ref r0, struct ref r1);
 struct irins* irins_make_012(enum instype type, struct ref r0, struct ref r1, struct ref r2);
 struct irins* irins_make_1(enum instype type, struct ref r1);
 struct irins* irins_make_12(enum instype type, struct ref r1, struct ref r2);
-struct irins* irins_make_jcc(char *name, enum condcode condcode);
+struct irins* irins_make_jcc(const char *name, enum condcode condcode);
 void irins_delete(struct irins *ins);
 
-char* gen_label_name(void);
+void irins_which_refs(const struct irins *ins, bool haveref[3]);
+
+const char* gen_label_name(void);
 
 struct ref ref_reg(int reg);
 struct ref ref_mem(int reg, int offset, enum refrel rel);
diff --git a/main.c b/main.c
index 7577012..5588543 100644
--- a/main.c
+++ b/main.c
@@ -3,6 +3,8 @@
 #include <assert.h>
 #include "compiler.h"
 #include "node.h"
+#include "regalloc.h"
+#include "to_assembly.h"
 
 
 extern FILE *yyin;
@@ -30,9 +32,14 @@ int main(int argc, char **argv) {
 	printf("\n");
 
 	struct ir *ir = compile(root_node);
-	ir_print(ir, stdout);
 
-	type_cache_cleanup();
+	ir_print(ir, stdout); printf("\n");
+
+	struct allocation *alloc = regalloc(ir);
+	to_assembly(ir, alloc);
+	allocation_delete(alloc);
+
+	ir_print(ir, stdout); printf("\n");
 
 	return result;
 }
diff --git a/node.c b/node.c
index b20c38e..f34061c 100644
--- a/node.c
+++ b/node.c
@@ -66,7 +66,7 @@ static void write_spaces(int num, FILE *f) {
 	for (int i = 0; i < num; i++) fputc(' ', f);
 }
 
-static const char* node_type_string(enum node_type type) {
+const char* node_type_string(enum node_type type) {
 	switch (type) {
 		case N_LIST: return "N_LIST"; break;
 		case N_LIST_END: return "N_LIST_END"; break;
@@ -79,6 +79,7 @@ static const char* node_type_string(enum node_type type) {
 		case N_IF: return "N_IF"; break;
 		case N_WHILE: return "N_WHILE"; break;
 		case N_RETURN: return "N_RETURN"; break;
+		case N_RETURNV: return "N_RETURNV"; break;
 		case N_BINOP: return "N_BINOP"; break;
 		case N_UNOP: return "N_UNOP"; break;
 		case N_CALL: return "N_CALL"; break;
@@ -86,7 +87,7 @@ static const char* node_type_string(enum node_type type) {
 	}
 }
 
-static const char* oper_string(enum operator oper) {
+const char* oper_string(enum operator oper) {
 	switch (oper) {
 		case OP_ADD: return "OP_ADD";
 		case OP_SUB: return "OP_SUB";
diff --git a/node.h b/node.h
index 81d0b26..f98257f 100644
--- a/node.h
+++ b/node.h
@@ -12,7 +12,8 @@ enum node_type {
 	N_FUNC_DECL,  // rtype name [params] [body]
 	N_IF,  // [cond] [body] [else-body]
 	N_WHILE,  // [cond] [body]
-	N_RETURN,  // [value]
+	N_RETURN,  // --
+	N_RETURNV,  // [value]
 	N_NUM,  // value
 	N_VAR,  // name
 	N_BINOP,  // [left] oper [right]
@@ -53,4 +54,6 @@ int node_list_length(struct node *node);
 
 void node_delete_recursive(struct node *node);
 
+const char* node_type_string(enum node_type type);
+const char* oper_string(enum operator oper);
 void node_print(const struct node *node, FILE *f, int indent);
diff --git a/regalloc.c b/regalloc.c
new file mode 100644
index 0000000..cf6e595
--- /dev/null
+++ b/regalloc.c
@@ -0,0 +1,33 @@
+#include <stdlib.h>
+#include <assert.h>
+#include "regalloc.h"
+
+
+struct allocation* regalloc(const struct ir *ir) {
+	int maxreg = 0;
+	for (int i = 0; i < ir->len; i++) {
+		const struct irins *ins = ir->inss[i];
+
+		bool haveref[3];
+		irins_which_refs(ins, haveref);
+		for (int ri = 0; ri < 3; ri++) {
+			if (haveref[ri] && ins->three_refs[ri].reg > maxreg) {
+				maxreg = ins->three_refs[ri].reg;
+			}
+		}
+	}
+
+	struct allocation *alloc = malloc(sizeof(struct allocation));
+	alloc->numregs = maxreg + 1;
+	alloc->allocs = malloc(alloc->numregs * sizeof(struct allocation_record));
+	for (int i = 0; i < alloc->numregs; i++) {
+		alloc->allocs[i].spill = true;  // lel
+	}
+
+	return alloc;
+}
+
+void allocation_delete(struct allocation *alloc) {
+	free(alloc->allocs);
+	free(alloc);
+}
diff --git a/regalloc.h b/regalloc.h
new file mode 100644
index 0000000..6ba0470
--- /dev/null
+++ b/regalloc.h
@@ -0,0 +1,19 @@
+#pragma once
+
+#include <stdbool.h>
+#include "ir.h"
+
+
+struct allocation_record {
+	bool spill;
+	int reg;  // only used if spill == false
+};
+
+struct allocation {
+	int numregs;
+	struct allocation_record *allocs;
+};
+
+struct allocation* regalloc(const struct ir *ir);
+
+void allocation_delete(struct allocation *alloc);
diff --git a/test/t1.c b/test/t1.c
index 33890fb..35a5312 100644
--- a/test/t1.c
+++ b/test/t1.c
@@ -14,8 +14,9 @@ int fibo(int n) {
 	return b;
 }
 
-int main(int argc, int **argv) {
+void main(int argc, int **argv) {
 	int a = 1;
 	int b = 2 + a * 3;
+	fibo(5);
 	// holo_dec(a);
 }
diff --git a/to_assembly.c b/to_assembly.c
new file mode 100644
index 0000000..ab5c845
--- /dev/null
+++ b/to_assembly.c
@@ -0,0 +1,71 @@
+#include <string.h>
+#include "to_assembly.h"
+
+
+static bool is_function_label(const char *lbl) {
+	return memcmp(lbl, "__", 2) != 0;
+}
+
+static void fix_everything(struct ir *ir, const int startidx, struct allocation *ral) {
+	int spillspace = 0;
+
+	for (int idx = startidx + 1; idx < ir->len; idx++) {
+		struct irins *ins = ir->inss[idx];
+
+		if (ins->type == INS_LBL && is_function_label(ins->name)) break;
+
+		if (ins->type == INS_CALLV) {
+			ins->type = INS_CALL;
+			ir_insert_before(ir, idx + 1, irins_make_01(INS_MOV, ins->r0, ref_reg(REG_A)));
+			idx--;
+			continue;
+		}
+		if (ins->type == INS_RETV) {
+			ir_insert_before(ir, idx, irins_make_01(INS_MOV, ref_reg(REG_A), ins->r1));
+			ins->type = INS_RET;
+			idx--;
+			continue;
+		}
+
+		bool haveref[3];
+		irins_which_refs(ins, haveref);
+		for (int ri = 0; ri < 3; ri++) {
+			struct ref *ref = &ins->three_refs[ri];
+			if (haveref[ri] && ref->type == REF_REG && ref->reg >= 0) {
+				if (ral->allocs[ref->reg].spill) {
+					*ref = ref_mem(REG_BP, spillspace + 1, REFREL_ZERO);
+					spillspace++;
+				} else {
+					ref->reg = ral->allocs[ref->reg].reg;
+				}
+			}
+		}
+	}
+	
+	if (spillspace == 0) return;
+
+	ir_insert_before(ir, startidx + 1, irins_make_1(INS_PUSH, ref_reg(REG_BP)));
+	ir_insert_before(ir, startidx + 2, irins_make_01(INS_MOV, ref_reg(REG_BP), ref_reg(REG_SP)));
+	ir_insert_before(ir, startidx + 3,
+			irins_make_012(INS_SUB, ref_reg(REG_SP), ref_reg(REG_SP), ref_imm(spillspace)));
+
+	for (int idx = startidx + 1; idx < ir->len; idx++) {
+		struct irins *ins = ir->inss[idx];
+
+		if (ins->type == INS_LBL && is_function_label(ins->name)) break;
+
+		if (ins->type == INS_RET) {
+			ir_insert_before(ir, idx++, irins_make_01(INS_MOV, ref_reg(REG_SP), ref_reg(REG_BP)));
+			ir_insert_before(ir, idx++, irins_make_0(INS_POP, ref_reg(REG_BP)));
+			continue;
+		}
+	}
+}
+
+void to_assembly(struct ir *ir, struct allocation *ral) {
+	for (int idx = 0; idx < ir->len; idx++) {
+		if (ir->inss[idx]->type == INS_LBL && is_function_label(ir->inss[idx]->name)) {
+			fix_everything(ir, idx, ral);
+		}
+	}
+}
diff --git a/to_assembly.h b/to_assembly.h
new file mode 100644
index 0000000..d18c4b7
--- /dev/null
+++ b/to_assembly.h
@@ -0,0 +1,7 @@
+#pragma once
+
+#include "ir.h"
+#include "regalloc.h"
+
+
+void to_assembly(struct ir *ir, struct allocation *ral);
-- 
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