start codegen work

1 files changed, 108 insertions, 0 deletions

diff --git a/codegen.c b/codegen.c
new file mode 100644
index 0000000..37c7a91
--- /dev/null
+++ b/codegen.c
@@ -0,0 +1,108 @@
+#include "ccc.h"
+#include "ast.h"
+#include <stdlib.h>
+#include <stdio.h>
+
+static void emit_stmt(FILE* outfile, const struct stmt_node* node);
+static void emit_expr(
+    FILE* outfile,
+    const struct expr_node* node,
+    const char* reg);
+
+static void emit_int_lit(
+    FILE* outfile,
+    const struct int_lit_node* node,
+    const char* reg
+) {
+   fprintf(outfile, "\tmov %s, %lld\n", reg, node->val); 
+}
+
+static void emit_expr(
+    FILE* outfile,
+    const struct expr_node* node,
+    const char* reg
+) {
+    switch (node->type) {
+        case EXPR_EMPTY:
+            break;
+        case EXPR_INT_LIT:
+            emit_int_lit(outfile, &node->as._int_lit, reg);
+            break;
+    }
+}
+
+static void emit_var_decl(FILE* outfile, const struct var_decl_node* node) {
+    /* TODO: make do smth */
+}
+
+static void emit_return(FILE* outfile, const struct return_node* node) {
+    if (node->ret_val != NULL) emit_expr(outfile, node->ret_val, "rax");
+    fprintf(outfile, "\tret\n");
+}
+
+static void emit_group(FILE* outfile, const struct group_node* node) {
+    const struct stmt_node* body_node = node->body_head;
+    while (body_node != NULL) {
+        emit_stmt(outfile, body_node);
+        body_node = body_node->next;
+    }
+}
+
+static void emit_stmt(FILE* outfile, const struct stmt_node* node) {
+    switch (node->type) {
+        case STMT_VAR_DECL:
+            emit_var_decl(outfile, &node->as._var_decl);
+            break;
+        case STMT_RETURN:
+            emit_return(outfile, &node->as._return);
+            break;
+        case STMT_EXPR:
+            emit_expr(outfile, &node->as._expr, NULL);
+            break;
+        case STMT_GROUP:
+            emit_group(outfile, &node->as._group);
+            break;
+    }
+}
+
+static void emit_fn_decl(FILE* outfile, const struct fn_decl_node* node) {
+    fprintf(outfile, "%s:\n", node->name);
+    /* TODO: probably something to map the args to temporaries lol */
+    emit_group(outfile, &node->body);
+}
+
+static void emit_root_node(FILE* outfile, const struct root_node* node) {
+    switch (node->type) {
+        case ROOT_FN_DECL:
+            emit_fn_decl(outfile, &node->as._fn_decl);
+            break;
+    }
+}
+
+void emit_code(const struct root_node* ast, const char* path) {
+    FILE* outfile = fopen(path, "w");
+    if (outfile == NULL) CCC_PANIC;
+
+    fprintf(outfile, "section .text\n");
+
+    /* output all non-static function declarations as globals */
+    const struct root_node* node = ast;
+    while (node != NULL) {
+        if (node->type == ROOT_FN_DECL)
+            fprintf(outfile, "global %s\n", node->as._fn_decl.name);
+
+        node = node->next;
+    }
+
+    fprintf(outfile, "\n");
+
+    /* actual code body */
+    node = ast;
+    while (node != NULL) {
+        emit_root_node(outfile, node);
+        fprintf(outfile, "\n");
+        node = node->next;
+    }
+
+    fclose(outfile);
+}