1 files changed, 56 insertions, 18 deletions

diff --git a/codegen.c b/codegen.c
index 79deb46..f9dbc15 100644
--- a/codegen.c
+++ b/codegen.c
@@ -35,20 +35,26 @@ static const struct storage_location MULDIV_OVERFLOW_LOC = {
 static struct scope* scope;
 static const struct fn_decl_node* active_fn;
 static unsigned long long branch_counter = 0;
+static unsigned long long loop_counter = 0;
 
-static void enter_scope(struct scope* child_scope) {
+static void enter_scope(
+    struct scope* child_scope,
+    unsigned long long bp_offset
+) {
     if (child_scope == NULL ||
             child_scope->next_out != scope)
         CGEN_PANIC("enter_scope: scopes are misaligned");
 
     scope = child_scope;
+    scope->bp_offset = bp_offset;
 }
 
-static void exit_scope(struct scope* child_scope) {
+static void exit_scope(struct scope* child_scope, bool save_bp_offset) {
     if (child_scope != scope || child_scope->next_out == NULL)
         CGEN_PANIC("exit_scope: scopes are misaligned");
 
     scope = child_scope->next_out;
+    if (save_bp_offset) scope->bp_offset = child_scope->bp_offset;
 }
 
 static struct lval_def allocate_register(const struct type_def* type) {
@@ -305,6 +311,11 @@ static struct var_def* emit_var_decl(
     const struct var_decl_node* node
 ) {
     struct lval_def var_dst = make_stack_lval(outfile, node->type.def_ref);
+
+    fprintf(outfile, "\t; '%s' lives in: ", node->def_ref->name);
+    emit_storage_loc(outfile, &var_dst.loc, var_dst.type->sz);
+    fprintf(outfile, "\n");
+
     struct var_def* var_def = node->def_ref;
     var_def->loc = var_dst.loc;
     return var_def;
@@ -562,39 +573,63 @@ static void emit_group_contents(FILE* outfile, const struct group_node* node) {
 }
 
 static void emit_group(FILE* outfile, const struct group_node* node) {
-    enter_scope(node->scope);
-    scope->bp_offset = scope->next_out->bp_offset; /* don't reset bp */
+    enter_scope(node->scope, scope->bp_offset);
 
     emit_group_contents(outfile, node);
 
     /* don't reset sp because alloca needs to work */
     scope->next_out->bp_offset = scope->bp_offset;
-    exit_scope(node->scope);
+    exit_scope(node->scope, true);
 }
 
 static void emit_if(FILE* outfile, const struct if_node* node) {
-    enter_scope(node->scope);
+    enter_scope(node->scope, scope->bp_offset);
 
     struct lval_def cond_result =
         allocate_temporary(outfile, node->cond->resolved_type);
     emit_expr(outfile, node->cond, &cond_result);
     emit_cmp_zero(outfile, &cond_result);
 
-    unsigned long long false_branch_num = branch_counter++;
-    fprintf(outfile, "\tjz branch%lld\n", false_branch_num);
+    unsigned long long branch_num = ++branch_counter;
+    fprintf(outfile, "\tjz branch_false@%lld\n", branch_num);
     emit_stmt(outfile, node->true_branch);
 
     if (node->false_branch == NULL) {
-        fprintf(outfile, "branch%lld:\n", false_branch_num);
+        fprintf(outfile, "branch_false@%lld:\n", branch_num);
     } else {
-        unsigned long long end_branch_num = branch_counter++;
-        fprintf(outfile, "\tjmp branch%lld\n", end_branch_num);
-        fprintf(outfile, "branch%lld:\n", false_branch_num);
+        fprintf(outfile, "\tjmp branch_done@%lld\n", branch_num);
+        fprintf(outfile, "branch_false@%lld:\n", branch_num);
         emit_stmt(outfile, node->false_branch);
-        fprintf(outfile, "branch%lld:\n", end_branch_num);
+        fprintf(outfile, "branch_done@%lld:\n", branch_num);
+    }
+
+    exit_scope(node->scope, true);
+}
+
+static void emit_loop(FILE* outfile, const struct loop_node* node) {
+    enter_scope(node->scope, scope->bp_offset);
+
+    if (node->init != NULL) emit_expr(outfile, node->init, NULL);
+
+    unsigned long long loop_num = ++loop_counter;
+    if (node->cond != NULL) {
+        struct lval_def cond_dst =
+            allocate_temporary(outfile, node->cond->resolved_type);
+        fprintf(outfile, "loop_head@%lld:\n", loop_num);
+        emit_expr(outfile, node->cond, &cond_dst);
+        emit_cmp_zero(outfile, &cond_dst);
+        fprintf(outfile, "\tjz loop_done@%lld\n", loop_num);
+    } else {
+        fprintf(outfile, "loop_head@%lld:\n", loop_num);
     }
 
-    exit_scope(node->scope);
+    emit_stmt(outfile, node->body);
+    if (node->incr != NULL) emit_expr(outfile, node->incr, NULL);
+
+    fprintf(outfile, "\tjmp loop_head@%lld\n", loop_num);
+    fprintf(outfile, "loop_done@%lld:\n", loop_num);
+
+    exit_scope(node->scope, true);
 }
 
 static void emit_stmt(FILE* outfile, const struct stmt_node* node) {
@@ -616,11 +651,14 @@ static void emit_stmt(FILE* outfile, const struct stmt_node* node) {
         case STMT_IF:
             emit_if(outfile, &node->inner.if_);
             break;
+        case STMT_LOOP:
+            emit_loop(outfile, &node->inner.loop);
+            break;
     }
 }
 
 static void emit_fn_decl(FILE* outfile, const struct fn_decl_node* node) {
-    enter_scope(node->scope);
+    enter_scope(node->scope, 0);
 
     if (active_fn != NULL)
         CGEN_PANIC(
@@ -660,9 +698,9 @@ static void emit_fn_decl(FILE* outfile, const struct fn_decl_node* node) {
         emit_mov(outfile, &arg_dst, &arg_src);
     }
 
-    enter_scope(node->body.scope);
+    enter_scope(node->body.scope, scope->bp_offset);
     emit_group_contents(outfile, &node->body);
-    exit_scope(node->body.scope);
+    exit_scope(node->body.scope, true);
 
     fprintf(outfile, RETURN_LABEL_FMT ":\n", node->name);
     fprintf(outfile, "\tmov rsp, rbp\n");
@@ -670,7 +708,7 @@ static void emit_fn_decl(FILE* outfile, const struct fn_decl_node* node) {
     fprintf(outfile, "\tret\n");
 
     active_fn = NULL;
-    exit_scope(node->scope);
+    exit_scope(node->scope, false);
 }
 
 static void emit_root_node(FILE* outfile, const struct root_node* node) {