From 09a3e257e87045fd4c49d56b0e3459fe2f81d461 Mon Sep 17 00:00:00 2001
From: Bill Currie <bill@taniwha.org>
Date: Fri, 26 May 2023 21:56:19 +0900
Subject: [PATCH] [qfcc] Fully initialize local structural defs

I think the current build_element_chain implementation does a reasonable
job, but I'm in the process of getting designated initializers working,
thus it will become important to ensure uninitialized members get
initialized.
---
 tools/qfcc/include/expr.h         |  3 ++-
 tools/qfcc/source/expr.c          | 13 ++++++++++++-
 tools/qfcc/source/expr_compound.c | 21 +++++++++++++++++++++
 3 files changed, 35 insertions(+), 2 deletions(-)

diff --git a/tools/qfcc/include/expr.h b/tools/qfcc/include/expr.h
index 43dc6a255..b2b7631f3 100644
--- a/tools/qfcc/include/expr.h
+++ b/tools/qfcc/include/expr.h
@@ -142,7 +142,6 @@ typedef struct ex_memset_s {
 	struct expr_s *dst;
 	struct expr_s *val;
 	struct expr_s *count;
-	struct type_s *type;
 } ex_memset_t;
 
 /**	State expression used for think function state-machines.
@@ -778,6 +777,8 @@ expr_t *new_with_expr (int mode, int reg, expr_t *val);
 */
 expr_t *new_param_expr (struct type_s *type, int num);
 
+expr_t *new_memset_expr (expr_t *dst, expr_t *val, expr_t *count);
+
 /**	Convert a name to an expression of the appropriate type.
 
 	Converts the expression in-place. If the exprssion is not a name
diff --git a/tools/qfcc/source/expr.c b/tools/qfcc/source/expr.c
index deec20857..3e25ee5b1 100644
--- a/tools/qfcc/source/expr.c
+++ b/tools/qfcc/source/expr.c
@@ -140,7 +140,7 @@ get_type (expr_t *e)
 		case ex_with:
 			return &type_void;
 		case ex_memset:
-			return e->e.memset.type;
+			return 0;
 		case ex_error:
 			return 0;
 		case ex_return:
@@ -1374,6 +1374,17 @@ new_param_expr (type_t *type, int num)
 	return param_expr (va (0, ".param_%d", num), type);
 }
 
+expr_t *
+new_memset_expr (expr_t *dst, expr_t *val, expr_t *count)
+{
+	expr_t     *e = new_expr ();
+	e->type = ex_memset;
+	e->e.memset.dst = dst;
+	e->e.memset.val = val;
+	e->e.memset.count = count;
+	return e;
+}
+
 expr_t *
 append_expr (expr_t *block, expr_t *e)
 {
diff --git a/tools/qfcc/source/expr_compound.c b/tools/qfcc/source/expr_compound.c
index 2ba6f489a..eb5dafae8 100644
--- a/tools/qfcc/source/expr_compound.c
+++ b/tools/qfcc/source/expr_compound.c
@@ -42,6 +42,7 @@
 #include "QF/alloc.h"
 #include "QF/dstring.h"
 #include "QF/mathlib.h"
+#include "QF/set.h"
 #include "QF/sys.h"
 #include "QF/va.h"
 
@@ -189,6 +190,8 @@ assign_elements (expr_t *local_expr, expr_t *init,
 				 element_chain_t *element_chain)
 {
 	element_t  *element;
+	type_t     *init_type = get_type (init);
+	set_t      *initialized = set_new_size (type_size (init_type));
 
 	for (element = element_chain->head; element; element = element->next) {
 		int         offset = element->offset;
@@ -206,7 +209,25 @@ assign_elements (expr_t *local_expr, expr_t *init,
 			c = convert_nil (c, type);
 		}
 		append_expr (local_expr, assign_expr (alias, c));
+		set_add_range (initialized, offset, type_size (type));
 	}
+
+	unsigned    start = 0;
+	for (set_iter_t *in = set_first (initialized); in; in = set_next (in)) {
+		unsigned    end = in->element;
+		if (end > start) {
+			expr_t     *dst = new_offset_alias_expr (&type_int, init, start);
+			expr_t     *zero = new_int_expr (0);
+			expr_t     *count = new_int_expr (end - start);
+			append_expr (local_expr, new_memset_expr (dst, zero, count));
+		}
+		// skip over all the initialized locations
+		in = set_while (in);
+		if (in) {
+			start = in->element;
+		}
+	}
+	set_delete (initialized);
 }
 
 expr_t *