From d9371722430206706cd8b8592b89064ceab91f43 Mon Sep 17 00:00:00 2001
From: Bill Currie <bill@taniwha.org>
Date: Thu, 3 Mar 2011 13:46:07 +0900
Subject: [PATCH] Create and use alias operands for alias expressions.

This avoids the alias expression modifying the operand used in other
expressions.
---
 tools/qfcc/include/statements.h |  2 ++
 tools/qfcc/source/dot_flow.c    |  2 ++
 tools/qfcc/source/emit.c        |  4 ++++
 tools/qfcc/source/statements.c  | 13 ++++++++-----
 4 files changed, 16 insertions(+), 5 deletions(-)

diff --git a/tools/qfcc/include/statements.h b/tools/qfcc/include/statements.h
index 3352462b7..d4b5da79a 100644
--- a/tools/qfcc/include/statements.h
+++ b/tools/qfcc/include/statements.h
@@ -37,6 +37,7 @@ typedef enum {
 	op_label,
 	op_temp,
 	op_pointer,
+	op_alias,
 } op_type_e;
 
 typedef struct operand_s {
@@ -49,6 +50,7 @@ typedef struct operand_s {
 		struct ex_label_s *label;
 		struct ex_pointer_s *pointer;
 		struct def_s   *def;
+		struct operand_s *alias;
 	} o;
 } operand_t;
 
diff --git a/tools/qfcc/source/dot_flow.c b/tools/qfcc/source/dot_flow.c
index 1a0cf6c7c..89c33a2bc 100644
--- a/tools/qfcc/source/dot_flow.c
+++ b/tools/qfcc/source/dot_flow.c
@@ -146,6 +146,8 @@ get_operand (operand_t *op)
 				return va ("(%s)[%d]",
 						   type ? pr_type_name[type->type] : "???",
 						   op->o.pointer->val);
+		case op_alias:
+			return get_operand (op->o.alias);//FIXME better output
 	}
 	return ("??");
 }
diff --git a/tools/qfcc/source/emit.c b/tools/qfcc/source/emit.c
index bcd76b14a..630bb3cc9 100644
--- a/tools/qfcc/source/emit.c
+++ b/tools/qfcc/source/emit.c
@@ -125,6 +125,10 @@ get_operand_def (expr_t *expr, operand_t *op)
 				def->offset_reloc = 1;
 			}
 			return def;
+		case op_alias:
+			def = alias_def (get_operand_def (expr, op->o.alias),
+							 ev_types[op->type]);
+			return def;
 	}
 	return 0;
 }
diff --git a/tools/qfcc/source/statements.c b/tools/qfcc/source/statements.c
index a1760d2c4..ebb98aa61 100644
--- a/tools/qfcc/source/statements.c
+++ b/tools/qfcc/source/statements.c
@@ -115,6 +115,11 @@ print_operand (operand_t *op)
 			break;
 		case op_pointer:
 			printf ("ptr %p", op->o.pointer);
+			break;
+		case op_alias:
+			printf ("alias %s ", pr_type_name[op->type]);
+			print_operand (op->o.alias);
+			break;
 	}
 }
 
@@ -554,11 +559,9 @@ expr_expr (sblock_t *sblock, expr_t *e, operand_t **op)
 static sblock_t *
 expr_alias (sblock_t *sblock, expr_t *e, operand_t **op)
 {
-	operand_t  *src = 0;
-
-	sblock = statement_subexpr (sblock, e->e.expr.e1, &src);
-	src->type = low_level_type (e->e.expr.type);
-	*op = src;
+	*op = new_operand (op_alias);
+	(*op)->type = low_level_type (e->e.expr.type);
+	sblock = statement_subexpr (sblock, e->e.expr.e1, &(*op)->o.alias);
 	return sblock;
 }