From 68bf013601a9d878861deec2e0a5095c367ee684 Mon Sep 17 00:00:00 2001
From: Bill Currie <bill@taniwha.org>
Date: Mon, 19 Nov 2012 15:18:31 +0900
Subject: [PATCH] Use a dag-local live vars set.

Function calls need to ensure .param_N actually get assigned, and so the
params must be seen as live by the dead variable removal code. However, it
is undesirable to modify the live vars data of the flow node, so make a
local copy.
---
 tools/qfcc/source/dags.c | 29 ++++++++++++++++++++++++++---
 1 file changed, 26 insertions(+), 3 deletions(-)

diff --git a/tools/qfcc/source/dags.c b/tools/qfcc/source/dags.c
index b1ef8c97a..f1d98c6a9 100644
--- a/tools/qfcc/source/dags.c
+++ b/tools/qfcc/source/dags.c
@@ -279,7 +279,7 @@ dagnode_attach_label (dagnode_t *n, daglabel_t *l)
 }
 
 static void
-dag_remove_dead_vars (dag_t *dag)
+dag_remove_dead_vars (dag_t *dag, set_t *live_vars)
 {
 	int         i;
 
@@ -292,7 +292,7 @@ dag_remove_dead_vars (dag_t *dag)
 		var = flow_get_var (l->op);
 		if (!var)
 			continue;
-		if (!set_is_member (dag->flownode->live_vars.out, var->number))
+		if (!set_is_member (live_vars, var->number))
 			set_remove (l->dagnode->identifiers, l->number);
 	}
 }
@@ -337,12 +337,15 @@ dag_create (flownode_t *flownode)
 	dagnode_t **nodes;
 	daglabel_t **labels;
 	int         num_statements = 0;
+	set_t      *live_vars = set_new ();
 
 	flush_daglabels ();
 
 	for (s = block->statements; s; s = s->next)
 		num_statements++;
 
+	set_assign (live_vars, flownode->live_vars.out);
+
 	dag = new_dag ();
 	dag->flownode = flownode;
 	// at most 4 per statement
@@ -404,6 +407,25 @@ dag_create (flownode_t *flownode)
 			lx->expr = s->expr;
 			dagnode_attach_label (n, lx);
 		}
+		if (n->type == st_func
+			&& (!strncmp (n->label->opcode, "<CALL", 5)
+				|| !strncmp (n->label->opcode, "<RCALL", 6))) {
+			int         start, end;
+
+			if (!strncmp (n->label->opcode, "<CALL", 5)) {
+				start = 0;
+				end = 0;
+				if (n->label->opcode[5] != '>')
+					end = n->label->opcode[5] - '0';
+			} else {
+				start = 2;
+				end = n->label->opcode[6] - '0';
+			}
+			while (start < end) {
+				set_add (live_vars, start + 1);
+				start++;
+			}
+		}
 	}
 
 	nodes = malloc (dag->num_nodes * sizeof (dagnode_t *));
@@ -413,8 +435,9 @@ dag_create (flownode_t *flownode)
 	memcpy (labels, dag->labels, dag->num_labels * sizeof (daglabel_t *));
 	dag->labels = labels;
 
-	dag_remove_dead_vars (dag);
+	dag_remove_dead_vars (dag, live_vars);
 	dag_sort_nodes (dag);
+	set_delete (live_vars);
 	return dag;
 }