From d88a117eaa39b1d0eb1a79fe84c81840a39eb233 Mon Sep 17 00:00:00 2001
From: Richard Henderson <richard.henderson@linaro.org>
Date: Mon, 26 Nov 2018 12:47:28 -0800
Subject: [PATCH] tcg: Reference count labels

Increment when adding branches, and decrement when removing them.

Reviewed-by: Emilio G. Cota <cota@braap.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 tcg/tcg-op.c |  2 ++
 tcg/tcg-op.h |  1 +
 tcg/tcg.c    | 20 ++++++++++++++++++++
 tcg/tcg.h    |  3 ++-
 4 files changed, 25 insertions(+), 1 deletion(-)

diff --git a/tcg/tcg-op.c b/tcg/tcg-op.c
index 38652db32c..1bd7ef24af 100644
--- a/tcg/tcg-op.c
+++ b/tcg/tcg-op.c
@@ -240,6 +240,7 @@ void tcg_gen_brcond_i32(TCGCond cond, TCGv_i32 arg1, TCGv_i32 arg2, TCGLabel *l)
     if (cond == TCG_COND_ALWAYS) {
         tcg_gen_br(l);
     } else if (cond != TCG_COND_NEVER) {
+        l->refs++;
         tcg_gen_op4ii_i32(INDEX_op_brcond_i32, arg1, arg2, cond, label_arg(l));
     }
 }
@@ -1405,6 +1406,7 @@ void tcg_gen_brcond_i64(TCGCond cond, TCGv_i64 arg1, TCGv_i64 arg2, TCGLabel *l)
     if (cond == TCG_COND_ALWAYS) {
         tcg_gen_br(l);
     } else if (cond != TCG_COND_NEVER) {
+        l->refs++;
         if (TCG_TARGET_REG_BITS == 32) {
             tcg_gen_op6ii_i32(INDEX_op_brcond2_i32, TCGV_LOW(arg1),
                               TCGV_HIGH(arg1), TCGV_LOW(arg2),
diff --git a/tcg/tcg-op.h b/tcg/tcg-op.h
index db4e9188f4..7007ec0d4d 100644
--- a/tcg/tcg-op.h
+++ b/tcg/tcg-op.h
@@ -260,6 +260,7 @@ static inline void gen_set_label(TCGLabel *l)
 
 static inline void tcg_gen_br(TCGLabel *l)
 {
+    l->refs++;
     tcg_gen_op1(INDEX_op_br, label_arg(l));
 }
 
diff --git a/tcg/tcg.c b/tcg/tcg.c
index 963cb37892..99afc65126 100644
--- a/tcg/tcg.c
+++ b/tcg/tcg.c
@@ -2171,6 +2171,26 @@ static void process_op_defs(TCGContext *s)
 
 void tcg_op_remove(TCGContext *s, TCGOp *op)
 {
+    TCGLabel *label;
+
+    switch (op->opc) {
+    case INDEX_op_br:
+        label = arg_label(op->args[0]);
+        label->refs--;
+        break;
+    case INDEX_op_brcond_i32:
+    case INDEX_op_brcond_i64:
+        label = arg_label(op->args[3]);
+        label->refs--;
+        break;
+    case INDEX_op_brcond2_i32:
+        label = arg_label(op->args[5]);
+        label->refs--;
+        break;
+    default:
+        break;
+    }
+
     QTAILQ_REMOVE(&s->ops, op, link);
     QTAILQ_INSERT_TAIL(&s->free_ops, op, link);
     s->nb_ops--;
diff --git a/tcg/tcg.h b/tcg/tcg.h
index 492d8dcf10..db2d91867f 100644
--- a/tcg/tcg.h
+++ b/tcg/tcg.h
@@ -244,7 +244,8 @@ typedef struct TCGRelocation {
 
 typedef struct TCGLabel {
     unsigned has_value : 1;
-    unsigned id : 31;
+    unsigned id : 15;
+    unsigned refs : 16;
     union {
         uintptr_t value;
         tcg_insn_unit *value_ptr;