From ec12091943c49b2f15a0507c6c2007064dca4e0d Mon Sep 17 00:00:00 2001
From: Laurent Vivier <lvivier@redhat.com>
Date: Thu, 3 May 2018 15:08:59 -0400
Subject: [PATCH] tcg: workaround branch instruction overflow in
 tcg_out_qemu_ld/st

ppc64 uses a BC instruction to call the tcg_out_qemu_ld/st
slow path. BC instruction uses a relative address encoded
on 14 bits.

The slow path functions are added at the end of the generated
instructions buffer, in the reverse order of the callers.
So more we have slow path functions more the distance between
the caller (BC) and the function increases.

This patch changes the behavior to generate the functions in
the same order of the callers.

Backports commit 6001f7729e12dd1d810291e4cbf83cee8e07441d from qemu
---
 qemu/tcg/tcg-ldst.inc.c | 8 ++++----
 qemu/tcg/tcg.c          | 2 +-
 qemu/tcg/tcg.h          | 2 +-
 3 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/qemu/tcg/tcg-ldst.inc.c b/qemu/tcg/tcg-ldst.inc.c
index e08f8cbb..85cfab8f 100644
--- a/qemu/tcg/tcg-ldst.inc.c
+++ b/qemu/tcg/tcg-ldst.inc.c
@@ -30,7 +30,7 @@ typedef struct TCGLabelQemuLdst {
     TCGReg datahi_reg;      /* reg index for high word to be loaded or stored */
     tcg_insn_unit *raddr;   /* gen code addr of the next IR of qemu_ld/st IR */
     tcg_insn_unit *label_ptr[2]; /* label pointers to be updated */
-    struct TCGLabelQemuLdst *next;
+    QSIMPLEQ_ENTRY(TCGLabelQemuLdst) next;
 } TCGLabelQemuLdst;
 
 /*
@@ -45,7 +45,7 @@ static bool tcg_out_ldst_finalize(TCGContext *s)
     TCGLabelQemuLdst *lb;
 
     /* qemu_ld/st slow paths */
-    for (lb = s->ldst_labels; lb != NULL; lb = lb->next) {
+    QSIMPLEQ_FOREACH(lb, &s->ldst_labels, next) {
         if (lb->is_ld) {
             tcg_out_qemu_ld_slow_path(s, lb);
         } else {
@@ -71,7 +71,7 @@ static inline TCGLabelQemuLdst *new_ldst_label(TCGContext *s)
 {
     TCGLabelQemuLdst *l = tcg_malloc(s, sizeof(*l));
 
-    l->next = s->ldst_labels;
-    s->ldst_labels = l;
+    QSIMPLEQ_INSERT_TAIL(&s->ldst_labels, l, next);
+
     return l;
 }
diff --git a/qemu/tcg/tcg.c b/qemu/tcg/tcg.c
index 1c432efe..dd8d1ac3 100644
--- a/qemu/tcg/tcg.c
+++ b/qemu/tcg/tcg.c
@@ -2968,7 +2968,7 @@ int tcg_gen_code(TCGContext *s, TranslationBlock *tb)
     s->code_ptr = tb->tc.ptr;
 
 #ifdef TCG_TARGET_NEED_LDST_LABELS
-    s->ldst_labels = NULL;
+    QSIMPLEQ_INIT(&s->ldst_labels);
 #endif
 #ifdef TCG_TARGET_NEED_POOL_LABELS
     s->pool_labels = NULL;
diff --git a/qemu/tcg/tcg.h b/qemu/tcg/tcg.h
index 7444a6dd..2388974d 100644
--- a/qemu/tcg/tcg.h
+++ b/qemu/tcg/tcg.h
@@ -787,7 +787,7 @@ struct TCGContext {
 
     /* These structures are private to tcg-target.inc.c.  */
 #ifdef TCG_TARGET_NEED_LDST_LABELS
-    struct TCGLabelQemuLdst *ldst_labels;
+    QSIMPLEQ_HEAD(ldst_labels, TCGLabelQemuLdst) ldst_labels;
 #endif
 #ifdef TCG_TARGET_NEED_POOL_LABELS
     struct TCGLabelPoolData *pool_labels;