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.

Cc: qemu-stable@nongnu.org
Fixes: 15fa08f845 ("tcg: Dynamically allocate TCGOps")
Signed-off-by: Laurent Vivier <lvivier@redhat.com>
Message-Id: <20180429235840.16659-1-lvivier@redhat.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

diff --git a/tcg/tcg-ldst.inc.c b/tcg/tcg-ldst.inc.c
index 0e14cf43571ec4fa8dbf65139eb24dc8d2580d5b..47f41b921b8436c28175949e000a68dc9e31dc05 100644 (file)
--- a/tcg/tcg-ldst.inc.c
+++ b/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;
 
 
@@ -46,7 +46,7 @@ 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 {
@@ -72,7 +72,7 @@ static inline TCGLabelQemuLdst *new_ldst_label(TCGContext *s)
 {
     TCGLabelQemuLdst *l = tcg_malloc(sizeof(*l));
 
-    l->next = s->ldst_labels;
-    s->ldst_labels = l;
+    QSIMPLEQ_INSERT_TAIL(&s->ldst_labels, l, next);
+
     return l;
 }

diff --git a/tcg/tcg.c b/tcg/tcg.c
index b5e706bc49d55cde1de9e8e002aad6b8e69f746e..551caf1c53a22fe3bb5aeacb7b020fa84eb38a50 100644 (file)
--- a/tcg/tcg.c
+++ b/tcg/tcg.c
@@ -3297,7 +3297,7 @@ 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/tcg/tcg.h b/tcg/tcg.h
index eb0d4f6ca7205c0fb7619ddb5556ca35e4b7e49e..75fbad128b5e4e09a1e21c670e631703bc2d5b41 100644 (file)
--- a/tcg/tcg.h
+++ b/tcg/tcg.h
@@ -699,7 +699,7 @@ 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;