[Guile-commits] 295/437: Always mark return registers as live in epilog

[Andy Wingo]

wingo pushed a commit to branch lightning
in repository guile.

commit 53dd28d682b98da1d687e7d8aafd988c89683a76
Author: pcpa <address@hidden>
Date:   Sun Aug 10 11:39:53 2014 -0300

    Always mark return registers as live in epilog
    
        * lib/lightning.c: Always mark JIT_RET and JIT_FRET as
        live in a function epilog. This is required because
        on some ports a complex sequence, allocating one or more
        registers, may be required to jump from a ret* to the
        epilog, and the lightning api does not have annotations
        to know if a function returns a value, or the type of
        the return value.
---
 ChangeLog       | 10 ++++++++++
 lib/lightning.c | 20 +++++++++++++++++++-
 2 files changed, 29 insertions(+), 1 deletion(-)

diff --git a/ChangeLog b/ChangeLog
index 1097a72..eb9201e 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,15 @@
 2014-08-10 Paulo Andrade <address@hidden>
 
+       * lib/lightning.c: Always mark JIT_RET and JIT_FRET as
+       live in a function epilog. This is required because
+       on some ports a complex sequence, allocating one or more
+       registers, may be required to jump from a ret* to the
+       epilog, and the lightning api does not have annotations
+       to know if a function returns a value, or the type of
+       the return value.
+
+2014-08-10 Paulo Andrade <address@hidden>
+
        * lib/lightning.c: Change the correct live bitmask of
        return registers after a function call in jit_update.
 
diff --git a/lib/lightning.c b/lib/lightning.c
index ecad2be..cb6ddac 100644
--- a/lib/lightning.c
+++ b/lib/lightning.c
@@ -2029,8 +2029,26 @@ _jit_update(jit_state_t *_jit, jit_node_t *node,
                    jit_regset_and(mask, mask, &ztmp);
                }
                break;
-           case jit_code_prolog:       case jit_code_epilog:
+           case jit_code_prolog:
+               jit_regset_set_ui(mask, 0);
+               return;
+           case jit_code_epilog:
                jit_regset_set_ui(mask, 0);
+#if defined(JIT_RET)
+               /* On some backends it may be required to allocate one
+                * or more registers to jump from a jit_ret* to the
+                * epilog label.
+                * Because currently there is no type information,
+                * assume JIT_RET and JIT_FRET are live in the epilog.
+                * Only JIT_RET really should be marked as live, to
+                * prevent it being allocated, usually in the jump to
+                * the epilog, but also mark JIT_FRET as live for the
+                * sake of correctness. */
+               jit_regset_setbit(live, JIT_RET);
+#endif
+#if defined(JIT_FRET)
+               jit_regset_setbit(live, JIT_FRET);
+#endif
                return;
            case jit_code_callr:
                value = jit_regno(node->u.w);