tcg: Add flags argument to bswap opcodes

This will eventually simplify front-end usage, and will allow
backends to unset TCG_TARGET_HAS_MEMORY_BSWAP without loss of
optimization.

The argument is added during expansion, not currently exposed to the
front end translators.  The backends currently only support a flags
value of either TCG_BSWAP_IZ, or (TCG_BSWAP_IZ | TCG_BSWAP_OZ),
since they all require zero top bytes and leave them that way.
At the existing call sites we pass in (TCG_BSWAP_IZ | TCG_BSWAP_OZ),
except for the flags-ignored cases of a 32-bit swap of a 32-bit
value and or a 64-bit swap of a 64-bit value, where we pass 0.

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

1 files changed, 28 insertions, 0 deletions

diff --git a/tcg/tcg.c b/tcg/tcg.c
index 5e53c3348f..5150ed700e 100644
--- a/tcg/tcg.c
+++ b/tcg/tcg.c
@@ -1778,6 +1778,14 @@ static const char * const alignment_name[(MO_AMASK >> MO_ASHIFT) + 1] = {
     [MO_ALIGN_64 >> MO_ASHIFT] = "al64+",
 };
 
+static const char bswap_flag_name[][6] = {
+    [TCG_BSWAP_IZ] = "iz",
+    [TCG_BSWAP_OZ] = "oz",
+    [TCG_BSWAP_OS] = "os",
+    [TCG_BSWAP_IZ | TCG_BSWAP_OZ] = "iz,oz",
+    [TCG_BSWAP_IZ | TCG_BSWAP_OS] = "iz,os",
+};
+
 static inline bool tcg_regset_single(TCGRegSet d)
 {
     return (d & (d - 1)) == 0;
@@ -1921,6 +1929,26 @@ static void tcg_dump_ops(TCGContext *s, bool have_prefs)
                     i = 1;
                 }
                 break;
+            case INDEX_op_bswap16_i32:
+            case INDEX_op_bswap16_i64:
+            case INDEX_op_bswap32_i32:
+            case INDEX_op_bswap32_i64:
+            case INDEX_op_bswap64_i64:
+                {
+                    TCGArg flags = op->args[k];
+                    const char *name = NULL;
+
+                    if (flags < ARRAY_SIZE(bswap_flag_name)) {
+                        name = bswap_flag_name[flags];
+                    }
+                    if (name) {
+                        col += qemu_log(",%s", name);
+                    } else {
+                        col += qemu_log(",$0x%" TCG_PRIlx, flags);
+                    }
+                    i = k = 1;
+                }
+                break;
             default:
                 i = 0;
                 break;