tcg: Introduce tcg_out_xchg

We will want a backend interface for register swapping.
This is only properly defined for x86; all others get a
stub version that always indicates failure.

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

11 files changed, 55 insertions, 0 deletions

diff --git a/tcg/aarch64/tcg-target.c.inc b/tcg/aarch64/tcg-target.c.inc
index 29bc97ed1c..4ec3cf3172 100644
--- a/tcg/aarch64/tcg-target.c.inc
+++ b/tcg/aarch64/tcg-target.c.inc
@@ -1106,6 +1106,11 @@ static void tcg_out_movi(TCGContext *s, TCGType type, TCGReg rd,
     tcg_out_insn(s, 3305, LDR, 0, rd);
 }
 
+static bool tcg_out_xchg(TCGContext *s, TCGType type, TCGReg r1, TCGReg r2)
+{
+    return false;
+}
+
 static void tcg_out_addi_ptr(TCGContext *s, TCGReg rd, TCGReg rs,
                              tcg_target_long imm)
 {
diff --git a/tcg/arm/tcg-target.c.inc b/tcg/arm/tcg-target.c.inc
index ec65cb5720..8d769ca0a2 100644
--- a/tcg/arm/tcg-target.c.inc
+++ b/tcg/arm/tcg-target.c.inc
@@ -2607,6 +2607,11 @@ static void tcg_out_movi(TCGContext *s, TCGType type,
     tcg_out_movi32(s, COND_AL, ret, arg);
 }
 
+static bool tcg_out_xchg(TCGContext *s, TCGType type, TCGReg r1, TCGReg r2)
+{
+    return false;
+}
+
 static void tcg_out_addi_ptr(TCGContext *s, TCGReg rd, TCGReg rs,
                              tcg_target_long imm)
 {
diff --git a/tcg/i386/tcg-target.c.inc b/tcg/i386/tcg-target.c.inc
index f8c0eed01d..c8e2bf537f 100644
--- a/tcg/i386/tcg-target.c.inc
+++ b/tcg/i386/tcg-target.c.inc
@@ -460,6 +460,7 @@ static bool tcg_target_const_match(int64_t val, TCGType type, int ct)
 #define OPC_VPTERNLOGQ  (0x25 | P_EXT3A | P_DATA16 | P_VEXW | P_EVEX)
 #define OPC_VZEROUPPER  (0x77 | P_EXT)
 #define OPC_XCHG_ax_r32	(0x90)
+#define OPC_XCHG_EvGv   (0x87)
 
 #define OPC_GRP3_Eb     (0xf6)
 #define OPC_GRP3_Ev     (0xf7)
@@ -1078,6 +1079,13 @@ static void tcg_out_movi(TCGContext *s, TCGType type,
     }
 }
 
+static bool tcg_out_xchg(TCGContext *s, TCGType type, TCGReg r1, TCGReg r2)
+{
+    int rexw = type == TCG_TYPE_I32 ? 0 : P_REXW;
+    tcg_out_modrm(s, OPC_XCHG_EvGv + rexw, r1, r2);
+    return true;
+}
+
 static void tcg_out_addi_ptr(TCGContext *s, TCGReg rd, TCGReg rs,
                              tcg_target_long imm)
 {
diff --git a/tcg/loongarch64/tcg-target.c.inc b/tcg/loongarch64/tcg-target.c.inc
index f51c4ce81b..21c2fc9e98 100644
--- a/tcg/loongarch64/tcg-target.c.inc
+++ b/tcg/loongarch64/tcg-target.c.inc
@@ -419,6 +419,11 @@ static void tcg_out_addi(TCGContext *s, TCGType type, TCGReg rd,
     }
 }
 
+static bool tcg_out_xchg(TCGContext *s, TCGType type, TCGReg r1, TCGReg r2)
+{
+    return false;
+}
+
 static void tcg_out_addi_ptr(TCGContext *s, TCGReg rd, TCGReg rs,
                              tcg_target_long imm)
 {
diff --git a/tcg/mips/tcg-target.c.inc b/tcg/mips/tcg-target.c.inc
index b0f9fbc44c..346c614354 100644
--- a/tcg/mips/tcg-target.c.inc
+++ b/tcg/mips/tcg-target.c.inc
@@ -595,6 +595,11 @@ static void tcg_out_extrl_i64_i32(TCGContext *s, TCGReg rd, TCGReg rs)
     tcg_out_ext32s(s, rd, rs);
 }
 
+static bool tcg_out_xchg(TCGContext *s, TCGType type, TCGReg r1, TCGReg r2)
+{
+    return false;
+}
+
 static void tcg_out_addi_ptr(TCGContext *s, TCGReg rd, TCGReg rs,
                              tcg_target_long imm)
 {
diff --git a/tcg/ppc/tcg-target.c.inc b/tcg/ppc/tcg-target.c.inc
index b1d9c0bbe4..77abb7d20c 100644
--- a/tcg/ppc/tcg-target.c.inc
+++ b/tcg/ppc/tcg-target.c.inc
@@ -1154,6 +1154,11 @@ static void tcg_out_movi(TCGContext *s, TCGType type, TCGReg ret,
     }
 }
 
+static bool tcg_out_xchg(TCGContext *s, TCGType type, TCGReg r1, TCGReg r2)
+{
+    return false;
+}
+
 static void tcg_out_addi_ptr(TCGContext *s, TCGReg rd, TCGReg rs,
                              tcg_target_long imm)
 {
diff --git a/tcg/riscv/tcg-target.c.inc b/tcg/riscv/tcg-target.c.inc
index 0d92135bf6..328cbc0ad6 100644
--- a/tcg/riscv/tcg-target.c.inc
+++ b/tcg/riscv/tcg-target.c.inc
@@ -561,6 +561,11 @@ static void tcg_out_movi(TCGContext *s, TCGType type, TCGReg rd,
     tcg_out_opc_imm(s, OPC_LD, rd, rd, 0);
 }
 
+static bool tcg_out_xchg(TCGContext *s, TCGType type, TCGReg r1, TCGReg r2)
+{
+    return false;
+}
+
 static void tcg_out_addi_ptr(TCGContext *s, TCGReg rd, TCGReg rs,
                              tcg_target_long imm)
 {
diff --git a/tcg/s390x/tcg-target.c.inc b/tcg/s390x/tcg-target.c.inc
index 0578fce4d7..b399798664 100644
--- a/tcg/s390x/tcg-target.c.inc
+++ b/tcg/s390x/tcg-target.c.inc
@@ -1076,6 +1076,11 @@ static inline bool tcg_out_sti(TCGContext *s, TCGType type, TCGArg val,
     return false;
 }
 
+static bool tcg_out_xchg(TCGContext *s, TCGType type, TCGReg r1, TCGReg r2)
+{
+    return false;
+}
+
 static void tcg_out_addi_ptr(TCGContext *s, TCGReg rd, TCGReg rs,
                              tcg_target_long imm)
 {
diff --git a/tcg/sparc64/tcg-target.c.inc b/tcg/sparc64/tcg-target.c.inc
index 869d9a0521..4f477d539c 100644
--- a/tcg/sparc64/tcg-target.c.inc
+++ b/tcg/sparc64/tcg-target.c.inc
@@ -542,6 +542,11 @@ static void tcg_out_extrl_i64_i32(TCGContext *s, TCGReg rd, TCGReg rs)
     tcg_out_mov(s, TCG_TYPE_I32, rd, rs);
 }
 
+static bool tcg_out_xchg(TCGContext *s, TCGType type, TCGReg r1, TCGReg r2)
+{
+    return false;
+}
+
 static void tcg_out_addi_ptr(TCGContext *s, TCGReg rd, TCGReg rs,
                              tcg_target_long imm)
 {
diff --git a/tcg/tcg.c b/tcg/tcg.c
index 328e018a80..fde5ccc57c 100644
--- a/tcg/tcg.c
+++ b/tcg/tcg.c
@@ -115,6 +115,8 @@ static void tcg_out_exts_i32_i64(TCGContext *s, TCGReg ret, TCGReg arg);
 static void tcg_out_extu_i32_i64(TCGContext *s, TCGReg ret, TCGReg arg);
 static void tcg_out_extrl_i64_i32(TCGContext *s, TCGReg ret, TCGReg arg);
 static void tcg_out_addi_ptr(TCGContext *s, TCGReg, TCGReg, tcg_target_long);
+static bool tcg_out_xchg(TCGContext *s, TCGType type, TCGReg r1, TCGReg r2)
+    __attribute__((unused));
 static void tcg_out_exit_tb(TCGContext *s, uintptr_t arg);
 static void tcg_out_goto_tb(TCGContext *s, int which);
 static void tcg_out_op(TCGContext *s, TCGOpcode opc,
diff --git a/tcg/tci/tcg-target.c.inc b/tcg/tci/tcg-target.c.inc
index 68531e35ec..4cf03a579c 100644
--- a/tcg/tci/tcg-target.c.inc
+++ b/tcg/tci/tcg-target.c.inc
@@ -645,6 +645,11 @@ static void tcg_out_extrl_i64_i32(TCGContext *s, TCGReg rd, TCGReg rs)
     tcg_out_mov(s, TCG_TYPE_I32, rd, rs);
 }
 
+static bool tcg_out_xchg(TCGContext *s, TCGType type, TCGReg r1, TCGReg r2)
+{
+    return false;
+}
+
 static void tcg_out_addi_ptr(TCGContext *s, TCGReg rd, TCGReg rs,
                              tcg_target_long imm)
 {