tcg/ppc: Enable tcg backend vector compilation

Introduce all of the flags required to enable tcg backend vector support,
and a runtime flag to indicate the host supports Altivec instructions.

For now, do not actually set have_isa_altivec to true, because we have not
yet added all of the code to actually generate all of the required insns.
However, we must define these flags in order to disable ifndefs that create
stub versions of the functions added here.

The change to tcg_out_movi works around a buglet in tcg.c wherein if we
do not define tcg_out_dupi_vec we get a declared but not defined Werror,
but if we only declare it we get a defined but not used Werror.  We need
to this change to tcg_out_movi eventually anyway, so it's no biggie.

Tested-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Reviewed-by: Aleksandar Markovic <amarkovic@wavecomp.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Aleksandar Markovic <amarkovic@wavecomp.com>

tcg/ppc/tcg-target.h

@@ -65,6 +65,7 @@ typedef enum {
 } TCGPowerISA;
 
 extern TCGPowerISA have_isa;
+extern bool have_altivec;
 
 #define have_isa_2_06  (have_isa >= tcg_isa_2_06)
 #define have_isa_3_00  (have_isa >= tcg_isa_3_00)
@@ -143,6 +144,30 @@ extern TCGPowerISA have_isa;
 #define TCG_TARGET_HAS_mulsh_i64        1
 #endif
 
+/*
+ * While technically Altivec could support V64, it has no 64-bit store
+ * instruction and substituting two 32-bit stores makes the generated
+ * code quite large.
+ */
+#define TCG_TARGET_HAS_v64              0
+#define TCG_TARGET_HAS_v128             have_altivec
+#define TCG_TARGET_HAS_v256             0
+
+#define TCG_TARGET_HAS_andc_vec         0
+#define TCG_TARGET_HAS_orc_vec          0
+#define TCG_TARGET_HAS_not_vec          0
+#define TCG_TARGET_HAS_neg_vec          0
+#define TCG_TARGET_HAS_abs_vec          0
+#define TCG_TARGET_HAS_shi_vec          0
+#define TCG_TARGET_HAS_shs_vec          0
+#define TCG_TARGET_HAS_shv_vec          0
+#define TCG_TARGET_HAS_cmp_vec          0
+#define TCG_TARGET_HAS_mul_vec          0
+#define TCG_TARGET_HAS_sat_vec          0
+#define TCG_TARGET_HAS_minmax_vec       0
+#define TCG_TARGET_HAS_bitsel_vec       0
+#define TCG_TARGET_HAS_cmpsel_vec       0
+
 void flush_icache_range(uintptr_t start, uintptr_t stop);
 void tb_target_set_jmp_target(uintptr_t, uintptr_t, uintptr_t);
 

tcg/ppc/tcg-target.inc.c

@@ -66,6 +66,7 @@ static tcg_insn_unit *tb_ret_addr;
 
 TCGPowerISA have_isa;
 static bool have_isel;
+bool have_altivec;
 
 #ifndef CONFIG_SOFTMMU
 #define TCG_GUEST_BASE_REG 30
@@ -714,10 +715,31 @@ static void tcg_out_movi_int(TCGContext *s, TCGType type, TCGReg ret,
     }
 }
 
-static inline void tcg_out_movi(TCGContext *s, TCGType type, TCGReg ret,
-                                tcg_target_long arg)
+static void tcg_out_dupi_vec(TCGContext *s, TCGType type, TCGReg ret,
+                             tcg_target_long val)
 {
-    tcg_out_movi_int(s, type, ret, arg, false);
+    g_assert_not_reached();
+}
+
+static void tcg_out_movi(TCGContext *s, TCGType type, TCGReg ret,
+                         tcg_target_long arg)
+{
+    switch (type) {
+    case TCG_TYPE_I32:
+    case TCG_TYPE_I64:
+        tcg_debug_assert(ret < TCG_REG_V0);
+        tcg_out_movi_int(s, type, ret, arg, false);
+        break;
+
+    case TCG_TYPE_V64:
+    case TCG_TYPE_V128:
+        tcg_debug_assert(ret >= TCG_REG_V0);
+        tcg_out_dupi_vec(s, type, ret, arg);
+        break;
+
+    default:
+        g_assert_not_reached();
+    }
 }
 
 static bool mask_operand(uint32_t c, int *mb, int *me)
@@ -2602,6 +2624,36 @@ static void tcg_out_op(TCGContext *s, TCGOpcode opc, const TCGArg *args,
     }
 }
 
+int tcg_can_emit_vec_op(TCGOpcode opc, TCGType type, unsigned vece)
+{
+    g_assert_not_reached();
+}
+
+static bool tcg_out_dup_vec(TCGContext *s, TCGType type, unsigned vece,
+                            TCGReg dst, TCGReg src)
+{
+    g_assert_not_reached();
+}
+
+static bool tcg_out_dupm_vec(TCGContext *s, TCGType type, unsigned vece,
+                             TCGReg out, TCGReg base, intptr_t offset)
+{
+    g_assert_not_reached();
+}
+
+static void tcg_out_vec_op(TCGContext *s, TCGOpcode opc,
+                           unsigned vecl, unsigned vece,
+                           const TCGArg *args, const int *const_args)
+{
+    g_assert_not_reached();
+}
+
+void tcg_expand_vec_op(TCGOpcode opc, TCGType type, unsigned vece,
+                       TCGArg a0, ...)
+{
+    g_assert_not_reached();
+}
+
 static const TCGTargetOpDef *tcg_target_op_def(TCGOpcode op)
 {
     static const TCGTargetOpDef r = { .args_ct_str = { "r" } };
@@ -2804,6 +2856,10 @@ static void tcg_target_init(TCGContext *s)
 
     tcg_target_available_regs[TCG_TYPE_I32] = 0xffffffff;
     tcg_target_available_regs[TCG_TYPE_I64] = 0xffffffff;
+    if (have_altivec) {
+        tcg_target_available_regs[TCG_TYPE_V64] = 0xffffffff00000000ull;
+        tcg_target_available_regs[TCG_TYPE_V128] = 0xffffffff00000000ull;
+    }
 
     tcg_target_call_clobber_regs = 0;
     tcg_regset_set_reg(tcg_target_call_clobber_regs, TCG_REG_R0);

tcg/ppc/tcg-target.opc.h

@@ -0,0 +1,5 @@
+/*
+ * Target-specific opcodes for host vector expansion.  These will be
+ * emitted by tcg_expand_vec_op.  For those familiar with GCC internals,
+ * consider these to be UNSPEC with names.
+ */