[PATCH 10/23] i386: do not cast gen_helper_* function pointers

[Paolo Bonzini]

Use a union to store the various possible kinds of function pointers, and
access the correct one based on the flags.

SSEOpHelper_table6 and SSEOpHelper_table7 right now only have one case,
but this would change with AVX's 3- and 4-argument operations.  Use
unions there too, to keep the code more similar for the three tables.

Extracted from a patch by Paul Brook <paul@nowt.org>.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 target/i386/tcg/translate.c | 75 ++++++++++++++++++-------------------
 1 file changed, 37 insertions(+), 38 deletions(-)

diff --git a/target/i386/tcg/translate.c b/target/i386/tcg/translate.c
index aab04839c8..f7e8cab52d 100644
--- a/target/i386/tcg/translate.c
+++ b/target/i386/tcg/translate.c
@@ -2784,6 +2784,8 @@ typedef void (*SSEFunc_l_ep)(TCGv_i64 val, TCGv_ptr env, 
TCGv_ptr reg);
 typedef void (*SSEFunc_0_epi)(TCGv_ptr env, TCGv_ptr reg, TCGv_i32 val);
 typedef void (*SSEFunc_0_epl)(TCGv_ptr env, TCGv_ptr reg, TCGv_i64 val);
 typedef void (*SSEFunc_0_epp)(TCGv_ptr env, TCGv_ptr reg_a, TCGv_ptr reg_b);
+typedef void (*SSEFunc_0_eppp)(TCGv_ptr env, TCGv_ptr reg_a, TCGv_ptr reg_b,
+                               TCGv_ptr reg_c);
 typedef void (*SSEFunc_0_eppi)(TCGv_ptr env, TCGv_ptr reg_a, TCGv_ptr reg_b,
                                TCGv_i32 val);
 typedef void (*SSEFunc_0_ppi)(TCGv_ptr reg_a, TCGv_ptr reg_b, TCGv_i32 val);
@@ -2798,7 +2800,7 @@ typedef void (*SSEFunc_0_eppt)(TCGv_ptr env, TCGv_ptr 
reg_a, TCGv_ptr reg_b,
 #define SSE_OPF_SHUF      (1 << 9) /* pshufx/shufpx */
 
 #define OP(op, flags, a, b, c, d)       \
-    {flags, {a, b, c, d} }
+    {flags, {{.op = a}, {.op = b}, {.op = c}, {.op = d} } }
 
 #define MMX_OP(x) OP(op1, SSE_OPF_MMX, \
         gen_helper_ ## x ## _mmx, gen_helper_ ## x ## _xmm, NULL, NULL)
@@ -2809,9 +2811,15 @@ typedef void (*SSEFunc_0_eppt)(TCGv_ptr env, TCGv_ptr 
reg_a, TCGv_ptr reg_b,
 #define SSE_OP(sname, dname, op, flags) OP(op, flags, \
         gen_helper_##sname##_xmm, gen_helper_##dname##_xmm, NULL, NULL)
 
+typedef union SSEFuncs {
+    SSEFunc_0_epp op1;
+    SSEFunc_0_ppi op1i;
+    SSEFunc_0_eppt op1t;
+} SSEFuncs;
+
 struct SSEOpHelper_table1 {
     int flags;
-    SSEFunc_0_epp op[4];
+    SSEFuncs fn[4];
 };
 
 #define SSE_3DNOW { SSE_OPF_3DNOW }
@@ -2867,8 +2875,7 @@ static const struct SSEOpHelper_table1 sse_op_table1[256] 
= {
     [0x5f] = SSE_FOP(max),
 
     [0xc2] = SSE_FOP(cmpeq), /* sse_op_table4 */
-    [0xc6] = OP(dummy, SSE_OPF_SHUF, (SSEFunc_0_epp)gen_helper_shufps_xmm,
-                (SSEFunc_0_epp)gen_helper_shufpd_xmm, NULL, NULL),
+    [0xc6] = SSE_OP(shufps, shufpd, op1i, SSE_OPF_SHUF),
 
     /* SSSE3, SSE4, MOVBE, CRC32, BMI1, BMI2, ADX.  */
     [0x38] = SSE_SPECIAL,
@@ -2894,10 +2901,8 @@ static const struct SSEOpHelper_table1 
sse_op_table1[256] = {
     [0x6e] = SSE_SPECIAL, /* movd mm, ea */
     [0x6f] = SSE_SPECIAL, /* movq, movdqa, , movqdu */
     [0x70] = OP(op1i, SSE_OPF_SHUF | SSE_OPF_MMX,
-            (SSEFunc_0_epp)gen_helper_pshufw_mmx,
-            (SSEFunc_0_epp)gen_helper_pshufd_xmm,
-            (SSEFunc_0_epp)gen_helper_pshufhw_xmm,
-            (SSEFunc_0_epp)gen_helper_pshuflw_xmm),
+            gen_helper_pshufw_mmx, gen_helper_pshufd_xmm,
+            gen_helper_pshufhw_xmm, gen_helper_pshuflw_xmm),
     [0x71] = SSE_SPECIAL, /* shiftw */
     [0x72] = SSE_SPECIAL, /* shiftd */
     [0x73] = SSE_SPECIAL, /* shiftq */
@@ -2959,8 +2964,7 @@ static const struct SSEOpHelper_table1 sse_op_table1[256] 
= {
     [0xf5] = MMX_OP(pmaddwd),
     [0xf6] = MMX_OP(psadbw),
     [0xf7] = OP(op1t, SSE_OPF_MMX,
-                (SSEFunc_0_epp)gen_helper_maskmov_mmx,
-                (SSEFunc_0_epp)gen_helper_maskmov_xmm, NULL, NULL),
+                gen_helper_maskmov_mmx, gen_helper_maskmov_xmm, NULL, NULL),
     [0xf8] = MMX_OP(psubb),
     [0xf9] = MMX_OP(psubw),
     [0xfa] = MMX_OP(psubl),
@@ -3057,17 +3061,19 @@ static const SSEFunc_0_epp sse_op_table5[256] = {
     [0xb6] = gen_helper_movq, /* pfrcpit2 */
     [0xb7] = gen_helper_pmulhrw_mmx,
     [0xbb] = gen_helper_pswapd,
-    [0xbf] = gen_helper_pavgb_mmx /* pavgusb */
+    [0xbf] = gen_helper_pavgb_mmx,
 };
 
 struct SSEOpHelper_table6 {
-    SSEFunc_0_epp op[2];
+    SSEFuncs fn[2];
     uint32_t ext_mask;
     int flags;
 };
 
 struct SSEOpHelper_table7 {
-    SSEFunc_0_eppi op[2];
+    union {
+        SSEFunc_0_eppi op1;
+    } fn[2];
     uint32_t ext_mask;
     int flags;
 };
@@ -3075,7 +3081,8 @@ struct SSEOpHelper_table7 {
 #define gen_helper_special_xmm NULL
 
 #define OP(name, op, flags, ext, mmx_name) \
-    {{mmx_name, gen_helper_ ## name ## _xmm}, CPUID_EXT_ ## ext, flags}
+    {{{.op = mmx_name}, {.op = gen_helper_ ## name ## _xmm} }, \
+        CPUID_EXT_ ## ext, flags}
 #define BINARY_OP_MMX(name, ext) \
     OP(name, op1, SSE_OPF_MMX, ext, gen_helper_ ## name ## _mmx)
 #define BINARY_OP(name, ext, flags) \
@@ -3185,11 +3192,9 @@ static void gen_sse(CPUX86State *env, DisasContext *s, 
int b,
     int b1, op1_offset, op2_offset, is_xmm, val;
     int modrm, mod, rm, reg;
     int sse_op_flags;
+    SSEFuncs sse_op_fn;
     const struct SSEOpHelper_table6 *op6;
     const struct SSEOpHelper_table7 *op7;
-    SSEFunc_0_epp sse_fn_epp;
-    SSEFunc_0_ppi sse_fn_ppi;
-    SSEFunc_0_eppt sse_fn_eppt;
     MemOp ot;
 
     b &= 0xff;
@@ -3202,9 +3207,9 @@ static void gen_sse(CPUX86State *env, DisasContext *s, 
int b,
     else
         b1 = 0;
     sse_op_flags = sse_op_table1[b].flags;
-    sse_fn_epp = sse_op_table1[b].op[b1];
+    sse_op_fn = sse_op_table1[b].fn[b1];
     if ((sse_op_flags & (SSE_OPF_SPECIAL | SSE_OPF_3DNOW)) == 0
-            && !sse_fn_epp) {
+            && !sse_op_fn.op1) {
         goto unknown_op;
     }
     if ((b <= 0x5f && b >= 0x10) || b == 0xc6 || b == 0xc2) {
@@ -3618,9 +3623,9 @@ static void gen_sse(CPUX86State *env, DisasContext *s, 
int b,
                 op1_offset = offsetof(CPUX86State,mmx_t0);
             }
             assert(b1 < 2);
-            sse_fn_epp = sse_op_table2[((b - 1) & 3) * 8 +
+            SSEFunc_0_epp fn = sse_op_table2[((b - 1) & 3) * 8 +
                                        (((modrm >> 3)) & 7)][b1];
-            if (!sse_fn_epp) {
+            if (!fn) {
                 goto unknown_op;
             }
             if (is_xmm) {
@@ -3632,7 +3637,7 @@ static void gen_sse(CPUX86State *env, DisasContext *s, 
int b,
             }
             tcg_gen_addi_ptr(s->ptr0, cpu_env, op2_offset);
             tcg_gen_addi_ptr(s->ptr1, cpu_env, op1_offset);
-            sse_fn_epp(cpu_env, s->ptr0, s->ptr1);
+            fn(cpu_env, s->ptr0, s->ptr1);
             break;
         case 0x050: /* movmskps */
             rm = (modrm & 7) | REX_B(s);
@@ -3891,10 +3896,10 @@ static void gen_sse(CPUX86State *env, DisasContext *s, 
int b,
                 }
                 tcg_gen_addi_ptr(s->ptr0, cpu_env, op1_offset);
                 tcg_gen_addi_ptr(s->ptr1, cpu_env, op2_offset);
-                if (!op6->op[b1]) {
+                if (!op6->fn[b1].op1) {
                     goto illegal_op;
                 }
-                op6->op[b1](cpu_env, s->ptr0, s->ptr1);
+                op6->fn[b1].op1(cpu_env, s->ptr0, s->ptr1);
             } else {
                 if ((op6->flags & SSE_OPF_MMX) == 0) {
                     goto unknown_op;
@@ -3909,7 +3914,7 @@ static void gen_sse(CPUX86State *env, DisasContext *s, 
int b,
                 }
                 tcg_gen_addi_ptr(s->ptr0, cpu_env, op1_offset);
                 tcg_gen_addi_ptr(s->ptr1, cpu_env, op2_offset);
-                op6->op[0](cpu_env, s->ptr0, s->ptr1);
+                op6->fn[0].op1(cpu_env, s->ptr0, s->ptr1);
             }
 
             if (op6->flags & SSE_OPF_CMP) {
@@ -4450,8 +4455,8 @@ static void gen_sse(CPUX86State *env, DisasContext *s, 
int b,
                 /* We only actually have one MMX instuction (palignr) */
                 assert(b == 0x0f);
 
-                op7->op[0](cpu_env, s->ptr0, s->ptr1,
-                           tcg_const_i32(val));
+                op7->fn[0].op1(cpu_env, s->ptr0, s->ptr1,
+                               tcg_const_i32(val));
                 break;
             }
 
@@ -4477,7 +4482,7 @@ static void gen_sse(CPUX86State *env, DisasContext *s, 
int b,
 
             tcg_gen_addi_ptr(s->ptr0, cpu_env, op1_offset);
             tcg_gen_addi_ptr(s->ptr1, cpu_env, op2_offset);
-            op7->op[b1](cpu_env, s->ptr0, s->ptr1, tcg_const_i32(val));
+            op7->fn[b1].op1(cpu_env, s->ptr0, s->ptr1, tcg_const_i32(val));
             if (op7->flags & SSE_OPF_CMP) {
                 set_cc_op(s, CC_OP_EFLAGS);
             }
@@ -4603,9 +4608,7 @@ static void gen_sse(CPUX86State *env, DisasContext *s, 
int b,
         tcg_gen_addi_ptr(s->ptr1, cpu_env, op2_offset);
         if (sse_op_flags & SSE_OPF_SHUF) {
             val = x86_ldub_code(env, s);
-            /* XXX: introduce a new table? */
-            sse_fn_ppi = (SSEFunc_0_ppi)sse_fn_epp;
-            sse_fn_ppi(s->ptr0, s->ptr1, tcg_const_i32(val));
+            sse_op_fn.op1i(s->ptr0, s->ptr1, tcg_const_i32(val));
         } else if (b == 0xf7) {
             /* maskmov : we must prepare A0 */
             if (mod != 3) {
@@ -4614,17 +4617,13 @@ static void gen_sse(CPUX86State *env, DisasContext *s, 
int b,
             tcg_gen_mov_tl(s->A0, cpu_regs[R_EDI]);
             gen_extu(s->aflag, s->A0);
             gen_add_A0_ds_seg(s);
-
-            /* XXX: introduce a new table? */
-            sse_fn_eppt = (SSEFunc_0_eppt)sse_fn_epp;
-            sse_fn_eppt(cpu_env, s->ptr0, s->ptr1, s->A0);
+            sse_op_fn.op1t(cpu_env, s->ptr0, s->ptr1, s->A0);
         } else if (b == 0xc2) {
             /* compare insns, bits 7:3 (7:5 for AVX) are ignored */
             val = x86_ldub_code(env, s) & 7;
-            sse_fn_epp = sse_op_table4[val][b1];
-            sse_fn_epp(cpu_env, s->ptr0, s->ptr1);
+            sse_op_table4[val][b1](cpu_env, s->ptr0, s->ptr1);
         } else {
-            sse_fn_epp(cpu_env, s->ptr0, s->ptr1);
+            sse_op_fn.op1(cpu_env, s->ptr0, s->ptr1);
         }
 
         if (sse_op_flags & SSE_OPF_CMP) {
-- 
2.37.1