fix #1246 (#1254)

* fix finding python path which only has python3.

* fix #1246, arm host issue.

* skip assembler tests on non-x86 host.

* update macro of dummy value.

* fix MSVC macro.

* update dummy array value macro.

* restore to original qemu code.

qemu/tcg/i386/tcg-target.c

@@ -77,6 +77,11 @@ static const int tcg_target_call_iarg_regs[] = {
     TCG_REG_R8,
     TCG_REG_R9,
 #else
+#ifdef _MSC_VER
+#ifdef _UC_MSVC_ARRAY_DUMMY
+#error "DUP DEF _UC_MSVC_ARRAY_DUMMY"
+#endif
+#define _UC_MSVC_ARRAY_DUMMY
     /* 32 bit mode uses stack based calling convention (GCC default).
     We add a dummy value here for MSVC compatibility for the error:
     "error C2466: cannot allocate an array of constant size 0"
@@ -85,6 +90,7 @@ static const int tcg_target_call_iarg_regs[] = {
     */
     0,
 #endif
+#endif
 };
 
 static const int tcg_target_call_oarg_regs[] = {

qemu/tcg/optimize.c

@@ -574,9 +574,6 @@ static TCGArg *tcg_constant_folding(TCGContext *s, uint16_t *tcg_opc_ptr,
 
         /* Do copy propagation */
         for (i = nb_oargs; i < nb_oargs + nb_iargs; i++) {
-            if (args[i] >= TCG_MAX_TEMPS) {
-                return NULL;
-            }
             if (temps[args[i]].state == TCG_TEMP_COPY) {
                 args[i] = find_better_copy(s, args[i]);
             }

qemu/tcg/tcg.c

@@ -2378,8 +2378,10 @@ static int tcg_reg_alloc_call(TCGContext *s, const TCGOpDef *def,
     flags = args[nb_oargs + nb_iargs + 1];
 
     nb_regs = ARRAY_SIZE(tcg_target_call_iarg_regs);
-#if TCG_TARGET_REG_BITS == 32
+#ifdef _UC_MSVC_ARRAY_DUMMY
     // do this because msvc cannot have arrays with 0 entries.
+    /* ref: tcg/i386/tcg-target.c: tcg_target_call_iarg_regs,
+        it is added a dummy value, set back to 0. */
     nb_regs = 0;
 #endif
     if (nb_regs > nb_params) {