target/m68k: Use DISAS_NORETURN for exceptions

The raise_exception helper does not return.  Do not generate
any code following that.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20180512050250.12774-2-richard.henderson@linaro.org>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>

target/m68k/translate.c

@@ -291,18 +291,18 @@ static void gen_jmp(DisasContext *s, TCGv dest)
     s->is_jmp = DISAS_JUMP;
 }
 
-static void gen_raise_exception(int nr)
+static void gen_exception(DisasContext *s, uint32_t dest, int nr)
 {
-    TCGv_i32 tmp = tcg_const_i32(nr);
+    TCGv_i32 tmp;
 
+    update_cc_op(s);
+    tcg_gen_movi_i32(QREG_PC, dest);
+
+    tmp = tcg_const_i32(nr);
     gen_helper_raise_exception(cpu_env, tmp);
     tcg_temp_free_i32(tmp);
-}
 
-static void gen_exception(DisasContext *s, uint32_t where, int nr)
-{
-    gen_jmp_im(s, where);
-    gen_raise_exception(nr);
+    s->is_jmp = DISAS_NORETURN;
 }
 
 static inline void gen_addr_fault(DisasContext *s)
@@ -6106,7 +6106,6 @@ void gen_intermediate_code(CPUState *cs, TranslationBlock *tb)
 
         if (unlikely(cpu_breakpoint_test(cs, dc->pc, BP_ANY))) {
             gen_exception(dc, dc->pc, EXCP_DEBUG);
-            dc->is_jmp = DISAS_JUMP;
             /* The address covered by the breakpoint must be included in
                [tb->pc, tb->pc + tb->size) in order to for it to be
                properly cleared -- thus we increment the PC here so that
@@ -6150,6 +6149,7 @@ void gen_intermediate_code(CPUState *cs, TranslationBlock *tb)
             tcg_gen_exit_tb(NULL, 0);
             break;
         case DISAS_TB_JUMP:
+        case DISAS_NORETURN:
             /* nothing more to generate */
             break;
         }