Add run time support for calling system functions as task.

This patch adds two new opcodes and the infrastructure needed to call
system functions as tasks. The normal %vpi_call will generate an error
if a system function is called as a task. %vpi_call/w will generate a
warning and will ignore any value returned by the function. %vpi_call/i
will ignore the system function return value and will not print a
message. Adding this is a feature request and is supported in
SystemVerilog. Next I need to add flags to control this depending on
the compiler generation and possibly other flags.

I may leave the cast to void (%vpi_call/i) functionality unimplemented
for now.

vvp/README.txt

@@ -799,6 +799,8 @@ Threads call vpi tasks with the %vpi_call or %vpi_func
 instructions. The formats are:
 
    %vpi_call <file-index> <lineno> <name>, <args>... ;
+   %vpi_call/w <file-index> <lineno> <name>, <args>... ;
+   %vpi_call/i <file-index> <lineno> <name>, <args>... ;
    %vpi_func <file-index> <lineno> <name>, <args>... ;
    %vpi_func/r <file-index> <lineno> <name>, <args>... ;
 
@@ -813,6 +815,12 @@ looked up and compared with the registered system tasks/functions.
 The <args>... is a comma (",") separated list of arguments. These are
 made available to the VPI code as vpi handles.
 
+The plain %vpi_call will fail with an error message if a system function
+is called as a task. The /w suffix version will display a warning message
+if a system function is called as a task and will ignore any value that
+the function tries to return. The /i suffix version silently ignores any
+value returned by a system function called as a task.
+
 * The &A<> argument
 
 The &A<> argument is a reference to the word of a variable array. The

vvp/compile.cc

@@ -1679,6 +1679,7 @@ void compile_fork(char*label, struct symb_s dest, struct symb_s scope)
 }
 
 void compile_vpi_call(char*label, char*name,
+                      bool func_as_task_err, bool func_as_task_warn,
                       long file_idx, long lineno,
                       unsigned argc, vpiHandle*argv)
 {
@@ -1691,8 +1692,9 @@ void compile_vpi_call(char*label, char*name,
 
 	/* Create a vpiHandle that bundles the call information, and
 	   store that handle in the instruction. */
-      code->handle = vpip_build_vpi_call(name, 0, 0, 0, argc, argv,
+      code->handle = vpip_build_vpi_call(name, 0, 0, 0,
-                                         file_idx, lineno);
+                                         func_as_task_err, func_as_task_warn,
+                                         argc, argv, file_idx, lineno);
       if (code->handle == 0)
 	    compile_errors += 1;
 
@@ -1714,8 +1716,8 @@ void compile_vpi_func_call(char*label, char*name,
 
 	/* Create a vpiHandle that bundles the call information, and
 	   store that handle in the instruction. */
-      code->handle = vpip_build_vpi_call(name, vbit, vwid, 0, argc, argv,
+      code->handle = vpip_build_vpi_call(name, vbit, vwid, 0, true, false,
-                                         file_idx, lineno);
+                                         argc, argv, file_idx, lineno);
       if (code->handle == 0)
 	    compile_errors += 1;
 

vvp/compile.h

@@ -395,6 +395,7 @@ extern void compile_code(char*label, char*mnem, comp_operands_t opa);
 extern void compile_disable(char*label, struct symb_s symb);
 
 extern void compile_vpi_call(char*label, char*name,
+			     bool func_as_task_err, bool func_as_task_warn,
 			     long file_idx, long lineno,
 			     unsigned argc, vpiHandle*argv);
 

vvp/lexor.lex

@@ -198,6 +198,8 @@ static char* strdupnew(char const *str)
      exceptional parameter requirements) are listed first. */
 
 "%vpi_call" { return K_vpi_call; }
+"%vpi_call/w" { return K_vpi_call_w; }
+"%vpi_call/i" { return K_vpi_call_i; }
 "%vpi_func" { return K_vpi_func; }
 "%vpi_func/r" { return K_vpi_func_r; }
 "%disable"  { return K_disable; }

vvp/parse.y

@@ -84,7 +84,8 @@ static struct __vpiModPath*modpath_dst = 0;
 %token K_RESOLV K_SCOPE K_SFUNC K_SFUNC_E K_SHIFTL K_SHIFTR K_SHIFTRS
 %token K_THREAD K_TIMESCALE K_TRAN K_TRANIF0 K_TRANIF1 K_TRANVP
 %token K_UFUNC K_UFUNC_E K_UDP K_UDP_C K_UDP_S
-%token K_VAR K_VAR_S K_VAR_I K_VAR_R K_vpi_call K_vpi_func K_vpi_func_r
+%token K_VAR K_VAR_S K_VAR_I K_VAR_R K_vpi_call K_vpi_call_w K_vpi_call_i
+%token K_vpi_func K_vpi_func_r
 %token K_disable K_fork
 %token K_ivl_version K_ivl_delay_selection
 %token K_vpi_module K_vpi_time_precision K_file_names
@@ -540,8 +541,22 @@ statement
      statement is a variant of %vpi_call that includes a thread vector
      after the name, and is used for function calls. */
 
+  /* This version does not allow a function to be called as a task. */
 	| label_opt K_vpi_call T_NUMBER T_NUMBER T_STRING argument_opt ';'
-		{ compile_vpi_call($1, $5, $3, $4, $6.argc, $6.argv); }
+		{ compile_vpi_call($1, $5, true, false, $3, $4,
+		                   $6.argc, $6.argv); }
+
+  /* This version allows a function to be called as a task, but prints a
+   * warning message. */
+	| label_opt K_vpi_call_w T_NUMBER T_NUMBER T_STRING argument_opt ';'
+		{ compile_vpi_call($1, $5, false, true, $3, $4,
+		                   $6.argc, $6.argv); }
+
+  /* This version allows a function to be called as a task and does not
+   * print a message. */
+	| label_opt K_vpi_call_i T_NUMBER T_NUMBER T_STRING argument_opt ';'
+		{ compile_vpi_call($1, $5, false, false, $3, $4,
+		                   $6.argc, $6.argv); }
 
 	| label_opt K_vpi_func T_NUMBER T_NUMBER T_STRING ','
 	  T_NUMBER ',' T_NUMBER argument_opt ';'

vvp/sfunc.cc

@@ -158,7 +158,8 @@ void compile_sfunc(char*label, char*name,  char*format_string,
       vvp_net_t*ptr = new vvp_net_t;
 
       vpiHandle sys = vpip_build_vpi_call(name, 0, width_code, ptr,
-					  argc, vpi_argv, file_idx, lineno);
+                                          true, false, argc, vpi_argv,
+                                          file_idx, lineno);
       assert(sys);
 
 	/* Create and connect the functor to the label. */

vvp/stop.cc

@@ -170,6 +170,7 @@ static void cmd_call(unsigned argc, char*argv[])
 	   when we finish. */
       if (errors == 0) {
 	    vpiHandle call_handle = vpip_build_vpi_call(argv[0], 0, 0, 0,
+	                                                true, false,
 	                                                vpi_argc, vpi_argv,
 	                                                1, 0);
 	    if (call_handle == 0)
@@ -532,4 +533,3 @@ void stop_handler(int rc)
 
       vpi_mcd_printf(1,"** Continue **\n");
 }
-

vvp/vpi_priv.h

@@ -541,6 +541,8 @@ extern unsigned vpip_module_path_cnt;
 extern vpiHandle vpip_build_vpi_call(const char*name,
 				     unsigned vbit, int vwid,
 				     class vvp_net_t*fnet,
+				     bool func_as_task_err,
+				     bool func_as_task_warn,
 				     unsigned argc,
 				     vpiHandle*argv,
 				     long file_idx,

vvp/vpi_tasks.cc

@@ -458,6 +458,13 @@ static vpiHandle sysfunc_put_rnet_value(vpiHandle ref, p_vpi_value vp, int)
       return 0;
 }
 
+static vpiHandle sysfunc_put_no_value(vpiHandle ref, p_vpi_value, int)
+{
+      assert(ref->vpi_type->type_code == vpiSysFuncCall);
+
+      return 0;
+}
+
 
 static const struct __vpirt vpip_sysfunc_rt = {
       vpiSysFuncCall,
@@ -499,6 +506,16 @@ static const struct __vpirt vpip_sysfunc_rnet_rt = {
       systask_iter
 };
 
+static const struct __vpirt vpip_sysfunc_no_rt = {
+      vpiSysFuncCall,
+      sysfunc_get,
+      systask_get_str,
+      0,
+      sysfunc_put_no_value,
+      systask_handle,
+      systask_iter
+};
+
   /* **** Manipulate the internal data structures. **** */
 
 static struct __vpiUserSystf**def_table = 0;
@@ -629,7 +646,7 @@ void vpip_make_systf_system_defined(vpiHandle ref)
  * information so that we can print the file name.
  */
 enum vpi_call_error_type {VPI_CALL_NO_DEF, VPI_CALL_TASK_AS_FUNC,
-                          VPI_CALL_FUNC_AS_TASK};
+                          VPI_CALL_FUNC_AS_TASK, VPI_CALL_FUNC_AS_TASK_WARN};
 typedef struct vpi_call_error {
       vpi_call_error_type type;
       char *name;
@@ -662,23 +679,34 @@ void print_vpi_call_errors()
 		  fprintf(stderr, "%s:%d: Error: System task/function %s() is "
 		                  "not defined by any module.\n",
 		                  file_names[vpi_call_error_lst[idx].file_idx],
-		                  vpi_call_error_lst[idx].lineno,
+		                  (int)vpi_call_error_lst[idx].lineno,
 		                  vpi_call_error_lst[idx].name);
 		  break;
 		case VPI_CALL_TASK_AS_FUNC:
 		  fprintf(stderr, "%s:%d: Error: %s() is a system task, it "
 			          "cannot be called as a function.\n",
 		                  file_names[vpi_call_error_lst[idx].file_idx],
-		                  vpi_call_error_lst[idx].lineno,
+		                  (int)vpi_call_error_lst[idx].lineno,
 		                  vpi_call_error_lst[idx].name);
 		  break;
 		case VPI_CALL_FUNC_AS_TASK:
 		  fprintf(stderr, "%s:%d: Error: %s() is a system function, it "
 			          "cannot be called as a task.\n",
 		                  file_names[vpi_call_error_lst[idx].file_idx],
-		                  vpi_call_error_lst[idx].lineno,
+		                  (int)vpi_call_error_lst[idx].lineno,
 		                  vpi_call_error_lst[idx].name);
 		  break;
+		case VPI_CALL_FUNC_AS_TASK_WARN:
+                 fprintf(stderr, "%s:%d: Warning: Calling system function "
+                                 "%s() as a task.\n",
+		                  file_names[vpi_call_error_lst[idx].file_idx],
+		                  (int)vpi_call_error_lst[idx].lineno,
+		                  vpi_call_error_lst[idx].name);
+                 fprintf(stderr, "%s:%d:          The functions return "
+                                 "value will be ignored.\n",
+                                 file_names[vpi_call_error_lst[idx].file_idx],
+                                 (int)vpi_call_error_lst[idx].lineno);
+		  break;
 	    }
 	    free(vpi_call_error_lst[idx].name);
       }
@@ -699,9 +727,12 @@ void print_vpi_call_errors()
  */
 vpiHandle vpip_build_vpi_call(const char*name, unsigned vbit, int vwid,
 			      class vvp_net_t*fnet,
+			      bool func_as_task_err, bool func_as_task_warn,
 			      unsigned argc, vpiHandle*argv,
 			      long file_idx, long lineno)
 {
+      assert(!(func_as_task_err && func_as_task_warn));
+
       struct __vpiUserSystf*defn = vpip_find_systf(name);
       if (defn == 0) {
 	    add_vpi_call_error(VPI_CALL_NO_DEF, name, file_idx, lineno);
@@ -720,14 +751,19 @@ vpiHandle vpip_build_vpi_call(const char*name, unsigned vbit, int vwid,
 
 	  case vpiSysFunc:
 	    if (vwid == 0 && fnet == 0) {
-		  add_vpi_call_error(VPI_CALL_FUNC_AS_TASK, name, file_idx,
+		  if (func_as_task_err) {
-		                     lineno);
+			add_vpi_call_error(VPI_CALL_FUNC_AS_TASK,
+			                   name, file_idx, lineno);
 			return 0;
+		  } else if (func_as_task_warn) {
+			add_vpi_call_error(VPI_CALL_FUNC_AS_TASK_WARN,
+			                   name, file_idx, lineno);
+		  }
 	    }
 	    break;
 
 	  default:
-	    fprintf(stderr, "Unsupported call type %d.\n",
+	    fprintf(stderr, "Unsupported vpi_call type %d.\n",
 	                    (int)defn->info.type);
 	    assert(0);
       }
@@ -752,6 +788,9 @@ vpiHandle vpip_build_vpi_call(const char*name, unsigned vbit, int vwid,
 	    } else if (vwid > 0) {
 		  obj->base.vpi_type = &vpip_sysfunc_rt;
 
+           } else if (vwid == 0 && fnet == 0) {
+                 obj->base.vpi_type = &vpip_sysfunc_no_rt;
+
 	    } else {
 		  assert(0);
 	    }