untyped calls: enable target switching [PR112334]

The computation of apply_args_size and apply_result_size is saved in a
static variable, so that the corresponding _mode arrays are
initialized only once.  That is not compatible with switchable
targets, and ARM's arm_set_current_function, by saving and restoring
target globals, exercises this problem with a testcase such as that in
the PR, in which more than one function in the translation unit calls
__builtin_apply or __builtin_return, respectively.

This patch moves the _size statics into the target_builtins array,
with a bit of ugliness over _plus_one so that zero initialization of
the struct does the right thing.


for  gcc/ChangeLog

	PR target/112334
	* builtins.h (target_builtins): Add fields for apply_args_size
	and apply_result_size.
	* builtins.cc (apply_args_size, apply_result_size): Cache
	results in fields rather than in static variables.
	(get_apply_args_size, set_apply_args_size): New.
	(get_apply_result_size, set_apply_result_size): New.

gcc/builtins.cc

@@ -1403,8 +1403,16 @@ get_memory_rtx (tree exp, tree len)
 
 /* Built-in functions to perform an untyped call and return.  */
 
+#define set_apply_args_size(x) \
+  (this_target_builtins->x_apply_args_size_plus_one = 1 + (x))
+#define get_apply_args_size() \
+  (this_target_builtins->x_apply_args_size_plus_one - 1)
 #define apply_args_mode \
   (this_target_builtins->x_apply_args_mode)
+#define set_apply_result_size(x) \
+  (this_target_builtins->x_apply_result_size_plus_one = 1 + (x))
+#define get_apply_result_size() \
+  (this_target_builtins->x_apply_result_size_plus_one - 1)
 #define apply_result_mode \
   (this_target_builtins->x_apply_result_mode)
 
@@ -1414,7 +1422,7 @@ get_memory_rtx (tree exp, tree len)
 static int
 apply_args_size (void)
 {
-  static int size = -1;
+  int size = get_apply_args_size ();
   int align;
   unsigned int regno;
 
@@ -1447,6 +1455,8 @@ apply_args_size (void)
 	  }
 	else
 	  apply_args_mode[regno] = as_a <fixed_size_mode> (VOIDmode);
+
+      set_apply_args_size (size);
     }
   return size;
 }
@@ -1457,7 +1467,7 @@ apply_args_size (void)
 static int
 apply_result_size (void)
 {
-  static int size = -1;
+  int size = get_apply_result_size ();
   int align, regno;
 
   /* The values computed by this function never change.  */
@@ -1489,6 +1499,8 @@ apply_result_size (void)
 #ifdef APPLY_RESULT_SIZE
       size = APPLY_RESULT_SIZE;
 #endif
+
+      set_apply_result_size (size);
     }
   return size;
 }

gcc/builtins.h

@@ -37,6 +37,13 @@ struct target_builtins {
      register windows, this gives only the outbound registers.
      INCOMING_REGNO gives the corresponding inbound register.  */
   fixed_size_mode_pod x_apply_result_mode[FIRST_PSEUDO_REGISTER];
+
+  /* Nonzero iff the arrays above have been initialized.  The _plus_one suffix
+     is for zero initialization to make it an unreasonable size, used to signal
+     that the size and the corresponding mode array has not been
+     initialized.  */
+  int x_apply_args_size_plus_one;
+  int x_apply_result_size_plus_one;
 };
 
 extern struct target_builtins default_target_builtins;