IA-16: add __attribute__ ((cdecl))', __attribute__ ((stdcall))'

As requested (#13) by
Bart Oldeman.

I also added a few test cases --- gcc.traget/ia16/rtd-{2, 3,
4, 5}.c --- to test that these attributes work properly.

gcc/config/ia16/ia16-c.c

@@ -62,6 +62,11 @@ ia16_cpu_cpp_builtins (void)
   def_or_undef_macro ("__IA16_FEATURE_ALLOCABLE_DS_REG",
 		      TARGET_ALLOCABLE_DS_REG);
 
+  /* Define macros for function calling conventions available through
+     __attribute__ ((.)).  */
+  cpp_define (parse_in, "__IA16_FEATURE_ATTRIBUTE_CDECL");
+  cpp_define (parse_in, "__IA16_FEATURE_ATTRIBUTE_STDCALL");
+
   /* Also define a macro to give the function calling convention in use.  */
   def_or_undef_macro ("__IA16_CALLCVT_CDECL", ! TARGET_RTD);
   def_or_undef_macro ("__IA16_CALLCVT_STDCALL", TARGET_RTD);

gcc/config/ia16/ia16.c

@@ -135,16 +135,16 @@ ia16_preferred_reload_class (rtx x ATTRIBUTE_UNUSED, reg_class_t rclass)
 {
   /* Try to avoid roping in %ds.  */
   switch (rclass)
-  {
-  case SEGMENT_REGS:
-    return ES_REGS;
+    {
+    case SEGMENT_REGS:
+      return ES_REGS;
 
-  case SEG_GENERAL_REGS:
-    return ES_GENERAL_REGS;
+    case SEG_GENERAL_REGS:
+      return ES_GENERAL_REGS;
 
-  default:
-    return rclass;
-  }
+    default:
+      return rclass;
+    }
 }
 
 #undef  TARGET_SECONDARY_RELOAD
@@ -373,15 +373,98 @@ ia16_function_ok_for_sibcall (tree decl, tree exp ATTRIBUTE_UNUSED)
 /* Passing Function Arguments on the Stack */
 #undef	TARGET_RETURN_POPS_ARGS
 #define	TARGET_RETURN_POPS_ARGS ia16_return_pops_args
+
+#define IA16_CALLCVT_CDECL	0x01
+#define IA16_CALLCVT_STDCALL	0x02
+
+static unsigned
+ia16_get_callcvt (const_tree type)
+{
+  tree attrs = TYPE_ATTRIBUTES (type);
+
+  if (attrs != NULL_TREE)
+    {
+      if (lookup_attribute ("cdecl", attrs))
+	return IA16_CALLCVT_CDECL;
+
+      if (lookup_attribute ("stdcall", attrs))
+	return IA16_CALLCVT_STDCALL;
+    }
+
+  return TARGET_RTD ? IA16_CALLCVT_STDCALL : IA16_CALLCVT_CDECL;
+}
+
 static int
-ia16_return_pops_args (tree fundecl ATTRIBUTE_UNUSED,
-		       tree funtype ATTRIBUTE_UNUSED, int size)
+ia16_return_pops_args (tree fundecl ATTRIBUTE_UNUSED, tree funtype, int size)
 {
   /* Note that the `-mrtd' calling convention will also be applied to libgcc
      library functions (e.g. __udivdi3).  This usually means that, if we
      compile code using `-mrtd', we will need a libgcc multilib compiled with
      `-mrtd' to link against our code.  */
-  return TARGET_RTD && ! stdarg_p (funtype) ? size : 0;
+  if (ia16_get_callcvt (funtype) == IA16_CALLCVT_STDCALL
+      && ! stdarg_p (funtype))
+    return size;
+
+  return 0;
+}
+
+/* Defining target-specific uses of __attribute__ */
+#undef	TARGET_ATTRIBUTE_TABLE
+#define	TARGET_ATTRIBUTE_TABLE ia16_attribute_table
+
+static tree
+ia16_handle_cconv_attribute (tree *node, tree name, tree args ATTRIBUTE_UNUSED,
+			     int flags ATTRIBUTE_UNUSED, bool *no_add_attrs)
+{
+  switch (TREE_CODE (*node))
+    {
+    case FUNCTION_TYPE:
+    case METHOD_TYPE:
+    case FIELD_DECL:
+    case TYPE_DECL:
+      break;
+
+    default:
+      warning (OPT_Wattributes, "%qE attribute only applies to functions",
+				name);
+      *no_add_attrs = true;
+      return NULL_TREE;
+    }
+
+  if (is_attribute_p ("stdcall", name)
+       && lookup_attribute ("cdecl", TYPE_ATTRIBUTES (*node)))
+    {
+      error ("stdcall and cdecl attributes are not compatible");
+      *no_add_attrs = true;
+    }
+  else if (is_attribute_p ("cdecl", name)
+	   && lookup_attribute ("stdcall", TYPE_ATTRIBUTES (*node)))
+    {
+      error ("stdcall and cdecl attributes are not compatible");
+      *no_add_attrs = true;
+    }
+
+  return NULL_TREE;
+}
+
+static const struct attribute_spec ia16_attribute_table[] =
+{
+  { "stdcall", 0, 0, false, true, true, ia16_handle_cconv_attribute, true },
+  { "cdecl",   0, 0, false, true, true, ia16_handle_cconv_attribute, true },
+  { NULL,      0, 0, false, false, false, NULL,			     false }
+};
+
+#undef	TARGET_COMP_TYPE_ATTRIBUTES
+#define TARGET_COMP_TYPE_ATTRIBUTES ia16_comp_type_attributes
+
+static int
+ia16_comp_type_attributes (const_tree type1, const_tree type2)
+{
+  if (TREE_CODE (type1) != FUNCTION_TYPE
+      || TREE_CODE (type1) != METHOD_TYPE)
+    return 1;
+
+  return ia16_get_callcvt (type1) == ia16_get_callcvt (type2);
 }
 
 /* Addressing Modes */

gcc/config/ia16/ia16.h

@@ -571,7 +571,7 @@ enum reg_class {	/*	 17 16 15 14 13 12 11 10  9  8  7  6  5  4  3  2  1  0 */
  * Mode Switching Instructions
 
  * Defining target-specific uses of __attribute__
- * Maybe __attribute("far")__ some day.
+ * This is done in ia16.c .
 
  * Defining coprocessor specifics for MIPS targets.
 

gcc/testsuite/gcc.target/ia16/rtd-1.c

@@ -16,7 +16,8 @@ inc (unsigned x)
   return x + 1;
 }
 
-int main (int argc, char **argv, ...)
+int
+main (int argc, char **argv, ...)
 {
   unsigned i;
 

gcc/testsuite/gcc.target/ia16/rtd-2.c

@@ -0,0 +1,42 @@
+/* { dg-do run } */
+/* { dg-options "-Os --save-temps" } */
+
+/* Test whether `__attribute__ ((stdcall))' works correctly, and still gets
+   the program linked with the correct (non-stdcall) libgcc multilib.  */
+
+extern void abort (void);
+
+volatile unsigned long long quotient = 0x55bde67343803983ull,
+			    divisor = 0x1670107447a23170ull;
+
+__attribute__ ((stdcall)) unsigned
+inc (unsigned x)
+{
+  return x + 1;
+}
+
+int
+main (int argc, char **argv)
+{
+  unsigned i;
+
+  /* If this code is linked against the wrong libgcc, this loop will
+     eventually cause a stack overflow and corrupt the data area.  */
+  for (i = 0; i < 10000; ++i)
+    {
+      unsigned long long mod = quotient % divisor;
+      if (mod != 0x126db5166c99a533ull)
+	abort ();
+    }
+
+  return 0;
+}
+
+/* inc (.) should pop one shortword: */
+/* { dg-final { scan-assembler "ret\[ \\t\]\\\$2" } } */
+
+/* main (...) should _not_ pop two shortwords: */
+/* { dg-final { scan-assembler-not "ret\[ \\t\]\\\$4" } } */
+
+/* main (...) should adjust the stack after calling __umoddi3: */
+/* { dg-final { scan-assembler "addw\[ \\t\]\\$.*,\[ \\t\]%sp" } } */

gcc/testsuite/gcc.target/ia16/rtd-3.c

@@ -0,0 +1,40 @@
+/* { dg-do run } */
+/* { dg-options "-mrtd -Os --save-temps" } */
+
+/* Test whether the `-mrtd' switch in conjunction with __attribute__
+   ((cdecl)) works correctly and links with the correct libgcc multilib.  */
+
+extern void abort (void);
+
+volatile unsigned long long quotient = 0x55bde67343803983ull,
+			    divisor = 0x1670107447a23170ull;
+
+unsigned
+inc (unsigned x)
+{
+  return x + 1;
+}
+
+__attribute__ ((cdecl)) int
+main (int argc, char **argv)
+{
+  unsigned i;
+
+  for (i = 0; i < 10000; ++i)
+    {
+      unsigned long long mod = quotient % divisor;
+      if (mod != 0x126db5166c99a533ull)
+	abort ();
+    }
+
+  return 0;
+}
+
+/* inc (.) should pop one shortword: */
+/* { dg-final { scan-assembler "ret\[ \\t\]\\\$2" } } */
+
+/* main (...) should _not_ pop two shortwords: */
+/* { dg-final { scan-assembler-not "ret\[ \\t\]\\\$4" } } */
+
+/* main (...) should not adjust the stack after calling __umoddi3: */
+/* { dg-final { scan-assembler-not "addw\[ \\t\]\\$.*,\[ \\t\]%sp" } } */

gcc/testsuite/gcc.target/ia16/rtd-4.c

@@ -0,0 +1,11 @@
+/* { dg-do assemble } */
+/* { dg-xfail-if "" *-*-* } */
+/* { dg-options "-mrtd -Os --save-temps" } */
+
+/* XFAIL: the `cdecl' and `stdcall' attributes do not mix.  */
+
+__attribute__ ((cdecl, stdcall)) unsigned
+inc (unsigned x)
+{
+  return x + 1;
+}

gcc/testsuite/gcc.target/ia16/rtd-5.c

@@ -0,0 +1,11 @@
+/* { dg-do assemble } */
+/* { dg-xfail-if "" *-*-* } */
+/* { dg-options "-mrtd -Os --save-temps" } */
+
+/* XFAIL: the `cdecl' and `stdcall' attributes do not mix.  */
+
+__attribute__ ((stdcall, cdecl)) unsigned
+inc (unsigned x)
+{
+  return x + 1;
+}