[PATCH] ARM: Make ARMv8-M attribute cmse_nonsecure_call work in Ada

[PATCH] ARM: Make ARMv8-M attribute cmse_nonsecure_call work in Ada

[Eric Botcazou]

[-- Attachment #1: Type: text/plain, Size: 823 bytes --]

Hi,

until most other machine attributes, this one does not work in Ada because,
while it applies to pointer-to-function types, it is explicitly marked as
requiring declarations in the implementation.

Now, in Ada, machine attributes are specified like this:

  type Non_Secure is access procedure;
  pragma Machine_Attribute (Non_Secure, "cmse_nonsecure_call");

i.e. not attached to the declaration of Non_Secure (testcase attached).

So the attached patch extends the support to Ada by also accepting
pointer-to-function types in the handler.

Tested on arm-eabi, OK for the mainline?


2022-10-24  Eric Botcazou  <ebotcazou@adacore.com>

	* config/arm/arm.cc (arm_attribute_table) <cmse_nonsecure_call>: Change
	decl_required field to false.
	(arm_handle_cmse_nonsecure_call): Deal with a TYPE node.


-- 
Eric Botcazou

[-- Attachment #2: p.diff --]
[-- Type: text/x-patch, Size: 2356 bytes --]

diff --git a/gcc/config/arm/arm.cc b/gcc/config/arm/arm.cc
index ee8f1babf8a..fc96ed9cce4 100644
--- a/gcc/config/arm/arm.cc
+++ b/gcc/config/arm/arm.cc
@@ -375,7 +375,7 @@ static const struct attribute_spec arm_attribute_table[] =
   /* ARMv8-M Security Extensions support.  */
   { "cmse_nonsecure_entry", 0, 0, true, false, false, false,
     arm_handle_cmse_nonsecure_entry, NULL },
-  { "cmse_nonsecure_call", 0, 0, true, false, false, true,
+  { "cmse_nonsecure_call", 0, 0, false, false, false, true,
     arm_handle_cmse_nonsecure_call, NULL },
   { "Advanced SIMD type", 1, 1, false, true, false, true, NULL, NULL },
   { NULL, 0, 0, false, false, false, false, NULL, NULL }
@@ -7605,8 +7605,8 @@ arm_handle_cmse_nonsecure_call (tree *node, tree name,
 				 int /* flags */,
 				 bool *no_add_attrs)
 {
-  tree decl = NULL_TREE, fntype = NULL_TREE;
-  tree type;
+  tree decl = NULL_TREE;
+  tree fntype, type;
 
   if (!use_cmse)
     {
@@ -7616,16 +7616,20 @@ arm_handle_cmse_nonsecure_call (tree *node, tree name,
       return NULL_TREE;
     }
 
-  if (TREE_CODE (*node) == VAR_DECL || TREE_CODE (*node) == TYPE_DECL)
+  if (DECL_P (*node))
     {
-      decl = *node;
-      fntype = TREE_TYPE (decl);
+      fntype = TREE_TYPE (*node);
+
+      if (TREE_CODE (*node) == VAR_DECL || TREE_CODE (*node) == TYPE_DECL)
+	decl = *node;
     }
+  else
+    fntype = *node;
 
-  while (fntype != NULL_TREE && TREE_CODE (fntype) == POINTER_TYPE)
+  while (fntype && TREE_CODE (fntype) == POINTER_TYPE)
     fntype = TREE_TYPE (fntype);
 
-  if (!decl || TREE_CODE (fntype) != FUNCTION_TYPE)
+  if ((DECL_P (*node) && !decl) || TREE_CODE (fntype) != FUNCTION_TYPE)
     {
 	warning (OPT_Wattributes, "%qE attribute only applies to base type of a "
 		 "function pointer", name);
@@ -7640,10 +7644,17 @@ arm_handle_cmse_nonsecure_call (tree *node, tree name,
 
   /* Prevent trees being shared among function types with and without
      cmse_nonsecure_call attribute.  */
-  type = TREE_TYPE (decl);
+  if (decl)
+    {
+      type = build_distinct_type_copy (TREE_TYPE (decl));
+      TREE_TYPE (decl) = type;
+    }
+  else
+    {
+      type = build_distinct_type_copy (*node);
+      *node = type;
+    }
 
-  type = build_distinct_type_copy (type);
-  TREE_TYPE (decl) = type;
   fntype = type;
 
   while (TREE_CODE (fntype) != FUNCTION_TYPE)

[-- Attachment #3: p.ads --]
[-- Type: text/x-adasrc, Size: 239 bytes --]

package P is

  type Non_Secure is access procedure;
  pragma Machine_Attribute (Non_Secure, "cmse_nonsecure_call");

  procedure Call (Proc : Non_Secure);

  procedure Foo;
  pragma Machine_Attribute (Foo, "cmse_nonsecure_call");

end P;

[-- Attachment #4: p.adb --]
[-- Type: text/x-adasrc, Size: 122 bytes --]

package body P is

  procedure Call (Proc : Non_Secure) is
  begin
    Proc.all;
  end;

  procedure Foo is null;

end P;

Re: [PATCH] ARM: Make ARMv8-M attribute cmse_nonsecure_call work in Ada

[Ramana Radhakrishnan]

On Mon, Oct 24, 2022 at 9:55 AM Eric Botcazou via Gcc-patches
<gcc-patches@gcc.gnu.org> wrote:
>
> Hi,
>
> until most other machine attributes, this one does not work in Ada because,
> while it applies to pointer-to-function types, it is explicitly marked as
> requiring declarations in the implementation.
>
> Now, in Ada, machine attributes are specified like this:
>
>   type Non_Secure is access procedure;
>   pragma Machine_Attribute (Non_Secure, "cmse_nonsecure_call");
>
> i.e. not attached to the declaration of Non_Secure (testcase attached).
>
> So the attached patch extends the support to Ada by also accepting
> pointer-to-function types in the handler.
>
> Tested on arm-eabi, OK for the mainline?
>


Ok if no regressions, perhaps the test needs to be in the ada test suite ?

regards

Ramana


>
> 2022-10-24  Eric Botcazou  <ebotcazou@adacore.com>
>
>         * config/arm/arm.cc (arm_attribute_table) <cmse_nonsecure_call>: Change
>         decl_required field to false.
>         (arm_handle_cmse_nonsecure_call): Deal with a TYPE node.
>
>
> --
> Eric Botcazou

Re: [PATCH] ARM: Make ARMv8-M attribute cmse_nonsecure_call work in Ada

[Eric Botcazou]

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> Ok if no regressions, perhaps the test needs to be in the ada test suite ?

Thanks.  Sure, testcase added to gnat.dg like so:

	* gnat.dg/machine_attr2.ads, gnat.dg/machine_attr2.adb: New test.

-- 
Eric Botcazou

[-- Attachment #2: machine_attr2.ads --]
[-- Type: text/x-adasrc, Size: 188 bytes --]

package Machine_Attr2 is

  type Non_Secure is access procedure;
  pragma Machine_Attribute (Non_Secure, "cmse_nonsecure_call");

  procedure Call (Proc : Non_Secure);

end Machine_Attr2;

[-- Attachment #3: machine_attr2.adb --]
[-- Type: text/x-adasrc, Size: 354 bytes --]

-- { dg-do compile { target arm*-*-* } }
-- { dg-options "-mcpu=cortex-m33 -mcmse" }

package body Machine_Attr2 is
  
  procedure Call (Proc : Non_Secure) is
  begin
    Proc.all;
  end;

  procedure Foo; -- { dg-warning "only applies to base type" }
  pragma Machine_Attribute (Foo, "cmse_nonsecure_call");
  procedure Foo is null;

end Machine_Attr2;