From: Iain Buclaw <ibuclaw@gdcproject.org>
Date: Sat, 18 Apr 2026 18:19:59 +0000 (+0200)
Subject: d: Implement attribute no_split_stack
X-Git-Tag: basepoints/gcc-17~53
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=e6ea8245cde290062359dd933ca63accebce281f;p=thirdparty%2Fgcc.git

d: Implement attribute no_split_stack

Adds handler for @gcc.attributes.attribute("no_split_stack") and the
UDA @gcc.attributes.noSplitStack for compatibility with LDC.

gcc/d/ChangeLog:

	* d-attribs.cc (d_langhook_gnu_attributes): Add no_split_stack
	attribute.
	(d_handle_no_split_stack_attribute): New function.

libphobos/ChangeLog:

	* libdruntime/gcc/attributes.d (noSplitStack): New UDA.

gcc/testsuite/ChangeLog:

	* gdc.dg/attr_no_split_stack.d: New test.
---

diff --git a/gcc/d/d-attribs.cc b/gcc/d/d-attribs.cc
index 1e7493e4d03..3f748b7bef3 100644
--- a/gcc/d/d-attribs.cc
+++ b/gcc/d/d-attribs.cc
@@ -81,6 +81,7 @@ static tree d_handle_restrict_attribute (tree *, tree, tree, int, bool *);
 static tree d_handle_used_attribute (tree *, tree, tree, int, bool *);
 static tree d_handle_visibility_attribute (tree *, tree, tree, int, bool *);
 static tree d_handle_no_sanitize_attribute (tree *, tree, tree, int, bool *);
+static tree d_handle_no_split_stack_attribute (tree *, tree, tree, int, bool *);
 static tree d_handle_simd_attribute (tree *, tree, tree, int, bool *);
 
 /* Helper to define attribute exclusions.  */
@@ -234,6 +235,8 @@ static const attribute_spec d_langhook_gnu_attributes[] =
 	     d_handle_cold_attribute, attr_cold_hot_exclusions),
   ATTR_SPEC ("no_sanitize", 1, -1, true, false, false, false,
 	     d_handle_no_sanitize_attribute, NULL),
+  ATTR_SPEC ("no_split_stack", 0, 0, true, false, false, false,
+	     d_handle_no_split_stack_attribute, NULL),
   ATTR_SPEC ("register", 1, 1, true, false, false, false,
 	     d_handle_register_attribute, NULL),
   ATTR_SPEC ("restrict", 0, 0, true, false, false, false,
@@ -1441,6 +1444,23 @@ d_handle_no_sanitize_attribute (tree *node, tree name, tree args, int,
   return NULL_TREE;
 }
 
+/* Handle a "no_split_stack" attribute; arguments as in
+   struct attribute_spec.handler.  */
+
+static tree
+d_handle_no_split_stack_attribute (tree *node, tree name, tree, int,
+				   bool *no_add_attrs)
+{
+  if (TREE_CODE (*node) != FUNCTION_DECL)
+    {
+      error_at (DECL_SOURCE_LOCATION (*node),
+		"%qE attribute applies only to functions", name);
+      *no_add_attrs = true;
+    }
+
+  return NULL_TREE;
+}
+
 /* Handle a "register" attribute; arguments as in
    struct attribute_spec.handler.  */
 
diff --git a/gcc/testsuite/gdc.dg/attr_no_split_stack.d b/gcc/testsuite/gdc.dg/attr_no_split_stack.d
new file mode 100644
index 00000000000..48f9d8dc402
--- /dev/null
+++ b/gcc/testsuite/gdc.dg/attr_no_split_stack.d
@@ -0,0 +1,21 @@
+// { dg-do compile }
+// { dg-require-effective-target split_stack }
+// { dg-options "-fsplit-stack -fno-moduleinfo" }
+
+import gcc.attributes;
+
+void use(ref int[100]);
+
+void split()
+{
+    int[100] arr;
+    use(arr);
+}
+
+@attribute("no_split_stack")
+void nosplit()
+{
+    int[100] arr;
+    use(arr);
+}
+// { dg-final { scan-assembler-times "__morestack" 1 } }
diff --git a/libphobos/libdruntime/gcc/attributes.d b/libphobos/libdruntime/gcc/attributes.d
index 30fc9feb47d..a69cb904009 100644
--- a/libphobos/libdruntime/gcc/attributes.d
+++ b/libphobos/libdruntime/gcc/attributes.d
@@ -697,6 +697,19 @@ enum naked = attribute("naked");
  */
 alias noSanitize = no_sanitize;
 
+/**
+ * Disables split-stack instrumentation for this function, overriding the
+ * `-fsplit-stack` commandline function.
+ *
+ * Examples:
+ * ---
+ * import gcc.attributes;
+ *
+ * @noSplitStack int user_function() { return 1; }
+ * ---
+ */
+enum noSplitStack = attribute("no_split_stack");
+
 /**
  * Sets the optimization strategy for a function.
  * Valid strategies are "none", "optsize", "minsize". The strategies are