Add function to set the initial value of a global variable [PR96089]

TODO: fail if global kind is imported
TODO: doc

2021-05-20  Antoni Boucher  <[email protected]>

    gcc/jit/
            PR target/96089
            * docs/topics/compatibility.rst (LIBGCCJIT_ABI_19): New ABI
            tag.
            * docs/topics/expressions.rst: Add documentation for the
            function gcc_jit_global_set_initializer_value.
            * jit-playback.c: New functions (new_global_with_value,
            set_global_initial_value, new_rvalue_from_struct, new_rvalue_from_array).
            * jit-playback.h: New functions (new_global_with_value,
            set_global_initial_value, new_rvalue_from_struct, new_rvalue_from_array).
            * jit-recording.c: Add support for setting a value to a
            global variable and new methods
            (global_initializer::write_reproducer,
            global_initializer::make_debug_string,
            global_initializer::write_to_dump,
            global_initializer::replay_into,
            context::new_global_value_initializer,
            memento_of_new_rvalue_from_struct::write_reproducer,
            memento_of_new_rvalue_from_struct::make_debug_string,
            memento_of_new_rvalue_from_struct::visit_children,
            memento_of_new_rvalue_from_struct::replay_into,
            memento_of_new_rvalue_from_struct::
              memento_of_new_rvalue_from_struct,
            context::new_rvalue_from_struct,
            memento_of_new_rvalue_from_array::write_reproducer,
            memento_of_new_rvalue_from_array::make_debug_string,
            memento_of_new_rvalue_from_array::visit_children,
            memento_of_new_rvalue_from_array::replay_into,
            memento_of_new_rvalue_from_array::
              memento_of_new_rvalue_from_array,
            new_rvalue_from_array).
            * jit-recording.h: New functions (set_initializer_value,
            new_global_value_initializer, new_rvalue_from_struct, new_rvalue_from_array),
            new field m_initializer_value and new classes (global_initializer,
            memento_of_new_rvalue_from_struct, memento_of_new_rvalue_from_array).
            * libgccjit.c: New macro RETURN_IF_FAIL_PRINTF5 and new
            functions (gcc_jit_global_set_initializer_value,
            gcc_jit_context_new_rvalue_from_struct,
            gcc_jit_context_new_rvalue_from_array).
            * libgccjit.h: New functions (gcc_jit_global_set_initializer_value,
            gcc_jit_context_new_rvalue_from_struct,
            gcc_jit_context_new_rvalue_from_array).
            * libgccjit.map (LIBGCCJIT_ABI_19): New ABI tag.

    gcc/testsuite/
            PR target/96089
            * jit.dg/test-global-set-initializer.c: Add test for the new
            function (gcc_jit_global_set_initializer_value).

Author: antoyo

gcc/jit/docs/topics/compatibility.rst

@@ -302,3 +302,12 @@ thread-local storage model of a variable:
 section of a variable:
 
   * :func:`gcc_jit_lvalue_set_link_section`
+
+.. _LIBGCCJIT_ABI_19:
+
+``LIBGCCJIT_ABI_19``
+-----------------------
+``LIBGCCJIT_ABI_19`` covers the addition of an API entrypoint to set the value
+of a global variable:
+
+  * :func:`gcc_jit_global_set_initializer_value`

gcc/jit/docs/topics/expressions.rst

@@ -643,6 +643,20 @@ Global variables
 
       #ifdef LIBGCCJIT_HAVE_gcc_jit_global_set_initializer
 
+.. function:: void
+              gcc_jit_global_set_initializer_value (gcc_jit_lvalue *global,\
+                                                    gcc_jit_rvalue *value)
+
+   Set an initializer for ``global`` using the specified value.
+   ``global`` must be the same type as ``value``.
+
+   This entrypoint was added in :ref:`LIBGCCJIT_ABI_19`; you can test for
+   its presence using
+
+   .. code-block:: c
+
+      #ifdef LIBGCCJIT_HAVE_gcc_jit_global_set_initializer_value
+
 Working with pointers, structs and unions
 -----------------------------------------
 

gcc/jit/jit-common.h

@@ -117,6 +117,7 @@ namespace recording {
       class compound_type;
         class struct_;
 	class union_;
+      class array_type;
       class vector_type;
     class field;
       class bitfield;

gcc/jit/jit-playback.c

@@ -702,6 +702,39 @@ new_global_initialized (location *loc,
   return global_finalize_lvalue (inner);
 }
 
+playback::lvalue *
+playback::context::
+new_global_with_value (location *loc,
+		       enum gcc_jit_global_kind kind,
+		       type *type,
+		       playback::rvalue *value,
+		       const char *name)
+{
+  tree inner = global_new_decl (loc, kind, type, name);
+
+  tree inner_type = type->as_tree ();
+  tree initial = value->as_tree ();
+  gcc_assert (TREE_CONSTANT (initial));
+  DECL_INITIAL (inner) = initial;
+
+  return global_finalize_lvalue (inner);
+}
+
+void
+playback::context::
+set_global_initial_value (playback::lvalue *global,
+        playback::rvalue *value)
+{
+  tree initial = value->as_tree ();
+  if (!TREE_CONSTANT(initial))
+  {
+    add_error (NULL, "initial value for global is not a constant");
+    debug_tree (initial);
+    gcc_assert(TREE_CONSTANT(initial));
+  }
+  DECL_INITIAL (global->as_tree ()) = initial;
+}
+
 /* Implementation of the various
       gcc::jit::playback::context::new_rvalue_from_const <HOST_TYPE>
    methods.
@@ -852,6 +885,46 @@ playback::context::new_rvalue_from_vector (location *,
   return new rvalue (this, t_ctor);
 }
 
+/* Construct a playback::rvalue instance (wrapping a tree) for a
+   struct.  */
+
+playback::rvalue *
+playback::context::new_rvalue_from_struct (location *,
+					   type *type,
+					   const auto_vec<rvalue *> &fields)
+{
+  vec<constructor_elt, va_gc> *v;
+  vec_alloc (v, fields.length ());
+  tree field_decl = TYPE_FIELDS (type->as_tree ());
+  for (unsigned i = 0; i < fields.length (); ++i)
+  {
+    CONSTRUCTOR_APPEND_ELT (v, field_decl, fields[i]->as_tree ());
+    field_decl = TREE_CHAIN (field_decl);
+  }
+
+  tree t_ctor = build_constructor (type->as_tree (), v);
+  return new rvalue (this, t_ctor);
+}
+
+/* Construct a playback::rvalue instance (wrapping a tree) for a
+   array.  */
+
+playback::rvalue *
+playback::context::new_rvalue_from_array (location *,
+					  type *type,
+					  const auto_vec<rvalue *> &elements)
+{
+  vec<constructor_elt, va_gc> *v;
+  vec_alloc (v, elements.length ());
+  for (unsigned i = 0; i < elements.length (); ++i)
+  {
+    tree index = build_int_cst (long_unsigned_type_node, i);
+    CONSTRUCTOR_APPEND_ELT (v, index, elements[i]->as_tree ());
+  }
+  tree t_ctor = build_constructor (type->as_tree (), v);
+  return new rvalue (this, t_ctor);
+}
+
 /* Coerce a tree expression into a boolean tree expression.  */
 
 tree

gcc/jit/jit-playback.h

@@ -121,6 +121,17 @@ class context : public log_user
                           const void *initializer,
                           const char *name);
 
+  lvalue*
+  new_global_with_value (location *loc,
+			 enum gcc_jit_global_kind kind,
+			 type *type,
+			 rvalue *value,
+			 const char *name);
+
+  void
+  set_global_initial_value (playback::lvalue *global,
+              playback::rvalue *value);
+
   template <typename HOST_TYPE>
   rvalue *
   new_rvalue_from_const (type *type,
@@ -134,6 +145,16 @@ class context : public log_user
 			  type *type,
 			  const auto_vec<rvalue *> &elements);
 
+  rvalue *
+  new_rvalue_from_struct (location *loc,
+			  type *type,
+			  const auto_vec<rvalue *> &fields);
+
+  rvalue *
+  new_rvalue_from_array (location *loc,
+			 type *type,
+			 const auto_vec<rvalue *> &elements);
+
   rvalue *
   new_unary_op (location *loc,
 		enum gcc_jit_unary_op op,