libgccjit: Add ability to get the alignment of a type

gcc/jit/ChangeLog:

	* docs/topics/compatibility.rst (LIBGCCJIT_ABI_28): New ABI tag.
	* docs/topics/expressions.rst: Document gcc_jit_context_new_alignof.
	* jit-playback.cc (new_alignof): New method.
	* jit-playback.h: New method.
	* jit-recording.cc (recording::context::new_alignof): New
	method.
	(recording::memento_of_sizeof::replay_into,
	recording::memento_of_typeinfo::replay_into,
	recording::memento_of_sizeof::make_debug_string,
	recording::memento_of_typeinfo::make_debug_string,
	recording::memento_of_sizeof::write_reproducer,
	recording::memento_of_typeinfo::write_reproducer): Rename.
	* jit-recording.h (enum type_info_type): New enum.
	(class memento_of_sizeof class memento_of_typeinfo): Rename.
	* libgccjit.cc (gcc_jit_context_new_alignof): New function.
	* libgccjit.h (gcc_jit_context_new_alignof): New function.
	* libgccjit.map: New function.

gcc/testsuite/ChangeLog:

	* jit.dg/all-non-failing-tests.h: New test.
	* jit.dg/test-alignof.c: New test.

11 files changed, 221 insertions, 15 deletions

diff --git a/gcc/jit/docs/topics/compatibility.rst b/gcc/jit/docs/topics/compatibility.rst
index 9cfb054..92c3ed2 100644
--- a/gcc/jit/docs/topics/compatibility.rst
+++ b/gcc/jit/docs/topics/compatibility.rst
@@ -397,3 +397,10 @@ on functions and variables:
 --------------------
 ``LIBGCCJIT_ABI_27`` covers the addition of
 :func:`gcc_jit_context_new_sizeof`
+
+.. _LIBGCCJIT_ABI_28:
+
+``LIBGCCJIT_ABI_28``
+--------------------
+``LIBGCCJIT_ABI_28`` covers the addition of
+:func:`gcc_jit_context_new_alignof`
diff --git a/gcc/jit/docs/topics/expressions.rst b/gcc/jit/docs/topics/expressions.rst
index d83d95f..5734f0e 100644
--- a/gcc/jit/docs/topics/expressions.rst
+++ b/gcc/jit/docs/topics/expressions.rst
@@ -140,6 +140,20 @@ Simple expressions
 
      sizeof (type)
 
+.. function:: gcc_jit_rvalue *\
+              gcc_jit_context_new_alignof (gcc_jit_context *ctxt, \
+                                           gcc_jit_type *type)
+
+   Generate an rvalue that is equal to the alignment of ``type``.
+
+   The parameter ``type`` must be non-NULL.
+
+   This is equivalent to this C code:
+
+   .. code-block:: c
+
+     _Alignof (type)
+
 Constructor expressions
 ***********************
 
diff --git a/gcc/jit/jit-playback.cc b/gcc/jit/jit-playback.cc
index 6baa838..b3f54da 100644
--- a/gcc/jit/jit-playback.cc
+++ b/gcc/jit/jit-playback.cc
@@ -1122,6 +1122,17 @@ new_sizeof (type *type)
 
 playback::rvalue *
 playback::context::
+new_alignof (type *type)
+{
+  int alignment = TYPE_ALIGN (type->as_tree ()) / BITS_PER_UNIT;
+  tree inner = build_int_cst (integer_type_node, alignment);
+  return new rvalue (this, inner);
+}
+
+/* Construct a playback::rvalue instance (wrapping a tree).  */
+
+playback::rvalue *
+playback::context::
 new_string_literal (const char *value)
 {
   /* Compare with c-family/c-common.cc: fix_string_type.  */
diff --git a/gcc/jit/jit-playback.h b/gcc/jit/jit-playback.h
index aa6a086..6e97b38 100644
--- a/gcc/jit/jit-playback.h
+++ b/gcc/jit/jit-playback.h
@@ -166,6 +166,9 @@ public:
   new_sizeof (type *type);
 
   rvalue *
+  new_alignof (type *type);
+
+  rvalue *
   new_string_literal (const char *value);
 
   rvalue *
diff --git a/gcc/jit/jit-recording.cc b/gcc/jit/jit-recording.cc
index 5e9ef40..f68d01f 100644
--- a/gcc/jit/jit-recording.cc
+++ b/gcc/jit/jit-recording.cc
@@ -1077,7 +1077,7 @@ recording::context::new_global_init_rvalue (lvalue *variable,
   gbl->set_rvalue_init (init); /* Needed by the global for write dump.  */
 }
 
-/* Create a recording::memento_of_sizeof instance and add it
+/* Create a recording::memento_of_typeinfo instance and add it
    to this context's list of mementos.
 
    Implements the post-error-checking part of
@@ -1087,7 +1087,22 @@ recording::rvalue *
 recording::context::new_sizeof (recording::type *type)
 {
   recording::rvalue *result =
-    new memento_of_sizeof (this, NULL, type);
+    new memento_of_typeinfo (this, NULL, type, TYPE_INFO_SIZE_OF);
+  record (result);
+  return result;
+}
+
+/* Create a recording::memento_of_typeinfo instance and add it
+   to this context's list of mementos.
+
+   Implements the post-error-checking part of
+   gcc_jit_context_new_alignof.  */
+
+recording::rvalue *
+recording::context::new_alignof (recording::type *type)
+{
+  recording::rvalue *result =
+    new memento_of_typeinfo (this, NULL, type, TYPE_INFO_ALIGN_OF);
   record (result);
   return result;
 }
@@ -5476,25 +5491,44 @@ memento_of_new_rvalue_from_const <void *>::write_reproducer (reproducer &r)
 
 } // namespace recording
 
-/* The implementation of class gcc::jit::recording::memento_of_sizeof.  */
+/* The implementation of class gcc::jit::recording::memento_of_typeinfo.  */
 
 /* Implementation of pure virtual hook recording::memento::replay_into
-   for recording::memento_of_sizeof.  */
+   for recording::memento_of_typeinfo.  */
 
 void
-recording::memento_of_sizeof::replay_into (replayer *r)
+recording::memento_of_typeinfo::replay_into (replayer *r)
 {
-  set_playback_obj (r->new_sizeof (m_type->playback_type ()));
+  switch (m_info_type)
+  {
+  case TYPE_INFO_ALIGN_OF:
+    set_playback_obj (r->new_alignof (m_type->playback_type ()));
+    break;
+  case TYPE_INFO_SIZE_OF:
+    set_playback_obj (r->new_sizeof (m_type->playback_type ()));
+    break;
+  }
 }
 
 /* Implementation of recording::memento::make_debug_string for
    sizeof expressions.  */
 
 recording::string *
-recording::memento_of_sizeof::make_debug_string ()
+recording::memento_of_typeinfo::make_debug_string ()
 {
+  const char* ident;
+  switch (m_info_type)
+  {
+    case TYPE_INFO_ALIGN_OF:
+      ident = "_Alignof";
+      break;
+    case TYPE_INFO_SIZE_OF:
+      ident = "sizeof";
+      break;
+  }
   return string::from_printf (m_ctxt,
-			      "sizeof (%s)",
+			      "%s (%s)",
+			      ident,
 			      m_type->get_debug_string ());
 }
 
@@ -5502,13 +5536,24 @@ recording::memento_of_sizeof::make_debug_string ()
    expressions.  */
 
 void
-recording::memento_of_sizeof::write_reproducer (reproducer &r)
+recording::memento_of_typeinfo::write_reproducer (reproducer &r)
 {
+  const char* type;
+  switch (m_info_type)
+  {
+    case TYPE_INFO_ALIGN_OF:
+      type = "align";
+      break;
+    case TYPE_INFO_SIZE_OF:
+      type = "size";
+      break;
+  }
   const char *id = r.make_identifier (this, "rvalue");
   r.write ("  gcc_jit_rvalue *%s =\n"
-    "    gcc_jit_context_new_sizeof (%s, /* gcc_jit_context *ctxt */\n"
-    "                                %s); /* gcc_jit_type *type */\n",
+    "    gcc_jit_context_new_%sof (%s, /* gcc_jit_context *ctxt */\n"
+    "                                (gcc_jit_type *) %s); /* gcc_jit_type *type */\n",
     id,
+    type,
     r.get_identifier (get_context ()),
     r.get_identifier (m_type));
 }
diff --git a/gcc/jit/jit-recording.h b/gcc/jit/jit-recording.h
index d8d16f4..cce25f1 100644
--- a/gcc/jit/jit-recording.h
+++ b/gcc/jit/jit-recording.h
@@ -47,6 +47,11 @@ class reproducer;
 
 namespace recording {
 
+enum type_info_type {
+    TYPE_INFO_ALIGN_OF,
+    TYPE_INFO_SIZE_OF,
+};
+
 playback::location *
 playback_location (replayer *r, location *loc);
 
@@ -173,6 +178,9 @@ public:
   new_sizeof (type *type);
 
   rvalue *
+  new_alignof (type *type);
+
+  rvalue *
   new_string_literal (const char *value);
 
   rvalue *
@@ -1608,14 +1616,16 @@ private:
   HOST_TYPE m_value;
 };
 
-class memento_of_sizeof : public rvalue
+class memento_of_typeinfo : public rvalue
 {
 public:
-  memento_of_sizeof (context *ctxt,
+  memento_of_typeinfo (context *ctxt,
 			 location *loc,
-			 type *type)
+			 type *type,
+			 type_info_type type_info)
   : rvalue (ctxt, loc, ctxt->get_type (GCC_JIT_TYPE_INT)),
-    m_type (type) {}
+    m_type (type),
+    m_info_type (type_info) {}
 
   void replay_into (replayer *r) final override;
 
@@ -1631,6 +1641,7 @@ private:
 
 private:
   type *m_type;
+  type_info_type m_info_type;
 };
 
 class memento_of_new_string_literal : public rvalue
diff --git a/gcc/jit/libgccjit.cc b/gcc/jit/libgccjit.cc
index 445c0d0..eb38da9 100644
--- a/gcc/jit/libgccjit.cc
+++ b/gcc/jit/libgccjit.cc
@@ -2094,6 +2094,24 @@ gcc_jit_context_new_sizeof (gcc_jit_context *ctxt,
 /* Public entrypoint.  See description in libgccjit.h.
 
    After error-checking, the real work is done by the
+   gcc::jit::recording::context::new_alignof method in
+   jit-recording.cc.  */
+
+gcc_jit_rvalue *
+gcc_jit_context_new_alignof (gcc_jit_context *ctxt,
+			     gcc_jit_type *type)
+{
+  RETURN_NULL_IF_FAIL (ctxt, NULL, NULL, "NULL context");
+  RETURN_NULL_IF_FAIL (type, ctxt, NULL, "NULL type");
+  JIT_LOG_FUNC (ctxt->get_logger ());
+
+  return ((gcc_jit_rvalue *)ctxt
+	  ->new_alignof (type));
+}
+
+/* Public entrypoint.  See description in libgccjit.h.
+
+   After error-checking, the real work is done by the
    gcc::jit::recording::context::new_string_literal method in
    jit-recording.cc.  */
 
diff --git a/gcc/jit/libgccjit.h b/gcc/jit/libgccjit.h
index 74e847b..c82a4be 100644
--- a/gcc/jit/libgccjit.h
+++ b/gcc/jit/libgccjit.h
@@ -1105,6 +1105,19 @@ extern gcc_jit_rvalue *
 gcc_jit_context_new_sizeof (gcc_jit_context *ctxt,
 			    gcc_jit_type *type);
 
+#define LIBGCCJIT_HAVE_gcc_jit_context_new_alignof
+
+/* Generates an rvalue that is equal to the alignment of type.
+
+   This API entrypoint was added in LIBGCCJIT_ABI_38; you can test for its
+   presence using
+     #ifdef LIBGCCJIT_HAVE_gcc_jit_context_new_alignof  */
+
+extern gcc_jit_rvalue *
+gcc_jit_context_new_alignof (gcc_jit_context *ctxt,
+			     gcc_jit_type *type);
+
+
 /* String literals. */
 extern gcc_jit_rvalue *
 gcc_jit_context_new_string_literal (gcc_jit_context *ctxt,
diff --git a/gcc/jit/libgccjit.map b/gcc/jit/libgccjit.map
index 99aa597..b02783e 100644
--- a/gcc/jit/libgccjit.map
+++ b/gcc/jit/libgccjit.map
@@ -289,3 +289,8 @@ LIBGCCJIT_ABI_27 {
   global:
     gcc_jit_context_new_sizeof;
 } LIBGCCJIT_ABI_26;
+
+LIBGCCJIT_ABI_28 {
+  global:
+    gcc_jit_context_new_alignof;
+} LIBGCCJIT_ABI_27;
diff --git a/gcc/testsuite/jit.dg/all-non-failing-tests.h b/gcc/testsuite/jit.dg/all-non-failing-tests.h
index 14a0a32..63b4e78 100644
--- a/gcc/testsuite/jit.dg/all-non-failing-tests.h
+++ b/gcc/testsuite/jit.dg/all-non-failing-tests.h
@@ -42,6 +42,13 @@
 #undef create_code
 #undef verify_code
 
+/* test-alignof.c */
+#define create_code create_code_alignof
+#define verify_code verify_code_alignof
+#include "test-alignof.c"
+#undef create_code
+#undef verify_code
+
 /* test-always_inline-attribute.c: This can't be in the testcases array as it needs
    the `-O0` flag.  */
 
@@ -449,6 +456,9 @@ const struct testcase testcases[] = {
   {"accessing_union",
    create_code_accessing_union,
    verify_code_accessing_union},
+  {"alignof",
+   create_code_alignof,
+   verify_code_alignof},
   {"alignment",
    create_code_alignment,
    verify_code_alignment},
diff --git a/gcc/testsuite/jit.dg/test-alignof.c b/gcc/testsuite/jit.dg/test-alignof.c
new file mode 100644
index 0000000..af288a8
--- /dev/null
+++ b/gcc/testsuite/jit.dg/test-alignof.c
@@ -0,0 +1,69 @@
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <stdint.h>
+
+#include "libgccjit.h"
+
+#include "harness.h"
+
+void
+create_code (gcc_jit_context *ctxt, void *user_data)
+{
+  /* Let's try to inject the equivalent of:
+int
+my_alignof ()
+{
+   return _Alignof(int32_t);
+}
+   */
+  gcc_jit_type *int32 =
+    gcc_jit_context_get_int_type (ctxt, 4, 1);
+  gcc_jit_type *int64 =
+    gcc_jit_context_get_int_type (ctxt, 8, 1);
+  gcc_jit_type *int_type =
+    gcc_jit_context_get_type (ctxt, GCC_JIT_TYPE_INT);
+
+  gcc_jit_function *func =
+    gcc_jit_context_new_function (ctxt,
+				  NULL,
+				  GCC_JIT_FUNCTION_EXPORTED,
+				  int_type,
+				  "my_alignof",
+				  0, NULL, 0);
+
+  gcc_jit_block *initial =
+    gcc_jit_function_new_block (func, "initial");
+
+  gcc_jit_field *field1 =
+    gcc_jit_context_new_field (ctxt, NULL, int32, "int32");
+  gcc_jit_field *field2 =
+    gcc_jit_context_new_field (ctxt, NULL, int64, "int64");
+
+  gcc_jit_field *fields[] = {
+    field1,
+    field2,
+  };
+
+  gcc_jit_struct *struct_type =
+    gcc_jit_context_new_struct_type (
+      ctxt,
+      NULL,
+      "ints",
+      2, fields);
+
+  gcc_jit_block_end_with_return(initial, NULL,
+    gcc_jit_context_new_alignof(ctxt, gcc_jit_struct_as_type (struct_type)));
+}
+
+void
+verify_code (gcc_jit_context *ctxt, gcc_jit_result *result)
+{
+  typedef int (*my_alignof_type) ();
+  CHECK_NON_NULL (result);
+  my_alignof_type my_alignof =
+    (my_alignof_type)gcc_jit_result_get_code (result, "my_alignof");
+  CHECK_NON_NULL (my_alignof);
+  int val = my_alignof ();
+  CHECK_VALUE (val, 8);
+}