Merge pull request #48 from rust-lang/feature/alignof

Add ability to get the alignment of a type

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
 ***********************
 

gcc/jit/jit-playback.cc

@@ -1148,6 +1148,17 @@ new_sizeof (type *type)
 
 /* Construct a playback::rvalue instance (wrapping a tree).  */
 
+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)

gcc/jit/jit-playback.h

@@ -173,6 +173,9 @@ class context : public log_user
   rvalue *
   new_sizeof (type *type);
 
+  rvalue *
+  new_alignof (type *type);
+
   rvalue *
   new_string_literal (const char *value);
 

gcc/jit/jit-recording.cc

@@ -1134,7 +1134,7 @@ 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
@@ -1144,7 +1144,22 @@ 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;
 }
@@ -5805,39 +5820,69 @@ 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 ());
 }
 
 /* Implementation of recording::memento::write_reproducer for sizeof
    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));
 }

gcc/jit/jit-recording.h

@@ -52,6 +52,11 @@ class reproducer;
 
 namespace recording {
 
+enum type_info_type {
+    TYPE_INFO_ALIGN_OF,
+    TYPE_INFO_SIZE_OF,
+};
+
 playback::location *
 playback_location (replayer *r, location *loc);
 
@@ -181,6 +186,9 @@ class context : public log_user
   rvalue *
   new_sizeof (type *type);
 
+  rvalue *
+  new_alignof (type *type);
+
   rvalue *
   new_string_literal (const char *value);
 
@@ -1814,14 +1822,16 @@ class memento_of_new_rvalue_from_const : public rvalue
   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;
 
@@ -1837,6 +1847,7 @@ class memento_of_sizeof : public rvalue
 
 private:
   type *m_type;
+  type_info_type m_info_type;
 };
 
 class memento_of_new_string_literal : public rvalue

gcc/jit/libgccjit.cc

@@ -2158,6 +2158,24 @@ gcc_jit_context_new_sizeof (gcc_jit_context *ctxt,
 	  ->new_sizeof (type));
 }
 
+/* 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/libgccjit.h

@@ -1122,6 +1122,19 @@ 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,

gcc/jit/libgccjit.map

@@ -347,3 +347,8 @@ LIBGCCJIT_ABI_37 {
     gcc_jit_function_set_location;
     gcc_jit_rvalue_set_location;
 } LIBGCCJIT_ABI_36;
+
+LIBGCCJIT_ABI_38 {
+  global:
+    gcc_jit_context_new_alignof;
+} LIBGCCJIT_ABI_37;

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.  */
 
@@ -455,6 +462,9 @@ 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},

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);
+}