libgccjit: Add support for bitcasts [PR104071]

gcc/jit/
	PR jit/104071
	* docs/_build/texinfo/libgccjit.texi: Regenerate.
	* docs/topics/compatibility.rst (LIBGCCJIT_ABI_21): New ABI tag.
	* docs/topics/expressions.rst: Add documentation for the
	function gcc_jit_context_new_bitcast.
	* jit-playback.cc: New function (new_bitcast).
	* jit-playback.h: New function (new_bitcast).
	* jit-recording.cc: New functions (new_bitcast,
	bitcast::replay_into, bitcast::visit_children,
	bitcast::make_debug_string, bitcast::write_reproducer).
	* jit-recording.h: New class (bitcast) and new function
	(new_bitcast, bitcast::replay_into, bitcast::visit_children,
	bitcast::make_debug_string, bitcast::write_reproducer,
	bitcast::get_precedence).
	* libgccjit.cc: New function (gcc_jit_context_new_bitcast)
	* libgccjit.h: New function (gcc_jit_context_new_bitcast)
	* libgccjit.map (LIBGCCJIT_ABI_21): New ABI tag.

gcc/testsuite/
	PR jit/104071
	* jit.dg/all-non-failing-tests.h: Add new test-bitcast.
	* jit.dg/test-bitcast.c: New test.
	* jit.dg/test-error-bad-bitcast.c: New test.
	* jit.dg/test-error-bad-bitcast2.c: New test.

gcc/
	PR jit/104071
	* toplev.cc: Call the new function tree_cc_finalize in
	toplev::finalize.
	* tree.cc: New functions (clear_nonstandard_integer_type_cache
	and tree_cc_finalize) to clear the cache of non-standard integer
	types to avoid having issues with some optimizations of
	bitcast where the SSA_NAME will have a size of a cached
	integer type that should have been invalidated, causing a
	comparison of integer constant to fail.
	* tree.h: New function (tree_cc_finalize).

gcc/jit/docs/topics/compatibility.rst

@@ -334,3 +334,12 @@ of a global with an rvalue and to use constructors:
   * :c:macro:`GCC_JIT_TYPE_INT32_T`
   * :c:macro:`GCC_JIT_TYPE_INT64_T`
   * :c:macro:`GCC_JIT_TYPE_INT128_T`
+
+.. _LIBGCCJIT_ABI_21:
+
+``LIBGCCJIT_ABI_21``
+--------------------
+``LIBGCCJIT_ABI_21`` covers the addition of an API entrypoint to bitcast a
+value from one type to another:
+
+  * :func:`gcc_jit_context_new_bitcast`

gcc/jit/docs/topics/expressions.rst

@@ -653,6 +653,25 @@ Type-coercion
      * int <-> bool
      * P*  <-> Q*, for pointer types P and Q
 
+.. function:: gcc_jit_rvalue *\
+              gcc_jit_context_new_bitcast (gcc_jit_context *ctxt,\
+                                           gcc_jit_location *loc,\
+                                           gcc_jit_rvalue *rvalue,\
+                                           gcc_jit_type *type)
+
+   Given an rvalue of T, bitcast it to another type, meaning that this will
+   generate a new rvalue by interpreting the bits of ``rvalue`` to the layout
+   of ``type``.
+
+   The type of rvalue must be the same size as the size of ``type``.
+
+   This entrypoint was added in :ref:`LIBGCCJIT_ABI_21`; you can test for
+   its presence using
+
+   .. code-block:: c
+
+      #ifdef LIBGCCJIT_HAVE_gcc_jit_context_new_bitcast
+
 Lvalues
 -------
 

gcc/jit/jit-playback.cc

@@ -1422,6 +1422,36 @@ new_cast (playback::location *loc,
   return new rvalue (this, t_cast);
 }
 
+/* Construct a playback::rvalue instance (wrapping a tree) for a
+   bitcast.  */
+
+playback::rvalue *
+playback::context::
+new_bitcast (location *loc,
+	     rvalue *expr,
+	     type *type_)
+{
+  tree expr_size = TYPE_SIZE (expr->get_type ()->as_tree ());
+  tree type_size = TYPE_SIZE (type_->as_tree ());
+  tree t_expr = expr->as_tree ();
+  tree t_dst_type = type_->as_tree ();
+  if (expr_size != type_size)
+  {
+    active_playback_ctxt->add_error (loc,
+      "bitcast with types of different sizes");
+    fprintf (stderr, "input expression (size: %ld):\n",
+      tree_to_uhwi (expr_size));
+    debug_tree (t_expr);
+    fprintf (stderr, "requested type (size: %ld):\n",
+      tree_to_uhwi (type_size));
+    debug_tree (t_dst_type);
+  }
+  tree t_bitcast = build1 (VIEW_CONVERT_EXPR, t_dst_type, t_expr);
+  if (loc)
+    set_tree_location (t_bitcast, loc);
+  return new rvalue (this, t_bitcast);
+}
+
 /* Construct a playback::lvalue instance (wrapping a tree) for an
    array access.  */
 

gcc/jit/jit-playback.h

@@ -180,6 +180,11 @@ public:
 	    rvalue *expr,
 	    type *type_);
 
+  rvalue *
+  new_bitcast (location *loc,
+	       rvalue *expr,
+	       type *type_);
+
   lvalue *
   new_array_access (location *loc,
 		    rvalue *ptr,

gcc/jit/jit-recording.cc

@@ -1246,6 +1246,22 @@ recording::context::new_cast (recording::location *loc,
   return result;
 }
 
+/* Create a recording::bitcast instance and add it to this context's list
+   of mementos.
+
+   Implements the post-error-checking part of
+   gcc_jit_context_new_bitcast.  */
+
+recording::rvalue *
+recording::context::new_bitcast (location *loc,
+				 rvalue *expr,
+				 type *type_)
+{
+  recording::rvalue *result = new bitcast (this, loc, expr, type_);
+  record (result);
+  return result;
+}
+
 /* Create a recording::call instance and add it to this context's list
    of mementos.
 
@@ -5882,6 +5898,56 @@ recording::cast::write_reproducer (reproducer &r)
 	   r.get_identifier_as_type (get_type ()));
 }
 
+/* Implementation of pure virtual hook recording::memento::replay_into
+   for recording::bitcast.  */
+
+void
+recording::bitcast::replay_into (replayer *r)
+{
+  set_playback_obj (r->new_bitcast (playback_location (r, m_loc),
+				    m_rvalue->playback_rvalue (),
+				    get_type ()->playback_type ()));
+}
+
+/* Implementation of pure virtual hook recording::rvalue::visit_children
+   for recording::bitcast.  */
+void
+recording::bitcast::visit_children (rvalue_visitor *v)
+{
+  v->visit (m_rvalue);
+}
+
+/* Implementation of recording::memento::make_debug_string for
+   casts.  */
+
+recording::string *
+recording::bitcast::make_debug_string ()
+{
+  enum precedence prec = get_precedence ();
+  return string::from_printf (m_ctxt,
+			      "bitcast(%s, %s)",
+			      m_rvalue->get_debug_string_parens (prec),
+			      get_type ()->get_debug_string ());
+}
+
+/* Implementation of recording::memento::write_reproducer for casts.  */
+
+void
+recording::bitcast::write_reproducer (reproducer &r)
+{
+  const char *id = r.make_identifier (this, "rvalue");
+  r.write ("  gcc_jit_rvalue *%s =\n"
+	   "    gcc_jit_context_new_bitcast (%s,\n"
+	   "                                 %s, /* gcc_jit_location *loc */\n"
+	   "                                 %s, /* gcc_jit_rvalue *rvalue */\n"
+	   "                                 %s); /* gcc_jit_type *type */\n",
+	   id,
+	   r.get_identifier (get_context ()),
+	   r.get_identifier (m_loc),
+	   r.get_identifier_as_rvalue (m_rvalue),
+	   r.get_identifier_as_type (get_type ()));
+}
+
 /* The implementation of class gcc::jit::recording::base_call.  */
 
 /* The constructor for gcc::jit::recording::base_call.  */

gcc/jit/jit-recording.h

@@ -205,6 +205,11 @@ public:
 	    rvalue *expr,
 	    type *type_);
 
+  rvalue *
+  new_bitcast (location *loc,
+	       rvalue *expr,
+	       type *type_);
+
   lvalue *
   new_array_access (location *loc,
 		    rvalue *ptr,
@@ -1709,6 +1714,33 @@ private:
   rvalue *m_rvalue;
 };
 
+class bitcast : public rvalue
+{
+public:
+  bitcast (context *ctxt,
+	   location *loc,
+	   rvalue *a,
+	   type *type_)
+  : rvalue (ctxt, loc, type_),
+    m_rvalue (a)
+  {}
+
+  void replay_into (replayer *r) FINAL OVERRIDE;
+
+  void visit_children (rvalue_visitor *v) FINAL OVERRIDE;
+
+private:
+  string * make_debug_string () FINAL OVERRIDE;
+  void write_reproducer (reproducer &r) FINAL OVERRIDE;
+  enum precedence get_precedence () const FINAL OVERRIDE
+  {
+    return PRECEDENCE_CAST;
+  }
+
+private:
+  rvalue *m_rvalue;
+};
+
 class base_call : public rvalue
 {
  public:

gcc/jit/libgccjit.cc

@@ -2433,6 +2433,28 @@ gcc_jit_context_new_cast (gcc_jit_context *ctxt,
   return static_cast <gcc_jit_rvalue *> (ctxt->new_cast (loc, rvalue, type));
 }
 
+/* Public entrypoint.  See description in libgccjit.h.
+
+   After error-checking, the real work is done by the
+   gcc::jit::recording::context::new_bitcast method in jit-recording.c.  */
+
+gcc_jit_rvalue *
+gcc_jit_context_new_bitcast (gcc_jit_context *ctxt,
+			     gcc_jit_location *loc,
+			     gcc_jit_rvalue *rvalue,
+			     gcc_jit_type *type)
+{
+  RETURN_NULL_IF_FAIL (ctxt, NULL, loc, "NULL context");
+  JIT_LOG_FUNC (ctxt->get_logger ());
+  /* LOC can be NULL.  */
+  RETURN_NULL_IF_FAIL (rvalue, ctxt, loc, "NULL rvalue");
+  RETURN_NULL_IF_FAIL (type, ctxt, loc, "NULL type");
+  /* We cannot check if the size of rvalue matches the size of type here, so
+   we'll do it at playback. */
+
+  return static_cast <gcc_jit_rvalue *> (ctxt->new_bitcast (loc, rvalue, type));
+}
+
 /* Public entrypoint.  See description in libgccjit.h.
 
    After error-checking, the real work is done by the

gcc/jit/libgccjit.h

@@ -1234,6 +1234,21 @@ gcc_jit_context_new_cast (gcc_jit_context *ctxt,
 			  gcc_jit_rvalue *rvalue,
 			  gcc_jit_type *type);
 
+/* Reinterpret a value as another type.
+
+#define LIBGCCJIT_HAVE_gcc_jit_context_new_bitcast
+
+   The types must be of the same size.
+
+   This API entrypoint was added in LIBGCCJIT_ABI_21; you can test for its
+   presence using
+     #ifdef LIBGCCJIT_HAVE_gcc_jit_context_new_bitcast  */
+extern gcc_jit_rvalue *
+gcc_jit_context_new_bitcast (gcc_jit_context *ctxt,
+			     gcc_jit_location *loc,
+			     gcc_jit_rvalue *rvalue,
+			     gcc_jit_type *type);
+
 extern gcc_jit_lvalue *
 gcc_jit_context_new_array_access (gcc_jit_context *ctxt,
 				  gcc_jit_location *loc,

gcc/jit/libgccjit.map

@@ -238,6 +238,7 @@ LIBGCCJIT_ABI_18 {
 } LIBGCCJIT_ABI_17;
 
 LIBGCCJIT_ABI_19 {
+  global:
     gcc_jit_context_new_array_constructor;
     gcc_jit_context_new_struct_constructor;
     gcc_jit_context_new_union_constructor;
@@ -249,3 +250,8 @@ LIBGCCJIT_ABI_20 {
     gcc_jit_compatible_types;
     gcc_jit_type_get_size;
 } LIBGCCJIT_ABI_19;
+
+LIBGCCJIT_ABI_21 {
+  global:
+    gcc_jit_context_new_bitcast;
+} LIBGCCJIT_ABI_20;

gcc/testsuite/jit.dg/all-non-failing-tests.h

@@ -77,6 +77,13 @@
 /* test-builtin-unreachable.c: We don't add this one, since it touches
    the optimization level of the context as a whole.  */
 
+/* test-bitcast.c */
+#define create_code create_code_bitcast
+#define verify_code verify_code_bitcast
+#include "test-bitcast.c"
+#undef create_code
+#undef verify_code
+
 /* test-calling-external-function.c */
 #define create_code create_code_calling_external_function
 #define verify_code verify_code_calling_external_function
@@ -400,6 +407,9 @@ const struct testcase testcases[] = {
   {"builtin-memcpy",
    create_code_builtin_memcpy,
    verify_code_builtin_memcpy},
+  {"bitcast",
+   create_code_bitcast,
+   verify_code_bitcast},
   {"calling_external_function",
    create_code_calling_external_function,
    verify_code_calling_external_function},

gcc/testsuite/jit.dg/test-bitcast.c

@@ -0,0 +1,61 @@
+#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:
+int32_t
+my_bitcast (float x)
+{
+   return bitcast(x, int32_t);
+}
+   */
+  gcc_jit_type *int32 =
+    gcc_jit_context_get_int_type (ctxt, 4, 1);
+  gcc_jit_type *float_type =
+    gcc_jit_context_get_type (ctxt, GCC_JIT_TYPE_FLOAT);
+
+  gcc_jit_param *x =
+    gcc_jit_context_new_param (
+      ctxt,
+      NULL,
+      float_type, "x");
+  gcc_jit_param *params[1] = {x};
+  gcc_jit_function *func =
+    gcc_jit_context_new_function (ctxt,
+				  NULL,
+				  GCC_JIT_FUNCTION_EXPORTED,
+				  int32,
+				  "my_bitcast",
+				  1, params, 0);
+
+  gcc_jit_block *initial =
+    gcc_jit_function_new_block (func, "initial");
+
+  gcc_jit_block_end_with_return(initial, NULL,
+    gcc_jit_context_new_bitcast(ctxt,
+        NULL,
+        gcc_jit_param_as_rvalue(x),
+        int32
+    ));
+}
+
+void
+verify_code (gcc_jit_context *ctxt, gcc_jit_result *result)
+{
+  typedef int32_t (*my_bitcast_fn_type) (float);
+  CHECK_NON_NULL (result);
+  my_bitcast_fn_type my_bitcast =
+    (my_bitcast_fn_type)gcc_jit_result_get_code (result, "my_bitcast");
+  CHECK_NON_NULL (my_bitcast);
+  int32_t val = my_bitcast (3.1415927f);
+  note ("my_bitcast returned: 0x%x", val);
+  CHECK_VALUE (val, 0x40490FDB);
+}

gcc/testsuite/jit.dg/test-error-bad-bitcast.c

@@ -0,0 +1,62 @@
+#include <stdlib.h>
+#include <stdio.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
+     test_fn ()
+     {
+       char f[4096];
+       return bitcast(f, int);
+     }
+
+     and verify that the API complains about the bad cast.
+  */
+  gcc_jit_type *int_type =
+    gcc_jit_context_get_type (ctxt, GCC_JIT_TYPE_INT);
+  gcc_jit_type *char_type =
+    gcc_jit_context_get_type (ctxt, GCC_JIT_TYPE_CHAR);
+
+
+  gcc_jit_type *array_type =
+    gcc_jit_context_new_array_type (ctxt, NULL, char_type, 4096);
+
+  gcc_jit_function *test_fn =
+    gcc_jit_context_new_function (ctxt, NULL,
+                                  GCC_JIT_FUNCTION_EXPORTED,
+                                  int_type,
+                                  "test_fn",
+                                  0, NULL,
+                                  0);
+  gcc_jit_lvalue *f =
+    gcc_jit_function_new_local (
+      test_fn,
+      NULL,
+      array_type, "f");
+
+  gcc_jit_block *block = gcc_jit_function_new_block (test_fn, NULL);
+
+  gcc_jit_block_end_with_return (
+    block, NULL,
+    gcc_jit_context_new_bitcast (ctxt, NULL,
+			      gcc_jit_lvalue_as_rvalue (f),
+			      int_type));
+}
+
+void
+verify_code (gcc_jit_context *ctxt, gcc_jit_result *result)
+{
+  CHECK_VALUE (result, NULL);
+
+  /* Verify that the correct error message was emitted.  */
+  CHECK_STRING_VALUE (gcc_jit_context_get_first_error (ctxt),
+		      "bitcast with types of different sizes");
+}
+

gcc/testsuite/jit.dg/test-error-bad-bitcast2.c

@@ -0,0 +1,62 @@
+#include <stdlib.h>
+#include <stdio.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:
+
+     char[4096]
+     test_fn ()
+     {
+       int f;
+       return bitcast(f, char[4096]);
+     }
+
+     and verify that the API complains about the bad cast.
+  */
+  gcc_jit_type *int_type =
+    gcc_jit_context_get_type (ctxt, GCC_JIT_TYPE_INT);
+  gcc_jit_type *char_type =
+    gcc_jit_context_get_type (ctxt, GCC_JIT_TYPE_CHAR);
+
+
+  gcc_jit_type *array_type =
+    gcc_jit_context_new_array_type (ctxt, NULL, char_type, 4096);
+
+  gcc_jit_function *test_fn =
+    gcc_jit_context_new_function (ctxt, NULL,
+                                  GCC_JIT_FUNCTION_EXPORTED,
+                                  array_type,
+                                  "test_fn",
+                                  0, NULL,
+                                  0);
+  gcc_jit_lvalue *f =
+    gcc_jit_function_new_local (
+      test_fn,
+      NULL,
+      int_type, "f");
+
+  gcc_jit_block *block = gcc_jit_function_new_block (test_fn, NULL);
+
+  gcc_jit_block_end_with_return (
+    block, NULL,
+    gcc_jit_context_new_bitcast (ctxt, NULL,
+			      gcc_jit_lvalue_as_rvalue (f),
+			      array_type));
+}
+
+void
+verify_code (gcc_jit_context *ctxt, gcc_jit_result *result)
+{
+  CHECK_VALUE (result, NULL);
+
+  /* Verify that the correct error message was emitted.  */
+  CHECK_STRING_VALUE (gcc_jit_context_get_first_error (ctxt),
+		      "bitcast with types of different sizes");
+}
+

gcc/toplev.cc

@@ -2378,6 +2378,7 @@ toplev::finalize (void)
   gcse_cc_finalize ();
   ipa_cp_cc_finalize ();
   ira_costs_cc_finalize ();
+  tree_cc_finalize ();
 
   /* save_decoded_options uses opts_obstack, so these must
      be cleaned up together.  */

gcc/tree.cc

@@ -6985,6 +6985,15 @@ build_reference_type (tree to_type)
   (HOST_BITS_PER_WIDE_INT > 64 ? HOST_BITS_PER_WIDE_INT : 64)
 static GTY(()) tree nonstandard_integer_type_cache[2 * MAX_INT_CACHED_PREC + 2];
 
+static void
+clear_nonstandard_integer_type_cache (void)
+{
+  for (size_t i = 0 ; i < 2 * MAX_INT_CACHED_PREC + 2 ; i++)
+  {
+    nonstandard_integer_type_cache[i] = NULL;
+  }
+}
+
 /* Builds a signed or unsigned integer type of precision PRECISION.
    Used for C bitfields whose precision does not match that of
    built-in target types.  */
@@ -14675,6 +14684,12 @@ get_target_clone_attr_len (tree arglist)
   return str_len_sum;
 }
 
+void
+tree_cc_finalize (void)
+{
+  clear_nonstandard_integer_type_cache ();
+}
+
 #if CHECKING_P
 
 namespace selftest {

gcc/tree.h

@@ -5401,6 +5401,7 @@ extern bool real_minus_onep (const_tree);
 extern void init_ttree (void);
 extern void build_common_tree_nodes (bool);
 extern void build_common_builtin_nodes (void);
+extern void tree_cc_finalize (void);
 extern tree build_nonstandard_integer_type (unsigned HOST_WIDE_INT, int);
 extern tree build_nonstandard_boolean_type (unsigned HOST_WIDE_INT);
 extern tree build_range_type (tree, tree, tree);