libgccjit: Add support for creating temporary variables

gcc/jit/ChangeLog:

	* docs/topics/compatibility.rst (LIBGCCJIT_ABI_26): New ABI tag.
	* docs/topics/functions.rst: Document gcc_jit_function_new_temp.
	* jit-playback.cc (new_local): Add new is_temp parameter.
	* jit-playback.h: Add new is_temp parameter.
	* jit-recording.cc (recording::function::new_temp): New method.
	(recording::local::replay_into): Support temporary variables.
	(recording::local::write_reproducer): Support temporary
	variables.
	* jit-recording.h (new_temp): New method.
	(m_is_temp): New field.
	* libgccjit.cc (gcc_jit_function_new_temp): New function.
	* libgccjit.h (gcc_jit_function_new_temp): New function.
	* libgccjit.map: New function.

gcc/testsuite/ChangeLog:

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

gcc/jit/docs/topics/compatibility.rst

@@ -371,3 +371,12 @@ alignment of a variable:
 
   * :func:`gcc_jit_lvalue_set_alignment`
   * :func:`gcc_jit_lvalue_get_alignment`
+
+.. _LIBGCCJIT_ABI_26:
+
+``LIBGCCJIT_ABI_26``
+--------------------
+``LIBGCCJIT_ABI_26`` covers the addition of a functions to create a new
+temporary variable:
+
+  * :func:`gcc_jit_function_new_temp`

gcc/jit/docs/topics/functions.rst

@@ -171,6 +171,26 @@ Functions
    underlying string, so it is valid to pass in a pointer to an on-stack
    buffer.
 
+.. function:: gcc_jit_lvalue *\
+              gcc_jit_function_new_temp (gcc_jit_function *func,\
+                                         gcc_jit_location *loc,\
+                                         gcc_jit_type *type)
+
+   Create a new local variable within the function, of the given type.
+   This function is similar to :func:`gcc_jit_function_new_local`, but
+   it is to be used for compiler-generated variables (as opposed to
+   user-defined variables in the language to be compiled) and these
+   variables won't show up in the debug info.
+
+   The parameter ``type`` must be non-`void`.
+
+   This entrypoint was added in :ref:`LIBGCCJIT_ABI_26`; you can test
+   for its presence using
+
+   .. code-block:: c
+
+      #ifdef LIBGCCJIT_HAVE_gcc_jit_function_new_temp
+
 .. function::  size_t \
                gcc_jit_function_get_param_count (gcc_jit_function *func)
 

gcc/jit/jit-playback.cc

@@ -31,6 +31,7 @@ along with GCC; see the file COPYING3.  If not see
 #include "toplev.h"
 #include "tree-cfg.h"
 #include "convert.h"
+#include "gimple-expr.h"
 #include "stor-layout.h"
 #include "print-tree.h"
 #include "gimplify.h"
@@ -2153,13 +2154,27 @@ playback::function::
 new_local (location *loc,
 	   type *type,
 	   const char *name,
-	   const std::vector<std::pair<gcc_jit_variable_attribute, std::string>> &attributes)
+	   const std::vector<std::pair<gcc_jit_variable_attribute, std::string>> &attributes,
+	   bool is_temp)
 {
   gcc_assert (type);
-  gcc_assert (name);
-  tree inner = build_decl (UNKNOWN_LOCATION, VAR_DECL,
+  tree inner;
+  if (is_temp)
+  {
+    inner = build_decl (UNKNOWN_LOCATION, VAR_DECL,
+			create_tmp_var_name("JITTMP"),
+			type->as_tree ());
+    DECL_ARTIFICIAL (inner) = 1;
+    DECL_IGNORED_P (inner) = 1;
+    DECL_NAMELESS (inner) = 1;
+  }
+  else
+  {
+    gcc_assert (name);
+    inner = build_decl (UNKNOWN_LOCATION, VAR_DECL,
 			   get_identifier (name),
 			   type->as_tree ());
+  }
   DECL_CONTEXT (inner) = this->m_inner_fndecl;
 
   /* Prepend to BIND_EXPR_VARS: */

gcc/jit/jit-playback.h

@@ -554,7 +554,8 @@ class function : public wrapper
   new_local (location *loc,
 	     type *type,
 	     const char *name,
-	     const std::vector<std::pair<gcc_jit_variable_attribute, std::string>> &attributes);
+	     const std::vector<std::pair<gcc_jit_variable_attribute, std::string>> &attributes,
+	     bool is_temp);
 
   block*
   new_block (const char *name);

gcc/jit/jit-recording.cc

@@ -4447,7 +4447,24 @@ recording::function::new_local (recording::location *loc,
 				type *type,
 				const char *name)
 {
-  local *result = new local (this, loc, type, new_string (name));
+  local *result = new local (this, loc, type, new_string (name), false);
+  m_ctxt->record (result);
+  m_locals.safe_push (result);
+  return result;
+}
+
+/* Create a recording::local instance and add it to
+   the functions's context's list of mementos, and to the function's
+   list of locals.
+
+   Implements the post-error-checking part of
+   gcc_jit_function_new_temp.  */
+
+recording::lvalue *
+recording::function::new_temp (recording::location *loc,
+			       type *type)
+{
+  local *result = new local (this, loc, type, NULL, true);
   m_ctxt->record (result);
   m_locals.safe_push (result);
   return result;
@@ -7213,7 +7230,8 @@ recording::local::replay_into (replayer *r)
       ->new_local (playback_location (r, m_loc),
 		   m_type->playback_type (),
 		   playback_string (m_name),
-		   m_attributes);
+		   m_attributes,
+		   m_is_temp);
 
   if (m_reg_name != NULL)
     obj->set_register_name (m_reg_name->c_str ());
@@ -7244,16 +7262,26 @@ void
 recording::local::write_reproducer (reproducer &r)
 {
   const char *id = r.make_identifier (this, "local");
-  r.write ("  gcc_jit_lvalue *%s =\n"
-	   "    gcc_jit_function_new_local (%s, /* gcc_jit_function *func */\n"
-	   "                                %s, /* gcc_jit_location *loc */\n"
-	   "                                %s, /* gcc_jit_type *type */\n"
-	   "                                %s); /* const char *name */\n",
-	   id,
-	   r.get_identifier (m_func),
-	   r.get_identifier (m_loc),
-	   r.get_identifier_as_type (m_type),
-	   m_name->get_debug_string ());
+  if (m_is_temp)
+    r.write ("  gcc_jit_lvalue *%s =\n"
+	     "    gcc_jit_function_new_temp (%s, /* gcc_jit_function *func */\n"
+	     "                               %s, /* gcc_jit_location *loc */\n"
+	     "                               %s); /* gcc_jit_type *type */\n",
+	     id,
+	     r.get_identifier (m_func),
+	     r.get_identifier (m_loc),
+	     r.get_identifier_as_type (m_type));
+  else
+    r.write ("  gcc_jit_lvalue *%s =\n"
+	     "    gcc_jit_function_new_local (%s, /* gcc_jit_function *func */\n"
+	     "                                %s, /* gcc_jit_location *loc */\n"
+	     "                                %s, /* gcc_jit_type *type */\n"
+	     "                                %s); /* const char *name */\n",
+	     id,
+	     r.get_identifier (m_func),
+	     r.get_identifier (m_loc),
+	     r.get_identifier_as_type (m_type),
+	     m_name->get_debug_string ());
 }
 
 /* The implementation of class gcc::jit::recording::statement.  */

gcc/jit/jit-recording.h

@@ -1515,6 +1515,10 @@ class function : public memento
 	     type *type,
 	     const char *name);
 
+  lvalue *
+  new_temp (location *loc,
+	    type *type);
+
   block*
   new_block (const char *name);
 
@@ -2418,10 +2422,11 @@ class function_pointer : public rvalue
 class local : public lvalue
 {
 public:
-  local (function *func, location *loc, type *type_, string *name)
+  local (function *func, location *loc, type *type_, string *name, bool is_temp)
     : lvalue (func->m_ctxt, loc, type_),
     m_func (func),
-    m_name (name)
+    m_name (name),
+    m_is_temp (is_temp)
   {
     set_scope (func);
   }
@@ -2433,7 +2438,12 @@ class local : public lvalue
   void write_to_dump (dump &d) final override;
 
 private:
-  string * make_debug_string () final override { return m_name; }
+  string * make_debug_string () final override {
+    if (m_is_temp)
+      return m_ctxt->new_string ("temp");
+    else
+      return m_name;
+  }
   void write_reproducer (reproducer &r) final override;
   enum precedence get_precedence () const final override
   {
@@ -2443,6 +2453,7 @@ class local : public lvalue
 private:
   function *m_func;
   string *m_name;
+  bool m_is_temp;
 };
 
 class statement : public memento

gcc/jit/libgccjit.cc

@@ -2928,6 +2928,37 @@ gcc_jit_function_new_local (gcc_jit_function *func,
   return (gcc_jit_lvalue *)func->new_local (loc, type, name);
 }
 
+/* Public entrypoint.  See description in libgccjit.h.
+
+   After error-checking, the real work is done by the
+   gcc::jit::recording::function::new_temp method in jit-recording.cc.  */
+
+gcc_jit_lvalue *
+gcc_jit_function_new_temp (gcc_jit_function *func,
+			   gcc_jit_location *loc,
+			   gcc_jit_type *type)
+{
+  RETURN_NULL_IF_FAIL (func, NULL, loc, "NULL function");
+  gcc::jit::recording::context *ctxt = func->m_ctxt;
+  JIT_LOG_FUNC (ctxt->get_logger ());
+  /* LOC can be NULL.  */
+  RETURN_NULL_IF_FAIL (func->get_kind () != GCC_JIT_FUNCTION_IMPORTED,
+		       ctxt, loc,
+		       "Cannot add temps to an imported function");
+  RETURN_NULL_IF_FAIL (type, ctxt, loc, "NULL type");
+  RETURN_NULL_IF_FAIL_PRINTF1 (
+    type->has_known_size (),
+    ctxt, loc,
+    "unknown size for temp (type: %s)",
+    type->get_debug_string ());
+  RETURN_NULL_IF_FAIL (
+    !type->is_void (),
+    ctxt, loc,
+    "void type for temp");
+
+  return (gcc_jit_lvalue *)func->new_temp (loc, type);
+}
+
 /* Public entrypoint.  See description in libgccjit.h.
 
    After error-checking, the real work is done by the

gcc/jit/libgccjit.h

@@ -1409,6 +1409,13 @@ gcc_jit_function_new_local (gcc_jit_function *func,
 			    gcc_jit_type *type,
 			    const char *name);
 
+extern gcc_jit_lvalue *
+gcc_jit_function_new_temp (gcc_jit_function *func,
+			   gcc_jit_location *loc,
+			   gcc_jit_type *type);
+
+#define LIBGCCJIT_HAVE_gcc_jit_function_new_temp
+
 /**********************************************************************
  Statement-creation.
  **********************************************************************/

gcc/jit/libgccjit.map

@@ -342,3 +342,8 @@ LIBGCCJIT_ABI_36 {
   global:
     gcc_jit_context_set_output_ident;
 } LIBGCCJIT_ABI_35;
+
+LIBGCCJIT_ABI_37 {
+  global:
+    gcc_jit_function_new_temp;
+} LIBGCCJIT_ABI_36;

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

@@ -322,6 +322,9 @@
 /* test-target-builtins.c: This can't be in the testcases array as it
    is target-specific.  */
 
+/* test-temp.c: This can't be in the testcases array as it
+   is target-specific.  */
+
 /* test-string-literal.c */
 #define create_code create_code_string_literal
 #define verify_code verify_code_string_literal

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

@@ -0,0 +1,56 @@
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <stdint.h>
+
+#include "libgccjit.h"
+
+#define TEST_COMPILING_TO_FILE
+#define OUTPUT_KIND      GCC_JIT_OUTPUT_KIND_ASSEMBLER
+#define OUTPUT_FILENAME  "output-of-test-test-temp.c.s"
+#include "harness.h"
+
+void
+create_code (gcc_jit_context *ctxt, void *user_data)
+{
+  /* Let's try to inject the equivalent of:
+int
+func ()
+{
+   int temp = 10;
+   return temp;
+}
+   */
+  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,
+				  "func",
+				  0, NULL, 0);
+
+  gcc_jit_block *initial =
+    gcc_jit_function_new_block (func, "initial");
+
+  gcc_jit_lvalue *temp =
+    gcc_jit_function_new_temp (func, NULL, int_type);
+
+  gcc_jit_rvalue *ten =
+    gcc_jit_context_new_rvalue_from_int (ctxt, int_type, 10);
+  gcc_jit_block_add_assignment (initial, NULL, temp, ten);
+
+  gcc_jit_block_end_with_return(initial, NULL,
+    gcc_jit_lvalue_as_rvalue (temp));
+}
+
+void
+verify_code (gcc_jit_context *ctxt, gcc_jit_result *result)
+{
+  CHECK_NON_NULL (result);
+}
+
+/* { dg-final { jit-verify-output-file-was-created "" } } */
+/* { dg-final { jit-verify-assembler-output-not "JITTMP" } } */