gdb: Convert language la_get_compile_instance field to a method

This commit changes the language_data::la_get_compile_instance
function pointer member variable into a member function of
language_defn.  Unlike previous commits converting fields of
language_data to member function in language_defn, this field is NULL
for some languages.  As a result I had to change the API slightly so
that the base language_defn class provides an implementation.

There should be no user visible changes after this commit.

gdb/ChangeLog:

	* ada-lang.c (ada_language_data): Delete la_get_compile_instance
	initializer.
	* c-lang.c (class compile_instance): Declare.
	(c_language_data): Delete la_get_compile_instance initializer.
	(c_language::get_compile_instance): New member function.
	(cplus_language_data): Delete la_get_compile_instance initializer.
	(cplus_language::get_compile_instance): New member function.
	(asm_language_data): Delete la_get_compile_instance initializer.
	(minimal_language_data): Likewise.
	* c-lang.h (c_get_compile_context): Update comment.
	(cplus_get_compile_context): Update comment.
	* compile/compile.c (compile_to_object): Update calls, don't rely
	on function pointer being NULL.
	* d-lang.c (d_language_data): Delete la_get_compile_instance
	initializer.
	* f-lang.c (f_language_data): Likewise.
	* go-lang.c (go_language_data): Likewise.
	* language.c (unknown_language_data): Likewise.
	(auto_language_data): Likewise.
	* language.h (language_data): Delete la_get_compile_instance field.
	(language_defn::get_compile_instance): New member function.
	* m2-lang.c (m2_language_data): Delete la_get_compile_instance
	initializer.
	* objc-lang.c (objc_language_data): Likewise.
	* opencl-lang.c (opencl_language_data): Likewise.
	* p-lang.c (pascal_language_data): Likewise.
	* rust-lang.c (rust_language_data): Likewise.

15 files changed, 62 insertions, 32 deletions

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 34c5581..a05b6b1 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,5 +1,35 @@
 2020-06-02  Andrew Burgess  <andrew.burgess@embecosm.com>
 
+	* ada-lang.c (ada_language_data): Delete la_get_compile_instance
+	initializer.
+	* c-lang.c (class compile_instance): Declare.
+	(c_language_data): Delete la_get_compile_instance initializer.
+	(c_language::get_compile_instance): New member function.
+	(cplus_language_data): Delete la_get_compile_instance initializer.
+	(cplus_language::get_compile_instance): New member function.
+	(asm_language_data): Delete la_get_compile_instance initializer.
+	(minimal_language_data): Likewise.
+	* c-lang.h (c_get_compile_context): Update comment.
+	(cplus_get_compile_context): Update comment.
+	* compile/compile.c (compile_to_object): Update calls, don't rely
+	on function pointer being NULL.
+	* d-lang.c (d_language_data): Delete la_get_compile_instance
+	initializer.
+	* f-lang.c (f_language_data): Likewise.
+	* go-lang.c (go_language_data): Likewise.
+	* language.c (unknown_language_data): Likewise.
+	(auto_language_data): Likewise.
+	* language.h (language_data): Delete la_get_compile_instance field.
+	(language_defn::get_compile_instance): New member function.
+	* m2-lang.c (m2_language_data): Delete la_get_compile_instance
+	initializer.
+	* objc-lang.c (objc_language_data): Likewise.
+	* opencl-lang.c (opencl_language_data): Likewise.
+	* p-lang.c (pascal_language_data): Likewise.
+	* rust-lang.c (rust_language_data): Likewise.
+
+2020-06-02  Andrew Burgess  <andrew.burgess@embecosm.com>
+
 	* ada-lang.c (ada_add_all_symbols): Update comment.
 	(ada_iterate_over_symbols): Delete, move implementation to...
 	(ada_language::iterate_over_symbols): ...here, a new member
diff --git a/gdb/ada-lang.c b/gdb/ada-lang.c
index 762c124..f0f5ee5 100644
--- a/gdb/ada-lang.c
+++ b/gdb/ada-lang.c
@@ -13980,7 +13980,6 @@ extern const struct language_data ada_language_data =
   default_search_name_hash,
   &ada_varobj_ops,
   NULL,
-  NULL,
   ada_is_string_type,
   "(...)"			/* la_struct_too_deep_ellipsis */
 };
diff --git a/gdb/c-lang.c b/gdb/c-lang.c
index bfd45f4..eb9ebdb 100644
--- a/gdb/c-lang.c
+++ b/gdb/c-lang.c
@@ -37,6 +37,8 @@
 #include "gdbcore.h"
 #include "gdbarch.h"
 
+class compile_instance;
+
 /* Given a C string type, STR_TYPE, return the corresponding target
    character set name.  */
 
@@ -924,7 +926,6 @@ extern const struct language_data c_language_data =
   NULL,				/* la_get_symbol_name_matcher */
   default_search_name_hash,
   &c_varobj_ops,
-  c_get_compile_context,
   c_compute_program,
   c_is_string_type_p,
   "{...}"			/* la_struct_too_deep_ellipsis */
@@ -945,6 +946,12 @@ public:
   {
     c_language_arch_info (gdbarch, lai);
   }
+
+  /* See language.h.  */
+  compile_instance *get_compile_instance () const override
+  {
+    return c_get_compile_context ();
+  }
 };
 
 /* Single instance of the C language class.  */
@@ -1023,7 +1030,6 @@ extern const struct language_data cplus_language_data =
   cp_get_symbol_name_matcher,
   cp_search_name_hash,
   &cplus_varobj_ops,
-  cplus_get_compile_context,
   cplus_compute_program,
   c_is_string_type_p,
   "{...}"			/* la_struct_too_deep_ellipsis */
@@ -1114,6 +1120,12 @@ public:
   {
     return cp_lookup_transparent_type (name);
   }
+
+  /* See language.h.  */
+  compile_instance *get_compile_instance () const override
+  {
+    return cplus_get_compile_context ();
+  }
 };
 
 /* The single instance of the C++ language class.  */
@@ -1165,7 +1177,6 @@ extern const struct language_data asm_language_data =
   default_search_name_hash,
   &default_varobj_ops,
   NULL,
-  NULL,
   c_is_string_type_p,
   "{...}"			/* la_struct_too_deep_ellipsis */
 };
@@ -1235,7 +1246,6 @@ extern const struct language_data minimal_language_data =
   default_search_name_hash,
   &default_varobj_ops,
   NULL,
-  NULL,
   c_is_string_type_p,
   "{...}"			/* la_struct_too_deep_ellipsis */
 };
diff --git a/gdb/c-lang.h b/gdb/c-lang.h
index 6421571..3e07dc9 100644
--- a/gdb/c-lang.h
+++ b/gdb/c-lang.h
@@ -157,7 +157,7 @@ extern int c_textual_element_type (struct type *, char);
    compiler is owned by the caller and must be freed using the destroy
    method.  This function never returns NULL, but rather throws an
    exception on failure.  This is suitable for use as the
-   la_get_compile_instance language method.  */
+   language_defn::get_compile_instance method.  */
 
 extern compile_instance *c_get_compile_context (void);
 
@@ -165,7 +165,7 @@ extern compile_instance *c_get_compile_context (void);
    compiler is owned by the caller and must be freed using the destroy
    method.  This function never returns NULL, but rather throws an
    exception on failure.  This is suitable for use as the
-   la_get_compile_instance language method.  */
+   language_defn::get_compile_instance method.  */
 
 extern compile_instance *cplus_get_compile_context ();
 
diff --git a/gdb/compile/compile.c b/gdb/compile/compile.c
index 8d134d9..3a3afa8 100644
--- a/gdb/compile/compile.c
+++ b/gdb/compile/compile.c
@@ -691,13 +691,11 @@ compile_to_object (struct command_line *cmd, const char *cmd_string,
   expr_pc = get_frame_address_in_block (get_selected_frame (NULL));
 
   /* Set up instance and context for the compiler.  */
-  if (current_language->la_get_compile_instance == NULL)
+  std::unique_ptr <compile_instance> compiler
+			(current_language->get_compile_instance ());
+  if (compiler == nullptr)
     error (_("No compiler support for language %s."),
 	   current_language->la_name);
-
-  compile_instance *compiler_instance
-    = current_language->la_get_compile_instance ();
-  std::unique_ptr<compile_instance> compiler (compiler_instance);
   compiler->set_print_callback (print_callback, NULL);
   compiler->set_scope (scope);
   compiler->set_block (expr_block);
diff --git a/gdb/d-lang.c b/gdb/d-lang.c
index 5732778..08b884d 100644
--- a/gdb/d-lang.c
+++ b/gdb/d-lang.c
@@ -179,7 +179,6 @@ extern const struct language_data d_language_data =
   default_search_name_hash,
   &default_varobj_ops,
   NULL,
-  NULL,
   c_is_string_type_p,
   "{...}"			/* la_struct_too_deep_ellipsis */
 };
diff --git a/gdb/f-lang.c b/gdb/f-lang.c
index ae559de..9e647f5 100644
--- a/gdb/f-lang.c
+++ b/gdb/f-lang.c
@@ -636,7 +636,6 @@ extern const struct language_data f_language_data =
   cp_search_name_hash,
   &default_varobj_ops,
   NULL,
-  NULL,
   f_is_string_type_p,
   "(...)"			/* la_struct_too_deep_ellipsis */
 };
diff --git a/gdb/go-lang.c b/gdb/go-lang.c
index c596279..8f9ea63 100644
--- a/gdb/go-lang.c
+++ b/gdb/go-lang.c
@@ -564,7 +564,6 @@ extern const struct language_data go_language_data =
   default_search_name_hash,
   &default_varobj_ops,
   NULL,
-  NULL,
   go_is_string_type_p,
   "{...}"			/* la_struct_too_deep_ellipsis */
 };
diff --git a/gdb/language.c b/gdb/language.c
index 33e8b16..941e0df 100644
--- a/gdb/language.c
+++ b/gdb/language.c
@@ -841,7 +841,6 @@ extern const struct language_data unknown_language_data =
   default_search_name_hash,
   &default_varobj_ops,
   NULL,
-  NULL,
   default_is_string_type_p,
   "{...}"			/* la_struct_too_deep_ellipsis */
 };
@@ -907,7 +906,6 @@ extern const struct language_data auto_language_data =
   default_search_name_hash,
   &default_varobj_ops,
   NULL,
-  NULL,
   default_is_string_type_p,
   "{...}"			/* la_struct_too_deep_ellipsis */
 };
diff --git a/gdb/language.h b/gdb/language.h
index 0880ced..57f0adb 100644
--- a/gdb/language.h
+++ b/gdb/language.h
@@ -392,16 +392,6 @@ struct language_data
     /* Various operations on varobj.  */
     const struct lang_varobj_ops *la_varobj_ops;
 
-    /* If this language allows compilation from the gdb command line,
-       this method should be non-NULL.  When called it should return
-       an instance of struct gcc_context appropriate to the language.
-       When defined this method must never return NULL; instead it
-       should throw an exception on failure.  The returned compiler
-       instance is owned by its caller and must be deallocated by
-       calling its 'destroy' method.  */
-
-    compile_instance *(*la_get_compile_instance) (void);
-
     /* This method must be defined if 'la_get_gcc_context' is defined.
        If 'la_get_gcc_context' is not defined, then this method is
        ignored.
@@ -511,6 +501,19 @@ struct language_defn : language_data
     return ::iterate_over_symbols (block, name, domain, callback);
   }
 
+  /* If this language allows compilation from the gdb command line, then
+     this method will return an instance of struct gcc_context appropriate
+     to the language.  If compilation for this language is generally
+     supported, but something goes wrong then an exception is thrown.  The
+     returned compiler instance is owned by its caller and must be
+     deallocated by the caller.  If compilation is not supported for this
+     language then this method returns NULL.  */
+
+  virtual compile_instance *get_compile_instance () const
+  {
+    return nullptr;
+  }
+
   /* List of all known languages.  */
   static const struct language_defn *languages[nr_languages];
 };
diff --git a/gdb/m2-lang.c b/gdb/m2-lang.c
index c83f9ef..21cafb9 100644
--- a/gdb/m2-lang.c
+++ b/gdb/m2-lang.c
@@ -389,7 +389,6 @@ extern const struct language_data m2_language_data =
   default_search_name_hash,
   &default_varobj_ops,
   NULL,
-  NULL,
   m2_is_string_type_p,
   "{...}"			/* la_struct_too_deep_ellipsis */
 };
diff --git a/gdb/objc-lang.c b/gdb/objc-lang.c
index 6cf8bbb..4a84f84 100644
--- a/gdb/objc-lang.c
+++ b/gdb/objc-lang.c
@@ -404,7 +404,6 @@ extern const struct language_data objc_language_data =
   default_search_name_hash,
   &default_varobj_ops,
   NULL,
-  NULL,
   c_is_string_type_p,
   "{...}"			/* la_struct_too_deep_ellipsis */
 };
diff --git a/gdb/opencl-lang.c b/gdb/opencl-lang.c
index a548fe6..bfb462c 100644
--- a/gdb/opencl-lang.c
+++ b/gdb/opencl-lang.c
@@ -1064,7 +1064,6 @@ extern const struct language_data opencl_language_data =
   default_search_name_hash,
   &default_varobj_ops,
   NULL,
-  NULL,
   c_is_string_type_p,
   "{...}"			/* la_struct_too_deep_ellipsis */
 };
diff --git a/gdb/p-lang.c b/gdb/p-lang.c
index 7956d87..f040f9a 100644
--- a/gdb/p-lang.c
+++ b/gdb/p-lang.c
@@ -419,7 +419,6 @@ extern const struct language_data pascal_language_data =
   default_search_name_hash,
   &default_varobj_ops,
   NULL,
-  NULL,
   pascal_is_string_type_p,
   "{...}"			/* la_struct_too_deep_ellipsis */
 };
diff --git a/gdb/rust-lang.c b/gdb/rust-lang.c
index 966aa14..fbc454c 100644
--- a/gdb/rust-lang.c
+++ b/gdb/rust-lang.c
@@ -2096,7 +2096,6 @@ extern const struct language_data rust_language_data =
   default_search_name_hash,
   &default_varobj_ops,
   NULL,
-  NULL,
   rust_is_string_type_p,
   "{...}"			/* la_struct_too_deep_ellipsis */
 };