gdb: Remove LANG_MAGIC

The language_defn structure has an la_magic field, this used to be
used as a basic check that the language_defn structure had the
expected layout - at least the end of the structure was where we
expected it to be.

This feature only really makes sense if we imagine GDB dynamically
loading language support from dynamic libraries, where a version
mismatch might cause problems.

However, in current GDB language support is statically built into GDB,
and since this commit:

    commit 47e77640be31fc1a4eb3718f594ed5fd0faff065
    Date:   Thu Jul 20 18:28:01 2017 +0100

        Make language_def O(1)

the existing (if pointless) check of the la_magic field was removed.

There now appears to be no use of the la_magic field, and I propose
that we delete it.

There should be no user visible changes after this commit.

gdb/ChangeLog:

	* ada-lang.c (ada_language_defn): Remove use of LANG_MAGIC.
	* c-lang.c (c_language_defn): Likewise.
	(cplus_language_defn): Likewise.
	(asm_language_defn): Likewise.
	(minimal_language_defn): Likewise.
	* d-lang.c (d_language_defn): Likewise.
	* f-lang.c (f_language_defn): Likewise.
	* go-lang.c (go_language_defn): Likewise.
	* language.c (unknown_language_defn): Likewise.
	(auto_language_defn): Likewise.
	* language.h (struct language_defn): Remove la_magic field.
	(LANG_MAGIC): Delete.
	* m2-lang.c (m2_language_defn): Remove use of LANG_MAGIC.
	* objc-lang.c (objc_language_defn): Likewise.
	* opencl-lang.c (opencl_language_defn): Likewise.
	* p-lang.c (pascal_language_defn): Likewise.
	* rust-lang.c (rust_language_defn): Likewise.

13 files changed, 35 insertions, 38 deletions

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 92a286b..33bcef3 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,23 @@
+2019-04-12  Andrew Burgess  <andrew.burgess@embecosm.com>
+
+	* ada-lang.c (ada_language_defn): Remove use of LANG_MAGIC.
+	* c-lang.c (c_language_defn): Likewise.
+	(cplus_language_defn): Likewise.
+	(asm_language_defn): Likewise.
+	(minimal_language_defn): Likewise.
+	* d-lang.c (d_language_defn): Likewise.
+	* f-lang.c (f_language_defn): Likewise.
+	* go-lang.c (go_language_defn): Likewise.
+	* language.c (unknown_language_defn): Likewise.
+	(auto_language_defn): Likewise.
+	* language.h (struct language_defn): Remove la_magic field.
+	(LANG_MAGIC): Delete.
+	* m2-lang.c (m2_language_defn): Remove use of LANG_MAGIC.
+	* objc-lang.c (objc_language_defn): Likewise.
+	* opencl-lang.c (opencl_language_defn): Likewise.
+	* p-lang.c (pascal_language_defn): Likewise.
+	* rust-lang.c (rust_language_defn): Likewise.
+
 2019-04-11  Andrew Burgess  <andrew.burgess@embecosm.com>
 
 	* riscv-tdep.c (riscv_type_align): New function.
diff --git a/gdb/ada-lang.c b/gdb/ada-lang.c
index c141adb..ccf8ed8 100644
--- a/gdb/ada-lang.c
+++ b/gdb/ada-lang.c
@@ -14380,8 +14380,7 @@ extern const struct language_defn ada_language_defn = {
   default_search_name_hash,
   &ada_varobj_ops,
   NULL,
-  NULL,
-  LANG_MAGIC
+  NULL
 };
 
 /* Command-list for the "set/show ada" prefix command.  */
diff --git a/gdb/c-lang.c b/gdb/c-lang.c
index 36c7502..33506f1 100644
--- a/gdb/c-lang.c
+++ b/gdb/c-lang.c
@@ -873,8 +873,7 @@ extern const struct language_defn c_language_defn =
   default_search_name_hash,
   &c_varobj_ops,
   c_get_compile_context,
-  c_compute_program,
-  LANG_MAGIC
+  c_compute_program
 };
 
 enum cplus_primitive_types {
@@ -1018,8 +1017,7 @@ extern const struct language_defn cplus_language_defn =
   cp_search_name_hash,
   &cplus_varobj_ops,
   cplus_get_compile_context,
-  cplus_compute_program,
-  LANG_MAGIC
+  cplus_compute_program
 };
 
 static const char *asm_extensions[] =
@@ -1072,8 +1070,7 @@ extern const struct language_defn asm_language_defn =
   default_search_name_hash,
   &default_varobj_ops,
   NULL,
-  NULL,
-  LANG_MAGIC
+  NULL
 };
 
 /* The following language_defn does not represent a real language.
@@ -1126,6 +1123,5 @@ extern const struct language_defn minimal_language_defn =
   default_search_name_hash,
   &default_varobj_ops,
   NULL,
-  NULL,
-  LANG_MAGIC
+  NULL
 };
diff --git a/gdb/d-lang.c b/gdb/d-lang.c
index 637e012..08b6380 100644
--- a/gdb/d-lang.c
+++ b/gdb/d-lang.c
@@ -250,8 +250,7 @@ extern const struct language_defn d_language_defn =
   default_search_name_hash,
   &default_varobj_ops,
   NULL,
-  NULL,
-  LANG_MAGIC
+  NULL
 };
 
 /* Build all D language types for the specified architecture.  */
diff --git a/gdb/f-lang.c b/gdb/f-lang.c
index 7bd1196..f3a806e 100644
--- a/gdb/f-lang.c
+++ b/gdb/f-lang.c
@@ -377,8 +377,7 @@ extern const struct language_defn f_language_defn =
   default_search_name_hash,
   &default_varobj_ops,
   NULL,
-  NULL,
-  LANG_MAGIC
+  NULL
 };
 
 static void *
diff --git a/gdb/go-lang.c b/gdb/go-lang.c
index 5af88f8..f74cee4 100644
--- a/gdb/go-lang.c
+++ b/gdb/go-lang.c
@@ -611,8 +611,7 @@ extern const struct language_defn go_language_defn =
   default_search_name_hash,
   &default_varobj_ops,
   NULL,
-  NULL,
-  LANG_MAGIC
+  NULL
 };
 
 static void *
diff --git a/gdb/language.c b/gdb/language.c
index 435243e..954e4c2 100644
--- a/gdb/language.c
+++ b/gdb/language.c
@@ -876,8 +876,7 @@ const struct language_defn unknown_language_defn =
   default_search_name_hash,
   &default_varobj_ops,
   NULL,
-  NULL,
-  LANG_MAGIC
+  NULL
 };
 
 /* These two structs define fake entries for the "local" and "auto"
@@ -927,8 +926,7 @@ const struct language_defn auto_language_defn =
   default_search_name_hash,
   &default_varobj_ops,
   NULL,
-  NULL,
-  LANG_MAGIC
+  NULL
 };
 
 
diff --git a/gdb/language.h b/gdb/language.h
index a982e19..3e0bc9d 100644
--- a/gdb/language.h
+++ b/gdb/language.h
@@ -449,16 +449,8 @@ struct language_defn
 				       struct gdbarch *gdbarch,
 				       const struct block *expr_block,
 				       CORE_ADDR expr_pc);
-
-    /* Add fields above this point, so the magic number is always last.  */
-    /* Magic number for compat checking.  */
-
-    long la_magic;
-
   };
 
-#define LANG_MAGIC	910823L
-
 /* Pointer to the language_defn for our current language.  This pointer
    always points to *some* valid struct; it can be used without checking
    it for validity.
diff --git a/gdb/m2-lang.c b/gdb/m2-lang.c
index 1a72aba..b4eb262 100644
--- a/gdb/m2-lang.c
+++ b/gdb/m2-lang.c
@@ -398,8 +398,7 @@ extern const struct language_defn m2_language_defn =
   default_search_name_hash,
   &default_varobj_ops,
   NULL,
-  NULL,
-  LANG_MAGIC
+  NULL
 };
 
 static void *
diff --git a/gdb/objc-lang.c b/gdb/objc-lang.c
index be1a27f..1853a69 100644
--- a/gdb/objc-lang.c
+++ b/gdb/objc-lang.c
@@ -408,8 +408,7 @@ extern const struct language_defn objc_language_defn = {
   default_search_name_hash,
   &default_varobj_ops,
   NULL,
-  NULL,
-  LANG_MAGIC
+  NULL
 };
 
 /*
diff --git a/gdb/opencl-lang.c b/gdb/opencl-lang.c
index 03699b1..c1ea66e 100644
--- a/gdb/opencl-lang.c
+++ b/gdb/opencl-lang.c
@@ -1086,8 +1086,7 @@ extern const struct language_defn opencl_language_defn =
   default_search_name_hash,
   &default_varobj_ops,
   NULL,
-  NULL,
-  LANG_MAGIC
+  NULL
 };
 
 static void *
diff --git a/gdb/p-lang.c b/gdb/p-lang.c
index b61273f..9340861 100644
--- a/gdb/p-lang.c
+++ b/gdb/p-lang.c
@@ -459,6 +459,5 @@ extern const struct language_defn pascal_language_defn =
   default_search_name_hash,
   &default_varobj_ops,
   NULL,
-  NULL,
-  LANG_MAGIC
+  NULL
 };
diff --git a/gdb/rust-lang.c b/gdb/rust-lang.c
index c3857ee..9a123c3 100644
--- a/gdb/rust-lang.c
+++ b/gdb/rust-lang.c
@@ -2141,6 +2141,5 @@ extern const struct language_defn rust_language_defn =
   default_search_name_hash,
   &default_varobj_ops,
   NULL,
-  NULL,
-  LANG_MAGIC
+  NULL
 };