gdb/jit: split jit_objfile_data in two

The jit_objfile_data is currently used to hold information about both
objfiles that are the result of JIT compilation (JITed) and objfiles
that can produce JITed objfiles (JITers).  I think that this double use
of the type is confusing, and that things would be more obvious if we
had one type for each role.

This patch splits it into:

- jited_objfile_data: for data about an objfile that is the result of a
  JIT compilation
- jiter_objfile_data: for data about an objfile which produces JITed
  objfiles

There are now two JIT-related fields in an objfile, one for each kind.
With this change, the following invariants hold:

- an objfile has a non-null `jiter_data` field iff it defines the required
  symbols of the JIT interface
- an objfile has a non-null `jited_data` field iff it is the product of
  JIT compilation (has been produced by some JITer)

gdb/ChangeLog:
2020-07-22  Simon Marchi  <simon.marchi@polymtl.ca>

	* jit.h (struct jit_objfile_data):  Split into...
	(struct jiter_objfile_data): ... this ...
	(struct jited_objfile_data): ... and this.
	* objfiles.h (struct objfile) <jit_data>: Remove.
	<jiter_data, jited_data>: New fields.
	* jit.c (jit_objfile_data::~jit_objfile_data): Rename to ...
	(jiter_objfile_data::~jiter_objfile_data): ... this.
	(get_jit_objfile_data): Rename to ...
	(get_jiter_objfile_data): ... this.
	(add_objfile_entry): Update.
	(jit_read_descriptor): Use get_jiter_objfile_data.
	(jit_find_objf_with_entry_addr): Use objfile's jited_data field.
	(jit_breakpoint_re_set_internal): Use get_jiter_objfile_data.
	(jit_inferior_exit_hook): Use objfile's jited_data field.

4 files changed, 57 insertions, 31 deletions

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index ed90071..54b75aa 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,5 +1,22 @@
 2020-07-22  Simon Marchi  <simon.marchi@polymtl.ca>
 
+	* jit.h (struct jit_objfile_data):  Split into...
+	(struct jiter_objfile_data): ... this ...
+	(struct jited_objfile_data): ... and this.
+	* objfiles.h (struct objfile) <jit_data>: Remove.
+	<jiter_data, jited_data>: New fields.
+	* jit.c (jit_objfile_data::~jit_objfile_data): Rename to ...
+	(jiter_objfile_data::~jiter_objfile_data): ... this.
+	(get_jit_objfile_data): Rename to ...
+	(get_jiter_objfile_data): ... this.
+	(add_objfile_entry): Update.
+	(jit_read_descriptor): Use get_jiter_objfile_data.
+	(jit_find_objf_with_entry_addr): Use objfile's jited_data field.
+	(jit_breakpoint_re_set_internal): Use get_jiter_objfile_data.
+	(jit_inferior_exit_hook): Use objfile's jited_data field.
+
+2020-07-22  Simon Marchi  <simon.marchi@polymtl.ca>
+
 	* jit.h: Forward-declare `struct minimal_symbol`.
 	(struct jit_objfile_data): Migrate to here from jit.c; also add a
 	constructor, destructor, and an objfile* field.
diff --git a/gdb/jit.c b/gdb/jit.c
index 39e3641..7c8bfcb 100644
--- a/gdb/jit.c
+++ b/gdb/jit.c
@@ -263,9 +263,9 @@ struct jit_program_space_data
 
 static program_space_key<jit_program_space_data> jit_program_space_key;
 
-/* Destructor for jit_objfile_data.  */
+/* Destructor for jiter_objfile_data.  */
 
-jit_objfile_data::~jit_objfile_data ()
+jiter_objfile_data::~jiter_objfile_data ()
 {
   /* Free the data allocated in the jit_program_space_data slot.  */
   if (this->register_code != NULL)
@@ -283,16 +283,16 @@ jit_objfile_data::~jit_objfile_data ()
     }
 }
 
-/* Fetch the jit_objfile_data associated with OBJF.  If no data exists
+/* Fetch the jiter_objfile_data associated with OBJF.  If no data exists
    yet, make a new structure and attach it.  */
 
-static struct jit_objfile_data *
-get_jit_objfile_data (struct objfile *objf)
+static jiter_objfile_data *
+get_jiter_objfile_data (objfile *objf)
 {
-  if (objf->jit_data == nullptr)
-    objf->jit_data.reset (new jit_objfile_data (objf));
+  if (objf->jiter_data == nullptr)
+    objf->jiter_data.reset (new jiter_objfile_data (objf));
 
-  return objf->jit_data.get ();
+  return objf->jiter_data.get ();
 }
 
 /* Remember OBJFILE has been created for struct jit_code_entry located
@@ -301,10 +301,9 @@ get_jit_objfile_data (struct objfile *objf)
 static void
 add_objfile_entry (struct objfile *objfile, CORE_ADDR entry)
 {
-  struct jit_objfile_data *objf_data;
+  gdb_assert (objfile->jited_data == nullptr);
 
-  objf_data = get_jit_objfile_data (objfile);
-  objf_data->addr = entry;
+  objfile->jited_data.reset (new jited_objfile_data (entry));
 }
 
 /* Return jit_program_space_data for current program space.  Allocate
@@ -335,10 +334,9 @@ jit_read_descriptor (gdbarch *gdbarch,
   int desc_size;
   gdb_byte *desc_buf;
   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
-  struct jit_objfile_data *objf_data;
 
   gdb_assert (jiter != nullptr);
-  objf_data = get_jit_objfile_data (jiter);
+  jiter_objfile_data *objf_data = get_jiter_objfile_data (jiter);
 
   if (objf_data->descriptor == NULL)
     return false;
@@ -908,7 +906,7 @@ jit_find_objf_with_entry_addr (CORE_ADDR entry_addr)
 {
   for (objfile *objf : current_program_space->objfiles ())
     {
-      if (objf->jit_data != nullptr && objf->jit_data->addr == entry_addr)
+      if (objf->jited_data != nullptr && objf->jited_data->addr == entry_addr)
 	return objf;
     }
 
@@ -948,7 +946,7 @@ jit_breakpoint_re_set_internal (struct gdbarch *gdbarch,
 {
   struct bound_minimal_symbol reg_symbol;
   struct bound_minimal_symbol desc_symbol;
-  struct jit_objfile_data *objf_data;
+  jiter_objfile_data *objf_data;
   CORE_ADDR addr;
 
   if (ps_data->objfile == NULL)
@@ -966,14 +964,14 @@ jit_breakpoint_re_set_internal (struct gdbarch *gdbarch,
 	  || BMSYMBOL_VALUE_ADDRESS (desc_symbol) == 0)
 	return false;
 
-      objf_data = get_jit_objfile_data (reg_symbol.objfile);
+      objf_data = get_jiter_objfile_data (reg_symbol.objfile);
       objf_data->register_code = reg_symbol.minsym;
       objf_data->descriptor = desc_symbol.minsym;
 
       ps_data->objfile = reg_symbol.objfile;
     }
   else
-    objf_data = get_jit_objfile_data (ps_data->objfile);
+    objf_data = get_jiter_objfile_data (ps_data->objfile);
 
   addr = MSYMBOL_VALUE_ADDRESS (ps_data->objfile, objf_data->register_code);
 
@@ -1315,7 +1313,7 @@ jit_inferior_exit_hook (struct inferior *inf)
 {
   for (objfile *objf : current_program_space->objfiles_safe ())
     {
-      if (objf->jit_data != nullptr && objf->jit_data->addr != 0)
+      if (objf->jited_data != nullptr && objf->jited_data->addr != 0)
 	objf->unlink ();
     }
 }
diff --git a/gdb/jit.h b/gdb/jit.h
index 6109216..fcef78d 100644
--- a/gdb/jit.h
+++ b/gdb/jit.h
@@ -67,19 +67,16 @@ struct jit_descriptor
   CORE_ADDR first_entry;
 };
 
-/* Per-objfile structure recording the addresses in the program space.
-   This object serves two purposes: for ordinary objfiles, it may
-   cache some symbols related to the JIT interface; and for
-   JIT-created objfiles, it holds some information about the
-   jit_code_entry.  */
+/* An objfile that defines the required symbols of the JIT interface has an
+   instance of this type attached to it.  */
 
-struct jit_objfile_data
+struct jiter_objfile_data
 {
-  jit_objfile_data (struct objfile *objfile)
+  jiter_objfile_data (struct objfile *objfile)
     : objfile (objfile)
   {}
 
-  ~jit_objfile_data ();
+  ~jiter_objfile_data ();
 
   /* Back-link to the objfile. */
   struct objfile *objfile;
@@ -89,10 +86,19 @@ struct jit_objfile_data
 
   /* Symbol for __jit_debug_descriptor.  */
   minimal_symbol *descriptor = nullptr;
+};
+
+/* An objfile that is the product of JIT compilation and was registered
+   using the JIT interface has an instance of this type attached to it.  */
+
+struct jited_objfile_data
+{
+  jited_objfile_data (CORE_ADDR addr)
+    : addr (addr)
+  {}
 
-  /* Address of struct jit_code_entry in this objfile.  This is only
-     non-zero for objfiles that represent code created by the JIT.  */
-  CORE_ADDR addr = 0;
+  /* Address of struct jit_code_entry for this objfile.  */
+  CORE_ADDR addr;
 };
 
 /* Looks for the descriptor and registration symbols and breakpoints
diff --git a/gdb/objfiles.h b/gdb/objfiles.h
index b21b426..3fbc6da 100644
--- a/gdb/objfiles.h
+++ b/gdb/objfiles.h
@@ -699,8 +699,13 @@ public:
      allocated on the objfile's obstack.  */
   htab_up static_links;
 
-  /* JIT-related data for this objfile.  */
-  std::unique_ptr<jit_objfile_data> jit_data = nullptr;
+  /* JIT-related data for this objfile, if the objfile is a JITer;
+     that is, it produces JITed objfiles.  */
+  std::unique_ptr<jiter_objfile_data> jiter_data = nullptr;
+
+  /* JIT-related data for this objfile, if the objfile is JITed;
+     that is, it was produced by a JITer.  */
+  std::unique_ptr<jited_objfile_data> jited_data = nullptr;
 };
 
 /* A deleter for objfile.  */