Return unique_xmalloc_ptr from macro scope functions

This changes the macro scope functions (sal_macro_scope,
user_macro_scope, and default_macro_scope) to return a
unique_xmalloc_ptr, then fixes up the users.  This allowed for the
removal of several cleanups.

2018-02-08  Tom Tromey  <tom@tromey.com>

	* symtab.c (default_collect_symbol_completion_matches_break_on):
	Use unique_xmalloc_ptr.
	* macroscope.h: (sal_macro_scope, user_macro_scope)
	(default_macro_scope): Return unique_xmalloc_ptr.
	* macroscope.c (sal_macro_scope, user_macro_scope)
	(default_macro_scope): Return unique_xmalloc_ptr.
	* macroexp.h (macro_expand, macro_expand_once): Return
	unique_xmalloc_ptr.
	* macroexp.c (macro_expand, macro_expand_once): Return
	unique_xmalloc_ptr.
	* macrocmd.c (macro_expand_command, macro_expand_once_command)
	(info_macro_command, info_macros_command): Use
	unique_xmalloc_ptr.
	* compile/compile-c-support.c (write_macro_definitions): Use
	unique_xmalloc_ptr.
	* c-exp.y (c_parse): Use unique_xmalloc_ptr.

9 files changed, 65 insertions, 75 deletions

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 00ed7e7..49306ac 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,22 @@
+2018-02-08  Tom Tromey  <tom@tromey.com>
+
+	* symtab.c (default_collect_symbol_completion_matches_break_on):
+	Use unique_xmalloc_ptr.
+	* macroscope.h: (sal_macro_scope, user_macro_scope)
+	(default_macro_scope): Return unique_xmalloc_ptr.
+	* macroscope.c (sal_macro_scope, user_macro_scope)
+	(default_macro_scope): Return unique_xmalloc_ptr.
+	* macroexp.h (macro_expand, macro_expand_once): Return
+	unique_xmalloc_ptr.
+	* macroexp.c (macro_expand, macro_expand_once): Return
+	unique_xmalloc_ptr.
+	* macrocmd.c (macro_expand_command, macro_expand_once_command)
+	(info_macro_command, info_macros_command): Use
+	unique_xmalloc_ptr.
+	* compile/compile-c-support.c (write_macro_definitions): Use
+	unique_xmalloc_ptr.
+	* c-exp.y (c_parse): Use unique_xmalloc_ptr.
+
 2018-02-07  Simon Marchi  <simon.marchi@ericsson.com>
 
 	* value.c (value_static_field): Assign field type instead of
diff --git a/gdb/c-exp.y b/gdb/c-exp.y
index 8f0aa00..8dc3c06 100644
--- a/gdb/c-exp.y
+++ b/gdb/c-exp.y
@@ -3220,26 +3220,24 @@ c_parse (struct parser_state *par_state)
   gdb_assert (par_state != NULL);
   pstate = par_state;
 
-  /* Note that parsing (within yyparse) freely installs cleanups
-     assuming they'll be run here (below).  */
-
-  back_to = make_cleanup (free_current_contents, &expression_macro_scope);
-
-  /* Set up the scope for macro expansion.  */
-  expression_macro_scope = NULL;
+  gdb::unique_xmalloc_ptr<struct macro_scope> macro_scope;
 
   if (expression_context_block)
-    expression_macro_scope
-      = sal_macro_scope (find_pc_line (expression_context_pc, 0));
+    macro_scope = sal_macro_scope (find_pc_line (expression_context_pc, 0));
   else
-    expression_macro_scope = default_macro_scope ();
-  if (! expression_macro_scope)
-    expression_macro_scope = user_macro_scope ();
+    macro_scope = default_macro_scope ();
+  if (! macro_scope)
+    macro_scope = user_macro_scope ();
+
+  scoped_restore restore_macro_scope
+    = make_scoped_restore (&expression_macro_scope, macro_scope.get ());
 
   /* Initialize macro expansion code.  */
   obstack_init (&expansion_obstack);
   gdb_assert (! macro_original_text);
-  make_cleanup (scan_macro_cleanup, 0);
+  /* Note that parsing (within yyparse) freely installs cleanups
+     assuming they'll be run here (below).  */
+  back_to = make_cleanup (scan_macro_cleanup, 0);
 
   scoped_restore restore_yydebug = make_scoped_restore (&yydebug,
 							parser_debug);
diff --git a/gdb/compile/compile-c-support.c b/gdb/compile/compile-c-support.c
index 006d3f8..e694648 100644
--- a/gdb/compile/compile-c-support.c
+++ b/gdb/compile/compile-c-support.c
@@ -157,7 +157,7 @@ static void
 write_macro_definitions (const struct block *block, CORE_ADDR pc,
 			 struct ui_file *file)
 {
-  struct macro_scope *scope;
+  gdb::unique_xmalloc_ptr<struct macro_scope> scope;
 
   if (block != NULL)
     scope = sal_macro_scope (find_pc_line (pc, 0));
diff --git a/gdb/macrocmd.c b/gdb/macrocmd.c
index e90d787..13fd95d 100644
--- a/gdb/macrocmd.c
+++ b/gdb/macrocmd.c
@@ -55,11 +55,8 @@ macro_inform_no_debuginfo (void)
 static void
 macro_expand_command (const char *exp, int from_tty)
 {
-  struct macro_scope *ms = NULL;
-  char *expanded = NULL;
-  struct cleanup *cleanup_chain = make_cleanup (free_current_contents, &ms);
-
-  make_cleanup (free_current_contents, &expanded);
+  gdb::unique_xmalloc_ptr<struct macro_scope> ms;
+  gdb::unique_xmalloc_ptr<char> expanded;
 
   /* You know, when the user doesn't specify any expression, it would be
      really cool if this defaulted to the last expression evaluated.
@@ -74,26 +71,21 @@ macro_expand_command (const char *exp, int from_tty)
   ms = default_macro_scope ();
   if (ms)
     {
-      expanded = macro_expand (exp, standard_macro_lookup, ms);
+      expanded = macro_expand (exp, standard_macro_lookup, ms.get ());
       fputs_filtered ("expands to: ", gdb_stdout);
-      fputs_filtered (expanded, gdb_stdout);
+      fputs_filtered (expanded.get (), gdb_stdout);
       fputs_filtered ("\n", gdb_stdout);
     }
   else
     macro_inform_no_debuginfo ();
-
-  do_cleanups (cleanup_chain);
-  return;
 }
 
 
 static void
 macro_expand_once_command (const char *exp, int from_tty)
 {
-  struct macro_scope *ms = NULL;
-  char *expanded = NULL;
-  struct cleanup *cleanup_chain = make_cleanup (free_current_contents, &ms);
-  make_cleanup (free_current_contents, &expanded);
+  gdb::unique_xmalloc_ptr<struct macro_scope> ms;
+  gdb::unique_xmalloc_ptr<char> expanded;
 
   /* You know, when the user doesn't specify any expression, it would be
      really cool if this defaulted to the last expression evaluated.
@@ -108,16 +100,13 @@ macro_expand_once_command (const char *exp, int from_tty)
   ms = default_macro_scope ();
   if (ms)
     {
-      expanded = macro_expand_once (exp, standard_macro_lookup, ms);
+      expanded = macro_expand_once (exp, standard_macro_lookup, ms.get ());
       fputs_filtered ("expands to: ", gdb_stdout);
-      fputs_filtered (expanded, gdb_stdout);
+      fputs_filtered (expanded.get (), gdb_stdout);
       fputs_filtered ("\n", gdb_stdout);
     }
   else
     macro_inform_no_debuginfo ();
-
-  do_cleanups (cleanup_chain);
-  return;
 }
 
 /*  Outputs the include path of a macro starting at FILE and LINE to STREAM.
@@ -190,8 +179,7 @@ print_macro_definition (const char *name,
 static void
 info_macro_command (const char *args, int from_tty)
 {
-  struct macro_scope *ms = NULL;
-  struct cleanup *cleanup_chain;
+  gdb::unique_xmalloc_ptr<struct macro_scope> ms;
   const char *name;
   int show_all_macros_named = 0;
   const char *arg_start = args;
@@ -228,7 +216,6 @@ info_macro_command (const char *args, int from_tty)
 	     "whose definition you want to see."));
 
   ms = default_macro_scope ();
-  cleanup_chain = make_cleanup (free_current_contents, &ms);
 
   if (! ms)
     macro_inform_no_debuginfo ();
@@ -263,16 +250,13 @@ info_macro_command (const char *args, int from_tty)
           show_pp_source_pos (gdb_stdout, ms->file, ms->line);
 	}
     }
-
-  do_cleanups (cleanup_chain);
 }
 
 /* Implementation of the "info macros" command. */
 static void
 info_macros_command (const char *args, int from_tty)
 {
-  struct macro_scope *ms = NULL;
-  struct cleanup *cleanup_chain = make_cleanup (free_current_contents, &ms);
+  gdb::unique_xmalloc_ptr<struct macro_scope> ms;
 
   if (args == NULL)
     ms = default_macro_scope ();
@@ -289,8 +273,6 @@ info_macros_command (const char *args, int from_tty)
     macro_inform_no_debuginfo ();
   else
     macro_for_each_in_scope (ms->file, ms->line, print_macro_definition);
-
-  do_cleanups (cleanup_chain);
 }
 
 
diff --git a/gdb/macroexp.c b/gdb/macroexp.c
index 8a2df1e..aefb13a 100644
--- a/gdb/macroexp.c
+++ b/gdb/macroexp.c
@@ -1485,7 +1485,7 @@ scan (struct macro_buffer *dest,
 }
 
 
-char *
+gdb::unique_xmalloc_ptr<char>
 macro_expand (const char *source,
               macro_lookup_ftype *lookup_func,
               void *lookup_func_baton)
@@ -1504,11 +1504,11 @@ macro_expand (const char *source,
   appendc (&dest, '\0');
 
   discard_cleanups (back_to);
-  return dest.text;
+  return gdb::unique_xmalloc_ptr<char> (dest.text);
 }
 
 
-char *
+gdb::unique_xmalloc_ptr<char>
 macro_expand_once (const char *source,
                    macro_lookup_ftype *lookup_func,
                    void *lookup_func_baton)
diff --git a/gdb/macroexp.h b/gdb/macroexp.h
index f7c7411..8d3e3f0 100644
--- a/gdb/macroexp.h
+++ b/gdb/macroexp.h
@@ -37,9 +37,9 @@ typedef struct macro_definition *(macro_lookup_ftype) (const char *name,
    preprocessor definitions.  SOURCE is a null-terminated string.  The
    result is a null-terminated string, allocated using xmalloc; it is
    the caller's responsibility to free it.  */
-char *macro_expand (const char *source,
-                    macro_lookup_ftype *lookup_func,
-                    void *lookup_func_baton);
+gdb::unique_xmalloc_ptr<char> macro_expand (const char *source,
+					    macro_lookup_ftype *lookup_func,
+					    void *lookup_func_baton);
 
 
 /* Expand all preprocessor macro references that appear explicitly in
@@ -49,9 +49,9 @@ char *macro_expand (const char *source,
    SOURCE is a null-terminated string.  The result is a
    null-terminated string, allocated using xmalloc; it is the caller's
    responsibility to free it.  */
-char *macro_expand_once (const char *source,
-                         macro_lookup_ftype *lookup_func,
-                         void *lookup_func_baton);
+gdb::unique_xmalloc_ptr<char> macro_expand_once (const char *source,
+						 macro_lookup_ftype *lookup_func,
+						 void *lookup_func_baton);
 
 
 /* If the null-terminated string pointed to by *LEXPTR begins with a
diff --git a/gdb/macroscope.c b/gdb/macroscope.c
index a944920..23d2e50 100644
--- a/gdb/macroscope.c
+++ b/gdb/macroscope.c
@@ -35,11 +35,10 @@
 struct macro_table *macro_user_macros;
 
 
-struct macro_scope *
+gdb::unique_xmalloc_ptr<struct macro_scope>
 sal_macro_scope (struct symtab_and_line sal)
 {
   struct macro_source_file *main_file, *inclusion;
-  struct macro_scope *ms;
   struct compunit_symtab *cust;
 
   if (sal.symtab == NULL)
@@ -48,7 +47,7 @@ sal_macro_scope (struct symtab_and_line sal)
   if (COMPUNIT_MACRO_TABLE (cust) == NULL)
     return NULL;
 
-  ms = XNEW (struct macro_scope);
+  gdb::unique_xmalloc_ptr<struct macro_scope> ms (XNEW (struct macro_scope));
 
   main_file = macro_main (COMPUNIT_MACRO_TABLE (cust));
   inclusion = macro_lookup_inclusion (main_file, sal.symtab->filename);
@@ -87,22 +86,20 @@ sal_macro_scope (struct symtab_and_line sal)
 }
 
 
-struct macro_scope *
+gdb::unique_xmalloc_ptr<struct macro_scope>
 user_macro_scope (void)
 {
-  struct macro_scope *ms;
-
-  ms = XNEW (struct macro_scope);
+  gdb::unique_xmalloc_ptr<struct macro_scope> ms (XNEW (struct macro_scope));
   ms->file = macro_main (macro_user_macros);
   ms->line = -1;
   return ms;
 }
 
-struct macro_scope *
+gdb::unique_xmalloc_ptr<struct macro_scope>
 default_macro_scope (void)
 {
   struct symtab_and_line sal;
-  struct macro_scope *ms;
+  gdb::unique_xmalloc_ptr<struct macro_scope> ms;
   struct frame_info *frame;
   CORE_ADDR pc;
 
diff --git a/gdb/macroscope.h b/gdb/macroscope.h
index 3bd1c9e..00fa98a 100644
--- a/gdb/macroscope.h
+++ b/gdb/macroscope.h
@@ -39,13 +39,13 @@ struct macro_scope {
 /* Return a `struct macro_scope' object corresponding to the symtab
    and line given in SAL.  If we have no macro information for that
    location, or if SAL's pc is zero, return zero.  */
-struct macro_scope *sal_macro_scope (struct symtab_and_line sal);
+gdb::unique_xmalloc_ptr<struct macro_scope> sal_macro_scope
+    (struct symtab_and_line sal);
 
 
 /* Return a `struct macro_scope' object representing just the
-   user-defined macros.  The result is allocated using xmalloc; the
-   caller is responsible for freeing it.  */
-struct macro_scope *user_macro_scope (void);
+   user-defined macros.  */
+gdb::unique_xmalloc_ptr<struct macro_scope> user_macro_scope (void);
 
 /* Return a `struct macro_scope' object describing the scope the `macro
    expand' and `macro expand-once' commands should use for looking up
@@ -53,11 +53,8 @@ struct macro_scope *user_macro_scope (void);
    its PC; otherwise, this is the last listing position.
 
    If we have no macro information for the current location, return
-   the user macro scope.
-
-   The object returned is allocated using xmalloc; the caller is
-   responsible for freeing it.  */
-struct macro_scope *default_macro_scope (void);
+   the user macro scope.  */
+gdb::unique_xmalloc_ptr<struct macro_scope> default_macro_scope (void);
 
 
 /* Look up the definition of the macro named NAME in scope at the source
diff --git a/gdb/symtab.c b/gdb/symtab.c
index 81f4fc9..0fd3f3a 100644
--- a/gdb/symtab.c
+++ b/gdb/symtab.c
@@ -5154,7 +5154,7 @@ default_collect_symbol_completion_matches_break_on
   if (current_language->la_macro_expansion == macro_expansion_c
       && code == TYPE_CODE_UNDEF)
     {
-      struct macro_scope *scope;
+      gdb::unique_xmalloc_ptr<struct macro_scope> scope;
 
       /* This adds a macro's name to the current completion list.  */
       auto add_macro_name = [&] (const char *macro_name,
@@ -5175,11 +5175,8 @@ default_collect_symbol_completion_matches_break_on
 	 completion time.  */
       scope = default_macro_scope ();
       if (scope)
-	{
-	  macro_for_each_in_scope (scope->file, scope->line,
-				   add_macro_name);
-	  xfree (scope);
-	}
+	macro_for_each_in_scope (scope->file, scope->line,
+				 add_macro_name);
 
       /* User-defined macros are always visible.  */
       macro_for_each (macro_user_macros, add_macro_name);