Re: [PATCH] Instantiate a single source highlighter

[Tom Tromey <tromey at adacore dot com>]

>>>>> "Pedro" == Pedro Alves <palves@redhat.com> writes:

>> +/* The global source highlight object, or null if one was never
>> +   constructed.  This is stored here rather than in the class so that
>> +   we don't need to include anything or do conditional compilation in
>> +   source-cache.h.  */
>> +#ifdef HAVE_SOURCE_HIGHLIGHT
>> +static srchilite::SourceHighlight *highlighter;
>> +#endif

Pedro> Should it be a unique_ptr so that valgrind doesn't complain about
Pedro> it leaking when gdb exits?

Philippe says no, so I didn't make this change.

>> +		  highlighter->setStyleFile("esc.style");

Pedro> Preexisting, but missing space before parens.

Fixed.

Pedro> To keep the variable's definition and initialization close by,
Pedro> I'd add a get_highlighter function:

I just moved the global to be a static in the block that uses it.
This seemed just as good and avoided more #ifdefs.

Here's what I'm checking in.

Tom

commit ca0c2edb7577c10c3772c8eed8e253971847ccdc
Author: Tom Tromey <tromey@adacore.com>
Date:   Tue Jun 18 12:18:24 2019 -0600

    Instantiate a single source highlighter
    
    It occurred to me that there's no reason to make a new source
    highlighter each time gdb needs to highlight some source code.
    Instead, a single one can be created and then simply reused each time.
    
    This patch implements this idea.  Tested on x86-64 Fedora 29.
    
    gdb/ChangeLog
    2019-06-19  Tom Tromey  <tromey@adacore.com>
    
            * source-cache.c (highlighter): New global.
            (source_cache::get_source_lines): Create a highlighter on demand.

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 83f47b25701..1aab438d035 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,8 @@
+2019-06-19  Tom Tromey  <tromey@adacore.com>
+
+	* source-cache.c (highlighter): New global.
+	(source_cache::get_source_lines): Create a highlighter on demand.
+
 2019-06-18  Tom de Vries  <tdevries@suse.de>
 
 	PR gdb/24515
diff --git a/gdb/source-cache.c b/gdb/source-cache.c
index 2d5b549d971..86efe83bf9a 100644
--- a/gdb/source-cache.c
+++ b/gdb/source-cache.c
@@ -197,6 +197,13 @@ source_cache::get_source_lines (struct symtab *s, int first_line,
 	  std::ifstream input (fullname);
 	  if (input.is_open ())
 	    {
+	      /* The global source highlight object, or null if one
+		 was never constructed.  This is stored here rather
+		 than in the class so that we don't need to include
+		 anything or do conditional compilation in
+		 source-cache.h.  */
+	      static srchilite::SourceHighlight *highlighter;
+
 	      if (s->line_charpos == 0)
 		{
 		  scoped_fd desc (open_source_file_with_line_charpos (s));
@@ -209,11 +216,15 @@ source_cache::get_source_lines (struct symtab *s, int first_line,
 		     use-after-free.  */
 		  fullname = symtab_to_fullname (s);
 		}
-	      srchilite::SourceHighlight highlighter ("esc.outlang");
-	      highlighter.setStyleFile("esc.style");
+
+	      if (highlighter == nullptr)
+		{
+		  highlighter = new srchilite::SourceHighlight ("esc.outlang");
+		  highlighter->setStyleFile ("esc.style");
+		}
 
 	      std::ostringstream output;
-	      highlighter.highlight (input, output, lang_name, fullname);
+	      highlighter->highlight (input, output, lang_name, fullname);
 
 	      source_text result = { fullname, output.str () };
 	      m_source_map.push_back (std::move (result));