[PATCH][gdb] Catch exception when constructing the highlighter

[Tom de Vries <tdevries@suse.de>]

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[ was: Re: [PATCH v2 2/2] Add Rust support to source highlighting ]
On 19-09-19 14:54, Tom Tromey wrote:
>>>>>> "Tom" == Tom de Vries <tdevries@suse.de> writes:
> 
> Tom> Well, it does work, but your question makes me realize that that's an
> Tom> implementation artefact of the library, which could change for newer
> Tom> version (or perhaps there are older versions where that differs). So it
> Tom> should be safer to wrap highlighter construction as well.
> 
> Tom> Updated the patch accordingly, and also added a PR number to both patches.
> 
> Looks good to me -- but the bad news is you'll probably now want a
> similar patch on master.

Ok, committed to 8.3 branch.

Here's the proposed commit for master.

Ok for trunk if testing on x86_64-linux finishes without problems?

Thanks,
- Tom


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[gdb] Catch exception when constructing the highlighter

Currently in source_cache::ensure we catch the exception that triggers when
highlighter->highlight is called:
...
         try
           {
             std::istringstream input (contents);
             std::ostringstream output;
             highlighter->highlight (input, output, lang_name, fullname);
...
and the file used earlier in the construction of the highlighter:
...
             highlighter = new srchilite::SourceHighlight ("esc.outlang");
...
is missing.

The fact that this exception triggers when highlighter->highlight is called is
an implementation artefact of libsource-highlight.so though, and this could be
different for older or newer versions.

Make things more robust by also catching exceptions thrown during construction
of the highlighter.  This makes the handling on master equivalent with what
has been committed for 8.3.1.

Tested on x86_64-linux.

gdb/ChangeLog:

2019-09-19  Tom de Vries  <tdevries@suse.de>

	PR gdb/25009
	* source-cache.c (source_cache::ensure): Catch exception thrown during
	construction of the highlighter.

---
 gdb/source-cache.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/gdb/source-cache.c b/gdb/source-cache.c
index 7a52ce9458..1fe6da8132 100644
--- a/gdb/source-cache.c
+++ b/gdb/source-cache.c
@@ -190,14 +190,14 @@ source_cache::ensure (struct symtab *s)
 	     conditional compilation in source-cache.h.  */
 	  static srchilite::SourceHighlight *highlighter;
 
-	  if (highlighter == nullptr)
-	    {
-	      highlighter = new srchilite::SourceHighlight ("esc.outlang");
-	      highlighter->setStyleFile ("esc.style");
-	    }
-
 	  try
 	    {
+	      if (highlighter == nullptr)
+		{
+		  highlighter = new srchilite::SourceHighlight ("esc.outlang");
+		  highlighter->setStyleFile ("esc.style");
+		}
+
 	      std::istringstream input (contents);
 	      std::ostringstream output;
 	      highlighter->highlight (input, output, lang_name, fullname);