[committed] d: Don't escape quoted format strings in escape_d_format (PR101656)

[Iain Buclaw via Gcc-patches]

Hi,

This patch prepares the escape_d_format function to handle being given a
quoted string.  Something that the self-hosted D front-end does with a
new format helper for symbols.

If the format string is enclosed by two '`' characters, then don't
escape the first and laster characters.

There are no tests as only the self-hosted front-end has the necessary
change that turns this on.

Bootstrapped and regression tested on x86_64-linux-gnu/-mx32/-m32, and
committed to mainline.

Regards,
Iain

---
gcc/d/ChangeLog:

        PR d/101656
        * d-diagnostic.cc (escape_d_format): Don't escape quoted format
        strings.
---
 gcc/d/d-diagnostic.cc | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/gcc/d/d-diagnostic.cc b/gcc/d/d-diagnostic.cc
index 7043abe10bd..1982bd954a8 100644
--- a/gcc/d/d-diagnostic.cc
+++ b/gcc/d/d-diagnostic.cc
@@ -135,10 +135,21 @@ expand_d_format (const char *format)
 static char *
 escape_d_format (const char *format)
 {
+  bool quoted = false;
+  size_t format_len = 0;
   obstack buf;
 
   gcc_obstack_init (&buf);
 
+  /* If the format string is enclosed by two '`' characters, then don't escape
+     the first and last characters.  */
+  if (*format == '`')
+    {
+      format_len = strlen (format) - 1;
+      if (format_len && format[format_len] == '`')
+       quoted = true;
+    }
+
   for (const char *p = format; *p; p++)
     {
       switch (*p)
@@ -152,7 +163,8 @@ escape_d_format (const char *format)
        case '`':
          /* Escape '`' characters so that expand_d_format does not confuse them
             for a quoted string.  */
-         obstack_1grow (&buf, '\\');
+         if (!quoted || (p != format && p != (format + format_len)))
+           obstack_1grow (&buf, '\\');
          break;
 
        default:
-- 
2.30.2