[binutils-gdb] Allow styling when using throw_* functions

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=54c605be19b266001c0fcd19ea4c916d74759927

commit 54c605be19b266001c0fcd19ea4c916d74759927
Author: Tom Tromey <[email protected]>
Date:   Tue Apr 7 18:18:40 2026 -0600

    Allow styling when using throw_* functions
    
    The throw_* family of functions use the varargs constructor for
    gdb_exception, which then calls string_vprintf.  This means that
    styling cannot be applied here by gdb.
    
    This patch changes this code to use a client-supplied formatting
    function.  For gdbserver this remains string_vprintf, but for gdb it
    now allows styling.
    
    I did look at unifying 'error' and the throw_* functions a bit more,
    but this would have meant unravelling some IPA code.

Diff:
---
 gdb/utils.c                    | 10 ++++++++++
 gdbserver/utils.cc             | 12 ++++++++++++
 gdbsupport/common-exceptions.h |  7 ++++++-
 3 files changed, 28 insertions(+), 1 deletion(-)

diff --git a/gdb/utils.c b/gdb/utils.c
index a7e91ce686b..4f99cdb425b 100644
--- a/gdb/utils.c
+++ b/gdb/utils.c
@@ -182,6 +182,16 @@ vwarning (const char *string, va_list args)
     }
 }
 
+/* See common-exceptions.h.  */
+
+std::string
+vformat_exception (const char *fmt, va_list args)
+{
+  string_file text (true);
+  text.vprintf (fmt, args);
+  return text.release ();
+}
+
 /* Print an error message and return to command level.
    The first argument STRING is the error message, used as a fprintf string,
    and the remaining args are passed as arguments to it.  */
diff --git a/gdbserver/utils.cc b/gdbserver/utils.cc
index 9bc3fc4477e..468e803e34d 100644
--- a/gdbserver/utils.cc
+++ b/gdbserver/utils.cc
@@ -104,3 +104,15 @@ paddress (CORE_ADDR addr)
 {
   return phex_nz (addr);
 }
+
+#ifndef IN_PROCESS_AGENT
+
+/* See common-exceptions.h.  */
+
+std::string
+vformat_exception (const char *fmt, va_list args)
+{
+  return string_vprintf (fmt, args);
+}
+
+#endif /* IN_PROCESS_AGENT */
diff --git a/gdbsupport/common-exceptions.h b/gdbsupport/common-exceptions.h
index 5a50ff44c31..1f3bc84216e 100644
--- a/gdbsupport/common-exceptions.h
+++ b/gdbsupport/common-exceptions.h
@@ -116,6 +116,11 @@ enum errors {
   NR_ERRORS
 };
 
+/* The client application must provide this.  It is a printf-like that
+   formats a string for an exception.  */
+std::string vformat_exception (const char *fmt, va_list args)
+  ATTRIBUTE_PRINTF (1, 0);
+
 struct gdb_exception
 {
   gdb_exception ()
@@ -142,7 +147,7 @@ struct gdb_exception
     ATTRIBUTE_PRINTF (4, 0)
     : reason (r),
       error (e),
-      message (std::make_shared<std::string> (string_vprintf (fmt, ap)))
+      message (std::make_shared<std::string> (vformat_exception (fmt, ap)))
   {
   }