[diagnostics] Print invocation upon ICE

[Nathan Sidwell]

This patch augments the crash dumper to print the invocation (that we had 
handily stashed away). We also already have a convenient static var we use to 
detect recursion, and can repurpose for holding the argv array.

This has proven invaluable in investigating lto crashes I've encountered.
nathan
--
Nathan Sidwell
From 456f5b0f7855ee12774528246bd4364ef2c0fb3e Mon Sep 17 00:00:00 2001
From: Nathan Sidwell <nat...@acm.org>
Date: Sat, 1 Nov 2025 20:02:47 -0400
Subject: [PATCH] diagnostics: Print invokation on ICE

Print the compiler's invocation upon ICE. Particularly useful on LTO
crashes.

	gcc/
	* diagnostics/context.cc (context::action_after_output): Print
	invocation on ICE.
---
 gcc/diagnostics/context.cc | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/gcc/diagnostics/context.cc b/gcc/diagnostics/context.cc
index 2543a6031ec..2a767a68fe3 100644
--- a/gcc/diagnostics/context.cc
+++ b/gcc/diagnostics/context.cc
@@ -1003,10 +1003,11 @@ context::action_after_output (enum kind diag_kind)
 	/* Attempt to ensure that any outputs are flushed e.g. that .sarif
 	   files are written out.
 	   Only do it once.  */
-	static bool finishing_due_to_ice = false;
-	if (!finishing_due_to_ice)
+	static char **saved_argv = nullptr;
+	if (!saved_argv)
 	  {
-	    finishing_due_to_ice = true;
+	    saved_argv = m_original_argv;
+	    m_original_argv = nullptr;
 	    finish ();
 	  }
 
@@ -1021,6 +1022,12 @@ context::action_after_output (enum kind diag_kind)
 	if (m_abort_on_error)
 	  real_abort ();
 
+	bool space = false;
+	for (auto *argv = saved_argv; *argv; space = true)
+	  fnotice (stderr, &" %s"[1 - space], *argv++);
+	fnotice (stderr, "\n");
+	freeargv (saved_argv);
+
 	if (m_report_bug)
 	  fnotice (stderr, "Please submit a full bug report, "
 		   "with preprocessed source.\n");
-- 
2.51.1