[PATCH] lto: testsuite: Fix incr-link tests on wrapped targets

Hello-

This patch was discussed here:
https://gcc.gnu.org/pipermail/gcc-patches/2026-August/726564.html

I thought I should resend it since it was buried in that thread.

It was tested by me on x86-64 (with and without a target board enabling the
test glue wrapper), and by Torbjörn on arm-none-eabi where the issue was
first noticed. Is it OK please? Thanks!

-Lewis

-- >8 --

For targets that use a gluefile wrapper object, the extra object should not
be included in the link for the new LTO incr-link mode.

gcc/testsuite/ChangeLog:

	* lib/lto.exp (lto-link-and-maybe-run): Unset gluefile for the
	incremental link step, since the wrapper is not needed there and
	does not contain LTO sections.
---
 gcc/testsuite/lib/lto.exp | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/gcc/testsuite/lib/lto.exp b/gcc/testsuite/lib/lto.exp
index 7243547a52d..a6532e22076 100644
--- a/gcc/testsuite/lib/lto.exp
+++ b/gcc/testsuite/lib/lto.exp
@@ -375,6 +375,7 @@ proc lto-link-and-maybe-run { testname objlist dest optall optfile optstr } {
     global tool
     global compile_type
     global board_info
+    global gluefile
 
     upvar dg-messages-by-file dg-messages-by-file
 
@@ -408,16 +409,28 @@ proc lto-link-and-maybe-run { testname objlist dest optall optfile optstr } {
 	set board_info($target_board,ldscript) ""
     }
 
+    set is_incr_link [string equal "incr-link" $optstr]
+    if { $is_incr_link && [info exists gluefile] } {
+	set sav_gluefile $gluefile
+	# Setting gluefile to an empty string arranges that we still pass the needed
+	# -wrap flags to the linker, but we don't include the object file.
+	set gluefile ""
+    }
+
     # Link the objects into an executable.
     set comp_output [${tool}_target_compile "$objlist" $dest executable \
 		     "$options"]
 
+    if { [info exists sav_gluefile] } {
+	set gluefile $sav_gluefile
+    }
+
     if { $relocatable } {
 	set board_info($target_board,ldscript) $saved_ldscript
     }
 
     # Check for diagnostics specified by directives
-    if { ! [string equal "incr-link" $optstr] } {
+    if { ! $is_incr_link } {
 	set comp_output [lto_handle_diagnostics $comp_output $optstr]
     }