From a4306450589a730ee76367b3bc7d6b8c532c7b00 Mon Sep 17 00:00:00 2001
From: Alexander Medvednikov <alexander@medvednikov.com>
Date: Thu, 26 Feb 2026 08:38:27 +0300
Subject: [PATCH] builder: fix dynamic library loading and cc improvements
 (fixes #16899)

---
 examples/dynamic_library_loading/use_library_test.v | 10 ++++++++++
 vlib/v/builder/cc.v                                 | 12 ++++++++++++
 2 files changed, 22 insertions(+)

diff --git a/examples/dynamic_library_loading/use_library_test.v b/examples/dynamic_library_loading/use_library_test.v
index a760beb2a..73fb2ebd5 100644
--- a/examples/dynamic_library_loading/use_library_test.v
+++ b/examples/dynamic_library_loading/use_library_test.v
@@ -45,6 +45,16 @@ fn test_can_compile_and_use_library_with_skip_unused() {
 	os.rm(library_file_name) or {}
 }
 
+fn test_can_compile_and_use_library_with_prod() {
+	os.chdir(cfolder) or {}
+	os.rm(library_file_name) or {}
+	v_compile('-prod -d no_backtrace -o library -shared modules/library/library.v')
+	assert os.is_file(library_file_name)
+	result := v_compile('run use_dl_module.v')
+	assert result.output.contains('res: 4')
+	os.rm(library_file_name) or {}
+}
+
 fn v_compile(vopts string) os.Result {
 	cmd := '${os.quoted_path(vexe)} -showcc ${vopts}'
 	// dump(cmd)
diff --git a/vlib/v/builder/cc.v b/vlib/v/builder/cc.v
index 12c5815c9..6d0c55e35 100644
--- a/vlib/v/builder/cc.v
+++ b/vlib/v/builder/cc.v
@@ -256,6 +256,10 @@ fn (mut v Builder) setup_ccompiler_options(ccompiler string) {
 		if v.pref.parallel_cc {
 			have_flto = false
 		}
+		if v.pref.is_shared {
+			// Keep shared libraries away from LTO to avoid runtime loader regressions.
+			have_flto = false
+		}
 		if have_flto {
 			optimization_options << '-flto'
 		}
@@ -278,6 +282,10 @@ fn (mut v Builder) setup_ccompiler_options(ccompiler string) {
 		if v.pref.parallel_cc {
 			have_flto = false
 		}
+		if v.pref.is_shared {
+			// Keep shared libraries away from LTO to avoid runtime loader regressions.
+			have_flto = false
+		}
 		if have_flto {
 			optimization_options << '-flto'
 		}
@@ -1101,6 +1109,10 @@ fn (mut c Builder) cc_windows_cross() {
 			if c.pref.parallel_cc {
 				have_flto = false
 			}
+			if c.pref.is_shared {
+				// Keep shared libraries away from LTO to avoid runtime loader regressions.
+				have_flto = false
+			}
 			if have_flto {
 				optimization_options << '-flto'
 			}
-- 
2.39.5