[PATCH v6 1/7] tools: helper functions for LTO builds

[Konstantin Demin]

From: Konstantin Demin

Signed-off-by: Konstantin Demin 
---
 tools/lto.h | 132 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 132 insertions(+)
 create mode 100644 tools/lto.h

diff --git a/tools/lto.h b/tools/lto.h
new file mode 100644
index 00000000000..64fc62e49fe
--- /dev/null
+++ b/tools/lto.h
@@ -0,0 +1,132 @@
+/*
+ * LTO helper functions for the Wine tools
+ *
+ * Copyright 2025 Konstantin Demin
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
+ */
+
+#ifndef __WINE_LTO_H
+#define __WINE_LTO_H
+
+#ifndef __WINE_TOOLS_H
+# error You must include tools.h to use this header
+#endif
+
+
+__attribute__((used))
+static void append_lto_flags( struct strarray *args, int with_lto, int prefer_env )
+{
+    if (with_lto < 0) return;
+
+    if (prefer_env > 0)
+    {
+        const char *flags;
+
+        if (with_lto > 0)
+        {
+            static int init_lto = 0;
+            static const char* flags_lto;
+
+            if (!init_lto)
+            {
+                flags_lto = getenv( "WINE_LTO_FLAGS" );
+                if (flags_lto) flags_lto = xstrdup( flags_lto );
+                init_lto = 1;
+            }
+            flags = flags_lto;
+        }
+        else
+        {
+            static int init_lto_skip = 0;
+            static const char* flags_lto_skip;
+
+            if (!init_lto_skip)
+            {
+                flags_lto_skip = getenv( "WINE_LTO_SKIP_FLAGS" );
+                if (flags_lto_skip) flags_lto_skip = xstrdup( flags_lto_skip );
+                init_lto_skip = 1;
+            }
+            flags = flags_lto_skip;
+        }
+
+        if (flags) {
+            strarray_addall( args, strarray_fromstring( flags, " " ) );
+            return;
+        }
+    }
+
+    strarray_add( args, (with_lto > 0) ? "-flto" : "-fno-lto" );
+}
+
+
+static int var_to_bool( const char *var )
+{
+    if (!var) return 0;
+    if (!( var[0] )) return 0;
+
+    switch (var[0])
+    {
+        /* "1" */
+        case '1':
+            if (!var[1]) return 1;
+            break;
+
+        /* "[Tt]", "[Tt][Rr][Uu][Ee]" */
+        case 'T': /* -fallthrough */
+        case 't':
+            if (!var[1]) return 1;
+
+            if (strlen( var ) != 4) break;
+            if ((var[1] != 'R') && (var[1] != 'r')) break;
+            if ((var[2] != 'U') && (var[2] != 'u')) break;
+            if ((var[3] != 'E') && (var[3] != 'e')) break;
+            return 1;
+
+            break;
+
+        /* "[Yy]", "[Yy][Ee][Ss]" */
+        case 'Y': /* -fallthrough */
+        case 'y':
+            if (!var[1]) return 1;
+
+            if (strlen( var ) != 3) break;
+            if ((var[1] != 'E') && (var[1] != 'e')) break;
+            if ((var[2] != 'S') && (var[2] != 's')) break;
+            return 1;
+
+            break;
+    }
+
+    return 0;
+}
+
+
+__attribute__((used))
+static int adjust_verbose_lto( int with_lto, int verbose )
+{
+    const char* lto_debug;
+
+    if (with_lto < 1) return verbose;
+    if (verbose > 0) return verbose;
+
+    lto_debug = getenv( "WINE_LTO_DEBUG" );
+    if (!lto_debug) return verbose;
+
+    return var_to_bool( lto_debug );
+}
+
+
+#endif /* __WINE_LTO_H */