From: Akihiro Sagawa <sagawa.aki@gmail.com>
Subject: [PATCH] winex11.drv: Mask floating-point invalid exception during glXCreateContext().
Message-Id: <20210408232258.E982.375B48EC@gmail.com>
Date: Thu, 08 Apr 2021 23:25:15 +0900


Workaround for Mesa bug 3096.
I can reproduce the issue with Mesa 21.2 and set LIBGL_ALWAYS_SOFTWARE
environment to 1, i.e. LIBGL_ALWAYS_SOFTWARE=1.

Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=47716
Signed-off-by: Akihiro Sagawa <sagawa.aki@gmail.com>
---
 configure.ac              |  2 ++
 dlls/winex11.drv/opengl.c | 40 +++++++++++++++++++++++++++++++++++++++
 2 files changed, 42 insertions(+)

diff --git a/configure.ac b/configure.ac
index 2f5a6987a13..a2344680224 100644
--- a/configure.ac
+++ b/configure.ac
@@ -448,6 +448,7 @@ AC_CHECK_HEADERS(\
 	dirent.h \
 	dlfcn.h \
 	elf.h \
+	fenv.h \
 	float.h \
 	fnmatch.h \
 	getopt.h \
@@ -2673,6 +2674,7 @@ AC_CHECK_FUNCS(\
 	exp2f \
 	expm1 \
 	expm1f \
+	fedisableexcept \
 	fma \
 	fmaf \
 	j0 \
diff --git a/dlls/winex11.drv/opengl.c b/dlls/winex11.drv/opengl.c
index c44c587bf14..a611c7f11ea 100644
--- a/dlls/winex11.drv/opengl.c
+++ b/dlls/winex11.drv/opengl.c
@@ -36,6 +36,9 @@
 #ifdef HAVE_SYS_UN_H
 #include <sys/un.h>
 #endif
+#ifdef HAVE_FENV_H
+#include <fenv.h>
+#endif
 
 #include "x11drv.h"
 #include "xcomposite.h"
@@ -259,6 +262,15 @@ enum glx_swap_control_method
     GLX_SWAP_CONTROL_MESA
 };
 
+/* floating-point environments, see save_fenv() for details */
+struct fenv
+{
+    int old_excepts;
+#ifdef HAVE_FENV_H
+    fenv_t fenv;
+#endif
+};
+
 /* X context to associate a struct gl_drawable to an hwnd */
 static XContext gl_hwnd_context;
 /* X context to associate a struct gl_drawable to a pbuffer hdc */
@@ -417,6 +429,26 @@ static int GLXErrorHandler(Display *dpy, XErrorEvent *event, void *arg)
     return 1;
 }
 
+/* Workaround for Mesa 20.1's NaN to integer operation
+   when FE_INVALID is unmasked and llvmpipe is used. */
+static inline void save_fenv(struct fenv *fenv)
+{
+#if defined(HAVE_FEDISABLEEXCEPT) && defined(FE_INVALID)
+    if (fegetenv(&fenv->fenv) == 0)
+        fenv->old_excepts = fedisableexcept(FE_INVALID);
+    else
+        fenv->old_excepts = -1;
+#endif
+}
+
+static inline void restore_fenv(const struct fenv *fenv)
+{
+#if defined(HAVE_FEDISABLEEXCEPT) && defined(FE_INVALID)
+    if (fenv->old_excepts != -1 && (fenv->old_excepts & FE_INVALID))
+        fesetenv(&fenv->fenv);
+#endif
+}
+
 static BOOL X11DRV_WineGL_InitOpenglInfo(void)
 {
     static const char legacy_extensions[] = " WGL_EXT_extensions_string WGL_EXT_swap_control";
@@ -441,6 +473,10 @@ static BOOL X11DRV_WineGL_InitOpenglInfo(void)
     if (vis) {
 #ifdef __i386__
         WORD old_fs, new_fs;
+#endif
+        struct fenv fenv;
+        save_fenv(&fenv);
+#ifdef __i386__
         __asm__( "mov %%fs,%0" : "=r" (old_fs) );
         /* Create a GLX Context. Without one we can't query GL information */
         ctx = pglXCreateContext(gdi_display, vis, None, GL_TRUE);
@@ -455,6 +491,7 @@ static BOOL X11DRV_WineGL_InitOpenglInfo(void)
 #else
         ctx = pglXCreateContext(gdi_display, vis, None, GL_TRUE);
 #endif
+        restore_fenv(&fenv);
     }
     if (!ctx) goto done;
 
@@ -1286,7 +1323,9 @@ static struct gl_drawable *get_gl_drawable( HWND hwnd, HDC hdc )
 static GLXContext create_glxcontext(Display *display, struct wgl_context *context, GLXContext shareList)
 {
     GLXContext ctx;
+    struct fenv fenv;
 
+    save_fenv(&fenv);
     if(context->gl3_context)
     {
         if(context->numAttribs)
@@ -1299,6 +1338,7 @@ static GLXContext create_glxcontext(Display *display, struct wgl_context *contex
     else /* Create a GLX Context for a pbuffer */
         ctx = pglXCreateNewContext(gdi_display, context->fmt->fbconfig, context->fmt->render_type, shareList, TRUE);
 
+    restore_fenv(&fenv);
     return ctx;
 }