driconf: Add allow_glsl_builtin_variable_redeclaration option

This option will allow GLSL builtins to be redeclared verbatim (e.g.
redeclaring "in int gl_VertexID" in a vertex shader). This is not strictly
valid and would normally fail to compile, but some applications (such as
newer Techland ports) do it and need more leniency.

v2 (Samuel Pitoiset):
    - Rename allow_glsl_builtin_redeclaration ->
      allow_glsl_builtin_variable_redeclaration

Signed-off-by: John Brooks <[email protected]>
Reviewed-by: Edward O'Callaghan <[email protected]>
Reviewed-by: Samuel Pitoiset <[email protected]>

5 files changed, 16 insertions, 0 deletions

diff --git a/src/mesa/drivers/dri/common/xmlpool/t_options.h b/src/mesa/drivers/dri/common/xmlpool/t_options.h
index cd4f0252b92..ec0f3f7eaca 100644
--- a/src/mesa/drivers/dri/common/xmlpool/t_options.h
+++ b/src/mesa/drivers/dri/common/xmlpool/t_options.h
@@ -115,6 +115,11 @@ DRI_CONF_OPT_BEGIN_B(allow_glsl_extension_directive_midshader, def) \
         DRI_CONF_DESC(en,gettext("Allow GLSL #extension directives in the middle of shaders")) \
 DRI_CONF_OPT_END
 
+#define DRI_CONF_ALLOW_GLSL_BUILTIN_VARIABLE_REDECLARATION(def) \
+DRI_CONF_OPT_BEGIN_B(allow_glsl_builtin_variable_redeclaration, def) \
+        DRI_CONF_DESC(en,gettext("Allow GLSL built-in variables to be redeclared verbatim")) \
+DRI_CONF_OPT_END
+
 #define DRI_CONF_ALLOW_HIGHER_COMPAT_VERSION(def) \
 DRI_CONF_OPT_BEGIN_B(allow_higher_compat_version, def) \
         DRI_CONF_DESC(en,gettext("Allow a higher compat profile (version 3.1+) for apps that request it")) \
diff --git a/src/mesa/drivers/dri/i965/brw_context.c b/src/mesa/drivers/dri/i965/brw_context.c
index 5055dd76a84..d3ed871618c 100644
--- a/src/mesa/drivers/dri/i965/brw_context.c
+++ b/src/mesa/drivers/dri/i965/brw_context.c
@@ -934,6 +934,9 @@ brw_process_driconf_options(struct brw_context *brw)
    ctx->Const.AllowGLSLExtensionDirectiveMidShader =
       driQueryOptionb(options, "allow_glsl_extension_directive_midshader");
 
+   ctx->Const.AllowGLSLBuiltinVariableRedeclaration =
+      driQueryOptionb(options, "allow_glsl_builtin_variable_redeclaration");
+
    ctx->Const.AllowHigherCompatVersion =
       driQueryOptionb(options, "allow_higher_compat_version");
 
diff --git a/src/mesa/drivers/dri/i965/intel_screen.c b/src/mesa/drivers/dri/i965/intel_screen.c
index 91ed128f832..9842de67423 100644
--- a/src/mesa/drivers/dri/i965/intel_screen.c
+++ b/src/mesa/drivers/dri/i965/intel_screen.c
@@ -89,6 +89,7 @@ DRI_CONF_BEGIN
       DRI_CONF_DISABLE_BLEND_FUNC_EXTENDED("false")
       DRI_CONF_DUAL_COLOR_BLEND_BY_LOCATION("false")
       DRI_CONF_ALLOW_GLSL_EXTENSION_DIRECTIVE_MIDSHADER("false")
+      DRI_CONF_ALLOW_GLSL_BUILTIN_VARIABLE_REDECLARATION("false")
       DRI_CONF_ALLOW_HIGHER_COMPAT_VERSION("false")
       DRI_CONF_FORCE_GLSL_ABS_SQRT("false")
 
diff --git a/src/mesa/main/mtypes.h b/src/mesa/main/mtypes.h
index d47c428936c..7ac0ee36778 100644
--- a/src/mesa/main/mtypes.h
+++ b/src/mesa/main/mtypes.h
@@ -3638,6 +3638,11 @@ struct gl_constants
    GLboolean AllowGLSLExtensionDirectiveMidShader;
 
    /**
+    * Allow GLSL built-in variables to be redeclared verbatim
+    */
+   GLboolean AllowGLSLBuiltinVariableRedeclaration;
+
+   /**
     * Allow creating a higher compat profile (version 3.1+) for apps that
     * request it. Be careful when adding that driconf option because some
     * features are unimplemented and might not work correctly.
diff --git a/src/mesa/state_tracker/st_extensions.c b/src/mesa/state_tracker/st_extensions.c
index 2fa7ba7797e..a8cd2b4e174 100644
--- a/src/mesa/state_tracker/st_extensions.c
+++ b/src/mesa/state_tracker/st_extensions.c
@@ -892,6 +892,8 @@ void st_init_extensions(struct pipe_screen *screen,
 
    consts->ForceGLSLAbsSqrt = options->force_glsl_abs_sqrt;
 
+   consts->AllowGLSLBuiltinVariableRedeclaration = options->allow_glsl_builtin_variable_redeclaration;
+
    consts->dri_config_options_sha1 = options->config_options_sha1;
 
    if (consts->GLSLVersion >= 400)