[Mesa-dev] [PATCH v2 2/5] mesa/util: add allow_glsl_builtin_const_expression driconf override

[Timothy Arceri]

Google Earth VR shaders uses builtins in constant expressions with
GLSL 1.10. That feature wasn't allowed until GLSL 1.20.
---
 src/compiler/glsl/ast_function.cpp                  | 3 ++-
 src/gallium/auxiliary/pipe-loader/driinfo_gallium.h | 1 +
 src/gallium/include/state_tracker/st_api.h          | 1 +
 src/gallium/state_trackers/dri/dri_screen.c         | 2 ++
 src/mesa/main/mtypes.h                              | 6 ++++++
 src/mesa/state_tracker/st_extensions.c              | 3 +++
 src/util/xmlpool/t_options.h                        | 5 +++++
 7 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/src/compiler/glsl/ast_function.cpp b/src/compiler/glsl/ast_function.cpp
index 22d58e48c64..127aa1f91c4 100644
--- a/src/compiler/glsl/ast_function.cpp
+++ b/src/compiler/glsl/ast_function.cpp
@@ -529,7 +529,8 @@ generate_call(exec_list *instructions, ir_function_signature *sig,
     * If the function call is a constant expression, don't generate any
     * instructions; just generate an ir_constant.
     */
-   if (state->is_version(120, 100)) {
+   if (state->is_version(120, 100) ||
+       state->ctx->Const.AllowGLSLBuiltinConstantExpression) {
       ir_constant *value = sig->constant_expression_value(ctx,
                                                           actual_parameters,
                                                           NULL);
diff --git a/src/gallium/auxiliary/pipe-loader/driinfo_gallium.h b/src/gallium/auxiliary/pipe-loader/driinfo_gallium.h
index 21dc599dc26..f25f2080080 100644
--- a/src/gallium/auxiliary/pipe-loader/driinfo_gallium.h
+++ b/src/gallium/auxiliary/pipe-loader/driinfo_gallium.h
@@ -23,6 +23,7 @@ DRI_CONF_SECTION_DEBUG
    DRI_CONF_DISABLE_SHADER_BIT_ENCODING("false")
    DRI_CONF_FORCE_GLSL_VERSION(0)
    DRI_CONF_ALLOW_GLSL_EXTENSION_DIRECTIVE_MIDSHADER("false")
+   DRI_CONF_ALLOW_GLSL_BUILTIN_CONST_EXPRESSION("false")
    DRI_CONF_ALLOW_GLSL_BUILTIN_VARIABLE_REDECLARATION("false")
    DRI_CONF_ALLOW_GLSL_CROSS_STAGE_INTERPOLATION_MISMATCH("false")
    DRI_CONF_ALLOW_HIGHER_COMPAT_VERSION("false")
diff --git a/src/gallium/include/state_tracker/st_api.h b/src/gallium/include/state_tracker/st_api.h
index ec6e7844b87..1efc7f081d1 100644
--- a/src/gallium/include/state_tracker/st_api.h
+++ b/src/gallium/include/state_tracker/st_api.h
@@ -222,6 +222,7 @@ struct st_config_options
    boolean force_glsl_extensions_warn;
    unsigned force_glsl_version;
    boolean allow_glsl_extension_directive_midshader;
+   boolean allow_glsl_builtin_const_expression;
    boolean allow_glsl_builtin_variable_redeclaration;
    boolean allow_higher_compat_version;
    boolean glsl_zero_init;
diff --git a/src/gallium/state_trackers/dri/dri_screen.c b/src/gallium/state_trackers/dri/dri_screen.c
index aaee9870776..a86b7519364 100644
--- a/src/gallium/state_trackers/dri/dri_screen.c
+++ b/src/gallium/state_trackers/dri/dri_screen.c
@@ -74,6 +74,8 @@ dri_fill_st_options(struct dri_screen *screen)
       driQueryOptioni(optionCache, "force_glsl_version");
    options->allow_glsl_extension_directive_midshader =
       driQueryOptionb(optionCache, "allow_glsl_extension_directive_midshader");
+   options->allow_glsl_builtin_const_expression =
+      driQueryOptionb(optionCache, "allow_glsl_builtin_const_expression");
    options->allow_glsl_builtin_variable_redeclaration =
       driQueryOptionb(optionCache, "allow_glsl_builtin_variable_redeclaration");
    options->allow_higher_compat_version =
diff --git a/src/mesa/main/mtypes.h b/src/mesa/main/mtypes.h
index 482c42a4b2d..41ad783d4b1 100644
--- a/src/mesa/main/mtypes.h
+++ b/src/mesa/main/mtypes.h
@@ -3716,6 +3716,12 @@ struct gl_constants
     */
    GLboolean AllowGLSLExtensionDirectiveMidShader;
 
+   /**
+    * Allow builtins as part of constant expressions. This was not allowed
+    * until GLSL 1.20 this allows it everywhere.
+    */
+   GLboolean AllowGLSLBuiltinConstantExpression;
+
    /**
     * Allow GLSL built-in variables to be redeclared verbatim
     */
diff --git a/src/mesa/state_tracker/st_extensions.c b/src/mesa/state_tracker/st_extensions.c
index 467d9b07596..7f44b4a80c0 100644
--- a/src/mesa/state_tracker/st_extensions.c
+++ b/src/mesa/state_tracker/st_extensions.c
@@ -1133,6 +1133,9 @@ void st_init_extensions(struct pipe_screen *screen,
    if (options->allow_glsl_extension_directive_midshader)
       consts->AllowGLSLExtensionDirectiveMidShader = GL_TRUE;
 
+   if (options->allow_glsl_builtin_const_expression)
+      consts->AllowGLSLBuiltinConstantExpression = GL_TRUE;
+
    consts->MinMapBufferAlignment =
       screen->get_param(screen, PIPE_CAP_MIN_MAP_BUFFER_ALIGNMENT);
 
diff --git a/src/util/xmlpool/t_options.h b/src/util/xmlpool/t_options.h
index 3ada813d639..1a4945d6888 100644
--- a/src/util/xmlpool/t_options.h
+++ b/src/util/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_CONST_EXPRESSION(def) \
+DRI_CONF_OPT_BEGIN_B(allow_glsl_builtin_const_expression, def) \
+        DRI_CONF_DESC(en,gettext("Allow builtins as part of constant expressions")) \
+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")) \
-- 
2.17.1