glsl: add a mechanism to allow #extension directives in the middle of shaders

This is needed to make Unigine Heaven 4.0 and Unigine Valley 1.0 work
with sample shading.

Also, if this is disabled, the error message at least makes sense now.

Reviewed-by: Brian Paul <[email protected]>
Reviewed-by: Kenneth Graunke <[email protected]>
Reviewed-by: Ian Romanick <[email protected]>

4 files changed, 17 insertions, 0 deletions

diff --git a/src/glsl/glsl_parser.yy b/src/glsl/glsl_parser.yy
index b9897498ff7..4c871633f0e 100644
--- a/src/glsl/glsl_parser.yy
+++ b/src/glsl/glsl_parser.yy
@@ -376,6 +376,14 @@ external_declaration_list:
       if ($2 != NULL)
          state->translation_unit.push_tail(& $2->link);
    }
+   | external_declaration_list extension_statement {
+      if (!state->allow_extension_directive_midshader) {
+         _mesa_glsl_error(& @2, state,
+                          "#extension directive is not allowed "
+                          "in the middle of a shader");
+         YYERROR;
+      }
+   }
    ;
 
 variable_identifier:
diff --git a/src/glsl/glsl_parser_extras.cpp b/src/glsl/glsl_parser_extras.cpp
index b327c2b4319..890123ad1cf 100644
--- a/src/glsl/glsl_parser_extras.cpp
+++ b/src/glsl/glsl_parser_extras.cpp
@@ -210,6 +210,8 @@ _mesa_glsl_parse_state::_mesa_glsl_parse_state(struct gl_context *_ctx,
    this->early_fragment_tests = false;
    memset(this->atomic_counter_offsets, 0,
           sizeof(this->atomic_counter_offsets));
+   this->allow_extension_directive_midshader =
+      ctx->Const.AllowGLSLExtensionDirectiveMidShader;
 }
 
 /**
diff --git a/src/glsl/glsl_parser_extras.h b/src/glsl/glsl_parser_extras.h
index 6df41d442de..ce66e2fa45b 100644
--- a/src/glsl/glsl_parser_extras.h
+++ b/src/glsl/glsl_parser_extras.h
@@ -493,6 +493,8 @@ struct _mesa_glsl_parse_state {
 
    /** Atomic counter offsets by binding */
    unsigned atomic_counter_offsets[MAX_COMBINED_ATOMIC_BUFFERS];
+
+   bool allow_extension_directive_midshader;
 };
 
 # define YYLLOC_DEFAULT(Current, Rhs, N)			\
diff --git a/src/mesa/main/mtypes.h b/src/mesa/main/mtypes.h
index b699021adbd..91d9172f9c1 100644
--- a/src/mesa/main/mtypes.h
+++ b/src/mesa/main/mtypes.h
@@ -3363,6 +3363,11 @@ struct gl_constants
    GLuint ForceGLSLVersion;
 
    /**
+    * Allow GLSL #extension directives in the middle of shaders.
+    */
+   GLboolean AllowGLSLExtensionDirectiveMidShader;
+
+   /**
     * Does the driver support real 32-bit integers?  (Otherwise, integers are
     * simulated via floats.)
     */