mesa: refuse to compile SPIR-V shaders or link mixed shaders

Note that gl_shader::CompileStatus will also indicate whether a shader
has been successfully specialized.

v2: Use the 'spirv_data' member of gl_shader to know if it is a SPIR-V
   shader, instead of a dedicated flag. (Timothy Arceri)

v3: Use bool instead of GLboolean. (Ian Romanick)

Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>

src/mesa/main/shaderapi.c

@@ -1097,6 +1097,18 @@ _mesa_compile_shader(struct gl_context *ctx, struct gl_shader *sh)
    if (!sh)
       return;
 
+   /* The GL_ARB_gl_spirv spec says:
+    *
+    *    "Add a new error for the CompileShader command:
+    *
+    *      An INVALID_OPERATION error is generated if the SPIR_V_BINARY_ARB
+    *      state of <shader> is TRUE."
+    */
+   if (sh->spirv_data) {
+      _mesa_error(ctx, GL_INVALID_OPERATION, "glCompileShader(SPIR-V)");
+      return;
+   }
+
    if (!sh->Source) {
       /* If the user called glCompileShader without first calling
        * glShaderSource, we should fail to compile, but not raise a GL_ERROR.

src/mesa/program/ir_to_mesa.cpp

@@ -3083,6 +3083,7 @@ void
 _mesa_glsl_link_shader(struct gl_context *ctx, struct gl_shader_program *prog)
 {
    unsigned int i;
+   bool spirv;
 
    _mesa_clear_shader_program_data(ctx, prog);
 
@@ -3092,7 +3093,21 @@ _mesa_glsl_link_shader(struct gl_context *ctx, struct gl_shader_program *prog)
 
    for (i = 0; i < prog->NumShaders; i++) {
       if (!prog->Shaders[i]->CompileStatus) {
-	 linker_error(prog, "linking with uncompiled shader");
+	 linker_error(prog, "linking with uncompiled/unspecialized shader");
+      }
+
+      if (!i) {
+         spirv = (prog->Shaders[i]->spirv_data != NULL);
+      } else if (spirv && !prog->Shaders[i]->spirv_data) {
+         /* The GL_ARB_gl_spirv spec adds a new bullet point to the list of
+          * reasons LinkProgram can fail:
+          *
+          *    "All the shader objects attached to <program> do not have the
+          *     same value for the SPIR_V_BINARY_ARB state."
+          */
+         linker_error(prog,
+                      "not all attached shaders have the same "
+                      "SPIR_V_BINARY_ARB state");
       }
    }