glsl: clear out shader code before compiling

When we start compiling a shader, first free the existing gl_program.
This (mostly) fixes the piglit glsl-reload-source test.
Without this change, we were actually appending the new GPU code
onto the previous program.

diff --git a/src/mesa/shader/slang/slang_compile.c b/src/mesa/shader/slang/slang_compile.c
index c1b97c7cb708efdb2a7a8a4e7c8e5520469656f7..95c44e305474ae87e087d9dbdc0c177262b8a0ed 100644 (file)
--- a/src/mesa/shader/slang/slang_compile.c
+++ b/src/mesa/shader/slang/slang_compile.c
@@ -2738,6 +2738,7 @@ _slang_compile(GLcontext *ctx, struct gl_shader *shader)
    slang_info_log info_log;
    slang_code_object obj;
    slang_unit_type type;
+   GLenum progTarget;
 
    if (shader->Type == GL_VERTEX_SHADER) {
       type = SLANG_UNIT_VERTEX_SHADER;
@@ -2754,17 +2755,18 @@ _slang_compile(GLcontext *ctx, struct gl_shader *shader)
 
    shader->Main = GL_FALSE;
 
-   if (!shader->Program) {
-      GLenum progTarget;
-      if (shader->Type == GL_VERTEX_SHADER)
-         progTarget = GL_VERTEX_PROGRAM_ARB;
-      else
-         progTarget = GL_FRAGMENT_PROGRAM_ARB;
-      shader->Program = ctx->Driver.NewProgram(ctx, progTarget, 1);
-      shader->Program->Parameters = _mesa_new_parameter_list();
-      shader->Program->Varying = _mesa_new_parameter_list();
-      shader->Program->Attributes = _mesa_new_parameter_list();
-   }
+   /* free the shader's old instructions, etc */
+   _mesa_reference_program(ctx, &shader->Program, NULL);
+
+   /* allocate new GPU program, parameter lists, etc. */
+   if (shader->Type == GL_VERTEX_SHADER)
+      progTarget = GL_VERTEX_PROGRAM_ARB;
+   else
+      progTarget = GL_FRAGMENT_PROGRAM_ARB;
+   shader->Program = ctx->Driver.NewProgram(ctx, progTarget, 1);
+   shader->Program->Parameters = _mesa_new_parameter_list();
+   shader->Program->Varying = _mesa_new_parameter_list();
+   shader->Program->Attributes = _mesa_new_parameter_list();
 
    slang_info_log_construct(&info_log);
    _slang_code_object_ctr(&obj);