From cea946e39d62b95139b2d16520bf7b9b509d5fbc Mon Sep 17 00:00:00 2001 From: Paul Berry Date: Wed, 31 Jul 2013 11:25:13 -0700 Subject: glsl: In ir_set_program_inouts, handle indexing outside array/matrix bounds. According to GLSL, indexing into an array or matrix with an out-of-range constant results in a compile error. However, indexing with an out-of-range value that isn't constant merely results in undefined results. Since optimization passes (e.g. loop unrolling) can convert non-constant array indices into constant array indices, it's possible that ir_set_program_inouts will encounter a constant array index that is out of range; if this happens, just mark the whole array as used. Reviewed-by: Ian Romanick Reviewed-by: Kenneth Graunke --- src/glsl/ir_set_program_inouts.cpp | 31 ++++++++++++++++++++++++++----- 1 file changed, 26 insertions(+), 5 deletions(-) (limited to 'src/glsl') diff --git a/src/glsl/ir_set_program_inouts.cpp b/src/glsl/ir_set_program_inouts.cpp index ea55447..27c3ca7 100644 --- a/src/glsl/ir_set_program_inouts.cpp +++ b/src/glsl/ir_set_program_inouts.cpp @@ -171,13 +171,34 @@ ir_set_program_inouts_visitor::try_mark_partial_variable(ir_variable *var, if (!index_as_constant) return false; - int width = 1; - if (type->is_array() && type->fields.array->is_matrix()) { - width = type->fields.array->matrix_columns; + unsigned elem_width; + unsigned num_elems; + if (type->is_array()) { + num_elems = type->length; + if (type->fields.array->is_matrix()) + elem_width = type->fields.array->matrix_columns; + else + elem_width = 1; + } else { + num_elems = type->matrix_columns; + elem_width = 1; } - mark(this->prog, var, index_as_constant->value.u[0] * width, width, - this->shader_type == GL_FRAGMENT_SHADER); + if (index_as_constant->value.u[0] >= num_elems) { + /* Constant index outside the bounds of the matrix/array. This could + * arise as a result of constant folding of a legal GLSL program. + * + * Even though the spec says that indexing outside the bounds of a + * matrix/array results in undefined behaviour, we don't want to pass + * out-of-range values to mark() (since this could result in slots that + * don't exist being marked as used), so just let the caller mark the + * whole variable as used. + */ + return false; + } + + mark(this->prog, var, index_as_constant->value.u[0] * elem_width, + elem_width, this->shader_type == GL_FRAGMENT_SHADER); return true; } -- cgit v1.1