linker: Check that initializers for global variables match
This requires tracking a couple extra fields in ir_variable:
* A flag to indicate that a variable had an initializer.
* For non-const variables, a field to track the constant value of the
variable's initializer.
For variables non-constant initalizers, ir_variable::has_initializer
will be true, but ir_variable::constant_initializer will be NULL. The
linker can use the values of these fields to check adherence to the
GLSL 4.20 rules for shared global variables:
"If a shared global has multiple initializers, the initializers
must all be constant expressions, and they must all have the same
value. Otherwise, a link error will result. (A shared global
having only one initializer does not require that initializer to
be a constant expression.)"
Previous to 4.20 the GLSL spec simply said that initializers must have
the same value. In this case of non-constant initializers, this was
impossible to determine. As a result, no vendor actually implemented
that behavior. The 4.20 behavior matches the behavior of NVIDIA's
shipping implementations.
NOTE: This is candidate for the 7.11 branch. This patch also needs
the preceding patch "glsl: Refactor generate_ARB_draw_buffers_variables
to use add_builtin_constant"
Signed-off-by: Ian Romanick <ian.d.romanick@intel.com>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=34687
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Acked-by: Paul Berry <stereotype441@gmail.com>
diff --git a/src/glsl/ir_variable.cpp b/src/glsl/ir_variable.cpp
index 8fbcf1d..3092507 100644
--- a/src/glsl/ir_variable.cpp
+++ b/src/glsl/ir_variable.cpp
@@ -408,6 +408,8 @@
name, glsl_type::int_type,
ir_var_auto, -1);
var->constant_value = new(var) ir_constant(value);
+ var->constant_initializer = new(var) ir_constant(value);
+ var->has_initializer = true;
return var;
}