glsl: Move is_builtin flag back to ir_function_signature.

This effectively reverts b6f15869b324ae64a00d0fe46fa3c8c62c1edb6c.

In desktop GLSL, defining a function with the same name as a built-in
hides that built-in function completely, so there would never be
built-in and user function signatures in the same ir_function.

However, in GLSL ES, overloading built-ins is allowed, and does not
hide the built-in signatures - so we're back to needing this.

1 files changed, 5 insertions, 2 deletions

diff --git a/src/glsl/ir.h b/src/glsl/ir.h
index efe59d8064..0d933024df 100644
--- a/src/glsl/ir.h
+++ b/src/glsl/ir.h
@@ -342,6 +342,9 @@ public:
    /** Whether or not this function has a body (which may be empty). */
    unsigned is_defined:1;
 
+   /** Whether or not this function signature is a built-in. */
+   unsigned is_builtin:1;
+
    /** Body of instructions in the function. */
    struct exec_list body;
 
@@ -407,8 +410,8 @@ public:
     */
    const char *name;
 
-   /** Whether or not this function is a built-in. */
-   unsigned is_builtin:1;
+   /** Whether or not this function has a signature that is a built-in. */
+   bool has_builtin_signature();
 
    /**
     * List of ir_function_signature for each overloaded function with this name.