glsl: Switch ast_type_qualifier to a 128-bit bitset.

This should end the drought of bits in the ast_type_qualifier object.
The bitset_t type works pretty much as a drop-in replacement for the
current uint64_t bitset.

The only catch is that the bitset_t type as defined in the previous
commit doesn't have a trivial constructor (because it has a
user-defined constructor), so it cannot be used as union member
without providing a user-defined constructor for the union (which
causes it in turn to be non-trivially constructible).  This annoyance
could be easily addressed in C++11 by declaring the default
constructor of bitset_t to be the implicitly defined one -- IMO one
more reason to drop support for GCC 4.2-4.3.

The other minor change was required because glsl_parser_extras.cpp was
hard-coding the type of bitset temporaries as uint64_t, which (unlike
would have been the case if the uint64_t had been replaced with
e.g. an __int128) would otherwise have caused a build failure, because
the boolean conversion operator of bitset_t is marked explicit (if
C++11 is available), so the bitset won't be silently truncated down to
1 bit in order to use it to initialize the uint64_t temporaries
(yikes).

Reviewed-by: Plamena Manolova <[email protected]>

1 files changed, 6 insertions, 2 deletions

diff --git a/src/compiler/glsl/ast.h b/src/compiler/glsl/ast.h
index eee22482812..2a38a4b1f73 100644
--- a/src/compiler/glsl/ast.h
+++ b/src/compiler/glsl/ast.h
@@ -28,6 +28,7 @@
 #include "list.h"
 #include "glsl_parser_extras.h"
 #include "compiler/glsl_types.h"
+#include "util/bitset.h"
 
 struct _mesa_glsl_parse_state;
 
@@ -473,8 +474,11 @@ enum {
 
 struct ast_type_qualifier {
    DECLARE_RALLOC_CXX_OPERATORS(ast_type_qualifier);
+   DECLARE_BITSET_T(bitset_t, 128);
+
+   union flags {
+      flags() : i(0) {}
 
-   union {
       struct {
 	 unsigned invariant:1;
          unsigned precise:1;
@@ -636,7 +640,7 @@ struct ast_type_qualifier {
       q;
 
       /** \brief Set of flags, accessed as a bitmask. */
-      uint64_t i;
+      bitset_t i;
    } flags;
 
    /** Precision of the type (highp/medium/lowp). */