Mesa (7.10): glsl: Track variable usage, use that to enforce semantics
Ian Romanick
idr at kemper.freedesktop.org
Tue Jan 18 00:28:44 UTC 2011
Module: Mesa
Branch: 7.10
Commit: aff41708493f9145c4f424e4b37e76978e78a1c4
URL: http://cgit.freedesktop.org/mesa/mesa/commit/?id=aff41708493f9145c4f424e4b37e76978e78a1c4
Author: Ian Romanick <ian.d.romanick at intel.com>
Date: Fri Jan 7 18:34:58 2011 -0800
glsl: Track variable usage, use that to enforce semantics
In particular, variables cannot be redeclared invariant after being
used.
Fixes piglit test invariant-05.vert and bugzilla #29164.
NOTE: This is a candidate for the 7.9 and 7.10 branches.
(cherry picked from commit bd33055ef4b6dd18d6247ff7d9e47496ff4acc51)
---
src/glsl/ast_to_hir.cpp | 18 ++++++++++++++++--
src/glsl/ir.cpp | 1 +
src/glsl/ir.h | 9 +++++++++
3 files changed, 26 insertions(+), 2 deletions(-)
diff --git a/src/glsl/ast_to_hir.cpp b/src/glsl/ast_to_hir.cpp
index 9ca7932..087c143 100644
--- a/src/glsl/ast_to_hir.cpp
+++ b/src/glsl/ast_to_hir.cpp
@@ -1626,6 +1626,7 @@ ast_expression::hir(exec_list *instructions,
result = new(ctx) ir_dereference_variable(var);
if (var != NULL) {
+ var->used = true;
type = result->type;
} else {
_mesa_glsl_error(& loc, state, "`%s' undeclared",
@@ -1800,8 +1801,16 @@ apply_type_qualifier_to_variable(const struct ast_type_qualifier *qual,
struct _mesa_glsl_parse_state *state,
YYLTYPE *loc)
{
- if (qual->flags.q.invariant)
- var->invariant = 1;
+ if (qual->flags.q.invariant) {
+ if (var->used) {
+ _mesa_glsl_error(loc, state,
+ "variable `%s' may not be redeclared "
+ "`invariant' after being used",
+ var->name);
+ } else {
+ var->invariant = 1;
+ }
+ }
/* FINISHME: Mark 'in' variables at global scope as read-only. */
if (qual->flags.q.constant || qual->flags.q.attribute
@@ -2008,6 +2017,11 @@ ast_declarator_list::hir(exec_list *instructions,
_mesa_glsl_error(& loc, state,
"`%s' cannot be marked invariant, fragment shader "
"inputs only\n", decl->identifier);
+ } else if (earlier->used) {
+ _mesa_glsl_error(& loc, state,
+ "variable `%s' may not be redeclared "
+ "`invariant' after being used",
+ earlier->name);
} else {
earlier->invariant = true;
}
diff --git a/src/glsl/ir.cpp b/src/glsl/ir.cpp
index b8b0fed..2340134 100644
--- a/src/glsl/ir.cpp
+++ b/src/glsl/ir.cpp
@@ -1277,6 +1277,7 @@ ir_variable::ir_variable(const struct glsl_type *type, const char *name,
this->constant_value = NULL;
this->origin_upper_left = false;
this->pixel_center_integer = false;
+ this->used = false;
if (type && type->base_type == GLSL_TYPE_SAMPLER)
this->read_only = true;
diff --git a/src/glsl/ir.h b/src/glsl/ir.h
index 102a68b..719d90c 100644
--- a/src/glsl/ir.h
+++ b/src/glsl/ir.h
@@ -295,6 +295,15 @@ public:
unsigned invariant:1;
/**
+ * Has this variable been used for reading or writing?
+ *
+ * Several GLSL semantic checks require knowledge of whether or not a
+ * variable has been used. For example, it is an error to redeclare a
+ * variable as invariant after it has been used.
+ */
+ unsigned used:1;
+
+ /**
* Storage class of the variable.
*
* \sa ir_variable_mode
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