Mesa (master): glsl: Move built-ins to live beyond the global scope.
Ian Romanick
idr at kemper.freedesktop.org
Thu Aug 26 16:25:17 UTC 2010
Module: Mesa
Branch: master
Commit: a044285e25615f2d97636fe3ba47d580c3537bc4
URL: http://cgit.freedesktop.org/mesa/mesa/commit/?id=a044285e25615f2d97636fe3ba47d580c3537bc4
Author: Kenneth Graunke <kenneth at whitecape.org>
Date: Mon Aug 23 14:52:06 2010 -0700
glsl: Move built-ins to live beyond the global scope.
Per the GLSL 1.20 specification (presumably a clarification of 1.10).
Also, when creating user functions, make a new ir_function that shadows the
built-in ir_function, rather than adding new signatures. User functions
are supposed to hide built-ins, not overload them.
Fixes piglit tests redeclaration-{04, 12, 14}.vert.
---
src/glsl/ast_to_hir.cpp | 24 ++++++++++++++++++++----
1 files changed, 20 insertions(+), 4 deletions(-)
diff --git a/src/glsl/ast_to_hir.cpp b/src/glsl/ast_to_hir.cpp
index 9b72316..548b3d8 100644
--- a/src/glsl/ast_to_hir.cpp
+++ b/src/glsl/ast_to_hir.cpp
@@ -64,6 +64,21 @@ _mesa_ast_to_hir(exec_list *instructions, struct _mesa_glsl_parse_state *state)
state->current_function = NULL;
+ /* Section 4.2 of the GLSL 1.20 specification states:
+ * "The built-in functions are scoped in a scope outside the global scope
+ * users declare global variables in. That is, a shader's global scope,
+ * available for user-defined functions and global variables, is nested
+ * inside the scope containing the built-in functions."
+ *
+ * Since built-in functions like ftransform() access built-in variables,
+ * it follows that those must be in the outer scope as well.
+ *
+ * We push scope here to create this nesting effect...but don't pop.
+ * This way, a shader's globals are still in the symbol table for use
+ * by the linker.
+ */
+ state->symbols->push_scope();
+
foreach_list_typed (ast_node, ast, link, & state->translation_unit)
ast->hir(instructions, state);
}
@@ -1890,11 +1905,12 @@ ast_declarator_list::hir(exec_list *instructions,
/* Check if this declaration is actually a re-declaration, either to
* resize an array or add qualifiers to an existing variable.
*
- * This is allowed for variables in the current scope.
+ * This is allowed for variables in the current scope, or when at
+ * global scope (for built-ins in the implicit outer scope).
*/
ir_variable *earlier = state->symbols->get_variable(decl->identifier);
- if (earlier != NULL
- && state->symbols->name_declared_this_scope(decl->identifier)) {
+ if (earlier != NULL && (state->current_function == NULL ||
+ state->symbols->name_declared_this_scope(decl->identifier))) {
/* From page 24 (page 30 of the PDF) of the GLSL 1.50 spec,
*
@@ -2178,7 +2194,7 @@ ast_function::hir(exec_list *instructions,
* that the previously seen signature does not have an associated definition.
*/
f = state->symbols->get_function(name, false);
- if (f != NULL) {
+ if (f != NULL && !f->is_builtin) {
sig = f->exact_matching_signature(&hir_parameters);
if (sig != NULL) {
const char *badvar = sig->qualifiers_match(&hir_parameters);
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