glsl/glcpp: Fix preprocessor error condition for macro redefinition

This patch specifically fixes redefinition condition for white space
changes. #define and #undef functionality in GLSL follows the standard
for C++ preprocessors for macro definitions.

From https://gcc.gnu.org/onlinedocs/cpp/Undefining-and-Redefining-Macros.html:

These definitions are effectively the same:

     #define FOUR (2 + 2)
     #define FOUR         (2    +    2)
     #define FOUR (2 /* two */ + 2)

but these are not:

     #define FOUR (2 + 2)
     #define FOUR ( 2+2 )
     #define FOUR (2 * 2)
     #define FOUR(score,and,seven,years,ago) (2 + 2)

Fixes Khronos GLES3 CTS tests;
invalid_object_whitespace_vertex
invalid_object_whitespace_fragment

Signed-off-by: Anuj Phogat <[email protected]>
Reviewed-by: Carl Worth <[email protected]>

1 files changed, 10 insertions, 8 deletions

diff --git a/src/glsl/glcpp/glcpp-parse.y b/src/glsl/glcpp/glcpp-parse.y
index 9d8b5bbb0b6..3fc8c868b07 100644
--- a/src/glsl/glcpp/glcpp-parse.y
+++ b/src/glsl/glcpp/glcpp-parse.y
@@ -939,14 +939,16 @@ _token_list_equal_ignoring_space (token_list_t *a, token_list_t *b)
 
 		if (node_a == NULL || node_b == NULL)
 			return 0;
-
-		if (node_a->token->type == SPACE) {
-			node_a = node_a->next;
-			continue;
-		}
-
-		if (node_b->token->type == SPACE) {
-			node_b = node_b->next;
+		/* Make sure whitespace appears in the same places in both.
+		 * It need not be exactly the same amount of whitespace,
+		 * though.
+		 */
+		if (node_a->token->type == SPACE
+		    && node_b->token->type == SPACE) {
+			while (node_a->token->type == SPACE)
+				node_a = node_a->next;
+			while (node_b->token->type == SPACE)
+				node_b = node_b->next;
 			continue;
 		}