From: Carl Worth <cworth@cworth.org>
Date: Fri, 8 Jun 2012 22:00:49 +0000 (-0700)
Subject: glsl: glcpp: Allow "#if undefined-macro' to evaluate to false.
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=c96b8302a398a6db27f1bb6070cdc088c7ee0fba;p=mesa.git

glsl: glcpp: Allow "#if undefined-macro' to evaluate to false.

A strict reading of the GLSL specification would have this be an
error, but we've received reports from users who expect the
preprocessor to interepret undefined macros as 0. This is the standard
behavior of the rpeprocessor for C, and according to these user
reports is also the behavior of other OpenGL implementations.

So here's one of those cases where we can make our users happier by
ignoring the specification. And it's hard to imagine users who really,
really want to see an error for this case.

The two affected tests cases are updated to reflect the new behavior.

Signed-off-by: Carl Worth <cworth@cworth.org>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
---

diff --git a/src/glsl/glcpp/glcpp-parse.y b/src/glsl/glcpp/glcpp-parse.y
index 9e8f9b2d653..78ff8fa9c59 100644
--- a/src/glsl/glcpp/glcpp-parse.y
+++ b/src/glsl/glcpp/glcpp-parse.y
@@ -341,6 +341,9 @@ integer_constant:
 
 expression:
 	integer_constant
+|	IDENTIFIER {
+		$$ = 0;
+	}
 |	expression OR expression {
 		$$ = $1 || $3;
 	}
diff --git a/src/glsl/glcpp/tests/070-undefined-macro-in-expression.c b/src/glsl/glcpp/tests/070-undefined-macro-in-expression.c
index b6dc2ba075f..d15a4840b01 100644
--- a/src/glsl/glcpp/tests/070-undefined-macro-in-expression.c
+++ b/src/glsl/glcpp/tests/070-undefined-macro-in-expression.c
@@ -1,2 +1,5 @@
 #if UNDEFINED_MACRO
+Failure
+#else
+Success
 #endif
diff --git a/src/glsl/glcpp/tests/070-undefined-macro-in-expression.c.expected b/src/glsl/glcpp/tests/070-undefined-macro-in-expression.c.expected
index 2bb38a1411e..d5a84525579 100644
--- a/src/glsl/glcpp/tests/070-undefined-macro-in-expression.c.expected
+++ b/src/glsl/glcpp/tests/070-undefined-macro-in-expression.c.expected
@@ -1,2 +1,6 @@
-0:1(21): preprocessor error: syntax error, unexpected IDENTIFIER
+
+
+
+Success
+
 
diff --git a/src/glsl/glcpp/tests/098-elif-undefined.c b/src/glsl/glcpp/tests/098-elif-undefined.c
index 52a331cc414..1f520d4d432 100644
--- a/src/glsl/glcpp/tests/098-elif-undefined.c
+++ b/src/glsl/glcpp/tests/098-elif-undefined.c
@@ -1,3 +1,7 @@
 #if 0
+Not this
 #elif UNDEFINED_MACRO
+Nor this
+#else
+Yes, this.
 #endif
diff --git a/src/glsl/glcpp/tests/098-elif-undefined.c.expected b/src/glsl/glcpp/tests/098-elif-undefined.c.expected
index de967eac438..2af0a12690a 100644
--- a/src/glsl/glcpp/tests/098-elif-undefined.c.expected
+++ b/src/glsl/glcpp/tests/098-elif-undefined.c.expected
@@ -1,5 +1,8 @@
-0:2(22): preprocessor error: syntax error, unexpected IDENTIFIER
-0:1(7): preprocessor error: Unterminated #if
 
 
 
+
+
+Yes, this.
+
+