Re: [Mesa-dev] [PATCH v4] glsl/blob: avoid NULL ptr in prog parameter name

[Timothy Arceri]

I've pushed this. Thanks for getting to the bottom of the problem :)
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[Mesa-dev] [PATCH v4] glsl/blob: avoid NULL ptr in prog parameter name

[Gregory Hainaut]

Context: _mesa_add_parameter is sometimes[0] called with a
NULL name as a mean of an unnamed parameter.

Allowing NULL pointer as a name means that it must be NULL checked
each access. So far it isn't always[1] true.

Parameter name is only used for debug purpose (printf) and
to lookup the index/location of the program by the application.

Conclusion, there is no valid reason to use a NULL pointer instead of
an empty string. So it was decided to use an empty string which avoid all
issues related to NULL pointer

[0]: texture gather offsets glsl opcode and st_init_atifs_prog
[1]: at least shader cache, st_nir_lookup_parameter_index and some printfs

Issue found by piglit 'texturegatheroffsets' tests on Nouveau

v4: new patch based on Nicolai/Timothy/ilia discussion
Signed-off-by: Gregory Hainaut 
---
 src/mesa/program/prog_parameter.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/mesa/program/prog_parameter.c 
b/src/mesa/program/prog_parameter.c
index c294b00..6689c71 100644
--- a/src/mesa/program/prog_parameter.c
+++ b/src/mesa/program/prog_parameter.c
@@ -258,7 +258,7 @@ _mesa_add_parameter(struct gl_program_parameter_list 
*paramList,
 
for (i = 0; i < sz4; i++) {
   struct gl_program_parameter *p = paramList->Parameters + oldNum + i;
-  p->Name = name ? strdup(name) : NULL;
+  p->Name = strdup(name ? name : "");
   p->Type = type;
   p->Size = size;
   p->DataType = datatype;
-- 
2.1.4

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