Mesa (staging/19.1): glsl: Fix out of bounds read in shader_cache_read_program_metadata

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Module: Mesa
Branch: staging/19.1
Commit: 47f1f4f9e5199205af6ae25a8bd411e946fcc427
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=47f1f4f9e5199205af6ae25a8bd411e946fcc427

Author: Kenneth Graunke <kenneth at whitecape.org>
Date:   Fri Jun  7 23:00:40 2019 -0700

glsl: Fix out of bounds read in shader_cache_read_program_metadata

The VaryingNames array has NumVaryings entries.  But BufferStride is
a small array of MAX_FEEDBACK_BUFFERS (4) entries.  Programs with
more than 4 varyings would read out of bounds.

Also, BufferStride is set based on the shader itself, which means that
it's inherently already included in the hash, and doesn't need to be
included again.  At the point when shader_cache_read_program_metadata
is called, the linker hasn't even set those fields yet.  So, just drop
it entirely.

Fixes valgrind errors in KHR-GL45.transform_feedback.linking_errors_test.

Fixes: 6d830940f78 glsl/shader_cache: Allow shader cache usage with transform feedback

Reviewed-by: Timothy Arceri <tarceri at itsqueeze.com>
(cherry picked from commit 3c10a2726bcf686f03e31e79e40786e3894ff063)

---

 src/compiler/glsl/shader_cache.cpp | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/src/compiler/glsl/shader_cache.cpp b/src/compiler/glsl/shader_cache.cpp
index 581098b88f0..97049043345 100644
--- a/src/compiler/glsl/shader_cache.cpp
+++ b/src/compiler/glsl/shader_cache.cpp
@@ -165,9 +165,8 @@ shader_cache_read_program_metadata(struct gl_context *ctx,
    prog->FragDataIndexBindings->iterate(create_binding_str, &buf);
    ralloc_asprintf_append(&buf, "tf: %d ", prog->TransformFeedback.BufferMode);
    for (unsigned int i = 0; i < prog->TransformFeedback.NumVarying; i++) {
-      ralloc_asprintf_append(&buf, "%s:%d ",
-                             prog->TransformFeedback.VaryingNames[i],
-                             prog->TransformFeedback.BufferStride[i]);
+      ralloc_asprintf_append(&buf, "%s ",
+                             prog->TransformFeedback.VaryingNames[i]);
    }
 
    /* SSO has an effect on the linked program so include this when generating