[Mesa-dev] [PATCH v2 0/8] glsl/linker: fix location aliasing checks

[Iago Toral Quiroga]

This v2 series is in fact an update and merge of the these two series:
"glsl/linker: fix location aliasing checks" and "Implement location aliasing
checks for SSO programs" 

This v2 series introduces 3 changes:

1. Use MAX_VARYINGS instead of MAX_VARYINGS_INCL_PATCH to define the size
   of the explicit_locations array. This change, however, made a pre-existing
   bug  show up: we do not check that explicit locations on inputs are valid
   (< MAX_VARYINGS) before indexing the explicit_locations array. That can lead
   to out of bounds accesses. There are some tests in dEQP and CTS that check this
   however, because we were using MAX_VARYINGS_INCL_PATCH as the size of the
   array, we were sill indexing inside the bounds of the array (even if the
   location index was not correct) and we would still produce linker errors
   when we didn't found matching outputs, however that was just luck, as we
   could still be indexing out of bounds if the invalid location provided for
   shader inputs were large enough. The first patch in this v2 series fixes
   this by adding a trivial check for the input location index.

2. For SSO, we only need to validate location aliasing for the inputs to the
   first stage and outputs of the last stage, as pointed out by Timothy. This
   is addressed in the last patch in the series.

3. When we were validating interface block locations, we were not computing
   correctly the location slot index for patch variables (these start at
   VARYING_SLOT_PATCH0 not VARYING_SLOT_VAR0).

Illia: I also checked your original patch and I think this series includes
all functional changes you had.

Patches 2-7 are already reviewed, changes 1) and 3) affect some of them but
trivially so. Patches 1 (new in this series) and 8 still need the Rb.

Iago Toral Quiroga (8):
  glsl/linker: report linker errors for invalid explicit locations on
    inputs
  glsl/linker: refactor link-time validation of output locations
  glsl/linker: fix location aliasing checks for interface variables
  glsl/linker: outputs in the same location must share interpolation
  glsl/linker: outputs in the same location must share auxiliary storage
  glsl/linker: create a helper function to validate explicit locations
  glsl/linker: generalize validate_explicit_variable_location for SSO
  glsl/linker: validate explicit locations for SSO programs

 src/compiler/glsl/link_varyings.cpp | 334 ++++++++++++++++++++++++++++--------
 src/compiler/glsl/link_varyings.h   |   6 +
 src/compiler/glsl/linker.cpp        |  10 ++
 3 files changed, 279 insertions(+), 71 deletions(-)

-- 
2.11.0