location aliasing

[jimihem]

when location aliasing, the aliases sharing the location must have the same underlying numerical type (floating-point or integer) and the same auxiliary storage and interpolation qualification. The following case, glslang need report error.

layout(vertices = 1) out;

layout (location = 1, component = 0) in double gohan[]; layout (location = 1, component = 2) in float goten[];

in vec4 vs_tcs[]; out vec4 tcs_tes[];

void main() { }

[jimihem]

@arcady-lunarg Can you help me check why this test item crash because there is no linux-asan runtime environment on my computer. [linux-asan (gcc, g++, Debug, -fsanitize=address)]

[arcady-lunarg]

I think the problem is that a vector<TIORange> is being turned into a vector<TRange> somewhere and then deallocated, and this passed ASAN because the structs were the same size somehow, and your adding new struct members changed that? But that seems like a pretty bizarre error in any case, which needs to be investigated, and I will try to look into. In any case, the information produced by ASAN is in the CI output.

[jimihem]

@arcady-lunarg Has this test crash problem been fixed ?

[arcady-lunarg]

This is a real bug, not related to your change. Apparently when qualifier.storage is equal to EvqTileImageEXT, it overruns the usedIO array and corrupts whatever is next in the TIntermediate struct. I'm going to make a patch.

[svenvh]

@jimihem after your commit, the following fragment shader results in ERROR: 0:4: 'location' : the aliases sharing the location 0 must be the same basic type and interpolation qualification:

#version 450
  
layout(location=0, component=0) flat in uint u;
layout(location=0, component=1) flat in int i;

void main() {
}

Is that intentional? My reading of the GLSL specification is that differences in signedness shouldn't matter:

Two (or more) variables that share the same location must satisfy the following conditions: Share the same base data type. So you can have alias locations for floating-point types, or integer types (signed and unsigned does not matter for this), but you cannot have a float sit alongside an integer.

[pmistryNV]

This commit will fail tests from GL CTS https://github.com/KhronosGroup/VK-GL-CTS/blob/main/external/openglcts/modules/gl/gl4cEnhancedLayoutsTests.cpp

It will error out following aliases based on mismatch in auxilary qualifiers. I think the check is not correct and must let auxilary qualifiers mismatch.

layout (location = 1, component = 0) centroid flat in int gohan; layout (location = 1, component = 1) flat in ivec3 goten;

[pmistryNV]

layout (location = 1, component = 0) centroid flat in int gohan; layout (location = 1, component = 1) flat in ivec3 goten;

Filed a bug to track this bug https://github.com/KhronosGroup/glslang/issues/3598