Vulkan: Support vertex attribute aliasing for matrix types

This change builds on vertex attribute aliasing SPIR-V tranformation for
non-matrix types to add support for matrix attribute types.  This is
done by turning every matrix attribute declaration into multiple vector
attribute declarations, and reusing the same mechanism for resolving
aliasing between non-matrix types.

Take the following example:

    attribute mat4 a; // location 0
    attribute vec3 b; // location 1

    attribute mat3 c; // location 1
    attribute vec4 d; // location 2

The shader is modified as such:

    attribute vec4 a_0; // location 0
    attribute vec4 a_1; // location 1
    attribute vec4 a_2; // location 2
    attribute vec4 a_3; // location 3

    attribute vec3 c_0; // location 4
    attribute vec4 d;   // location 5
    attribute vec3 c_2; // location 6

    mat4 a;
    mat3 c;

and in the beginning of main(), the following code is inserted:

    a = mat4(a_0, a_1, a_2, a_3);
    c = mat3(c_0, d.xyz, c_2);

The shader continues to use a and c as before.

Bug: angleproject:4249
Change-Id: Idfcb8c6037ca0c1f21de8203d7e2a1b66fed6e7e
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2488128
Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org>
Reviewed-by: Charlie Lao <cclao@google.com>
Reviewed-by: Courtney Goeltzenleuchter <courtneygo@google.com>

src/libANGLE/renderer/glslang_wrapper_utils.h

@@ -88,13 +88,10 @@ struct ShaderInterfaceVariableInfo
     bool useRelaxedPrecision = false;
     // Indicate if varying is input or output
     bool varyingIsOutput = false;
-    // For vertex attributes, this is the number of components.  This is used by the vertex
-    // attribute aliasing transformation only.
+    // For vertex attributes, this is the number of components / locations.  These are used by the
+    // vertex attribute aliasing transformation only.
     uint8_t attributeComponentCount = 0;
-    // Indicate whether this is a vertex attribute of matrix type.  This is temporarily used to
-    // avoid handling aliasing matrix vertex attributes as they are currently not supported.
-    // TODO: remove when support for aliasing matrix attributes is added.  http://anglebug.com/4249
-    bool isMatrixAttribute = false;
+    uint8_t attributeLocationCount  = 0;
 };
 
 // TODO: http://anglebug.com/4524: Need a different hash key than a string, since

src/libANGLE/renderer/vulkan/ProgramExecutableVk.cpp

@@ -226,7 +226,7 @@ std::unique_ptr<rx::LinkEvent> ProgramExecutableVk::load(gl::BinaryInputStream *
             info->useRelaxedPrecision     = stream->readBool();
             info->varyingIsOutput         = stream->readBool();
             info->attributeComponentCount = stream->readInt<uint8_t>();
-            info->isMatrixAttribute       = stream->readBool();
+            info->attributeLocationCount  = stream->readInt<uint8_t>();
         }
     }
 
@@ -253,7 +253,7 @@ void ProgramExecutableVk::save(gl::BinaryOutputStream *stream)
             stream->writeInt<uint8_t>(it.second.useRelaxedPrecision);
             stream->writeInt<uint8_t>(it.second.varyingIsOutput);
             stream->writeInt<uint8_t>(it.second.attributeComponentCount);
-            stream->writeInt<uint8_t>(it.second.isMatrixAttribute);
+            stream->writeInt<uint8_t>(it.second.attributeLocationCount);
         }
     }
 }

src/tests/deqp_support/deqp_gles2_test_expectations.txt

@@ -427,9 +427,6 @@
 // Fails on 431.02 NVIDIA driver
 3748 VULKAN WIN NVIDIA : dEQP-GLES2.functional.fbo.render.repeated_clear.* = FAIL
 
-// Vertex attribute aliasing generates invalid SPIRV
-4249 VULKAN : dEQP-GLES2.functional.attribute_location.bind_aliasing.*mat* = SKIP
-
 // Fails on Metal, some of filtering tests fail when MSAA is off and pass when MSAA is on. Some
 // tests are opposite. The filtering tests mostly fail on a few pixels.
 4235 METAL AMD : dEQP-GLES2.functional.shaders.texture_functions.vertex.texturecubelod = FAIL
@@ -501,9 +498,6 @@
 // Line loop emulation bug, suspected to be caused by wrong segment order
 4853 METAL AMD : dEQP-GLES2.functional.draw.draw_arrays.line_loop.multiple_attributes = FAIL
 
-// Vertex attribute aliasing generates invalid SPIRV
-4249 METAL : dEQP-GLES2.functional.attribute_location.bind_aliasing.*mat* = SKIP
-
 // Globally disable Metal testing on Intel & NVIDIA for now
 4235 METAL INTEL : dEQP-GLES2.* = SKIP
 4235 METAL NVIDIA : dEQP-GLES2.* = SKIP

src/tests/gl_tests/VertexAttributeTest.cpp

@@ -3202,11 +3202,6 @@ void main()
 // don't allow vertex attribute aliasing.  This test includes matrix types.
 TEST_P(VertexAttributeTest, AliasingMatrixAttribLocations)
 {
-    // TODO(syoussefi): Support vertex attribute aliasing on Vulkan.  The metal backend will
-    // automatically be fixed in the process.  http://anglebug.com/4249
-    ANGLE_SKIP_TEST_IF(IsVulkan());
-    ANGLE_SKIP_TEST_IF(IsMetal());
-
     // http://anglebug.com/5180
     ANGLE_SKIP_TEST_IF(IsAndroid() && IsOpenGL());