Vulkan: Fix issue in GlslWrapper and maxVaryingVectors calculation (2nd try)

src/libANGLE/renderer/vulkan/GlslangWrapper.cpp

@@ -108,11 +108,12 @@ gl::LinkResult GlslangWrapper::linkProgram(const gl::Context *glContext,
     }
 
     // Assign varying locations.
-    // TODO(jmadill): This might need to be redone.
     for (const auto &varyingReg : resources.varyingPacking.getRegisterList())
     {
         const auto &varying        = *varyingReg.packedVarying;
-        std::string locationString = "location = " + Str(varyingReg.registerRow);
+
+        std::string locationString = "location = " + Str(varyingReg.registerRow) +
+                                     ", component = " + Str(varyingReg.registerColumn);
         InsertLayoutSpecifierString(&vertexSource, varying.varying->name, locationString);
         InsertLayoutSpecifierString(&fragmentSource, varying.varying->name, locationString);
     }

src/libANGLE/renderer/vulkan/vk_caps_utils.cpp

@@ -121,10 +121,13 @@ void GenerateCaps(const VkPhysicalDeviceProperties &physicalDeviceProperties,
     outCaps->maxVertexTextureImageUnits =
         physicalDeviceProperties.limits.maxPerStageDescriptorSamplers;
 
-    // The max vertex output components includes the reserved varyings like gl_PointSize,
-    // gl_PointCoord, gl_Position, and gl_FragColor. On a vertex shader, you can only have
-    // gl_PointCoord and gl_Position, and on a fragment shader you can have gl_PointSize and
-    // gl_FragColor, so the reserved varying count is always 2 at most.
+    // The max vertex output components should not include gl_Position.
+    // The gles2.0 section 2.10 states that "gl_Position is not a varying variable and does
+    // not count against this limit.", but the Vulkan spec has no such mention in its Built-in
+    // vars section. It is implicit that we need to actually reserve it for Vulkan in that case.
+    // TODO(lucferron): AMD has a weird behavior when we edge toward the maximum number of varyings
+    // and can often crash. Reserving an additional varying just for them bringing the total to 2.
+    // http://anglebug.com/2483
     constexpr GLint kReservedVaryingCount = 2;
     outCaps->maxVaryingVectors =
         (physicalDeviceProperties.limits.maxVertexOutputComponents / 4) - kReservedVaryingCount;

src/tests/gl_tests/GLSLTest.cpp

@@ -1255,10 +1255,6 @@ TEST_P(GLSLTest, MaxVaryingsSpecialCases)
 // rather than total register use.
 TEST_P(GLSLTest, MaxMinusTwoVaryingVec2PlusOneSpecialVariable)
 {
-    // TODO(lucferron): Root cause and fix it. Looks like a location is used twice (loc = 31).
-    // http://anglebug.com/2460
-    ANGLE_SKIP_TEST_IF(IsVulkan());
-
     GLint maxVaryings = 0;
     glGetIntegerv(GL_MAX_VARYING_VECTORS, &maxVaryings);
 
@@ -1285,11 +1281,6 @@ TEST_P(GLSLTest, MaxVaryingVec3Array)
 // Only fails on D3D9 because of packing limitations.
 TEST_P(GLSLTest, MaxVaryingVec3AndOneFloat)
 {
-    // TODO(lucferron): Root cause and fix it.
-    // ERROR: 0:62: 'location' : overlapping use of location x
-    // http://anglebug.com/2460
-    ANGLE_SKIP_TEST_IF(IsVulkan());
-
     GLint maxVaryings = 0;
     glGetIntegerv(GL_MAX_VARYING_VECTORS, &maxVaryings);
 
@@ -1299,11 +1290,6 @@ TEST_P(GLSLTest, MaxVaryingVec3AndOneFloat)
 // Only fails on D3D9 because of packing limitations.
 TEST_P(GLSLTest, MaxVaryingVec3ArrayAndOneFloatArray)
 {
-    // TODO(lucferron): Root cause and fix it.
-    // ERROR: 0:62: 'location' : overlapping use of location x
-    // http://anglebug.com/2460
-    ANGLE_SKIP_TEST_IF(IsVulkan());
-
     GLint maxVaryings = 0;
     glGetIntegerv(GL_MAX_VARYING_VECTORS, &maxVaryings);
 
@@ -1313,11 +1299,6 @@ TEST_P(GLSLTest, MaxVaryingVec3ArrayAndOneFloatArray)
 // Only fails on D3D9 because of packing limitations.
 TEST_P(GLSLTest, TwiceMaxVaryingVec2)
 {
-    // TODO(lucferron): Root cause and fix it.
-    // ERROR: 0:62: 'location' : overlapping use of location x
-    // http://anglebug.com/2460
-    ANGLE_SKIP_TEST_IF(IsVulkan());
-
     // TODO(geofflang): Figure out why this fails on NVIDIA's GLES driver
     ANGLE_SKIP_TEST_IF(IsNVIDIA() && IsOpenGLES());
 
@@ -1334,11 +1315,6 @@ TEST_P(GLSLTest, TwiceMaxVaryingVec2)
 // Disabled because of a failure in D3D9
 TEST_P(GLSLTest, MaxVaryingVec2Arrays)
 {
-    // TODO(lucferron): Root cause and fix it.
-    // ERROR: 0:62: 'location' : overlapping use of location x
-    // http://anglebug.com/2460
-    ANGLE_SKIP_TEST_IF(IsVulkan());
-
     ANGLE_SKIP_TEST_IF(IsD3DSM3());
 
     // TODO(geofflang): Figure out why this fails on NVIDIA's GLES driver