Implement GL_EXT_fragment_invocation_density

including SPV generation using SPV_EXT_fragment_invocation_density.
This is an alias of the functionality in SPV_NV_shading_rate, and thus in some
cases we can only have one set of the tokens present (switch statements), so
we have picked the EXT version. This required updating the expected test
results for SPV_NV_shading_rate.

Also updated the known-good for spirv-headers so that the validator in
spirv-tools knows about the new extension.

SPIRV/GLSL.ext.EXT.h

@@ -28,10 +28,11 @@
 #define GLSLextEXT_H
 
 static const int GLSLextEXTVersion = 100;
-static const int GLSLextEXTRevision = 1;
+static const int GLSLextEXTRevision = 2;
 
 static const char* const E_SPV_EXT_shader_stencil_export        = "SPV_EXT_shader_stencil_export";
 static const char* const E_SPV_EXT_shader_viewport_index_layer  = "SPV_EXT_shader_viewport_index_layer";
 static const char* const E_SPV_EXT_fragment_fully_covered = "SPV_EXT_fragment_fully_covered";
+static const char* const E_SPV_EXT_fragment_invocation_density = "SPV_EXT_fragment_invocation_density";
 
 #endif  // #ifndef GLSLextEXT_H

SPIRV/GlslangToSpv.cpp

@@ -833,6 +833,16 @@ spv::BuiltIn TGlslangToSpvTraverser::TranslateBuiltInDecoration(glslang::TBuiltI
         builder.addCapability(spv::CapabilityMultiView);
         return spv::BuiltInViewIndex;
 
+    case glslang::EbvFragSizeEXT:
+        builder.addExtension(spv::E_SPV_EXT_fragment_invocation_density);
+        builder.addCapability(spv::CapabilityFragmentDensityEXT);
+        return spv::BuiltInFragSizeEXT;
+
+    case glslang::EbvFragInvocationCountEXT:
+        builder.addExtension(spv::E_SPV_EXT_fragment_invocation_density);
+        builder.addCapability(spv::CapabilityFragmentDensityEXT);
+        return spv::BuiltInFragInvocationCountEXT;
+
 #ifdef NV_EXTENSIONS
     case glslang::EbvViewportMaskNV:
         if (!memberDeclaration) {

SPIRV/doc.cpp

@@ -388,12 +388,15 @@ const char* BuiltInString(int builtIn)
     case BuiltInSecondaryViewportMaskNV:    return "SecondaryViewportMaskNV";
     case BuiltInPositionPerViewNV:          return "PositionPerViewNV";
     case BuiltInViewportMaskPerViewNV:      return "ViewportMaskPerViewNV";
-    case BuiltInFragmentSizeNV:             return "FragmentSizeNV";
+//    case BuiltInFragmentSizeNV:             return "FragmentSizeNV";        // superseded by BuiltInFragSizeEXT
-    case BuiltInInvocationsPerPixelNV:      return "InvocationsPerPixelNV";
+//    case BuiltInInvocationsPerPixelNV:      return "InvocationsPerPixelNV"; // superseded by BuiltInFragInvocationCountEXT
     case BuiltInBaryCoordNV:                return "BaryCoordNV";
     case BuiltInBaryCoordNoPerspNV:         return "BaryCoordNoPerspNV";
 #endif
 
+    case BuiltInFragSizeEXT:                return "FragSizeEXT";
+    case BuiltInFragInvocationCountEXT:     return "FragInvocationCountEXT";
+
     case 5264: return "FullyCoveredEXT";
 
 
@@ -897,8 +900,9 @@ const char* CapabilityString(int info)
     case CapabilityComputeDerivativeGroupLinearNV:  return "ComputeDerivativeGroupLinearNV";
     case CapabilityFragmentBarycentricNV:           return "FragmentBarycentricNV";
     case CapabilityMeshShadingNV:                   return "MeshShadingNV";
-    case CapabilityShadingRateNV:                   return "ShadingRateNV";
+//    case CapabilityShadingRateNV:                   return "ShadingRateNV";  // superseded by CapabilityFragmentDensityEXT
 #endif
+    case CapabilityFragmentDensityEXT:              return "FragmentDensityEXT";
 
     case CapabilityFragmentFullyCoveredEXT: return "FragmentFullyCoveredEXT";
 

Test/baseResults/spv.fragmentDensity-es.frag.out

@@ -0,0 +1,45 @@
+spv.fragmentDensity-es.frag
+// Module Version 10000
+// Generated by (magic number): 80007
+// Id's are bound by 18
+
+                              Capability Shader
+                              Capability FragmentDensityEXT
+                              Extension  "SPV_EXT_fragment_invocation_density"
+               1:             ExtInstImport  "GLSL.std.450"
+                              MemoryModel Logical GLSL450
+                              EntryPoint Fragment 4  "main" 9 11 14 16
+                              ExecutionMode 4 OriginUpperLeft
+                              Source ESSL 310
+                              SourceExtension  "GL_EXT_fragment_invocation_density"
+                              Name 4  "main"
+                              Name 9  "FragSize"
+                              Name 11  "gl_FragSizeEXT"
+                              Name 14  "FragInvocationCount"
+                              Name 16  "gl_FragInvocationCountEXT"
+                              Decorate 9(FragSize) Location 0
+                              Decorate 11(gl_FragSizeEXT) Flat
+                              Decorate 11(gl_FragSizeEXT) BuiltIn FragSizeEXT
+                              Decorate 14(FragInvocationCount) Location 2
+                              Decorate 16(gl_FragInvocationCountEXT) Flat
+                              Decorate 16(gl_FragInvocationCountEXT) BuiltIn FragInvocationCountEXT
+               2:             TypeVoid
+               3:             TypeFunction 2
+               6:             TypeInt 32 1
+               7:             TypeVector 6(int) 2
+               8:             TypePointer Output 7(ivec2)
+     9(FragSize):      8(ptr) Variable Output
+              10:             TypePointer Input 7(ivec2)
+11(gl_FragSizeEXT):     10(ptr) Variable Input
+              13:             TypePointer Output 6(int)
+14(FragInvocationCount):     13(ptr) Variable Output
+              15:             TypePointer Input 6(int)
+16(gl_FragInvocationCountEXT):     15(ptr) Variable Input
+         4(main):           2 Function None 3
+               5:             Label
+              12:    7(ivec2) Load 11(gl_FragSizeEXT)
+                              Store 9(FragSize) 12
+              17:      6(int) Load 16(gl_FragInvocationCountEXT)
+                              Store 14(FragInvocationCount) 17
+                              Return
+                              FunctionEnd

Test/baseResults/spv.fragmentDensity-neg.frag.out

@@ -0,0 +1,7 @@
+spv.fragmentDensity-neg.frag
+ERROR: 0:10: 'gl_FragSizeEXT' : required extension not requested: GL_EXT_fragment_invocation_density
+ERROR: 0:11: 'gl_FragInvocationCountEXT' : required extension not requested: GL_EXT_fragment_invocation_density
+ERROR: 2 compilation errors.  No code generated.
+
+
+SPIR-V is not generated for failed compile or link

Test/baseResults/spv.fragmentDensity.frag.out

@@ -0,0 +1,48 @@
+spv.fragmentDensity.frag
+// Module Version 10000
+// Generated by (magic number): 80007
+// Id's are bound by 21
+
+                              Capability Shader
+                              Capability FragmentDensityEXT
+                              Extension  "SPV_EXT_fragment_invocation_density"
+               1:             ExtInstImport  "GLSL.std.450"
+                              MemoryModel Logical GLSL450
+                              EntryPoint Fragment 4  "main" 9 13 17 19
+                              ExecutionMode 4 OriginUpperLeft
+                              Source GLSL 450
+                              SourceExtension  "GL_EXT_fragment_invocation_density"
+                              Name 4  "main"
+                              Name 9  "FragSize"
+                              Name 13  "gl_FragSizeEXT"
+                              Name 17  "FragInvocationCount"
+                              Name 19  "gl_FragInvocationCountEXT"
+                              Decorate 9(FragSize) Location 0
+                              Decorate 13(gl_FragSizeEXT) Flat
+                              Decorate 13(gl_FragSizeEXT) BuiltIn FragSizeEXT
+                              Decorate 17(FragInvocationCount) Location 2
+                              Decorate 19(gl_FragInvocationCountEXT) Flat
+                              Decorate 19(gl_FragInvocationCountEXT) BuiltIn FragInvocationCountEXT
+               2:             TypeVoid
+               3:             TypeFunction 2
+               6:             TypeFloat 32
+               7:             TypeVector 6(float) 2
+               8:             TypePointer Output 7(fvec2)
+     9(FragSize):      8(ptr) Variable Output
+              10:             TypeInt 32 1
+              11:             TypeVector 10(int) 2
+              12:             TypePointer Input 11(ivec2)
+13(gl_FragSizeEXT):     12(ptr) Variable Input
+              16:             TypePointer Output 10(int)
+17(FragInvocationCount):     16(ptr) Variable Output
+              18:             TypePointer Input 10(int)
+19(gl_FragInvocationCountEXT):     18(ptr) Variable Input
+         4(main):           2 Function None 3
+               5:             Label
+              14:   11(ivec2) Load 13(gl_FragSizeEXT)
+              15:    7(fvec2) ConvertSToF 14
+                              Store 9(FragSize) 15
+              20:     10(int) Load 19(gl_FragInvocationCountEXT)
+                              Store 17(FragInvocationCount) 20
+                              Return
+                              FunctionEnd

Test/baseResults/spv.fragmentDensity.vert.out

@@ -0,0 +1,9 @@
+spv.fragmentDensity.vert
+ERROR: 0:10: 'gl_FragSizeEXT' : undeclared identifier 
+ERROR: 0:10: 'assign' :  cannot convert from ' temp float' to 'layout( location=0) smooth out highp 2-component vector of uint'
+ERROR: 0:11: 'gl_FragInvocationCountEXT' : undeclared identifier 
+ERROR: 0:11: 'assign' :  cannot convert from ' temp float' to 'layout( location=2) smooth out highp int'
+ERROR: 4 compilation errors.  No code generated.
+
+
+SPIR-V is not generated for failed compile or link

Test/baseResults/spv.shadingRate.frag.out

@@ -4,7 +4,7 @@ spv.shadingRate.frag
 // Id's are bound by 21
 
                               Capability Shader
-                              Capability ShadingRateNV
+                              Capability FragmentDensityEXT
                               Extension  "SPV_NV_shading_rate"
                1:             ExtInstImport  "GLSL.std.450"
                               MemoryModel Logical GLSL450
@@ -19,10 +19,10 @@ spv.shadingRate.frag
                               Name 19  "gl_InvocationsPerPixelNV"
                               Decorate 9(FragmentSize) Location 0
                               Decorate 13(gl_FragmentSizeNV) Flat
-                              Decorate 13(gl_FragmentSizeNV) BuiltIn FragmentSizeNV
+                              Decorate 13(gl_FragmentSizeNV) BuiltIn FragSizeEXT
                               Decorate 17(InvocationsPerPixel) Location 2
                               Decorate 19(gl_InvocationsPerPixelNV) Flat
-                              Decorate 19(gl_InvocationsPerPixelNV) BuiltIn InvocationsPerPixelNV
+                              Decorate 19(gl_InvocationsPerPixelNV) BuiltIn FragInvocationCountEXT
                2:             TypeVoid
                3:             TypeFunction 2
                6:             TypeFloat 32

Test/spv.fragmentDensity-es.frag

@@ -0,0 +1,11 @@
+#version 310 es
+
+#extension GL_EXT_fragment_invocation_density : require
+
+layout (location = 0) out highp ivec2 FragSize;
+layout (location = 2) out highp int FragInvocationCount;
+
+void main () {
+    FragSize = gl_FragSizeEXT;
+    FragInvocationCount = gl_FragInvocationCountEXT;
+}

Test/spv.fragmentDensity-neg.frag

@@ -0,0 +1,12 @@
+#version 450
+
+//make sure the builtins don't exist if the extension isn't enabled.
+//#extension GL_EXT_fragment_invocation_density : require
+
+layout (location = 0) out vec2 FragSize;
+layout (location = 2) out int FragInvocationCount;
+
+void main () {
+    FragSize = gl_FragSizeEXT;
+    FragInvocationCount = gl_FragInvocationCountEXT;
+}

Test/spv.fragmentDensity.frag

@@ -0,0 +1,11 @@
+#version 450
+
+#extension GL_EXT_fragment_invocation_density : require
+
+layout (location = 0) out vec2 FragSize;
+layout (location = 2) out int FragInvocationCount;
+
+void main () {
+    FragSize = gl_FragSizeEXT;
+    FragInvocationCount = gl_FragInvocationCountEXT;
+}

Test/spv.fragmentDensity.vert

@@ -0,0 +1,12 @@
+#version 450
+
+// try using a fragment-only extension in a vertex shader
+#extension GL_EXT_fragment_invocation_density : require
+
+layout (location = 0) out uvec2 FragSize;
+layout (location = 2) out int FragInvocationCount;
+
+void main () {
+    FragSize = gl_FragSizeEXT;
+    FragInvocationCount = gl_FragInvocationCountEXT;
+}

glslang/Include/BaseTypes.h

@@ -232,6 +232,9 @@ enum TBuiltInVariable {
     EbvViewIndex,
     EbvDeviceIndex,
 
+    EbvFragSizeEXT,
+    EbvFragInvocationCountEXT,
+
 #ifdef NV_EXTENSIONS
     EbvViewportMaskNV,
     EbvSecondaryPositionNV,
@@ -404,6 +407,9 @@ __inline const char* GetBuiltInVariableString(TBuiltInVariable v)
     case EbvViewIndex:                  return "ViewIndex";
     case EbvDeviceIndex:                return "DeviceIndex";
 
+    case EbvFragSizeEXT:                return "FragSizeEXT";
+    case EbvFragInvocationCountEXT:     return "FragInvocationCountEXT";
+
 #ifdef NV_EXTENSIONS
     case EbvViewportMaskNV:             return "ViewportMaskNV";
     case EbvSecondaryPositionNV:        return "SecondaryPositionNV";

glslang/MachineIndependent/Initialize.cpp

@@ -5939,6 +5939,12 @@ void TBuiltIns::initialize(int version, EProfile profile, const SpvVersion& spvV
                 "bool gl_HelperInvocation;"     // needs qualifier fixed later
                 );
 
+        if (version >= 450)
+            stageBuiltins[EShLangFragment].append( // GL_EXT_fragment_invocation_density
+                "flat in ivec2 gl_FragSizeEXT;"
+                "flat in int   gl_FragInvocationCountEXT;"
+                );
+
 #ifdef AMD_EXTENSIONS
         if (version >= 450)
             stageBuiltins[EShLangFragment].append(
@@ -5959,9 +5965,9 @@ void TBuiltIns::initialize(int version, EProfile profile, const SpvVersion& spvV
                 );
         if (version >= 450)
             stageBuiltins[EShLangFragment].append(
-                "flat in ivec2 gl_FragmentSizeNV;"
+                "flat in ivec2 gl_FragmentSizeNV;"          // GL_NV_shading_rate_image
                 "flat in int   gl_InvocationsPerPixelNV;"
-                "in vec3 gl_BaryCoordNV;"
+                "in vec3 gl_BaryCoordNV;"                   // GL_NV_fragment_shader_barycentric
                 "in vec3 gl_BaryCoordNoPerspNV;"
                 );
 
@@ -6006,13 +6012,19 @@ void TBuiltIns::initialize(int version, EProfile profile, const SpvVersion& spvV
         stageBuiltins[EShLangFragment].append(
             "highp float gl_FragDepthEXT;"       // GL_EXT_frag_depth
             );
+
+        if (version >= 310)
+            stageBuiltins[EShLangFragment].append( // GL_EXT_fragment_invocation_density
+                "flat in ivec2 gl_FragSizeEXT;"
+                "flat in int   gl_FragInvocationCountEXT;"
+            );
 #ifdef NV_EXTENSIONS
         if (version >= 320)
-            stageBuiltins[EShLangFragment].append(
+            stageBuiltins[EShLangFragment].append( // GL_NV_shading_rate_image
                 "flat in ivec2 gl_FragmentSizeNV;"
                 "flat in int   gl_InvocationsPerPixelNV;"
             );
-       if (version >= 320)
+        if (version >= 320)
             stageBuiltins[EShLangFragment].append(
                 "in vec3 gl_BaryCoordNV;"
                 "in vec3 gl_BaryCoordNoPerspNV;"
@@ -8342,6 +8354,14 @@ void TBuiltIns::identifyBuiltIns(int version, EProfile profile, const SpvVersion
         }
 #endif
 
+        if ((profile != EEsProfile && version >= 450) ||
+            (profile == EEsProfile && version >= 310)) {
+            symbolTable.setVariableExtensions("gl_FragSizeEXT",            1, &E_GL_EXT_fragment_invocation_density);
+            symbolTable.setVariableExtensions("gl_FragInvocationCountEXT", 1, &E_GL_EXT_fragment_invocation_density);
+            BuiltInVariable("gl_FragSizeEXT",            EbvFragSizeEXT, symbolTable);
+            BuiltInVariable("gl_FragInvocationCountEXT", EbvFragInvocationCountEXT, symbolTable);
+        }
+
         symbolTable.setVariableExtensions("gl_FragDepthEXT", 1, &E_GL_EXT_frag_depth);
 
         if (profile == EEsProfile && version < 320) {

glslang/MachineIndependent/Versions.cpp

@@ -205,6 +205,7 @@ void TParseVersions::initializeExtensionBehavior()
     extensionBehavior[E_GL_EXT_nonuniform_qualifier]                    = EBhDisable;
     extensionBehavior[E_GL_EXT_samplerless_texture_functions]           = EBhDisable;
     extensionBehavior[E_GL_EXT_scalar_block_layout]                     = EBhDisable;
+    extensionBehavior[E_GL_EXT_fragment_invocation_density]             = EBhDisable;
 
     extensionBehavior[E_GL_EXT_shader_16bit_storage]                    = EBhDisable;
     extensionBehavior[E_GL_EXT_shader_8bit_storage]                     = EBhDisable;
@@ -380,6 +381,7 @@ void TParseVersions::getPreamble(std::string& preamble)
             "#define GL_EXT_shader_8bit_storage 1\n"
             "#define GL_EXT_samplerless_texture_functions 1\n"
             "#define GL_EXT_scalar_block_layout 1\n"
+            "#define GL_EXT_fragment_invocation_density 1\n"
 
             // GL_KHR_shader_subgroup
             "#define GL_KHR_shader_subgroup_basic 1\n"

glslang/MachineIndependent/Versions.h

@@ -167,6 +167,7 @@ const char* const E_GL_EXT_control_flow_attributes          = "GL_EXT_control_fl
 const char* const E_GL_EXT_nonuniform_qualifier             = "GL_EXT_nonuniform_qualifier";
 const char* const E_GL_EXT_samplerless_texture_functions    = "GL_EXT_samplerless_texture_functions";
 const char* const E_GL_EXT_scalar_block_layout              = "GL_EXT_scalar_block_layout";
+const char* const E_GL_EXT_fragment_invocation_density      = "GL_EXT_fragment_invocation_density";
 
 // Arrays of extensions for the above viewportEXTs duplications
 

gtests/Spv.FromFile.cpp

@@ -271,6 +271,10 @@ INSTANTIATE_TEST_CASE_P(
         "spv.flowControl.frag",
         "spv.forLoop.frag",
         "spv.forwardFun.frag",
+        "spv.fragmentDensity.frag",
+        "spv.fragmentDensity.vert",
+        "spv.fragmentDensity-es.frag",
+        "spv.fragmentDensity-neg.frag",
         "spv.fullyCovered.frag",
         "spv.functionCall.frag",
         "spv.functionNestedOpaque.vert",

known_good.json

@@ -12,7 +12,7 @@
       "site" : "github",
       "subrepo" : "KhronosGroup/SPIRV-Headers",
       "subdir" : "External/spirv-tools/external/spirv-headers",
-      "commit" : "a2c529b5dda18838ab4b52f816acfebd774eaab3"
+      "commit" : "282879ca34563020dbe73fd8f7d45bed6755626a"
     }
   ]
 }