Add support for SPV_NV_geometry_shader_passthrough

SPIRV/GLSL.ext.NV.h

@@ -32,11 +32,18 @@ enum Decoration;
 enum Op;
 
 static const int GLSLextNVVersion = 100;
-static const int GLSLextNVRevision = 1;
+static const int GLSLextNVRevision = 2;
 
 //SPV_NV_sample_mask_override_coverage
 const char* const E_SPV_NV_sample_mask_override_coverage = "SPV_NV_sample_mask_override_coverage";
 
 static const Decoration OverrideCoverageNV = static_cast<Decoration>(5248);
 
+
+//SPV_NV_geometry_shader_passthrough
+const char* const E_SPV_NV_geometry_shader_passthrough = "SPV_NV_geometry_shader_passthrough";
+
+static const Decoration PassthroughNV = static_cast<Decoration>(5250);
+
+static const Capability GeometryShaderPassthroughNV = static_cast<Capability>(5251);
 #endif  // #ifndef GLSLextNV_H

SPIRV/GlslangToSpv.cpp

@@ -4738,6 +4738,11 @@ spv::Id TGlslangToSpvTraverser::getSymbolId(const glslang::TIntermSymbol* symbol
             builder.addExtension(spv::E_SPV_NV_sample_mask_override_coverage);
         }
     }
+    if (symbol->getQualifier().layoutPassthrough) {
+        addDecoration(id, spv::PassthroughNV);
+        builder.addCapability(spv::GeometryShaderPassthroughNV);
+        builder.addExtension(spv::E_SPV_NV_geometry_shader_passthrough);
+    }
 #endif
 
     return id;

SPIRV/disassemble.cpp

@@ -481,7 +481,8 @@ void SpirvStream::disassembleInstruction(Id resultId, Id /*typeId*/, Op opCode,
                     extInstSet = GLSLextAMDInst;
 #endif
 #ifdef NV_EXTENSIONS
-                } else if (strcmp(spv::E_SPV_NV_sample_mask_override_coverage, name) == 0) {
+                }else if (strcmp(spv::E_SPV_NV_sample_mask_override_coverage, name) == 0 ||
+                          strcmp(spv::E_SPV_NV_geometry_shader_passthrough, name) == 0) {
                     extInstSet = GLSLextNVInst;
 #endif
                 }
@@ -654,9 +655,12 @@ static const char* GLSLextAMDGetDebugNames(const char* name, unsigned entrypoint
 #ifdef NV_EXTENSIONS
 static const char* GLSLextNVGetDebugNames(const char* name, unsigned entrypoint)
 {
-    if (strcmp(name, spv::E_SPV_NV_sample_mask_override_coverage) == 0) {
+    if (strcmp(name, spv::E_SPV_NV_sample_mask_override_coverage) == 0 ||
+        strcmp(name, spv::E_SPV_NV_geometry_shader_passthrough) == 0) {
         switch (entrypoint) {
         case OverrideCoverageNV:          return "OverrideCoverageNV";
+        case PassthroughNV:               return "PassthroughNV";
+        case GeometryShaderPassthroughNV: return "GeometryShaderPassthroughNV";
         default:                          return "Bad";
         }
     }

SPIRV/doc.cpp

@@ -261,6 +261,7 @@ const char* DecorationString(int decoration)
 #endif
 #ifdef NV_EXTENSIONS
     case 5248: return "OverrideCoverageNV";
+    case 5250: return "PassthroughNV";
 #endif
     }
 }
@@ -818,6 +819,11 @@ const char* CapabilityString(int info)
 
     case 4423: return "SubgroupBallotKHR";
     case 4427: return "DrawParameters";
+
+#ifdef NV_EXTENSIONS
+    case 5251: return "GeometryShaderPassthroughNV";
+#endif
+
     }
 }
 

Test/baseResults/spv.GeometryShaderPassthrough.geom.out

@@ -0,0 +1,46 @@
+spv.GeometryShaderPassthrough.geom
+Warning, version 450 is not yet complete; most version-specific features are present, but some are missing.
+
+// Module Version 10000
+// Generated by (magic number): 80001
+// Id's are bound by 15
+
+                              Capability Geometry
+                              Capability GeometryShaderPassthroughNV
+                              Extension  "SPV_NV_geometry_shader_passthrough"
+               1:             ExtInstImport  "GLSL.std.450"
+                              MemoryModel Logical GLSL450
+                              EntryPoint Geometry 4  "main" 10 14
+                              ExecutionMode 4 Triangles
+                              ExecutionMode 4 Invocations 1
+                              ExecutionMode 4 OutputVertices
+                              Source GLSL 450
+                              SourceExtension  "GL_NV_geometry_shader_passthrough"
+                              Name 4  "main"
+                              Name 8  "gl_PerVertex"
+                              MemberName 8(gl_PerVertex) 0  "gl_Position"
+                              Name 10  ""
+                              Name 12  "Inputs"
+                              MemberName 12(Inputs) 0  "texcoord"
+                              MemberName 12(Inputs) 1  "baseColor"
+                              Name 14  ""
+                              MemberDecorate 8(gl_PerVertex) 0 BuiltIn Position
+                              Decorate 8(gl_PerVertex) Block
+                              Decorate 10 PassthroughNV
+                              Decorate 12(Inputs) Block
+                              Decorate 14 PassthroughNV
+               2:             TypeVoid
+               3:             TypeFunction 2
+               6:             TypeFloat 32
+               7:             TypeVector 6(float) 4
+ 8(gl_PerVertex):             TypeStruct 7(fvec4)
+               9:             TypePointer Input 8(gl_PerVertex)
+              10:      9(ptr) Variable Input
+              11:             TypeVector 6(float) 2
+      12(Inputs):             TypeStruct 11(fvec2) 7(fvec4)
+              13:             TypePointer Input 12(Inputs)
+              14:     13(ptr) Variable Input
+         4(main):           2 Function None 3
+               5:             Label
+                              Return
+                              FunctionEnd

Test/spv.GeometryShaderPassthrough.geom

@@ -0,0 +1,17 @@
+#version 450
+#extension GL_NV_geometry_shader_passthrough : require
+
+layout(triangles) in;
+
+layout(passthrough) in gl_PerVertex {
+    vec4 gl_Position;
+};
+
+layout(passthrough) in Inputs {
+vec2 texcoord;
+vec4 baseColor;
+};
+
+void main()
+{
+}

glslang/Include/Types.h

@@ -599,6 +599,9 @@ public:
         layoutFormat = ElfNone;
 
         layoutPushConstant = false;
+#ifdef NV_EXTENSIONS
+        layoutPassthrough = false;
+#endif
     }
     bool hasLayout() const
     {
@@ -652,6 +655,10 @@ public:
 
     bool layoutPushConstant;
 
+#ifdef NV_EXTENSIONS
+    bool layoutPassthrough;
+#endif
+
     bool hasUniformLayout() const
     {
         return hasMatrix() ||
@@ -1537,6 +1544,12 @@ public:
                 if (qualifier.layoutPushConstant)
                     p += snprintf(p, end - p, "push_constant ");
 
+#ifdef NV_EXTENSIONS
+                if (qualifier.layoutPassthrough)
+                    p += snprintf(p, end - p, "passthrough ");
+#endif
+
+
                 p += snprintf(p, end - p, ") ");
             }
         }

glslang/MachineIndependent/ParseHelper.cpp

@@ -604,7 +604,11 @@ void TParseContext::fixIoArraySize(const TSourceLoc& loc, TType& type)
 void TParseContext::ioArrayCheck(const TSourceLoc& loc, const TType& type, const TString& identifier)
 {
     if (! type.isArray() && ! symbolTable.atBuiltInLevel()) {
-        if (type.getQualifier().isArrayedIo(language))
+        if (type.getQualifier().isArrayedIo(language)
+#ifdef NV_EXTENSIONS
+            && !type.getQualifier().layoutPassthrough
+#endif
+           )
             error(loc, "type must be an array:", type.getStorageQualifierString(), identifier.c_str());
     }
 }
@@ -3459,6 +3463,20 @@ void TParseContext::redeclareBuiltinBlock(const TSourceLoc& loc, TTypeList& newT
     //  - remove unused members
     //  - ensure remaining qualifiers/types match
     TType& type = block->getWritableType();
+
+#ifdef NV_EXTENSIONS
+    // if gl_PerVertex is redeclared for the purpose of passing through "gl_Position"
+    // for passthrough purpose, the redclared block should have the same qualifers as
+    // the current one
+    if (currentBlockQualifier.layoutPassthrough)
+    {
+        type.getQualifier().layoutPassthrough = currentBlockQualifier.layoutPassthrough;
+        type.getQualifier().storage = currentBlockQualifier.storage;
+        type.getQualifier().layoutStream = currentBlockQualifier.layoutStream;
+        type.getQualifier().layoutXfbBuffer = currentBlockQualifier.layoutXfbBuffer;
+    }
+#endif
+
     TTypeList::iterator member = type.getWritableStruct()->begin();
     size_t numOriginalMembersFound = 0;
     while (member != type.getStruct()->end()) {
@@ -3928,6 +3946,14 @@ void TParseContext::setLayoutQualifier(const TSourceLoc& loc, TPublicType& publi
                 publicType.shaderQualifiers.geometry = ElgTriangleStrip;
                 return;
             }
+#ifdef NV_EXTENSIONS
+            if (id == "passthrough") {
+               requireExtensions(loc, 1, &E_SPV_NV_geometry_shader_passthrough, "geometry shader passthrough");
+               publicType.qualifier.layoutPassthrough = true;
+               intermediate.setGeoPassthroughEXT();
+               return;
+            }
+#endif
         } else {
             assert(language == EShLangTessEvaluation);
 
@@ -4328,6 +4354,11 @@ void TParseContext::mergeObjectLayoutQualifiers(TQualifier& dst, const TQualifie
 
         if (src.layoutPushConstant)
             dst.layoutPushConstant = true;
+
+#ifdef NV_EXTENSIONS
+        if (src.layoutPassthrough)
+            dst.layoutPassthrough = true;
+#endif
     }
 }
 

glslang/MachineIndependent/Versions.cpp

@@ -197,6 +197,7 @@ void TParseVersions::initializeExtensionBehavior()
 
 #ifdef NV_EXTENSIONS 
     extensionBehavior[E_GL_NV_sample_mask_override_coverage]         = EBhDisable;
+    extensionBehavior[E_SPV_NV_geometry_shader_passthrough]          = EBhDisable;
 #endif
 
     // AEP
@@ -309,6 +310,7 @@ void TParseVersions::getPreamble(std::string& preamble)
 
 #ifdef NV_EXTENSIONS 
             "#define GL_NV_sample_mask_override_coverage 1\n"
+            "#define GL_NV_geometry_shader_passthrough 1\n"
 #endif
             ;
     }

glslang/MachineIndependent/Versions.h

@@ -144,6 +144,7 @@ const char* const E_GL_AMD_gpu_shader_half_float                = "GL_AMD_gpu_sh
 #endif
 #ifdef NV_EXTENSIONS
 const char* const E_GL_NV_sample_mask_override_coverage = "GL_NV_sample_mask_override_coverage";
+const char* const E_SPV_NV_geometry_shader_passthrough = "GL_NV_geometry_shader_passthrough";
 #endif
 
 // AEP

glslang/MachineIndependent/linkValidate.cpp

@@ -469,9 +469,17 @@ void TIntermediate::finalCheck(TInfoSink& infoSink, bool keepUncalled)
     case EShLangGeometry:
         if (inputPrimitive == ElgNone)
             error(infoSink, "At least one shader must specify an input layout primitive");
-        if (outputPrimitive == ElgNone)
+        if (outputPrimitive == ElgNone
+#ifdef NV_EXTENSIONS
+            && !getGeoPassthroughEXT()
+#endif
+            )
             error(infoSink, "At least one shader must specify an output layout primitive");
-        if (vertices == TQualifier::layoutNotSet)
+        if (vertices == TQualifier::layoutNotSet
+#ifdef NV_EXTENSIONS
+            && !getGeoPassthroughEXT()
+#endif
+           )
             error(infoSink, "At least one shader must specify a layout(max_vertices = value)");
         break;
     case EShLangFragment:

glslang/MachineIndependent/localintermediate.h

@@ -153,6 +153,7 @@ public:
         flattenUniformArrays(false),
 #ifdef NV_EXTENSIONS 
         layoutOverrideCoverage(false),
+        geoPassthroughEXT(false),
 #endif
         useUnknownFormat(false)
     {
@@ -393,6 +394,8 @@ public:
 #ifdef NV_EXTENSIONS 
     void setLayoutOverrideCoverage() { layoutOverrideCoverage = true; }
     bool getLayoutOverrideCoverage() const { return layoutOverrideCoverage; }
+    void setGeoPassthroughEXT() { geoPassthroughEXT = true; }
+    bool getGeoPassthroughEXT() const { return geoPassthroughEXT; }
 #endif
 
 protected:
@@ -457,6 +460,7 @@ protected:
 
 #ifdef NV_EXTENSIONS 
     bool layoutOverrideCoverage;
+    bool geoPassthroughEXT;
 #endif
 
     typedef std::list<TCall> TGraph;

gtests/Spv.FromFile.cpp

@@ -216,6 +216,7 @@ INSTANTIATE_TEST_CASE_P(
         "spv.forwardFun.frag",
         "spv.functionCall.frag",
         "spv.functionSemantics.frag",
+        "spv.GeometryShaderPassthrough.geom",
         "spv.interpOps.frag",
         "spv.int64.frag",
         "spv.layoutNested.vert",