HLSL: add methods to track user structure in texture return type.

Test/hlsl.texture.struct.frag

+struct s1_t {
+    float  c0;
+    float2 c1;
+    float  c2;
+};
+
+struct s2_t {
+    float  c0;
+    float3 c1;
+};
+
+struct s3_t {
+    float2  c0;
+    float1  c1;
+};
+
+struct s4_t {
+    int  c0;
+    int2 c1;
+    int  c2;
+};
+
+struct s5_t {
+    uint c0;
+    uint c1;
+};
+
+SamplerState g_sSamp;
+Texture2D <s1_t>   g_tTex2s1;
+Texture2D <s2_t>   g_tTex2s2;
+Texture2D <s3_t>   g_tTex2s3;
+Texture2D <s4_t>   g_tTex2s4;
+Texture2D <s5_t>   g_tTex2s5;
+
+Texture2D <s1_t>   g_tTex2s1a; // same type as g_tTex2s1, to test fn signature matching.
+
+// function overloading to test name mangling with textures templatized on structs
+s1_t fn1(Texture2D <s1_t> t1) { return t1 . Sample(g_sSamp, float2(0.6, 0.61)); }
+s2_t fn1(Texture2D <s2_t> t2) { return t2 . Sample(g_sSamp, float2(0.6, 0.61)); }
+
+float4 main() : SV_Target0
+{
+    s1_t s1 = g_tTex2s1 . Sample(g_sSamp, float2(0.1, 0.11));
+    s2_t s2 = g_tTex2s2 . Sample(g_sSamp, float2(0.2, 0.21));
+    s3_t s3 = g_tTex2s3 . Sample(g_sSamp, float2(0.3, 0.31));
+    s4_t s4 = g_tTex2s4 . Sample(g_sSamp, float2(0.4, 0.41));
+    s5_t s5 = g_tTex2s5 . Sample(g_sSamp, float2(0.5, 0.51));
+
+    s1_t r0 = fn1(g_tTex2s1);
+    s2_t r1 = fn1(g_tTex2s2);
+    s1_t r2 = fn1(g_tTex2s1a);
+
+    return 0;
+}
+

Test/hlsl.texture.subvec4.frag

@@ -11,7 +11,7 @@ Texture2D <float4> g_tTex2df4;
 
 SamplerState g_sSamp;
 
-float4 main()
+float4 main() : SV_Target0
 {
     uint MipLevel;
     uint WidthU;

glslang/Include/Types.h

@@ -80,7 +80,19 @@ struct TSampler {   // misnomer now; includes images, textures without sampler,
     bool   combined : 1;  // true means texture is combined with a sampler, false means texture with no sampler
     bool    sampler : 1;  // true means a pure sampler, other fields should be clear()
     bool   external : 1;  // GL_OES_EGL_image_external
-    unsigned int vectorSize : 3;  // return vector size.  TODO: support arbitrary types.
+    unsigned int vectorSize : 3;  // vector return type size.
+
+    // Some languages support structures as sample results.  Storing the whole structure in the
+    // TSampler is too large, so there is an index to a separate table.
+    static const unsigned structReturnIndexBits = 4;                        // number of index bits to use.
+    static const unsigned structReturnSlots = (1<<structReturnIndexBits)-1; // number of valid values
+    static const unsigned noReturnStruct = structReturnSlots;               // value if no return struct type.
+
+    // Index into a language specific table of texture return structures.
+    unsigned int structReturnIndex : structReturnIndexBits;
+
+    // Encapsulate getting members' vector sizes packed into the vectorSize bitfield.
+    unsigned int getVectorSize() const { return vectorSize; }
 
     bool isImage()       const { return image && dim != EsdSubpass; }
     bool isSubpass()     const { return dim == EsdSubpass; }
@@ -90,6 +102,7 @@ struct TSampler {   // misnomer now; includes images, textures without sampler,
     bool isShadow()      const { return shadow; }
     bool isArrayed()     const { return arrayed; }
     bool isMultiSample() const { return ms; }
+    bool hasReturnStruct() const { return structReturnIndex != noReturnStruct; }
 
     void clear()
     {
@@ -102,6 +115,9 @@ struct TSampler {   // misnomer now; includes images, textures without sampler,
         combined = false;
         sampler = false;
         external = false;
+        structReturnIndex = noReturnStruct;
+
+        // by default, returns a single vec4;
         vectorSize = 4;
     }
 
@@ -160,16 +176,17 @@ struct TSampler {   // misnomer now; includes images, textures without sampler,
 
     bool operator==(const TSampler& right) const
     {
-        return type == right.type &&
-                dim == right.dim &&
-            arrayed == right.arrayed &&
-             shadow == right.shadow &&
-                 ms == right.ms &&
-              image == right.image &&
-           combined == right.combined &&
-            sampler == right.sampler &&
-           external == right.external &&
-         vectorSize == right.vectorSize;
+        return      type == right.type &&
+                     dim == right.dim &&
+                 arrayed == right.arrayed &&
+                  shadow == right.shadow &&
+                      ms == right.ms &&
+                   image == right.image &&
+                combined == right.combined &&
+                 sampler == right.sampler &&
+                external == right.external &&
+              vectorSize == right.vectorSize &&
+       structReturnIndex == right.structReturnIndex;            
     }
 
     bool operator!=(const TSampler& right) const

glslang/MachineIndependent/SymbolTable.cpp

@@ -104,11 +104,20 @@ void TType::buildMangledName(TString& mangledName) const
         default: break; // some compilers want this
         }
 
-        switch (sampler.vectorSize) {
-        case 1: mangledName += "1"; break;
-        case 2: mangledName += "2"; break;
-        case 3: mangledName += "3"; break;
-        case 4: break; // default to prior name mangle behavior
+        if (sampler.hasReturnStruct()) {
+            // Name mangle for sampler return struct uses struct table index.
+            mangledName += "-tx-struct";
+
+            char text[16]; // plenty enough space for the small integers.
+            snprintf(text, sizeof(text), "%d-", sampler.structReturnIndex);
+            mangledName += text;
+        } else {
+            switch (sampler.getVectorSize()) {
+            case 1: mangledName += "1"; break;
+            case 2: mangledName += "2"; break;
+            case 3: mangledName += "3"; break;
+            case 4: break; // default to prior name mangle behavior
+            }
         }
 
         if (sampler.ms)

gtests/Hlsl.FromFile.cpp

@@ -291,6 +291,7 @@ INSTANTIATE_TEST_CASE_P(
         {"hlsl.structIoFourWay.frag", "main"},
         {"hlsl.structStructName.frag", "main"},
         {"hlsl.synthesizeInput.frag", "main"},
+        {"hlsl.texture.struct.frag", "main"},
         {"hlsl.texture.subvec4.frag", "main"},
         {"hlsl.this.frag", "main"},
         {"hlsl.intrinsics.vert", "VertexShaderFunction"},

hlsl/hlslGrammar.cpp

@@ -1189,7 +1189,13 @@ bool HlslGrammar::acceptTextureType(TType& type)
 
         const TBasicType basicRetType = txType.getBasicType() ;
 
-        if (basicRetType != EbtFloat && basicRetType != EbtUint && basicRetType != EbtInt) {
+        switch (basicRetType) {
+        case EbtFloat:
+        case EbtUint:
+        case EbtInt:
+        case EbtStruct:
+            break;
+        default:
             unimplemented("basic type in texture");
             return false;
         }
@@ -1206,8 +1212,8 @@ bool HlslGrammar::acceptTextureType(TType& type)
             return false;
         }
 
-        if (!txType.isScalar() && !txType.isVector()) {
-            expected("scalar or vector type");
+        if (!txType.isScalar() && !txType.isVector() && !txType.isStruct()) {
+            expected("scalar, vector, or struct type");
             return false;
         }
 
@@ -1244,20 +1250,24 @@ bool HlslGrammar::acceptTextureType(TType& type)
     if (image || dim == EsdBuffer)
         format = parseContext.getLayoutFromTxType(token.loc, txType);
 
+    const TBasicType txBasicType = txType.isStruct() ? (*txType.getStruct())[0].type->getBasicType()
+        : txType.getBasicType();
+
     // Non-image Buffers are combined
     if (dim == EsdBuffer && !image) {
         sampler.set(txType.getBasicType(), dim, array);
     } else {
         // DX10 textures are separated.  TODO: DX9.
         if (image) {
-            sampler.setImage(txType.getBasicType(), dim, array, shadow, ms);
+            sampler.setImage(txBasicType, dim, array, shadow, ms);
         } else {
-            sampler.setTexture(txType.getBasicType(), dim, array, shadow, ms);
+            sampler.setTexture(txBasicType, dim, array, shadow, ms);
         }
     }
 
-    // Remember the declared vector size.
-    sampler.vectorSize = txType.getVectorSize();
+    // Remember the declared return type.  Function returns false on error.
+    if (!parseContext.setTextureReturnType(sampler, txType, token.loc))
+        return false;
 
     // Force uncombined, if necessary
     if (!combined)

hlsl/hlslParseHelper.h

@@ -213,6 +213,12 @@ public:
     // Share struct buffer deep types
     void shareStructBufferType(TType&);
 
+    // Set texture return type of the given sampler.  Returns success (not all types are valid).
+    bool setTextureReturnType(TSampler& sampler, const TType& retType, const TSourceLoc& loc);
+
+    // Obtain the sampler return type of the given sampler in retType.
+    void getTextureReturnType(const TSampler& sampler, TType& retType) const;
+
 protected:
     struct TFlattenData {
         TFlattenData() : nextBinding(TQualifier::layoutBindingEnd),
@@ -388,6 +394,10 @@ protected:
 
     // Structuredbuffer shared types.  Typically there are only a few.
     TVector<TType*> structBufferTypes;
+
+    // This tracks texture sample user structure return types.  Only a limited number are supported, as
+    // may fit in TSampler::structReturnIndex.
+    TVector<TTypeList*> textureReturnStruct;
     
     TMap<TString, bool> structBufferCounter;