SPV: Fix 'location' inheritance bug.

SPIRV/GlslangToSpv.cpp

@@ -535,8 +535,6 @@ void InheritQualifiers(glslang::TQualifier& child, const glslang::TQualifier& pa
         child.patch = true;
     if (parent.sample)
         child.sample = true;
-
-    child.layoutLocation = parent.layoutLocation;
 }
 
 bool HasNonLayoutQualifiers(const glslang::TQualifier& qualifier)
@@ -1723,10 +1721,14 @@ spv::Id TGlslangToSpvTraverser::convertGlslangToSpvType(const glslang::TType& ty
                     // modify just this child's view of the qualifier
                     glslang::TQualifier subQualifier = glslangType.getQualifier();
                     InheritQualifiers(subQualifier, qualifier);
-                    if (qualifier.hasLocation()) {
+
-                        subQualifier.layoutLocation += locationOffset;
+                    // manually inherit location; it's more complex
+                    if (! subQualifier.hasLocation() && qualifier.hasLocation())
+                        subQualifier.layoutLocation = qualifier.layoutLocation + locationOffset;
+                    if (qualifier.hasLocation())
                         locationOffset += glslangIntermediate->computeTypeLocationSize(glslangType);
-                    }
+
+                    // recurse
                     structFields.push_back(convertGlslangToSpvType(glslangType, explicitLayout, subQualifier));
                 }
             }
@@ -1756,10 +1758,22 @@ spv::Id TGlslangToSpvTraverser::convertGlslangToSpvType(const glslang::TType& ty
                     addMemberDecoration(spvType, member, TranslatePrecisionDecoration(glslangType));
                     addMemberDecoration(spvType, member, TranslateInterpolationDecoration(subQualifier));
                     addMemberDecoration(spvType, member, TranslateInvariantDecoration(subQualifier));
-                    if (qualifier.hasLocation()) {
+
-                        builder.addMemberDecoration(spvType, member, spv::DecorationLocation, qualifier.layoutLocation + locationOffset);
+                    // compute location decoration; tricky based on whether inheritance is at play
+                    // TODO: This algorithm (and it's cousin above doing almost the same thing) should
+                    //       probably move to the linker stage of the front end proper, and just have the
+                    //       answer sitting already distributed throughout the individual member locations.
+                    int location = -1;                // will only decorate if present or inherited
+                    if (subQualifier.hasLocation())   // no inheritance, or override of inheritance
+                        location = subQualifier.layoutLocation;
+                    else if (qualifier.hasLocation()) // inheritance
+                        location = qualifier.layoutLocation + locationOffset;
+                    if (qualifier.hasLocation())      // track for upcoming inheritance
                         locationOffset += glslangIntermediate->computeTypeLocationSize(glslangType);
-                    }
+                    if (location >= 0)
+                        builder.addMemberDecoration(spvType, member, spv::DecorationLocation, location);
+
+                    // component, XFB, others
                     if (glslangType.getQualifier().hasComponent())
                         builder.addMemberDecoration(spvType, member, spv::DecorationComponent, glslangType.getQualifier().layoutComponent);
                     if (glslangType.getQualifier().hasXfbOffset())

Test/baseResults/spv.430.vert.out

@@ -1,5 +1,5 @@
 spv.430.vert
-Warning, version 430 is not yet complete; most version-specific features are present, but some are missing.
+Warning, version 450 is not yet complete; most version-specific features are present, but some are missing.
 
 
 Linked vertex stage:
@@ -7,14 +7,14 @@ Linked vertex stage:
 
 // Module Version 10000
 // Generated by (magic number): 80001
-// Id's are bound by 63
+// Id's are bound by 66
 
                               Capability Shader
                               Capability ClipDistance
                1:             ExtInstImport  "GLSL.std.450"
                               MemoryModel Logical GLSL450
-                              EntryPoint Vertex 4  "main" 12 23 34 38 41 42 62
+                              EntryPoint Vertex 4  "main" 12 23 34 38 41 42 62 65
-                              Source GLSL 430
+                              Source GLSL 450
                               Name 4  "main"
                               Name 10  "gl_PerVertex"
                               MemberName 10(gl_PerVertex) 0  "gl_ClipDistance"
@@ -42,6 +42,9 @@ Linked vertex stage:
                               MemberName 60(SS) 1  "s"
                               MemberName 60(SS) 2  "c"
                               Name 62  "var"
+                              Name 63  "MS"
+                              MemberName 63(MS) 0  "f"
+                              Name 65  "outMS"
                               MemberDecorate 10(gl_PerVertex) 0 BuiltIn ClipDistance
                               Decorate 10(gl_PerVertex) Block
                               Decorate 34(badorder3) Flat
@@ -72,6 +75,8 @@ Linked vertex stage:
                               MemberDecorate 60(SS) 1 Location 1
                               MemberDecorate 60(SS) 2 Flat
                               MemberDecorate 60(SS) 2 Location 4
+                              MemberDecorate 63(MS) 0 Location 17
+                              Decorate 63(MS) Block
                2:             TypeVoid
                3:             TypeFunction 2
                6:             TypeFloat 32
@@ -121,6 +126,9 @@ Linked vertex stage:
           60(SS):             TypeStruct 19(fvec4) 59(S) 19(fvec4)
               61:             TypePointer Output 60(SS)
          62(var):     61(ptr) Variable Output
+          63(MS):             TypeStruct 6(float)
+              64:             TypePointer Output 63(MS)
+       65(outMS):     64(ptr) Variable Output
          4(main):           2 Function None 3
                5:             Label
               18:     17(ptr) AccessChain 12 14 15

Test/spv.430.vert

@@ -1,4 +1,4 @@
-#version 430 core
+#version 450 core
 
 
 
@@ -34,3 +34,4 @@ layout(binding = 31) uniform sampler2D sampb4;
 struct S { mediump float a; highp uvec2 b; highp vec3 c; };
 struct SS { vec4 b; S s; vec4 c; };
 layout(location = 0) flat out SS var;
+out MS { layout(location = 17) float f; } outMS;

glslang/Include/BaseTypes.h

@@ -71,7 +71,7 @@ enum TStorageQualifier {
     EvqGlobal,        // For globals read/write
     EvqConst,         // User-defined constant values, will be semantically constant and constant folded
     EvqVaryingIn,     // pipeline input, read only, also supercategory for all built-ins not included in this enum (see TBuiltInVariable)
-    EvqVaryingOut,    // pipeline ouput, read/write, also supercategory for all built-ins not included in this enum (see TBuiltInVariable)
+    EvqVaryingOut,    // pipeline output, read/write, also supercategory for all built-ins not included in this enum (see TBuiltInVariable)
     EvqUniform,       // read only, shared with app
     EvqBuffer,        // read/write, shared with app
     EvqShared,        // compute shader's read/write 'shared' qualifier