added support for push_constant layout

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2187433003

Committed: https://skia.googlesource.com/skia/+/fa5f65ac61fd525029aa9dab161ffe4896c10f6d
Review-Url: https://codereview.chromium.org/2187433003

9 files changed, 380 insertions, 110 deletions

diff --git a/gn/tests.gni b/gn/tests.gni
index 2cf9d330fc..98980ec0f6 100644
--- a/gn/tests.gni
+++ b/gn/tests.gni
@@ -204,6 +204,7 @@ tests_sources = [
   "$_tests/SkSharedMutexTest.cpp",
   "$_tests/SkSLErrorTest.cpp",
   "$_tests/SkSLGLSLTest.cpp",
+  "$_tests/SkSLMemoryLayoutTest.cpp",
   "$_tests/SmallAllocatorTest.cpp",
   "$_tests/SortTest.cpp",
   "$_tests/SpecialImageTest.cpp",
diff --git a/src/sksl/SkSLMemoryLayout.h b/src/sksl/SkSLMemoryLayout.h
new file mode 100644
index 0000000000..95a292f9d9
--- /dev/null
+++ b/src/sksl/SkSLMemoryLayout.h
@@ -0,0 +1,128 @@
+/*
+ * Copyright 2016 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+ 
+#ifndef SKIASL_MEMORYLAYOUT
+#define SKIASL_MEMORYLAYOUT
+
+#include "ir/SkSLType.h"
+
+namespace SkSL {
+
+class MemoryLayout {
+public:
+    enum Standard {
+        k140_Standard,
+        k430_Standard
+    };
+
+    MemoryLayout(Standard std) 
+    : fStd(std) {}
+
+    static size_t vector_alignment(size_t componentSize, int columns) {
+        return componentSize * (columns + columns % 2);
+    }
+
+    /** 
+     * Rounds up to the nearest multiple of 16 if in std140, otherwise returns the parameter
+     * unchanged (std140 requires various things to be rounded up to the nearest multiple of 16,
+     * std430 does not).
+     */
+    size_t roundUpIfNeeded(size_t raw) const {
+        switch (fStd) {
+            case k140_Standard: return (raw + 15) & ~15;
+            case k430_Standard: return raw;
+        }
+        ABORT("unreachable");
+    }
+
+    /**
+     * Returns a type's required alignment when used as a standalone variable.
+     */
+    size_t alignment(const Type& type) const {
+        // See OpenGL Spec 7.6.2.2 Standard Uniform Block Layout
+        switch (type.kind()) {
+            case Type::kScalar_Kind:
+                return this->size(type);
+            case Type::kVector_Kind:
+                return vector_alignment(this->size(type.componentType()), type.columns());
+            case Type::kMatrix_Kind:
+                return this->roundUpIfNeeded(vector_alignment(this->size(type.componentType()), 
+                                                              type.rows()));
+            case Type::kArray_Kind:
+                return this->roundUpIfNeeded(this->alignment(type.componentType()));
+            case Type::kStruct_Kind: {
+                size_t result = 0;
+                for (const auto& f : type.fields()) {
+                    size_t alignment = this->alignment(*f.fType);
+                    if (alignment > result) {
+                        result = alignment;
+                    }
+                }
+                return this->roundUpIfNeeded(result);
+            }
+            default:
+                ABORT(("cannot determine size of type " + type.name()).c_str());
+        }
+    }
+
+    /**
+     * For matrices and arrays, returns the number of bytes from the start of one entry (row, in
+     * the case of matrices) to the start of the next.
+     */
+    size_t stride(const Type& type) const {
+        switch (type.kind()) {
+            case Type::kMatrix_Kind: // fall through
+            case Type::kArray_Kind:
+                return this->alignment(type);
+            default:
+                ABORT("type does not have a stride");
+        }
+    }
+
+    /**
+     * Returns the size of a type in bytes.
+     */
+    size_t size(const Type& type) const {
+        switch (type.kind()) {
+            case Type::kScalar_Kind:
+                if (type.name() == "bool") {
+                    return 1;
+                }
+                // FIXME need to take precision into account, once we figure out how we want to
+                // handle it...
+                return 4;
+            case Type::kVector_Kind:
+                return type.columns() * this->size(type.componentType());
+            case Type::kMatrix_Kind: // fall through
+            case Type::kArray_Kind:
+                return type.columns() * this->stride(type);
+            case Type::kStruct_Kind: {
+                size_t total = 0;
+                for (const auto& f : type.fields()) {
+                    size_t alignment = this->alignment(*f.fType);
+                    if (total % alignment != 0) {
+                        total += alignment - total % alignment;
+                    }
+                    ASSERT(total % alignment == 0);
+                    total += this->size(*f.fType);
+                }
+                size_t alignment = this->alignment(type);
+                ASSERT(!type.fields().size() || 
+                       (0 == alignment % this->alignment(*type.fields()[0].fType)));
+                return (total + alignment - 1) & ~(alignment - 1);
+            }
+            default:
+                ABORT(("cannot determine size of type " + type.name()).c_str());
+        }
+    }
+
+    const Standard fStd;
+};
+
+} // namespace
+
+#endif
diff --git a/src/sksl/SkSLParser.cpp b/src/sksl/SkSLParser.cpp
index 58ec750168..80ef870a48 100644
--- a/src/sksl/SkSLParser.cpp
+++ b/src/sksl/SkSLParser.cpp
@@ -535,8 +535,7 @@ int Parser::layoutInt() {
     return -1;
 }
 
-/* LAYOUT LPAREN IDENTIFIER EQ INT_LITERAL (COMMA IDENTIFIER EQ INT_LITERAL)*
-   RPAREN */
+/* LAYOUT LPAREN IDENTIFIER (EQ INT_LITERAL)? (COMMA IDENTIFIER (EQ INT_LITERAL)?)* RPAREN */
 ASTLayout Parser::layout() {
     int location = -1;
     int binding = -1;
@@ -548,11 +547,13 @@ ASTLayout Parser::layout() {
     bool overrideCoverage = false;
     bool blendSupportAllEquations = false;
     ASTLayout::Format format = ASTLayout::Format::kUnspecified;
+    bool pushConstant = false;
     if (this->peek().fKind == Token::LAYOUT) {
         this->nextToken();
         if (!this->expect(Token::LPAREN, "'('")) {
             return ASTLayout(location, binding, index, set, builtin, inputAttachmentIndex,
-                             originUpperLeft, overrideCoverage, blendSupportAllEquations, format);
+                             originUpperLeft, overrideCoverage, blendSupportAllEquations, format,
+                             pushConstant);
         }
         for (;;) {
             Token t = this->nextToken();
@@ -576,6 +577,8 @@ ASTLayout Parser::layout() {
                 blendSupportAllEquations = true;
             } else if (ASTLayout::ReadFormat(t.fText, &format)) {
                // AST::ReadFormat stored the result in 'format'.
+            } else if (t.fText == "push_constant") {
+                pushConstant = true;
             } else {
                 this->error(t.fPosition, ("'" + t.fText +
                                           "' is not a valid layout qualifier").c_str());
@@ -590,7 +593,7 @@ ASTLayout Parser::layout() {
         }
     }
     return ASTLayout(location, binding, index, set, builtin, inputAttachmentIndex, originUpperLeft,
-                     overrideCoverage, blendSupportAllEquations, format);
+                     overrideCoverage, blendSupportAllEquations, format, pushConstant);
 }
 
 /* layout? (UNIFORM | CONST | IN | OUT | INOUT | LOWP | MEDIUMP | HIGHP | FLAT | NOPERSPECTIVE)* */
diff --git a/src/sksl/SkSLSPIRVCodeGenerator.cpp b/src/sksl/SkSLSPIRVCodeGenerator.cpp
index 300d3c5d66..ecde11509d 100644
--- a/src/sksl/SkSLSPIRVCodeGenerator.cpp
+++ b/src/sksl/SkSLSPIRVCodeGenerator.cpp
@@ -975,13 +975,13 @@ SpvId SPIRVCodeGenerator::nextId() {
     return fIdCount++;
 }
 
-void SPIRVCodeGenerator::writeStruct(const Type& type, SpvId resultId) {
+void SPIRVCodeGenerator::writeStruct(const Type& type, const MemoryLayout& layout, SpvId resultId) {
     this->writeInstruction(SpvOpName, resultId, type.name().c_str(), fNameBuffer);
     // go ahead and write all of the field types, so we don't inadvertently write them while we're
     // in the middle of writing the struct instruction
     std::vector<SpvId> types;
     for (const auto& f : type.fields()) {
-        types.push_back(this->getType(*f.fType));
+        types.push_back(this->getType(*f.fType, layout));
     }
     this->writeOpCode(SpvOpTypeStruct, 2 + (int32_t) types.size(), fConstantBuffer);
     this->writeWord(resultId, fConstantBuffer);
@@ -990,8 +990,8 @@ void SPIRVCodeGenerator::writeStruct(const Type& type, SpvId resultId) {
     }
     size_t offset = 0;
     for (int32_t i = 0; i < (int32_t) type.fields().size(); i++) {
-        size_t size = type.fields()[i].fType->size();
-        size_t alignment = type.fields()[i].fType->alignment();
+        size_t size = layout.size(*type.fields()[i].fType);
+        size_t alignment = layout.alignment(*type.fields()[i].fType);
         size_t mod = offset % alignment;
         if (mod != 0) {
             offset += alignment - mod;
@@ -1007,7 +1007,8 @@ void SPIRVCodeGenerator::writeStruct(const Type& type, SpvId resultId) {
             this->writeInstruction(SpvOpMemberDecorate, resultId, i, SpvDecorationColMajor,
                                    fDecorationBuffer);
             this->writeInstruction(SpvOpMemberDecorate, resultId, i, SpvDecorationMatrixStride,
-                                   (SpvId) type.fields()[i].fType->stride(), fDecorationBuffer);
+                                   (SpvId) layout.stride(*type.fields()[i].fType),
+                                   fDecorationBuffer);
         }
         offset += size;
         Type::Kind kind = type.fields()[i].fType->kind();
@@ -1018,7 +1019,12 @@ void SPIRVCodeGenerator::writeStruct(const Type& type, SpvId resultId) {
 }
 
 SpvId SPIRVCodeGenerator::getType(const Type& type) {
-    auto entry = fTypeMap.find(type.name());
+    return this->getType(type, fDefaultLayout);
+}
+
+SpvId SPIRVCodeGenerator::getType(const Type& type, const MemoryLayout& layout) {
+    SkString key = type.name() + to_string((int) layout.fStd);
+    auto entry = fTypeMap.find(key);
     if (entry == fTypeMap.end()) {
         SpvId result = this->nextId();
         switch (type.kind()) {
@@ -1039,29 +1045,31 @@ SpvId SPIRVCodeGenerator::getType(const Type& type) {
                 break;
             case Type::kVector_Kind:
                 this->writeInstruction(SpvOpTypeVector, result,
-                                       this->getType(type.componentType()),
+                                       this->getType(type.componentType(), layout),
                                        type.columns(), fConstantBuffer);
                 break;
             case Type::kMatrix_Kind:
                 this->writeInstruction(SpvOpTypeMatrix, result,
-                                       this->getType(index_type(fContext, type)),
+                                       this->getType(index_type(fContext, type), layout),
                                        type.columns(), fConstantBuffer);
                 break;
             case Type::kStruct_Kind:
-                this->writeStruct(type, result);
+                this->writeStruct(type, layout, result);
                 break;
             case Type::kArray_Kind: {
                 if (type.columns() > 0) {
                     IntLiteral count(fContext, Position(), type.columns());
                     this->writeInstruction(SpvOpTypeArray, result,
-                                           this->getType(type.componentType()),
+                                           this->getType(type.componentType(), layout),
                                            this->writeIntLiteral(count), fConstantBuffer);
                     this->writeInstruction(SpvOpDecorate, result, SpvDecorationArrayStride,
-                                           (int32_t) type.stride(), fDecorationBuffer);
+                                           (int32_t) layout.stride(type), 
+                                           fDecorationBuffer);
                 } else {
                     ABORT("runtime-sized arrays are not yet supported");
                     this->writeInstruction(SpvOpTypeRuntimeArray, result,
-                                           this->getType(type.componentType()), fConstantBuffer);
+                                           this->getType(type.componentType(), layout),
+                                           fConstantBuffer);
                 }
                 break;
             }
@@ -1070,7 +1078,8 @@ SpvId SPIRVCodeGenerator::getType(const Type& type) {
                 if (SpvDimSubpassData != type.dimensions()) {
                     image = this->nextId();
                 }
-                this->writeInstruction(SpvOpTypeImage, image, this->getType(*fContext.fFloat_Type),
+                this->writeInstruction(SpvOpTypeImage, image,
+                                       this->getType(*fContext.fFloat_Type, layout),
                                        type.dimensions(), type.isDepth(), type.isArrayed(),
                                        type.isMultisampled(), type.isSampled() ? 1 : 2,
                                        SpvImageFormatUnknown, fConstantBuffer);
@@ -1086,7 +1095,7 @@ SpvId SPIRVCodeGenerator::getType(const Type& type) {
                     ABORT("invalid type: %s", type.description().c_str());
                 }
         }
-        fTypeMap[type.name()] = result;
+        fTypeMap[key] = result;
         return result;
     }
     return entry->second;
@@ -1149,9 +1158,13 @@ SpvId SPIRVCodeGenerator::getFunctionType(const FunctionDeclaration& function) {
     return entry->second;
 }
 
-SpvId SPIRVCodeGenerator::getPointerType(const Type& type,
+SpvId SPIRVCodeGenerator::getPointerType(const Type& type, SpvStorageClass_ storageClass) {
+    return this->getPointerType(type, fDefaultLayout, storageClass);
+}
+
+SpvId SPIRVCodeGenerator::getPointerType(const Type& type, const MemoryLayout& layout,
                                          SpvStorageClass_ storageClass) {
-    SkString key = type.description() + "*" + to_string(storageClass);
+    SkString key = type.description() + "*" + to_string(layout.fStd) + to_string(storageClass);
     auto entry = fTypeMap.find(key);
     if (entry == fTypeMap.end()) {
         SpvId result = this->nextId();
@@ -1590,10 +1603,15 @@ SpvId SPIRVCodeGenerator::writeConstructor(const Constructor& c, SkWStream& out)
 
 SpvStorageClass_ get_storage_class(const Modifiers& modifiers) {
     if (modifiers.fFlags & Modifiers::kIn_Flag) {
+        ASSERT(!modifiers.fLayout.fPushConstant);
         return SpvStorageClassInput;
     } else if (modifiers.fFlags & Modifiers::kOut_Flag) {
+        ASSERT(!modifiers.fLayout.fPushConstant);
         return SpvStorageClassOutput;
     } else if (modifiers.fFlags & Modifiers::kUniform_Flag) {
+        if (modifiers.fLayout.fPushConstant) {
+            return SpvStorageClassPushConstant;
+        }
         return SpvStorageClassUniform;
     } else {
         return SpvStorageClassFunction;
@@ -2404,7 +2422,10 @@ void SPIRVCodeGenerator::writeLayout(const Layout& layout, SpvId target, int mem
 }
 
 SpvId SPIRVCodeGenerator::writeInterfaceBlock(const InterfaceBlock& intf) {
-    SpvId type = this->getType(intf.fVariable.fType);
+    MemoryLayout layout = intf.fVariable.fModifiers.fLayout.fPushConstant ?
+                          MemoryLayout(MemoryLayout::k430_Standard) :
+                          fDefaultLayout;
+    SpvId type = this->getType(intf.fVariable.fType, layout);
     SpvId result = this->nextId();
     this->writeInstruction(SpvOpDecorate, type, SpvDecorationBlock, fDecorationBuffer);
     SpvStorageClass_ storageClass = get_storage_class(intf.fVariable.fModifiers);
@@ -2460,7 +2481,7 @@ void SPIRVCodeGenerator::writeGlobalVars(Program::Kind kind, const VarDeclaratio
             this->writeInstruction(SpvOpMemberDecorate, id, (SpvId) i, SpvDecorationColMajor,
                                    fDecorationBuffer);
             this->writeInstruction(SpvOpMemberDecorate, id, (SpvId) i, SpvDecorationMatrixStride,
-                                   (SpvId) var->fType.stride(), fDecorationBuffer);
+                                   (SpvId) fDefaultLayout.stride(var->fType), fDecorationBuffer);
         }
         if (varDecl.fValue) {
             ASSERT(!fCurrentBlock);
diff --git a/src/sksl/SkSLSPIRVCodeGenerator.h b/src/sksl/SkSLSPIRVCodeGenerator.h
index b79194500a..c885ffc3ff 100644
--- a/src/sksl/SkSLSPIRVCodeGenerator.h
+++ b/src/sksl/SkSLSPIRVCodeGenerator.h
@@ -14,6 +14,7 @@
 
 #include "SkStream.h"
 #include "SkSLCodeGenerator.h"
+#include "SkSLMemoryLayout.h"
 #include "ir/SkSLBinaryExpression.h"
 #include "ir/SkSLBoolLiteral.h"
 #include "ir/SkSLConstructor.h"
@@ -63,6 +64,7 @@ public:
 
     SPIRVCodeGenerator(const Context* context)
     : fContext(*context)
+    , fDefaultLayout(MemoryLayout::k140_Standard)
     , fCapabilities(1 << SpvCapabilityShader)
     , fIdCount(1)
     , fBoolTrue(0)
@@ -94,17 +96,22 @@ private:
 
     SpvId getType(const Type& type);
 
+    SpvId getType(const Type& type, const MemoryLayout& layout);
+
     SpvId getFunctionType(const FunctionDeclaration& function);
 
     SpvId getPointerType(const Type& type, SpvStorageClass_ storageClass);
 
+    SpvId getPointerType(const Type& type, const MemoryLayout& layout, 
+                         SpvStorageClass_ storageClass);
+
     std::vector<SpvId> getAccessChain(const Expression& expr, SkWStream& out);
 
     void writeLayout(const Layout& layout, SpvId target);
 
     void writeLayout(const Layout& layout, SpvId target, int member);
 
-    void writeStruct(const Type& type, SpvId resultId);
+    void writeStruct(const Type& type, const MemoryLayout& layout, SpvId resultId);
 
     void writeProgramElement(const ProgramElement& pe, SkWStream& out);
 
@@ -230,6 +237,7 @@ private:
                           SkWStream& out);
 
     const Context& fContext;
+    const MemoryLayout fDefaultLayout;
 
     uint64_t fCapabilities;
     SpvId fIdCount;
diff --git a/src/sksl/ast/SkSLASTLayout.h b/src/sksl/ast/SkSLASTLayout.h
index a77e8388ed..4c36af46a1 100644
--- a/src/sksl/ast/SkSLASTLayout.h
+++ b/src/sksl/ast/SkSLASTLayout.h
@@ -80,7 +80,7 @@ struct ASTLayout : public ASTNode {
     // For int parameters, a -1 means no value
     ASTLayout(int location, int binding, int index, int set, int builtin, int inputAttachmentIndex,
               bool originUpperLeft, bool overrideCoverage, bool blendSupportAllEquations,
-              Format format)
+              Format format, bool pushConstant)
     : fLocation(location)
     , fBinding(binding)
     , fIndex(index)
@@ -90,7 +90,8 @@ struct ASTLayout : public ASTNode {
     , fOriginUpperLeft(originUpperLeft)
     , fOverrideCoverage(overrideCoverage)
     , fBlendSupportAllEquations(blendSupportAllEquations)
-    , fFormat(format) {}
+    , fFormat(format)
+    , fPushConstant(pushConstant) {}
 
     SkString description() const {
         SkString result;
@@ -135,6 +136,10 @@ struct ASTLayout : public ASTNode {
             result += separator + FormatToStr(fFormat);
             separator = ", ";
         }
+        if (fPushConstant) {
+            result += separator + "push_constant";
+            separator = ", ";
+        }
         if (result.size() > 0) {
             result = "layout (" + result + ")";
         }
@@ -151,6 +156,7 @@ struct ASTLayout : public ASTNode {
     const bool fOverrideCoverage;
     const bool fBlendSupportAllEquations;
     const Format fFormat;
+    const bool fPushConstant;
 };
 
 } // namespace
diff --git a/src/sksl/ir/SkSLLayout.h b/src/sksl/ir/SkSLLayout.h
index c5753e010c..f433614da9 100644
--- a/src/sksl/ir/SkSLLayout.h
+++ b/src/sksl/ir/SkSLLayout.h
@@ -26,11 +26,12 @@ struct Layout {
     , fOriginUpperLeft(layout.fOriginUpperLeft)
     , fOverrideCoverage(layout.fOverrideCoverage)
     , fBlendSupportAllEquations(layout.fBlendSupportAllEquations)
-    , fFormat(layout.fFormat) {}
+    , fFormat(layout.fFormat)
+    , fPushConstant(layout.fPushConstant) {}
 
     Layout(int location, int binding, int index, int set, int builtin, int inputAttachmentIndex,
            bool originUpperLeft, bool overrideCoverage, bool blendSupportAllEquations,
-           ASTLayout::Format format)
+           ASTLayout::Format format, bool pushconstant)
     : fLocation(location)
     , fBinding(binding)
     , fIndex(index)
@@ -40,7 +41,8 @@ struct Layout {
     , fOriginUpperLeft(originUpperLeft)
     , fOverrideCoverage(overrideCoverage)
     , fBlendSupportAllEquations(blendSupportAllEquations)
-    , fFormat(format) {}
+    , fFormat(format)
+    , fPushConstant(pushconstant) {}
 
     Layout()
     : fLocation(-1)
@@ -52,7 +54,8 @@ struct Layout {
     , fOriginUpperLeft(false)
     , fOverrideCoverage(false)
     , fBlendSupportAllEquations(false)
-    , fFormat(ASTLayout::Format::kUnspecified) {}
+    , fFormat(ASTLayout::Format::kUnspecified)
+    , fPushConstant(false) {}
 
     SkString description() const {
         SkString result;
@@ -97,6 +100,10 @@ struct Layout {
             result += separator + ASTLayout::FormatToStr(fFormat);
             separator = ", ";
         }
+        if (fPushConstant) {
+            result += separator + "push_constant";
+            separator = ", ";
+        }
         if (result.size() > 0) {
             result = "layout (" + result + ")";
         }
@@ -134,6 +141,7 @@ struct Layout {
     bool fOverrideCoverage;
     bool fBlendSupportAllEquations;
     ASTLayout::Format fFormat;
+    bool fPushConstant;
 };
 
 } // namespace
diff --git a/src/sksl/ir/SkSLType.h b/src/sksl/ir/SkSLType.h
index 81ec13ab44..a4632061ae 100644
--- a/src/sksl/ir/SkSLType.h
+++ b/src/sksl/ir/SkSLType.h
@@ -238,87 +238,6 @@ public:
         return fIsSampled;
     }
 
-    static size_t vector_alignment(size_t componentSize, int columns) {
-        return componentSize * (columns + columns % 2);
-    }
-
-    /**
-     * Returns the type's required alignment (when putting this type into a struct, the offset must
-     * be a multiple of the alignment).
-     */
-    size_t alignment() const {
-        // See OpenGL Spec 7.6.2.2 Standard Uniform Block Layout
-        switch (fTypeKind) {
-            case kScalar_Kind:
-                return this->size();
-            case kVector_Kind:
-                return vector_alignment(fComponentType->size(), fColumns);
-            case kMatrix_Kind:
-                return (vector_alignment(fComponentType->size(), fRows) + 15) & ~15;
-            case kArray_Kind:
-                // round up to next multiple of 16
-                return (fComponentType->alignment() + 15) & ~15;
-            case kStruct_Kind: {
-                size_t result = 16;
-                for (size_t i = 0; i < fFields.size(); i++) {
-                    size_t alignment = fFields[i].fType->alignment();
-                    if (alignment > result) {
-                        result = alignment;
-                    }
-                }
-            }
-            default:
-                ABORT(("cannot determine size of type " + fName).c_str());
-        }
-    }
-
-    /**
-     * For matrices and arrays, returns the number of bytes from the start of one entry (row, in
-     * the case of matrices) to the start of the next.
-     */
-    size_t stride() const {
-        switch (fTypeKind) {
-            case kMatrix_Kind: // fall through
-            case kArray_Kind:
-                return this->alignment();
-            default:
-                ABORT("type does not have a stride");
-        }
-    }
-
-    /**
-     * Returns the size of this type in bytes.
-     */
-    size_t size() const {
-        switch (fTypeKind) {
-            case kScalar_Kind:
-                // FIXME need to take precision into account, once we figure out how we want to
-                // handle it...
-                return 4;
-            case kVector_Kind:
-                return fColumns * fComponentType->size();
-            case kMatrix_Kind:
-                return vector_alignment(fComponentType->size(), fRows) * fColumns;
-            case kArray_Kind:
-                return fColumns * this->stride();
-            case kStruct_Kind: {
-                size_t total = 0;
-                for (size_t i = 0; i < fFields.size(); i++) {
-                    size_t alignment = fFields[i].fType->alignment();
-                    if (total % alignment != 0) {
-                        total += alignment - total % alignment;
-                    }
-                    ASSERT(false);
-                    ASSERT(total % alignment == 0);
-                    total += fFields[i].fType->size();
-                }
-                return total;
-            }
-            default:
-                ABORT(("cannot determine size of type " + fName).c_str());
-        }
-    }
-
     /**
      * Returns the corresponding vector or matrix type with the specified number of columns and
      * rows.
diff --git a/tests/SkSLMemoryLayoutTest.cpp b/tests/SkSLMemoryLayoutTest.cpp
new file mode 100644
index 0000000000..336d8aa477
--- /dev/null
+++ b/tests/SkSLMemoryLayoutTest.cpp
@@ -0,0 +1,176 @@
+/*
+ * Copyright 2016 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "SkSLContext.h"
+#include "SkSLMemoryLayout.h"
+
+#include "Test.h"
+
+#if SK_SUPPORT_GPU
+
+DEF_TEST(SkSLMemoryLayout140Test, r) {
+    SkSL::Context context;
+    SkSL::MemoryLayout layout(SkSL::MemoryLayout::k140_Standard);
+
+    // basic types
+    REPORTER_ASSERT(r,  4 == layout.size(*context.fFloat_Type));
+    REPORTER_ASSERT(r,  8 == layout.size(*context.fVec2_Type));
+    REPORTER_ASSERT(r, 12 == layout.size(*context.fVec3_Type));
+    REPORTER_ASSERT(r, 16 == layout.size(*context.fVec4_Type));
+    REPORTER_ASSERT(r,  4 == layout.size(*context.fInt_Type));
+    REPORTER_ASSERT(r,  8 == layout.size(*context.fIVec2_Type));
+    REPORTER_ASSERT(r, 12 == layout.size(*context.fIVec3_Type));
+    REPORTER_ASSERT(r, 16 == layout.size(*context.fIVec4_Type));
+    REPORTER_ASSERT(r,  1 == layout.size(*context.fBool_Type));
+    REPORTER_ASSERT(r,  2 == layout.size(*context.fBVec2_Type));
+    REPORTER_ASSERT(r,  3 == layout.size(*context.fBVec3_Type));
+    REPORTER_ASSERT(r,  4 == layout.size(*context.fBVec4_Type));
+    REPORTER_ASSERT(r, 32 == layout.size(*context.fMat2x2_Type));
+    REPORTER_ASSERT(r, 32 == layout.size(*context.fMat2x4_Type));
+    REPORTER_ASSERT(r, 48 == layout.size(*context.fMat3x3_Type));
+    REPORTER_ASSERT(r, 64 == layout.size(*context.fMat4x2_Type));
+    REPORTER_ASSERT(r, 64 == layout.size(*context.fMat4x4_Type));
+    REPORTER_ASSERT(r,  4 == layout.alignment(*context.fFloat_Type));
+    REPORTER_ASSERT(r,  8 == layout.alignment(*context.fVec2_Type));
+    REPORTER_ASSERT(r, 16 == layout.alignment(*context.fVec3_Type));
+    REPORTER_ASSERT(r, 16 == layout.alignment(*context.fVec4_Type));
+    REPORTER_ASSERT(r,  4 == layout.alignment(*context.fInt_Type));
+    REPORTER_ASSERT(r,  8 == layout.alignment(*context.fIVec2_Type));
+    REPORTER_ASSERT(r, 16 == layout.alignment(*context.fIVec3_Type));
+    REPORTER_ASSERT(r, 16 == layout.alignment(*context.fIVec4_Type));
+    REPORTER_ASSERT(r,  1 == layout.alignment(*context.fBool_Type));
+    REPORTER_ASSERT(r,  2 == layout.alignment(*context.fBVec2_Type));
+    REPORTER_ASSERT(r,  4 == layout.alignment(*context.fBVec3_Type));
+    REPORTER_ASSERT(r,  4 == layout.alignment(*context.fBVec4_Type));
+    REPORTER_ASSERT(r, 16 == layout.alignment(*context.fMat2x2_Type));
+    REPORTER_ASSERT(r, 16 == layout.alignment(*context.fMat2x4_Type));
+    REPORTER_ASSERT(r, 16 == layout.alignment(*context.fMat3x3_Type));
+    REPORTER_ASSERT(r, 16 == layout.alignment(*context.fMat4x2_Type));
+    REPORTER_ASSERT(r, 16 == layout.alignment(*context.fMat4x4_Type));
+
+    // struct 1
+    std::vector<SkSL::Type::Field> fields1;
+    fields1.emplace_back(SkSL::Modifiers(), SkString("a"), context.fVec3_Type.get());
+    SkSL::Type s1(SkString("s1"), fields1);
+    REPORTER_ASSERT(r, 16 == layout.size(s1));
+    REPORTER_ASSERT(r, 16 == layout.alignment(s1));
+
+    fields1.emplace_back(SkSL::Modifiers(), SkString("b"), context.fFloat_Type.get());
+    SkSL::Type s2(SkString("s2"), fields1);
+    REPORTER_ASSERT(r, 16 == layout.size(s2));
+    REPORTER_ASSERT(r, 16 == layout.alignment(s2));
+
+    fields1.emplace_back(SkSL::Modifiers(), SkString("c"), context.fBool_Type.get());
+    SkSL::Type s3(SkString("s3"), fields1);
+    REPORTER_ASSERT(r, 32 == layout.size(s3));
+    REPORTER_ASSERT(r, 16 == layout.alignment(s3));
+
+    // struct 2
+    std::vector<SkSL::Type::Field> fields2;
+    fields2.emplace_back(SkSL::Modifiers(), SkString("a"), context.fInt_Type.get());
+    SkSL::Type s4(SkString("s4"), fields2);
+    REPORTER_ASSERT(r, 16 == layout.size(s4));
+    REPORTER_ASSERT(r, 16 == layout.alignment(s4));
+
+    fields2.emplace_back(SkSL::Modifiers(), SkString("b"), context.fVec3_Type.get());
+    SkSL::Type s5(SkString("s5"), fields2);
+    REPORTER_ASSERT(r, 32 == layout.size(s5));
+    REPORTER_ASSERT(r, 16 == layout.alignment(s5));
+
+    // arrays
+    SkSL::Type array1(SkString("float[4]"), SkSL::Type::kArray_Kind, *context.fFloat_Type, 4);
+    REPORTER_ASSERT(r, 64 == layout.size(array1));
+    REPORTER_ASSERT(r, 16 == layout.alignment(array1));
+    REPORTER_ASSERT(r, 16 == layout.stride(array1));
+
+    SkSL::Type array2(SkString("vec4[4]"), SkSL::Type::kArray_Kind, *context.fVec4_Type, 4);
+    REPORTER_ASSERT(r, 64 == layout.size(array2));
+    REPORTER_ASSERT(r, 16 == layout.alignment(array2));
+    REPORTER_ASSERT(r, 16 == layout.stride(array2));
+}
+
+DEF_TEST(SkSLMemoryLayout430Test, r) {
+    SkSL::Context context;
+    SkSL::MemoryLayout layout(SkSL::MemoryLayout::k430_Standard);
+
+    // basic types
+    REPORTER_ASSERT(r,  4 == layout.size(*context.fFloat_Type));
+    REPORTER_ASSERT(r,  8 == layout.size(*context.fVec2_Type));
+    REPORTER_ASSERT(r, 12 == layout.size(*context.fVec3_Type));
+    REPORTER_ASSERT(r, 16 == layout.size(*context.fVec4_Type));
+    REPORTER_ASSERT(r,  4 == layout.size(*context.fInt_Type));
+    REPORTER_ASSERT(r,  8 == layout.size(*context.fIVec2_Type));
+    REPORTER_ASSERT(r, 12 == layout.size(*context.fIVec3_Type));
+    REPORTER_ASSERT(r, 16 == layout.size(*context.fIVec4_Type));
+    REPORTER_ASSERT(r,  1 == layout.size(*context.fBool_Type));
+    REPORTER_ASSERT(r,  2 == layout.size(*context.fBVec2_Type));
+    REPORTER_ASSERT(r,  3 == layout.size(*context.fBVec3_Type));
+    REPORTER_ASSERT(r,  4 == layout.size(*context.fBVec4_Type));
+    REPORTER_ASSERT(r, 16 == layout.size(*context.fMat2x2_Type));
+    REPORTER_ASSERT(r, 32 == layout.size(*context.fMat2x4_Type));
+    REPORTER_ASSERT(r, 48 == layout.size(*context.fMat3x3_Type));
+    REPORTER_ASSERT(r, 32 == layout.size(*context.fMat4x2_Type));
+    REPORTER_ASSERT(r, 64 == layout.size(*context.fMat4x4_Type));
+    REPORTER_ASSERT(r,  4 == layout.alignment(*context.fFloat_Type));
+    REPORTER_ASSERT(r,  8 == layout.alignment(*context.fVec2_Type));
+    REPORTER_ASSERT(r, 16 == layout.alignment(*context.fVec3_Type));
+    REPORTER_ASSERT(r, 16 == layout.alignment(*context.fVec4_Type));
+    REPORTER_ASSERT(r,  4 == layout.alignment(*context.fInt_Type));
+    REPORTER_ASSERT(r,  8 == layout.alignment(*context.fIVec2_Type));
+    REPORTER_ASSERT(r, 16 == layout.alignment(*context.fIVec3_Type));
+    REPORTER_ASSERT(r, 16 == layout.alignment(*context.fIVec4_Type));
+    REPORTER_ASSERT(r,  1 == layout.alignment(*context.fBool_Type));
+    REPORTER_ASSERT(r,  2 == layout.alignment(*context.fBVec2_Type));
+    REPORTER_ASSERT(r,  4 == layout.alignment(*context.fBVec3_Type));
+    REPORTER_ASSERT(r,  4 == layout.alignment(*context.fBVec4_Type));
+    REPORTER_ASSERT(r,  8 == layout.alignment(*context.fMat2x2_Type));
+    REPORTER_ASSERT(r, 16 == layout.alignment(*context.fMat2x4_Type));
+    REPORTER_ASSERT(r, 16 == layout.alignment(*context.fMat3x3_Type));
+    REPORTER_ASSERT(r,  8 == layout.alignment(*context.fMat4x2_Type));
+    REPORTER_ASSERT(r, 16 == layout.alignment(*context.fMat4x4_Type));
+
+    // struct 1
+    std::vector<SkSL::Type::Field> fields1;
+    fields1.emplace_back(SkSL::Modifiers(), SkString("a"), context.fVec3_Type.get());
+    SkSL::Type s1(SkString("s1"), fields1);
+    REPORTER_ASSERT(r, 16 == layout.size(s1));
+    REPORTER_ASSERT(r, 16 == layout.alignment(s1));
+
+    fields1.emplace_back(SkSL::Modifiers(), SkString("b"), context.fFloat_Type.get());
+    SkSL::Type s2(SkString("s2"), fields1);
+    REPORTER_ASSERT(r, 16 == layout.size(s2));
+    REPORTER_ASSERT(r, 16 == layout.alignment(s2));
+
+    fields1.emplace_back(SkSL::Modifiers(), SkString("c"), context.fBool_Type.get());
+    SkSL::Type s3(SkString("s3"), fields1);
+    REPORTER_ASSERT(r, 32 == layout.size(s3));
+    REPORTER_ASSERT(r, 16 == layout.alignment(s3));
+
+    // struct 2
+    std::vector<SkSL::Type::Field> fields2;
+    fields2.emplace_back(SkSL::Modifiers(), SkString("a"), context.fInt_Type.get());
+    SkSL::Type s4(SkString("s4"), fields2);
+    REPORTER_ASSERT(r, 4 == layout.size(s4));
+    REPORTER_ASSERT(r, 4 == layout.alignment(s4));
+
+    fields2.emplace_back(SkSL::Modifiers(), SkString("b"), context.fVec3_Type.get());
+    SkSL::Type s5(SkString("s5"), fields2);
+    REPORTER_ASSERT(r, 32 == layout.size(s5));
+    REPORTER_ASSERT(r, 16 == layout.alignment(s5));
+
+    // arrays
+    SkSL::Type array1(SkString("float[4]"), SkSL::Type::kArray_Kind, *context.fFloat_Type, 4);
+    REPORTER_ASSERT(r, 16 == layout.size(array1));
+    REPORTER_ASSERT(r, 4 == layout.alignment(array1));
+    REPORTER_ASSERT(r, 4 == layout.stride(array1));
+
+    SkSL::Type array2(SkString("vec4[4]"), SkSL::Type::kArray_Kind, *context.fVec4_Type, 4);
+    REPORTER_ASSERT(r, 64 == layout.size(array2));
+    REPORTER_ASSERT(r, 16 == layout.alignment(array2));
+    REPORTER_ASSERT(r, 16 == layout.stride(array2));
+}
+#endif