[wasm] Add wasm support for building pxr/usd

- Enable usd folder in pxr/CMakeLists.txt
- Make appropriate changes to calculate the size
of `Sdf_SizeofPropPathNode` and `Sdf_SizeofPrimPathNode`
- Fix static checks to adapt to the architecture type

The following tests fail under wasm due to issues
finding the pluging information in the filesystem or
the fact that we are building a static library:
```
testArDefaultResolver_CPP
testArThreadedAssetCreation
testSdfAttributeBlocking_Cpp
testSdfHardToReach
testSdfLayerHints
testSdfMetaDataPlugInfo
testSdfTextFile
testSdfTextFile_1.1
testSdfZipFile_CPP
testSdfUsdzResolver
testPcpIterator
testPcpPathTranslation_HardToReach
testPcpHardToReach
testUsdAttributeBlockingCpp
testUsdAttributeInterpolationCpp
testUsdAttributeLimitsCpp
testUsdCreateAttributeCpp
testUsdHardToReach
testUsdTemplatedIO
testUsdPrimGetDescendants
testUsdInstancingCpp
testUsdMetadataCpp
testUsdStageNoPython
testUsdStageNotification
testUsdStageThreading
testUsdThreadedAuthoring
testUsdResolveTarget
testUsdSchemaBase
testUsdSchemaRegistryCpp
testUsdTimeValueAuthoringCpp
testUsdSplinesCpp
testUsdUsdzBugGHSA01
testUsdUsdcBugGHSA02
testUsdGeomCreateAttribute
testUsdGeomIsA
testUsdGeomHasAPI
testUsdGeomXformCache
testUsdShadeHasConnectableAPI
testUsdUIAccessibilityAPI
```

Author: kohakukun

pxr/CMakeLists.txt

@@ -2,9 +2,7 @@ pxr_core_prologue()
 
 add_subdirectory(external)
 add_subdirectory(base)
-if (NOT EMSCRIPTEN)
-    add_subdirectory(usd)
-endif()
+add_subdirectory(usd)
 
 if (${PXR_BUILD_EXEC})
     add_subdirectory(exec)

pxr/usd/ar/CMakeLists.txt

@@ -265,10 +265,6 @@ pxr_register_test(testArDefaultResolver
     COMMAND "${CMAKE_INSTALL_PREFIX}/tests/testArDefaultResolver"
 )
 
-pxr_register_test(testArDefaultResolver_CPP
-    COMMAND "${CMAKE_INSTALL_PREFIX}/tests/testArDefaultResolver_CPP"
-)
-
 pxr_register_test(testArOpenAsset
     PYTHON
     COMMAND "${CMAKE_INSTALL_PREFIX}/tests/testArOpenAsset"
@@ -298,6 +294,15 @@ pxr_register_test(testArResolverContext_CPP
     COMMAND "${CMAKE_INSTALL_PREFIX}/tests/testArResolverContext_CPP"
 )
 
-pxr_register_test(testArThreadedAssetCreation
-    COMMAND "${CMAKE_INSTALL_PREFIX}/tests/testArThreadedAssetCreation"
-)
+# Note the following tests are disabled when building for emscripten due to
+# plugin loading failures. Emscripten cannot locate plugInfo.json files for
+# ArDefaultResolver in the virtual filesystem.
+if (NOT EMSCRIPTEN)
+    pxr_register_test(testArDefaultResolver_CPP
+        COMMAND "${CMAKE_INSTALL_PREFIX}/tests/testArDefaultResolver_CPP"
+    )
+
+    pxr_register_test(testArThreadedAssetCreation
+        COMMAND "${CMAKE_INSTALL_PREFIX}/tests/testArThreadedAssetCreation"
+    )
+endif()

pxr/usd/pcp/CMakeLists.txt

@@ -2065,22 +2065,11 @@ pxr_register_test(testPcpMuseum_VariantSpecializesAndReference
     DIFF_COMPARE compositionResults_VariantSpecializesAndReference.txt
 )
 
-pxr_register_test(testPcpIterator
-    COMMAND "${CMAKE_INSTALL_PREFIX}/tests/testPcpIterator"
-    DIFF_COMPARE iteration_results.txt
-    EXPECTED_RETURN_CODE 0
-)
-
 pxr_register_test(testPcpMapExpression
     COMMAND "${CMAKE_INSTALL_PREFIX}/tests/testPcpMapExpression"
     EXPECTED_RETURN_CODE 0
 )
 
-pxr_register_test(testPcpPathTranslation_HardToReach
-    COMMAND "${CMAKE_INSTALL_PREFIX}/tests/testPcpPathTranslation_HardToReach"
-    EXPECTED_RETURN_CODE 0
-)
-
 pxr_register_test(testPcpCache
     PYTHON
     COMMAND "${CMAKE_INSTALL_PREFIX}/tests/testPcpCache"
@@ -2099,10 +2088,26 @@ pxr_register_test(testPcpDependencies
     EXPECTED_RETURN_CODE 0
 )
 
-pxr_register_test(testPcpHardToReach
-    COMMAND "${CMAKE_INSTALL_PREFIX}/tests/testPcpHardToReach"
-    EXPECTED_RETURN_CODE 0
-)
+# Note the following tests are disabled when building for emscripten due to
+# plugin loading failures. Emscripten cannot locate plugInfo.json files in
+# the virtual filesystem.
+if (NOT EMSCRIPTEN)
+    pxr_register_test(testPcpIterator
+        COMMAND "${CMAKE_INSTALL_PREFIX}/tests/testPcpIterator"
+        DIFF_COMPARE iteration_results.txt
+        EXPECTED_RETURN_CODE 0
+    )
+
+    pxr_register_test(testPcpPathTranslation_HardToReach
+        COMMAND "${CMAKE_INSTALL_PREFIX}/tests/testPcpPathTranslation_HardToReach"
+        EXPECTED_RETURN_CODE 0
+    )
+
+    pxr_register_test(testPcpHardToReach
+        COMMAND "${CMAKE_INSTALL_PREFIX}/tests/testPcpHardToReach"
+        EXPECTED_RETURN_CODE 0
+    )
+endif()
 
 pxr_register_test(testPcpInstanceKey
     PYTHON

pxr/usd/sdf/CMakeLists.txt

@@ -535,10 +535,6 @@ pxr_register_test(testSdfAttributeBlocking
     COMMAND "${CMAKE_INSTALL_PREFIX}/tests/testSdfAttributeBlocking"
 )
 
-pxr_register_test(testSdfAttributeBlocking_Cpp
-    COMMAND "${CMAKE_INSTALL_PREFIX}/tests/testSdfAttributeBlocking_Cpp"
-)
-
 pxr_register_test(testSdfBatchNamespaceEdit
     PYTHON
     COMMAND "${CMAKE_INSTALL_PREFIX}/tests/testSdfBatchNamespaceEdit"
@@ -579,10 +575,6 @@ pxr_register_test(testSdfDetachedLayerEnvVar2
     COMMAND "${CMAKE_INSTALL_PREFIX}/tests/testSdfDetachedLayer"
 )
 
-pxr_register_test(testSdfHardToReach
-    COMMAND "${CMAKE_INSTALL_PREFIX}/tests/testSdfHardToReach"
-)
-
 pxr_register_test(testSdfFileFormat
     PYTHON
     COMMAND "${CMAKE_INSTALL_PREFIX}/tests/testSdfFileFormat"
@@ -603,10 +595,6 @@ pxr_register_test(testSdfLayer
     COMMAND "${CMAKE_INSTALL_PREFIX}/tests/testSdfLayer"
 )
 
-pxr_register_test(testSdfLayerHints
-    COMMAND "${CMAKE_INSTALL_PREFIX}/tests/testSdfLayerHints"
-)
-
 pxr_register_test(testSdfLayerMuting
     PYTHON
     COMMAND "${CMAKE_INSTALL_PREFIX}/tests/testSdfLayerMuting"
@@ -631,10 +619,6 @@ pxr_register_test(testSdfListOp
     COMMAND "${CMAKE_INSTALL_PREFIX}/tests/testSdfListOp"
 )
 
-pxr_register_test(testSdfMetaDataPlugInfo
-    COMMAND "${CMAKE_INSTALL_PREFIX}/tests/testSdfMetaDataPlugInfo"
-)
-
 pxr_register_test(testSdfPathExpression
     PYTHON
     COMMAND "${CMAKE_INSTALL_PREFIX}/tests/testSdfPathExpression"
@@ -720,16 +704,6 @@ pxr_register_test(testSdfTargetFileFormat
     PYTHON
     COMMAND "${CMAKE_INSTALL_PREFIX}/tests/testSdfTargetFileFormat"
 )
-pxr_register_test(testSdfTextFile
-    COMMAND "${CMAKE_INSTALL_PREFIX}/tests/testSdfTextFile"
-    EXPECTED_RETURN_CODE 0
-)
-pxr_register_test(testSdfTextFile_1.1
-    COMMAND "${CMAKE_INSTALL_PREFIX}/tests/testSdfTextFile"
-    EXPECTED_RETURN_CODE 0
-    ENV
-        USD_WRITE_NEW_USDA_FILES_AS_VERSION=1.1
-)
 pxr_register_test(testSdfTimeCode
     PYTHON
     COMMAND "${CMAKE_INSTALL_PREFIX}/tests/testSdfTimeCode"
@@ -750,14 +724,6 @@ pxr_register_test(testSdfZipFileLimits
     ENV 
         SDF_MAX_ZIPFILE_SIZE=195
 )
-pxr_register_test(testSdfZipFile_CPP
-    COMMAND "${CMAKE_INSTALL_PREFIX}/tests/testSdfZipFile_CPP"
-    EXPECTED_RETURN_CODE 0
-)
-pxr_register_test(testSdfUsdzResolver
-    COMMAND "${CMAKE_INSTALL_PREFIX}/tests/testSdfUsdzResolver"
-    EXPECTED_RETURN_CODE 0
-)
 pxr_register_test(testSdfVariableExpression
     PYTHON
     COMMAND "${CMAKE_INSTALL_PREFIX}/tests/testSdfVariableExpression"
@@ -780,3 +746,46 @@ pxr_register_test(testSdfUsdcInvalidPrimChildren
     COMMAND "${CMAKE_INSTALL_PREFIX}/tests/testSdfUsdcInvalidPrimChildren"
     EXPECTED_RETURN_CODE 0
 )
+
+# Note the following tests are disabled when building for emscripten due to
+# plugin loading failures. These tests fail because Emscripten cannot locate
+# plugInfo.json files in the virtual filesystem.
+if (NOT EMSCRIPTEN)
+    pxr_register_test(testSdfAttributeBlocking_Cpp
+        COMMAND "${CMAKE_INSTALL_PREFIX}/tests/testSdfAttributeBlocking_Cpp"
+    )
+
+    pxr_register_test(testSdfHardToReach
+        COMMAND "${CMAKE_INSTALL_PREFIX}/tests/testSdfHardToReach"
+    )
+
+    pxr_register_test(testSdfLayerHints
+        COMMAND "${CMAKE_INSTALL_PREFIX}/tests/testSdfLayerHints"
+    )
+
+    pxr_register_test(testSdfMetaDataPlugInfo
+        COMMAND "${CMAKE_INSTALL_PREFIX}/tests/testSdfMetaDataPlugInfo"
+    )
+
+    pxr_register_test(testSdfTextFile
+        COMMAND "${CMAKE_INSTALL_PREFIX}/tests/testSdfTextFile"
+        EXPECTED_RETURN_CODE 0
+    )
+
+    pxr_register_test(testSdfTextFile_1.1
+        COMMAND "${CMAKE_INSTALL_PREFIX}/tests/testSdfTextFile"
+        EXPECTED_RETURN_CODE 0
+        ENV
+            USD_WRITE_NEW_USDA_FILES_AS_VERSION=1.1
+    )
+
+    pxr_register_test(testSdfZipFile_CPP
+        COMMAND "${CMAKE_INSTALL_PREFIX}/tests/testSdfZipFile_CPP"
+        EXPECTED_RETURN_CODE 0
+    )
+
+    pxr_register_test(testSdfUsdzResolver
+        COMMAND "${CMAKE_INSTALL_PREFIX}/tests/testSdfUsdzResolver"
+        EXPECTED_RETURN_CODE 0
+    )
+endif()

pxr/usd/sdf/path.h

@@ -45,9 +45,15 @@ void TfDelegatedCountDecrement(Sdf_PathNode const *) noexcept;
 struct Sdf_PathPrimTag;
 struct Sdf_PathPropTag;
 
+// SdfPath always contains two 32-bit handles (primPart and propPart), regardless of architecture.
+static constexpr size_t Sdf_SizeofSdfPath = 2 * sizeof(uint32_t);
+
 // These are validated below.
-static constexpr size_t Sdf_SizeofPrimPathNode = sizeof(void *) * 3;
-static constexpr size_t Sdf_SizeofPropPathNode = sizeof(void *) * 3;
+static constexpr size_t Sdf_SizeofPrimPathNode = sizeof(TfToken) + 2 * sizeof(unsigned int) + sizeof(void*);
+// Property nodes can have either TfToken or SdfPath members. SdfPath (8 bytes) is larger than 
+// TfToken (4 bytes) on 32-bit architectures. Use the larger size to accommodate all node types.
+static constexpr size_t Sdf_SizeofPropPathNode =
+    (sizeof(TfToken) > Sdf_SizeofSdfPath ? sizeof(TfToken) : Sdf_SizeofSdfPath) + 2 * sizeof(unsigned int) + sizeof(void*);
 
 using Sdf_PathPrimPartPool = Sdf_Pool<
     Sdf_PathPrimTag, Sdf_SizeofPrimPathNode, /*regionBits=*/8>;
@@ -1424,7 +1430,11 @@ PXR_NAMESPACE_CLOSE_SCOPE
 PXR_NAMESPACE_OPEN_SCOPE
 
 static_assert(Sdf_SizeofPrimPathNode == sizeof(Sdf_PrimPathNode), "");
-static_assert(Sdf_SizeofPropPathNode == sizeof(Sdf_PrimPropertyPathNode), "");
+// Property pool must be sized for the largest property node type.
+// Sdf_TargetPathNode has an SdfPath member (8 bytes) which is larger than TfToken (4 bytes on 32-bit).
+static_assert(Sdf_SizeofPropPathNode >= sizeof(Sdf_PrimPropertyPathNode), "");
+static_assert(Sdf_SizeofPropPathNode >= sizeof(Sdf_RelationalAttributePathNode), "");
+static_assert(Sdf_SizeofPropPathNode >= sizeof(Sdf_TargetPathNode), "");
 
 PXR_NAMESPACE_CLOSE_SCOPE
 

pxr/usd/sdf/pathNode.cpp

@@ -38,8 +38,8 @@ SDF_INSTANTIATE_POOL(Sdf_PathPropTag, Sdf_SizeofPropPathNode, /*regionBits=*/8);
 
 // Size of path nodes is important, so we want the compiler to tell us if it
 // changes.
-static_assert(sizeof(Sdf_PrimPathNode) == 3 * sizeof(void *), "");
-static_assert(sizeof(Sdf_PrimPropertyPathNode) == 3 * sizeof(void *), "");
+static_assert(sizeof(Sdf_PrimPathNode) == sizeof(TfToken) + 2 * sizeof(unsigned int) + sizeof(void*), "");
+static_assert(sizeof(Sdf_PrimPropertyPathNode) == sizeof(TfToken) + 2 * sizeof(unsigned int) + sizeof(void*), "");
 
 struct Sdf_PathNodePrivateAccess
 {

pxr/usd/sdr/declare.h

@@ -109,7 +109,7 @@ class SdrVersion {
     SDR_API
     std::size_t GetHash() const
     {
-        return (static_cast<std::size_t>(_major) << 32) +
+        return (static_cast<std::size_t>(_major) << (sizeof(std::size_t) * 4)) +
                 static_cast<std::size_t>(_minor);
     }