Expose the cDAC data contract for consumption on WASM.

src/coreclr/clrdatadescriptors.cmake

@@ -11,6 +11,7 @@ function(generate_data_descriptors)
   set(LIBRARY ${DATA_DESCRIPTORS_LIBRARY_NAME})
 
   set(DATA_DESCRIPTOR_SHARED_SOURCE_DIR "${CMAKE_CURRENT_FUNCTION_LIST_DIR}/debug/datadescriptor-shared")
+  set(DATA_DESCRIPTOR_SHARED_INCLUDE_DIR "${CMAKE_CURRENT_FUNCTION_LIST_DIR}/debug/datadescriptor-shared/inc")
   set(GENERATED_CDAC_DESCRIPTOR_DIR "${CMAKE_CURRENT_BINARY_DIR}/cdac-${LIBRARY}")
 
   # configure contract export name
@@ -73,6 +74,7 @@ function(generate_data_descriptors)
     )
     add_dependencies(${LIBRARY} ${INTERMEDIARY_LIBRARY})
 
+    target_include_directories(${LIBRARY} PUBLIC ${DATA_DESCRIPTOR_SHARED_INCLUDE_DIR})
     target_include_directories(${LIBRARY} PRIVATE ${GENERATED_CDAC_DESCRIPTOR_DIR})
 
     # inherit definitions, include directories, and dependencies from the INTERFACE target

src/coreclr/debug/datadescriptor-shared/contract-descriptor.c.in

@@ -1,7 +1,6 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
-#include <stdint.h>
 #include "contractconfiguration.h"
 
 #ifdef _MSC_VER
@@ -10,22 +9,11 @@
 #define DLLEXPORT __attribute__((visibility("default")))
 #endif
 
-struct ContractDescriptor
-{
-    uint64_t magic;
-    uint32_t flags;
-    const uint32_t descriptor_size;
-    const char *descriptor;
-    const uint32_t pointer_data_count;
-    uint32_t pad0;
-    const void** pointer_data;
-};
-
 // POINTER_DATA_NAME and CONTRACT_NAME are macros provided by
 // contractconfiguration.h which is configured by CMake
 extern const void* POINTER_DATA_NAME[];
 
-#if EXPORT_CONTRACT
+#ifdef EXPORT_CONTRACT
 DLLEXPORT
 #endif // EXPORT_CONTRACT
 struct ContractDescriptor CONTRACT_NAME = {
@@ -36,3 +24,19 @@ struct ContractDescriptor CONTRACT_NAME = {
     .pointer_data_count = %%pointerDataCount%%,
     .pointer_data = &POINTER_DATA_NAME[0],
 };
+
+// When using emscripten, we need to export the contract descriptor
+// symbol through a function export to ensure it is not removed by the linker.
+// Due to linking order, the export may also need to be added to
+// the EXPORTED_FUNCTIONS setting for emcc.
+// See https://emscripten.org/docs/getting_started/FAQ.html#why-do-functions-in-my-c-c-source-code-vanish-when-i-compile-to-webassembly
+#if defined(EXPORT_CONTRACT) && defined(__EMSCRIPTEN__)
+#include <emscripten.h>
+
+#define _GETTER_NAME(exportname) Get ## exportname
+#define GETTER_NAME(exportname) _GETTER_NAME(exportname)
+extern void* EMSCRIPTEN_KEEPALIVE GETTER_NAME(CONTRACT_NAME)()
+{
+    return (void*)&CONTRACT_NAME;
+}
+#endif // EXPORT_CONTRACT && __EMSCRIPTEN__

src/coreclr/debug/datadescriptor-shared/contractconfiguration.h.in

@@ -1,6 +1,8 @@
 #pragma once
 
-#define POINTER_DATA_NAME @POINTER_DATA_NAME@
-#define CONTRACT_NAME @CONTRACT_NAME@
+#include <contract-descriptor.h>
 
-#define EXPORT_CONTRACT @EXPORT_CONTRACT@
+#cmakedefine POINTER_DATA_NAME @POINTER_DATA_NAME@
+#cmakedefine CONTRACT_NAME @CONTRACT_NAME@
+
+#cmakedefine EXPORT_CONTRACT @EXPORT_CONTRACT@

src/coreclr/debug/datadescriptor-shared/contractdescriptorstub.c

@@ -1,7 +1,6 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
-#include <stdint.h>
 #include "contractconfiguration.h"
 
 #ifdef _MSC_VER
@@ -10,17 +9,6 @@
 #define DLLEXPORT __attribute__((visibility("default")))
 #endif
 
-struct ContractDescriptor
-{
-    uint64_t magic;
-    uint32_t flags;
-    const uint32_t descriptor_size;
-    const char *descriptor;
-    const uint32_t pointer_data_count;
-    uint32_t pad0;
-    const void** pointer_data;
-};
-
 // POINTER_DATA_NAME and CONTRACT_NAME are macros provided by
 // contractconfiguration.h which is configured by CMake
 extern const void* POINTER_DATA_NAME[];

src/coreclr/debug/datadescriptor-shared/inc/contract-descriptor.h

@@ -0,0 +1,20 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+#ifndef CONTRACT_DESCRIPTOR_H
+#define CONTRACT_DESCRIPTOR_H
+
+#include <stdint.h>
+
+struct ContractDescriptor
+{
+    uint64_t magic;
+    uint32_t flags;
+    const uint32_t descriptor_size;
+    const char* descriptor;
+    const uint32_t pointer_data_count;
+    uint32_t pad0;
+    const void** pointer_data;
+};
+
+#endif // CONTRACT_DESCRIPTOR_H

src/coreclr/dlls/mscoree/coreclr/CMakeLists.txt

@@ -74,10 +74,6 @@ if (NOT CLR_CMAKE_HOST_ARCH_WASM)
     set(LIB_INTEROP interop)
 endif(NOT CLR_CMAKE_HOST_ARCH_WASM)
 
-set(LIB_CDAC_CONTRACT_DESCRIPTOR cdac_contract_descriptor)
-set(LIB_CDAC_GC_WKS_DESCRIPTOR gc_wks_descriptor)
-set(LIB_CDAC_GC_SVR_DESCRIPTOR gc_svr_descriptor)
-
 if (CLR_CMAKE_HOST_UNIX AND NOT CLR_CMAKE_TARGET_ARCH_WASM)
     set(LIB_UNWINDER unwinder_wks)
 endif (CLR_CMAKE_HOST_UNIX AND NOT CLR_CMAKE_TARGET_ARCH_WASM)
@@ -106,13 +102,13 @@ set(CORECLR_LIBRARIES
     ${LIB_INTEROP}
     coreclrminipal
     gc_pal
-    ${LIB_CDAC_CONTRACT_DESCRIPTOR}
-    ${LIB_CDAC_GC_WKS_DESCRIPTOR}
+    cdac_contract_descriptor
+    gc_wks_descriptor
 )
 
 if (FEATURE_SVR_GC)
     list(APPEND CORECLR_LIBRARIES
-        ${LIB_CDAC_GC_SVR_DESCRIPTOR}
+        gc_svr_descriptor
     )
 endif(FEATURE_SVR_GC)
 
@@ -188,11 +184,11 @@ if(FEATURE_JIT)
     set(CORECLR_STATIC_CLRJIT_STATIC clrjit_static)
 endif(FEATURE_JIT)
 
-if(NOT CLR_CMAKE_HOST_ARCH_WASM)
-    set(CEE_WKS_STATIC cee_wks_mergeable)
-else()
+if(CLR_CMAKE_HOST_ARCH_WASM)
     set(CEE_WKS_STATIC cee_wks)
-endif(NOT CLR_CMAKE_HOST_ARCH_WASM)
+else()
+    set(CEE_WKS_STATIC cee_wks_mergeable)
+endif()
 
 if (CLR_CMAKE_TARGET_OSX)
     find_library(FOUNDATION Foundation REQUIRED)
@@ -202,7 +198,7 @@ if(NOT CLR_CMAKE_HOST_ARCH_WASM)
     target_link_libraries(coreclr PUBLIC ${CORECLR_LIBRARIES} ${CLRJIT_STATIC} ${CLRINTERPRETER_STATIC} cee_wks_core cee_wks ${FOUNDATION})
 endif(NOT CLR_CMAKE_HOST_ARCH_WASM)
 
-target_link_libraries(coreclr_static PUBLIC ${CORECLR_LIBRARIES} cee_wks_core ${CORECLR_STATIC_CLRJIT_STATIC} ${CLRINTERPRETER_STATIC} ${CEE_WKS_STATIC} ${FOUNDATION})
+target_link_libraries(coreclr_static PUBLIC ${CORECLR_LIBRARIES} ${CORECLR_STATIC_CLRJIT_STATIC} ${CLRINTERPRETER_STATIC} cee_wks_core ${CEE_WKS_STATIC} ${FOUNDATION})
 target_compile_definitions(coreclr_static PUBLIC CORECLR_EMBEDDED)
 
 if (CLR_CMAKE_HOST_ANDROID)

src/coreclr/hosts/corerun/CMakeLists.txt

@@ -77,6 +77,7 @@ else()
                 -sEXIT_RUNTIME=1
                 -sINITIAL_MEMORY=134217728
                 -sSTACK_SIZE=5MB
+                -sEXPORTED_FUNCTIONS=_main,_GetDotNetRuntimeContractDescriptor
                 -sENVIRONMENT=node,shell,web
                 -Wl,-error-limit=0)
 

src/coreclr/interpreter/CMakeLists.txt

@@ -16,11 +16,11 @@ set(INTERPRETER_LINK_LIBRARIES
 )
 
 if(CLR_CMAKE_HOST_WIN32)
-    list(APPEND INTERPRETER_LINK_LIBRARIES
-        ${STATIC_MT_CRT_LIB}
-        ${STATIC_MT_VCRT_LIB}
-    )
-endif(CLR_CMAKE_HOST_WIN32)
+  list(APPEND INTERPRETER_LINK_LIBRARIES
+    ${STATIC_MT_CRT_LIB}
+    ${STATIC_MT_VCRT_LIB}
+  )
+endif()
 
 if(CLR_CMAKE_HOST_WIN32)
     set(CLRINTERPRETER_EXPORTS ${CMAKE_CURRENT_LIST_DIR}/clrinterpreter.exports)

src/coreclr/vm/wks/CMakeLists.txt

@@ -52,9 +52,7 @@ add_dependencies(cee_wks_mergeable precompiled_asm)
 target_compile_definitions(cee_wks_mergeable PUBLIC FEATURE_STATICALLY_LINKED)
 target_compile_definitions(cee_wks_mergeable PUBLIC CORECLR_EMBEDDED)
 
-if (NOT CLR_CMAKE_HOST_ARCH_WASM)
-  target_compile_definitions(cee_wks_core PRIVATE -DGC_DESCRIPTOR)
-endif (NOT CLR_CMAKE_HOST_ARCH_WASM)
+target_compile_definitions(cee_wks_core PRIVATE GC_DESCRIPTOR)
 
 if (CLR_CMAKE_HOST_WIN32)
     link_natvis_sources_for_target(cee_wks INTERFACE ../vm.natvis)