Initial changes for explicit symbol visibility for shared library builds

Added conditional export macros in llvm/Support/Compiler.h
Update cmake code to allow building llvm-shlib on windows appending /WHOLEARCHIVE:lib to the linker options.
Remove the hardcoded CMake error from using LLVM_BUILD_LLVM_DYLIB on windows.
Updated CMake to define macros to enable export macros.
Use /Zc:dllexportInlines- when compiling with clang-cl on windows with a
opt out CMake option to disable using it.
Replace LLVM_EXTERNAL_VISIBILITY with new export macros.

Author: fsfod

llvm/CMakeLists.txt

@@ -839,22 +839,36 @@ endif()
 
 if(MSVC)
   option(LLVM_BUILD_LLVM_C_DYLIB "Build LLVM-C.dll (Windows only)" ON)
-  # Set this variable to OFF here so it can't be set with a command-line
-  # argument.
-  set (LLVM_LINK_LLVM_DYLIB OFF)
+  if(NOT LLVM_BUILD_LLVM_DYLIB_VIS)
+    # Set this variable to OFF here so it can't be set with a command-line
+    # argument.
+    set (LLVM_LINK_LLVM_DYLIB OFF)
+  endif()
   if (BUILD_SHARED_LIBS)
     message(FATAL_ERROR "BUILD_SHARED_LIBS options is not supported on Windows.")
   endif()
-else()
-  option(LLVM_LINK_LLVM_DYLIB "Link tools against the libllvm dynamic library" OFF)
+ else()
   option(LLVM_BUILD_LLVM_C_DYLIB "Build libllvm-c re-export library (Darwin only)" OFF)
+endif()
+
+if(NOT MSVC OR LLVM_BUILD_LLVM_DYLIB_VIS)
+  option(LLVM_LINK_LLVM_DYLIB "Link tools against the libllvm dynamic library" OFF)
   set(LLVM_BUILD_LLVM_DYLIB_default OFF)
   if(LLVM_LINK_LLVM_DYLIB OR LLVM_BUILD_LLVM_C_DYLIB)
     set(LLVM_BUILD_LLVM_DYLIB_default ON)
   endif()
   option(LLVM_BUILD_LLVM_DYLIB "Build libllvm dynamic library" ${LLVM_BUILD_LLVM_DYLIB_default})
 endif()
 
+# Build llvm dynamic library with explicit symbol visibility on windows and default hidden symbol visibility on Linux
+if(LLVM_BUILD_LLVM_DYLIB_VIS)
+  set(LLVM_BUILD_LLVM_DYLIB ON)
+  if(MSVC)
+    option(LLVM_DYLIB_EXPORT_INLINES "Force inline members of class to be dll exported when
+           building with clang-cl so the libllvm dll is compatible with MSVC" OFF)
+  endif()
+endif()
+
 if (LLVM_LINK_LLVM_DYLIB AND BUILD_SHARED_LIBS)
   message(FATAL_ERROR "Cannot enable BUILD_SHARED_LIBS with LLVM_LINK_LLVM_DYLIB.  We recommend disabling BUILD_SHARED_LIBS.")
 endif()

llvm/cmake/modules/AddLLVM.cmake

@@ -606,6 +606,10 @@ function(llvm_add_library name)
         endif()
       endforeach()
     endif()
+
+    if(ARG_DISABLE_LLVM_LINK_LLVM_DYLIB)
+      target_compile_definitions(${obj_name} PRIVATE LLVM_BUILD_STATIC)
+    endif()
   endif()
 
   if(ARG_SHARED AND ARG_STATIC)
@@ -641,8 +645,36 @@ function(llvm_add_library name)
   endif()
   set_target_properties(${name} PROPERTIES FOLDER "${subproject_title}/Libraries")
 
+  ## If were compiling with clang-cl use /Zc:dllexportInlines- to exclude inline 
+  ## class members from being dllexport'ed to reduce compile time.
+  ## This will also keep us below the 64k exported symbol limit
+  ## https://blog.llvm.org/2018/11/30-faster-windows-builds-with-clang-cl_14.html
+  if(LLVM_BUILD_LLVM_DYLIB AND NOT LLVM_DYLIB_EXPORT_INLINES AND 
+     MSVC AND CMAKE_CXX_COMPILER_ID MATCHES Clang)
+    target_compile_options(${name} PUBLIC /Zc:dllexportInlines-)
+    if(TARGET ${obj_name})
+      target_compile_options(${obj_name} PUBLIC /Zc:dllexportInlines-)
+    endif()
+  endif()
+
   if(ARG_COMPONENT_LIB)
     set_target_properties(${name} PROPERTIES LLVM_COMPONENT TRUE)
+    if(LLVM_BUILD_LLVM_DYLIB OR BUILD_SHARED_LIBS)
+      target_compile_definitions(${name} PRIVATE LLVM_EXPORTS)
+    endif()
+
+    # When building shared objects for each target there are some internal APIs
+    # that are used across shared objects which we can't hide.
+    if (LLVM_BUILD_LLVM_DYLIB_VIS AND NOT BUILD_SHARED_LIBS AND NOT APPLE AND
+        (NOT (WIN32 OR CYGWIN) OR (MINGW AND CMAKE_CXX_COMPILER_ID MATCHES "Clang")) AND
+        NOT (${CMAKE_SYSTEM_NAME} MATCHES "AIX") AND
+        NOT DEFINED CMAKE_CXX_VISIBILITY_PRESET)
+
+      set_target_properties(${name} PROPERTIES
+                            C_VISIBILITY_PRESET hidden
+                            CXX_VISIBILITY_PRESET hidden
+                            VISIBILITY_INLINES_HIDDEN YES)
+    endif()
     set_property(GLOBAL APPEND PROPERTY LLVM_COMPONENT_LIBS ${name})
   endif()
 
@@ -741,6 +773,9 @@ function(llvm_add_library name)
     if (LLVM_LINK_LLVM_DYLIB AND NOT ARG_DISABLE_LLVM_LINK_LLVM_DYLIB)
       set(llvm_libs LLVM)
     else()
+      if(ARG_DISABLE_LLVM_LINK_LLVM_DYLIB)
+        target_compile_definitions(${name} PRIVATE LLVM_BUILD_STATIC)
+      endif()
       llvm_map_components_to_libnames(llvm_libs
        ${ARG_LINK_COMPONENTS}
        ${LLVM_LINK_COMPONENTS}
@@ -1116,6 +1151,16 @@ macro(add_llvm_executable name)
   if (ARG_EXPORT_SYMBOLS)
     export_executable_symbols(${name})
   endif()
+
+  if(ARG_DISABLE_LLVM_LINK_LLVM_DYLIB OR NOT LLVM_LINK_LLVM_DYLIB)
+    target_compile_definitions(${name} PRIVATE LLVM_BUILD_STATIC)
+  endif()
+
+  if(LLVM_BUILD_LLVM_DYLIB_VIS AND NOT LLVM_DYLIB_EXPORT_INLINES AND
+     MSVC AND CMAKE_CXX_COMPILER_ID MATCHES Clang)
+    # This has to match how the libraries the executable is linked to are built or there be linker errors.
+    target_compile_options(${name} PRIVATE /Zc:dllexportInlines-)
+  endif()
 endmacro(add_llvm_executable name)
 
 # add_llvm_pass_plugin(name [NO_MODULE] ...)

llvm/cmake/modules/HandleLLVMOptions.cmake

@@ -754,6 +754,12 @@ if (MSVC)
       # any code that uses the LLVM_ALIGNAS macro), so this is must be disabled to
       # avoid unwanted alignment warnings.
       -wd4324 # Suppress 'structure was padded due to __declspec(align())'
+      # This is triggered for every variable that is a template type of a class even 
+      # if there private when the class is dllexport'ed
+      -wd4251 # Suppress 'needs to have dll-interface to be used by clients'
+      # We only putting dll export on classes with out of line members so this 
+      # warning gets triggered a lot for bases we haven't exported'
+      -wd4275 # non dll-interface class used as base for dll-interface class
 
       # Promoted warnings.
       -w14062 # Promote 'enumerator in switch of enum is not handled' to level 1 warning.

llvm/include/llvm/ADT/Any.h

@@ -25,7 +25,7 @@
 
 namespace llvm {
 
-class LLVM_EXTERNAL_VISIBILITY Any {
+class LLVM_ABI Any {
 
   // The `Typeid<T>::Id` static data member below is a globally unique
   // identifier for the type `T`. It is explicitly marked with default

llvm/include/llvm/Analysis/LazyCallGraph.h

@@ -416,7 +416,7 @@ class LazyCallGraph {
   /// outer structure. SCCs do not support mutation of the call graph, that
   /// must be done through the containing \c RefSCC in order to fully reason
   /// about the ordering and connections of the graph.
-  class LLVM_EXTERNAL_VISIBILITY SCC {
+  class LLVM_ABI SCC {
     friend class LazyCallGraph;
     friend class LazyCallGraph::Node;
 

llvm/include/llvm/Analysis/LoopInfo.h

@@ -41,7 +41,7 @@ extern template class LoopBase<BasicBlock, Loop>;
 
 /// Represents a single loop in the control flow graph.  Note that not all SCCs
 /// in the CFG are necessarily loops.
-class LLVM_EXTERNAL_VISIBILITY Loop : public LoopBase<BasicBlock, Loop> {
+class LLVM_ABI Loop : public LoopBase<BasicBlock, Loop> {
 public:
   /// A range representing the start and end location of a loop.
   class LocRange {

llvm/include/llvm/Analysis/LoopNestAnalysis.h

@@ -25,7 +25,7 @@ using LoopVectorTy = SmallVector<Loop *, 8>;
 class LPMUpdater;
 
 /// This class represents a loop nest and can be used to query its properties.
-class LLVM_EXTERNAL_VISIBILITY LoopNest {
+class LLVM_ABI LoopNest {
 public:
   using InstrVectorTy = SmallVector<const Instruction *>;
 

llvm/include/llvm/CodeGen/MachineFunction.h

@@ -254,7 +254,7 @@ struct LandingPadInfo {
       : LandingPadBlock(MBB) {}
 };
 
-class LLVM_EXTERNAL_VISIBILITY MachineFunction {
+class LLVM_ABI MachineFunction {
   Function &F;
   const LLVMTargetMachine &Target;
   const TargetSubtargetInfo *STI;

llvm/include/llvm/IR/Function.h

@@ -60,8 +60,7 @@ class User;
 class BranchProbabilityInfo;
 class BlockFrequencyInfo;
 
-class LLVM_EXTERNAL_VISIBILITY Function : public GlobalObject,
-                                          public ilist_node<Function> {
+class LLVM_ABI Function : public GlobalObject, public ilist_node<Function> {
 public:
   using BasicBlockListType = SymbolTableList<BasicBlock>;
 

llvm/include/llvm/IR/Module.h

@@ -62,7 +62,7 @@ class VersionTuple;
 /// constant references to global variables in the module.  When a global
 /// variable is destroyed, it should have no entries in the GlobalList.
 /// The main container class for the LLVM Intermediate Representation.
-class LLVM_EXTERNAL_VISIBILITY Module {
+class LLVM_ABI Module {
   /// @name Types And Enumerations
   /// @{
 public:

llvm/include/llvm/Support/Compiler.h

@@ -114,7 +114,8 @@
 /// this attribute will be made public and visible outside of any shared library
 /// they are linked in to.
 
-#if LLVM_HAS_CPP_ATTRIBUTE(gnu::visibility)
+#if LLVM_HAS_CPP_ATTRIBUTE(gnu::visibility) && defined(__GNUC__) &&            \
+    !defined(__clang__)
 #define LLVM_ATTRIBUTE_VISIBILITY_HIDDEN [[gnu::visibility("hidden")]]
 #define LLVM_ATTRIBUTE_VISIBILITY_DEFAULT [[gnu::visibility("default")]]
 #elif __has_attribute(visibility)
@@ -125,18 +126,79 @@
 #define LLVM_ATTRIBUTE_VISIBILITY_DEFAULT
 #endif
 
-
-#if (!(defined(_WIN32) || defined(__CYGWIN__)) ||                              \
-     (defined(__MINGW32__) && defined(__clang__)))
-#define LLVM_LIBRARY_VISIBILITY LLVM_ATTRIBUTE_VISIBILITY_HIDDEN
 #if defined(LLVM_BUILD_LLVM_DYLIB) || defined(LLVM_BUILD_SHARED_LIBS)
 #define LLVM_EXTERNAL_VISIBILITY LLVM_ATTRIBUTE_VISIBILITY_DEFAULT
 #else
 #define LLVM_EXTERNAL_VISIBILITY
 #endif
+
+#if (!(defined(_WIN32) || defined(__CYGWIN__)) ||                              \
+     (defined(__MINGW32__) && defined(__clang__)))
+#define LLVM_LIBRARY_VISIBILITY LLVM_ATTRIBUTE_VISIBILITY_HIDDEN
+#define LLVM_ALWAYS_EXPORT LLVM_ATTRIBUTE_VISIBILITY_DEFAULT
+#elif defined(_WIN32)
+#define LLVM_ALWAYS_EXPORT __declspec(dllexport)
+#define LLVM_LIBRARY_VISIBILITY
 #else
 #define LLVM_LIBRARY_VISIBILITY
-#define LLVM_EXTERNAL_VISIBILITY
+#define LLVM_ALWAYS_EXPORT
+#endif
+
+/// LLVM_ABI is the main export/visibility macro to mark something as explicitly
+/// exported when llvm is built as a shared library with everything else that is
+/// unannotated will have internal visibility.
+///
+/// LLVM_EXPORT_TEMPLATE is used on explicit template instantiations in source
+/// files that were declared extern in a header. This macro is only set as a
+/// compiler export attribute on windows, on other platforms it does nothing.
+///
+/// LLVM_TEMPLATE_ABI is for annotating extern template declarations in headers
+/// for both functions and classes. On windows its turned in to dllimport for
+/// library consumers, for other platforms its a default visibility attribute.
+///
+/// LLVM_C_ABI is used to annotated functions and data that need to be exported
+/// for the libllvm-c API. This used both for the llvm-c headers and for the
+/// functions declared in the different Target's c++ source files that don't
+/// include the header forward declaring them.
+#ifndef LLVM_ABI_GENERATING_ANNOTATIONS
+// Marker to add to classes or functions in public headers that should not have
+// export macros added to them by the clang tool
+#define LLVM_ABI_NOT_EXPORTED
+#if defined(LLVM_BUILD_LLVM_DYLIB) || defined(LLVM_BUILD_SHARED_LIBS) ||       \
+    defined(LLVM_ENABLE_PLUGINS)
+// Some libraries like those for tablegen are linked in to tools that used
+// in the build so can't depend on the llvm shared library. If export macros
+// were left enabled when building these we would get duplicate or
+// missing symbol linker errors on windows.
+#if defined(LLVM_BUILD_STATIC)
+#define LLVM_ABI
+#define LLVM_TEMPLATE_ABI
+#define LLVM_EXPORT_TEMPLATE
+#elif defined(_WIN32)
+#if defined(LLVM_EXPORTS)
+#define LLVM_ABI __declspec(dllexport)
+#define LLVM_TEMPLATE_ABI
+#define LLVM_EXPORT_TEMPLATE __declspec(dllexport)
+#else
+#define LLVM_ABI __declspec(dllimport)
+#define LLVM_TEMPLATE_ABI __declspec(dllimport)
+#define LLVM_EXPORT_TEMPLATE
+#endif
+#elif defined(__ELF__)
+#define LLVM_ABI LLVM_ATTRIBUTE_VISIBILITY_DEFAULT
+#define LLVM_TEMPLATE_ABI LLVM_ATTRIBUTE_VISIBILITY_DEFAULT
+#define LLVM_EXPORT_TEMPLATE
+#elif defined(__MACH__) || defined(__WASM__)
+#define LLVM_ABI LLVM_ATTRIBUTE_VISIBILITY_DEFAULT
+#define LLVM_TEMPLATE_ABI
+#define LLVM_EXPORT_TEMPLATE
+#endif
+#else
+#define LLVM_ABI
+#define LLVM_TEMPLATE_ABI
+#define LLVM_EXPORT_TEMPLATE
+#endif
+#define LLVM_C_ABI LLVM_ABI
 #endif
 
 #if defined(__GNUC__)

llvm/tools/llvm-shlib/CMakeLists.txt

@@ -11,7 +11,7 @@ if(LLVM_LINK_LLVM_DYLIB AND LLVM_DYLIB_EXPORTED_SYMBOL_FILE)
 endif()
 
 if(LLVM_BUILD_LLVM_DYLIB)
-  if(MSVC)
+  if(MSVC AND NOT LLVM_BUILD_LLVM_DYLIB_VIS)
     message(FATAL_ERROR "Generating libLLVM is not supported on MSVC")
   endif()
   if(ZOS)
@@ -49,18 +49,27 @@ if(LLVM_BUILD_LLVM_DYLIB)
     ${CMAKE_CURRENT_SOURCE_DIR}/simple_version_script.map.in
     ${LLVM_LIBRARY_DIR}/tools/llvm-shlib/simple_version_script.map)
 
-    # GNU ld doesn't resolve symbols in the version script.
-    set(LIB_NAMES -Wl,--whole-archive ${LIB_NAMES} -Wl,--no-whole-archive)
-    if (NOT LLVM_LINKER_IS_SOLARISLD AND NOT MINGW)
-      # Solaris ld does not accept global: *; so there is no way to version *all* global symbols
-      set(LIB_NAMES -Wl,--version-script,${LLVM_LIBRARY_DIR}/tools/llvm-shlib/simple_version_script.map ${LIB_NAMES})
-    endif()
-    if (NOT MINGW AND NOT LLVM_LINKER_IS_SOLARISLD_ILLUMOS)
-      # Optimize function calls for default visibility definitions to avoid PLT and
-      # reduce dynamic relocations.
-      # Note: for -fno-pic default, the address of a function may be different from
-      # inside and outside libLLVM.so.
-      target_link_options(LLVM PRIVATE LINKER:-Bsymbolic-functions)
+    if(MSVC)
+      target_link_directories(LLVM PRIVATE ${LLVM_LIBRARY_DIR})
+      foreach(library ${LIB_NAMES})
+        # FIXME figure out how to use LINK_LIBRARY:WHOLE_ARCHIVE without cmake errors
+        # target_link_libraries(LLVM PRIVATE  "$<LINK_LIBRARY:WHOLE_ARCHIVE,${library}>" )
+        target_link_options(LLVM PRIVATE /WHOLEARCHIVE:${library}.lib)
+      endforeach()
+    else()
+      # GNU ld doesn't resolve symbols in the version script.
+      set(LIB_NAMES -Wl,--whole-archive ${LIB_NAMES} -Wl,--no-whole-archive)
+      if (NOT LLVM_LINKER_IS_SOLARISLD AND NOT MINGW)
+        # Solaris ld does not accept global: *; so there is no way to version *all* global symbols
+        set(LIB_NAMES -Wl,--version-script,${LLVM_LIBRARY_DIR}/tools/llvm-shlib/simple_version_script.map ${LIB_NAMES})
+      endif()
+      if (NOT MINGW AND NOT LLVM_LINKER_IS_SOLARISLD_ILLUMOS)
+        # Optimize function calls for default visibility definitions to avoid PLT and
+        # reduce dynamic relocations.
+        # Note: for -fno-pic default, the address of a function may be different from
+        # inside and outside libLLVM.so.
+        target_link_options(LLVM PRIVATE LINKER:-Bsymbolic-functions)
+      endif()
     endif()
   endif()
 

llvm/utils/TableGen/Basic/CMakeLists.txt

@@ -8,7 +8,7 @@ set(LLVM_LINK_COMPONENTS
   TableGen
   )
 
-add_llvm_library(LLVMTableGenBasic OBJECT EXCLUDE_FROM_ALL
+add_llvm_library(LLVMTableGenBasic OBJECT EXCLUDE_FROM_ALL DISABLE_LLVM_LINK_LLVM_DYLIB
   CodeGenIntrinsics.cpp
   SDNodeProperties.cpp
 )

llvm/utils/TableGen/Common/CMakeLists.txt

@@ -10,7 +10,7 @@ set(LLVM_LINK_COMPONENTS
   TableGen
   )
 
-add_llvm_library(LLVMTableGenCommon STATIC OBJECT EXCLUDE_FROM_ALL
+add_llvm_library(LLVMTableGenCommon STATIC OBJECT EXCLUDE_FROM_ALL DISABLE_LLVM_LINK_LLVM_DYLIB
   GlobalISel/CodeExpander.cpp
   GlobalISel/CombinerUtils.cpp
   GlobalISel/CXXPredicates.cpp