[mlir] Add MLIR-C dylib.

Per discussion on discord and various feature requests across bindings (Haskell and Rust bindings authors have asked me directly), we should be building a link-ready MLIR-C dylib which exports the C API and can be used without linking to anything else.

This patch:

* Adds a new MLIR-C aggregate shared library (libMLIR-C.so), which is similar in name and function to libLLVM-C.so.
* It is guarded by the new CMake option MLIR_BUILD_MLIR_C_DYLIB, which has a similar purpose/name to the LLVM_BUILD_LLVM_C_DYLIB option.
* On all platforms, this will work with both static, BUILD_SHARED_LIBS, and libMLIR builds, if supported:
  * In static builds: libMLIR-C.so will export the CAPI symbols and statically link all dependencies into itself.
  * In BUILD_SHARED_LIBS: libMLIR-C.so will export the CAPI symbols and have dynamic dependencies on implementation shared libraries.
  * In libMLIR.so mode: same as static. libMLIR.so was not finished for actual linking use within the project. An eventual relayering so that libMLIR-C.so depends on libMLIR.so is possible but requires first re-engineering the latter to use the aggregate facility.
* On Linux, exported symbols are filtered to only the CAPI. On others (MacOS, Windows), all symbols are exported. A CMake status is printed unless if global visibility is hidden indicating that this has not yet been implemented. The library should still work, but it will be larger and more likely to conflict until fixed. Someone should look at lifting the corresponding support from libLLVM-C.so and adapting. Or, for special uses, just build with `-DCMAKE_CXX_VISIBILITY_PRESET=hidden -DCMAKE_C_VISIBILITY_PRESET=hidden`.
* Includes fixes to execution engine symbol export macros to enable default visibility. Without this, the advice to use hidden visibility would have resulted in test failures and unusable execution engine support libraries.

Differential Revision: https://reviews.llvm.org/D113731

diff --git a/mlir/CMakeLists.txt b/mlir/CMakeLists.txt
index 58dc116..6be0b35 100644 (file)
--- a/mlir/CMakeLists.txt
+++ b/mlir/CMakeLists.txt
@@ -96,6 +96,8 @@ set(MLIR_INSTALL_AGGREGATE_OBJECTS 1 CACHE BOOL
     not desired. Enabling this will result in object files being written \
     under lib/objects-{CMAKE_BUILD_TYPE}.")
 
+set(MLIR_BUILD_MLIR_C_DYLIB 0 CACHE BOOL "Builds libMLIR-C shared library.")
+
 #-------------------------------------------------------------------------------
 # Python Bindings Configuration
 # Requires:

diff --git a/mlir/include/mlir/ExecutionEngine/CRunnerUtils.h b/mlir/include/mlir/ExecutionEngine/CRunnerUtils.h
index bd855fc..3baff4c 100644 (file)
--- a/mlir/include/mlir/ExecutionEngine/CRunnerUtils.h
+++ b/mlir/include/mlir/ExecutionEngine/CRunnerUtils.h
@@ -27,7 +27,8 @@
 #endif // mlir_c_runner_utils_EXPORTS
 #endif // MLIR_CRUNNERUTILS_EXPORT
 #else  // _WIN32
-#define MLIR_CRUNNERUTILS_EXPORT
+// Non-windows: use visibility attributes.
+#define MLIR_CRUNNERUTILS_EXPORT __attribute__((visibility("default")))
 #define MLIR_CRUNNERUTILS_DEFINE_FUNCTIONS
 #endif // _WIN32
 

diff --git a/mlir/include/mlir/ExecutionEngine/RunnerUtils.h b/mlir/include/mlir/ExecutionEngine/RunnerUtils.h
index 9d612c1..1fb39ee 100644 (file)
--- a/mlir/include/mlir/ExecutionEngine/RunnerUtils.h
+++ b/mlir/include/mlir/ExecutionEngine/RunnerUtils.h
@@ -27,7 +27,8 @@
 #endif // mlir_runner_utils_EXPORTS
 #endif // MLIR_RUNNERUTILS_EXPORT
 #else
-#define MLIR_RUNNERUTILS_EXPORT
+// Non-windows: use visibility attributes.
+#define MLIR_RUNNERUTILS_EXPORT __attribute__((visibility("default")))
 #endif // _WIN32
 
 #include <assert.h>

diff --git a/mlir/lib/CAPI/CMakeLists.txt b/mlir/lib/CAPI/CMakeLists.txt
index 30ccbe9..5545de6 100644 (file)
--- a/mlir/lib/CAPI/CMakeLists.txt
+++ b/mlir/lib/CAPI/CMakeLists.txt
@@ -1,3 +1,12 @@
+# For upstream, we accumulate all libraries into the MLIR_CAPI_LIBRARIES
+# property via a custom wrapper function. This is then used to create an
+# aggregate below.
+set_property(GLOBAL APPEND PROPERTY MLIR_CAPI_LIBRARIES)
+function(add_mlir_upstream_c_api_library name)
+  add_mlir_public_c_api_library(${name} ${ARGN})
+  set_property(GLOBAL APPEND PROPERTY MLIR_CAPI_LIBRARIES ${name})
+endfunction()
+
 add_subdirectory(Debug)
 add_subdirectory(Dialect)
 add_subdirectory(Conversion)
@@ -6,3 +15,21 @@ add_subdirectory(Interfaces)
 add_subdirectory(IR)
 add_subdirectory(Registration)
 add_subdirectory(Transforms)
+
+# Build the optional CAPI dylib.
+if(MLIR_BUILD_MLIR_C_DYLIB)
+  message(STATUS "Building MLIR-C dylib")
+  get_property(_capi_libraries GLOBAL PROPERTY MLIR_CAPI_LIBRARIES)
+  add_mlir_aggregate(MLIR-C
+    SHARED
+    EMBED_LIBS
+      ${_capi_libraries}
+  )
+  if(CMAKE_SYSTEM_NAME STREQUAL "Linux")
+    target_link_options(MLIR-C PRIVATE "-Wl,-exclude-libs,ALL")
+  else()
+    if(NOT CMAKE_C_VISIBILITY_PRESET STREQUAL "hidden" OR NOT CMAKE_CXX_VISIBILITY_PRESET STREQUAL "hidden")
+      message(STATUS "MLIR-C on this platform exports all symbols. Recommend building with CMAKE_(C|CXX)_VISIBILITY_PRESET=hidden or implement filtering support.")
+    endif()
+  endif()
+endif()

diff --git a/mlir/lib/CAPI/Conversion/CMakeLists.txt b/mlir/lib/CAPI/Conversion/CMakeLists.txt
index 83435cd..166e799 100644 (file)
--- a/mlir/lib/CAPI/Conversion/CMakeLists.txt
+++ b/mlir/lib/CAPI/Conversion/CMakeLists.txt
@@ -1,5 +1,5 @@
 get_property(conversion_libs GLOBAL PROPERTY MLIR_CONVERSION_LIBS)
-add_mlir_public_c_api_library(MLIRCAPIConversion
+add_mlir_upstream_c_api_library(MLIRCAPIConversion
   Passes.cpp
 
   LINK_LIBS PUBLIC

diff --git a/mlir/lib/CAPI/Debug/CMakeLists.txt b/mlir/lib/CAPI/Debug/CMakeLists.txt
index fdffe30..7b32f3a 100644 (file)
--- a/mlir/lib/CAPI/Debug/CMakeLists.txt
+++ b/mlir/lib/CAPI/Debug/CMakeLists.txt
@@ -1,4 +1,4 @@
-add_mlir_public_c_api_library(MLIRCAPIDebug
+add_mlir_upstream_c_api_library(MLIRCAPIDebug
   Debug.cpp
 
   LINK_LIBS PUBLIC

diff --git a/mlir/lib/CAPI/Dialect/CMakeLists.txt b/mlir/lib/CAPI/Dialect/CMakeLists.txt
index 801b0f7..4f11bc5 100644 (file)
--- a/mlir/lib/CAPI/Dialect/CMakeLists.txt
+++ b/mlir/lib/CAPI/Dialect/CMakeLists.txt
@@ -1,4 +1,4 @@
-add_mlir_public_c_api_library(MLIRCAPIAsync
+add_mlir_upstream_c_api_library(MLIRCAPIAsync
   Async.cpp
   AsyncPasses.cpp
 
@@ -13,7 +13,7 @@ add_mlir_public_c_api_library(MLIRCAPIAsync
   MLIRPass
 )
 
-add_mlir_public_c_api_library(MLIRCAPIGPU
+add_mlir_upstream_c_api_library(MLIRCAPIGPU
   GPU.cpp
   GPUPasses.cpp
 
@@ -27,7 +27,7 @@ add_mlir_public_c_api_library(MLIRCAPIGPU
   MLIRPass
 )
 
-add_mlir_public_c_api_library(MLIRCAPILLVM
+add_mlir_upstream_c_api_library(MLIRCAPILLVM
   LLVM.cpp
 
   PARTIAL_SOURCES_INTENDED
@@ -36,7 +36,7 @@ add_mlir_public_c_api_library(MLIRCAPILLVM
   MLIRLLVMIR
 )
 
-add_mlir_public_c_api_library(MLIRCAPILinalg
+add_mlir_upstream_c_api_library(MLIRCAPILinalg
   Linalg.cpp
   LinalgPasses.cpp
 
@@ -51,7 +51,7 @@ add_mlir_public_c_api_library(MLIRCAPILinalg
   MLIRLinalgTransforms
 )
 
-add_mlir_public_c_api_library(MLIRCAPISCF
+add_mlir_upstream_c_api_library(MLIRCAPISCF
   SCF.cpp
 
   PARTIAL_SOURCES_INTENDED
@@ -60,7 +60,7 @@ add_mlir_public_c_api_library(MLIRCAPISCF
   MLIRSCF
 )
 
-add_mlir_public_c_api_library(MLIRCAPIShape
+add_mlir_upstream_c_api_library(MLIRCAPIShape
   Shape.cpp
 
   PARTIAL_SOURCES_INTENDED
@@ -69,7 +69,7 @@ add_mlir_public_c_api_library(MLIRCAPIShape
   MLIRShape
 )
 
-add_mlir_public_c_api_library(MLIRCAPISparseTensor
+add_mlir_upstream_c_api_library(MLIRCAPISparseTensor
   SparseTensor.cpp
   SparseTensorPasses.cpp
 
@@ -80,7 +80,7 @@ add_mlir_public_c_api_library(MLIRCAPISparseTensor
   MLIRSparseTensorTransforms
 )
 
-add_mlir_public_c_api_library(MLIRCAPIStandard
+add_mlir_upstream_c_api_library(MLIRCAPIStandard
   Standard.cpp
 
   PARTIAL_SOURCES_INTENDED
@@ -89,7 +89,7 @@ add_mlir_public_c_api_library(MLIRCAPIStandard
   MLIRStandard
 )
 
-add_mlir_public_c_api_library(MLIRCAPITensor
+add_mlir_upstream_c_api_library(MLIRCAPITensor
   Tensor.cpp
 
   PARTIAL_SOURCES_INTENDED

diff --git a/mlir/lib/CAPI/ExecutionEngine/CMakeLists.txt b/mlir/lib/CAPI/ExecutionEngine/CMakeLists.txt
index 09dcb61..0c28e7e 100644 (file)
--- a/mlir/lib/CAPI/ExecutionEngine/CMakeLists.txt
+++ b/mlir/lib/CAPI/ExecutionEngine/CMakeLists.txt
@@ -1,5 +1,5 @@
 # Main API shared library.
-add_mlir_public_c_api_library(MLIRCEXECUTIONENGINE
+add_mlir_upstream_c_api_library(MLIRCEXECUTIONENGINE
   ExecutionEngine.cpp
 
   LINK_LIBS PUBLIC

diff --git a/mlir/lib/CAPI/IR/CMakeLists.txt b/mlir/lib/CAPI/IR/CMakeLists.txt
index 486ba6e..320ed07 100644 (file)
--- a/mlir/lib/CAPI/IR/CMakeLists.txt
+++ b/mlir/lib/CAPI/IR/CMakeLists.txt
@@ -1,5 +1,5 @@
 # Main API shared library.
-add_mlir_public_c_api_library(MLIRCAPIIR
+add_mlir_upstream_c_api_library(MLIRCAPIIR
   AffineExpr.cpp
   AffineMap.cpp
   BuiltinAttributes.cpp

diff --git a/mlir/lib/CAPI/Interfaces/CMakeLists.txt b/mlir/lib/CAPI/Interfaces/CMakeLists.txt
index 1de5f21..7aefb56 100644 (file)
--- a/mlir/lib/CAPI/Interfaces/CMakeLists.txt
+++ b/mlir/lib/CAPI/Interfaces/CMakeLists.txt
@@ -1,4 +1,4 @@
-add_mlir_public_c_api_library(MLIRCAPIInterfaces
+add_mlir_upstream_c_api_library(MLIRCAPIInterfaces
   Interfaces.cpp
 
   LINK_LIBS PUBLIC

diff --git a/mlir/lib/CAPI/Registration/CMakeLists.txt b/mlir/lib/CAPI/Registration/CMakeLists.txt
index b4a8650..67e26a5 100644 (file)
--- a/mlir/lib/CAPI/Registration/CMakeLists.txt
+++ b/mlir/lib/CAPI/Registration/CMakeLists.txt
@@ -2,7 +2,7 @@
 get_property(dialect_libs GLOBAL PROPERTY MLIR_DIALECT_LIBS)
 get_property(translation_libs GLOBAL PROPERTY MLIR_TRANSLATION_LIBS)
 get_property(conversion_libs GLOBAL PROPERTY MLIR_CONVERSION_LIBS)
-add_mlir_public_c_api_library(MLIRCAPIRegistration
+add_mlir_upstream_c_api_library(MLIRCAPIRegistration
   Registration.cpp
 
   LINK_LIBS PUBLIC

diff --git a/mlir/lib/CAPI/Transforms/CMakeLists.txt b/mlir/lib/CAPI/Transforms/CMakeLists.txt
index e5e1677..2638025 100644 (file)
--- a/mlir/lib/CAPI/Transforms/CMakeLists.txt
+++ b/mlir/lib/CAPI/Transforms/CMakeLists.txt
@@ -1,4 +1,4 @@
-add_mlir_public_c_api_library(MLIRCAPITransforms
+add_mlir_upstream_c_api_library(MLIRCAPITransforms
   Passes.cpp
 
   LINK_LIBS PUBLIC

diff --git a/mlir/test/CAPI/CMakeLists.txt b/mlir/test/CAPI/CMakeLists.txt
index 25653ce..43c22e5 100644 (file)
--- a/mlir/test/CAPI/CMakeLists.txt
+++ b/mlir/test/CAPI/CMakeLists.txt
@@ -10,8 +10,13 @@ function(_add_capi_test_executable name)
     PARTIAL_SOURCES_INTENDED
     ${ARG_UNPARSED_ARGUMENTS})
   llvm_update_compile_flags(${name})
-  target_link_libraries(${name}
-    ${ARG_LINK_LIBS})
+  if(MLIR_BUILD_MLIR_C_DYLIB)
+    target_link_libraries(${name} PRIVATE
+      MLIR-C)
+  else()
+    target_link_libraries(${name} PRIVATE
+      ${ARG_LINK_LIBS})
+  endif()
 endfunction(_add_capi_test_executable)
 
 _add_capi_test_executable(mlir-capi-execution-engine-test