Support standalone builds of the offload test suite

CMakeLists.txt

@@ -1,7 +1,70 @@
 # This project is only buildable as a subproject of LLVM.
+cmake_minimum_required(VERSION 3.31.0)
 
 project(OffloadTest)
 
+# If we are not building as a part of LLVM, build Clang as an
+# standalone project, using LLVM as an external library:
+if(CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR)
+  set(OFFLOADTEST_BUILT_STANDALONE TRUE)
+endif()
+
+if (OFFLOADTEST_BUILT_STANDALONE)
+  find_package(LLVM REQUIRED HINTS "${LLVM_CMAKE_DIR}")
+  list(APPEND CMAKE_MODULE_PATH "${LLVM_DIR}")
+
+  include(AddLLVM)
+
+  find_package(Python3 ${LLVM_MINIMUM_PYTHON_VERSION} REQUIRED
+    COMPONENTS Interpreter)
+
+  set(CMAKE_CXX_STANDARD 17 CACHE STRING "C++ standard to conform to")
+  set(CMAKE_CXX_STANDARD_REQUIRED YES)
+  set(CMAKE_CXX_EXTENSIONS NO)
+
+  # They are used as destination of target generators.
+  set(LLVM_RUNTIME_OUTPUT_INTDIR ${CMAKE_BINARY_DIR}/${CMAKE_CFG_INTDIR}/bin)
+  set(LLVM_LIBRARY_OUTPUT_INTDIR ${CMAKE_BINARY_DIR}/${CMAKE_CFG_INTDIR}/lib${LLVM_LIBDIR_SUFFIX})
+  if(WIN32 OR CYGWIN)
+    # DLL platform -- put DLLs into bin.
+    set(LLVM_SHLIB_OUTPUT_INTDIR ${LLVM_RUNTIME_OUTPUT_INTDIR})
+  else()
+    set(LLVM_SHLIB_OUTPUT_INTDIR ${LLVM_LIBRARY_OUTPUT_INTDIR})
+  endif()
+
+  set(LLVM_TOOLS_DIR ${LLVM_TOOLS_BINARY_DIR})
+  include_directories(${LLVM_INCLUDE_DIRS})
+  link_directories("${LLVM_LIBRARY_DIR}")
+
+  if (NOT LLVM_MAIN_SRC_DIR OR NOT EXISTS "${LLVM_MAIN_SRC_DIR}")
+    message(FATAL_ERROR "LLVM_MAIN_SRC_DIR is not set or invalid. Please set it to the root of the LLVM source tree.")
+  endif()
+
+  # Seek installed Lit.
+  find_program(LLVM_LIT
+                NAMES llvm-lit lit.py lit
+                PATHS "${LLVM_MAIN_SRC_DIR}/utils/lit"
+                DOC "Path to lit.py")
+
+  if(EXISTS ${LLVM_MAIN_SRC_DIR}/utils/lit/lit.py)
+        # Note: path not really used, except for checking if lit was found
+  if(EXISTS ${LLVM_MAIN_SRC_DIR}/utils/llvm-lit)
+    add_subdirectory(${LLVM_MAIN_SRC_DIR}/utils/llvm-lit utils/llvm-lit)
+  endif()
+  endif()
+
+  if (NOT LLVM_THIRD_PARTY_DIR)
+    set(LLVM_THIRD_PARTY_DIR "${LLVM_MAIN_SRC_DIR}/../third-party")
+  endif()
+  if (NOT TARGET llvm_gtest)
+      add_subdirectory(${LLVM_THIRD_PARTY_DIR}/unittest ${CMAKE_CURRENT_BINARY_DIR}/third-party/unittest)
+  endif()
+endif()
+
+# Setting this allows the offload-test-suite to have a separate tools directory
+# from the llvm-provided tools.
+set(OFFLOADTEST_TOOLS_DIR ${LLVM_RUNTIME_OUTPUT_INTDIR})
+
 # Add path for custom modules
 list(INSERT CMAKE_MODULE_PATH 0
   "${CMAKE_CURRENT_SOURCE_DIR}/cmake"

cmake/caches/OffloadDistribution.cmake

@@ -0,0 +1,39 @@
+# Including the native target is important because some of LLVM's tests fail if
+# you don't.
+set(LLVM_TARGETS_TO_BUILD "Native;SPIRV" CACHE STRING "")
+
+# Include the DirectX target for DXIL code generation.
+set(LLVM_EXPERIMENTAL_TARGETS_TO_BUILD "DirectX" CACHE STRING "")
+
+set(LLVM_ENABLE_PROJECTS "clang;clang-tools-extra" CACHE STRING "")
+
+set(CLANG_ENABLE_HLSL On CACHE BOOL "")
+
+set(LLVM_INSTALL_UTILS ON CACHE BOOL "")
+set(LLVM_INSTALL_TOOLCHAIN_ONLY OFF CACHE BOOL "")
+set(LLVM_DISTRIBUTION_COMPONENTS
+    clang
+    hlsl-resource-headers
+    FileCheck
+    split-file
+    obj2yaml
+    not
+    llvm-headers
+    LLVMSupport
+    LLVMDemangle   # Dependency of LLVMSupport
+    LLVMObject
+    # Dependencies of LLVMObject
+    LLVMBitReader
+    LLVMBitstreamReader # Dependency of LLVMBitReader
+    LLVMCore
+    LLVMRemarks # Dependency of LLVMCore
+    LLVMMC
+    LLVMDebugInfoDWARFLowLevel # Dependency of LLVMMC
+    LLVMIRReader
+    LLVMAsmParser # Dependency of LLVMIRReader
+    LLVMBinaryFormat
+    LLVMMCParser
+    LLVMTargetParser
+    LLVMTextAPI
+    cmake-exports
+    CACHE STRING "")

cmake/caches/StandaloneDistribution.cmake

@@ -0,0 +1,39 @@
+# Including the native target is important because some of LLVM's tests fail if
+# you don't.
+set(LLVM_TARGETS_TO_BUILD "Native;SPIRV" CACHE STRING "")
+
+# Include the DirectX target for DXIL code generation.
+set(LLVM_EXPERIMENTAL_TARGETS_TO_BUILD "DirectX" CACHE STRING "")
+
+set(LLVM_ENABLE_PROJECTS "clang;clang-tools-extra" CACHE STRING "")
+
+set(CLANG_ENABLE_HLSL On CACHE BOOL "")
+
+set(LLVM_INSTALL_UTILS ON CACHE BOOL "")
+set(LLVM_INSTALL_TOOLCHAIN_ONLY OFF CACHE BOOL "")
+set(LLVM_DISTRIBUTION_COMPONENTS
+    clang
+    hlsl-resource-headers
+    FileCheck
+    split-file
+    obj2yaml
+    not
+    llvm-headers
+    LLVMSupport
+    LLVMDemangle   # Dependency of LLVMSupport
+    LLVMObject
+    # Dependencies of LLVMObject
+    LLVMBitReader
+    LLVMBitstreamReader # Dependency of LLVMBitReader
+    LLVMCore
+    LLVMRemarks # Dependency of LLVMCore
+    LLVMMC
+    LLVMDebugInfoDWARFLowLevel # Dependency of LLVMMC
+    LLVMIRReader
+    LLVMAsmParser # Dependency of LLVMIRReader
+    LLVMBinaryFormat
+    LLVMMCParser
+    LLVMTargetParser
+    LLVMTextAPI
+    cmake-exports
+    CACHE STRING "")

docs/offload-distribution.md

@@ -185,3 +185,44 @@ The reusable workflow `.github/workflows/build-and-test-callable.yaml`
 implements this flow when invoked with `SplitBuild=true`. The build job
 produces two artifacts (`build-<sku>-<target>` and `dxc-<sku>-<target>`)
 and the test job consumes both.
+
+## Standalone Build Distribution
+
+An alternate approach for separating the build and test flow in the offload test
+suite is using the "standalone" build mode. With this build flow, LLVM (and
+optionally Clang) are built separately from the offload-test suite, and the
+offload-test-suite is configured as the top-level CMake entry.
+
+A sample configuration for this flow is provided in the
+`cmake/caches/StandaloneDistribution.cmake` cache script. In this build
+configuration, the LLVM build contributes Clang, the llvm testing tools, and the
+subset of LLVM component libraries that the offload-test-suite's tools depend
+on.
+
+Using this flow LLVM and Clang are configured using a command like:
+
+```
+cmake -C <offload test>/cmake/caches/StandaloneDistribution.cmake \
+      -DCMAKE_INSTALL_PREFIX=<path to install to>                 \
+      <other cmake options> <path to llvm>
+ninja install-distribution
+```
+
+Then configure and build the offload test suite with a command like so:
+
+```
+cmake -DCMAKE_PREFIX_PATH=<path to llvm install>/lib/cmake/llvm \
+      -DLLVM_MAIN_SRC_DIR=<path to llvm-project>/llvm           \
+      -DDXC_DIR=<path to folder containing dxc/dxv>             \
+      -DOFFLOAD_TEST_TEST_CLANG=On                              \
+      -DGOLDENIMAGE_DIR=<path to images>                        \
+      <other cmake options> <path to ofload test suite>
+ninja check-hlsl
+```
+
+In this configuration the offload-test-suite will build its tools against the
+already built LLVM libraries which dramatically reduces build time. This
+configuration does still require a checkout of the LLVM source tree to pull LIT
+and the third-party unit testing libraries. If clone/checkout time or disk space
+is a concern this could be a sparse checkout or future changes could allow this
+to use LIT from pip and a stock googletest framework.

lib/API/DX/Device.cpp

@@ -36,6 +36,7 @@
 #include "API/Encoder.h"
 #include "API/FormatConversion.h"
 #include "DXFeatures.h"
+#include "Support/OffloadMigration.h"
 #include "Support/Pipeline.h"
 #include "Support/WinError.h"
 
@@ -50,8 +51,6 @@
 
 #include "../Util.h"
 
-#include "../Support/OffloadMigration.h"
-
 #include <atomic>
 #include <codecvt>
 #include <locale>

lib/Support/OffloadMigration.cpp

@@ -1,4 +1,4 @@
-#include "OffloadMigration.h"
+#include "Support/OffloadMigration.h"
 
 #include "API/Device.h"
 #include "API/FormatConversion.h"

test/CMakeLists.txt

@@ -67,7 +67,7 @@ list(APPEND OFFLOADTEST_DEPS
   obj2yaml
   not)
 
-if (OFFLOADTEST_TEST_CLANG)
+if (OFFLOADTEST_TEST_CLANG AND NOT OFFLOADTEST_BUILT_STANDALONE)
   list(APPEND OFFLOADTEST_DEPS clang)
 endif()
 

test/lit.cfg.py

@@ -41,6 +41,8 @@
 # Tweak the PATH to include the tools dir.
 llvm_config.with_environment("PATH", config.llvm_tools_dir, append_path=True)
 
+tool_dirs = [config.llvm_tools_dir, config.offloadtest_tools_dir]
+
 
 llvm_config.with_system_environment(
     [
@@ -329,9 +331,9 @@ def setDeviceFeatures(config, device, compiler):
 
 tools.append(ToolSubst("obj2yaml", FindTool("obj2yaml")))
 
-llvm_config.add_tool_substitutions(tools, config.llvm_tools_dir)
+llvm_config.add_tool_substitutions(tools, tool_dirs)
 
-api_query = os.path.join(config.llvm_tools_dir, "api-query")
+api_query = os.path.join(config.offloadtest_tools_dir, "api-query")
 query_string = subprocess.check_output(api_query)
 devices = yaml.safe_load(query_string)
 target_device = None

test/lit.site.cfg.py.in

@@ -4,6 +4,7 @@ import sys
 
 config.offloadtest_obj_root = path(r"@OFFLOADTEST_BINARY_DIR@")
 config.offloadtest_src_root = path(r"@OFFLOADTEST_TEST_ROOT@")
+config.offloadtest_tools_dir = lit_config.substitute(path(r"@OFFLOADTEST_TOOLS_DIR@"))
 config.llvm_tools_dir = lit_config.substitute(path(r"@LLVM_TOOLS_DIR@"))
 config.offloadtest_dxc = '"' + path(r"@DXC_EXECUTABLE@") + '"'
 config.offloadtest_supports_spirv = @SUPPORTS_SPIRV@

utils/configure-test-suite.py

@@ -244,6 +244,7 @@ def main():
             # layout it's the install share dir.
             "OFFLOADTEST_TEST_ROOT": str(test_src_root.parent),
             "LLVM_TOOLS_DIR": str(bin_dir),
+            "OFFLOADTEST_TOOLS_DIR": str(bin_dir),
             "DXC_EXECUTABLE": str(dxc_path) if dxc_path is not None else "",
             "SUPPORTS_SPIRV": "True" if vk else "False",
             "FORCE_CLANG": "True" if clang else "False",