[llvm] [BOLT] Enable standalone build (PR #87196)

[via llvm-commits]

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@@ -7,6 +18,137 @@ set(CMAKE_CXX_STANDARD 17)
 # Add path for custom modules.
 list(INSERT CMAKE_MODULE_PATH 0 "${BOLT_SOURCE_DIR}/cmake/modules")
 
+# standalone build, copied from clang
+if(BOLT_BUILT_STANDALONE)
+  set(CMAKE_CXX_STANDARD 17 CACHE STRING "C++ standard to conform to")
+  set(CMAKE_CXX_STANDARD_REQUIRED YES)
+  set(CMAKE_CXX_EXTENSIONS NO)
+
+  if(NOT MSVC_IDE)
+    set(LLVM_ENABLE_ASSERTIONS ${ENABLE_ASSERTIONS}
+      CACHE BOOL "Enable assertions")
+    # Assertions should follow llvm-config's.
+    mark_as_advanced(LLVM_ENABLE_ASSERTIONS)
+  endif()
+
+  find_package(LLVM REQUIRED HINTS "${LLVM_CMAKE_DIR}")
+  list(APPEND CMAKE_MODULE_PATH "${LLVM_DIR}")
+
+  # Turn into CACHE PATHs for overwritting
+
+  # We can't check LLVM_CONFIG here, because find_package(LLVM ...) also sets
+  # LLVM_CONFIG.
+  if (NOT LLVM_CONFIG_FOUND)
+    # Pull values from LLVMConfig.cmake.  We can drop this once the llvm-config
+    # path is removed.
+    set(INCLUDE_DIRS ${LLVM_INCLUDE_DIRS})
+    set(LLVM_OBJ_DIR "${LLVM_BINARY_DIR}")
+    # N.B. this is just a default value, the CACHE PATHs below can be overridden.
+    set(MAIN_SRC_DIR "${CMAKE_CURRENT_SOURCE_DIR}/../llvm")
+  else()
+    set(INCLUDE_DIRS "${LLVM_BINARY_DIR}/include" "${MAIN_INCLUDE_DIR}")
+  endif()
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pca006132 wrote:

thanks!

https://github.com/llvm/llvm-project/pull/87196