From 7381df3bdd9e1f654fa424e19b285de7922c1a8b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Dan=20=C4=8Cerm=C3=A1k?= <dcermak@suse.com>
Date: Fri, 1 Nov 2019 10:02:57 +0100
Subject: [PATCH] Fix builds for LLVM 9 (for LLVM build without
 BUILD_SHARED_LIBS=ON)

LLVM 9 officially ships the C++ libraries as a single library
libclang-cpp.so. This makes ccls fail to link as the individual libraries
libclangIndex, libclangFormat, etc. are no longer present.

We use clang-cpp if it is available and fallback to the previously used
behavior if clang-cpp is not available.
---
 CMakeLists.txt | 40 +++++++++++++++++++++++++---------------
 1 file changed, 25 insertions(+), 15 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 278e0735..fe6f8f70 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -68,23 +68,33 @@ endif()
 
 ### Libraries
 
+# LLVM >= 9 ships the C++ libraries by default in a single library libclang-cpp,
+# but this is not universally enabled on all distributions.
+# If clang-cpp is available, then link against it, otherwise link against the
+# individual clang libraries.
 find_package(Clang REQUIRED)
 
-target_link_libraries(ccls PRIVATE
-  clangIndex
-  clangFormat
-  clangTooling
-  clangToolingInclusions
-  clangToolingCore
-  clangFrontend
-  clangParse
-  clangSerialization
-  clangSema
-  clangAST
-  clangLex
-  clangDriver
-  clangBasic
-)
+if(TARGET clang-cpp AND NOT TARGET clangBasic)
+  target_link_libraries(ccls PRIVATE
+    clang-cpp
+    )
+else()
+  target_link_libraries(ccls PRIVATE
+    clangIndex
+    clangFormat
+    clangTooling
+    clangToolingInclusions
+    clangToolingCore
+    clangFrontend
+    clangParse
+    clangSerialization
+    clangSema
+    clangAST
+    clangLex
+    clangDriver
+    clangBasic
+    )
+endif()
 
 if(LLVM_LINK_LLVM_DYLIB)
   target_link_libraries(ccls PRIVATE LLVM)