From d3c20f45f3cc2396db277dad58611d8d450fc5d5 Mon Sep 17 00:00:00 2001
From: Fangrui Song <i@maskray.me>
Date: Sat, 16 Jan 2021 11:14:19 -0800
Subject: [PATCH] Build: Simplify CMAKE_PREFIX_PATH

---
 Build.md | 29 ++++++++++++-----------------
 1 file changed, 12 insertions(+), 17 deletions(-)

diff --git a/Build.md b/Build.md
index 75cb4fe..2c116b9 100644
--- a/Build.md
+++ b/Build.md
@@ -93,7 +93,9 @@ for your system, as well as methods of obtaining and locating Clang+LLVM.
 * `-DCMAKE_PREFIX_PATH=<path>`
 
   Specify paths where CMake can locate Clang/LLVM headers and libraries.
-  CMake searches the paths in `CMAKE_PREFIX_PATH` for `include` and `lib`.
+  CMake searches the paths in `CMAKE_PREFIX_PATH` for
+  `lib/cmake/clang/ClangConfig.cmake`, `lib/cmake/llvm/LLVMConfig.cmake`,
+  `include` and `lib`.
 
 * `-DUSE_SYSTEM_RAPIDJSON=(ON|OFF)`
 
@@ -288,7 +290,7 @@ ninja -C Release clangFormat clangFrontendTool clangIndex clangTooling clang
 
 # Download ccls
 cd ccls
-cmake -H. -BRelease -G Ninja -DCMAKE_BUILD_TYPE=Release -DCMAKE_CXX_COMPILER=clang-cl -DCMAKE_PREFIX_PATH="D:/llvm/Release;D:/llvm/Release/tools/clang;D:/llvm;D:/llvm/tools/clang"
+cmake -H. -BRelease -G Ninja -DCMAKE_BUILD_TYPE=Release -DCMAKE_CXX_COMPILER=clang-cl -DCMAKE_PREFIX_PATH="D:/llvm/Release"
 ninja -C Release
 ```
 
@@ -324,30 +326,23 @@ Then build ccls with `-DCMAKE_PREFIX_PATH`:
 ```sh
 cd ~/ccls
 LLVM=$HOME/llvm-project
-cmake -H. -BRelease -G Ninja -DCMAKE_BUILD_TYPE=Release -DCMAKE_CXX_COMPILER=clang++ -DCMAKE_EXE_LINKER_FLAGS=-fuse-ld=lld -DCMAKE_PREFIX_PATH="$LLVM/Release;$LLVM/llvm;$LLVM/clang"
+cmake -H. -BRelease -G Ninja -DCMAKE_BUILD_TYPE=Release -DCMAKE_CXX_COMPILER=clang++ -DCMAKE_EXE_LINKER_FLAGS=-fuse-ld=lld -DCMAKE_PREFIX_PATH="$LLVM/Release"
 ninja -C Release
 ```
 
-`-DCMAKE_PREFIX_PATH=` is a `;`-separated list where you can find:
-
-* `llvm`: llvm source
-* `llvm/tools/clang`: clang source
-* `llvm/Release`: build directory. `include/` contains generated llvm header files, e.g. `include/llvm/Config/config.h`
-* `llvm/Release/tools/clang`: build directory. `include/` contains generated clang header files, e.g. `include/clang/Config/config.h`
-
-The cmake build system is expected to find these files:
+`-DCMAKE_PREFIX_PATH=` is a `;`-separated list. The cmake build system is expected to find these files:
 
 ```
 # generated clang+llvm header files
-~/llvm/Release/include/llvm/Config/config.h
-~/llvm/Release/tools/clang/include/clang/Config/config.h
+include/llvm/Config/config.h
+tools/clang/include/clang/Config/config.h
 # libclangIndex.so
-~/llvm/Release/lib/libclangIndex.so or libclangIndex.a
+lib/libclangIndex.so or libclangIndex.a
 # -resource-dir
-~/llvm/Release/lib/clang/7.0.0
+lib/clang/7.0.0
 # clang+llvm libraries
-~/llvm/Release/lib/libclangDriver.so
-~/llvm/Release/lib/libLLVMSupport.so or libLLVMSupport.a
+lib/libclangDriver.so
+lib/libLLVMSupport.so or libLLVMSupport.a
 ...
 ```