[llvm] e6c7ed6 - build: make `LLVM_ENABLE_ZLIB` a tri-bool for users

[Saleem Abdulrasool via llvm-commits]

Author: Saleem Abdulrasool
Date: 2020-01-01T17:02:16-08:00
New Revision: e6c7ed6d2164a0659fd9f6ee44f1375d301e3cad

URL: https://github.com/llvm/llvm-project/commit/e6c7ed6d2164a0659fd9f6ee44f1375d301e3cad
DIFF: https://github.com/llvm/llvm-project/commit/e6c7ed6d2164a0659fd9f6ee44f1375d301e3cad.diff

LOG: build: make `LLVM_ENABLE_ZLIB` a tri-bool for users

Treat the flag `LLVM_ENABLE_ZLIB` as a tri-bool, `FORCE_ON` being `ON`,
and `ON` being an auto-detect.  This is needed as many of the builders
enable the flag without having zlib available.

Added: 
    

Modified: 
    llvm/CMakeLists.txt
    llvm/cmake/config-ix.cmake
    llvm/lib/Support/CMakeLists.txt

Removed: 
    


################################################################################
diff  --git a/llvm/CMakeLists.txt b/llvm/CMakeLists.txt
index eeac7bab850a..05e93f67e990 100644
--- a/llvm/CMakeLists.txt
+++ b/llvm/CMakeLists.txt
@@ -347,7 +347,7 @@ option(LLVM_ENABLE_LIBPFM "Use libpfm for performance counters if available." ON
 
 option(LLVM_ENABLE_THREADS "Use threads if available." ON)
 
-option(LLVM_ENABLE_ZLIB "Use zlib for compression/decompression if available." ON)
+set(LLVM_ENABLE_ZLIB "ON" CACHE STRING "Use zlib for compression/decompression if available. Can be ON, OFF, or FORCE_ON")
 
 set(LLVM_Z3_INSTALL_DIR "" CACHE STRING "Install directory of the Z3 solver.")
 

diff  --git a/llvm/cmake/config-ix.cmake b/llvm/cmake/config-ix.cmake
index d5a15a680a6d..a16038f70989 100644
--- a/llvm/cmake/config-ix.cmake
+++ b/llvm/cmake/config-ix.cmake
@@ -117,10 +117,6 @@ endif()
 # Don't look for these libraries if we're using MSan, since uninstrumented third
 # party code may call MSan interceptors like strlen, leading to false positives.
 if(NOT LLVM_USE_SANITIZER MATCHES "Memory.*")
-  if(LLVM_ENABLE_ZLIB)
-    find_package(ZLIB REQUIRED)
-  endif()
-
   # Don't look for these libraries on Windows.
   if (NOT PURE_WINDOWS)
     # Skip libedit if using ASan as it contains memory leaks.
@@ -506,7 +502,21 @@ else( LLVM_ENABLE_THREADS )
 endif()
 
 if(LLVM_ENABLE_ZLIB)
-  find_package(ZLIB REQUIRED)
+  if(LLVM_ENABLE_ZLIB STREQUAL FORCE_ON)
+    find_package(ZLIB REQUIRED)
+  else()
+    find_package(ZLIB)
+  endif()
+
+  if(ZLIB_FOUND)
+    set(LLVM_ENABLE_ZLIB "YES" CACHE STRING
+      "Use zlib for compression/decompression if available. Can be ON, OFF, or FORCE_ON"
+      FORCE)
+  else()
+    set(LLVM_ENABLE_ZLIB "NO" CACHE STRING
+      "Use zlib for compression/decompression if available. Can be ON, OFF, or FORCE_ON"
+      FORCE)
+  endif()
 endif()
 
 if (LLVM_ENABLE_DOXYGEN)

diff  --git a/llvm/lib/Support/CMakeLists.txt b/llvm/lib/Support/CMakeLists.txt
index 2fa641ff5da3..26332d4f539c 100644
--- a/llvm/lib/Support/CMakeLists.txt
+++ b/llvm/lib/Support/CMakeLists.txt
@@ -1,4 +1,7 @@
-set(system_libs ${ZLIB_LIBRARY})
+if(LLVM_ENABLE_ZLIB)
+  set(system_libs ${ZLIB_LIBRARY})
+endif()
+
 if( MSVC OR MINGW )
   # libuuid required for FOLDERID_Profile usage in lib/Support/Windows/Path.inc.
   # advapi32 required for CryptAcquireContextW in lib/Support/Windows/Path.inc.