Revert abb00753 "build: reduce CMake handling for zlib" (PR44780)

and follow-ups:
a2ca1c2d "build: disable zlib by default on Windows"
2181bf40 "[CMake] Link against ZLIB::ZLIB"
1079c68a "Attempt to fix ZLIB CMake logic on Windows"

This changed the output of llvm-config --system-libs, and more
importantly it broke stand-alone builds. Instead of piling on more fix
attempts, let's revert this to reduce the risk of more breakages.

(cherry picked from commit 916be8fd6a0a0feea4cefcbeb0c22c65848d7a2e)

3 files changed, 8 insertions, 29 deletions

diff --git a/llvm/lib/Support/CMakeLists.txt b/llvm/lib/Support/CMakeLists.txt
index 5c656164e77..ddc4d2324a0 100644
--- a/llvm/lib/Support/CMakeLists.txt
+++ b/llvm/lib/Support/CMakeLists.txt
@@ -1,7 +1,7 @@
-if(LLVM_ENABLE_ZLIB)
-  set(imported_libs ZLIB::ZLIB)
+set(system_libs)
+if ( LLVM_ENABLE_ZLIB AND HAVE_LIBZ )
+  set(system_libs ${system_libs} ${ZLIB_LIBRARIES})
 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.
@@ -186,31 +186,10 @@ add_llvm_component_library(LLVMSupport
   ${LLVM_MAIN_INCLUDE_DIR}/llvm/ADT
   ${LLVM_MAIN_INCLUDE_DIR}/llvm/Support
   ${Backtrace_INCLUDE_DIRS}
-  LINK_LIBS ${system_libs} ${imported_libs} ${delayload_flags} ${Z3_LINK_FILES}
+  LINK_LIBS ${system_libs} ${delayload_flags} ${Z3_LINK_FILES}
   )
 
-set(llvm_system_libs ${system_libs})
-
-if(LLVM_ENABLE_ZLIB)
-  string(TOUPPER ${CMAKE_BUILD_TYPE} build_type)
-  get_property(zlib_library TARGET ZLIB::ZLIB PROPERTY LOCATION_${build_type})
-  if(NOT zlib_library)
-    get_property(zlib_library TARGET ZLIB::ZLIB PROPERTY LOCATION)
-  endif()
-  get_filename_component(zlib_library ${zlib_library} NAME)
-  if(CMAKE_STATIC_LIBRARY_PREFIX AND
-     zlib_library MATCHES "^${CMAKE_STATIC_LIBRARY_PREFIX}.*${CMAKE_STATIC_LIBRARY_SUFFIX}$")
-    STRING(REGEX REPLACE "^${CMAKE_STATIC_LIBRARY_PREFIX}" "" zlib_library ${zlib_library})
-    STRING(REGEX REPLACE "${CMAKE_STATIC_LIBRARY_SUFFIX}$" "" zlib_library ${zlib_library})
-  elseif(CMAKE_SHARED_LIBRARY_PREFIX AND
-         zlib_library MATCHES "^${CMAKE_SHARED_LIBRARY_PREFIX}.*${CMAKE_SHARED_LIBRARY_SUFFIX}$")
-    STRING(REGEX REPLACE "^${CMAKE_SHARED_LIBRARY_PREFIX}" "" zlib_library ${zlib_library})
-    STRING(REGEX REPLACE "${CMAKE_SHARED_LIBRARY_SUFFIX}$" "" zlib_library ${zlib_library})
-  endif()
-  set(llvm_system_libs ${llvm_system_libs} "${zlib_library}")
-endif()
-
-set_property(TARGET LLVMSupport PROPERTY LLVM_SYSTEM_LIBS "${llvm_system_libs}")
+set_property(TARGET LLVMSupport PROPERTY LLVM_SYSTEM_LIBS "${system_libs}")
 
 if(LLVM_WITH_Z3)
   target_include_directories(LLVMSupport SYSTEM
diff --git a/llvm/lib/Support/CRC.cpp b/llvm/lib/Support/CRC.cpp
index 2bc668beed3..7ff09debe3b 100644
--- a/llvm/lib/Support/CRC.cpp
+++ b/llvm/lib/Support/CRC.cpp
@@ -25,7 +25,7 @@
 
 using namespace llvm;
 
-#if !LLVM_ENABLE_ZLIB
+#if LLVM_ENABLE_ZLIB == 0 || !HAVE_ZLIB_H
 
 static const uint32_t CRCTable[256] = {
     0x00000000, 0x77073096, 0xee0e612c, 0x990951ba, 0x076dc419, 0x706af48f,
diff --git a/llvm/lib/Support/Compression.cpp b/llvm/lib/Support/Compression.cpp
index 4165a2740cd..97d5ffaadf8 100644
--- a/llvm/lib/Support/Compression.cpp
+++ b/llvm/lib/Support/Compression.cpp
@@ -17,13 +17,13 @@
 #include "llvm/Support/Compiler.h"
 #include "llvm/Support/Error.h"
 #include "llvm/Support/ErrorHandling.h"
-#if LLVM_ENABLE_ZLIB
+#if LLVM_ENABLE_ZLIB == 1 && HAVE_ZLIB_H
 #include <zlib.h>
 #endif
 
 using namespace llvm;
 
-#if LLVM_ENABLE_ZLIB
+#if LLVM_ENABLE_ZLIB == 1 && HAVE_LIBZ
 static Error createError(StringRef Err) {
   return make_error<StringError>(Err, inconvertibleErrorCode());
 }