Re-commit "[cmake] Enable zlib support on windows"

This recommits r319533 which was broken llvm-config --system-libs
output.  The reason was that I used find_libraries for searching for the
z library.  This returns absolute paths, and when these paths made it
into llvm-config, it made it produce nonsensical flags.  To fix this, I
hand-roll a search for the library in the same way that we search for
the terminfo library a couple of lines below.

This is a bit less flexible than the find_library option, as it does not
allow the user to specify the path to the library at configure time
(which is important on windows, as zlib is unlikely to be found in any
of the standard places cmake searches), but I was able to guide the
build to find it with appropriate values of LIB and INCLUDE environment
variables.

Reviewers: compnerd, rnk, beanz, rafael

Subscribers: llvm-commits, mgorny

Differential Revision: https://reviews.llvm.org/D40779

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@319751 91177308-0d34-0410-b5e6-96231b3b80d8

cmake/config-ix.cmake

@@ -127,45 +127,55 @@ if(HAVE_LIBPTHREAD)
   set(LLVM_PTHREAD_LIB ${CMAKE_THREAD_LIBS_INIT})
 endif()
 
-# Don't look for these libraries on Windows. Also don't look for them if we're
-# using MSan, since uninstrumented third party code may call MSan interceptors
-# like strlen, leading to false positives.
-if( NOT PURE_WINDOWS AND NOT LLVM_USE_SANITIZER MATCHES "Memory.*")
-  if (LLVM_ENABLE_ZLIB)
-    check_library_exists(z compress2 "" HAVE_LIBZ)
-  else()
-    set(HAVE_LIBZ 0)
-  endif()
-  # Skip libedit if using ASan as it contains memory leaks.
-  if (LLVM_ENABLE_LIBEDIT AND HAVE_HISTEDIT_H AND NOT LLVM_USE_SANITIZER MATCHES ".*Address.*")
-    check_library_exists(edit el_init "" HAVE_LIBEDIT)
-  else()
-    set(HAVE_LIBEDIT 0)
-  endif()
-  if(LLVM_ENABLE_TERMINFO)
-    set(HAVE_TERMINFO 0)
-    foreach(library tinfo terminfo curses ncurses ncursesw)
+# 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.*")
+  set(HAVE_LIBZ 0)
+  if(LLVM_ENABLE_ZLIB)
+    foreach(library z zlib_static zlib)
       string(TOUPPER ${library} library_suffix)
-      check_library_exists(${library} setupterm "" HAVE_TERMINFO_${library_suffix})
-      if(HAVE_TERMINFO_${library_suffix})
-        set(HAVE_TERMINFO 1)
-        set(TERMINFO_LIBS "${library}")
+      check_library_exists(${library} compress2 "" HAVE_LIBZ_${library_suffix})
+      if(HAVE_LIBZ_${library_suffix})
+        set(HAVE_LIBZ 1)
+        set(ZLIB_LIBRARIES "${library}")
         break()
       endif()
     endforeach()
-  else()
-    set(HAVE_TERMINFO 0)
   endif()
 
-  find_library(ICONV_LIBRARY_PATH NAMES iconv libiconv libiconv-2 c)
-  set(LLVM_LIBXML2_ENABLED 0)
-  set(LIBXML2_FOUND 0)
-  if((LLVM_ENABLE_LIBXML2) AND ((CMAKE_SYSTEM_NAME MATCHES "Linux") AND (ICONV_LIBRARY_PATH) OR APPLE))
-    find_package(LibXml2)
-    if (LIBXML2_FOUND)
-      set(LLVM_LIBXML2_ENABLED 1)
-      include_directories(${LIBXML2_INCLUDE_DIR})
-      set(LIBXML2_LIBS "xml2")
+  # Don't look for these libraries on Windows.
+  if (NOT PURE_WINDOWS)
+    # Skip libedit if using ASan as it contains memory leaks.
+    if (LLVM_ENABLE_LIBEDIT AND HAVE_HISTEDIT_H AND NOT LLVM_USE_SANITIZER MATCHES ".*Address.*")
+      check_library_exists(edit el_init "" HAVE_LIBEDIT)
+    else()
+      set(HAVE_LIBEDIT 0)
+    endif()
+    if(LLVM_ENABLE_TERMINFO)
+      set(HAVE_TERMINFO 0)
+      foreach(library tinfo terminfo curses ncurses ncursesw)
+        string(TOUPPER ${library} library_suffix)
+        check_library_exists(${library} setupterm "" HAVE_TERMINFO_${library_suffix})
+        if(HAVE_TERMINFO_${library_suffix})
+          set(HAVE_TERMINFO 1)
+          set(TERMINFO_LIBS "${library}")
+          break()
+        endif()
+      endforeach()
+    else()
+      set(HAVE_TERMINFO 0)
+    endif()
+
+    find_library(ICONV_LIBRARY_PATH NAMES iconv libiconv libiconv-2 c)
+    set(LLVM_LIBXML2_ENABLED 0)
+    set(LIBXML2_FOUND 0)
+    if((LLVM_ENABLE_LIBXML2) AND ((CMAKE_SYSTEM_NAME MATCHES "Linux") AND (ICONV_LIBRARY_PATH) OR APPLE))
+      find_package(LibXml2)
+      if (LIBXML2_FOUND)
+        set(LLVM_LIBXML2_ENABLED 1)
+        include_directories(${LIBXML2_INCLUDE_DIR})
+        set(LIBXML2_LIBS "xml2")
+      endif()
     endif()
   endif()
 endif()

lib/Support/CMakeLists.txt

@@ -1,4 +1,7 @@
 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.
   set(system_libs ${system_libs} psapi shell32 ole32 uuid)
@@ -21,9 +24,6 @@ elseif( CMAKE_HOST_UNIX )
     set(system_libs ${system_libs} atomic)
   endif()
   set(system_libs ${system_libs} ${LLVM_PTHREAD_LIB})
-  if ( LLVM_ENABLE_ZLIB AND HAVE_LIBZ )
-    set(system_libs ${system_libs} z)
-  endif()
   if( UNIX AND NOT (BEOS OR HAIKU) )
     set(system_libs ${system_libs} m)
   endif()