[CMake] Simplify CMake handling for zlib

Rather than handling zlib handling manually, use find_package from CMake
to find zlib properly. Use this to normalize the LLVM_ENABLE_ZLIB,
HAVE_ZLIB, HAVE_ZLIB_H. Furthermore, require zlib if LLVM_ENABLE_ZLIB is
set to YES, which requires the distributor to explicitly select whether
zlib is enabled or not. This simplifies the CMake handling and usage in
the rest of the tooling.

This is a reland of abb0075 with all followup changes and fixes that
should address issues that were reported in PR44780.

Differential Revision: https://reviews.llvm.org/D79219

cmake/config-ix.cmake

@@ -56,7 +56,6 @@ check_include_file(sys/types.h HAVE_SYS_TYPES_H)
 check_include_file(termios.h HAVE_TERMIOS_H)
 check_include_file(unistd.h HAVE_UNISTD_H)
 check_include_file(valgrind/valgrind.h HAVE_VALGRIND_VALGRIND_H)
-check_include_file(zlib.h HAVE_ZLIB_H)
 check_include_file(fenv.h HAVE_FENV_H)
 check_symbol_exists(FE_ALL_EXCEPT "fenv.h" HAVE_DECL_FE_ALL_EXCEPT)
 check_symbol_exists(FE_INEXACT "fenv.h" HAVE_DECL_FE_INEXACT)
@@ -118,17 +117,13 @@ 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.*")
-  set(HAVE_LIBZ 0)
   if(LLVM_ENABLE_ZLIB)
-    foreach(library z zlib_static zlib)
-      string(TOUPPER ${library} library_suffix)
-      check_library_exists(${library} compress2 "" HAVE_LIBZ_${library_suffix})
-      if(HAVE_LIBZ_${library_suffix})
-        set(HAVE_LIBZ 1)
-        set(ZLIB_LIBRARIES "${library}")
-        break()
-      endif()
-    endforeach()
+    if(LLVM_ENABLE_ZLIB STREQUAL FORCE_ON)
+      find_package(ZLIB REQUIRED)
+    else()
+      find_package(ZLIB)
+    endif()
+    set(LLVM_ENABLE_ZLIB "${ZLIB_FOUND}")
   endif()
 
   # Don't look for these libraries on Windows.
@@ -169,16 +164,14 @@ if(NOT LLVM_USE_SANITIZER MATCHES "Memory.*")
       endif()
     endif()
   endif()
+else()
+  set(LLVM_ENABLE_ZLIB FALSE)
 endif()
 
 if (LLVM_ENABLE_LIBXML2 STREQUAL "FORCE_ON" AND NOT LLVM_LIBXML2_ENABLED)
   message(FATAL_ERROR "Failed to congifure libxml2")
 endif()
 
-if (LLVM_ENABLE_ZLIB STREQUAL "FORCE_ON" AND NOT HAVE_LIBZ)
-  message(FATAL_ERROR "Failed to configure zlib")
-endif()
-
 check_library_exists(xar xar_open "" HAVE_LIBXAR)
 if(HAVE_LIBXAR)
   set(XAR_LIB xar)
@@ -517,13 +510,6 @@ else( LLVM_ENABLE_THREADS )
   message(STATUS "Threads disabled.")
 endif()
 
-if (LLVM_ENABLE_ZLIB )
-  # Check if zlib is available in the system.
-  if ( NOT HAVE_ZLIB_H OR NOT HAVE_LIBZ )
-    set(LLVM_ENABLE_ZLIB 0)
-  endif()
-endif()
-
 if (LLVM_ENABLE_DOXYGEN)
   message(STATUS "Doxygen enabled.")
   find_package(Doxygen REQUIRED)

cmake/modules/LLVMConfig.cmake.in

@@ -51,6 +51,9 @@ set(LLVM_ENABLE_THREADS @LLVM_ENABLE_THREADS@)
 set(LLVM_ENABLE_UNWIND_TABLES @LLVM_ENABLE_UNWIND_TABLES@)
 
 set(LLVM_ENABLE_ZLIB @LLVM_ENABLE_ZLIB@)
+if(LLVM_ENABLE_ZLIB)
+  find_package(ZLIB)
+endif()
 
 set(LLVM_LIBXML2_ENABLED @LLVM_LIBXML2_ENABLED@)
 

include/llvm/Config/config.h.cmake

@@ -115,9 +115,6 @@
 /* Define to 1 if you have the `pthread_setname_np' function. */
 #cmakedefine HAVE_PTHREAD_SETNAME_NP ${HAVE_PTHREAD_SETNAME_NP}
 
-/* Define to 1 if you have the `z' library (-lz). */
-#cmakedefine HAVE_LIBZ ${HAVE_LIBZ}
-
 /* Define to 1 if you have the <link.h> header file. */
 #cmakedefine HAVE_LINK_H ${HAVE_LINK_H}
 
@@ -226,9 +223,6 @@
 /* Define to 1 if you have the <valgrind/valgrind.h> header file. */
 #cmakedefine HAVE_VALGRIND_VALGRIND_H ${HAVE_VALGRIND_VALGRIND_H}
 
-/* Define to 1 if you have the <zlib.h> header file. */
-#cmakedefine HAVE_ZLIB_H ${HAVE_ZLIB_H}
-
 /* Have host's _alloca */
 #cmakedefine HAVE__ALLOCA ${HAVE__ALLOCA}
 

lib/Support/CMakeLists.txt

@@ -1,7 +1,7 @@
-set(system_libs)
-if ( LLVM_ENABLE_ZLIB AND HAVE_LIBZ )
-  set(system_libs ${system_libs} ${ZLIB_LIBRARIES})
+if(LLVM_ENABLE_ZLIB)
+  set(imported_libs ZLIB::ZLIB)
 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.
@@ -194,10 +194,35 @@ add_llvm_component_library(LLVMSupport
   ${LLVM_MAIN_INCLUDE_DIR}/llvm/ADT
   ${LLVM_MAIN_INCLUDE_DIR}/llvm/Support
   ${Backtrace_INCLUDE_DIRS}
-  LINK_LIBS ${system_libs} ${delayload_flags} ${Z3_LINK_FILES}
+  LINK_LIBS ${system_libs} ${imported_libs} ${delayload_flags} ${Z3_LINK_FILES}
   )
 
-set_property(TARGET LLVMSupport PROPERTY LLVM_SYSTEM_LIBS "${system_libs}")
+set(llvm_system_libs ${system_libs})
+
+if(LLVM_ENABLE_ZLIB)
+  # CMAKE_BUILD_TYPE is only meaningful to single-configuration generators.
+  if(CMAKE_BUILD_TYPE)
+    string(TOUPPER ${CMAKE_BUILD_TYPE} build_type)
+    get_property(zlib_library TARGET ZLIB::ZLIB PROPERTY LOCATION_${build_type})
+  endif()
+  if(NOT zlib_library)
+    get_property(zlib_library TARGET ZLIB::ZLIB PROPERTY LOCATION)
+  endif()
+  get_filename_component(zlib_library ${zlib_library} NAME)
+  if(CMAKE_STATIC_LIBRARY_PREFIX AND CMAKE_STATIC_LIBRARY_SUFFIX AND
+      zlib_library MATCHES "^${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 ${zlib_library})
+  endif()
+  if(CMAKE_SHARED_LIBRARY_PREFIX AND CMAKE_SHARED_LIBRARY_SUFFIX AND
+      zlib_library MATCHES "^${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}")
 
 if(LLVM_WITH_Z3)
   target_include_directories(LLVMSupport SYSTEM

lib/Support/CRC.cpp

@@ -25,7 +25,7 @@
 
 using namespace llvm;
 
-#if LLVM_ENABLE_ZLIB == 0 || !HAVE_ZLIB_H
+#if !LLVM_ENABLE_ZLIB
 
 static const uint32_t CRCTable[256] = {
     0x00000000, 0x77073096, 0xee0e612c, 0x990951ba, 0x076dc419, 0x706af48f,

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 == 1 && HAVE_ZLIB_H
+#if LLVM_ENABLE_ZLIB
 #include <zlib.h>
 #endif
 
 using namespace llvm;
 
-#if LLVM_ENABLE_ZLIB == 1 && HAVE_LIBZ
+#if LLVM_ENABLE_ZLIB
 static Error createError(StringRef Err) {
   return make_error<StringError>(Err, inconvertibleErrorCode());
 }

test/CMakeLists.txt

@@ -1,12 +1,12 @@
 llvm_canonicalize_cmake_booleans(
   BUILD_SHARED_LIBS
   HAVE_LIBXAR
-  HAVE_LIBZ
   HAVE_OCAMLOPT
   HAVE_OCAML_OUNIT
   LLVM_ENABLE_DIA_SDK
   LLVM_ENABLE_FFI
   LLVM_ENABLE_THREADS
+  LLVM_ENABLE_ZLIB
   LLVM_INCLUDE_GO_TESTS
   LLVM_LIBXML2_ENABLED
   LLVM_LINK_LLVM_DYLIB

test/lit.site.cfg.py.in

@@ -33,7 +33,7 @@ config.host_cxx = "@HOST_CXX@"
 config.host_ldflags = '@HOST_LDFLAGS@'
 config.llvm_use_intel_jitevents = @LLVM_USE_INTEL_JITEVENTS@
 config.llvm_use_sanitizer = "@LLVM_USE_SANITIZER@"
-config.have_zlib = @HAVE_LIBZ@
+config.have_zlib = @LLVM_ENABLE_ZLIB@
 config.have_libxar = @HAVE_LIBXAR@
 config.have_dia_sdk = @LLVM_ENABLE_DIA_SDK@
 config.enable_ffi = @LLVM_ENABLE_FFI@

unittests/Support/CompressionTest.cpp

@@ -21,7 +21,7 @@ using namespace llvm;
 
 namespace {
 
-#if LLVM_ENABLE_ZLIB == 1 && HAVE_LIBZ
+#if LLVM_ENABLE_ZLIB
 
 void TestZlibCompression(StringRef Input, int Level) {
   SmallString<32> Compressed;

utils/gn/secondary/clang/test/BUILD.gn

@@ -79,9 +79,9 @@ write_lit_config("lit_site_cfg") {
   }
 
   if (llvm_enable_zlib) {
-    extra_values += [ "HAVE_LIBZ=1" ]
+    extra_values += [ "LLVM_ENABLE_ZLIB=1" ]
   } else {
-    extra_values += [ "HAVE_LIBZ=0" ]  # Must be 0.
+    extra_values += [ "LLVM_ENABLE_ZLIB=0" ]  # Must be 0.
   }
 
   if (host_cpu == "x64") {

utils/gn/secondary/compiler-rt/test/BUILD.gn

@@ -86,8 +86,8 @@ write_cmake_config("lit_common_configured") {
   }
 
   if (llvm_enable_zlib) {
-    values += [ "HAVE_LIBZ=1" ]
+    values += [ "LLVM_ENABLE_ZLIB=1" ]
   } else {
-    values += [ "HAVE_LIBZ=0" ]
+    values += [ "LLVM_ENABLE_ZLIB=0" ]
   }
 }

utils/gn/secondary/lld/test/BUILD.gn

@@ -49,9 +49,9 @@ write_lit_cfg("lit_site_cfg") {
   }
 
   if (llvm_enable_zlib) {
-    extra_values += [ "HAVE_LIBZ=1" ]
+    extra_values += [ "LLVM_ENABLE_ZLIB=1" ]
   } else {
-    extra_values += [ "HAVE_LIBZ=0" ]  # Must be 0.
+    extra_values += [ "LLVM_ENABLE_ZLIB=0" ]  # Must be 0.
   }
 
   if (current_cpu == "x64" || current_cpu == "arm64" ||

utils/gn/secondary/llvm/include/llvm/Config/BUILD.gn

@@ -295,20 +295,10 @@ write_cmake_config("config") {
     values += [ "LLVM_ENABLE_DIA_SDK=" ]
   }
 
-  # FIXME: Once https://reviews.llvm.org/D79219 is in, remove the two
-  # redundant HAVE_ variables.
   if (llvm_enable_zlib) {
-    values += [
-      "HAVE_LIBZ=1",
-      "HAVE_ZLIB_H=1",
-      "LLVM_ENABLE_ZLIB=1",
-    ]
+    values += [ "LLVM_ENABLE_ZLIB=1" ]
   } else {
-    values += [
-      "HAVE_LIBZ=",
-      "HAVE_ZLIB_H=",
-      "LLVM_ENABLE_ZLIB=",
-    ]
+    values += [ "LLVM_ENABLE_ZLIB=" ]
   }
 
   if (llvm_enable_libxml2) {

utils/gn/secondary/llvm/test/BUILD.gn

@@ -174,9 +174,9 @@ write_lit_config("lit_site_cfg") {
   }
 
   if (llvm_enable_zlib) {
-    extra_values += [ "HAVE_LIBZ=1" ]
+    extra_values += [ "LLVM_ENABLE_ZLIB=1" ]
   } else {
-    extra_values += [ "HAVE_LIBZ=0" ]  # Must be 0.
+    extra_values += [ "LLVM_ENABLE_ZLIB=0" ]  # Must be 0.
   }
 }