From 697c69468e8972764a5a595e9d81bd356e9d2e42 Mon Sep 17 00:00:00 2001
From: "Uwe L. Korn" <uwe.korn@quantco.com>
Date: Fri, 21 Oct 2022 11:00:31 +0200
Subject: [PATCH 2/2] [CMake] Fix Findzstd module for shared DLL on Windows

Differential Revision: https://reviews.llvm.org/D136065
---
 llvm/cmake/modules/Findzstd.cmake | 28 ++++++++++++++++++++++++----
 1 file changed, 24 insertions(+), 4 deletions(-)

diff --git a/llvm/cmake/modules/Findzstd.cmake b/llvm/cmake/modules/Findzstd.cmake
index fab9ea803..3890bd236 100644
--- a/llvm/cmake/modules/Findzstd.cmake
+++ b/llvm/cmake/modules/Findzstd.cmake
@@ -3,6 +3,7 @@
 # If successful, the following variables will be defined:
 # zstd_INCLUDE_DIR
 # zstd_LIBRARY
+# zstd_STATIC_LIBRARY
 # zstd_FOUND
 #
 # Additionally, one of the following import targets will be defined:
@@ -19,6 +20,9 @@ endif()
 
 find_path(zstd_INCLUDE_DIR NAMES zstd.h)
 find_library(zstd_LIBRARY NAMES zstd zstd_static)
+find_library(zstd_STATIC_LIBRARY NAMES
+  zstd_static
+  "${CMAKE_STATIC_LIBRARY_PREFIX}zstd${CMAKE_STATIC_LIBRARY_SUFFIX}")
 
 include(FindPackageHandleStandardArgs)
 find_package_handle_standard_args(
@@ -30,20 +34,36 @@ if(zstd_FOUND)
   if(zstd_LIBRARY MATCHES "${zstd_SHARED_LIBRARY_SUFFIX}$" AND
      NOT TARGET zstd::libzstd_shared)
     add_library(zstd::libzstd_shared SHARED IMPORTED)
-    set_target_properties(zstd::libzstd_shared PROPERTIES
+    if(MSVC)
+      # IMPORTED_LOCATION is the path to the DLL and IMPORTED_IMPLIB is the "library".
+      get_filename_component(zstd_DIRNAME "${zstd_LIBRARY}" DIRECTORY)
+      string(REGEX REPLACE "${CMAKE_INSTALL_LIBDIR}$" "${CMAKE_INSTALL_BINDIR}" zstd_DIRNAME "${zstd_DIRNAME}")
+      get_filename_component(zstd_BASENAME "${zstd_LIBRARY}" NAME)
+      string(REGEX REPLACE "\\${CMAKE_LINK_LIBRARY_SUFFIX}$" "${CMAKE_SHARED_LIBRARY_SUFFIX}" zstd_BASENAME "${zstd_BASENAME}")
+      set_target_properties(zstd::libzstd_shared PROPERTIES
+          INTERFACE_INCLUDE_DIRECTORIES "${zstd_INCLUDE_DIR}"
+          IMPORTED_LOCATION "${zstd_DIRNAME}/${zstd_BASENAME}"
+          IMPORTED_IMPLIB "${zstd_LIBRARY}")
+      unset(zstd_DIRNAME)
+      unset(zstd_BASENAME)
+    else()
+      set_target_properties(zstd::libzstd_shared PROPERTIES
           INTERFACE_INCLUDE_DIRECTORIES "${zstd_INCLUDE_DIR}"
           IMPORTED_LOCATION "${zstd_LIBRARY}")
+    endif()
+  else()
+    set(zstd_STATIC_LIBRARY "${zstd_LIBRARY}")
   endif()
-  if(zstd_LIBRARY MATCHES "${zstd_STATIC_LIBRARY_SUFFIX}$" AND
+  if(zstd_STATIC_LIBRARY MATCHES "${zstd_STATIC_LIBRARY_SUFFIX}$" AND
      NOT TARGET zstd::libzstd_static)
     add_library(zstd::libzstd_static STATIC IMPORTED)
     set_target_properties(zstd::libzstd_static PROPERTIES
         INTERFACE_INCLUDE_DIRECTORIES "${zstd_INCLUDE_DIR}"
-        IMPORTED_LOCATION "${zstd_LIBRARY}")
+        IMPORTED_LOCATION "${zstd_STATIC_LIBRARY}")
   endif()
 endif()
 
 unset(zstd_SHARED_LIBRARY_SUFFIX)
 unset(zstd_STATIC_LIBRARY_SUFFIX)
 
-mark_as_advanced(zstd_INCLUDE_DIR zstd_LIBRARY)
+mark_as_advanced(zstd_INCLUDE_DIR zstd_LIBRARY zstd_STATIC_LIBRARY)
-- 
2.37.0 (Apple Git-136)