[Support] [Debuginfod] Use libcurl imported library.

[noajshu]

Summary

A report on llvm-dev indicated that curl.h could be found during build configuration but not during compilation. This diff uses the libcurl imported library created by findcurl, so that includes and libs are automatically managed correctly by cmake.

[phosek]

llvm/lib/Support/CMakeLists.txt

79 ↗

(On Diff #392185)

You need to use the imported library here instead which configures both the include directory and the library. See zlib case above where we do the same.

296 ↗

(On Diff #392185)

You also need to replicate the ZLIB block above for CURL here.

318–323 ↗

(On Diff #392185)

This shouldn't be needed.

[noajshu]

Treat Curl similar to Zlib.

[noajshu]

Add block for importing curl with llvm-config.

[phosek]

LGTM

[noajshu]

Rebase against main after landing D115131.
Now I am seeing this:

CMake Warning (dev) in CMakeLists.txt:
  Policy CMP0111 is not set: An imported target missing its location property
  fails during generation.  Run "cmake --help-policy CMP0111" for policy
  details.  Use the cmake_policy command to set the policy and suppress this
  warning.

  IMPORTED_LOCATION not set for imported target "CURL::libcurl" configuration
  "Debug".
This warning is for project developers.  Use -Wno-dev to suppress it.

CMake Warning (dev) in CMakeLists.txt:
  Policy CMP0111 is not set: An imported target missing its location property
  fails during generation.  Run "cmake --help-policy CMP0111" for policy
  details.  Use the cmake_policy command to set the policy and suppress this
  warning.

  IMPORTED_LOCATION not set for imported target "CURL::libcurl" configuration
  "Debug".
This warning is for project developers.  Use -Wno-dev to suppress it.

CMake Warning (dev) in CMakeLists.txt:
  Policy CMP0111 is not set: An imported target missing its location property
  fails during generation.  Run "cmake --help-policy CMP0111" for policy
  details.  Use the cmake_policy command to set the policy and suppress this
  warning.

  IMPORTED_LOCATION not set for imported target "CURL::libcurl" configuration
  "Debug".
This warning is for project developers.  Use -Wno-dev to suppress it.

And then when I try to build, I get:

ninja: Entering directory `build'
ninja: error: 'CURL::libcurl-NOTFOUND', needed by 'unittests/Debuginfod/DebuginfodTests', missing and no known rule to make it

[phosek]

In D115189#3175224, @noajshu wrote:

ninja: Entering directory `build'
ninja: error: 'CURL::libcurl-NOTFOUND', needed by 'unittests/Debuginfod/DebuginfodTests', missing and no known rule to make it

This means that cURL wasn't found so LLVM_ENABLE_CURL should evaluate to false, but in your case it appears to be evaluating to true. I'd check https://github.com/llvm/llvm-project/blob/b206ee69061120d559d8315bede6c63758b06154/llvm/cmake/config-ix.cmake#L180.

[noajshu]

Remove extra whitespace line.

llvm/lib/Debuginfod/CMakeLists.txt

 # Link LibCURL if the user wants it
 if (LLVM_ENABLE_CURL)
-  set(imported_libs ${CURL_LIBRARIES})
+  set(imported_libs CURL::libcurl)
 endif()
 
 add_llvm_component_library(LLVMDebuginfod
   Debuginfod.cpp
   HTTPClient.cpp
 
   ADDITIONAL_HEADER_DIRS
   ${LLVM_MAIN_INCLUDE_DIR}/llvm/Debuginfod
 
   LINK_LIBS
   ${imported_libs}
 
   LINK_COMPONENTS
   Support
   )
 
-set(llvm_system_libs ${system_libs})
+# This block is only needed for llvm-config. When we deprecate llvm-config and
+# move to using CMake export, this block can be removed.
+if(LLVM_ENABLE_CURL)
+  # CMAKE_BUILD_TYPE is only meaningful to single-configuration generators.
+  if(CMAKE_BUILD_TYPE)
+    string(TOUPPER ${CMAKE_BUILD_TYPE} build_type)
+    get_property(curl_library TARGET CURL::libcurl PROPERTY LOCATION_${build_type})
+  endif()
+  if(NOT curl_library)
+    get_property(curl_library TARGET CURL::libcurl PROPERTY LOCATION)
+  endif()
+  get_library_name(${curl_library} curl_library)
+  set(llvm_system_libs ${llvm_system_libs} "${curl_library}")
+endif()