Fix gRPC linking on ELF ABI.

Signed-off-by: WenTao Ou <[email protected]>

cmake/opentelemetry-proto.cmake

@@ -232,6 +232,10 @@ include_directories("${GENERATED_PROTOBUF_PATH}")
 unset(OTELCPP_PROTO_TARGET_OPTIONS)
 if(CMAKE_SYSTEM_NAME MATCHES "Windows|MinGW|WindowsStore")
   list(APPEND OTELCPP_PROTO_TARGET_OPTIONS STATIC)
+elseif(NOT DEFINED BUILD_SHARED_LIBS OR BUILD_SHARED_LIBS)
+  list(APPEND OTELCPP_PROTO_TARGET_OPTIONS SHARED)
+else()
+  list(APPEND OTELCPP_PROTO_TARGET_OPTIONS STATIC)
 endif()
 
 list(
@@ -285,10 +289,9 @@ if(WITH_OTLP_GRPC)
   if(WITH_ABSEIL)
     find_package(absl CONFIG)
     if(TARGET absl::synchronization)
-      target_link_libraries(opentelemetry_proto INTERFACE absl::synchronization)
+      target_link_libraries(opentelemetry_proto PRIVATE absl::synchronization)
     endif()
   endif()
-  target_link_libraries(opentelemetry_proto PUBLIC gRPC::grpc++)
 endif()
 
 if(BUILD_SHARED_LIBS)

exporters/otlp/CMakeLists.txt

@@ -15,28 +15,31 @@ target_include_directories(
          "$<INSTALL_INTERFACE:include>")
 
 set(OPENTELEMETRY_OTLP_TARGETS opentelemetry_otlp_recordable)
-target_link_libraries(
-  opentelemetry_otlp_recordable
-  PUBLIC opentelemetry_trace opentelemetry_resources opentelemetry_proto)
 
 if(WITH_LOGS_PREVIEW)
   target_link_libraries(opentelemetry_otlp_recordable PUBLIC opentelemetry_logs)
 endif()
 target_link_libraries(opentelemetry_otlp_recordable
                       PUBLIC opentelemetry_metrics)
 
+set(OPENTELEMETRY_PROTO_LINK_NAME opentelemetry_proto)
 if(WITH_OTLP_GRPC)
+  # Because opentelemetry_proto may depend on gRPC, and gRPC can only be linked
+  # in one dynamic library or executable (otherwise, there may be conflicts with
+  # some global variables in certain versions of gRPC), we have switched the
+  # link for opentelemetry_exporter_otlp_grpc_client into all targets that
+  # depend on opentelemetry_proto.
+  set(OPENTELEMETRY_PROTO_LINK_NAME opentelemetry_exporter_otlp_grpc_client)
   find_package(gRPC REQUIRED)
   add_library(opentelemetry_exporter_otlp_grpc_client src/otlp_grpc_client.cc
                                                       src/otlp_grpc_utils.cc)
   set_target_properties(opentelemetry_exporter_otlp_grpc_client
                         PROPERTIES EXPORT_NAME otlp_grpc_client)
   target_link_libraries(
     opentelemetry_exporter_otlp_grpc_client
-    PUBLIC opentelemetry_sdk opentelemetry_ext opentelemetry_proto)
-
-  target_link_libraries(opentelemetry_exporter_otlp_grpc_client
-                        PRIVATE gRPC::grpc++)
+    PUBLIC opentelemetry_sdk opentelemetry_ext
+           # gRPC::grpc++ must be linked before opentelemetry_proto.
+           opentelemetry_proto gRPC::grpc++)
   get_target_property(GRPC_INCLUDE_DIRECTORY gRPC::grpc++
                       INTERFACE_INCLUDE_DIRECTORIES)
   if(GRPC_INCLUDE_DIRECTORY)
@@ -102,8 +105,8 @@ if(WITH_OTLP_HTTP)
                         PROPERTIES EXPORT_NAME otlp_http_client)
   target_link_libraries(
     opentelemetry_exporter_otlp_http_client
-    PUBLIC opentelemetry_sdk opentelemetry_proto opentelemetry_http_client_curl
-           nlohmann_json::nlohmann_json)
+    PUBLIC opentelemetry_sdk ${OPENTELEMETRY_PROTO_LINK_NAME}
+           opentelemetry_http_client_curl nlohmann_json::nlohmann_json)
   if(nlohmann_json_clone)
     add_dependencies(opentelemetry_exporter_otlp_http_client
                      nlohmann_json::nlohmann_json)
@@ -162,6 +165,11 @@ if(WITH_OTLP_HTTP)
        opentelemetry_exporter_otlp_http_metric)
 endif()
 
+target_link_libraries(
+  opentelemetry_otlp_recordable
+  PUBLIC opentelemetry_trace opentelemetry_resources
+         ${OPENTELEMETRY_PROTO_LINK_NAME})
+
 if(OPENTELEMETRY_INSTALL)
   install(
     TARGETS ${OPENTELEMETRY_OTLP_TARGETS}