diff --git a/CMakeLists.txt b/CMakeLists.txt
index bf8ffe91fc1..0cca8745ec6 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,4 +1,5 @@
 cmake_minimum_required(VERSION 3.4)
+include(CheckCCompilerFlag)
 
 configure_file("version.config" "version.config" COPYONLY)
 file(READ version.config VERSION_CONFIG)
@@ -19,6 +20,12 @@ else ()
   set(PROJECT_VERSION_MOD ${VERSION})
 endif ()
 
+# Set project name, version, and language. Language needs to be set for compiler checks
+project(timescaledb VERSION ${VERSION} LANGUAGES C)
+
+message(STATUS "TimescaleDB version ${PROJECT_VERSION_MOD}. Can be updated from version ${UPDATE_FROM_VERSION}")
+message(STATUS "Build type is ${CMAKE_BUILD_TYPE}")
+
 set(PROJECT_INSTALL_METHOD source CACHE STRING "Specify what install platform this binary
 is built for")
 
@@ -27,12 +34,32 @@ if (NOT CMAKE_BUILD_TYPE)
   set(CMAKE_BUILD_TYPE Release CACHE STRING "Choose the type of build, options are: None Debug Release RelWithDebInfo MinSizeRel" FORCE)
 endif ()
 
+set(SUPPORTED_COMPILERS "GNU" "Clang" "AppleClang" "MSVC")
+
+# Check for a supported compiler
+if (NOT CMAKE_C_COMPILER_ID IN_LIST SUPPORTED_COMPILERS)
+   message(FATAL_ERROR "Unsupported compiler ${CMAKE_C_COMPILER_ID}. Supported compilers are: ${SUPPORTED_COMPILERS}")
+endif ()
+
+# Check for supported platforms and compiler flags
 if (WIN32)
   if (NOT CMAKE_CONFIGURATION_TYPES)
     # Default to only include Release builds so MSBuild.exe 'just works'
     set(CMAKE_CONFIGURATION_TYPES Release CACHE STRING "Semicolon separated list of supported configuration types, only supports Debug, Release, MinSizeRel, and RelWithDebInfo, anything else will be ignored." FORCE)
   endif ()
-endif (WIN32)
+elseif (UNIX)
+  # On UNIX, the compiler needs to support -fvisibility=hidden to hide symbols by default
+  check_c_compiler_flag(-fvisibility=hidden CC_SUPPORTS_VISIBILITY_HIDDEN)
+
+  if (NOT CC_SUPPORTS_VISIBILITY_HIDDEN)
+    message(FATAL_ERROR "The compiler ${CMAKE_C_COMPILER_ID} does not support -fvisibility=hidden")
+  endif (NOT CC_SUPPORTS_VISIBILITY_HIDDEN)
+else ()
+  message(FATAL_ERROR "Unsupported platform")
+endif ()
+
+message(STATUS "Using compiler ${CMAKE_C_COMPILER_ID}")
+
 if (ENABLE_CODECOVERAGE)
   message(STATUS "Running code coverage")
 
@@ -57,11 +84,6 @@ if (ENABLE_CODECOVERAGE)
 
 endif (ENABLE_CODECOVERAGE)
 
-project(timescaledb VERSION ${VERSION} LANGUAGES C)
-
-message(STATUS "TimescaleDB version ${PROJECT_VERSION_MOD}. Can be updated from version ${UPDATE_FROM_VERSION}")
-message(STATUS "Build type is ${CMAKE_BUILD_TYPE}")
-
 # Search paths for Postgres binaries
 if (WIN32)
   find_path(PG_PATH
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 8199b9db1b6..4d4e06858e8 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -3,7 +3,7 @@ set(CMAKE_C_FLAGS_DEBUG "-DUSE_ASSERT_CHECKING=1")
 if (UNIX)
   set(CMAKE_SHARED_LINKER_FLAGS "${CMAKE_SHARED_LINKER_FLAGS} -L${PG_LIBDIR}")
   set(CMAKE_MODULE_LINKER_FLAGS "${CMAKE_MODULE_LINKER_FLAGS} -L${PG_LIBDIR}")
-  set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} ${PG_CFLAGS}")
+  set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} ${PG_CFLAGS} -fvisibility=hidden")
   set(CMAKE_CPP_FLAGS "${CMAKE_CPP_FLAGS} ${PG_CPPFLAGS}")
   set(CMAKE_C_FLAGS_DEBUG "${CMAKE_C_FLAGS_DEBUG} -g")
 endif (UNIX)
@@ -58,6 +58,7 @@ set(HEADERS
   errors.h
   event_trigger.h
   extension.h
+  export.h
   guc.h
   hypercube.h
   hypertable_cache.h
@@ -125,6 +126,11 @@ set(SOURCES
 configure_file(version.h.in version.h)
 set(GITCOMMIT_H ${CMAKE_CURRENT_BINARY_DIR}/gitcommit.h)
 
+# Add test source code in Debug builds
+if (CMAKE_BUILD_TYPE MATCHES Debug)
+  set(TEST_SOURCES ../test/src/symbol_conflict.c)
+endif (CMAKE_BUILD_TYPE MATCHES Debug)
+
 if (WIN32)
   add_custom_command(
     OUTPUT ${GITCOMMIT_H}
@@ -164,12 +170,18 @@ if (PGINDENT)
     DEPENDS typedefs.list)
 endif (PGINDENT)
 
-add_library(${PROJECT_NAME} MODULE ${SOURCES} ${HEADERS} ${GITCOMMIT_H})
+add_library(${PROJECT_NAME} MODULE ${SOURCES} ${TEST_SOURCES} ${HEADERS} ${GITCOMMIT_H})
 
 set_target_properties(${PROJECT_NAME} PROPERTIES
     OUTPUT_NAME ${PROJECT_NAME}-${PROJECT_VERSION_MOD}
     PREFIX "")
 
+if (CMAKE_BUILD_TYPE MATCHES Debug)
+  # This define generates extension-specific code for symbol conflict testing
+  target_compile_definitions(${PROJECT_NAME} PRIVATE MODULE_NAME=${PROJECT_NAME})
+endif (CMAKE_BUILD_TYPE MATCHES Debug)
+
+
 install(
   TARGETS ${PROJECT_NAME}
   DESTINATION ${PG_PKGLIBDIR})
diff --git a/src/compat.h b/src/compat.h
index 0c074ce21db..afa1dd98312 100644
--- a/src/compat.h
+++ b/src/compat.h
@@ -1,6 +1,8 @@
 #ifndef TIMESCALEDB_COMPAT_H
 #define TIMESCALEDB_COMPAT_H
 
+#include "export.h"
+
 #define is_supported_pg_version_96(version) ((version >= 90603) && (version < 100000))
 #define is_supported_pg_version_10(version) ((version >= 100002) && (version < 110000))
 #define is_supported_pg_version(version) (is_supported_pg_version_96(version) || is_supported_pg_version_10(version))
@@ -56,8 +58,4 @@
 
 #endif							/* PG_VERSION_NUM */
 
-#define TS_FUNCTION_INFO_V1(fn) \
-	PGDLLEXPORT Datum fn(PG_FUNCTION_ARGS); \
-	PG_FUNCTION_INFO_V1(fn)
-
 #endif							/* TIMESCALEDB_COMPAT_H */
diff --git a/src/export.h b/src/export.h
new file mode 100644
index 00000000000..dc33f6f12d2
--- /dev/null
+++ b/src/export.h
@@ -0,0 +1,35 @@
+#ifndef TIMESCALEDB_EXPORT_H
+#define TIMESCALEDB_EXPORT_H
+
+#include <postgres.h>
+
+/* Definitions for symbol exports */
+
+#define TS_CAT(x,y) x ## y
+#define TS_EMPTY(x) (TS_CAT(x, 87628) == 87628)
+
+#if defined(_WIN32) && !defined(WIN32)
+#define WIN32
+#endif
+
+#if !defined(WIN32) && !defined(__CYGWIN__)
+#if __GNUC__ >= 4
+#if defined(PGDLLEXPORT)
+#if TS_EMPTY(PGDLLEXPORT)
+/* PGDLLEXPORT is defined but empty. We can safely undef it. */
+#undef PGDLLEXPORT
+#else
+#error "PGDLLEXPORT is already defined"
+#endif
+#endif							/* defined(PGDLLEXPORT) */
+#define PGDLLEXPORT __attribute__ ((visibility ("default")))
+#else
+#error "Unsupported GNUC version"
+#endif							/* __GNUC__ */
+#endif
+
+#define TS_FUNCTION_INFO_V1(fn) \
+	PGDLLEXPORT Datum fn(PG_FUNCTION_ARGS); \
+	PG_FUNCTION_INFO_V1(fn)
+
+#endif							/* TIMESCALEDB_EXPORT_H */
diff --git a/src/init.c b/src/init.c
index 135fb9007ee..78e6a774296 100644
--- a/src/init.c
+++ b/src/init.c
@@ -9,6 +9,7 @@
 #include "guc.h"
 #include "catalog.h"
 #include "version.h"
+#include "compat.h"
 
 #ifdef PG_MODULE_MAGIC
 PG_MODULE_MAGIC;
diff --git a/src/loader/CMakeLists.txt b/src/loader/CMakeLists.txt
index 49d1267b033..4e6b802a011 100644
--- a/src/loader/CMakeLists.txt
+++ b/src/loader/CMakeLists.txt
@@ -4,7 +4,19 @@ set(HEADERS
 set(SOURCES
   loader.c)
 
-add_library(${PROJECT_NAME}-loader MODULE ${SOURCES} ${HEADERS})
+# Include code for tests in Debug build
+if (CMAKE_BUILD_TYPE MATCHES Debug)
+  set(TEST_SOURCES ../../test/src/symbol_conflict.c)
+endif (CMAKE_BUILD_TYPE MATCHES Debug)
+
+add_library(${PROJECT_NAME}-loader MODULE ${SOURCES} ${TEST_SOURCES} ${HEADERS})
+
+if (CMAKE_BUILD_TYPE MATCHES Debug)
+  add_subdirectory(../../test/loader-mock/ "${CMAKE_CURRENT_BINARY_DIR}/mock")
+
+  # This define generates extension-specific code for symbol conflict testing
+  target_compile_definitions(${PROJECT_NAME}-loader PUBLIC MODULE_NAME=loader)
+endif (CMAKE_BUILD_TYPE MATCHES Debug)
 
 set_target_properties(${PROJECT_NAME}-loader PROPERTIES
     OUTPUT_NAME ${PROJECT_NAME}
@@ -13,7 +25,3 @@ set_target_properties(${PROJECT_NAME}-loader PROPERTIES
 install(
   TARGETS ${PROJECT_NAME}-loader
   DESTINATION ${PG_PKGLIBDIR})
-
-if(CMAKE_BUILD_TYPE MATCHES Debug)
-  add_subdirectory(../../test/loader-mock/ "${CMAKE_CURRENT_BINARY_DIR}/mock")
-endif(CMAKE_BUILD_TYPE MATCHES Debug)
diff --git a/src/loader/loader.c b/src/loader/loader.c
index de8323957ca..52568ebf5ae 100644
--- a/src/loader/loader.c
+++ b/src/loader/loader.c
@@ -13,6 +13,7 @@
 #define EXTENSION_NAME "timescaledb"
 
 #include "../extension_utils.c"
+#include "../export.h"
 
 #define PG96 ((PG_VERSION_NUM >= 90600) && (PG_VERSION_NUM < 100000))
 #define PG10 ((PG_VERSION_NUM >= 100000) && (PG_VERSION_NUM < 110000))
diff --git a/test/expected/symbol_conflict.out b/test/expected/symbol_conflict.out
new file mode 100644
index 00000000000..5a6dbac5255
--- /dev/null
+++ b/test/expected/symbol_conflict.out
@@ -0,0 +1,28 @@
+\c single :ROLE_SUPERUSER
+-- Test for symbol conflicts between the loader module and the
+-- versioned extension module.
+-- This test fails on, e.g. Linux, unless compiled with -fvisibility=hidden
+CREATE OR REPLACE FUNCTION hello_loader() RETURNS TEXT
+AS 'timescaledb', 'loader_hello' LANGUAGE C IMMUTABLE PARALLEL SAFE STRICT;
+SELECT hello_loader();
+   hello_loader    
+-------------------
+ hello from loader
+(1 row)
+
+CREATE OR REPLACE FUNCTION hello_timescaledb() RETURNS TEXT
+AS :MODULE_PATHNAME, 'timescaledb_hello' LANGUAGE C IMMUTABLE PARALLEL SAFE STRICT;
+-- This calls an internal function with a conflicting name in the loader
+SELECT hello_loader();
+   hello_loader    
+-------------------
+ hello from loader
+(1 row)
+
+-- This calls the identically named internal function in the versioned extension
+SELECT hello_timescaledb();
+   hello_timescaledb    
+------------------------
+ hello from timescaledb
+(1 row)
+
diff --git a/test/loader-mock/src/CMakeLists.txt b/test/loader-mock/src/CMakeLists.txt
index 77d498e1b47..dbd98c5c3fe 100644
--- a/test/loader-mock/src/CMakeLists.txt
+++ b/test/loader-mock/src/CMakeLists.txt
@@ -1,10 +1,10 @@
 set(SOURCES
-  init.c 
-  ../../../src/extension.c
-  ../../../src/guc.c
-  )
+  init.c
+  ${PROJECT_SOURCE_DIR}/src/extension.c
+  ${PROJECT_SOURCE_DIR}/src/guc.c
+)
 
-include_directories(BEFORE ${CMAKE_CURRENT_SOURCE_DIR})
+include_directories(BEFORE ${CMAKE_CURRENT_SOURCE_DIR} ${PROJECT_SOURCE_DIR}/src)
 
 add_library(${PROJECT_NAME}-mock-1 MODULE ${SOURCES} version.h)
 add_library(${PROJECT_NAME}-mock-2 MODULE ${SOURCES} version.h)
@@ -34,5 +34,3 @@ foreach(MOCK_VERSION mock-1 mock-2 mock-3 mock-4 mock-broken mock-5 mock-6)
     TARGETS ${PROJECT_NAME}-${MOCK_VERSION}
     DESTINATION ${PG_PKGLIBDIR} OPTIONAL)
 endforeach(MOCK_VERSION)
-
-
diff --git a/test/loader-mock/src/init.c b/test/loader-mock/src/init.c
index 9b8eb266fed..ac870d4a1e7 100644
--- a/test/loader-mock/src/init.c
+++ b/test/loader-mock/src/init.c
@@ -9,13 +9,11 @@
 #include <nodes/print.h>
 #include <access/parallel.h>
 
+#include "export.h"
+
 #define STR_EXPAND(x) #x
 #define STR(x) STR_EXPAND(x)
 
-#define TS_FUNCTION_INFO_V1(fn) \
-	PGDLLEXPORT Datum fn(PG_FUNCTION_ARGS); \
-	PG_FUNCTION_INFO_V1(fn)
-
 #ifdef PG_MODULE_MAGIC
 PG_MODULE_MAGIC;
 #endif
diff --git a/test/sql/CMakeLists.txt b/test/sql/CMakeLists.txt
index 7b96fc9dd4c..e4c6a6fae41 100644
--- a/test/sql/CMakeLists.txt
+++ b/test/sql/CMakeLists.txt
@@ -59,7 +59,7 @@ set(TEST_FILES
 
 IF(CMAKE_BUILD_TYPE MATCHES Debug)
   list(APPEND TEST_FILES
-    loader.sql)
+    loader.sql symbol_conflict.sql)
 ENDIF(CMAKE_BUILD_TYPE MATCHES Debug)
 
 IF (${PG_VERSION_MAJOR} GREATER "9")
diff --git a/test/sql/symbol_conflict.sql b/test/sql/symbol_conflict.sql
new file mode 100644
index 00000000000..2ab7db1df35
--- /dev/null
+++ b/test/sql/symbol_conflict.sql
@@ -0,0 +1,17 @@
+\c single :ROLE_SUPERUSER
+
+-- Test for symbol conflicts between the loader module and the
+-- versioned extension module.
+-- This test fails on, e.g. Linux, unless compiled with -fvisibility=hidden
+CREATE OR REPLACE FUNCTION hello_loader() RETURNS TEXT
+AS 'timescaledb', 'loader_hello' LANGUAGE C IMMUTABLE PARALLEL SAFE STRICT;
+
+SELECT hello_loader();
+
+CREATE OR REPLACE FUNCTION hello_timescaledb() RETURNS TEXT
+AS :MODULE_PATHNAME, 'timescaledb_hello' LANGUAGE C IMMUTABLE PARALLEL SAFE STRICT;
+
+-- This calls an internal function with a conflicting name in the loader
+SELECT hello_loader();
+-- This calls the identically named internal function in the versioned extension
+SELECT hello_timescaledb();
diff --git a/test/src/symbol_conflict.c b/test/src/symbol_conflict.c
new file mode 100644
index 00000000000..5b56b10cfa4
--- /dev/null
+++ b/test/src/symbol_conflict.c
@@ -0,0 +1,27 @@
+#include <postgres.h>
+#include <utils/builtins.h>
+#include <fmgr.h>
+#include "../../src/compat.h"
+
+#define STR_EXPAND(x) #x
+#define STR(x) STR_EXPAND(x)
+
+#define FUNC_EXPAND(prefix, name) prefix##_##name
+#define FUNC(prefix, name) FUNC_EXPAND(prefix, name)
+
+/* Function with conflicting name when included in multiple modules */
+extern const char *test_symbol_conflict(void);
+
+const char *
+test_symbol_conflict(void)
+{
+	return "hello from " STR(MODULE_NAME);
+}
+
+TS_FUNCTION_INFO_V1(FUNC(MODULE_NAME, hello));
+
+Datum
+FUNC(MODULE_NAME, hello) (PG_FUNCTION_ARGS)
+{
+	PG_RETURN_TEXT_P(cstring_to_text(test_symbol_conflict()));
+}