Hi Ali,
It's exactly what I referred to.
Yes, it does change the calling convention.
Yet it's not a (big) problem because both parties will use the same
calling convention.
Using a DLL from another build will not be possible. But it's not a good
idea to do so anyway.
Mapfiles and export options have been removed by
https://bugs.openjdk.java.net/browse/JDK-8200178 to simplify managing
exported functions. So that to add or remove an exported function, you
don't have modify makefiles and/or mapfiles. You just edit the source files.
Regards,
Alexey
On 16/11/2018 22:42, Ali İnce wrote:
Hi Alexey,
Thanks for your reply.
I will definitely give it a try though I’m not sure if that’ll be a breaking
change. This is because JNICALL modifier is defined to be __stdcall on windows
which is both specified on jdwpTransport_OnLoad exported functions both for
dt_socket.dll and dt_shmem.dll.
The __stdcall is ignored on x64 platforms and also name decoration is not
applied
(https://docs.microsoft.com/en-gb/cpp/build/reference/decorated-names?view=vs-2017).
I believe that’s why we don’t experience any problems on x64 builds.
Removing JNICALL (thus __stdcall) modifier (apparently only applies to x86
builds) will result in the calling convention to be changed, and thus will
change how parameters are ordered and also the stack cleanup rules. I think
this may result in problems in programs that are designed to load shared
libraries and its exported functions at runtime (not bound by link time which
probably won’t cause any issues - assuming that they use the shared function
signature) - as in
https://github.com/AdoptOpenJDK/openjdk-jdk11u/blob/5f01925b80ed851b133ee26fbcb07026ac04149e/src/jdk.jdwp.agent/share/native/libjdwp/transport.c#L99.
Any thoughts?
Regards,
Ali
On 15 Nov 2018, at 22:14, Alexey Ivanov <alexey.iva...@oracle.com> wrote:
Hi Ali,
Can the issue be resolved by using different call modifiers on the affected
functions?
Some build / link issues were resolved by adding / removing JNICALL modifier,
see
https://bugs.openjdk.java.net/browse/JDK-8201226
http://mail.openjdk.java.net/pipermail/build-dev/2018-April/021553.html
https://bugs.openjdk.java.net/browse/JDK-8202476
http://mail.openjdk.java.net/pipermail/build-dev/2018-May/021913.html
Regards,
Alexey
On 15/11/2018 21:43, Ali İnce wrote:
Hi,
An issue (https://github.com/AdoptOpenJDK/openjdk-build/issues/709) raised
against AdoptOpenJDK jdk11 32-bit windows builds led us to the name decoration
problem on built 32-bit dlls - specifically dt_socket.dll and dt_shmem.dll.
Whereas 64-bit MSVC builds don’t apply any name decorations on exported
functions, 32-bit builds apply them - which requires either def files or
/export flags to be specified on the linker arguments.
Although the expected linker arguments were present on previous jdk makefiles,
they were removed in jdk11 makefiles.
Below is the proposed patch, which can also be browsed at
https://github.com/AdoptOpenJDK/openjdk-jdk11u/pull/1.
Would you please have a look and let me know of any points I may have missed (I
don’t have any background information about why the export flags were removed
in jdk11)?
Regards,
Ali
diff --git a/make/lib/Lib-jdk.jdi.gmk b/make/lib/Lib-jdk.jdi.gmk
index 197b95c2e2..ac6ebf5591 100644
--- a/make/lib/Lib-jdk.jdi.gmk
+++ b/make/lib/Lib-jdk.jdi.gmk
@@ -37,6 +37,7 @@ ifeq ($(OPENJDK_TARGET_OS), windows)
jdk.jdwp.agent:include \
jdk.jdwp.agent:libjdwp/export, \
LDFLAGS := $(LDFLAGS_JDKLIB), \
+ LDFLAGS_windows := -export:jdwpTransport_OnLoad, \
LIBS := $(JDKLIB_LIBS), \
))
diff --git a/make/lib/Lib-jdk.jdwp.agent.gmk b/make/lib/Lib-jdk.jdwp.agent.gmk
index 0bc93e0d35..0382e55325 100644
--- a/make/lib/Lib-jdk.jdwp.agent.gmk
+++ b/make/lib/Lib-jdk.jdwp.agent.gmk
@@ -37,6 +37,7 @@ $(eval $(call SetupJdkLibrary, BUILD_LIBDT_SOCKET, \
libjdwp/export, \
LDFLAGS := $(LDFLAGS_JDKLIB) \
$(call SET_SHARED_LIBRARY_ORIGIN), \
+ LDFLAGS_windows := -export:jdwpTransport_OnLoad, \
LIBS_linux := -lpthread, \
LIBS_solaris := -lnsl -lsocket, \
LIBS_windows := $(JDKLIB_LIBS) ws2_32.lib, \
