Hi Andrew,
Sorry for my belated reply.
Yes, it's also an option… however, this solution seems to be
overcomplicated to export one function or two. The calling convention of
exported functions for JVM cannot be changed, they can be called from
third-party software.
If the function is used internally-only, its calling convention can be
changed as long as all components are updated.
Thank you for the pointer to another approach used to handle name
decorations of __stdcall functions. It looks we have to work out a
common approach to this problem.
Regards,
Alexey
On 27/11/2018 18:49, Andrew Luo wrote:
By the way, in hotspot we are generating a .def file dynamically while keeping
the JNICALL calling convention (for symbols such as JNI_CreateJavaVM) I believe
(just by looking through the code in
http://hg.openjdk.java.net/jdk/jdk/file/44fe5fab538a/make/hotspot/lib/JvmMapfile.gmk,
unless this code is inactive - someone who knows this area better than me
might want to comment...). Shouldn't the same approach be taken here as well?
Thanks
Andrew
-----Original Message-----
From: core-libs-dev <core-libs-dev-boun...@openjdk.java.net> On Behalf Of Ali
Ince
Sent: Monday, November 19, 2018 2:08 PM
To: Alexey Ivanov <alexey.iva...@oracle.com>; build-dev <build-dev@openjdk.java.net>;
core-libs <core-libs-...@openjdk.java.net>
Subject: Re: [PATCH] Windows 32-bit DLL name decoration
Hi Alexey,
I don’t have an account on JBS as I’m not an author yet, my OCA has just been
processed. Would it be possible for someone with an author status to create an
issue?
Regards,
Ali
On 19 Nov 2018, at 12:12, Alexey Ivanov <alexey.iva...@oracle.com> wrote:
Hi Ali,
The fix looks good to me provided it resolves your problem.
I am not a reviewer so you'll have to get OK from reviewers, likely from
build-dev and from core-libs.
Have you submitted the issue in JBS?
You have to sign OCA to be able to contribute to OpenJDK:
https://openjdk.java.net/contribute/
and also
https://openjdk.java.net/sponsor/
Regards,
Alexey
On 18/11/2018 12:07, Ali İnce wrote:
Hi Alexey,
Below is a new patch content that removes JNICALL modifiers from the exported
functions of interest. This results in exported functions not to be name
decorated and use __cdecl calling convention.
Do you have any more suggestions, or would you please guide me on next steps?
Thanks,
Ali
# HG changeset patch
# User Ali Ince <ali.i...@gmail.com>
# Date 1542542415 0
# Sun Nov 18 12:00:15 2018 +0000
# Node ID a41df44e13e1b761f4b3f05a17ed18953067ae39
# Parent 16d5ec7dbbb49ef3f969e34be870e3f917ea89ff
Remove JNICALL modifiers to prevent name decoration on 32-bit windows
builds
diff -r 16d5ec7dbbb4 -r a41df44e13e1
src/jdk.jdi/share/native/libdt_shmem/shmemBack.c
--- a/src/jdk.jdi/share/native/libdt_shmem/shmemBack.c Tue Aug 14 14:28:23
2018 +0200
+++ b/src/jdk.jdi/share/native/libdt_shmem/shmemBack.c Sun Nov 18 12:00:15
2018 +0000
@@ -339,7 +339,7 @@
return JDWPTRANSPORT_ERROR_NONE; } -JNIEXPORT jint JNICALL
+JNIEXPORT jint
jdwpTransport_OnLoad(JavaVM *vm, jdwpTransportCallback* cbTablePtr,
jint version, jdwpTransportEnv** result) {
diff -r 16d5ec7dbbb4 -r a41df44e13e1
src/jdk.jdwp.agent/share/native/include/jdwpTransport.h
--- a/src/jdk.jdwp.agent/share/native/include/jdwpTransport.h Tue Aug 14
14:28:23 2018 +0200
+++ b/src/jdk.jdwp.agent/share/native/include/jdwpTransport.h Sun Nov 18
12:00:15 2018 +0000
@@ -140,7 +140,7 @@
void (*free)(void *buffer); /* Call this for all deallocations */
} jdwpTransportCallback;
-typedef jint (JNICALL *jdwpTransport_OnLoad_t)(JavaVM *jvm,
+typedef jint (*jdwpTransport_OnLoad_t)(JavaVM *jvm,
jdwpTransportCallback
*callback,
jint version,
jdwpTransportEnv**
env); diff -r 16d5ec7dbbb4 -r a41df44e13e1
src/jdk.jdwp.agent/share/native/libdt_socket/socketTransport.c
--- a/src/jdk.jdwp.agent/share/native/libdt_socket/socketTransport.c Tue Aug
14 14:28:23 2018 +0200
+++ b/src/jdk.jdwp.agent/share/native/libdt_socket/socketTransport.c Sun Nov
18 12:00:15 2018 +0000
@@ -1019,7 +1019,7 @@
return JDWPTRANSPORT_ERROR_NONE; } -JNIEXPORT jint JNICALL
+JNIEXPORT jint
jdwpTransport_OnLoad(JavaVM *vm, jdwpTransportCallback* cbTablePtr,
jint version, jdwpTransportEnv** env) {
On 16 Nov 2018, at 23:03, Alexey Ivanov <alexey.iva...@oracle.com> wrote:
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.h
tml
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, \
