RFR: 8257679: Improved unix compatibility layer in Windows build (winenv) [v2]

[Erik Joelsson]

On Thu, 3 Dec 2020 15:30:15 GMT, Magnus Ihse Bursie <ihse at openjdk.org> wrote:

>> For the build to work on Windows, we need a unix compatibility layer (known as the "winenv" in the build system). This can be e.g. Cygwin or Msys. The build system then needs to adapt various aspect to get the build to work in this winenv. Over time, our current solutions (which were never that well-designed) has collapsed into an unmaintainable mess.
>> 
>> This rewrite takes on a fresh approach, by giving up on the native "fixpath.exe" converter, and instead relying on a platform-independent shell script "fixpath.sh", which can dynamically adapt to the current winenv. It also provides a proper framework on how to categorize, and support, different winenvs. As a result, we now easily support Cygwin, Msys2, WSL1 and WSL2 (the latter is unfortunately not mature enough to be able to compile the JDK).
>> 
>> Furthermore, this rewrite removes all the kludges and hacks that were put in place all over the code base, and consolidates all tricky part of handling the winenv to basically two places: setting up in configure, and run-time handling by fixpath.sh.
>> 
>> This patch also cleans up our handling of how we detect tools in configure, and makes a proper framework for cross-compilation on Windows.
>
> Magnus Ihse Bursie has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Missed my last bugfix for fixpath.sh...

Overall this is very nice. Some comments and questions inline.

make/CreateJmods.gmk line 172:

> 170:   endif
> 171: else # not java.base
> 172:   ifeq ($(call isTargetOs, windows)+$(CREATING_BUILDJDK), true+false)

This looks strange. Why would CREATING_BUILDJDK be relevant here?

make/TestImage.gmk line 34:

> 32: 
> 33: ifeq ($(call isTargetOs, windows), true)
> 34:   FIXPATH_COPY := $(TEST_IMAGE_DIR)/bin/fixpath.sh

If fixpath.sh is now a static shell script in make/scripts, there is no need to transport it through the test image, is there?

make/autoconf/toolchain.m4 line 838:

> 836:     else
> 837:       if test "x$TOOLCHAIN_TYPE" = xmicrosoft; then
> 838:         # If we got no  devkit, we need to go hunting for the proper env

Double space

make/autoconf/util_paths.m4 line 401:

> 399:             if test "x$4" != xNOFIXPATH; then
> 400:               [ if [[ $FIXPATH != "" && $result =~ ^"$FIXPATH " ]]; then ]
> 401:                 result="\$FIXPATH ${result#"$FIXPATH "}"

Maybe I'm missing something, but is this unconditionally adding fixpath to any executable based just on if FIXPATH is set? Shouldn't there be a conditional on if the executable is Windows or Unix type?

make/autoconf/util_paths.m4 line 482:

> 480: ###############################################################################
> 481: # Add FIXPATH prefix to variable. Normally this is done by UTIL_LOOKUP_PROGS
> 482: # or UTIL_FIXUP_EXECUTABLE, but in some circumstances this have to be done

this _has_ to be done

make/common/JavaCompilation.gmk line 232:

> 230:       $1_JAVAC_PORT_FILE := $$(call FixPath, $$(JAVAC_SERVER_DIR)/server.port)
> 231: 
> 232:       # The servercmd specified how to launch the server. This will be executed

specifies

make/common/JavaCompilation.gmk line 241:

> 239: 
> 240:       $$($1_JAVAC_SERVER_CONFIG): $$($1_CONFIG_VARDEPS_FILE)
> 241: 	$(ECHO) portfile=$$($1_JAVAC_PORT_FILE) > $$@

Did you consider using WriteFile here?

make/modules/java.base/Copy.gmk line 48:

> 46: ################################################################################
> 47: # Copy the microsoft runtime libraries on windows
> 48: ifeq ($(call isTargetOs, windows)+$(CREATING_BUILDJDK), true+false)

Is the problem here that we don't have build versions of the runtime libraries so we simply trust that they are present on the build host instead?

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PR: https://git.openjdk.java.net/jdk/pull/1597