1 #
  2 # Copyright (c) 2011, 2022, Oracle and/or its affiliates. All rights reserved.
  3 # DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  4 #
  5 # This code is free software; you can redistribute it and/or modify it
  6 # under the terms of the GNU General Public License version 2 only, as
  7 # published by the Free Software Foundation.  Oracle designates this
  8 # particular file as subject to the "Classpath" exception as provided
  9 # by Oracle in the LICENSE file that accompanied this code.
 10 #
 11 # This code is distributed in the hope that it will be useful, but WITHOUT
 12 # ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 13 # FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 14 # version 2 for more details (a copy is included in the LICENSE file that
 15 # accompanied this code).
 16 #
 17 # You should have received a copy of the GNU General Public License version
 18 # 2 along with this work; if not, write to the Free Software Foundation,
 19 # Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 20 #
 21 # Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 22 # or visit www.oracle.com if you need additional information or have any
 23 # questions.
 24 #
 25 
 26 ###############################################################################
 27 # Terminology used in this file:
 28 #
 29 # Valid features      == All possible features that the JVM knows about.
 30 # Deprecated features == Previously known features (not considered valid).
 31 # Available features  == Features that are possible to use in this configuration.
 32 # Default features    == Features that are on by default in this configuration.
 33 # Enabled features    == Features requested by the user to be present.
 34 # Disabled features   == Features excluded from being used by the user.
 35 # Active features     == The exact set of features to be used for a JVM variant.
 36 #
 37 # All valid features are considered available, unless listed as unavailable.
 38 # All available features will be turned on as default, unless listed in a filter.
 39 ###############################################################################
 40 
 41 # We need these as m4 defines to be able to loop over them using m4 later on.
 42 
 43 # All valid JVM features, regardless of platform
 44 m4_define(jvm_features_valid, m4_normalize( \
 45     ifdef([custom_jvm_features_valid], custom_jvm_features_valid) \
 46     \
 47     cds compiler1 compiler2 dtrace epsilongc g1gc jfr jni-check \
 48     jvmci jvmti link-time-opt management minimal opt-size parallelgc \
 49     serialgc services shenandoahgc static-build vm-structs zero zgc \
 50 ))
 51 
 52 # Deprecated JVM features (these are ignored, but with a warning)
 53 m4_define(jvm_features_deprecated, m4_normalize(
 54     cmsgc trace \
 55 ))
 56 
 57 # Feature descriptions
 58 m4_define(jvm_feature_desc_cds, [enable class data sharing (CDS)])
 59 m4_define(jvm_feature_desc_compiler1, [enable hotspot compiler C1])
 60 m4_define(jvm_feature_desc_compiler2, [enable hotspot compiler C2])
 61 m4_define(jvm_feature_desc_dtrace, [enable dtrace support])
 62 m4_define(jvm_feature_desc_epsilongc, [include the epsilon (no-op) garbage collector])
 63 m4_define(jvm_feature_desc_g1gc, [include the G1 garbage collector])
 64 m4_define(jvm_feature_desc_jfr, [enable JDK Flight Recorder (JFR)])
 65 m4_define(jvm_feature_desc_jni_check, [enable -Xcheck:jni support])
 66 m4_define(jvm_feature_desc_jvmci, [enable JVM Compiler Interface (JVMCI)])
 67 m4_define(jvm_feature_desc_jvmti, [enable Java Virtual Machine Tool Interface (JVM TI)])
 68 m4_define(jvm_feature_desc_link_time_opt, [enable link time optimization])
 69 m4_define(jvm_feature_desc_management, [enable java.lang.management API support])
 70 m4_define(jvm_feature_desc_minimal, [support building variant 'minimal'])
 71 m4_define(jvm_feature_desc_opt_size, [optimize the JVM library for size])
 72 m4_define(jvm_feature_desc_parallelgc, [include the parallel garbage collector])
 73 m4_define(jvm_feature_desc_serialgc, [include the serial garbage collector])
 74 m4_define(jvm_feature_desc_services, [enable diagnostic services and client attaching])
 75 m4_define(jvm_feature_desc_shenandoahgc, [include the Shenandoah garbage collector])
 76 m4_define(jvm_feature_desc_static_build, [build static library instead of dynamic])
 77 m4_define(jvm_feature_desc_vm_structs, [export JVM structures to the Serviceablility Agent])
 78 m4_define(jvm_feature_desc_zero, [support building variant 'zero'])
 79 m4_define(jvm_feature_desc_zgc, [include the Z garbage collector])
 80 
 81 ###############################################################################
 82 # Parse command line options for JVM feature selection. After this function
 83 # has run $JVM_FEATURES_ENABLED, $JVM_FEATURES_DISABLED and $JVM_FEATURES_VALID
 84 # can be used.
 85 #
 86 AC_DEFUN_ONCE([JVM_FEATURES_PARSE_OPTIONS],
 87 [
 88   # Setup shell variables from the m4 lists
 89   UTIL_SORT_LIST(JVM_FEATURES_VALID, "jvm_features_valid")
 90   UTIL_SORT_LIST(JVM_FEATURES_DEPRECATED, "jvm_features_deprecated")
 91 
 92   # For historical reasons, some jvm features have their own, shorter names.
 93   # Keep those as aliases for the --enable-jvm-feature-* style arguments.
 94   UTIL_ALIASED_ARG_ENABLE(cds, --enable-jvm-feature-cds)
 95   UTIL_ALIASED_ARG_ENABLE(dtrace, --enable-jvm-feature-dtrace)
 96 
 97   # First check for features using the
 98   # --with-jvm-features="<[-]feature>[,<[-]feature> ...]" syntax.
 99   AC_ARG_WITH([jvm-features], [AS_HELP_STRING([--with-jvm-features],
100       [JVM features to enable (foo) or disable (-foo), separated by comma. Use
101       '--help' to show possible values @<:@none@:>@])])
102   if test "x$with_jvm_features" != x; then
103     # Replace ","  with " ".
104     user_jvm_feature_list=${with_jvm_features//,/ }
105     JVM_FEATURES_ENABLED=`$ECHO $user_jvm_feature_list | \
106         $AWK '{ for (i=1; i<=NF; i++) if (!match($i, /^-.*/)) printf("%s ", $i) }'`
107     JVM_FEATURES_DISABLED=`$ECHO $user_jvm_feature_list | \
108         $AWK '{ for (i=1; i<=NF; i++) if (match($i, /^-.*/)) printf("%s ", substr($i, 2))}'`
109 
110     # Verify that the user has provided only valid (or deprecated) features
111     UTIL_GET_NON_MATCHING_VALUES(invalid_features, $JVM_FEATURES_ENABLED \
112         $JVM_FEATURES_DISABLED, $JVM_FEATURES_VALID $JVM_FEATURES_DEPRECATED)
113     if test "x$invalid_features" != x; then
114       AC_MSG_NOTICE([Unknown JVM features specified: '$invalid_features'])
115       AC_MSG_NOTICE([The available JVM features are: '$JVM_FEATURES_VALID'])
116       AC_MSG_ERROR([Cannot continue])
117     fi
118 
119     # Check if the user has provided deprecated features
120     UTIL_GET_MATCHING_VALUES(deprecated_features, $JVM_FEATURES_ENABLED \
121         $JVM_FEATURES_DISABLED, $JVM_FEATURES_DEPRECATED)
122     if test "x$deprecated_features" != x; then
123       AC_MSG_WARN([Deprecated JVM features specified (will be ignored): '$deprecated_features'])
124       # Filter out deprecated features
125       UTIL_GET_NON_MATCHING_VALUES(JVM_FEATURES_ENABLED, \
126           $JVM_FEATURES_ENABLED, $deprecated_features)
127       UTIL_GET_NON_MATCHING_VALUES(JVM_FEATURES_DISABLED, \
128           $JVM_FEATURES_DISABLED, $deprecated_features)
129     fi
130   fi
131 
132   # Then check for features using the "--enable-jvm-feature-<feature>" syntax.
133   # Using m4, loop over all features with the variable FEATURE.
134   m4_foreach(FEATURE, m4_split(jvm_features_valid), [
135     # Create an m4 variable containing a shell variable name (like
136     # "enable_jvm_feature_static_build"), and the description.
137     m4_define(FEATURE_SHELL, [enable_jvm_feature_]m4_translit(FEATURE, -, _))
138     m4_define(FEATURE_DESCRIPTION, [jvm_feature_desc_]m4_translit(FEATURE, -, _))
139 
140     AC_ARG_ENABLE(jvm-feature-FEATURE, AS_HELP_STRING(
141         [--enable-jvm-feature-FEATURE], [enable jvm feature 'FEATURE' (FEATURE_DESCRIPTION)]))
142 
143     if test "x$FEATURE_SHELL" = xyes; then
144       JVM_FEATURES_ENABLED="$JVM_FEATURES_ENABLED FEATURE"
145     elif test "x$FEATURE_SHELL" = xno; then
146       JVM_FEATURES_DISABLED="$JVM_FEATURES_DISABLED FEATURE"
147     elif test "x$FEATURE_SHELL" != x; then
148       AC_MSG_ERROR([Invalid value for --enable-jvm-feature-FEATURE: '$FEATURE_SHELL'])
149     fi
150 
151     m4_undefine([FEATURE_SHELL])
152     m4_undefine([FEATURE_DESCRIPTION])
153   ])
154 
155   # Likewise, check for deprecated arguments.
156   m4_foreach(FEATURE, m4_split(jvm_features_deprecated), [
157     AC_ARG_ENABLE(jvm-feature-FEATURE, AS_HELP_STRING(
158         [--enable-jvm-feature-FEATURE],
159         [Deprecated. Option is kept for backwards compatibility and is ignored]))
160 
161     m4_define(FEATURE_SHELL, [enable_jvm_feature_]m4_translit(FEATURE, -, _))
162 
163     if test "x$FEATURE_SHELL" != x; then
164       AC_MSG_WARN([Deprecated JVM feature, will be ignored: --enable-jvm-feature-FEATURE])
165     fi
166 
167     m4_undefine([FEATURE_SHELL])
168   ])
169 
170   # Check if the user has both enabled and disabled a feature
171   UTIL_GET_MATCHING_VALUES(enabled_and_disabled, $JVM_FEATURES_ENABLED, \
172       $JVM_FEATURES_DISABLED)
173   if test "x$enabled_and_disabled" != x; then
174     AC_MSG_NOTICE([These feature are both enabled and disabled: '$enabled_and_disabled'])
175     AC_MSG_NOTICE([This can happen if you mix --with-jvm-features and --enable-jvm-feature-*])
176     AC_MSG_NOTICE([The recommendation is to only use --enable-jvm-feature-*])
177     AC_MSG_ERROR([Cannot continue])
178   fi
179 
180   # Clean up lists and announce results to user
181   UTIL_SORT_LIST(JVM_FEATURES_ENABLED, $JVM_FEATURES_ENABLED)
182   AC_MSG_CHECKING([for JVM features enabled by the user])
183   if test "x$JVM_FEATURES_ENABLED" != x; then
184     AC_MSG_RESULT(['$JVM_FEATURES_ENABLED'])
185   else
186     AC_MSG_RESULT([none])
187   fi
188 
189   UTIL_SORT_LIST(JVM_FEATURES_DISABLED, $JVM_FEATURES_DISABLED)
190   AC_MSG_CHECKING([for JVM features disabled by the user])
191   if test "x$JVM_FEATURES_DISABLED" != x; then
192     AC_MSG_RESULT(['$JVM_FEATURES_DISABLED'])
193   else
194     AC_MSG_RESULT([none])
195   fi
196 
197   # Makefiles use VALID_JVM_FEATURES in check-jvm-feature to verify correctness.
198   VALID_JVM_FEATURES="$JVM_FEATURES_VALID"
199   AC_SUBST(VALID_JVM_FEATURES)
200 ])
201 
202 ###############################################################################
203 # Helper function for the JVM_FEATURES_CHECK_* suite.
204 # The code in the code block should assign 'false' to the variable AVAILABLE
205 # if the feature is not available, and this function will handle everything
206 # else that is needed.
207 #
208 # arg 1: The name of the feature to test
209 # arg 2: The code block to execute
210 #
211 AC_DEFUN([JVM_FEATURES_CHECK_AVAILABILITY],
212 [
213   # Assume that feature is available
214   AVAILABLE=true
215 
216   # Execute feature test block
217   $2
218 
219   AC_MSG_CHECKING([if JVM feature '$1' is available])
220   if test "x$AVAILABLE" = "xtrue"; then
221     AC_MSG_RESULT([yes])
222   else
223     AC_MSG_RESULT([no])
224     JVM_FEATURES_PLATFORM_UNAVAILABLE="$JVM_FEATURES_PLATFORM_UNAVAILABLE $1"
225   fi
226 ])
227 
228 ###############################################################################
229 # Check if the feature 'cds' is available on this platform.
230 #
231 AC_DEFUN_ONCE([JVM_FEATURES_CHECK_CDS],
232 [
233   JVM_FEATURES_CHECK_AVAILABILITY(cds, [
234     AC_MSG_CHECKING([if platform is supported by CDS])
235     if test "x$OPENJDK_TARGET_OS" = xaix; then
236       AC_MSG_RESULT([no, $OPENJDK_TARGET_OS-$OPENJDK_TARGET_CPU])
237       AVAILABLE=false
238     else
239       AC_MSG_RESULT([yes])
240     fi
241   ])
242 ])
243 
244 ###############################################################################
245 # Check if the feature 'dtrace' is available on this platform.
246 #
247 AC_DEFUN_ONCE([JVM_FEATURES_CHECK_DTRACE],
248 [
249   JVM_FEATURES_CHECK_AVAILABILITY(dtrace, [
250     AC_MSG_CHECKING([for dtrace tool])
251     if test "x$DTRACE" != "x" && test -x "$DTRACE"; then
252       AC_MSG_RESULT([$DTRACE])
253     else
254       AC_MSG_RESULT([no])
255       AVAILABLE=false
256     fi
257 
258     AC_CHECK_HEADERS([sys/sdt.h], [dtrace_headers_ok=true])
259     if test "x$dtrace_headers_ok" != "xtrue"; then
260       HELP_MSG_MISSING_DEPENDENCY([dtrace])
261       AC_MSG_NOTICE([Cannot enable dtrace with missing dependencies. See above.])
262       AVAILABLE=false
263     fi
264   ])
265 ])
266 
267 ###############################################################################
268 # Check if the feature 'jvmci' is available on this platform.
269 #
270 AC_DEFUN_ONCE([JVM_FEATURES_CHECK_JVMCI],
271 [
272   JVM_FEATURES_CHECK_AVAILABILITY(jvmci, [
273     AC_MSG_CHECKING([if platform is supported by JVMCI])
274     if test "x$OPENJDK_TARGET_CPU" = "xx86_64"; then
275       AC_MSG_RESULT([yes])
276     elif test "x$OPENJDK_TARGET_CPU" = "xaarch64"; then
277       AC_MSG_RESULT([yes])
278     else
279       AC_MSG_RESULT([no, $OPENJDK_TARGET_CPU])
280       AVAILABLE=false
281     fi
282   ])
283 ])
284 
285 ###############################################################################
286 # Check if the feature 'shenandoahgc' is available on this platform.
287 #
288 AC_DEFUN_ONCE([JVM_FEATURES_CHECK_SHENANDOAHGC],
289 [
290   JVM_FEATURES_CHECK_AVAILABILITY(shenandoahgc, [
291     AC_MSG_CHECKING([if platform is supported by Shenandoah])
292     if test "x$OPENJDK_TARGET_CPU_ARCH" = "xx86" || \
293         test "x$OPENJDK_TARGET_CPU" = "xaarch64" || \
294         test "x$OPENJDK_TARGET_CPU" = "xppc64le"; then
295       AC_MSG_RESULT([yes])
296     else
297       AC_MSG_RESULT([no, $OPENJDK_TARGET_CPU])
298       AVAILABLE=false
299     fi
300   ])
301 ])
302 
303 ###############################################################################
304 # Check if the feature 'static-build' is available on this platform.
305 #
306 AC_DEFUN_ONCE([JVM_FEATURES_CHECK_STATIC_BUILD],
307 [
308   JVM_FEATURES_CHECK_AVAILABILITY(static-build, [
309     AC_MSG_CHECKING([if static-build is enabled in configure])
310     if test "x$STATIC_BUILD" = "xtrue"; then
311       AC_MSG_RESULT([yes])
312     else
313       AC_MSG_RESULT([no, use --enable-static-build to enable static build.])
314       AVAILABLE=false
315     fi
316   ])
317 ])
318 
319 ###############################################################################
320 # Check if the feature 'zgc' is available on this platform.
321 #
322 AC_DEFUN_ONCE([JVM_FEATURES_CHECK_ZGC],
323 [
324   JVM_FEATURES_CHECK_AVAILABILITY(zgc, [
325     AC_MSG_CHECKING([if platform is supported by ZGC])
326     if test "x$OPENJDK_TARGET_CPU" = "xx86_64"; then
327       if test "x$OPENJDK_TARGET_OS" = "xlinux" || \
328           test "x$OPENJDK_TARGET_OS" = "xwindows" || \
329           test "x$OPENJDK_TARGET_OS" = "xmacosx"; then
330         AC_MSG_RESULT([yes])
331       else
332         AC_MSG_RESULT([no, $OPENJDK_TARGET_OS-$OPENJDK_TARGET_CPU])
333         AVAILABLE=false
334       fi
335     elif test "x$OPENJDK_TARGET_CPU" = "xaarch64"; then
336       if test "x$OPENJDK_TARGET_OS" = "xlinux" || \
337           test "x$OPENJDK_TARGET_OS" = "xwindows" || \
338           test "x$OPENJDK_TARGET_OS" = "xmacosx"; then
339         AC_MSG_RESULT([yes])
340       else
341         AC_MSG_RESULT([no, $OPENJDK_TARGET_OS-$OPENJDK_TARGET_CPU])
342         AVAILABLE=false
343       fi
344     elif test "x$OPENJDK_TARGET_CPU" = "xppc64le"; then
345       if test "x$OPENJDK_TARGET_OS" = "xlinux"; then
346         AC_MSG_RESULT([yes])
347       else
348         AC_MSG_RESULT([no, $OPENJDK_TARGET_OS-$OPENJDK_TARGET_CPU])
349         AVAILABLE=false
350       fi
351     else
352       AC_MSG_RESULT([no, $OPENJDK_TARGET_OS-$OPENJDK_TARGET_CPU])
353       AVAILABLE=false
354     fi
355 
356     if test "x$OPENJDK_TARGET_OS" = "xwindows"; then
357       AC_MSG_CHECKING([if Windows APIs required for ZGC is present])
358       AC_COMPILE_IFELSE(
359         [AC_LANG_PROGRAM([[#include <windows.h>]],
360           [[struct MEM_EXTENDED_PARAMETER x;]])
361         ],
362         [
363           AC_MSG_RESULT([yes])
364         ],
365         [
366           AC_MSG_RESULT([no, missing required APIs])
367           AVAILABLE=false
368         ]
369       )
370     fi
371   ])
372 ])
373 
374 ###############################################################################
375 # Setup JVM_FEATURES_PLATFORM_UNAVAILABLE and JVM_FEATURES_PLATFORM_FILTER
376 # to contain those features that are unavailable, or should be off by default,
377 # for this platform, regardless of JVM variant.
378 #
379 AC_DEFUN_ONCE([JVM_FEATURES_PREPARE_PLATFORM],
380 [
381   # The checks below should add unavailable features to
382   # JVM_FEATURES_PLATFORM_UNAVAILABLE.
383 
384   JVM_FEATURES_CHECK_CDS
385   JVM_FEATURES_CHECK_DTRACE
386   JVM_FEATURES_CHECK_JVMCI
387   JVM_FEATURES_CHECK_SHENANDOAHGC
388   JVM_FEATURES_CHECK_STATIC_BUILD
389   JVM_FEATURES_CHECK_ZGC
390 
391 ])
392 
393 ###############################################################################
394 # Setup JVM_FEATURES_VARIANT_UNAVAILABLE and JVM_FEATURES_VARIANT_FILTER
395 # to contain those features that are unavailable, or should be off by default,
396 # for this particular JVM variant.
397 #
398 # arg 1: JVM variant
399 #
400 AC_DEFUN([JVM_FEATURES_PREPARE_VARIANT],
401 [
402   variant=$1
403 
404   # Check which features are unavailable for this JVM variant.
405   # This means that is not possible to build these features for this variant.
406   if test "x$variant" = "xminimal"; then
407     JVM_FEATURES_VARIANT_UNAVAILABLE="cds zero"
408   elif test "x$variant" = "xcore"; then
409     JVM_FEATURES_VARIANT_UNAVAILABLE="cds minimal zero"
410   elif test "x$variant" = "xzero"; then
411     JVM_FEATURES_VARIANT_UNAVAILABLE="cds compiler1 compiler2 \
412         jvmci minimal zgc"
413   else
414     JVM_FEATURES_VARIANT_UNAVAILABLE="minimal zero"
415   fi
416 
417   # Check which features should be off by default for this JVM variant.
418   if test "x$variant" = "xclient"; then
419     JVM_FEATURES_VARIANT_FILTER="compiler2 jvmci link-time-opt opt-size"
420   elif test "x$variant" = "xminimal"; then
421     JVM_FEATURES_VARIANT_FILTER="cds compiler2 dtrace epsilongc g1gc \
422         jfr jni-check jvmci jvmti management parallelgc services \
423         shenandoahgc vm-structs zgc"
424     if test "x$OPENJDK_TARGET_CPU" = xarm ; then
425       JVM_FEATURES_VARIANT_FILTER="$JVM_FEATURES_VARIANT_FILTER opt-size"
426     else
427       # Only arm-32 should have link-time-opt enabled as default.
428       JVM_FEATURES_VARIANT_FILTER="$JVM_FEATURES_VARIANT_FILTER \
429           link-time-opt"
430     fi
431   elif test "x$variant" = "xcore"; then
432     JVM_FEATURES_VARIANT_FILTER="compiler1 compiler2 jvmci \
433         link-time-opt opt-size"
434   elif test "x$variant" = "xzero"; then
435     JVM_FEATURES_VARIANT_FILTER="jfr link-time-opt opt-size"
436   else
437     JVM_FEATURES_VARIANT_FILTER="link-time-opt opt-size"
438   fi
439 ])
440 
441 ###############################################################################
442 # Calculate the actual set of active JVM features for this JVM variant. Store
443 # the result in JVM_FEATURES_ACTIVE.
444 #
445 # arg 1: JVM variant
446 #
447 AC_DEFUN([JVM_FEATURES_CALCULATE_ACTIVE],
448 [
449   variant=$1
450 
451   # The default is set to all valid features except those unavailable or listed
452   # in a filter.
453   if test "x$variant" != xcustom; then
454     UTIL_GET_NON_MATCHING_VALUES(default_for_variant, $JVM_FEATURES_VALID, \
455         $JVM_FEATURES_PLATFORM_UNAVAILABLE $JVM_FEATURES_VARIANT_UNAVAILABLE \
456         $JVM_FEATURES_PLATFORM_FILTER $JVM_FEATURES_VARIANT_FILTER)
457   else
458     # Except for the 'custom' variant, where the default is to start with an
459     # empty set.
460     default_for_variant=""
461   fi
462 
463   # Verify that explicitly enabled features are available
464   UTIL_GET_MATCHING_VALUES(enabled_but_unavailable, $JVM_FEATURES_ENABLED, \
465       $JVM_FEATURES_PLATFORM_UNAVAILABLE $JVM_FEATURES_VARIANT_UNAVAILABLE)
466   if test "x$enabled_but_unavailable" != x; then
467     AC_MSG_NOTICE([ERROR: Unavailable JVM features explicitly enabled for '$variant': '$enabled_but_unavailable'])
468     AC_MSG_ERROR([Cannot continue])
469   fi
470 
471   # Notify the user if their command line options has no real effect
472   UTIL_GET_MATCHING_VALUES(enabled_but_default, $JVM_FEATURES_ENABLED, \
473       $default_for_variant)
474   if test "x$enabled_but_default" != x; then
475     AC_MSG_NOTICE([Default JVM features explicitly enabled for '$variant': '$enabled_but_default'])
476   fi
477   UTIL_GET_MATCHING_VALUES(disabled_but_unavailable, $JVM_FEATURES_DISABLED, \
478       $JVM_FEATURES_PLATFORM_UNAVAILABLE $JVM_FEATURES_VARIANT_UNAVAILABLE)
479   if test "x$disabled_but_unavailable" != x; then
480     AC_MSG_NOTICE([Unavailable JVM features explicitly disabled for '$variant': '$disabled_but_unavailable'])
481   fi
482 
483   # JVM_FEATURES_ACTIVE is the set of all default features and all explicitly
484   # enabled features, with the explicitly disabled features filtered out.
485   UTIL_GET_NON_MATCHING_VALUES(JVM_FEATURES_ACTIVE, $default_for_variant \
486       $JVM_FEATURES_ENABLED, $JVM_FEATURES_DISABLED)
487 ])
488 
489 ###############################################################################
490 # Helper function for JVM_FEATURES_VERIFY. Check if the specified JVM
491 # feature is active. To be used in shell if constructs, like this:
492 # 'if JVM_FEATURES_IS_ACTIVE(jvmti); then'
493 #
494 # Definition kept in one line to allow inlining in if statements.
495 # Additional [] needed to keep m4 from mangling shell constructs.
496 AC_DEFUN([JVM_FEATURES_IS_ACTIVE],
497 [ [ [[ " $JVM_FEATURES_ACTIVE " =~ ' '$1' ' ]] ] ])
498 
499 ###############################################################################
500 # Verify that the resulting set of features is consistent and legal.
501 #
502 # arg 1: JVM variant
503 #
504 AC_DEFUN([JVM_FEATURES_VERIFY],
505 [
506   variant=$1
507 
508   if JVM_FEATURES_IS_ACTIVE(jvmci) && ! (JVM_FEATURES_IS_ACTIVE(compiler1) || \
509       JVM_FEATURES_IS_ACTIVE(compiler2)); then
510     AC_MSG_ERROR([Specified JVM feature 'jvmci' requires feature 'compiler2' or 'compiler1' for variant '$variant'])
511   fi
512 
513   if JVM_FEATURES_IS_ACTIVE(jvmti) && ! JVM_FEATURES_IS_ACTIVE(services); then
514     AC_MSG_ERROR([Specified JVM feature 'jvmti' requires feature 'services' for variant '$variant'])
515   fi
516 
517   # For backwards compatibility, disable a feature "globally" if one variant
518   # is missing the feature.
519   if ! JVM_FEATURES_IS_ACTIVE(cds); then
520     ENABLE_CDS="false"
521   fi
522   if ! JVM_FEATURES_IS_ACTIVE(jvmci); then
523     INCLUDE_JVMCI="false"
524   fi
525   if JVM_FEATURES_IS_ACTIVE(compiler2); then
526     INCLUDE_COMPILER2="true"
527   fi
528 
529   # Verify that we have at least one gc selected (i.e., feature named "*gc").
530   if ! JVM_FEATURES_IS_ACTIVE(.*gc); then
531       AC_MSG_NOTICE([At least one gc needed for variant '$variant'.])
532       AC_MSG_NOTICE([Specified features: '$JVM_FEATURES_ACTIVE'])
533       AC_MSG_ERROR([Cannot continue])
534   fi
535 ])
536 
537 ###############################################################################
538 # Set up all JVM features for each enabled JVM variant. Requires that
539 # JVM_FEATURES_PARSE_OPTIONS has been called.
540 #
541 AC_DEFUN_ONCE([JVM_FEATURES_SETUP],
542 [
543   # Set up variant-independent factors
544   JVM_FEATURES_PREPARE_PLATFORM
545 
546   # For backwards compatibility, tentatively enable these features "globally",
547   # and disable them in JVM_FEATURES_VERIFY if a variant is found that are
548   # missing any of them.
549   ENABLE_CDS="true"
550   INCLUDE_JVMCI="true"
551   INCLUDE_COMPILER2="false"
552 
553   for variant in $JVM_VARIANTS; do
554     # Figure out if any features are unavailable, or should be filtered out
555     # by default, for this variant.
556     # Store the result in JVM_FEATURES_VARIANT_UNAVAILABLE and
557     # JVM_FEATURES_VARIANT_FILTER.
558     JVM_FEATURES_PREPARE_VARIANT($variant)
559 
560     # Calculate the resulting set of enabled features for this variant.
561     # The result is stored in JVM_FEATURES_ACTIVE.
562     JVM_FEATURES_CALCULATE_ACTIVE($variant)
563 
564     # Verify consistency for JVM_FEATURES_ACTIVE.
565     JVM_FEATURES_VERIFY($variant)
566 
567     # Keep feature list sorted and free of duplicates
568     UTIL_SORT_LIST(JVM_FEATURES_ACTIVE, $JVM_FEATURES_ACTIVE)
569     AC_MSG_CHECKING([JVM features to use for variant '$variant'])
570     AC_MSG_RESULT(['$JVM_FEATURES_ACTIVE'])
571 
572     # Save this as e.g. JVM_FEATURES_server, using indirect variable
573     # referencing.
574     features_var_name=JVM_FEATURES_$variant
575     eval $features_var_name=\"$JVM_FEATURES_ACTIVE\"
576   done
577 
578   # Unfortunately AC_SUBST does not work with non-literally named variables,
579   # so list all variants here.
580   AC_SUBST(JVM_FEATURES_server)
581   AC_SUBST(JVM_FEATURES_client)
582   AC_SUBST(JVM_FEATURES_minimal)
583   AC_SUBST(JVM_FEATURES_core)
584   AC_SUBST(JVM_FEATURES_zero)
585   AC_SUBST(JVM_FEATURES_custom)
586 
587   AC_SUBST(INCLUDE_JVMCI)
588   AC_SUBST(INCLUDE_COMPILER2)
589 
590 ])