Reduce the default maximum heap size for all Scala processes. (#5350)

* bazel_tools: Set `unused_dependency_checker_mode` in one place.

* bazel_tools: Set the default max heap size for Scala processes to 2GB.

And the default initial max heap size to 512MB.

CHANGELOG_BEGIN
CHANGELOG_END

* bazel_tools: Set the `scalac` heap size to 2GB and stack size to 2MB.

* bazel_tools: Delete `da_scala_macro_library`, as it's unused.

* bazel_tools: Revert the description of `da_scala_library_suite`.

Misread it.

BAZEL-JVM.md

@@ -498,17 +498,6 @@ Scala source file, and bundle them in one target. This rule takes the same
 attributes as `da_scala_library` with the exception of
 `unused_dependency_checker_mode` which will always be disabled.
 
-If a Scala library defines macros then you must use the
-`da_scala_macro_library` rule instead of the above. Otherwise, you will encounter 
-compiler errors of the following form (formatted for readability):
-
-```
-error: macro annotation could not be expanded (the most common reason
-for that is that you need to enable the macro paradise plugin; another
-possibility is that you try to use macro annotation in the same
-compilation run that defines it)
-```
-
 #### Tests
 
 Scala tests can be defined using the `da_scala_test` rule. It will generate an
@@ -547,6 +536,10 @@ da_scala_test_suite(
     # Expected runtime and resource requirements.
     size = "small",
     ...
+
+    # You can adjust the heap size as follows:
+    initial_heap_size = "512m",
+    max_heap_size = "2g",
 )
 ```
 
@@ -554,6 +547,11 @@ The `size` attribute is used to determine the default timeout and resource
 requirements. Refer to the [official documentation][bazel_test_size] for
 details about test size and other common test attributes.
 
+A couple of arguments have been added:
+
+  * `initial_heap_size` is translated to `-Xms`, and defaults to `512m`, and
+  * `max_heap_size` is translated to `-Xmx`, and defaults to `2g`.
+
 #### Executables
 
 Scala executables can be defined using the `da_scala_binary` rule. It will
@@ -581,6 +579,10 @@ da_scala_binary(
     # A list of files that should be present in the runtime path at runtime.
     data = [ ... ],
     ...
+
+    # You can adjust the heap size as follows:
+    initial_heap_size = "512m",
+    max_heap_size = "2g",
 )
 ```
 

BAZEL.md

@@ -807,12 +807,6 @@ da_scala_library(
 )
 ```
 
-### Scala Macro Libraries
-
-If a Scala library defines macros that should be used by other Scala targets
-later on, then it has to be defined using `da_scala_macro_library`. Macros may
-not be defined and used within the same target.
-
 ### Scala Executables
 
 Scala executables are defined using `da_scala_binary`. It takes most of the

bazel_tools/scala.bzl

@@ -6,7 +6,6 @@ load(
     "scala_binary",
     "scala_library",
     "scala_library_suite",
-    "scala_macro_library",
     "scala_test",
     "scala_test_suite",
 )
@@ -121,6 +120,44 @@ lf_scalacopts = [
     "-Ywarn-unused",
 ]
 
+default_compile_arguments = {
+    "unused_dependency_checker_mode": "error",
+}
+
+default_initial_heap_size = "512m"
+default_max_heap_size = "2g"
+default_scalac_stack_size = "2m"
+
+def _jvm_flags(initial_heap_size, max_heap_size):
+    return ["-Xms{}".format(initial_heap_size), "-Xmx{}".format(max_heap_size)]
+
+def _set_compile_jvm_flags(
+        arguments,
+        initial_heap_size = default_initial_heap_size,
+        max_heap_size = default_max_heap_size,
+        scalac_stack_size = default_scalac_stack_size):
+    jvm_flags = _jvm_flags(initial_heap_size, max_heap_size)
+    result = {}
+    result.update(arguments)
+    result.update({
+        "scalac_jvm_flags": arguments.get("scalac_jvm_flags", []) + ["-Xss{}".format(scalac_stack_size)] + jvm_flags,
+    })
+    return result
+
+def _set_jvm_flags(
+        arguments,
+        initial_heap_size = default_initial_heap_size,
+        max_heap_size = default_max_heap_size,
+        scalac_stack_size = default_scalac_stack_size):
+    jvm_flags = _jvm_flags(initial_heap_size, max_heap_size)
+    result = {}
+    result.update(arguments)
+    result.update({
+        "scalac_jvm_flags": arguments.get("scalac_jvm_flags", []) + ["-Xss{}".format(scalac_stack_size)] + jvm_flags,
+        "jvm_flags": arguments.get("jvm_flags", []) + jvm_flags,
+    })
+    return result
+
 def _wrap_rule(rule, name = "", scalacopts = [], plugins = [], generated_srcs = [], **kwargs):
     rule(
         name = name,
@@ -408,7 +445,7 @@ def _create_scaladoc_jar(**kwargs):
             tags = ["scaladoc"],
         )
 
-def da_scala_library(name, unused_dependency_checker_mode = "error", **kwargs):
+def da_scala_library(name, **kwargs):
     """
     Define a Scala library.
 
@@ -418,13 +455,16 @@ def da_scala_library(name, unused_dependency_checker_mode = "error", **kwargs):
 
     [rules_scala_library_docs]: https://github.com/bazelbuild/rules_scala/blob/master/docs/scala_library.md
     """
-    kwargs["unused_dependency_checker_mode"] = unused_dependency_checker_mode
-    _wrap_rule(scala_library, name, **kwargs)
-    _create_scala_source_jar(name = name, **kwargs)
-    _create_scaladoc_jar(name = name, **kwargs)
+    arguments = {}
+    arguments.update(default_compile_arguments)
+    arguments.update(kwargs)
+    arguments = _set_compile_jvm_flags(arguments)
+    _wrap_rule(scala_library, name, **arguments)
+    _create_scala_source_jar(name = name, **arguments)
+    _create_scaladoc_jar(name = name, **arguments)
 
-    if "tags" in kwargs:
-        for tag in kwargs["tags"]:
+    if "tags" in arguments:
+        for tag in arguments["tags"]:
             if tag.startswith("maven_coordinates="):
                 pom_file(
                     name = name + "_pom",
@@ -442,30 +482,20 @@ def da_scala_library_suite(name, **kwargs):
 
     [rules_scala_library_suite_docs]: https://github.com/bazelbuild/rules_scala/blob/master/docs/scala_library_suite.md
     """
-    _wrap_rule(scala_library_suite, name, **kwargs)
-    _create_scala_source_jar(name = name, **kwargs)
-    _create_scaladoc_jar(name = name, **kwargs)
+    arguments = {}
+    arguments.update(kwargs)
+    arguments = _set_compile_jvm_flags(arguments)
+    _wrap_rule(scala_library_suite, name, **arguments)
+    _create_scala_source_jar(name = name, **arguments)
+    _create_scaladoc_jar(name = name, **arguments)
 
-    if "tags" in kwargs:
-        for tag in kwargs["tags"]:
+    if "tags" in arguments:
+        for tag in arguments["tags"]:
             if tag.startswith("maven_coordinates="):
                 fail("Usage of maven_coordinates in da_scala_library_suite is NOT supported", "tags")
                 break
 
-def da_scala_macro_library(**kwargs):
-    """
-    Define a Scala library that contains macros.
-
-    Applies common Scala options defined in `bazel_tools/scala.bzl`.
-    And forwards to `scala_macro_library` from `rules_scala`.
-    Refer to the [`rules_scala` documentation][rules_scala_docs].
-
-    [rules_scala_docs]: https://github.com/bazelbuild/rules_scala#scala_library
-    """
-    _wrap_rule(scala_macro_library, **kwargs)
-    _create_scala_source_jar(**kwargs)
-
-def da_scala_binary(name, unused_dependency_checker_mode = "error", **kwargs):
+def da_scala_binary(name, initial_heap_size = default_initial_heap_size, max_heap_size = default_max_heap_size, **kwargs):
     """
     Define a Scala executable.
 
@@ -475,11 +505,14 @@ def da_scala_binary(name, unused_dependency_checker_mode = "error", **kwargs):
 
     [rules_scala_docs]: https://github.com/bazelbuild/rules_scala#scala_binary
     """
-    kwargs["unused_dependency_checker_mode"] = unused_dependency_checker_mode
-    _wrap_rule(scala_binary, name, **kwargs)
+    arguments = {}
+    arguments.update(default_compile_arguments)
+    arguments.update(kwargs)
+    arguments = _set_jvm_flags(arguments, initial_heap_size = initial_heap_size, max_heap_size = max_heap_size)
+    _wrap_rule(scala_binary, name, **arguments)
 
-    if "tags" in kwargs:
-        for tag in kwargs["tags"]:
+    if "tags" in arguments:
+        for tag in arguments["tags"]:
             if tag.startswith("maven_coordinates="):
                 pom_file(
                     name = name + "_pom",
@@ -499,7 +532,7 @@ def da_scala_binary(name, unused_dependency_checker_mode = "error", **kwargs):
                 )
                 break
 
-def da_scala_test(unused_dependency_checker_mode = "error", **kwargs):
+def da_scala_test(initial_heap_size = default_initial_heap_size, max_heap_size = default_max_heap_size, **kwargs):
     """
     Define a Scala executable that runs the unit tests in the given source files.
 
@@ -509,10 +542,13 @@ def da_scala_test(unused_dependency_checker_mode = "error", **kwargs):
 
     [rules_scala_docs]: https://github.com/bazelbuild/rules_scala#scala_test
     """
-    kwargs["unused_dependency_checker_mode"] = unused_dependency_checker_mode
-    _wrap_rule(scala_test, **kwargs)
+    arguments = {}
+    arguments.update(default_compile_arguments)
+    arguments.update(kwargs)
+    arguments = _set_jvm_flags(arguments, initial_heap_size = initial_heap_size, max_heap_size = max_heap_size)
+    _wrap_rule(scala_test, **arguments)
 
-def da_scala_test_suite(**kwargs):
+def da_scala_test_suite(initial_heap_size = default_initial_heap_size, max_heap_size = default_max_heap_size, **kwargs):
     """
     Define a Scala test executable for each source file and bundle them into one target.
 
@@ -522,7 +558,10 @@ def da_scala_test_suite(**kwargs):
 
     [rules_scala_docs]: https://github.com/bazelbuild/rules_scala#scala_test_suite
     """
-    _wrap_rule(scala_test_suite, use_short_names = is_windows, **kwargs)
+    arguments = {}
+    arguments.update(kwargs)
+    arguments = _set_jvm_flags(arguments, initial_heap_size = initial_heap_size, max_heap_size = max_heap_size)
+    _wrap_rule(scala_test_suite, use_short_names = is_windows, **arguments)
 
 # TODO make the jmh rule work with plugins -- probably
 # just a matter of passing the flag in

language-support/scala/codegen-sample-app/BUILD.bazel

@@ -50,11 +50,6 @@ da_scala_library(
         # Plugins have to be specified as JARs.
         "@maven//:org_spire_math_kind_projector_2_12",
     ],
-    # Bump stack size to avoid stack overflow in reflection.
-    scalac_jvm_flags = [
-        "-Xmx2G",
-        "-Xss2M",
-    ],
     visibility = [
         "//visibility:public",
     ],

language-support/scala/codegen/BUILD.bazel

@@ -13,10 +13,6 @@ common_scalacopts = [
     "CONFIG",
 ]
 
-common_jvm_flags = [
-    "-Xmx2G",
-]
-
 da_scala_library(
     name = "codegen",
     srcs =
@@ -32,7 +28,6 @@ da_scala_library(
         # Plugins have to be specified as JARs.
         "@maven//:org_spire_math_kind_projector_2_12",
     ],
-    scalac_jvm_flags = common_jvm_flags,
     scalacopts = common_scalacopts,
     tags = ["maven_coordinates=com.daml:codegen-scala:__VERSION__"],
     visibility = [
@@ -79,7 +74,6 @@ da_scala_test_suite(
     name = "tests",
     size = "small",
     srcs = glob(["src/test/scala/**/*.scala"]),
-    jvm_flags = common_jvm_flags,
     scalacopts = common_scalacopts,
     deps = [
         ":codegen",

navigator/backend/BUILD.bazel

@@ -14,10 +14,6 @@ navigator_scalacopts = [
     "-Xsource:2.13",
 ]
 
-common_jvm_flags = [
-    "-Xmx2G",
-]
-
 # All frontend resource files.
 # These come in a manually created JAR file, this rule is just wrapping it in
 # a java_import, so that it is a valid target for the 'resources' property of