[SDK] Makes --lazy_async_stack default.

Bug: dart-lang/sdk#42062
Change-Id: If22ed42b363e2d75d0be5cc14aef9e909b8ff2e6
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/149288
Commit-Queue: Clement Skau <[email protected]>
Reviewed-by: Martin Kustermann <[email protected]>

Author: Clement Skau

pkg/test_runner/lib/src/compiler_configuration.dart

@@ -1085,8 +1085,7 @@ class SpecParserCompilerConfiguration extends CompilerConfiguration {
 }
 
 abstract class VMKernelCompilerMixin {
-  static final noCausalAsyncStacksRegExp =
-      RegExp('--no[_-]causal[_-]async[_-]stacks');
+  static final causalAsyncStacksRegExp = RegExp('--causal[_-]async[_-]stacks');
 
   TestConfiguration get _configuration;
 
@@ -1117,7 +1116,7 @@ abstract class VMKernelCompilerMixin {
 
     var isProductMode = _configuration.configuration.mode == Mode.product;
 
-    var causalAsyncStacks = !arguments.any(noCausalAsyncStacksRegExp.hasMatch);
+    var causalAsyncStacks = arguments.any(causalAsyncStacksRegExp.hasMatch);
 
     var args = [
       _isAot ? '--aot' : '--no-aot',

runtime/vm/BUILD.gn

@@ -180,7 +180,7 @@ template("gen_vm_platform") {
       "$root_out_dir/vm_outline" + output_postfix + ".dill",
     ]
     args = [ "dart:core" ]
-    allow_causal_async_stacks = !is_product_flag
+    allow_causal_async_stacks = false
     args += [
       "-Ddart.vm.product=$is_product_flag",
       "-Ddart.developer.causal_async_stacks=$allow_causal_async_stacks",

runtime/vm/flag_list.h

@@ -55,8 +55,8 @@ constexpr bool kDartUseBackgroundCompilation = true;
 #define VM_GLOBAL_FLAG_LIST(P, R, C, D)                                        \
   P(dwarf_stack_traces_mode, bool, false,                                      \
     "Use --[no-]dwarf-stack-traces instead.")                                  \
-  P(causal_async_stacks, bool, !USING_PRODUCT, "Improved async stacks")        \
-  P(lazy_async_stacks, bool, false, "Reconstruct async stacks from listeners") \
+  P(causal_async_stacks, bool, false, "Improved async stacks")                 \
+  P(lazy_async_stacks, bool, true, "Reconstruct async stacks from listeners")  \
   P(lazy_dispatchers, bool, true, "Generate dispatchers lazily")               \
   P(use_bare_instructions, bool, true, "Enable bare instructions mode.")       \
   R(dedup_instructions, true, bool, false,                                     \