make _sre fallback for TRegex configurable, so we can pass one shared-engine leak test

Author: timfel

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/builtins/modules/SREModuleBuiltins.java

@@ -65,6 +65,7 @@
 import com.oracle.graal.python.nodes.truffle.PythonArithmeticTypes;
 import com.oracle.graal.python.runtime.ExecutionContext.IndirectCallContext;
 import com.oracle.graal.python.runtime.PythonContext;
+import com.oracle.graal.python.runtime.PythonCore;
 import com.oracle.graal.python.runtime.PythonOptions;
 import com.oracle.graal.python.runtime.exception.PythonErrorType;
 import com.oracle.truffle.api.CompilerAsserts;
@@ -96,6 +97,12 @@ protected List<? extends NodeFactory<? extends PythonBuiltinBaseNode>> getNodeFa
         return SREModuleBuiltinsFactory.getFactories();
     }
 
+    @Override
+    public void initialize(PythonCore core) {
+        builtinConstants.put("_use_sre_fallback", core.getContext().getLanguage().getEngineOption(PythonOptions.TRegexUsesSREFallback));
+        super.initialize(core);
+    }
+
     @Builtin(name = "_build_regex_engine", minNumOfPositionalArgs = 1)
     @GenerateNodeFactory
     abstract static class BuildRegexEngine extends PythonUnaryBuiltinNode {

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/runtime/PythonOptions.java

@@ -173,9 +173,12 @@ private PythonOptions() {
 
     // disabling TRegex has an effect on the _sre Python functions that are
     // dynamically created, so we cannot change that option again.
-    @EngineOption @Option(category = OptionCategory.EXPERT, help = "Use the optimized TRegex engine and call the CPython sre engine only as a fallback. Default true") //
+    @EngineOption @Option(category = OptionCategory.EXPERT, help = "Use the optimized TRegex engine. Default true") //
     public static final OptionKey<Boolean> WithTRegex = new OptionKey<>(true);
 
+    @EngineOption @Option(category = OptionCategory.EXPERT, help = "Use the CPython sre engine as a fallback to the TRegex engine.") //
+    public static final OptionKey<Boolean> TRegexUsesSREFallback = new OptionKey<>(true);
+
     @Option(category = OptionCategory.EXPERT, help = "Switch on/off using lazy strings for performance reasons. Default true.") //
     public static final OptionKey<Boolean> LazyStrings = new OptionKey<>(true);
 

graalpython/lib-graalpython/_sre.py

@@ -134,8 +134,12 @@ def fallback_compiler(pattern, flags):
     if engine_builder:
         global TREGEX_ENGINE_STR
         global TREGEX_ENGINE_BYTES
-        TREGEX_ENGINE_STR = engine_builder("Flavor=PythonStr", configure_fallback_compiler("str"))
-        TREGEX_ENGINE_BYTES = engine_builder("Flavor=PythonBytes", configure_fallback_compiler("bytes"))
+        if _use_sre_fallback:
+            TREGEX_ENGINE_STR = engine_builder("Flavor=PythonStr", configure_fallback_compiler("str"))
+            TREGEX_ENGINE_BYTES = engine_builder("Flavor=PythonBytes", configure_fallback_compiler("bytes"))
+        else:
+            TREGEX_ENGINE_STR = engine_builder("Flavor=PythonStr")
+            TREGEX_ENGINE_BYTES = engine_builder("Flavor=PythonBytes")
 
         def new_compile(p, flags=0):
             if isinstance(p, (str, bytes)):

mx.graalpython/mx_graalpython.py

@@ -208,7 +208,7 @@ def punittest(ars):
         assert run_leak_launcher(["--lang", "python", "--code", "import _testcapi, mmap, bz2; print(memoryview(b'').nbytes)", "--forbidden-class", "com.oracle.graal.python.builtins.objects.object.PythonObject", "--python.ForceImportSite"]) == 0
 
         # test leaks with shared engine Python code only
-        assert run_leak_launcher(["--lang", "python", "--shared-engine", "--code", "pass", "--forbidden-class", "com.oracle.graal.python.builtins.objects.object.PythonObject", "--python.ForceImportSite"]) == 0
+        assert run_leak_launcher(["--lang", "python", "--shared-engine", "--code", "pass", "--forbidden-class", "com.oracle.graal.python.builtins.objects.object.PythonObject", "--python.ForceImportSite", "--python.TRegexUsesSREFallback=false"]) == 0
 
         # test leaks with shared engine when some C module code is involved
         # Not working due to GR-26175