Add a test to ensure that no SwiftASTContext is initialized for setting a breakpoint.

rdar://81717792

Author: adrian-prantl

lldb/test/API/lang/swift/breakpoint_perf/Makefile

@@ -0,0 +1,2 @@
+SWIFT_SOURCES := main.swift
+include Makefile.rules

lldb/test/API/lang/swift/breakpoint_perf/TestSwiftBreakpointPerf.py

@@ -0,0 +1,31 @@
+import lldb
+from lldbsuite.test.decorators import *
+import lldbsuite.test.lldbtest as lldbtest
+import lldbsuite.test.lldbutil as lldbutil
+import unittest2
+
+class TestSwiftReflectionLoading(lldbtest.TestBase):
+    mydir = lldbtest.TestBase.compute_mydir(__file__)
+
+    @swiftTest
+    def test(self):
+        """Test that no SwiftASTContext is initialized just to stop at a breakpoint"""
+        self.build()
+
+        log = self.getBuildArtifact("types.log")
+        self.runCmd('log enable lldb types -f "%s"' % log)
+
+        target, process, thread, bkpt = lldbutil.run_to_source_breakpoint(
+            self, 'Set breakpoint here', lldb.SBFileSpec('main.swift'))
+
+        # Scan through the types log.
+        logfile = open(log, "r")
+        found_typeref = 0
+        found_astctx = 0
+        for line in logfile:
+            if 'TypeSystemSwiftTypeRef("a.out")::TypeSystemSwiftTypeRef()' in line:
+                found_typeref += 1
+            if 'SwiftASTContext' in line:
+                found_astctx += 1
+        self.assertEqual(found_typeref, 1)
+        self.assertEqual(found_astctx, 0)

lldb/test/API/lang/swift/breakpoint_perf/main.swift

@@ -0,0 +1,11 @@
+
+class C {
+  func f() {
+    {
+      print("hello from a complicated context") // Set breakpoint here
+    }()
+  }
+}
+
+let c = C()
+c.f()