Add a testcase for protected imports.

lldb/test/API/lang/swift/import_spi/A.swift

@@ -0,0 +1,6 @@
+@_spi(Private) import B
+public class FromA {
+  public init() {}
+  @_spi(Private) public var a : Int { get { return 42 } }
+  @_spi(Private) public var b : FromB { get { return FromB() } }
+}

lldb/test/API/lang/swift/import_spi/B.swift

@@ -0,0 +1,4 @@
+public class FromB {
+  public init() {}
+  public let c = 42
+}

lldb/test/API/lang/swift/import_spi/Makefile

@@ -0,0 +1,24 @@
+SWIFT_SOURCES := main.swift
+MODULENAME = Main
+SWIFTFLAGS_EXTRAS = -I$(BUILDDIR)
+LD_EXTRAS = -L$(BUILDDIR) -lA -lB
+
+all: A.swiftmodule $(EXE)
+
+include Makefile.rules
+
+A.swiftmodule: $(SRCDIR)/A.swift B.swiftmodule
+	$(MAKE) -f $(MAKEFILE_RULES) \
+		DYLIB_ONLY=YES \
+		DYLIB_NAME=A \
+		DYLIB_SWIFT_SOURCES=A.swift \
+		DYLIB_MODULENAME=A \
+		SWIFTFLAGS_EXTRAS=-I$(BUILDDIR) \
+		LD_EXTRAS="-L$(BUILDDIR) -lB"
+
+B.swiftmodule: $(SRCDIR)/B.swift
+	$(MAKE) -f $(MAKEFILE_RULES) \
+		DYLIB_ONLY=YES \
+		DYLIB_NAME=B \
+		DYLIB_SWIFT_SOURCES=B.swift \
+		DYLIB_MODULENAME=B

lldb/test/API/lang/swift/import_spi/TestSwiftImportSPI.py

@@ -0,0 +1,19 @@
+import lldb
+from lldbsuite.test.decorators import *
+import lldbsuite.test.lldbtest as lldbtest
+import lldbsuite.test.lldbutil as lldbutil
+import os
+
+
+class TestSwiftImportSPI(lldbtest.TestBase):
+    @swiftTest
+    def test(self):
+        """Test SPI imports"""
+        self.build()
+        target, process, thread, bkpt = lldbutil.run_to_source_breakpoint(
+            self, 'break here', lldb.SBFileSpec('main.swift'),
+            extra_images=['A', 'B'])
+        # a.b returns a B FromB, which is an @_spi(Private) import of A.
+        self.expect("expression -- a.b.c", substrs=['42'])
+        # a.a itself is marked @_spi(Private).
+        self.expect("expression -- a.a", substrs=['42'])

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

@@ -0,0 +1,4 @@
+import A
+
+let a = FromA()
+print("break here")