xref: /llvm-project/lldb/test/API/commands/expression/weak_symbols/TestWeakSymbols.py (revision 2238dcc39358353cac21df75c3c3286ab20b8f53)

"""
Test that we can compile expressions referring to
absent weak symbols from a dylib.
"""


import os
import lldb
from lldbsuite.test.decorators import *
import lldbsuite.test.lldbutil as lldbutil
from lldbsuite.test.lldbtest import *


class TestWeakSymbolsInExpressions(TestBase):
    NO_DEBUG_INFO_TESTCASE = True

    @skipUnlessDarwin
    @skipIf(compiler="clang", compiler_version=["<", "7.0"])
    def test_weak_symbol_in_expr(self):
        """Tests that we can refer to weak symbols in expressions."""
        self.build()
        self.main_source_file = lldb.SBFileSpec("main.c")
        self.do_test()

    def run_weak_var_check(self, weak_varname, present):
        # The expression will modify present_weak_int to signify which branch
        # was taken.  Set it to so we don't get confused by a previous run.
        value = self.target.FindFirstGlobalVariable("present_weak_int")
        value.SetValueFromCString("0")
        if present:
            correct_value = 10
        else:
            correct_value = 20

        # Note, I'm adding the "; 10" at the end of the expression to work around
        # the bug that expressions with no result currently return False for Success()...
        expr = (
            "if (&"
            + weak_varname
            + " != NULL) { present_weak_int = 10; } else { present_weak_int = 20;}; 10"
        )
        result = self.frame.EvaluateExpression(expr)
        self.assertSuccess(result.GetError(), "absent_weak_int expr failed")
        self.assertEqual(
            value.GetValueAsSigned(),
            correct_value,
            "Didn't change present_weak_int correctly.",
        )

    def do_test(self):
        hidden_dir = os.path.join(self.getBuildDir(), "hidden")
        hidden_dylib = os.path.join(hidden_dir, "libdylib.dylib")

        launch_info = lldb.SBLaunchInfo(None)
        launch_info.SetWorkingDirectory(self.getBuildDir())
        launch_info.SetLaunchFlags(lldb.eLaunchFlagInheritTCCFromParent)

        (self.target, _, thread, _) = lldbutil.run_to_source_breakpoint(
            self,
            "Set a breakpoint here",
            self.main_source_file,
            launch_info=launch_info,
            extra_images=[hidden_dylib],
        )
        # First we have to import the Dylib module so we get the type info
        # for the weak symbol.  We need to add the source dir to the module
        # search paths, and then run @import to introduce it into the expression
        # context:
        self.dbg.HandleCommand(
            "settings set target.clang-module-search-paths " + self.getSourceDir()
        )

        self.frame = thread.frames[0]
        self.assertTrue(self.frame.IsValid(), "Got a good frame")
        options = lldb.SBExpressionOptions()
        options.SetLanguage(lldb.eLanguageTypeObjC)
        result = self.frame.EvaluateExpression("@import Dylib", options)

        # Now run an expression that references an absent weak symbol:
        self.run_weak_var_check("absent_weak_int", False)
        self.run_weak_var_check("absent_weak_function", False)

        # Make sure we can do the same thing with present weak symbols
        self.run_weak_var_check("present_weak_int", True)
        self.run_weak_var_check("present_weak_function", True)