"""Check that compiler-generated register values work correctly"""

import re
import lldb
from lldbsuite.test.decorators import *
from lldbsuite.test.lldbtest import *
from lldbsuite.test import lldbutil


def re_expr_equals(val_type, val):
    # Match ({val_type}) ${sum_digits} = {val}
    return re.compile(r"\(" + val_type + r"\) \$\d+ = " + str(val))


class RegisterVariableTestCase(TestBase):
    @expectedFailureAll(compiler="clang", compiler_version=["<", "3.5"])
    @expectedFailureAll(
        compiler="gcc", compiler_version=[">=", "4.8.2"], archs=["i386"]
    )
    @expectedFailureAll(compiler="gcc", compiler_version=["<", "4.9"], archs=["x86_64"])
    def test_and_run_command(self):
        """Test expressions on register values."""

        # This test now ensures that each probable
        # register variable location is actually a register, and
        # if so, whether we can print out the variable there.
        # It only requires one of them to be handled in a non-error
        # way.
        register_variables_count = 0

        self.build()
        exe = self.getBuildArtifact("a.out")
        self.runCmd("file " + exe, CURRENT_EXECUTABLE_SET)

        # Break inside the main.
        lldbutil.run_break_set_by_source_regexp(self, "break", num_expected_locations=3)

        ####################
        # First breakpoint

        self.runCmd("run", RUN_SUCCEEDED)

        # The stop reason of the thread should be breakpoint.
        self.expect(
            "thread list",
            STOPPED_DUE_TO_BREAKPOINT,
            substrs=["stopped", "stop reason = breakpoint"],
        )

        # The breakpoint should have a hit count of 1.
        lldbutil.check_breakpoint(
            self, bpno=1, location_id=1, expected_location_hit_count=1
        )

        # Try some variables that should be visible
        frame = (
            self.dbg.GetSelectedTarget()
            .GetProcess()
            .GetSelectedThread()
            .GetSelectedFrame()
        )
        if self.is_variable_in_register(frame, "a"):
            register_variables_count += 1
            self.expect(
                "expr a",
                VARIABLES_DISPLAYED_CORRECTLY,
                patterns=[re_expr_equals("int", 2)],
            )

        if self.is_struct_pointer_in_register(frame, "b", self.TraceOn()):
            register_variables_count += 1
            self.expect(
                "expr b->m1",
                VARIABLES_DISPLAYED_CORRECTLY,
                patterns=[re_expr_equals("int", 3)],
            )

        #####################
        # Second breakpoint

        self.runCmd("continue")

        # The stop reason of the thread should be breakpoint.
        self.expect(
            "thread list",
            STOPPED_DUE_TO_BREAKPOINT,
            substrs=["stopped", "stop reason = breakpoint"],
        )

        # The breakpoint should have a hit count of 1.
        lldbutil.check_breakpoint(
            self, bpno=1, location_id=2, expected_location_hit_count=1
        )

        # Try some variables that should be visible
        frame = (
            self.dbg.GetSelectedTarget()
            .GetProcess()
            .GetSelectedThread()
            .GetSelectedFrame()
        )
        if self.is_struct_pointer_in_register(frame, "b", self.TraceOn()):
            register_variables_count += 1
            self.expect(
                "expr b->m2",
                VARIABLES_DISPLAYED_CORRECTLY,
                patterns=[re_expr_equals("int", 5)],
            )

        if self.is_variable_in_register(frame, "c"):
            register_variables_count += 1
            self.expect(
                "expr c",
                VARIABLES_DISPLAYED_CORRECTLY,
                patterns=[re_expr_equals("int", 5)],
            )

        #####################
        # Third breakpoint

        self.runCmd("continue")

        # The stop reason of the thread should be breakpoint.
        self.expect(
            "thread list",
            STOPPED_DUE_TO_BREAKPOINT,
            substrs=["stopped", "stop reason = breakpoint"],
        )

        # The breakpoint should have a hit count of 1.
        lldbutil.check_breakpoint(
            self, bpno=1, location_id=3, expected_location_hit_count=1
        )

        # Try some variables that should be visible
        frame = (
            self.dbg.GetSelectedTarget()
            .GetProcess()
            .GetSelectedThread()
            .GetSelectedFrame()
        )
        if self.is_variable_in_register(frame, "f"):
            register_variables_count += 1
            self.expect(
                "expr f",
                VARIABLES_DISPLAYED_CORRECTLY,
                patterns=[re_expr_equals("float", "3.1")],
            )

        # Validate that we verified at least one register variable
        self.assertGreater(
            register_variables_count,
            0,
            "expected to verify at least one variable in a register",
        )
        self.trace(
            "executed {} expressions with values in registers".format(
                register_variables_count
            )
        )

        self.runCmd("kill")

    def is_variable_in_register(self, frame, var_name):
        # Ensure we can lookup the variable.
        var = frame.FindVariable(var_name)
        self.trace("\nchecking {}...".format(var_name))
        if var is None or not var.IsValid():
            self.trace("{} cannot be found".format(var_name))
            return False

        # Check that we can get its value.  If not, this
        # may be a variable that is just out of scope at this point.
        value = var.GetValue()
        self.trace("checking value...")
        if value is None:
            self.trace("value is invalid")
            return False
        else:
            self.trace("value is {}".format(value))

        # We have a variable and we can get its value.  The variable is in a
        # register if we cannot get an address for it, assuming it is not a
        # struct pointer.  (This is an approximation - compilers can do other
        # things with spitting up a value into multiple parts of multiple
        # registers, but what we're verifying here is much more than it was
        # doing before).
        var_addr = var.GetAddress()
        self.trace("checking address...")
        if var_addr.IsValid():
            # We have an address, it must not be in a register.
            self.trace(
                "var {} is not in a register: has a valid address {}".format(
                    var_name, var_addr
                )
            )
            return False
        else:
            # We don't have an address but we can read the value.
            # It is likely stored in a register.
            self.trace(
                "var {} is in a register (we don't have an address for it)".format(
                    var_name
                )
            )
            return True

    def is_struct_pointer_in_register(self, frame, var_name, trace):
        # Ensure we can lookup the variable.
        var = frame.FindVariable(var_name)
        if trace:
            print("\nchecking {}...".format(var_name))

        if var is None or not var.IsValid():
            self.trace("{} cannot be found".format(var_name))
            return False

        # Check that we can get its value.  If not, this
        # may be a variable that is just out of scope at this point.
        value = var.GetValue()
        self.trace("checking value...")
        if value is None:
            if trace:
                print("value is invalid")
            return False
        else:
            if trace:
                print("value is {}".format(value))

        var_loc = var.GetLocation()
        if trace:
            print("checking location: {}".format(var_loc))
        if var_loc is None or var_loc.startswith("0x"):
            # The frame var is not in a register but rather a memory location.
            self.trace("frame var {} is not in a register".format(var_name))
            return False
        else:
            self.trace("frame var {} is in a register".format(var_name))
            return True
