# This Source Code Form is subject to the terms of the Mozilla Public
# License, v. 2.0. If a copy of the MPL was not distributed with this file,
# You can obtain one at http://mozilla.org/MPL/2.0/.

# Pretty-printers for InterpreterRegs.

import gdb

from mozilla import prettyprinters

prettyprinters.clear_module_printers(__name__)

from mozilla.prettyprinters import pretty_printer


class InterpreterTypeCache:
    # Cache information about the Interpreter types for this objfile.
    def __init__(self):
        self.tValue = gdb.lookup_type("JS::Value")
        self.tJSOp = gdb.lookup_type("JSOp")
        try:
            self.tScriptFrameIterData = gdb.lookup_type("js::ScriptFrameIter::Data")
        except gdb.error:
            # Work around problem with gcc optimized debuginfo where it doesn't
            # seem to be able to see that ScriptFrameIter inherits the
            # FrameIter::Data type.
            self.tScriptFrameIterData = gdb.lookup_type("js::FrameIter::Data")
        self.tInterpreterFrame = gdb.lookup_type("js::InterpreterFrame")
        self.tBaselineFrame = gdb.lookup_type("js::jit::BaselineFrame")
        self.tRematerializedFrame = gdb.lookup_type("js::jit::RematerializedFrame")
        self.tDebugFrame = gdb.lookup_type("js::wasm::DebugFrame")


@pretty_printer("js::InterpreterRegs")
class InterpreterRegs:
    def __init__(self, value, cache):
        self.value = value
        self.cache = cache
        if not cache.mod_Interpreter:
            cache.mod_Interpreter = InterpreterTypeCache()
        self.itc = cache.mod_Interpreter

    # There's basically no way to co-operate with 'set print pretty' (how would
    # you get the current level of indentation?), so we don't even bother
    # trying. No 'children', just 'to_string'.
    def to_string(self):
        fp_ = "fp_ = {}".format(self.value["fp_"])
        slots = (self.value["fp_"] + 1).cast(self.itc.tValue.pointer())
        sp = "sp = fp_.slots() + {}".format(self.value["sp"] - slots)
        pc = "pc = {}".format(self.value["pc"])
        return f"{{ {fp_}, {sp}, {pc} }}"


@pretty_printer("js::AbstractFramePtr")
class AbstractFramePtr:
    Tag_InterpreterFrame = 0x0
    Tag_BaselineFrame = 0x1
    Tag_RematerializedFrame = 0x2
    Tag_WasmDebugFrame = 0x3
    TagMask = 0x3

    def __init__(self, value, cache):
        self.value = value
        self.cache = cache
        if not cache.mod_Interpreter:
            cache.mod_Interpreter = InterpreterTypeCache()
        self.itc = cache.mod_Interpreter

    def to_string(self):
        ptr = self.value["ptr_"]
        tag = ptr & AbstractFramePtr.TagMask
        ptr = ptr & ~AbstractFramePtr.TagMask
        if tag == AbstractFramePtr.Tag_InterpreterFrame:
            label = "js::InterpreterFrame"
            ptr = ptr.cast(self.itc.tInterpreterFrame.pointer())
        if tag == AbstractFramePtr.Tag_BaselineFrame:
            label = "js::jit::BaselineFrame"
            ptr = ptr.cast(self.itc.tBaselineFrame.pointer())
        if tag == AbstractFramePtr.Tag_RematerializedFrame:
            label = "js::jit::RematerializedFrame"
            ptr = ptr.cast(self.itc.tRematerializedFrame.pointer())
        if tag == AbstractFramePtr.Tag_WasmDebugFrame:
            label = "js::wasm::DebugFrame"
            ptr = ptr.cast(self.itc.tDebugFrame.pointer())
        return f"AbstractFramePtr (({label} *) {ptr})"

    # Provide the ptr_ field as a child, so it prints after the pretty string
    # provided above.
    def children(self):
        yield ("ptr_", self.value["ptr_"])