a28e7f1aad
Extend support in LLDB for WebAssembly. This PR adds a new Process plugin (ProcessWasm) that extends ProcessGDBRemote for WebAssembly targets. It adds support for WebAssembly's memory model with separate address spaces, and the ability to fetch the call stack from the WebAssembly runtime. I have tested this change with the WebAssembly Micro Runtime (WAMR, https://github.com/bytecodealliance/wasm-micro-runtime) which implements a GDB debug stub and supports the qWasmCallStack packet. ``` (lldb) process connect --plugin wasm connect://localhost:4567 Process 1 stopped * thread #1, name = 'nobody', stop reason = trace frame #0: 0x40000000000001ad wasm32_args.wasm`main: -> 0x40000000000001ad <+3>: global.get 0 0x40000000000001b3 <+9>: i32.const 16 0x40000000000001b5 <+11>: i32.sub 0x40000000000001b6 <+12>: local.set 0 (lldb) b add Breakpoint 1: where = wasm32_args.wasm`add + 28 at test.c:4:12, address = 0x400000000000019c (lldb) c Process 1 resuming Process 1 stopped * thread #1, name = 'nobody', stop reason = breakpoint 1.1 frame #0: 0x400000000000019c wasm32_args.wasm`add(a=<unavailable>, b=<unavailable>) at test.c:4:12 1 int 2 add(int a, int b) 3 { -> 4 return a + b; 5 } 6 7 int (lldb) bt * thread #1, name = 'nobody', stop reason = breakpoint 1.1 * frame #0: 0x400000000000019c wasm32_args.wasm`add(a=<unavailable>, b=<unavailable>) at test.c:4:12 frame #1: 0x40000000000001e5 wasm32_args.wasm`main at test.c:12:12 frame #2: 0x40000000000001fe wasm32_args.wasm ``` This PR is based on an unmerged patch from Paolo Severini: https://reviews.llvm.org/D78801. I intentionally stuck to the foundations to keep this PR small. I have more PRs in the pipeline to support the other features/packets. My motivation for supporting Wasm is to support debugging Swift compiled to WebAssembly: https://www.swift.org/documentation/articles/wasm-getting-started.html
291 lines
10 KiB
Python
291 lines
10 KiB
Python
import lldb
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import binascii
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from lldbsuite.test.lldbtest import *
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from lldbsuite.test.decorators import *
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from lldbsuite.test.gdbclientutils import *
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from lldbsuite.test.lldbgdbclient import GDBRemoteTestBase
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LLDB_INVALID_ADDRESS = lldb.LLDB_INVALID_ADDRESS
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load_address = 0x400000000
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def format_register_value(val):
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"""
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Encode each byte by two hex digits in little-endian order.
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"""
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result = ""
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mask = 0xFF
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shift = 0
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for i in range(0, 8):
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x = (val & mask) >> shift
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result += format(x, "02x")
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mask <<= 8
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shift += 8
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return result
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class MyResponder(MockGDBServerResponder):
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current_pc = load_address + 0x0A
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def __init__(self, obj_path, module_name=""):
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self._obj_path = obj_path
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self._module_name = module_name or obj_path
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MockGDBServerResponder.__init__(self)
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def respond(self, packet):
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if packet[0:13] == "qRegisterInfo":
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return self.qRegisterInfo(packet[13:])
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if packet.startswith("qWasmCallStack"):
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return self.qWasmCallStack()
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return MockGDBServerResponder.respond(self, packet)
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def qSupported(self, client_supported):
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return "qXfer:libraries:read+;PacketSize=1000;vContSupported-"
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def qHostInfo(self):
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return ""
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def QEnableErrorStrings(self):
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return ""
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def qfThreadInfo(self):
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return "m1,"
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def qRegisterInfo(self, index):
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if index == 0:
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return "name:pc;alt-name:pc;bitsize:64;offset:0;encoding:uint;format:hex;set:General Purpose Registers;gcc:16;dwarf:16;generic:pc;"
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return "E45"
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def qProcessInfo(self):
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return "pid:1;ppid:1;uid:1;gid:1;euid:1;egid:1;name:%s;triple:%s;ptrsize:4" % (
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hex_encode_bytes("lldb"),
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hex_encode_bytes("wasm32-unknown-unknown-wasm"),
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)
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def haltReason(self):
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return "T02thread:1;"
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def readRegister(self, register):
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return format_register_value(self.current_pc)
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def qXferRead(self, obj, annex, offset, length):
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if obj == "libraries":
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xml = (
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'<library-list><library name="%s"><section address="%d"/></library></library-list>'
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% (self._module_name, load_address)
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)
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return xml, False
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else:
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return None, False
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def readMemory(self, addr, length):
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if addr < load_address:
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return "E02"
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result = ""
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with open(self._obj_path, mode="rb") as file:
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file_content = bytearray(file.read())
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addr_from = addr - load_address
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addr_to = addr_from + min(length, len(file_content) - addr_from)
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for i in range(addr_from, addr_to):
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result += format(file_content[i], "02x")
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file.close()
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return result
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def qWasmCallStack(self):
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# Return two 64-bit addresses: 0x40000000000001B3, 0x40000000000001FE
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return "b301000000000040fe01000000000040"
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class TestWasm(GDBRemoteTestBase):
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@skipIfAsan
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@skipIfXmlSupportMissing
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def test_load_module_with_embedded_symbols_from_remote(self):
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"""Test connecting to a WebAssembly engine via GDB-remote and loading a Wasm module with embedded DWARF symbols"""
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yaml_path = "test_wasm_embedded_debug_sections.yaml"
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yaml_base, ext = os.path.splitext(yaml_path)
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obj_path = self.getBuildArtifact(yaml_base)
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self.yaml2obj(yaml_path, obj_path)
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self.server.responder = MyResponder(obj_path, "test_wasm")
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target = self.dbg.CreateTarget("")
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process = self.connect(target, "wasm")
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lldbutil.expect_state_changes(
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self, self.dbg.GetListener(), process, [lldb.eStateStopped]
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)
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num_modules = target.GetNumModules()
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self.assertEqual(1, num_modules)
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module = target.GetModuleAtIndex(0)
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num_sections = module.GetNumSections()
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self.assertEqual(5, num_sections)
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code_section = module.GetSectionAtIndex(0)
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self.assertEqual("code", code_section.GetName())
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self.assertEqual(
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load_address | code_section.GetFileOffset(),
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code_section.GetLoadAddress(target),
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)
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debug_info_section = module.GetSectionAtIndex(1)
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self.assertEqual(".debug_info", debug_info_section.GetName())
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self.assertEqual(
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load_address | debug_info_section.GetFileOffset(),
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debug_info_section.GetLoadAddress(target),
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)
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debug_abbrev_section = module.GetSectionAtIndex(2)
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self.assertEqual(".debug_abbrev", debug_abbrev_section.GetName())
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self.assertEqual(
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load_address | debug_abbrev_section.GetFileOffset(),
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debug_abbrev_section.GetLoadAddress(target),
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)
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debug_line_section = module.GetSectionAtIndex(3)
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self.assertEqual(".debug_line", debug_line_section.GetName())
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self.assertEqual(
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load_address | debug_line_section.GetFileOffset(),
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debug_line_section.GetLoadAddress(target),
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)
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debug_str_section = module.GetSectionAtIndex(4)
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self.assertEqual(".debug_str", debug_str_section.GetName())
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self.assertEqual(
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load_address | debug_line_section.GetFileOffset(),
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debug_line_section.GetLoadAddress(target),
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)
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@skipIfAsan
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@skipIfXmlSupportMissing
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def test_load_module_with_stripped_symbols_from_remote(self):
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"""Test connecting to a WebAssembly engine via GDB-remote and loading a Wasm module with symbols stripped into a separate Wasm file"""
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sym_yaml_path = "test_sym.yaml"
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sym_yaml_base, ext = os.path.splitext(sym_yaml_path)
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sym_obj_path = self.getBuildArtifact(sym_yaml_base) + ".wasm"
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self.yaml2obj(sym_yaml_path, sym_obj_path)
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yaml_path = "test_wasm_external_debug_sections.yaml"
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yaml_base, ext = os.path.splitext(yaml_path)
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obj_path = self.getBuildArtifact(yaml_base) + ".wasm"
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self.yaml2obj(yaml_path, obj_path)
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self.server.responder = MyResponder(obj_path, "test_wasm")
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folder, _ = os.path.split(obj_path)
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self.runCmd(
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"settings set target.debug-file-search-paths " + os.path.abspath(folder)
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)
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target = self.dbg.CreateTarget("")
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process = self.connect(target, "wasm")
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lldbutil.expect_state_changes(
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self, self.dbg.GetListener(), process, [lldb.eStateStopped]
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)
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num_modules = target.GetNumModules()
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self.assertEqual(1, num_modules)
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module = target.GetModuleAtIndex(0)
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num_sections = module.GetNumSections()
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self.assertEqual(5, num_sections)
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code_section = module.GetSectionAtIndex(0)
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self.assertEqual("code", code_section.GetName())
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self.assertEqual(
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load_address | code_section.GetFileOffset(),
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code_section.GetLoadAddress(target),
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)
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debug_info_section = module.GetSectionAtIndex(1)
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self.assertEqual(".debug_info", debug_info_section.GetName())
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self.assertEqual(
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LLDB_INVALID_ADDRESS, debug_info_section.GetLoadAddress(target)
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)
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debug_abbrev_section = module.GetSectionAtIndex(2)
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self.assertEqual(".debug_abbrev", debug_abbrev_section.GetName())
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self.assertEqual(
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LLDB_INVALID_ADDRESS, debug_abbrev_section.GetLoadAddress(target)
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)
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debug_line_section = module.GetSectionAtIndex(3)
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self.assertEqual(".debug_line", debug_line_section.GetName())
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self.assertEqual(
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LLDB_INVALID_ADDRESS, debug_line_section.GetLoadAddress(target)
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)
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debug_str_section = module.GetSectionAtIndex(4)
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self.assertEqual(".debug_str", debug_str_section.GetName())
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self.assertEqual(
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LLDB_INVALID_ADDRESS, debug_line_section.GetLoadAddress(target)
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)
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@skipIfAsan
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@skipIfXmlSupportMissing
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def test_load_module_from_file(self):
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"""Test connecting to a WebAssembly engine via GDB-remote and loading a Wasm module from a file"""
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yaml_path = "test_wasm_embedded_debug_sections.yaml"
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yaml_base, ext = os.path.splitext(yaml_path)
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obj_path = self.getBuildArtifact(yaml_base)
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self.yaml2obj(yaml_path, obj_path)
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self.server.responder = MyResponder(obj_path)
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target = self.dbg.CreateTarget("")
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process = self.connect(target, "wasm")
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lldbutil.expect_state_changes(
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self, self.dbg.GetListener(), process, [lldb.eStateStopped]
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)
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num_modules = target.GetNumModules()
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self.assertEqual(1, num_modules)
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module = target.GetModuleAtIndex(0)
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num_sections = module.GetNumSections()
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self.assertEqual(5, num_sections)
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code_section = module.GetSectionAtIndex(0)
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self.assertEqual("code", code_section.GetName())
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self.assertEqual(
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load_address | code_section.GetFileOffset(),
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code_section.GetLoadAddress(target),
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)
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debug_info_section = module.GetSectionAtIndex(1)
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self.assertEqual(".debug_info", debug_info_section.GetName())
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self.assertEqual(
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LLDB_INVALID_ADDRESS, debug_info_section.GetLoadAddress(target)
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)
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debug_abbrev_section = module.GetSectionAtIndex(2)
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self.assertEqual(".debug_abbrev", debug_abbrev_section.GetName())
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self.assertEqual(
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LLDB_INVALID_ADDRESS, debug_abbrev_section.GetLoadAddress(target)
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)
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debug_line_section = module.GetSectionAtIndex(3)
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self.assertEqual(".debug_line", debug_line_section.GetName())
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self.assertEqual(
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LLDB_INVALID_ADDRESS, debug_line_section.GetLoadAddress(target)
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)
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debug_str_section = module.GetSectionAtIndex(4)
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self.assertEqual(".debug_str", debug_str_section.GetName())
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self.assertEqual(
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LLDB_INVALID_ADDRESS, debug_line_section.GetLoadAddress(target)
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)
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thread = process.GetThreadAtIndex(0)
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self.assertTrue(thread.IsValid())
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frame = thread.GetFrameAtIndex(0)
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self.assertTrue(frame.IsValid())
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self.assertEqual(frame.GetPC(), 0x40000000000001B3)
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frame = thread.GetFrameAtIndex(1)
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self.assertTrue(frame.IsValid())
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self.assertEqual(frame.GetPC(), 0x40000000000001FE)
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