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debug: replace RtlCaptureStackBackTrace (which was spuriously failing…
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…) with a new implementation which uses RtlVirtualUnwind instead (#12740)

windows: add RtlCaptureContext, RtlLookupFunctionEntry, RtlVirtualUnwind and supporting types
windows: fix alignment of CONTEXT structs to match winnt.h as required by RtlCaptureContext (fxsave instr)
windows aarch64: fix __chkstk being defined twice if libc is not linked on msvc

Co-authored-by: Jakub Konka <[email protected]>
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@kcbanner @kubkon
kcbanner and kubkon authored Jan 4, 2023
1 parent a3e2ee0 commit 09ff03a
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Showing 4 changed files with 211 additions and 13 deletions.
53 changes: 45 additions & 8 deletions lib/std/debug.zig
View file
Original file line number Diff line number Diff line change
Expand Up @@ -206,17 +206,12 @@ pub fn captureStackTrace(first_address: ?usize, stack_trace: *std.builtin.StackT
if (native_os == .windows) {
const addrs = stack_trace.instruction_addresses;
const first_addr = first_address orelse {
stack_trace.index = windows.ntdll.RtlCaptureStackBackTrace(
0,
@intCast(u32, addrs.len),
@ptrCast(**anyopaque, addrs.ptr),
null,
);
stack_trace.index = walkStackWindows(addrs[0..]);
return;
};
var addr_buf_stack: [32]usize = undefined;
const addr_buf = if (addr_buf_stack.len > addrs.len) addr_buf_stack[0..] else addrs;
const n = windows.ntdll.RtlCaptureStackBackTrace(0, @intCast(u32, addr_buf.len), @ptrCast(**anyopaque, addr_buf.ptr), null);
const n = walkStackWindows(addr_buf[0..]);
const first_index = for (addr_buf[0..n]) |addr, i| {
if (addr == first_addr) {
break i;
Expand Down Expand Up @@ -573,14 +568,56 @@ pub fn writeCurrentStackTrace(
}
}

pub noinline fn walkStackWindows(addresses: []usize) usize {
if (builtin.cpu.arch == .x86) {
// RtlVirtualUnwind doesn't exist on x86
return windows.ntdll.RtlCaptureStackBackTrace(0, addresses.len, @ptrCast(**anyopaque, addresses.ptr), null);
}

const tib = @ptrCast(*const windows.NT_TIB, &windows.teb().Reserved1);

var context: windows.CONTEXT = std.mem.zeroes(windows.CONTEXT);
windows.ntdll.RtlCaptureContext(&context);

var i: usize = 0;
var image_base: usize = undefined;
var history_table: windows.UNWIND_HISTORY_TABLE = std.mem.zeroes(windows.UNWIND_HISTORY_TABLE);

while (i < addresses.len) : (i += 1) {
const current_regs = context.getRegs();
if (windows.ntdll.RtlLookupFunctionEntry(current_regs.ip, &image_base, &history_table)) |runtime_function| {
var handler_data: ?*anyopaque = null;
var establisher_frame: u64 = undefined;
_ = windows.ntdll.RtlVirtualUnwind(windows.UNW_FLAG_NHANDLER, image_base, current_regs.ip, runtime_function, &context, &handler_data, &establisher_frame, null);
} else {
// leaf function
context.setIp(@intToPtr(*u64, current_regs.sp).*);
context.setSp(current_regs.sp + @sizeOf(usize));
}

const next_regs = context.getRegs();
if (next_regs.sp < @ptrToInt(tib.StackLimit) or next_regs.sp > @ptrToInt(tib.StackBase)) {
break;
}

if (next_regs.ip == 0) {
break;
}

addresses[i] = next_regs.ip;
}

return i;
}

pub fn writeCurrentStackTraceWindows(
out_stream: anytype,
debug_info: *DebugInfo,
tty_config: TTY.Config,
start_addr: ?usize,
) !void {
var addr_buf: [1024]usize = undefined;
const n = windows.ntdll.RtlCaptureStackBackTrace(0, addr_buf.len, @ptrCast(**anyopaque, &addr_buf), null);
const n = walkStackWindows(addr_buf[0..]);
const addrs = addr_buf[0..n];
var start_i: usize = if (start_addr) |saddr| blk: {
for (addrs) |addr, i| {
Expand Down
124 changes: 119 additions & 5 deletions lib/std/os/windows.zig
View file
Original file line number Diff line number Diff line change
Expand Up @@ -31,6 +31,8 @@ pub const winmm = @import("windows/winmm.zig");

pub const self_process_handle = @intToPtr(HANDLE, maxInt(usize));

const Self = @This();

pub const OpenError = error{
IsDir,
NotDir,
Expand Down Expand Up @@ -3282,7 +3284,7 @@ pub usingnamespace switch (native_arch) {
};

pub const CONTEXT = extern struct {
P1Home: DWORD64,
P1Home: DWORD64 align(16),
P2Home: DWORD64,
P3Home: DWORD64,
P4Home: DWORD64,
Expand Down Expand Up @@ -3352,9 +3354,28 @@ pub usingnamespace switch (native_arch) {
LastExceptionToRip: DWORD64,
LastExceptionFromRip: DWORD64,

pub fn getRegs(ctx: *const CONTEXT) struct { bp: usize, ip: usize } {
return .{ .bp = ctx.Rbp, .ip = ctx.Rip };
pub fn getRegs(ctx: *const CONTEXT) struct { bp: usize, ip: usize, sp: usize } {
return .{ .bp = ctx.Rbp, .ip = ctx.Rip, .sp = ctx.Rsp };
}

pub fn setIp(ctx: *CONTEXT, ip: usize) void {
ctx.Rip = ip;
}

pub fn setSp(ctx: *CONTEXT, sp: usize) void {
ctx.Rsp = sp;
}
};

pub const RUNTIME_FUNCTION = extern struct {
BeginAddress: DWORD,
EndAddress: DWORD,
UnwindData: DWORD,
};

pub const KNONVOLATILE_CONTEXT_POINTERS = extern struct {
FloatingContext: [16]?*M128A,
IntegerContext: [16]?*ULONG64,
};
},
.aarch64 => struct {
Expand All @@ -3370,7 +3391,7 @@ pub usingnamespace switch (native_arch) {
};

pub const CONTEXT = extern struct {
ContextFlags: ULONG,
ContextFlags: ULONG align(16),
Cpsr: ULONG,
DUMMYUNIONNAME: extern union {
DUMMYSTRUCTNAME: extern struct {
Expand Down Expand Up @@ -3418,12 +3439,60 @@ pub usingnamespace switch (native_arch) {
Wcr: [2]DWORD,
Wvr: [2]DWORD64,

pub fn getRegs(ctx: *const CONTEXT) struct { bp: usize, ip: usize } {
pub fn getRegs(ctx: *const CONTEXT) struct { bp: usize, ip: usize, sp: usize } {
return .{
.bp = ctx.DUMMYUNIONNAME.DUMMYSTRUCTNAME.Fp,
.ip = ctx.Pc,
.sp = ctx.Sp,
};
}

pub fn setIp(ctx: *CONTEXT, ip: usize) void {
ctx.Pc = ip;
}

pub fn setSp(ctx: *CONTEXT, sp: usize) void {
ctx.Sp = sp;
}
};

pub const RUNTIME_FUNCTION = extern struct {
BeginAddress: DWORD,
DUMMYUNIONNAME: extern union {
UnwindData: DWORD,
DUMMYSTRUCTNAME: packed struct {
Flag: u2,
FunctionLength: u11,
RegF: u3,
RegI: u4,
H: u1,
CR: u2,
FrameSize: u9,
},
},
};

pub const KNONVOLATILE_CONTEXT_POINTERS = extern struct {
X19: ?*DWORD64,
X20: ?*DWORD64,
X21: ?*DWORD64,
X22: ?*DWORD64,
X23: ?*DWORD64,
X24: ?*DWORD64,
X25: ?*DWORD64,
X26: ?*DWORD64,
X27: ?*DWORD64,
X28: ?*DWORD64,
Fp: ?*DWORD64,
Lr: ?*DWORD64,
D8: ?*DWORD64,
D9: ?*DWORD64,
D10: ?*DWORD64,
D11: ?*DWORD64,
D12: ?*DWORD64,
D13: ?*DWORD64,
D14: ?*DWORD64,
D15: ?*DWORD64,
};
},
else => struct {},
Expand All @@ -3436,6 +3505,36 @@ pub const EXCEPTION_POINTERS = extern struct {

pub const VECTORED_EXCEPTION_HANDLER = *const fn (ExceptionInfo: *EXCEPTION_POINTERS) callconv(WINAPI) c_long;

pub const EXCEPTION_DISPOSITION = i32;
pub const EXCEPTION_ROUTINE = *const fn (
ExceptionRecord: ?*EXCEPTION_RECORD,
EstablisherFrame: PVOID,
ContextRecord: *(Self.CONTEXT),
DispatcherContext: PVOID,
) callconv(WINAPI) EXCEPTION_DISPOSITION;

pub const UNWIND_HISTORY_TABLE_SIZE = 12;
pub const UNWIND_HISTORY_TABLE_ENTRY = extern struct {
ImageBase: ULONG64,
FunctionEntry: *Self.RUNTIME_FUNCTION,
};

pub const UNWIND_HISTORY_TABLE = extern struct {
Count: ULONG,
LocalHint: BYTE,
GlobalHint: BYTE,
Search: BYTE,
Once: BYTE,
LowAddress: ULONG64,
HighAddress: ULONG64,
Entry: [UNWIND_HISTORY_TABLE_SIZE]UNWIND_HISTORY_TABLE_ENTRY,
};

pub const UNW_FLAG_NHANDLER = 0x0;
pub const UNW_FLAG_EHANDLER = 0x1;
pub const UNW_FLAG_UHANDLER = 0x2;
pub const UNW_FLAG_CHAININFO = 0x4;

pub const OBJECT_ATTRIBUTES = extern struct {
Length: ULONG,
RootDirectory: ?HANDLE,
Expand Down Expand Up @@ -3494,6 +3593,21 @@ pub const TEB = extern struct {
TlsExpansionSlots: PVOID,
};

pub const EXCEPTION_REGISTRATION_RECORD = extern struct {
Next: ?*EXCEPTION_REGISTRATION_RECORD,
Handler: ?*EXCEPTION_DISPOSITION,
};

pub const NT_TIB = extern struct {
ExceptionList: ?*EXCEPTION_REGISTRATION_RECORD,
StackBase: PVOID,
StackLimit: PVOID,
SubSystemTib: PVOID,
DUMMYUNIONNAME: extern union { FiberData: PVOID, Version: DWORD },
ArbitraryUserPointer: PVOID,
Self: ?*@This(),
};

/// Process Environment Block
/// Microsoft documentation of this is incomplete, the fields here are taken from various resources including:
/// - https://github.com/wine-mirror/wine/blob/1aff1e6a370ee8c0213a0fd4b220d121da8527aa/include/winternl.h#L269
Expand Down
25 changes: 25 additions & 0 deletions lib/std/os/windows/kernel32.zig
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Original file line number Diff line number Diff line change
Expand Up @@ -5,8 +5,10 @@ const BOOL = windows.BOOL;
const BOOLEAN = windows.BOOLEAN;
const CONDITION_VARIABLE = windows.CONDITION_VARIABLE;
const CONSOLE_SCREEN_BUFFER_INFO = windows.CONSOLE_SCREEN_BUFFER_INFO;
const CONTEXT = windows.CONTEXT;
const COORD = windows.COORD;
const DWORD = windows.DWORD;
const DWORD64 = windows.DWORD64;
const FILE_INFO_BY_HANDLE_CLASS = windows.FILE_INFO_BY_HANDLE_CLASS;
const HANDLE = windows.HANDLE;
const HMODULE = windows.HMODULE;
Expand Down Expand Up @@ -60,6 +62,10 @@ const INIT_ONCE_FN = windows.INIT_ONCE_FN;
const PMEMORY_BASIC_INFORMATION = windows.PMEMORY_BASIC_INFORMATION;
const REGSAM = windows.REGSAM;
const LSTATUS = windows.LSTATUS;
const UNWIND_HISTORY_TABLE = windows.UNWIND_HISTORY_TABLE;
const RUNTIME_FUNCTION = windows.RUNTIME_FUNCTION;
const KNONVOLATILE_CONTEXT_POINTERS = windows.KNONVOLATILE_CONTEXT_POINTERS;
const EXCEPTION_ROUTINE = windows.EXCEPTION_ROUTINE;

pub extern "kernel32" fn AddVectoredExceptionHandler(First: c_ulong, Handler: ?VECTORED_EXCEPTION_HANDLER) callconv(WINAPI) ?*anyopaque;
pub extern "kernel32" fn RemoveVectoredExceptionHandler(Handle: HANDLE) callconv(WINAPI) c_ulong;
Expand Down Expand Up @@ -292,6 +298,25 @@ pub extern "kernel32" fn ReadFile(

pub extern "kernel32" fn RemoveDirectoryW(lpPathName: [*:0]const u16) callconv(WINAPI) BOOL;

pub extern "kernel32" fn RtlCaptureContext(ContextRecord: *CONTEXT) callconv(WINAPI) void;

pub extern "kernel32" fn RtlLookupFunctionEntry(
ControlPc: DWORD64,
ImageBase: *DWORD64,
HistoryTable: *UNWIND_HISTORY_TABLE,
) callconv(WINAPI) ?*RUNTIME_FUNCTION;

pub extern "kernel32" fn RtlVirtualUnwind(
HandlerType: DWORD,
ImageBase: DWORD64,
ControlPc: DWORD64,
FunctionEntry: *RUNTIME_FUNCTION,
ContextRecord: *CONTEXT,
HandlerData: *?PVOID,
EstablisherFrame: *DWORD64,
ContextPointers: ?*KNONVOLATILE_CONTEXT_POINTERS,
) callconv(WINAPI) *EXCEPTION_ROUTINE;

pub extern "kernel32" fn SetConsoleTextAttribute(hConsoleOutput: HANDLE, wAttributes: WORD) callconv(WINAPI) BOOL;

pub extern "kernel32" fn SetConsoleCtrlHandler(
Expand Down
22 changes: 22 additions & 0 deletions lib/std/os/windows/ntdll.zig
View file
Original file line number Diff line number Diff line change
Expand Up @@ -3,6 +3,7 @@ const windows = std.os.windows;

const BOOL = windows.BOOL;
const DWORD = windows.DWORD;
const DWORD64 = windows.DWORD64;
const ULONG = windows.ULONG;
const WINAPI = windows.WINAPI;
const NTSTATUS = windows.NTSTATUS;
Expand All @@ -24,6 +25,11 @@ const SIZE_T = windows.SIZE_T;
const CURDIR = windows.CURDIR;
const PCWSTR = windows.PCWSTR;
const RTL_QUERY_REGISTRY_TABLE = windows.RTL_QUERY_REGISTRY_TABLE;
const CONTEXT = windows.CONTEXT;
const UNWIND_HISTORY_TABLE = windows.UNWIND_HISTORY_TABLE;
const RUNTIME_FUNCTION = windows.RUNTIME_FUNCTION;
const KNONVOLATILE_CONTEXT_POINTERS = windows.KNONVOLATILE_CONTEXT_POINTERS;
const EXCEPTION_ROUTINE = windows.EXCEPTION_ROUTINE;

pub const THREADINFOCLASS = enum(c_int) {
ThreadBasicInformation,
Expand Down Expand Up @@ -99,6 +105,22 @@ pub extern "ntdll" fn RtlCaptureStackBackTrace(
BackTrace: **anyopaque,
BackTraceHash: ?*DWORD,
) callconv(WINAPI) WORD;
pub extern "ntdll" fn RtlCaptureContext(ContextRecord: *CONTEXT) callconv(WINAPI) void;
pub extern "ntdll" fn RtlLookupFunctionEntry(
ControlPc: DWORD64,
ImageBase: *DWORD64,
HistoryTable: *UNWIND_HISTORY_TABLE,
) callconv(WINAPI) ?*RUNTIME_FUNCTION;
pub extern "ntdll" fn RtlVirtualUnwind(
HandlerType: DWORD,
ImageBase: DWORD64,
ControlPc: DWORD64,
FunctionEntry: *RUNTIME_FUNCTION,
ContextRecord: *CONTEXT,
HandlerData: *?PVOID,
EstablisherFrame: *DWORD64,
ContextPointers: ?*KNONVOLATILE_CONTEXT_POINTERS,
) callconv(WINAPI) *EXCEPTION_ROUTINE;
pub extern "ntdll" fn NtQueryInformationFile(
FileHandle: HANDLE,
IoStatusBlock: *IO_STATUS_BLOCK,
Expand Down

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