LLVM broken module with heavy comptime stuff

[davidgmbb]

Zig Version

0.11.0-dev.3258+7621e5693

Steps to Reproduce and Observed Behavior

git clone https://github.com/davidgm94/rise.git
cd rise
git switch llvm-broken-module
zig build

The executable where it crashes is not that big, so maybe a developer can find the error easily :)
Crash log: https://gist.github.com/davidgm94/9831296ec0948125460957f0526919e5

Expected Behavior

A compile error or a successful compiler run, not a crash.

[davidgmbb]

This is one of the main suspects. Even then if I replace the return with a panic, main function still fails to verify with LLVM with a "no terminator found". Be aware that this is a freestanding compile and Zig is not providing the start code, I am (see _start in src/user/arch/x86_64.zig).

pub fn syscall(comptime capability_type: capabilities.Type, comptime capability_command: @field(capabilities, @tagName(capability_type)), arguments: capabilities.Arguments(capability_type, capability_command)) capabilities.ErrorSet(capability_type, capability_command).Error!capabilities.Result(capability_type, capability_command) {
    const options = rise.syscall.Options{
        .rise = .{
            .type = capability_type,
            .command = @enumToInt(capability_command),
        },
    };

    const raw_arguments: [6]usize = switch (@typeInfo(@TypeOf(arguments))) {
        .Pointer => |pointer| switch (pointer.size) {
            .Slice => .{0} ** 4 ++ [2]usize{ @ptrToInt(arguments.ptr), arguments.len },
            else => @compileError("Unexpected pointer type"),
        },
        .Void => .{0} ** 6,
        else => |_| @compileError("t: " ++ @typeName(@TypeOf(arguments))),
    };

    const result = arch.syscall(options, raw_arguments);
    const ThisErrorSet = capabilities.ErrorSet(capability_type, capability_command);
    const error_enum = @intToEnum(ThisErrorSet.Enum, result.rise.first.@"error");
    return switch (error_enum) {
        .ok => switch (capabilities.Result(capability_type, capability_command)) {
            noreturn => unreachable,
            else => while (true) {},
        },
        inline else => |comptime_error_enum| @field(ThisErrorSet.Error, @tagName(comptime_error_enum)),
    };
}

[Vexu]

Caused by #13807

You can work around this bug by ensuring that the error set always includes at least one error:

diff --git a/src/user.zig b/src/user.zig
index 9914c20..aa85f0e 100644
--- a/src/user.zig
+++ b/src/user.zig
@@ -77,13 +77,15 @@ pub const VirtualAddress = enum(usize) {
     }
 };
 
-pub fn syscall(comptime capability_type: capabilities.Type, comptime capability_command: @field(capabilities, @tagName(capability_type)), arguments: capabilities.Arguments(capability_type, capability_command)) capabilities.ErrorSet(capability_type, capability_command).Error!capabilities.Result(capability_type, capability_command) {
+pub fn syscall(comptime capability_type: capabilities.Type, comptime capability_command: @field(capabilities, @tagName(capability_type)), arguments: capabilities.Arguments(capability_type, capability_command)) (capabilities.ErrorSet(capability_type, capability_command).Error || error{IgnoreMe})!capabilities.Result(capability_type, capability_command) {
     const options = rise.syscall.Options{
         .rise = .{
             .type = capability_type,
             .command = @enumToInt(capability_command),
         },
     };
+    var a = false;
+    if (a) return error.IgnoreMe;
 
     const raw_arguments: [6]usize = switch (@typeInfo(@TypeOf(arguments))) {
         .Pointer => |pointer| switch (pointer.size) {
@@ -102,6 +104,6 @@ pub fn syscall(comptime capability_type: capabilities.Type, comptime capability_
             noreturn => unreachable,
             else => while (true) {},
         },
-        inline else => |comptime_error_enum| @field(ThisErrorSet.Error, @tagName(comptime_error_enum)),
+        inline else => @panic("TODO properly handle adding a dummy error"),
     };
 }

[davidgmbb]

Thank you Vexu, keep up the good work.

My problem was my error comptime-generated sets were empty, although that was not my intention. I fixed it following your advice. Thanks a lot again.