How to get zig build to dump disassembly

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1

I’d like to look at the generated machine code but not sure how to enable zig build to output disassembly. I’m working on Windows.

2

zig build-exe some.zig -femit-asm
it’s on linux but I believe should work on Windows too.

3

Thanks. I’m building a project with a build.zig, so I wonder if there’s an equivalent when using zig build?

4

Yes.

pub fn build(b: *std.build.Builder) void {

    const target = b.standardTargetOptions(.{});
    const mode = b.standardReleaseOptions();
    const exe = b.addExecutable("zf", "src/main.zig");
    exe.single_threaded = true;
    exe.emit_asm = .emit; // <<<<<<<<<<<<<<<
    exe.setTarget(target);
    exe.setBuildMode(mode);
    exe.install();
}
1 Like
5

It’s a tagged union defined in zig-0.10.1/lib/std/build.zig:

    pub const EmitOption = union(enum) {
        default: void,
        no_emit: void,
        emit: void,
        emit_to: []const u8,
6

Thanks! I set this to a library I’m building but I don’t know where the output goes. There’s no .s or .asm files anywhere after rebuilding. :slight_smile: I guess I’ll try on Linux, see if I can get it to work there first.

7

In my case it is in the root of the project:

$ ls -1
build.zig
src
zf.s  <<<<<<<<<<
zig-cache
zig-out
1 Like
8

Did you try

zig build-lib ... -femit-asm
zig build-obj ... -femit-asm

?

9

That worked for producing asm output for the library root source file. But looks like it doesn’t contain the other source files than the root.

10

btw, I asked similar question some time ago