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const std = @import("std");
pub fn build(b: *std.Build) void {
// Default to ReleaseSafe because Debug pulls Zig's
// UBSan runtime and other sanitization, which needs
// f128/SSE ops, which i don't provide.
const optimize = b.option(std.builtin.OptimizeMode, "optimize", "optimize mode") orelse .ReleaseSafe;
// The kernel must NOT touch SSE/MMX/AVX until it has
// enabled them itself, so I strip those features and
// let the compiler use a soft-float ABI.
// `code_model = .kernel` keeps relocations valid for
// the higher-half load address in boot/linker.ld.
//
// In other words. Going raw baby
var query: std.Target.Query = .{
.cpu_arch = .x86_64,
.os_tag = .freestanding,
.abi = .none,
};
const Feature = std.Target.x86.Feature;
query.cpu_features_sub.addFeature(@intFromEnum(Feature.mmx));
query.cpu_features_sub.addFeature(@intFromEnum(Feature.sse));
query.cpu_features_sub.addFeature(@intFromEnum(Feature.sse2));
query.cpu_features_sub.addFeature(@intFromEnum(Feature.avx));
query.cpu_features_sub.addFeature(@intFromEnum(Feature.avx2));
query.cpu_features_add.addFeature(@intFromEnum(Feature.soft_float));
const target = b.resolveTargetQuery(query);
const kernel = b.addExecutable(.{
.name = "revel",
.root_module = b.createModule(.{
.root_source_file = b.path("boot/boot.zig"),
.target = target,
.optimize = optimize,
.code_model = .kernel,
.red_zone = false,
.single_threaded = true,
.link_libc = false,
}),
});
kernel.entry = .{ .symbol_name = "_start" };
kernel.pie = false;
kernel.setLinkerScript(b.path("boot/linker.ld"));
// the big guns
const revo_dep = b.dependency("revo", .{ .target = target, .optimize = optimize });
const revo_mod = revo_dep.module("revo");
var visited: std.AutoHashMap(*std.Build.Module, void) = .init(b.allocator);
defer visited.deinit();
kernelize(revo_mod, &visited);
// the thin guns
const bridge_mod = b.createModule(.{
.root_source_file = b.path("bridge/bridge.zig"),
.target = target,
.optimize = optimize,
.code_model = .kernel,
.red_zone = false,
.single_threaded = true,
.link_libc = false,
});
bridge_mod.addImport("revo", revo_mod);
kernel.root_module.addImport("bridge", bridge_mod);
b.installArtifact(kernel);
}
// force a module and everything it imports to the kernel's codegen settings
fn kernelize(mod: *std.Build.Module, visited: *std.AutoHashMap(*std.Build.Module, void)) void {
if (visited.contains(mod)) return;
visited.put(mod, {}) catch @panic("OOM building module graph");
mod.code_model = .kernel;
mod.red_zone = false;
mod.single_threaded = true;
var it = mod.import_table.iterator();
while (it.next()) |entry| kernelize(entry.value_ptr.*, visited);
}
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