Add #![no_builtins]

See aya-rs/aya#698 for rationale.

docs/book/start/hello-xdp.md

@@ -24,11 +24,12 @@ The logic for this program is located in `xdp-hello-ebpf/src/main.rs` and curren
 
 1. `#![no_std]` is required since we cannot use the standard library.
 2. `#![no_main]` is required as we have no main function.
-3. The `#[panic_handler]` is required to keep the compiler happy, although it is never used since we cannot panic.
-4. This indicates that this function is an XDP program.
-5. Our main entry point defers to another function and performs error handling, returning `XDP_ABORTED`, which will drop the packet.
-6. Write a log entry every time a packet is received.
-7. This function returns a `Result` that permits all traffic.
+3. `#![no_builtins]` is required as we cannot use LLVM intrinsics.
+4. The `#[panic_handler]` is required to keep the compiler happy, although it is never used since we cannot panic.
+5. This indicates that this function is an XDP program.
+6. Our main entry point defers to another function and performs error handling, returning `XDP_ABORTED`, which will drop the packet.
+7. Write a log entry every time a packet is received.
+8. This function returns a `Result` that permits all traffic.
 
 Now we can compile this using `cargo xtask build-ebpf`.
 

examples/aya-tool/myapp-ebpf/src/main.rs

@@ -1,5 +1,6 @@
-#![no_std]
+#![no_builtins]
 #![no_main]
+#![no_std]
 
 #[allow(non_upper_case_globals)]
 #[allow(non_snake_case)]

examples/cgroup-skb-egress/cgroup-skb-egress-ebpf/src/main.rs

@@ -1,5 +1,6 @@
-#![no_std]
+#![no_builtins]
 #![no_main]
+#![no_std]
 
 use aya_bpf::{
     macros::{cgroup_skb, map},

examples/kprobetcp/kprobetcp-ebpf/src/main.rs

@@ -1,5 +1,6 @@
-#![no_std]
+#![no_builtins]
 #![no_main]
+#![no_std]
 
 #[allow(non_upper_case_globals)]
 #[allow(non_snake_case)]

examples/lsm-nice/lsm-nice-ebpf/src/main.rs

@@ -1,5 +1,6 @@
-#![no_std]
+#![no_builtins]
 #![no_main]
+#![no_std]
 
 use aya_bpf::{cty::c_int, macros::lsm, programs::LsmContext};
 use aya_log_ebpf::info;

examples/tc-egress/tc-egress-ebpf/src/main.rs

@@ -1,5 +1,6 @@
-#![no_std]
+#![no_builtins]
 #![no_main]
+#![no_std]
 
 use aya_bpf::{
     bindings::{TC_ACT_PIPE, TC_ACT_SHOT},

examples/xdp-drop/xdp-drop-ebpf/src/main.rs

@@ -1,5 +1,6 @@
-#![no_std]
+#![no_builtins]
 #![no_main]
+#![no_std]
 #![allow(nonstandard_style, dead_code)]
 
 use aya_bpf::{

examples/xdp-hello/xdp-hello-ebpf/src/main.rs

@@ -1,26 +1,27 @@
 #![no_std] // (1)
 #![no_main] // (2)
+#![no_builtins] // (3)
 
 use aya_bpf::{bindings::xdp_action, macros::xdp, programs::XdpContext};
 use aya_log_ebpf::info;
 
-#[xdp] // (4)
+#[xdp] // (5)
 pub fn xdp_hello(ctx: XdpContext) -> u32 {
-    // (5)
+    // (6)
     match unsafe { try_xdp_hello(ctx) } {
         Ok(ret) => ret,
         Err(_) => xdp_action::XDP_ABORTED,
     }
 }
 
 unsafe fn try_xdp_hello(ctx: XdpContext) -> Result<u32, u32> {
-    // (6)
-    info!(&ctx, "received a packet");
     // (7)
+    info!(&ctx, "received a packet");
+    // (8)
     Ok(xdp_action::XDP_PASS)
 }
 
-#[panic_handler] // (3)
+#[panic_handler] // (4)
 fn panic(_info: &core::panic::PanicInfo) -> ! {
     unsafe { core::hint::unreachable_unchecked() }
 }

examples/xdp-log/xdp-log-ebpf/src/main.rs

@@ -1,5 +1,6 @@
-#![no_std]
+#![no_builtins]
 #![no_main]
+#![no_std]
 
 use aya_bpf::{bindings::xdp_action, macros::xdp, programs::XdpContext};
 use aya_log_ebpf::info;