Move most of codegen into basm-std

Author: byeongkeunahn

basm-std/Cargo.toml

@@ -25,4 +25,8 @@ compiler_builtins = { version = "0.1.103", features = ["mem"] }
 compiler_builtins = { version = "0.1.103", features = ["mem"] }
 
 [features]
+# Enables codegen routines.
+# When this feature is enabled, the external implementations should provide an `extern "C" fn _basm_main()`.
+codegen = []
+# Favors short routines for code golf.
 short = []

basm/src/bin/codegen.rs renamed to basm-std/src/platform/codegen.rs

@@ -1,16 +1,9 @@
-#![cfg(not(test))]
-
 #[cfg(not(target_arch = "wasm32"))]
 use core::arch::asm;
 
-use crate::solution;
-use basm::platform;
-use basm::platform::allocator;
+use crate::platform;
 #[cfg(not(target_arch = "wasm32"))]
-use basm::platform::loader;
-
-#[global_allocator]
-static ALLOC: allocator::Allocator = allocator::Allocator;
+use crate::platform::loader;
 
 /* We need to support multiple scenarios.
  *   1) Architectures: x86, x86-64
@@ -28,9 +21,9 @@ static ALLOC: allocator::Allocator = allocator::Allocator;
  * For 4), we build the binary to run without the loader.
  *   When running without the loader, the binary will fabricate a dummy
  *     SERVICE_FUNCTIONS and PLATFORM_DATA table at the beginning of the
- *     EntryPoint (_start).
+ *     EntryPoint (_basm_start).
  *   When running with the loader, the loader patches the beginning of
- *     the EntryPoint (_start) to override the platform configuration data.
+ *     the EntryPoint (_basm_start) to override the platform configuration data.
  *
  * When running without the loader, the relocations are handled differently.
  *   For Windows, the Windows kernel will handle relocations for us,
@@ -54,7 +47,7 @@ compile_error!("The target architecture is not supported.");
 #[cfg(all(target_arch = "x86_64", not(target_os = "windows")))]
 #[no_mangle]
 #[naked]
-unsafe extern "win64" fn _start() -> ! {
+pub unsafe extern "win64" fn _basm_start() -> ! {
     // AMD64 System V ABI requires RSP to be aligned
     //   on the 16-byte boundary BEFORE `call` instruction.
     // However, when called as the entrypoint by the Linux OS,
@@ -103,7 +96,7 @@ unsafe extern "sysv64" fn get_kernel32() -> usize {
 #[cfg(all(target_arch = "x86_64", target_os = "windows"))]
 #[no_mangle]
 #[naked]
-unsafe extern "win64" fn _start() -> ! {
+pub unsafe extern "win64" fn _basm_start() -> ! {
     // Microsoft x64 ABI requires RSP to be aligned
     //   on the 16-byte boundary BEFORE `call` instruction.
     // Also, when called as the entrypoint by the Windows OS,
@@ -162,7 +155,7 @@ unsafe extern "win64" fn _start() -> ! {
 #[link_section = ".data"]
 unsafe extern "cdecl" fn _get_start_offset() -> ! {
     asm!(
-        "lea    eax, [_start]",
+        "lea    eax, [_basm_start]",
         "ret",
         options(noreturn)
     );
@@ -183,7 +176,7 @@ unsafe extern "cdecl" fn _get_dynamic_section_offset() -> ! {
 #[cfg(target_arch = "x86")]
 #[no_mangle]
 #[naked]
-unsafe extern "cdecl" fn _start() -> ! {
+pub unsafe extern "cdecl" fn _basm_start() -> ! {
     // i386 System V ABI requires ESP to be aligned
     //   on the 16-byte boundary BEFORE `call` instruction
     asm!(
@@ -205,9 +198,9 @@ unsafe extern "cdecl" fn _start() -> ! {
         "2:",
         "call   3f",
         "3:",
-        "pop    ecx",                       // ecx = _start + 36 (obtained by counting the opcode size in bytes)
+        "pop    ecx",                       // ecx = _basm_start + 36 (obtained by counting the opcode size in bytes)
         "push   edx",                       // [esp + 0] = PLATFORM_DATA table
-        "call   {2}",                       // eax = offset of _start from the image base
+        "call   {2}",                       // eax = offset of _basm_start from the image base
         "sub    ecx, eax",
         "sub    ecx, 36",                   // ecx = the in-memory image base (i.e., __ehdr_start)
         "call   {3}",                       // eax = offset of _DYNAMIC table from the image base
@@ -231,7 +224,7 @@ unsafe extern "cdecl" fn _start() -> ! {
 
 #[cfg(target_arch = "wasm32")]
 #[no_mangle]
-extern "C" fn _start() {
+pub extern "C" fn _basm_start() {
     let mut pd = platform::services::PlatformData {
         env_id: platform::services::ENV_ID_WASM,
         .. Default::default()
@@ -246,7 +239,10 @@ extern "C" fn _start() {
  */
 #[cfg_attr(not(feature = "short"), inline(never))]
 fn _call_main() {
-    solution::main();
+    extern "C" {
+        fn _basm_main();
+    }
+    unsafe { _basm_main() }
 }
 fn _start_rust(platform_data: usize) -> i32 {
     platform::init(platform_data);
@@ -259,7 +255,7 @@ fn _start_rust(platform_data: usize) -> i32 {
 #[naked]
 #[repr(align(4))]
 #[cfg(all(target_arch = "x86_64", target_os = "windows"))]
-unsafe extern "win64" fn __chkstk() -> ! {
+pub unsafe extern "win64" fn __chkstk() -> ! {
     asm!(
         "push   rcx",
         "push   rax",
@@ -280,30 +276,4 @@ unsafe extern "win64" fn __chkstk() -> ! {
         "ret",
         options(noreturn)
     );
-}
-
-#[no_mangle]
-#[cfg(target_os = "windows")]
-static mut _fltused: i32 = 0;
-
-#[no_mangle]
-#[cfg(target_os = "windows")]
-extern "win64" fn __CxxFrameHandler3() -> ! {
-    unsafe { core::hint::unreachable_unchecked() }
-}
-
-#[alloc_error_handler]
-fn alloc_fail(_: core::alloc::Layout) -> ! {
-    unsafe { core::hint::unreachable_unchecked() }
-}
-
-#[no_mangle]
-#[allow(non_snake_case)]
-pub fn _Unwind_Resume() {
-    unsafe { core::hint::unreachable_unchecked() }
-}
-
-#[no_mangle]
-pub fn rust_eh_personality() {
-    unsafe { core::hint::unreachable_unchecked() }
-}
+}

basm-std/src/platform/mod.rs

@@ -1,3 +1,5 @@
+#[cfg(all(not(test), feature = "codegen"))]
+pub mod codegen;
 #[cfg(not(test))]
 pub mod loader;
 #[cfg(not(test))]

basm/Cargo.toml

@@ -21,12 +21,13 @@ name = "basm-submit"
 test = false
 bench = false
 path = "src/bin/basm-submit.rs"
+required-features = ["submit"]
 
 [dependencies]
 libm = "0.2.7"
 ryu = "1.0"
-basm-std = { path = "../basm-std" }
 basm-macro = { path = "../basm-macro" }
+basm-std = { path = "../basm-std", features = ["codegen"] }
 
 [target.x86_64-pc-windows-msvc.dependencies]
 compiler_builtins = { version = "0.1.103", features = ["mem"] }
@@ -39,3 +40,4 @@ compiler_builtins = { version = "0.1.103", features = ["mem"] }
 
 [features]
 short = []
+submit = []

basm/build.rs

@@ -11,7 +11,7 @@ fn main() {
             link_args_basm.push("/SUBSYSTEM:CONSOLE");
             link_args_basm.push("/NODEFAULTLIB");
             link_args_basm.push("/DYNAMICBASE");
-            link_args_basm.push("/ENTRY:_start");
+            link_args_basm.push("/ENTRY:_basm_start");
             link_args_basm.push("/NXCOMPAT:NO");
             link_args_basm.push("/STACK:268435456");
             link_args_basm.push("/EMITTOOLVERSIONINFO:NO");
@@ -30,9 +30,9 @@ fn main() {
             if target == "i686-unknown-linux-gnu" {
                 // Prevent linker from putting data into text, which is non-writable and hence not relocatable.
                 // This prevents the hack for getting the _DYNAMIC symbol in the entrypoint.
-                link_args_basm.push("-Wl,--build-id=none,--gc-sections,--export-dynamic,--no-eh-frame-hdr,-z,norelro,-z,notext");
+                link_args_basm.push("-Wl,--entry=_basm_start,--build-id=none,--gc-sections,--export-dynamic,--no-eh-frame-hdr,-z,norelro,-z,notext");
             } else {
-                link_args_basm.push("-Wl,--build-id=none,--gc-sections,--export-dynamic,--no-eh-frame-hdr,-z,norelro");
+                link_args_basm.push("-Wl,--entry=_basm_start,--build-id=none,--gc-sections,--export-dynamic,--no-eh-frame-hdr,-z,norelro");
             }
             link_args_basm_submit.push("-Wl,-z,max-page-size=128");
         },

basm/src/bin/basm-lib.rs

@@ -7,11 +7,12 @@
 #![cfg_attr(not(test), no_builtins)]
 #![cfg_attr(not(test), no_std)]
 #![cfg_attr(not(test), no_main)]
-extern crate alloc;
 
+extern crate alloc;
 extern crate basm_std as basm;
+mod lang_items;
 
-#[allow(dead_code)]
+#[cfg_attr(test, allow(dead_code))]
 #[path = "../solution.rs"]
 mod solution;
 

basm/src/bin/basm-submit.rs

@@ -7,17 +7,11 @@
 #![cfg_attr(not(test), no_builtins)]
 #![cfg_attr(not(test), no_std)]
 #![cfg_attr(not(test), no_main)]
-extern crate alloc;
 
+extern crate alloc;
 extern crate basm_std as basm;
+mod lang_items;
 
 #[cfg_attr(test, allow(dead_code))]
 #[path = "../solution.rs"]
-mod solution;
-mod codegen;
-
-#[cfg(not(test))]
-#[panic_handler]
-fn panic(_pi: &core::panic::PanicInfo) -> ! {
-    unsafe { core::hint::unreachable_unchecked() }
-}
+mod solution;

basm/src/bin/basm.rs

@@ -7,36 +7,11 @@
 #![cfg_attr(not(test), no_builtins)]
 #![cfg_attr(not(test), no_std)]
 #![cfg_attr(not(test), no_main)]
-extern crate alloc;
 
+extern crate alloc;
 extern crate basm_std as basm;
+mod lang_items;
 
 #[cfg_attr(test, allow(dead_code))]
 #[path = "../solution.rs"]
-mod solution;
-mod codegen;
-
-#[cfg(not(test))]
-#[panic_handler]
-fn panic(_pi: &core::panic::PanicInfo) -> ! {
-    use alloc::string::ToString;
-    use basm::platform::services::write_stdio;
-    write_stdio(2, _pi.to_string().as_bytes());
-    write_stdio(2, b"\n");
-
-    // Rust sets an exit code of 101 when the process panicked.
-    // Hence, we follow that practice for maximum compatibility.
-    // Reference: https://rust-cli.github.io/book/in-depth/exit-code.html
-    #[cfg(all(windows, target_arch = "x86_64"))]
-    {
-        extern "win64" {
-            fn ExitProcess(uExitCode: u32) -> !;
-        }
-        unsafe { ExitProcess(101); }
-    }
-    #[cfg(target_os = "linux")] {
-        unsafe { basm::platform::os::linux::syscall::exit_group(101); }
-    }
-    #[cfg(not(any(all(windows, target_arch = "x86_64"), target_os = "linux")))]
-    unsafe { core::hint::unreachable_unchecked() }
-}
+mod solution;

basm/src/bin/lang_items.rs

@@ -0,0 +1,67 @@
+#[no_mangle]
+extern "C" fn _basm_main() {
+    crate::solution::main()
+}
+
+#[cfg(not(test))]
+mod runtime {
+    #[global_allocator]
+    static ALLOC: basm::platform::allocator::Allocator = basm::platform::allocator::Allocator;
+
+    #[no_mangle]
+    #[cfg(target_os = "windows")]
+    static mut _fltused: i32 = 0;
+
+    #[no_mangle]
+    #[cfg(target_os = "windows")]
+    extern "win64" fn __CxxFrameHandler3() -> ! {
+        unsafe { core::hint::unreachable_unchecked() }
+    }
+
+    #[alloc_error_handler]
+    fn alloc_fail(_: core::alloc::Layout) -> ! {
+        unsafe { core::hint::unreachable_unchecked() }
+    }
+
+    #[no_mangle]
+    #[allow(non_snake_case)]
+    fn _Unwind_Resume() {
+        unsafe { core::hint::unreachable_unchecked() }
+    }
+
+    #[no_mangle]
+    fn rust_eh_personality() {
+        unsafe { core::hint::unreachable_unchecked() }
+    }
+
+    #[cfg(all(not(test), feature = "submit"))]
+    #[panic_handler]
+    fn panic(_pi: &core::panic::PanicInfo) -> ! {
+        unsafe { core::hint::unreachable_unchecked() }
+    }
+
+    #[cfg(all(not(test), not(feature = "submit")))]
+    #[panic_handler]
+    fn panic(_pi: &core::panic::PanicInfo) -> ! {
+        use alloc::string::ToString;
+        use basm::platform::services::write_stdio;
+        write_stdio(2, _pi.to_string().as_bytes());
+        write_stdio(2, b"\n");
+
+        // Rust sets an exit code of 101 when the process panicked.
+        // Hence, we follow that practice for maximum compatibility.
+        // Reference: https://rust-cli.github.io/book/in-depth/exit-code.html
+        #[cfg(all(windows, target_arch = "x86_64"))]
+        {
+            extern "win64" {
+                fn ExitProcess(uExitCode: u32) -> !;
+            }
+            unsafe { ExitProcess(101); }
+        }
+        #[cfg(target_os = "linux")] {
+            unsafe { basm::platform::os::linux::syscall::exit_group(101); }
+        }
+        #[cfg(not(any(all(windows, target_arch = "x86_64"), target_os = "linux")))]
+        unsafe { core::hint::unreachable_unchecked() }
+    }
+}

release-64bit-windows-fn-impl.cmd

@@ -1,5 +1,5 @@
 @echo off
-cargo +nightly build --target x86_64-pc-windows-msvc --bin basm-submit --release || goto :error
+cargo +nightly build --target x86_64-pc-windows-msvc --bin basm-submit --features=submit --release || goto :error
 python scripts/static-pie-gen.py basm/src/solution.rs x86_64-pc-windows-msvc target/x86_64-pc-windows-msvc/release/basm-submit.exe static-pie-stub-amd64.bin C static-pie-template-amd64-fn-impl.c || goto :error
 
 :; exit 0