drop gcc by default, any type

.gitignore

@@ -1,5 +1,4 @@
 /target
 /out*
 /TODO
-/musl-*
 /vscode

README.md

@@ -6,9 +6,8 @@ A very cool language
 * Clean indentation-based syntax
 * Compiles to x86_64 Assembly
 * Growing [standard library](https://github.com/antpiasecki/zern/tree/main/src/std)
-* Produces tiny static executables (~30KB with musl)
+* Produces tiny static executables (11KB for `hello.zr`)
 * No libc required!
-* Sometimes works
 * Has the pipe operator
 
 ## Syntax

src/codegen_x86_64.rs

@@ -70,7 +70,7 @@ macro_rules! emit {
 static REGISTERS: [&str; 6] = ["rdi", "rsi", "rdx", "rcx", "r8", "r9"];
 
 // TODO: currently they are all just 64 bit values
-static BUILTIN_TYPES: [&str; 6] = ["void", "u8", "i64", "str", "bool", "ptr"];
+static BUILTIN_TYPES: [&str; 7] = ["void", "u8", "i64", "str", "bool", "ptr", "any"];
 
 pub struct CodegenX86_64<'a> {
     output: String,
@@ -100,7 +100,7 @@ impl<'a> CodegenX86_64<'a> {
         format!("section .data\n{}{}", self.data_section, self.output)
     }
 
-    pub fn emit_prologue(&mut self) -> Result<(), ZernError> {
+    pub fn emit_prologue(&mut self, emit_start: bool) -> Result<(), ZernError> {
         emit!(
             &mut self.output,
             "section .note.GNU-stack
@@ -109,6 +109,7 @@ impl<'a> CodegenX86_64<'a> {
 section .bss
     _heap_head: resq 1
     _heap_tail: resq 1
+    _environ: resq 1
 
 section .text._builtin_heap_head
 _builtin_heap_head:
@@ -141,14 +142,52 @@ _builtin_syscall:
     mov r9,  [rsp+8]
     syscall
     ret
+"
+        );
 
+        if emit_start {
+            emit!(
+                &mut self.output,
+                "
+section .text._builtin_environ
+_builtin_environ:
+    lea     rax, [rel _environ]
+    mov     rax, [rax]
+    ret
+
+global _start
+section .text
+_start:
+    xor     rbp, rbp
+    ; setup args
+    pop     rdi
+    mov     rsi, rsp
+    ; save environ
+    lea     rdx, [rsi + rdi*8 + 8]
+    lea     rax, [rel _environ]
+    mov     [rax], rdx
+    ; align stack
+    and     rsp, -16
+    ; main()
+    call    main
+    ; exit
+    mov     rdi, rax
+    mov     rax, 60
+    syscall
+"
+            );
+        } else {
+            emit!(
+                &mut self.output,
+                "
 section .text._builtin_environ
 _builtin_environ:
     extern environ
     mov rax, [rel environ]
     ret
 "
-        );
+            );
+        }
         Ok(())
     }
 

src/main.rs

@@ -63,7 +63,7 @@ fn compile_file(args: Args) -> Result<(), ZernError> {
 
     let mut analyzer = analyzer::Analyzer::new();
     let mut codegen = codegen_x86_64::CodegenX86_64::new(&mut analyzer);
-    codegen.emit_prologue()?;
+    codegen.emit_prologue(!args.use_gcc)?;
     compile_file_to(
         &mut codegen,
         "syscalls.zr",
@@ -82,15 +82,15 @@ fn compile_file(args: Args) -> Result<(), ZernError> {
 
         run_command(format!("nasm -f elf64 -o {}.o {}.s", args.out, args.out));
 
-        if args.use_glibc {
+        if args.use_gcc {
             run_command(format!(
                 "gcc -no-pie -o {} {}.o -flto -Wl,--gc-sections {}",
                 args.out, args.out, args.cflags
             ));
         } else {
             run_command(format!(
-                "musl-gcc -static -o {} {}.o -flto -Wl,--gc-sections {}",
-                args.out, args.out, args.cflags
+                "ld -static -o {} {}.o --gc-sections -e _start",
+                args.out, args.out
             ));
         }
 
@@ -123,8 +123,8 @@ struct Args {
     #[arg(short = 'r', help = "Run the compiled executable")]
     run_exe: bool,
 
-    #[arg(short = 'm', help = "Use glibc instead of musl")]
-    use_glibc: bool,
+    #[arg(short = 'm', help = "Use gcc")]
+    use_gcc: bool,
 
     #[arg(short = 'C', default_value = "", help = "Extra flags to pass to gcc")]
     cflags: String,

src/std/std.zr

@@ -28,13 +28,17 @@ func mem._split_block[blk: mem.Block, needed: i64] : void
             mem.write64(_builtin_heap_tail(), new_blk)
 
 func mem._request_space[size: i64] : mem.Block
-    let blk: mem.Block = _builtin_syscall(SYS_brk, 0)
-    let new_brk: ptr = blk + MEM_BLOCK_SIZE + size
-    let result: ptr = _builtin_syscall(SYS_brk, new_brk)
-    if result != new_brk
+    let needed: i64 = size + MEM_BLOCK_SIZE
+    let alloc_size: i64 = (needed + 4095) & -4096
+
+    // PROT_READ | PROT_WRITE = 3
+    // MAP_PRIVATE | MAP_ANONYMOUS = 34
+    // fd = -1, offset = 0
+    let blk: mem.Block = _builtin_syscall(SYS_mmap, 0, alloc_size, 3, 34, -1, 0)
+    if blk == -1
         return 0
 
-    blk->size = size
+    blk->size = alloc_size - MEM_BLOCK_SIZE
     blk->free = false
     blk->next = 0
 
@@ -47,15 +51,36 @@ func mem._request_space[size: i64] : mem.Block
 
 func mem._coalesce[] : void
     let cur: mem.Block = mem.read64(_builtin_heap_head())
-    while cur && cur->next
+    let prev: mem.Block = 0
+    
+    while cur
         let next: mem.Block = cur->next
-        if cur->free && next->free
+        let expected_next: mem.Block = cur + MEM_BLOCK_SIZE + cur->size
+        
+        if cur->free && next && next->free && expected_next == next
             cur->size = cur->size + MEM_BLOCK_SIZE + next->size
             cur->next = next->next
             if !cur->next
                 mem.write64(_builtin_heap_tail(), cur)
-        else
+            continue
+            
+        let block_total: i64 = cur->size + MEM_BLOCK_SIZE
+        if cur->free && (cur & 4095) == 0 && (block_total & 4095) == 0
+            if prev
+                prev->next = cur->next
+                if !cur->next
+                    mem.write64(_builtin_heap_tail(), prev)
+            else
+                mem.write64(_builtin_heap_head(), cur->next)
+                if !cur->next
+                    mem.write64(_builtin_heap_tail(), 0)
+            
+            _builtin_syscall(SYS_munmap, cur, block_total)
             cur = cur->next
+            continue
+            
+        prev = cur
+        cur = cur->next
 
 func mem.alloc[size: i64] : ptr
     if size == 0
@@ -78,6 +103,8 @@ func mem.alloc[size: i64] : ptr
     if !mem.read64(_builtin_heap_head())
         mem.write64(_builtin_heap_head(), blk)
     
+    mem._split_block(blk, size)
+    
     return blk + MEM_BLOCK_SIZE
 
 func mem.free[x: ptr] : void
@@ -104,7 +131,9 @@ func mem.realloc[x: ptr, new_size: i64] : ptr
         return x
 
     let next: mem.Block = blk->next
-    if next && next->free
+    let expected_next: mem.Block = blk + MEM_BLOCK_SIZE + blk->size
+    
+    if next && next->free && expected_next == next
         let combined: i64 = blk->size + MEM_BLOCK_SIZE + next->size
         if combined >= new_size
             blk->size = combined
@@ -199,7 +228,7 @@ func io.read_line[]: str
 func io.read_file[path: str] : str
     let fd: i64 = _builtin_syscall(SYS_openat, -100, path, 0, 0)
     if fd <= 0
-        panic("failed to open file")
+        panic("failed to open file") // TODO
 
     let size: i64 = _builtin_syscall(SYS_lseek, fd, 0, 2)
     _builtin_syscall(SYS_lseek, fd, 0, 0)
@@ -217,7 +246,7 @@ struct io.Buffer
 func io.read_binary_file[path: str] : io.Buffer
     let fd: i64 = _builtin_syscall(SYS_openat, -100, path, 0, 0)
     if fd < 0
-        panic("failed to open file")
+        panic("failed to open file") // TODO
     
     let buffer: io.Buffer = new io.Buffer
     buffer->size = _builtin_syscall(SYS_lseek, fd, 0, 2)
@@ -231,7 +260,7 @@ func io.read_binary_file[path: str] : io.Buffer
 func io.write_file[path: str, content: str] : void
     let fd: ptr = _builtin_syscall(SYS_openat, -100, path, 0x241, 0o644)
     if fd < 0
-        panic("failed to open file")
+        panic("failed to open file") // TODO
 
     _builtin_syscall(SYS_write, fd, content, str.len(content))
     _builtin_syscall(SYS_close, fd)
@@ -373,7 +402,7 @@ func str.reverse[s: str] : str
     out[len] = 0
     return out
 
-// not sure this covers all wacky edge cases
+// not sure this covers all the wacky edge cases
 func str.from_i64[n: i64] : str
     if n == 0
         return str.copy("0")
@@ -559,17 +588,17 @@ struct Array
 func array.new[] : Array
     return new Array
 
-func array.nth[xs: Array, n: i64] : i64
+func array.nth[xs: Array, n: i64] : any
     if n < 0 || n >= xs->size
         panic("array.nth out of bounds")
     return mem.read64(xs->data + n * 8)
 
-func array.set[xs: Array, n: i64, x: i64] : void
+func array.set[xs: Array, n: i64, x: any] : void
     if n < 0 || n >= xs->size
         panic("array.set out of bounds")
     mem.write64(xs->data + n * 8, x)
 
-func array.push[xs: Array, x: i64] : void
+func array.push[xs: Array, x: any] : void
     if xs->size == xs->capacity
         let new_capacity = 4
         if xs->capacity != 0
@@ -585,10 +614,10 @@ func array.free[xs: Array] : void
         mem.free(xs->data)
     mem.free(xs)
 
-func array.pop[xs: Array] : i64
+func array.pop[xs: Array] : any
     if xs->size == 0
         panic("array.pop on empty array")
-    let x: i64 = array.nth(xs, xs->size - 1)
+    let x: any = array.nth(xs, xs->size - 1)
     xs->size = xs->size - 1
     return x
 
@@ -632,7 +661,7 @@ func alg._partition[arr: Array, low: i64, high: i64] : i64
     array.set(arr, high, temp)
     return i + 1
 
-func alg.count[arr: Array, item: i64] : i64
+func alg.count[arr: Array, item: any] : i64
     let count = 0
     for i in 0..arr->size
         if array.nth(arr, i) == item
@@ -652,7 +681,7 @@ func alg.filter[arr: Array, fn: ptr] : Array
             array.push(out, array.nth(arr, i))
     return out
 
-func alg.reduce[arr: Array, fn: ptr, acc: i64] : i64
+func alg.reduce[arr: Array, fn: ptr, acc: any] : any
     for i in 0..arr->size
         acc = fn(acc, array.nth(arr, i))
     return acc
@@ -680,15 +709,15 @@ struct os.Timeval
 func os.time[] : i64
     let tv: os.Timeval = new os.Timeval
     _builtin_syscall(SYS_gettimeofday, tv, 0)
+    let out: i64 = tv->tv_sec * 1000 + tv->tv_usec / 1000
     mem.free(tv)
-    return tv->tv_sec * 1000 + tv->tv_usec / 1000
+    return out
 
 // voodoo magic
 func os.shell[command: str] : i64
     let pid: i64 = _builtin_syscall(SYS_fork)
     if pid == 0
-        // leaky but not sure where can i free it
-        let argv: Array = ["sh", "-c", command, 0]
+        let argv: Array = ["sh", "-c", command, 0] // gets freed after child process exits
         _builtin_syscall(SYS_execve, "/bin/sh", argv->data, _builtin_environ())
         _builtin_syscall(SYS_exit, 1)
     else
@@ -770,6 +799,7 @@ func net.listen[packed_host: i64, port: i64] : i64
     
     return s
 
+// TODO: resolve DNS
 func net.connect[packed_host: i64, port: i64] : i64
     let s: i64 = _builtin_syscall(SYS_socket, 2, 1, 0)
     if s < 0