mirror of
https://github.com/ziglang/zig.git
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a32b5929cc
* introduce zigrt file. it contains only weak symbols so that multiple instances can be merged. it contains __zig_panic so that multiple .o files can call the same panic function. * remove `@setFnVisible` builtin and add @setGlobalLinkage builtin which is more powerful * add `@panic` builtin function. * fix collision of symbols with extern prototypes and internal function names * add stack protector safety when linking against libc. To add the safety mechanism without libc requires implementing Thread Local Storage. See #276
60 lines
1.6 KiB
Zig
60 lines
1.6 KiB
Zig
// This file is in a package which has the root source file exposed as "@root".
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// It is included in the compilation unit when exporting an executable.
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const root = @import("@root");
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const std = @import("std");
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const want_main_symbol = std.target.linking_libc;
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const want_start_symbol = !want_main_symbol;
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const exit = std.os.posix.exit;
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var argc: usize = undefined;
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var argv: &&u8 = undefined;
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export nakedcc fn _start() -> noreturn {
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@setGlobalLinkage(_start, if (want_start_symbol) GlobalLinkage.Strong else GlobalLinkage.Internal);
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if (!want_start_symbol) {
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unreachable;
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}
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switch (@compileVar("arch")) {
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Arch.x86_64 => {
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argc = asm("mov %[argc], [rsp]": [argc] "=r" (-> usize));
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argv = asm("lea %[argv], [rsp + 8h]": [argv] "=r" (-> &&u8));
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},
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Arch.i386 => {
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argc = asm("mov %[argc], [esp]": [argc] "=r" (-> usize));
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argv = asm("lea %[argv], [esp + 4h]": [argv] "=r" (-> &&u8));
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},
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else => @compileError("unsupported arch"),
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}
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callMainAndExit()
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}
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fn callMain() -> %void {
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const args = @alloca([]u8, argc);
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for (args) |_, i| {
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const ptr = argv[i];
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args[i] = ptr[0...std.cstr.len(ptr)];
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}
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return root.main(args);
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}
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fn callMainAndExit() -> noreturn {
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callMain() %% exit(1);
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exit(0);
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}
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export fn main(c_argc: i32, c_argv: &&u8) -> i32 {
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@setGlobalLinkage(main, if (want_main_symbol) GlobalLinkage.Strong else GlobalLinkage.Internal);
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if (!want_main_symbol) {
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unreachable;
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}
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argc = usize(c_argc);
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argv = c_argv;
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callMain() %% return 1;
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return 0;
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}
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