Using zig as a clang replacement

biosbob · January 27, 2025, 7:20pm

i want to use zig as a drop-in replacement for a clang cross-compiler with -t arm-none-eabi and -mcpu=cortex-m0plus… i’ve recently learned about the (undocumented) zig clang sub-command, which accepted these options as expected…

treating zig as my “clang installation”, where would a header like <stddef.h> be found???

more important, i currently call ld.lld directly – passing it a link to libc_v6m_t_le_eabi_small.a… for my purposes, the latter library contains definitions of run-time functions like __aeabi_uidiv …

how would/could i handle this using zig clang ???

tobyjaffey · January 27, 2025, 8:45pm

I haven’t had a chance to try it myself yet, but gatz looks like another way to setup these options. GitHub - haydenridd/gcc-arm-to-zig: Utilities for porting Cortex-M projects from arm-none-eabi-gcc compiler to Zig.

vulpesx · January 28, 2025, 3:26am

afaik zig clang is identical to zig cc which is documented
edit: nvm

AndrewKraevskii · January 28, 2025, 9:18am

They are not identical. zig clang jumps in clangMain immediately and zig cc parses flags and does some stuff before jumping into clangMain.

github.com

ziglang/zig/blob/183bb8b08403ab594cdc543c2db2503e7eac0052/src/main.zig#L296-L309


      
          } else if (mem.eql(u8, cmd, "clang") or
              mem.eql(u8, cmd, "-cc1") or mem.eql(u8, cmd, "-cc1as"))
          {
              dev.check(.clang_command);
              return process.exit(try clangMain(arena, args));
          } else if (mem.eql(u8, cmd, "ld.lld") or
              mem.eql(u8, cmd, "lld-link") or
              mem.eql(u8, cmd, "wasm-ld"))
          {
              dev.check(.lld_linker);
              return process.exit(try lldMain(arena, args, true));
          } else if (mem.eql(u8, cmd, "cc")) {
              dev.check(.cc_command);
              return buildOutputType(gpa, arena, args, .cc);