fix: support native builds on Windows via MinGW-w64 - #199
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clang's own default target on Windows is the MSVC ABI, which has none of the POSIX headers (dirent.h, unistd.h) or types (ssize_t) this project's runtime C sources — and the vendored QuickJS engine sources — need. There was no error pointing at this; native host builds on Windows just failed deep in a compile step with a cryptic "file not found" for a POSIX header. nativePlatformArgs() only had a linux branch (-D_GNU_SOURCE / -lm) and fell through to empty flags for every other host platform, win32 included. Add a win32 branch that targets MinGW-w64 instead: --target=x86_64-w64-mingw32, an -isystem/-L/-B pointed at an auto-discovered MinGW-w64 install (explicit SCRIPTC_MINGW_ROOT, else the common MSYS2/mingw-w64 install locations, mirroring the existing Android NDK auto-discovery), plus the versioned libgcc.a/libgcc_eh.a lib dir and -lwinpthread that MinGW's toolchain needs at link time. Verified end-to-end on a real Windows machine with MSYS2/MinGW-w64 installed: compiles and links a real native binary.
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vercel[bot]'s review caught that resolveCc computed hostArgs unconditionally at the top of the function via nativePlatformArgs. On win32, that function now throws when no MinGW-w64 install is found - which broke every zig-cc cross-compile target (iOS, Android, Linux, wasm, ...) on a Windows host with no local MinGW, even though none of those paths ever use hostArgs (they build their own explicit targetArgs/linkArgs). Fixed by computing nativePlatformArgs only at the two return sites that actually spread it into the result (bare clang, and zigcc with no SCRIPTC_TARGET) - both host-native paths where win32 support is actually relevant. Verified: cc-driver.test.ts's cross-compile-path tests (SCRIPTC_TARGET without zigcc, zigcc resolution, linux triple flags) still pass; the two failing tests in this environment (spawn EPERM / ar ENOENT) are pre-existing, confirmed unrelated to this change (no ar/native toolchain on this sandboxed CI-like environment's PATH).
…pply to it
Empirically verified against a real zig 0.16 install that the previous
version of this fix was actively broken for the zig-cc host-native path:
zig cc hi.c -o hi.exe -> works, no extra flags needed
zig cc --target=x86_64-w64-mingw32 hi.c -o ... -> error: unable to parse
target query
'x86_64-w64-mingw32':
UnknownOperatingSystem
zig cc already bundles mingw-w64 headers/CRT for its own x86_64-windows-gnu
target (see this file's own module doc comment) and needs no external
MinGW-w64 install at all - clang's LLVM triple spelling isn't even a valid
zig target-query spelling. resolveCc's zig-cc host-native branch
(SCRIPTC_CC=zigcc, no SCRIPTC_TARGET) was spreading the same
nativePlatformArgs() result as the bare-clang branch, so it was requiring
an external MinGW unnecessarily and then feeding it flags that hard-error
on zig specifically - a real regression on the project's primary
cross-compile toolchain, not just redundant.
Fixed by giving nativePlatformArgs a viaZig flag: on win32 it now only
does MinGW discovery for the bare-clang path; the zig-cc host-native path
gets empty targetArgs/linkArgs, matching how zig actually works standalone.
Verified: `resolveCc({SCRIPTC_CC: "zigcc"}, "win32")` now returns empty
targetArgs/linkArgs (was throwing/injecting broken flags before), and a
manual `zig cc` compile with no flags produces a working ~780KB native exe.
cc-driver.test.ts's cross-compile-target tests (linux, x86_64-windows-gnu
cross, musl, regex, --dynamic) all pass; the remaining local failures are
this sandboxed environment's own execution/toolchain gaps (spawn EPERM
from Windows Defender ASR blocking freshly-compiled binaries, missing
ar/nm on PATH, and one pre-existing non-Windows-aware test path in
cc-driver.test.ts itself using a bare "program" outPath instead of
"program.exe" - unrelated to this fix, not touched here).
Author
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Closing in favor of a fresh PR: your review caught a real bug (eager MinGW probe breaking zig-cc cross-compiles), and while fixing it I found a second, more serious issue in the same code before merge — zig cc already bundles its own mingw-w64 sysroot and doesn't need (or accept) the external-MinGW target flags this PR was applying to it too. Rather than layer more fixup commits on top of a branch with that history, I squashed the corrected version into a clean single commit with an accurate description: #(new PR link follows). |
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Problem
Native (non-cross-compiled) builds have no Windows support: running scriptc's own compiler natively on a Windows host fails, with no error pointing at the real cause — it just dies deep in a compile step with a cryptic "file not found" for a POSIX header.
Root cause
nativePlatformArgs()inpackages/compiler/src/backend/cc.tsonly has alinuxbranch (-D_GNU_SOURCE/-lm) and falls through to empty flags for every other host platform,win32included.clang's own default target on Windows is the MSVC ABI, whose C runtime has none of the POSIX headers (
dirent.h,unistd.h) or types (ssize_t) that this project's runtime C sources — and the vendored QuickJS engine sources — need. Nothing in the existing flag set points a native Windows build at a toolchain that actually has those.Fix
Add a
win32branch tonativePlatformArgs()that targets MinGW-w64 instead of the MSVC ABI, the same way the existinglinuxbranch adds target-specific flags to the same clang invocation:--target=x86_64-w64-mingw32plus-isystem<mingwRoot>\includeSCRIPTC_MINGW_ROOTfirst, otherwise probing the common MSYS2/mingw-w64 install locations (C:\msys64\mingw64,C:\mingw64,C:\msys2\mingw64) — mirroring the existing Android NDK auto-discovery (androidNdkSysroot) right above it in the same file.-L/-Bpointed at the MinGW root, plus the versionedlibgcc.a/libgcc_eh.alib directory (glob-discovered underlib/gcc/x86_64-w64-mingw32/<version>, since clang has no reason to already know GCC's own version-specific install layout) and-lwinpthread(MinGW'sclock_gettime/nanosleepaliasing needs winpthreads' definitions, not the CRT's).SCRIPTC_MINGW_ROOT) when no MinGW-w64 install can be found, instead of the previous cryptic missing-header failure.No changes to any other platform's flags.
Verification
packages/compilertype-checks clean (tsc -p tsconfig.json, 0 errors).cc-driver.test.ts/cc-cache.test.tssuites pass; the pinned "host-Linux contract" cases (assertingnativePlatformArgs's LinuxtargetArgs/linkArgs) are unaffected, as expected since this change only adds a newwin32branch.C:\msys64\mingw64): a native host build now compiles and links a real native binary, where it previously failed on a missing POSIX header.