shit

src/lib/meson.py

@@ -1,5 +1,98 @@
+# A cross `llvm-config`. The target llvm-config is a glibc binary that can't run
+# on the (musl) build host, so instead of executing it we emulate the queries
+# meson/mesa make, reporting paths inside the sysroot. Self-configuring: it reads
+# the LLVM version, library soname, and built targets from the installed sysroot,
+# so it works for any LLVM consumer (mesa now, rust/etc. later) with no hardcoding.
+_LLVM_CONFIG_EMULATOR = r'''#!/usr/bin/env python3
+import glob, re, sys
+
+SYSROOT = "/sysroot"
+LIBDIR = SYSROOT + "/usr/lib"
+INCDIR = SYSROOT + "/usr/include"
+
+_major = ""
+for _p in sorted(glob.glob(LIBDIR + "/libLLVM-*.so*")):
+    _m = re.search(r"libLLVM-(\d+)", _p)
+    if _m:
+        _major = _m.group(1)
+        break
+
+_version = (_major + ".0.0") if _major else "0.0.0"
+try:
+    with open(INCDIR + "/llvm/Config/llvm-config.h") as _f:
+        _m = re.search(r'LLVM_VERSION_STRING\s+"([^"]+)"', _f.read())
+        if _m:
+            _version = _m.group(1)
+except OSError:
+    pass
+
+_targets = []
+try:
+    with open(INCDIR + "/llvm/Config/Targets.def") as _f:
+        _targets = re.findall(r"LLVM_TARGET\((\w+)\)", _f.read())
+except OSError:
+    pass
+if not _targets:
+    _targets = ["X86", "AMDGPU"]
+
+_GENERIC = (
+    "aggressiveinstcombine all all-targets analysis asmparser asmprinter "
+    "binaryformat bitreader bitstreamreader bitwriter cfguard codegen "
+    "codegentypes core coroutines coverage debuginfocodeview debuginfodwarf "
+    "debuginfomsf debuginfopdb demangle dlltooldriver engine executionengine "
+    "extensions frontenddriver frontendhlsl frontendoffloading frontendopenmp "
+    "fuzzmutate globalisel instcombine instrumentation interpreter ipo irreader "
+    "irprinter jitlink libdriver lineeditor linker lto mc mca mcdisassembler "
+    "mcjit mcparser native nativecodegen object objectyaml option orcjit "
+    "orcshared orctargetprocess passes profiledata remarks runtimedyld "
+    "scalaropts selectiondag support symbolize target targetparser textapi "
+    "transformutils vectorize windowsdriver windowsmanifest"
+).split()
+
+
+def _components():
+    comps = list(_GENERIC)
+    for t in _targets:
+        tl = t.lower()
+        comps += [tl, tl + "asmparser", tl + "codegen", tl + "desc",
+                  tl + "disassembler", tl + "info", tl + "targetmca", tl + "utils"]
+    return " ".join(sorted(set(comps)))
+
+
+_H = {
+    "--version": lambda: _version,
+    "--components": _components,
+    "--targets-built": lambda: " ".join(_targets),
+    "--prefix": lambda: SYSROOT + "/usr",
+    "--bindir": lambda: SYSROOT + "/usr/bin",
+    "--includedir": lambda: INCDIR,
+    "--libdir": lambda: LIBDIR,
+    "--cmakedir": lambda: LIBDIR + "/cmake/llvm",
+    "--has-rtti": lambda: "YES",
+    "--shared-mode": lambda: "shared",
+    "--libs": lambda: "-lLLVM-" + _major,
+    "--system-libs": lambda: "",
+    "--cflags": lambda: "-I" + INCDIR,
+    "--cppflags": lambda: ("-I" + INCDIR
+                           + " -D__STDC_CONSTANT_MACROS"
+                           + " -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS"),
+    "--cxxflags": lambda: ("-I" + INCDIR
+                           + " -D__STDC_CONSTANT_MACROS"
+                           + " -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS"),
+    "--ldflags": lambda: "-L" + LIBDIR,
+}
+
+for _a in sys.argv[1:]:
+    if _a in _H:
+        print(_H[_a]())
+'''
+
+
 def meson_cross_file(self):
     cross = self.build_dir / "meson-cross.ini"
+    llvm_config = self.build_dir / "llvm-config"
+    self.write_text(llvm_config, _LLVM_CONFIG_EMULATOR)
+    self.run("chmod", "+x", llvm_config)
     self.write_text(
         cross,
         f"""\
@@ -12,6 +105,8 @@ objcopy = '{self.triple}-objcopy'
 ranlib = '{self.triple}-ranlib'
 strip = '{self.triple}-strip'
 pkg-config = '{self.triple}-pkg-config'
+cmake = '/usr/bin/cmake'
+llvm-config = '{llvm_config}'
 
 [host_machine]
 system = 'linux'