Improve lit "native" feature to check if the native backend is builtin

[mehdi_amini]

Summary

The goal is to have 'ninja check' passing even if the X86 backend is
not built.

[filcab]

test/lit.cfg

340

Interesting, target_triple seems to be set (in cmake) to LLVM_HOST_TRIPLE (unless explicitly set), without caring about the backends being compiled.

Should we change the target_triple logic instead of this, though?

What's the value of "target_triple" when we don't have the current target selected? Is that value appropriate?

[mehdi_amini]

landed

test/lit.cfg

 if not 'hexagon' in config.target_triple and not re.match(r'^x86_64.*-(mingw32|windows-gnu|win32)', config.target_triple):
     config.available_features.add("object-emission")
 
 if config.have_zlib == "1":
     config.available_features.add("zlib")
 else:
     config.available_features.add("nozlib")
 
-# Native compilation: host arch == target arch
+# Native compilation: host arch == target arch and native backend built-in
 # FIXME: Consider cases that target can be executed
 # even if host_triple were different from target_triple.
-if config.host_triple == config.target_triple:
+if config.host_triple == config.target_triple and \
+   config.native_target in config.targets_to_build:
     config.available_features.add("native")
 
 import subprocess
 
 def have_ld_plugin_support():
     if not os.path.exists(os.path.join(config.llvm_shlib_dir, 'LLVMgold.so')):
         return False
 

test/lit.site.cfg.in

 config.ocamlfind_executable = "@OCAMLFIND@"
 config.have_ocamlopt = "@HAVE_OCAMLOPT@"
 config.have_ocaml_ounit = "@HAVE_OCAML_OUNIT@"
 config.ocaml_flags = "@OCAMLFLAGS@"
 config.go_executable = "@GO_EXECUTABLE@"
 config.enable_shared = @ENABLE_SHARED@
 config.enable_assertions = @ENABLE_ASSERTIONS@
 config.targets_to_build = "@TARGETS_TO_BUILD@"
+config.native_target = "@LLVM_NATIVE_ARCH@"
 config.llvm_bindings = "@LLVM_BINDINGS@".split(' ')
 config.host_os = "@HOST_OS@"
 config.host_arch = "@HOST_ARCH@"
 config.host_cc = "@HOST_CC@"
 config.host_cxx = "@HOST_CXX@"
 config.host_ldflags = "@HOST_LDFLAGS@"
 config.llvm_use_intel_jitevents = "@LLVM_USE_INTEL_JITEVENTS@"
 config.llvm_use_sanitizer = "@LLVM_USE_SANITIZER@"