[dexter] Force dexter tests to use the host triple

[Orlando]

Summary

If the default target and host triple don't match then print the following
message when the lit test runs:

Forcing dexter tests to use host triple {HOST_TRIPLE}.

If we can't target the host arch then, when lit runs, we mark
the dexter test directories as UNSUPPORTED and print the message:

Host triple {HOST_TRIPLE} not supported. Skipping dexter tests in
the debuginfo-tests project.

[Orlando]

debuginfo-tests/lit.cfg.py

93

@jmorse pointed out that this will fail to notice arm64 == aarch64. He's asked about this for XFAILS on llvm-dev (titled "Repeated names for architecture, aarch64 and arm64", google groups link here). For this patch I could add a special case check for it, but is there something better I could do?

[Orlando]

+ Split the targets_to_build list

Some more detail about this patch: dexter tests are end-to-end (built and run from source) and currently configured to target the default target and run on the host. This doesn't work when the default target isn't the same as the host. This patch forces dexter tests to target the host machine if possible.

[rnk]

lgtm

debuginfo-tests/lit.cfg.py

93

I think there are other normalization issues. For example, thumbv7-*-* triples. You could construct a set of targets, and if the set contains ARM or AArch64, add in known aliases for those targets to the set. It won't be able to handle every odd case, but it's obvious how to extend the logic to handle future aliases if they come up.

[Orlando]

Thanks @rnk! I will land this shortly.

+ Added a targets set which we can add arch aliases to.

[Orlando]

Rebase.

debuginfo-tests/dexter-tests/lit.local.cfg

+if 'dexter' not in config.available_features:
+    config.unsupported = True

debuginfo-tests/dexter/feature_tests/lit.local.cfg

+if 'dexter' not in config.available_features:
+    config.unsupported = True
+
 config.name = "DExTer feature tests"
 config.suffixes = ['.cpp', '.c', '.test']

debuginfo-tests/lit.cfg.py

 if not hasattr(config, 'clang_src_dir'):
     config.clang_src_dir = ""
 llvm_config.use_clang()
 
 if config.llvm_use_sanitizer:
     # Propagate path to symbolizer for ASan/MSan.
     llvm_config.with_system_environment(
         ['ASAN_SYMBOLIZER_PATH', 'MSAN_SYMBOLIZER_PATH'])
-llvm_config.with_environment('PATHTOCLANG', llvm_config.config.clang)
-llvm_config.with_environment('PATHTOCLANGPP', llvm_config.use_llvm_tool('clang++'))
-llvm_config.with_environment('PATHTOCLANGCL', llvm_config.use_llvm_tool('clang-cl'))
+
+def add_host_triple(clang):
+  return '{} --target={}'.format(clang, config.host_triple)
+
+# The set of arches we can build.
+targets = set(config.targets_to_build)
+# Add aliases to the target set.
+if 'AArch64' in targets:
+  targets.add('arm64')
+if 'ARM' in config.targets_to_build:
+  targets.add('thumbv7')
+
+def can_target_host():
+  # Check if the targets set contains anything that looks like our host arch.
+  # The arch name in the triple and targets set may be spelled differently
+  # (e.g. x86 vs X86).
+  return any(config.host_triple.lower().startswith(x.lower())
+             for x in targets)
+
+# Dexter tests run on the host machine. If the host arch is supported add
+# 'dexter' as an available feature and force the dexter tests to use the host
+# triple.
+if can_target_host():
+  config.available_features.add('dexter')
+  if config.host_triple != config.target_triple:
+    print('Forcing dexter tests to use host triple {}.'.format(config.host_triple))
+  llvm_config.with_environment('PATHTOCLANG',
+                               add_host_triple(llvm_config.config.clang))
+  llvm_config.with_environment('PATHTOCLANGPP',
+                               add_host_triple(llvm_config.use_llvm_tool('clang++')))
+  llvm_config.with_environment('PATHTOCLANGCL',
+                               add_host_triple(llvm_config.use_llvm_tool('clang-cl')))
+else:
+  print('Host triple {} not supported. Skipping dexter tests in the '
+        'debuginfo-tests project.'.format(config.host_triple))
 
 # Check which debuggers are available:
 built_lldb = llvm_config.use_llvm_tool('lldb', search_env='CLANG')
 lldb_path = None
 if built_lldb is not None:
     lldb_path = built_lldb
 elif lit.util.which('lldb') is not None:
     lldb_path = lit.util.which('lldb')

debuginfo-tests/lit.site.cfg.py.in

 @LIT_SITE_CFG_IN_HEADER@
 
 import sys
 import lit.util
 
+config.targets_to_build = "@TARGETS_TO_BUILD@".split()
 config.llvm_src_root = "@LLVM_SOURCE_DIR@"
 config.llvm_tools_dir = "@LLVM_TOOLS_DIR@"
 config.llvm_libs_dir = "@LLVM_LIBS_DIR@"
 config.llvm_shlib_dir = "@SHLIBDIR@"
 config.lit_tools_dir = "@LLVM_LIT_TOOLS_DIR@"
 config.llvm_plugin_ext = "@LLVM_PLUGIN_EXT@"
 config.debuginfo_tests_obj_root = "@DEBUGINFO_TESTS_BINARY_DIR@"
 config.debuginfo_tests_src_root = "@DEBUGINFO_TESTS_SOURCE_DIR@"