Implement -print-file-name (and fix -print-search-dirs) (#17229)

ChangeLog.md

@@ -20,6 +20,8 @@ See docs/process.md for more on how version tagging works.
 
 3.2.0
 -----
+- emcc now accepts `-print-file-name` and reports the correct library paths in
+  `-print-search-dirs`.
 - `tools/file_packager` no longer generates (or requires) any "pre-js" code when
   running in `--embed-file` mode.  Instead the embedded files are loaded at
   static constructor time.

emcc.py

@@ -1125,8 +1125,9 @@ def run(args):
 
   shared.check_sanity()
 
-  if '-print-search-dirs' in args:
-    return run_process([clang, '-print-search-dirs'], check=False).returncode
+  passthrough_flags = ['-print-search-dirs', '-print-libgcc-file-name']
+  if any(a in args for a in passthrough_flags) or any(a.startswith('-print-file-name=') for a in args):
+    return run_process([clang] + args + get_cflags(args), check=False).returncode
 
   ## Process argument and setup the compiler
   state = EmccState(args)

tests/test_other.py

@@ -614,9 +614,15 @@ def test_emcc_cflags(self):
     self.assertContained('hello, world!', self.run_js('a.out.js'))
 
   def test_emcc_print_search_dirs(self):
-    result = self.run_process([EMCC, '-print-search-dirs'], stdout=PIPE, stderr=PIPE)
-    self.assertContained('programs: =', result.stdout)
-    self.assertContained('libraries: =', result.stdout)
+    output = self.run_process([EMCC, '-print-search-dirs'], stdout=PIPE).stdout
+    self.assertContained('programs: =', output)
+    self.assertContained('libraries: =', output)
+    self.assertContained(str(shared.Cache.get_lib_dir(absolute=True)), output)
+
+  def test_emcc_print_file_name(self):
+    self.run_process([EMBUILDER, 'build', 'libc'])
+    output = self.run_process([EMCC, '-print-file-name=libc.a'], stdout=PIPE).stdout
+    self.assertContained(shared.Cache.get_lib_name('libc.a'), output)
 
   def test_emar_em_config_flag(self):
     # Test that the --em-config flag is accepted but not passed down do llvm-ar.