charmxi: do not crash on serial blocks when run without -orig-file

[lvkale]

Cause

processAst in src/xlat-i/xi-main.C set cur_file = origFile = origFile_;. origFile_ is NULL unless charmxi is given -orig-file. charmc always passes that flag, but direct callers of charmxi usually do not. SerialConstruct::generateCode (src/xlat-i/sdag/constructs/Serial.C) writes cur_file into a #line directive through XStr::append(const char*), which calls strlen on the NULL pointer. As a result, any non-empty serial block made charmxi segfault. The other users of cur_file print it in diagnostics: the SDAG-constructor error in SdagEntry.C and the error reporters in xi-util.C. They also crashed instead of reporting the error.

Fix

When no -orig-file is given, cur_file falls back to the input file name, or to STDIN when charmxi reads standard input. readFile already uses the same fallback while parsing. origFile itself is unchanged.

Reproducer

mainmodule t {
  mainchare Main {
    entry Main(CkArgMsg*);
    entry void run() {
      serial { int x = 1; (void)x; }
    };
  };
};

invocation	before	after
charmxi t.ci	exit 139 (SIGSEGV)	exit 0, t.def.h has #line 5 "t.ci"
charmxi < t.ci	exit 139	exit 0
charmxi -orig-file t.ci t.ci	exit 0	exit 0, #line 5 "t.ci"

Regression test

tests/charm++/charmxi_parsing gains SerialNoOrigFile.ci and a test-charmxi-direct target, which is part of make test. The target runs bin/charmxi directly on that file without -orig-file and checks that the generated .def.h has a #line directive naming the .ci file. With the unfixed charmxi the target fails with a segmentation fault.

🤖 Generated with Claude Code