tree 244420b87851a0c4e930845816e39102cf558305
parent b975d9d903f7a60510393d438a086294ab086dea
author Eylon Krause <eylon1909@gmail.com> 1783594082 +0300
committer Eylon Krause <eylon1909@gmail.com> 1788421379 +0300

[preprocessor] Fix crash/hang on truncated callable macro invocation

GenerateBypassWhiteSpaces dereferences the stream iterator (**iterator) with no
end guard, relying on every stream ending in a kept EOF token. The streams
re-lexed for macro expansion in ExpandText, ExpandMacro, HandleInclude and the
standalone tool strip the EOF (loop stops on !isEOF()), so a callable macro
invocation truncated at end-of-stream (e.g. `define A(x) hello `A followed by
`A(1)) makes the streamer return the view's end() iterator and the deref reads
past the end -> SIGSEGV. An included file ending in a callable macro crashes the
same way; a '(' with no ')' spins forever.

Restore the kept-EOF sentinel on each re-lexed stream so the whitespace-skip
loop stops at EOF and callers return a diagnostic instead of dereferencing past
the end: append the EOF sentinel in all four stream builders; break on it in the
two token-pulling loops so it is not forwarded; skip it when splicing an included
child stream into the parent; and break on EOF in the argument-scanning loop
(the one caller that did not handle a mid-scan EOF, which otherwise hangs on a
'(' without ')'). Also record the "callable macro without ()" error in
preprocess_data_.errors instead of silently swallowing it (requires making
ConsumeAndParseMacroCall non-static).

Adds TruncatedCallableMacroDoesNotCrash. Existing preprocessor and analyzer test
suites pass. Unbounded macro self-recursion is a separate pre-existing bug and
is not addressed here.

Signed-off-by: Eylon Krause <eylon1909@gmail.com>