tree 40c792198a41cc825498db506f7dbdb96a4e20d5
parent 6e3da6a94141e51e217dd1441cd631095b3ca016
author George Kulakowski <kulakowski@google.com> 1547254305 -0800
committer CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org> 1547268945 +0000

[abigen] Fix syscall generation for one argument and zero returns

The computation of how many C arguments to include would underflow in
the case that there were no abigen-level return values. This was not
noticed, as the value was only compared to be greater than zero, and
all existing syscalls with no return values have at least two
abigen-level parameters.

This was discovered by an experiment to make _zx_handle_close return
void. As it then has one parameter and no return values, the underflow
was observable.

Test: manual inspection of out/.../syscalls/definitions.h
Change-Id: I25a20a17fb939dbf069ae5e6ad132d3c70ccec99