On Tue, Jan 11, 2022 at 4:35 PM Brendan Higgins
<brendanhiggins@xxxxxxxxxx> wrote:
>
> On Tue, Jan 11, 2022 at 2:42 PM Daniel Latypov <dlatypov@xxxxxxxxxx> wrote:
> >
> > This is per Linus's suggestion in [1].
> >
> > The issue there is that every KUNIT_EXPECT/KUNIT_ASSERT puts a
> > kunit_assert object onto the stack. Normally we rely on compilers to
> > elide this, but when that doesn't work out, this blows up the stack
> > usage of kunit test functions.
> >
> > We can move some data off the stack by making it static.
> > This change introduces a new `struct kunit_loc` to hold the file and
> > line number and then just passing assert_type (EXPECT or ASSERT) as an
> > argument.
> >
> > In [1], it was suggested to also move out the format string as well, but
> > users could theoretically craft a format string at runtime, so we can't.
> >
> > This change leaves a copy of `assert_type` in kunit_assert for now
> > because cleaning up all the macros to not pass it around is a bit more
> > involved.
> >
> > Here's an example of the expanded code for KUNIT_FAIL():
> > if (__builtin_expect(!!(!(false)), 0)) {
> > static const struct kunit_loc loc = { .file = ... };
> > struct kunit_fail_assert __assertion = { .assert = { .type ... };
> > kunit_do_failed_assertion(test, &loc, KUNIT_EXPECTATION, &__assertion.assert, ...);
> > };
> >
> > [1] https://groups.google.com/g/kunit-dev/c/i3fZXgvBrfA/m/VULQg1z6BAAJ
> >
> > Signed-off-by: Daniel Latypov <dlatypov@xxxxxxxxxx>
> > Suggested-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
> > Reviewed-by: David Gow <davidgow@xxxxxxxxxx>
>
> One question below, but other than that,
>
> Reviewed-by: Brendan Higgins <brendanhiggins@xxxxxxxxxx>
>
> > ---
> > include/kunit/assert.h | 25 ++++++++++++++++---------
> > include/kunit/test.h | 12 +++++++++++-
> > lib/kunit/assert.c | 9 +++++----
> > lib/kunit/test.c | 15 +++++++++------
> > 4 files changed, 41 insertions(+), 20 deletions(-)
> >
> > diff --git a/include/kunit/assert.h b/include/kunit/assert.h
> > index 3da6c792496c..4f91dbdb886a 100644
> > --- a/include/kunit/assert.h
> > +++ b/include/kunit/assert.h
> > @@ -28,11 +28,21 @@ enum kunit_assert_type {
> > KUNIT_EXPECTATION,
> > };
> >
> > +/**
> > + * struct kunit_loc - Identifies the source location of a line of code.
> > + * @line: the line number in the file.
> > + * @file: the file name.
> > + */
> > +struct kunit_loc {
> > + int line;
> > + const char *file;
> > +};
> > +
> > +#define KUNIT_CURRENT_LOC { .file = __FILE__, .line = __LINE__ }
> > +
> > /**
> > * struct kunit_assert - Data for printing a failed assertion or expectation.
> > * @type: the type (either an expectation or an assertion) of this kunit_assert.
> > - * @line: the source code line number that the expectation/assertion is at.
> > - * @file: the file path of the source file that the expectation/assertion is in.
> > * @message: an optional message to provide additional context.
> > * @format: a function which formats the data in this kunit_assert to a string.
> > *
> > @@ -40,9 +50,7 @@ enum kunit_assert_type {
> > * format a string to a user reporting the failure.
> > */
> > struct kunit_assert {
> > - enum kunit_assert_type type;
> > - int line;
> > - const char *file;
> > + enum kunit_assert_type type; // TODO(dlatypov@xxxxxxxxxx): delete this
>
> Can you provide some context for this?
NVM, I saw the context in the next patch. Could you maybe mention that
it is removed in a later patch in the comment?
> > struct va_format message;
> > void (*format)(const struct kunit_assert *assert,
> > struct string_stream *stream);
> > @@ -65,14 +73,13 @@ struct kunit_assert {
> > */
> > #define KUNIT_INIT_ASSERT_STRUCT(assert_type, fmt) { \
> > .type = assert_type, \
> > - .file = __FILE__, \
> > - .line = __LINE__, \
> > .message = KUNIT_INIT_VA_FMT_NULL, \
> > .format = fmt \
> > }
> >
> > -void kunit_base_assert_format(const struct kunit_assert *assert,
> > - struct string_stream *stream);
> > +void kunit_assert_prologue(const struct kunit_loc *loc,
> > + enum kunit_assert_type type,
> > + struct string_stream *stream);
> >
> > void kunit_assert_print_msg(const struct kunit_assert *assert,
> > struct string_stream *stream);
> > diff --git a/include/kunit/test.h b/include/kunit/test.h
> > index 25ea3bce6663..7b752175e614 100644
> > --- a/include/kunit/test.h
> > +++ b/include/kunit/test.h
