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SubjectRe: [PATCH 1/4] kunit: remove format func from struct kunit_assert, get it to 0 bytes
On Sat, Oct 1, 2022 at 8:26 AM Daniel Latypov <dlatypov@google.com> wrote:
>
> Each calll to a KUNIT_EXPECT_*() macro creates a local variable which
> contains a struct kunit_assert.
>
> Normally, we'd hope the compiler would be able to optimize this away,
> but we've seen cases where it hasn't, see
> https://groups.google.com/g/kunit-dev/c/i3fZXgvBrfA/m/GbrMNej2BAAJ.
>
> In changes like commit 21957f90b28f ("kunit: split out part of
> kunit_assert into a static const"), we've moved more and more parts out
> of struct kunit_assert and its children types (kunit_binary_assert).
>
> This patch removes the final field and gets us to:
> sizeof(struct kunit_assert) == 0
> sizeof(struct kunit_binary_assert) == 24 (on UML x86_64).
>
> This also reduces the amount of macro plumbing going on at the cost of
> passing in one more arg to the base KUNIT_ASSERTION macro and
> kunit_do_failed_assertion().
>
> Signed-off-by: Daniel Latypov <dlatypov@google.com>
> ---

Very glad to see this finally happening: we've definitely still been
seeing these stack size warnings, so reducing the stack use is good

And as someone who has always been a little uneasy with the number of
nested macros, the simplification is also a big win.

Reviewed-by: David Gow <davidgow@google.com>

Cheers,
-- David



> include/kunit/assert.h | 28 ++++++----------------------
> include/kunit/test.h | 17 +++++++++++------
> lib/kunit/test.c | 7 ++++---
> 3 files changed, 21 insertions(+), 31 deletions(-)
>
> diff --git a/include/kunit/assert.h b/include/kunit/assert.h
> index 4b52e12c2ae8..ace3de8d1ee7 100644
> --- a/include/kunit/assert.h
> +++ b/include/kunit/assert.h
> @@ -42,16 +42,15 @@ struct kunit_loc {
>
> /**
> * struct kunit_assert - Data for printing a failed assertion or expectation.
> - * @format: a function which formats the data in this kunit_assert to a string.
> *
> * Represents a failed expectation/assertion. Contains all the data necessary to
> * format a string to a user reporting the failure.
> */
> -struct kunit_assert {
> - void (*format)(const struct kunit_assert *assert,
> - const struct va_format *message,
> - struct string_stream *stream);
> -};
> +struct kunit_assert {};
> +
> +typedef void (*assert_format_t)(const struct kunit_assert *assert,
> + const struct va_format *message,
> + struct string_stream *stream);
>
> void kunit_assert_prologue(const struct kunit_loc *loc,
> enum kunit_assert_type type,
> @@ -71,16 +70,6 @@ void kunit_fail_assert_format(const struct kunit_assert *assert,
> const struct va_format *message,
> struct string_stream *stream);
>
> -/**
> - * KUNIT_INIT_FAIL_ASSERT_STRUCT - Initializer for &struct kunit_fail_assert.
> - *
> - * Initializes a &struct kunit_fail_assert. Intended to be used in
> - * KUNIT_EXPECT_* and KUNIT_ASSERT_* macros.
> - */
> -#define KUNIT_INIT_FAIL_ASSERT_STRUCT { \
> - .assert = { .format = kunit_fail_assert_format }, \
> -}
> -
> /**
> * struct kunit_unary_assert - Represents a KUNIT_{EXPECT|ASSERT}_{TRUE|FALSE}
> * @assert: The parent of this type.
> @@ -110,7 +99,6 @@ void kunit_unary_assert_format(const struct kunit_assert *assert,
> * KUNIT_EXPECT_* and KUNIT_ASSERT_* macros.
> */
> #define KUNIT_INIT_UNARY_ASSERT_STRUCT(cond, expect_true) { \
> - .assert = { .format = kunit_unary_assert_format }, \
> .condition = cond, \
> .expected_true = expect_true \
> }
> @@ -145,7 +133,6 @@ void kunit_ptr_not_err_assert_format(const struct kunit_assert *assert,
> * KUNIT_EXPECT_* and KUNIT_ASSERT_* macros.
> */
> #define KUNIT_INIT_PTR_NOT_ERR_STRUCT(txt, val) { \
> - .assert = { .format = kunit_ptr_not_err_assert_format }, \
> .text = txt, \
> .value = val \
> }
> @@ -190,7 +177,6 @@ void kunit_binary_assert_format(const struct kunit_assert *assert,
> * KUNIT_INIT_BINARY_ASSERT_STRUCT() - Initializes a binary assert like
> * kunit_binary_assert, kunit_binary_ptr_assert, etc.
> *
> - * @format_func: a function which formats the assert to a string.
> * @text_: Pointer to a kunit_binary_assert_text.
> * @left_val: The actual evaluated value of the expression in the left slot.
> * @right_val: The actual evaluated value of the expression in the right slot.
> @@ -200,11 +186,9 @@ void kunit_binary_assert_format(const struct kunit_assert *assert,
> * fields but with different types for left_val/right_val.
> * This is ultimately used by binary assertion macros like KUNIT_EXPECT_EQ, etc.
> */
> -#define KUNIT_INIT_BINARY_ASSERT_STRUCT(format_func, \
> - text_, \
> +#define KUNIT_INIT_BINARY_ASSERT_STRUCT(text_, \
> left_val, \
> right_val) { \
> - .assert = { .format = format_func }, \
> .text = text_, \
> .left_value = left_val, \
> .right_value = right_val \
> diff --git a/include/kunit/test.h b/include/kunit/test.h
> index 840a2c375065..3476549106f7 100644
> --- a/include/kunit/test.h
> +++ b/include/kunit/test.h
> @@ -472,9 +472,10 @@ void kunit_do_failed_assertion(struct kunit *test,
> const struct kunit_loc *loc,
> enum kunit_assert_type type,
> const struct kunit_assert *assert,
> + assert_format_t assert_format,
> const char *fmt, ...);
>
> -#define KUNIT_ASSERTION(test, assert_type, pass, assert_class, INITIALIZER, fmt, ...) do { \
> +#define KUNIT_ASSERTION(test, assert_type, pass, assert_class, assert_format, INITIALIZER, fmt, ...) do { \
> if (unlikely(!(pass))) { \
> static const struct kunit_loc __loc = KUNIT_CURRENT_LOC; \
> struct assert_class __assertion = INITIALIZER; \
> @@ -482,6 +483,7 @@ void kunit_do_failed_assertion(struct kunit *test,
> &__loc, \
> assert_type, \
> &__assertion.assert, \
> + assert_format, \
> fmt, \
> ##__VA_ARGS__); \
> } \
> @@ -493,7 +495,8 @@ void kunit_do_failed_assertion(struct kunit *test,
> assert_type, \
> false, \
> kunit_fail_assert, \
> - KUNIT_INIT_FAIL_ASSERT_STRUCT, \
> + kunit_fail_assert_format, \
> + {}, \
> fmt, \
> ##__VA_ARGS__)
>
> @@ -524,6 +527,7 @@ void kunit_do_failed_assertion(struct kunit *test,
> assert_type, \
> !!(condition) == !!expected_true, \
> kunit_unary_assert, \
> + kunit_unary_assert_format, \
> KUNIT_INIT_UNARY_ASSERT_STRUCT(#condition, \
> expected_true), \
> fmt, \
> @@ -581,8 +585,8 @@ do { \
> assert_type, \
> __left op __right, \
> assert_class, \
> - KUNIT_INIT_BINARY_ASSERT_STRUCT(format_func, \
> - &__text, \
> + format_func, \
> + KUNIT_INIT_BINARY_ASSERT_STRUCT(&__text, \
> __left, \
> __right), \
> fmt, \
> @@ -639,8 +643,8 @@ do { \
> assert_type, \
> strcmp(__left, __right) op 0, \
> kunit_binary_str_assert, \
> - KUNIT_INIT_BINARY_ASSERT_STRUCT(kunit_binary_str_assert_format,\
> - &__text, \
> + kunit_binary_str_assert_format, \
> + KUNIT_INIT_BINARY_ASSERT_STRUCT(&__text, \
> __left, \
> __right), \
> fmt, \
> @@ -659,6 +663,7 @@ do { \
> assert_type, \
> !IS_ERR_OR_NULL(__ptr), \
> kunit_ptr_not_err_assert, \
> + kunit_ptr_not_err_assert_format, \
> KUNIT_INIT_PTR_NOT_ERR_STRUCT(#ptr, \
> __ptr), \
> fmt, \
> diff --git a/lib/kunit/test.c b/lib/kunit/test.c
> index b73d5bb5c473..53bf1793f915 100644
> --- a/lib/kunit/test.c
> +++ b/lib/kunit/test.c
> @@ -247,7 +247,7 @@ static void kunit_print_string_stream(struct kunit *test,
>
> static void kunit_fail(struct kunit *test, const struct kunit_loc *loc,
> enum kunit_assert_type type, const struct kunit_assert *assert,
> - const struct va_format *message)
> + assert_format_t assert_format, const struct va_format *message)
> {
> struct string_stream *stream;
>
> @@ -263,7 +263,7 @@ static void kunit_fail(struct kunit *test, const struct kunit_loc *loc,
> }
>
> kunit_assert_prologue(loc, type, stream);
> - assert->format(assert, message, stream);
> + assert_format(assert, message, stream);
>
> kunit_print_string_stream(test, stream);
>
> @@ -287,6 +287,7 @@ void kunit_do_failed_assertion(struct kunit *test,
> const struct kunit_loc *loc,
> enum kunit_assert_type type,
> const struct kunit_assert *assert,
> + assert_format_t assert_format,
> const char *fmt, ...)
> {
> va_list args;
> @@ -296,7 +297,7 @@ void kunit_do_failed_assertion(struct kunit *test,
> message.fmt = fmt;
> message.va = &args;
>
> - kunit_fail(test, loc, type, assert, &message);
> + kunit_fail(test, loc, type, assert, assert_format, &message);
>
> va_end(args);
>
> --
> 2.38.0.rc1.362.ged0d419d3c-goog
>
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