On Wed, Jan 26, 2022 at 5:00 AM Daniel Latypov <dlatypov@xxxxxxxxxx> wrote:
>
> If the compiler doesn't optimize them away, each kunit assertion (use of
> KUNIT_EXPECT_EQ, etc.) can use 88 bytes of stack space in the worst and
> most common case. This has led to compiler warnings and a suggestion
> from Linus to move data from the structs into static const's where
> possible [1].
>
> This builds upon [2] which did so for the base struct kunit_assert type.
> That only reduced sizeof(struct kunit_binary_assert) from 88 to 64.
>
> Given these are by far the most commonly used asserts, this patch
> factors out the textual representations of the operands and comparator
> into another static const, saving 16 more bytes.
>
> In detail, KUNIT_EXPECT_EQ(test, 2 + 2, 5) yields the following struct
> (struct kunit_binary_assert) {
> .assert = <struct kunit_assert>,
> .operation = "==",
> .left_text = "2 + 2",
> .left_value = 4,
> .right_text = "5",
> .right_value = 5,
> }
> After this change
> static const struct kunit_binary_assert_text __text = {
> .operation = "==",
> .left_text = "2 + 2",
> .right_text = "5",
> };
> (struct kunit_binary_assert) {
> .assert = <struct kunit_assert>,
> .text = &__text,
> .left_value = 4,
> .right_value = 5,
> }
>
> This also DRYs the code a bit more since these str fields were repeated
> for the string and pointer versions of kunit_binary_assert.
>
> Note: we could name the kunit_binary_assert_text fields left/right
> instead of left_text/right_text. But that would require changing the
> macros a bit since they have args called "left" and "right" which would
> be substituted in `.left = #left` as `.2 + 2 = \"2 + 2\"`.
>
> [1] https://groups.google.com/g/kunit-dev/c/i3fZXgvBrfA/m/VULQg1z6BAAJ
> [2] https://lore.kernel.org/linux-kselftest/20220113165931.451305-6-dlatypov@xxxxxxxxxx/
>
> Signed-off-by: Daniel Latypov <dlatypov@xxxxxxxxxx>
> ---
This definitely _feels_ like it's adding a bit more complexity than
would be ideal by splitting this out into a separate function, but I
do agree that it's worth it.
I think left_text / right_text are good enough names, too: I wouldn't
bother trying to make them .left/.right.
Reviewed-by: David Gow <davidgow@xxxxxxxxxx>
Cheers,
-- David
> include/kunit/assert.h | 49 +++++++++++++++++++-----------------------
> include/kunit/test.h | 20 +++++++++++------
> lib/kunit/assert.c | 38 ++++++++++++++++----------------
> 3 files changed, 54 insertions(+), 53 deletions(-)
>
> diff --git a/include/kunit/assert.h b/include/kunit/assert.h
> index 649bfac9f406..4b52e12c2ae8 100644
> --- a/include/kunit/assert.h
> +++ b/include/kunit/assert.h
> @@ -150,14 +150,25 @@ void kunit_ptr_not_err_assert_format(const struct kunit_assert *assert,
> .value = val \
> }
>
> +/**
> + * struct kunit_binary_assert_text - holds strings for &struct
> + * kunit_binary_assert and friends to try and make the structs smaller.
> + * @operation: A string representation of the comparison operator (e.g. "==").
> + * @left_text: A string representation of the left expression (e.g. "2+2").
> + * @right_text: A string representation of the right expression (e.g. "2+2").
> + */
> +struct kunit_binary_assert_text {
> + const char *operation;
> + const char *left_text;
> + const char *right_text;
> +};
> +
> /**
> * struct kunit_binary_assert - An expectation/assertion that compares two
> * non-pointer values (for example, KUNIT_EXPECT_EQ(test, 1 + 1, 2)).
> * @assert: The parent of this type.
> - * @operation: A string representation of the comparison operator (e.g. "==").
> - * @left_text: A string representation of the expression in the left slot.
> + * @text: Holds the textual representations of the operands and op (e.g. "==").
> * @left_value: The actual evaluated value of the expression in the left slot.
> - * @right_text: A string representation of the expression in the right slot.
> * @right_value: The actual evaluated value of the expression in the right slot.
> *
> * Represents an expectation/assertion that compares two non-pointer values. For
> @@ -166,10 +177,8 @@ void kunit_ptr_not_err_assert_format(const struct kunit_assert *assert,
> */
> struct kunit_binary_assert {
> struct kunit_assert assert;
> - const char *operation;
> - const char *left_text;
> + const struct kunit_binary_assert_text *text;
> long long left_value;
> - const char *right_text;
> long long right_value;
> };
>
> @@ -182,10 +191,8 @@ void kunit_binary_assert_format(const struct kunit_assert *assert,
> * kunit_binary_assert, kunit_binary_ptr_assert, etc.
> *
> * @format_func: a function which formats the assert to a string.
> - * @op_str: A string representation of the comparison operator (e.g. "==").
> - * @left_str: A string representation of the expression in the left slot.
> + * @text_: Pointer to a kunit_binary_assert_text.
> * @left_val: The actual evaluated value of the expression in the left slot.
> - * @right_str: A string representation of the expression in the right slot.
> * @right_val: The actual evaluated value of the expression in the right slot.
> *
> * Initializes a binary assert like kunit_binary_assert,
> @@ -194,16 +201,12 @@ void kunit_binary_assert_format(const struct kunit_assert *assert,
> * This is ultimately used by binary assertion macros like KUNIT_EXPECT_EQ, etc.
> */
> #define KUNIT_INIT_BINARY_ASSERT_STRUCT(format_func, \
> - op_str, \
> - left_str, \
> + text_, \
> left_val, \
> - right_str, \
> right_val) { \
> .assert = { .format = format_func }, \
> - .operation = op_str, \
> - .left_text = left_str, \
> + .text = text_, \
> .left_value = left_val, \
> - .right_text = right_str, \
> .right_value = right_val \
> }
>
> @@ -211,10 +214,8 @@ void kunit_binary_assert_format(const struct kunit_assert *assert,
> * struct kunit_binary_ptr_assert - An expectation/assertion that compares two
> * pointer values (for example, KUNIT_EXPECT_PTR_EQ(test, foo, bar)).
> * @assert: The parent of this type.
> - * @operation: A string representation of the comparison operator (e.g. "==").
> - * @left_text: A string representation of the expression in the left slot.
> + * @text: Holds the textual representations of the operands and op (e.g. "==").
> * @left_value: The actual evaluated value of the expression in the left slot.
> - * @right_text: A string representation of the expression in the right slot.
> * @right_value: The actual evaluated value of the expression in the right slot.
> *
> * Represents an expectation/assertion that compares two pointer values. For
> @@ -223,10 +224,8 @@ void kunit_binary_assert_format(const struct kunit_assert *assert,
> */
> struct kunit_binary_ptr_assert {
> struct kunit_assert assert;
> - const char *operation;
> - const char *left_text;
> + const struct kunit_binary_assert_text *text;
> const void *left_value;
> - const char *right_text;
> const void *right_value;
> };
>
> @@ -238,10 +237,8 @@ void kunit_binary_ptr_assert_format(const struct kunit_assert *assert,
> * struct kunit_binary_str_assert - An expectation/assertion that compares two
> * string values (for example, KUNIT_EXPECT_STREQ(test, foo, "bar")).
> * @assert: The parent of this type.
> - * @operation: A string representation of the comparison operator (e.g. "==").
> - * @left_text: A string representation of the expression in the left slot.
> + * @text: Holds the textual representations of the operands and comparator.
> * @left_value: The actual evaluated value of the expression in the left slot.
> - * @right_text: A string representation of the expression in the right slot.
> * @right_value: The actual evaluated value of the expression in the right slot.
> *
> * Represents an expectation/assertion that compares two string values. For
> @@ -250,10 +247,8 @@ void kunit_binary_ptr_assert_format(const struct kunit_assert *assert,
> */
> struct kunit_binary_str_assert {
> struct kunit_assert assert;
> - const char *operation;
> - const char *left_text;
> + const struct kunit_binary_assert_text *text;
> const char *left_value;
> - const char *right_text;
> const char *right_value;
> };
>
> diff --git a/include/kunit/test.h b/include/kunit/test.h
> index a93dfb8ff393..088ff394ae94 100644
> --- a/include/kunit/test.h
> +++ b/include/kunit/test.h
> @@ -874,16 +874,19 @@ void kunit_do_failed_assertion(struct kunit *test,
> do { \
> typeof(left) __left = (left); \
> typeof(right) __right = (right); \
> + static const struct kunit_binary_assert_text __text = { \
> + .operation = #op, \
> + .left_text = #left, \
> + .right_text = #right, \
> + }; \
> \
> KUNIT_ASSERTION(test, \
> assert_type, \
> __left op __right, \
> assert_class, \
> KUNIT_INIT_BINARY_ASSERT_STRUCT(format_func, \
> - #op, \
> - #left, \
> + &__text, \
> __left, \
> - #right, \
> __right), \
> fmt, \
> ##__VA_ARGS__); \
> @@ -928,17 +931,20 @@ do { \
> ...) \
> do { \
> const char *__left = (left); \
> - const char *__right = (right); \
> + const char *__right = (right); \
> + static const struct kunit_binary_assert_text __text = { \
> + .operation = #op, \
> + .left_text = #left, \
> + .right_text = #right, \
> + }; \
> \
> KUNIT_ASSERTION(test, \
> assert_type, \
> strcmp(__left, __right) op 0, \
> kunit_binary_str_assert, \
> KUNIT_INIT_BINARY_ASSERT_STRUCT(kunit_binary_str_assert_format,\
> - #op, \
> - #left, \
> + &__text, \
> __left, \
> - #right, \
> __right), \
> fmt, \
> ##__VA_ARGS__); \
> diff --git a/lib/kunit/assert.c b/lib/kunit/assert.c
> index c9c7ee0dfafa..d00d6d181ee8 100644
> --- a/lib/kunit/assert.c
> +++ b/lib/kunit/assert.c
> @@ -122,18 +122,18 @@ void kunit_binary_assert_format(const struct kunit_assert *assert,
>
> string_stream_add(stream,
> KUNIT_SUBTEST_INDENT "Expected %s %s %s, but\n",
> - binary_assert->left_text,
> - binary_assert->operation,
> - binary_assert->right_text);
> - if (!is_literal(stream->test, binary_assert->left_text,
> + binary_assert->text->left_text,
> + binary_assert->text->operation,
> + binary_assert->text->right_text);
> + if (!is_literal(stream->test, binary_assert->text->left_text,
> binary_assert->left_value, stream->gfp))
> string_stream_add(stream, KUNIT_SUBSUBTEST_INDENT "%s == %lld\n",
> - binary_assert->left_text,
> + binary_assert->text->left_text,
> binary_assert->left_value);
> - if (!is_literal(stream->test, binary_assert->right_text,
> + if (!is_literal(stream->test, binary_assert->text->right_text,
> binary_assert->right_value, stream->gfp))
> string_stream_add(stream, KUNIT_SUBSUBTEST_INDENT "%s == %lld",
> - binary_assert->right_text,
> + binary_assert->text->right_text,
> binary_assert->right_value);
> kunit_assert_print_msg(message, stream);
> }
> @@ -150,14 +150,14 @@ void kunit_binary_ptr_assert_format(const struct kunit_assert *assert,
>
> string_stream_add(stream,
> KUNIT_SUBTEST_INDENT "Expected %s %s %s, but\n",
> - binary_assert->left_text,
> - binary_assert->operation,
> - binary_assert->right_text);
> + binary_assert->text->left_text,
> + binary_assert->text->operation,
> + binary_assert->text->right_text);
> string_stream_add(stream, KUNIT_SUBSUBTEST_INDENT "%s == %px\n",
> - binary_assert->left_text,
> + binary_assert->text->left_text,
> binary_assert->left_value);
> string_stream_add(stream, KUNIT_SUBSUBTEST_INDENT "%s == %px",
> - binary_assert->right_text,
> + binary_assert->text->right_text,
> binary_assert->right_value);
> kunit_assert_print_msg(message, stream);
> }
> @@ -190,16 +190,16 @@ void kunit_binary_str_assert_format(const struct kunit_assert *assert,
>
> string_stream_add(stream,
> KUNIT_SUBTEST_INDENT "Expected %s %s %s, but\n",
> - binary_assert->left_text,
> - binary_assert->operation,
> - binary_assert->right_text);
> - if (!is_str_literal(binary_assert->left_text, binary_assert->left_value))
> + binary_assert->text->left_text,
> + binary_assert->text->operation,
> + binary_assert->text->right_text);
> + if (!is_str_literal(binary_assert->text->left_text, binary_assert->left_value))
> string_stream_add(stream, KUNIT_SUBSUBTEST_INDENT "%s == \"%s\"\n",
> - binary_assert->left_text,
> + binary_assert->text->left_text,
> binary_assert->left_value);
> - if (!is_str_literal(binary_assert->right_text, binary_assert->right_value))
> + if (!is_str_literal(binary_assert->text->right_text, binary_assert->right_value))
> string_stream_add(stream, KUNIT_SUBSUBTEST_INDENT "%s == \"%s\"",
> - binary_assert->right_text,
> + binary_assert->text->right_text,
> binary_assert->right_value);
> kunit_assert_print_msg(message, stream);
> }
> --
> 2.35.0.rc2.247.g8bbb082509-goog
>
