I'm about to add fields to virStorageFileMetadata, which means
also adding fields to the testFileData struct in virstoragetest.
Alas, adding even one pointer on an x86_64 machine gave me a
dreaded compiler error:
virstoragetest.c:712:1: error: the frame size of 4208 bytes is larger than 4096 bytes [-Werror=frame-larger-than=]
After some experimentation, I realized that each test was creating
yet another testChainData (which contains testFileData) on the stack;
forcing the reuse of one of these structures instead of creating a
fresh one each time drastically reduces the size requirements. While
at it, I also got rid of a lot of intermediate structs, with some
macro magic that lets me directly build up the destination chains
inline.
For a bit more insight into what this patch does:
The old code uses an intermediate variable as a fixed-size array
of structs:
testFileData chain[] = { a, b };
data.files = chain;
In the new code, the use of VIR_FLATTEN_* allows the TEST_CHAIN()
macro to still take a single argument for each chain, but now of
the form '(a, b)', where it is turned into the var-args 'a, b'
multiple arguments understood by TEST_ONE_CHAIN(). Thus, the
new code avoids an intermediate variable, and directly provides
the list of pointers to be assigned into array elements:
data.files = { &a, &b };
* tests/virstoragetest.c (mymain): Rewrite TEST_ONE_CHAIN to
reuse the same struct for each test, and to take the data
inline rather than via intermediate variables.
(testChainData): Use bounded array of pointers instead of
unlimited array of struct.
(testStorageChain): Reflect struct change.
Signed-off-by: Eric Blake <eblake@redhat.com>
d1a1d841db