diff options
author | Quentin Carbonneaux <quentin@c9x.me> | 2021-11-08 10:46:20 +0100 |
---|---|---|
committer | Quentin Carbonneaux <quentin@c9x.me> | 2021-11-08 11:29:36 +0100 |
commit | cd095a44db262351b09ea144a44b76e22d62c77a (patch) | |
tree | ab9489f2084a5ebced26504b03c85ec104369708 /test/mem2.ssa | |
parent | 0d68986b6f6aa046ab13776f39cc37b67b3477ba (diff) | |
download | roux-cd095a44db262351b09ea144a44b76e22d62c77a.tar.gz |
fix for sloppy reg->mem in arm64 abi
Michael found a bug where some copies from registers to memory in the arm64 abi clobber the stack. The test case is: type :T = { w } function w $f() { @start %p =:T call $g() %x =w loadw %p ret %x } qbe will write 4 bytes out of bounds when pulling the result struct from its register. The same bug can be observed if :T's definition is {w 3}; in this case qbe writes 16 bytes in a slot of 12 bytes. This patch changes stkblob() to use the rounded argument size if it is going to be restored from registers. Relatedly, mem->reg loads for structs with size < 16 and != 8, are treated a bit sloppily both in the arm64 and in the sysv abis. That is much less harmful than the present bug.
Diffstat (limited to 'test/mem2.ssa')
0 files changed, 0 insertions, 0 deletions