From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tom Rini Date: Thu, 20 Sep 2018 09:25:52 -0400 Subject: [U-Boot] [PATCH 1/2] Makefile: Use -fno-strict-aliasing globally In-Reply-To: References: <1537162529-11113-1-git-send-email-bmeng.cn@gmail.com> Message-ID: <20180920132552.GD21228@opus> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de On Thu, Sep 20, 2018 at 11:37:36AM +0800, Bin Meng wrote: > Hi Tom, > > On Mon, Sep 17, 2018 at 1:30 PM Bin Meng wrote: > > > > The -fstrict-aliasing option is implicitly enabled at levels -O2, > > -O3, -Os by GCC. This option allows the compiler to assume the > > strictest aliasing rules applicable to the language being compiled. > > For example, the practice of reading from a different union member > > than the one most recently written to (called "type-punning") is > > common. In this case, "type-punning" only works if the memory is > > accessed through the union type, but might not work by taking the > > address, casting the resulting pointer and dereferencing the result, > > which is an undefined behavior per the "strict aliasing rules". > > > > GCC's -Wstrict-aliasing (included in -Wall) option does not catch > > all cases, but does attempt to catch the more common pitfalls. So > > there are cases that GCC does not report but the codes are violating > > the "strict aliasing rules". > > > > Given lots of codes that may be written to rely on "type-punning", > > and Linux kernel disables it by -fno-strict-aliasing globally, since > > U-Boot currently does this on nds32/riscv/x86 builds only, extend > > this for all architecture builds. > > > > Signed-off-by: Bin Meng > > Reviewed-by: Tom Rini > > Reviewed-by: Simon Glass > > --- > > > > Makefile | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > When will this series be applied? Another risc-v series has conflicts > in [PATCH 2/2] and if this is applied in mainline, I can respin my > risc-v series on top of this to save some time for Rick's handle it > himself. I will try and get to this soon, thanks for your patience. -- Tom -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 819 bytes Desc: not available URL: