Bug#1001314: mozjs78: FTBFS on armhf: '-mfloat-abi=hard': selected architecture lacks an FPU

[peter green]

On 08/12/2021 23:56, Simon McVittie wrote:
 > On Wed, 08 Dec 2021 at 20:11:55 +0000, peter green wrote:
 >> The default -march value on Debian armhf is "armv7-a+fp". You should
 >> *NOT* use "armv7-a+vfpv3" as that specifies the version of vfpv3
 >> with 32 double precision registers which is above the Debian baseline.
 >
 > https://github.com/alexcrichton/cc-rs/commit/b2f6b146b75299c444e05bbde50d03705c7c4b6e
 > (which I have now applied to the copy of cc-rs in mozjs78) uses
 > "-march=armv7-a -mfpu=vfpv3-d16", which seems like a plausible encoding of
 > the minimum spec given in https://wiki.debian.org/ArmHardFloatPort and
 > https://wiki.debian.org/ArchitectureSpecificsMemo#Architecture_baselines
 > (ARMv7 with Thumb-2 and VFPv3-D16).
Yes that is fine.

 >
 > If I understand correctly, VFPv3-D16 refers to the version of vfpv3 with
 > only 16 registers, which is exactly what our armhf baseline guarantees
 > (and as you point out, some ARM CPUs with VFPv3 have more registers, but we
 > require our binaries to assume those extra registers are not available).
 > Am I getting this right?
Yes.