Murray Campbell
Hi,
I am trying to help solve #9125 in which an ARM build creates binaries that mangle Float values.
After a great deal of help from rwbarton (detailed in the comments) it would appear that the problem is actually in LLVM 3.0. (v3.0 is virtually insisted upon in the iOS build instructions)
Building GHC 7.8.3 for the iOS simulator with LLVM 3.4 produces a compiler that creates well behaved binaries.
Unfortunately, building the device version fails with several warnings along the lines of:
/var/folders/02/0mv6cz6505x2xhzlr279k2340000gp/T/ghc5244_0/ghc5244_6-armv7s.s:2944:2: warning: deprecated since v7, use 'dmb' mcr p15, #0, r7, c7, c10, #5
and:
libraries/ghc-prim/cbits/popcnt.c:76:38: warning: shift count >= width of type [-Wshift-count-overflow] popcount_tab[(unsigned char)(x >> 32)] + ^ ~~ This is a case of an #ifdef being inappropriately x86 specific. The 32-bit popcnt implementation should be used on ARM yet the #ifdef looks at i386_HOST_ARCH.
before bailing with
/var/folders/02/0mv6cz6505x2xhzlr279k2340000gp/T/ghc6860_0/ghc6860_6-armv7.s:3916:2: error: out of range pc-relative fixup value vldr d8, LCPI70_0 ^
/var/folders/02/0mv6cz6505x2xhzlr279k2340000gp/T/ghc6860_0/ghc6860_6-armv7s.s:3916:2: error: out of range pc-relative fixup value vldr d8, LCPI70_0 ^
Next I tried to build HEAD (plus phabricator D208) with LLVM 3.4 but got the same error.
I've never seen an error of this form. What symbol definitions does this error occur in?
Various adventures with LLVM 3.5 ended with the same error.
Be aware that LLVM 3.5 will require D155 due to changes in where LLVM aliases are accepted. Cheers, - Ben