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cmd/link: silently performs incorrect relocations when linking foreign objects #24321
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Can you show us a self-contained example? Does it work if you use Perhaps we should default to external linking mode in the presence of any syso files. |
Timed out in state WaitingForInfo. Closing. (I am just a bot, though. Please speak up if this is a mistake or you have the requested information.) |
Reopening, I can provide a test case from FiloSottile/ed25519-dalek-rustgo#1. |
Removing the WaitingForInfo tag worked around GopherBot fighting you :P. |
@ianlancetaylor I encountered this issue while looking into #30890. Also, whilst typing in my issue number I discovered the very next issue filed was also about relocations - interesting/amusing coincidence: #30891. .text
.file "-"
.globl exampleFunc # -- Begin function exampleFunc
.p2align 4, 0x90
.type exampleFunc,@function
exampleFunc: # @exampleFunc
.Lfunc_begin0:
.cfi_startproc
movzbl .L__const.exampleFunc.one(%rip), %eax
movl %eax, 8(%rsp)
retq
.Lfunc_end0:
.size exampleFunc, .Lfunc_end0-exampleFunc
.cfi_endproc
.type .L__const.exampleFunc.one,@object # @__const.exampleFunc.one
.section .rodata.cst4,"aM",@progbits,4
.p2align 2
.L__const.exampleFunc.one:
.long 1 # 0x1
.size .L__const.exampleFunc.one, 4 If I build this with
but it's missing in the go binary:
|
So far as I can tell the reason this fails is something to do with the cross linking between the
and try to compile that to a What this This fixup isn't needed for external linking because that leverages the |
(I should say I've been trying to get to the bottom of https://bugzilla.kernel.org/show_bug.cgi?id=216610 and |
It took me a while to figure out why optimized C compilation seemed to generate miscomputation of the Fibonacci number sequence. It appears to be an unresolved issue with Go's internal linking which is discussed here: golang/go#24321 For a compute kernel, it seems important to be able to accommodate compiler optimization. This adds some refinement for the strategy I'm exploring to address: https://bugzilla.kernel.org/show_bug.cgi?id=216610 Signed-off-by: Andrew G. Morgan <morgan@kernel.org>
For example, when linking syso files.
Adding
go:cgo_import_dynamic
helps but (1) it was recently disabled for security reasons for non-cgo files, then reenabled because solaris needs it, so it's unclear if this policy will persist in the long-run for all architectures, and (2) you need to specify it for specific symbols rather than for all symbols. In any case, an error should be raised with a hint on what to do, rather than succeeding silently with invalid output.The equivalent thing in Haskell Just Works with no extra annotations.
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