[SR-4727] Inline asm error when building swift_overlay.o on aarch64

[swift-ci]

Previous ID	SR-4727
Radar	None
Original Reporter	helge (JIRA User)
Type	Bug
Status	Resolved
Resolution	Done

Attachment: Download

Environment

uname -a
Linux scw-66d779 4.9.23-std-1 #1 SMP Mon Apr 24 13:18:14 UTC 2017 aarch64 aarch64 aarch64 GNU/Linux
cat /etc/lsb-release
DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=16.04
DISTRIB_CODENAME=xenial
DISTRIB_DESCRIPTION="Ubuntu 16.04.2 LTS"
cat /proc/cpuinfo
processor : 0
BogoMIPS : 200.00
Features : fp asimd evtstrm aes pmull sha1 sha2 crc32 atomics
CPU implementer : 0x43
CPU architecture: 8
CPU variant : 0x1
CPU part : 0x0a1
CPU revision : 1
...

Additional Detail from JIRA

Votes	0
Component/s
Labels	Bug, arm, armv8
Assignee	None
Priority	Medium

md5: 92fb892c95274f8eb937f0f16d918d0b

Issue Description:

I'm trying to build Swift 3.1.1 on a Scaleway ARMv8 instance. Hacking around SR-4726, libdispatch fails next on me when building the `swift_overlay.o`:

/swiftsrc/swift-corelibs-libdispatch/src/swift/Dispatch.swift:99:4: warning: default will never be executed
                        default: return nil
                        ^
<inline asm>:1:27: error: unexpected token in argument list
        mov     fp, fp          ; marker for objc_retainAutoreleaseReturnValue
                                             ^
LLVM ERROR: Error parsing inline asm

Makefile:998: recipe for target '/swiftsrc/build/buildbot_linux/libdispatch-linux-aarch64/src/swift/swift_overlay.o' failed

[belkadan]

Hm, what compiler is being used to build here? Can you get it to build with Clang?

[belkadan]

Or is it using the just-built Clang?

[swift-ci]

Comment by Helge Heß (JIRA)

Just look at the build log I attached:

/swiftsrc/build/buildbot_linux/llvm-linux-aarch64/bin/clang

The particular error comes from the clang build as part of the swift build. And the system compiler is clang-3.8, as that is the version which seems to work w/ Swift on ARM.

Here is the build script:

https://github.com/helje5/dockSwiftOnARM/blob/master/empty-ctx/build-3.1.1.sh#L51

[belkadan]

Oops, sorry, thanks.

[swift-ci]

Comment by David Grove (JIRA)

I don't think this is really a libdispatch issue. It looks to me like the problematic asm directive is most likely being generated by configureARM64 in SwiftTargetInfo.cpp.

[compnerd]

I think that this was fixed a long time ago in clang. The marker is the autorelease elision marker.