cmd/internal/objabi, cmd/link: direct calls not correctly identified on riscv64

[zhsj]

What version of Go are you using (go version)?

$ go version
go version go1.21.0 linux/riscv64

Does this issue reproduce with the latest release?

Yes.

What operating system and processor architecture are you using (go env)?

go env Output

$ go env
GO111MODULE=''
GOARCH='riscv64'
GOBIN=''
GOCACHE='/root/.cache/go-build'
GOENV='/root/.config/go/env'
GOEXE=''
GOEXPERIMENT=''
GOFLAGS=''
GOHOSTARCH='riscv64'
GOHOSTOS='linux'
GOINSECURE=''
GOMODCACHE='/root/go/pkg/mod'
GONOPROXY=''
GONOSUMDB=''
GOOS='linux'
GOPATH='/root/go'
GOPRIVATE=''
GOPROXY='https://goproxy.cn'
GOROOT='/usr/lib/go-1.21'
GOSUMDB='sum.golang.org'
GOTMPDIR=''
GOTOOLCHAIN='auto'
GOTOOLDIR='/usr/lib/go-1.21/pkg/tool/linux_riscv64'
GOVCS=''
GOVERSION='go1.21.0'
GCCGO='gccgo'
AR='ar'
CC='gcc'
CXX='g++'
CGO_ENABLED='1'
GOMOD='/work/go.mod'
GOWORK=''
CGO_CFLAGS='-O2 -g'
CGO_CPPFLAGS=''
CGO_CXXFLAGS='-O2 -g'
CGO_FFLAGS='-O2 -g'
CGO_LDFLAGS='-O2 -g'
PKG_CONFIG='pkg-config'
GOGCCFLAGS='-fPIC -pthread -Wl,--no-gc-sections -fmessage-length=0 -ffile-prefix-map=/tmp/go-build2926220559=/tmp/go-build -gno-record-gcc-switches'

What did you do?

root@bfe27bbaba29:/# git clone https://github.com/prometheus/alertmanager /work
root@bfe27bbaba29:/# cd /work
root@bfe27bbaba29:/work# go build ./cmd/amtool/

What did you expect to see?

Build successfully.

What did you see instead?

# github.com/prometheus/alertmanager/cmd/amtool
github.com/aws/aws-sdk-go/aws/endpoints.init: missing section for github.com/aws/aws-sdk-go/aws/endpoints.map.init.0
github.com/aws/aws-sdk-go/aws/endpoints.init: reloc 62 (R_RISCV_PCREL_ITYPE) to non-elf symbol github.com/aws/aws-sdk-go/aws/endpoints.map.init.0 (outer=github.com/aws/aws-sdk-go/aws/endpoints.map.init.0) 1 (STEXT)
github.com/aws/aws-sdk-go/aws/endpoints.init: unreachable reloc 62 (R_RISCV_PCREL_ITYPE) target github.com/aws/aws-sdk-go/aws/endpoints.map.init.0

[cherrymui]

cc @golang/riscv64 @golang/compiler

[cherrymui]

Is this a regression in Go 1.21? Does it build with Go 1.20? Thanks.

[zhsj]

Is this a regression in Go 1.21? Does it build with Go 1.20? Thanks.

Yes. Go1.20 can build.

[mengzhuo]

I can confirm this issue, bisect shows d49719b is the first bad commit.

cc @randall77

[mknyszek]

In triage, we think the linker failure is a red herring and that it's actually an issue with the write barrier on RISC-V. The problem is we can't really make progress without a RISC-V machine to access (we have a builder, but we don't have SSH privileges). @randall77 briefly looked into this, but got stuck there.

While we look for a way to access a machine in the background, it would be really helpful if someone from @golang/riscv64 could continue investigation here with these breadcrumbs. Thanks.

[mengzhuo]

Feel free send me mzh <at> golangcn.org the ssh public key if you want to login builder unmatched025.farm.rvlab.org.

[mengzhuo]

Some updates, I can build this amtool now but can't start it

panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x0 pc=0x0]

goroutine 1 [running]:
github.com/aws/aws-sdk-go/aws/endpoints.init()
        /root/go/pkg/mod/github.com/aws/aws-sdk-go@v1.44.317/aws/endpoints/defaults.go:41015 +0x90

I found that defautls.go has an abnormal big initial function (952KB), both PC and link failure might related to big init function.