cmd/link: clang on windows fatal error LNK1104: cannot open file 'mingwex.lib'

[voltagex]

Seems to be similar to #16932

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

$ go version
go version go1.20.4 windows/amd64

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
```
```
set GO111MODULE=
set GOARCH=amd64
set GOBIN=
set GOCACHE=C:\Users\Adam\AppData\Local\go-build
set GOENV=C:\Users\Adam\AppData\Roaming\go\env
set GOEXE=.exe
set GOEXPERIMENT=
set GOFLAGS=
set GOHOSTARCH=amd64
set GOHOSTOS=windows
set GOINSECURE=
set GOMODCACHE=C:\Users\Adam\go\pkg\mod
set GONOPROXY=
set GONOSUMDB=
set GOOS=windows
set GOPATH=C:\Users\Adam\go
set GOPRIVATE=
set GOPROXY=https://proxy.golang.org,direct
set GOROOT=C:\Program Files\Go
set GOSUMDB=sum.golang.org
set GOTMPDIR=
set GOTOOLDIR=C:\Program Files\Go\pkg\tool\windows_amd64
set GOVCS=
set GOVERSION=go1.20.4
set GCCGO=gccgo
set GOAMD64=v1
set AR=ar
set CC=clang
set CXX=g++
set CGO_ENABLED=1
set GOMOD=C:\git\golinkerbug\go.mod
set GOWORK=
set CGO_CFLAGS=-fuse-ld=lld
set CGO_CPPFLAGS=
set CGO_CXXFLAGS=-O2 -g
set CGO_FFLAGS=-O2 -g
set CGO_LDFLAGS=-O2 -g
set PKG_CONFIG=pkg-config
set GOGCCFLAGS=-m64 -mthreads -fno-caret-diagnostics -Qunused-arguments -fmessage-length=0 -fdebug-prefix-map=C:\Users\Adam\AppData\Local\Temp\go-build290096245=/tmp/go-build -gno-record-gcc-switches

What did you do?

package main

import (
	"database/sql"
	"fmt"

	_ "github.com/mattn/go-sqlite3"
)

func main() {
	db, err := sql.Open("sqlite3", "./foo.db")
	if err != nil {
		panic(err)
	}

	fmt.Printf("%v+", db)
}

1. Installed clang via the Visual Studio 2022 installer
2. Opened a VS 2022 Developer Powershell
3. $env:CGO_ENABLED=1
4. $env:CC="clang"
5. go build

(I also tried $env:CGO_CFLAGS="-fuse-ld=lld" and $env:CFLAGS="-fuse-ld=lld" with the same result)

What did you expect to see?

Program built successfully.

What did you see instead?

PS C:\git\golinkerbug> go build
# golinkerbug
C:\Program Files\Go\pkg\tool\windows_amd64\link.exe: running clang failed: exit status 1104
LINK : warning LNK4044: unrecognized option '/-tsaware'; ignored
LINK : warning LNK4044: unrecognized option '/-nxcompat'; ignored
LINK : warning LNK4044: unrecognized option '/-major-os-version=6'; ignored
LINK : warning LNK4044: unrecognized option '/-minor-os-version=1'; ignored
LINK : warning LNK4044: unrecognized option '/-major-subsystem-version=6'; ignored
LINK : warning LNK4044: unrecognized option '/-minor-subsystem-version=1'; ignored
LINK : warning LNK4044: unrecognized option '/-dynamicbase'; ignored
LINK : warning LNK4044: unrecognized option '/-high-entropy-va'; ignored
LINK : warning LNK4044: unrecognized option '/T'; ignored
LINK : warning LNK4044: unrecognized option '/-start-group'; ignored
LINK : warning LNK4044: unrecognized option '/-end-group'; ignored
LINK : fatal error LNK1104: cannot open file 'mingwex.lib'
clang: error: linker command failed with exit code 1104 (use -v to see invocation)

[bcmills]

What version of Clang are you using?
(CC @golang/windows)

[voltagex]

@bcmills

clang -v
clang version 15.0.1
Target: i686-pc-windows-msvc
Thread model: posix
InstalledDir: C:\Program Files\Microsoft Visual Studio\2022\Community\VC\Tools\Llvm\bin

[voltagex]

Unfortunately this looks like a dupe of #17014

[qmuntal]

Unfortunately this looks like a dupe of #17014

It is. Direct use of clang is not supported yet, although that can bridge this gap, i.e. https://github.com/mstorsjo/llvm-mingw. In fact that toolchain is being used by the windows/arm64 builders right now.

[voltagex]

@qmuntal is clang/msvc support planned at all?

[qmuntal]

@qmuntal is clang/msvc support planned at all?

I'll love that to happen. #17014 is labeled as help wanted and needs fix, so Go will support clang on Windows when someone has the time to implement it.