<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/85349>85349</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            Unresolved TPOFF64 in -static-pie when using lld
        </td>
    </tr>

    <tr>
      <th>Labels</th>
      <td>
            lld
      </td>
    </tr>

    <tr>
      <th>Assignees</th>
      <td>
      </td>
    </tr>

    <tr>
      <th>Reporter</th>
      <td>
          wc00862805aj
      </td>
    </tr>
</table>

<pre>
    Here is the `demo.go` file that I compiled:

```go
package main

// #cgo LDFLAGS: -ldl
// #include <stdlib.h>
// #include <dlfcn.h>
import "C"
import (
        "fmt"
)

func main() {
        fmt.Printf("This is a Go demo.\n")
        C.CString("libsystemd-login.so.0")
        return
}
```

When I compile it with the following command:
```shell
export CC=
go build -buildmode=pie -o demo-ld.exe -ldflags '-buildid=none -tmpdir=. -extldflags=-ftrapv -extldflags=-Wl,-z,relro,-z,now -linkmode=external -extldflags=-static-pie' demo.go;
```
`demo-ld` can be executed correctly. However, if I compile it with:
```shell
export CC=clang
go build -buildmode=pie -o demo-lld.exe -ldflags '-buildid=none -tmpdir=. -extldflags=-ftrapv -extldflags=-Wl,-z,relro,-z,now -linkmode=external -extldflags=-static-pie' demo.go;
```
`demo-lld` cannot be executed and ends with a "Segmentation fault (core dumped)" error.

Hence, I tried to use `readelf -r` on these files to identify the cause of the failure. I discovered that `demo-lld.exe` cannot resolve the TPOFF64 relocation type statically, while `demo-ld.exe` can. As a result, `demo-lld.exe` has several TPOFF64 entries in its dynamic relocation section. I also attempted to debug `demo-lld` with GDB and found that when the linker skips the resolution of TPOFF64, it can be executed correctly. However, if the resolution is performed, it fails at `dl_allocate_static_tls` due to uninitialized TLS, which does not occur with `demo-ld.exe`.


During my search on glibc, I came across an existing issue report (https://sourceware.org/bugzilla/show_bug.cgi?id=31302) that addresses this problem. According to their conclusion, `lld` should be able to resolve TPOFF64 relocations with -static-pie.
</pre>
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