Segfault when building with self-hosted x86_64 backend

[plzfgme]

Zig Version

0.15.2

Steps to Reproduce and Observed Behavior

The build failed silently.

dmesg shows:

lldb:

build.zig

const std = @import("std");

pub fn build(b: *std.Build) void {
    const target = b.standardTargetOptions(.{});
    const optimize = b.standardOptimizeOption(.{});

    const hello = b.addObject(.{
        .name = "hello",
        .root_module = b.createModule(.{
            .target = target,
            .optimize = optimize,
            .link_libcpp = true,
        }),
    });

    hello.root_module.addCSourceFiles(.{
        .files = &.{
            "foo.cpp",
            "bar.cpp",
        },
    });
    hello.root_module.addIncludePath(.{
        .cwd_relative = ".",
    });

    const exe = b.addExecutable(.{
        .name = "lca",
        .root_module = b.createModule(.{
            .root_source_file = b.path("main.zig"),
            .target = target,
            .optimize = optimize,
            .link_libcpp = true,
            .imports = &.{},
        }),
        // .use_llvm = true,
    });

    exe.root_module.addObject(hello);
    exe.root_module.addIncludePath(.{
        .cwd_relative = ".",
    });
    b.installArtifact(exe);
}

foo.cpp

#include "foo.h"
#include <string>
#include <vector>

void foo() { std::vector<std::string> keys{"xxx", "yyy"}; }

foo.h

#ifndef _FOO_H_
#define _FOO_H_

#ifdef __cplusplus
extern "C" {
#endif

void foo();

#ifdef __cplusplus
}
#endif

#endif

bar.cpp (similar to foo.cpp)

#include "bar.h"
#include <string>
#include <vector>

void bar() { std::vector<std::string> keys{"xxx", "yyy"}; }

bar.h

#ifndef _BAR_H_
#define _BAR_H_

#ifdef __cplusplus
extern "C" {
#endif

void bar();

#ifdef __cplusplus
}
#endif

#endif

main.zig

const std = @import("std");

pub fn main() void {
    std.debug.print("Hello, World!\n", .{});
}

Using .use_llvm=true or removing one of foo.cpp and bar.cpp from build.zig can fix this.

Expected Behavior

No error

[WGrav01]

I can reproduce this.