add more crates

Signed-off-by: xermicus <cyrill@parity.io>

crates/lld-sys/Cargo.toml

@@ -0,0 +1,14 @@
+[package]
+name = "lld-sys"
+version = "0.1.0"
+edition = "2021"
+build = "build.rs"
+
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+libc = { workspace = true }
+
+[build-dependencies]
+cc = { workspace = true }

crates/lld-sys/build.rs

@@ -0,0 +1,25 @@
+// SPDX-License-Identifier: Apache-2.0
+
+use std::{io::Read, process::Command};
+
+fn main() {
+    let mut flags = String::new();
+    Command::new("llvm-config")
+        .args(["--cxxflags"])
+        .output()
+        .expect("llvm-config should be able to provide CXX flags")
+        .stdout
+        .as_slice()
+        .read_to_string(&mut flags)
+        .expect("llvm-config output should be utf8");
+
+    let mut builder = cc::Build::new();
+    flags
+        .split_whitespace()
+        .fold(&mut builder, |builder, flag| builder.flag(flag))
+        .cpp(true)
+        .file("src/linker.cpp")
+        .compile("liblinker.a");
+
+    println!("cargo:rerun-if-changed=build.rs");
+}

crates/lld-sys/src/lib.rs

@@ -0,0 +1,3 @@
+extern "C" {
+    pub fn LLDELFLink(args: *const *const libc::c_char, size: libc::size_t) -> libc::c_int;
+}

crates/lld-sys/src/linker.cpp

@@ -0,0 +1,22 @@
+// SPDX-License-Identifier: Apache-2.0
+
+#include "lld/Common/Driver.h"
+#include "lld/Common/CommonLinkerContext.h"
+#include "llvm/Support/CrashRecoveryContext.h"
+
+extern "C" bool LLDELFLink(const char *argv[], size_t length)
+{
+    bool canRunAgain;
+
+    {
+        llvm::ArrayRef<const char *> args(argv, length);
+        llvm::CrashRecoveryContext crc;
+        if (!crc.RunSafely([&]()
+                           { canRunAgain = lld::elf::link(args, llvm::outs(), llvm::errs(), false, false); }))
+            return false;
+    }
+
+    llvm::CrashRecoveryContext crc;
+    return canRunAgain && crc.RunSafely([&]()
+                                        { lld::CommonLinkerContext::destroy(); });
+}