Rollup merge of #128206 - bjorn3:import_lib_writing_refactor, r=jieyouxu

Make create_dll_import_lib easier to implement

This will make it easier to implement raw-dylib support in cg_clif and cg_gcc. This PR doesn't yet include an create_dll_import_lib implementation for cg_clif as I need to correctly implement dllimport in cg_clif first before raw-dylib can work at all with cg_clif.

Required for https://github.com/rust-lang/rustc_codegen_cranelift/issues/1345

2 files changed, 196 insertions, 37 deletions

diff --git a/compiler/rustc_codegen_ssa/src/back/archive.rs b/compiler/rustc_codegen_ssa/src/back/archive.rs
index 4f93b7b23c6..ce55d99f506 100644
--- a/compiler/rustc_codegen_ssa/src/back/archive.rs
+++ b/compiler/rustc_codegen_ssa/src/back/archive.rs
@@ -1,4 +1,6 @@
+use std::env;
 use std::error::Error;
+use std::ffi::OsString;
 use std::fs::{self, File};
 use std::io::{self, Write};
 use std::path::{Path, PathBuf};
@@ -9,7 +11,6 @@ use object::read::archive::ArchiveFile;
 use object::read::macho::FatArch;
 use rustc_data_structures::fx::FxIndexSet;
 use rustc_data_structures::memmap::Mmap;
-use rustc_session::cstore::DllImport;
 use rustc_session::Session;
 use rustc_span::symbol::Symbol;
 use tempfile::Builder as TempFileBuilder;
@@ -17,6 +18,7 @@ use tempfile::Builder as TempFileBuilder;
 use super::metadata::search_for_section;
 // Re-exporting for rustc_codegen_llvm::back::archive
 pub use crate::errors::{ArchiveBuildFailure, ExtractBundledLibsError, UnknownArchiveKind};
+use crate::errors::{DlltoolFailImportLibrary, ErrorCallingDllTool, ErrorWritingDEFFile};
 
 pub trait ArchiveBuilderBuilder {
     fn new_archive_builder<'a>(&self, sess: &'a Session) -> Box<dyn ArchiveBuilder + 'a>;
@@ -30,10 +32,9 @@ pub trait ArchiveBuilderBuilder {
         &self,
         sess: &Session,
         lib_name: &str,
-        dll_imports: &[DllImport],
-        tmpdir: &Path,
-        is_direct_dependency: bool,
-    ) -> PathBuf;
+        import_name_and_ordinal_vector: Vec<(String, Option<u16>)>,
+        output_path: &Path,
+    );
 
     fn extract_bundled_libs<'a>(
         &'a self,
@@ -72,6 +73,130 @@ pub trait ArchiveBuilderBuilder {
     }
 }
 
+pub fn create_mingw_dll_import_lib(
+    sess: &Session,
+    lib_name: &str,
+    import_name_and_ordinal_vector: Vec<(String, Option<u16>)>,
+    output_path: &Path,
+) {
+    let def_file_path = output_path.with_extension("def");
+
+    let def_file_content = format!(
+        "EXPORTS\n{}",
+        import_name_and_ordinal_vector
+            .into_iter()
+            .map(|(name, ordinal)| {
+                match ordinal {
+                    Some(n) => format!("{name} @{n} NONAME"),
+                    None => name,
+                }
+            })
+            .collect::<Vec<String>>()
+            .join("\n")
+    );
+
+    match std::fs::write(&def_file_path, def_file_content) {
+        Ok(_) => {}
+        Err(e) => {
+            sess.dcx().emit_fatal(ErrorWritingDEFFile { error: e });
+        }
+    };
+
+    // --no-leading-underscore: For the `import_name_type` feature to work, we need to be
+    // able to control the *exact* spelling of each of the symbols that are being imported:
+    // hence we don't want `dlltool` adding leading underscores automatically.
+    let dlltool = find_binutils_dlltool(sess);
+    let temp_prefix = {
+        let mut path = PathBuf::from(&output_path);
+        path.pop();
+        path.push(lib_name);
+        path
+    };
+    // dlltool target architecture args from:
+    // https://github.com/llvm/llvm-project-release-prs/blob/llvmorg-15.0.6/llvm/lib/ToolDrivers/llvm-dlltool/DlltoolDriver.cpp#L69
+    let (dlltool_target_arch, dlltool_target_bitness) = match sess.target.arch.as_ref() {
+        "x86_64" => ("i386:x86-64", "--64"),
+        "x86" => ("i386", "--32"),
+        "aarch64" => ("arm64", "--64"),
+        "arm" => ("arm", "--32"),
+        _ => panic!("unsupported arch {}", sess.target.arch),
+    };
+    let mut dlltool_cmd = std::process::Command::new(&dlltool);
+    dlltool_cmd
+        .arg("-d")
+        .arg(def_file_path)
+        .arg("-D")
+        .arg(lib_name)
+        .arg("-l")
+        .arg(&output_path)
+        .arg("-m")
+        .arg(dlltool_target_arch)
+        .arg("-f")
+        .arg(dlltool_target_bitness)
+        .arg("--no-leading-underscore")
+        .arg("--temp-prefix")
+        .arg(temp_prefix);
+
+    match dlltool_cmd.output() {
+        Err(e) => {
+            sess.dcx().emit_fatal(ErrorCallingDllTool {
+                dlltool_path: dlltool.to_string_lossy(),
+                error: e,
+            });
+        }
+        // dlltool returns '0' on failure, so check for error output instead.
+        Ok(output) if !output.stderr.is_empty() => {
+            sess.dcx().emit_fatal(DlltoolFailImportLibrary {
+                dlltool_path: dlltool.to_string_lossy(),
+                dlltool_args: dlltool_cmd
+                    .get_args()
+                    .map(|arg| arg.to_string_lossy())
+                    .collect::<Vec<_>>()
+                    .join(" "),
+                stdout: String::from_utf8_lossy(&output.stdout),
+                stderr: String::from_utf8_lossy(&output.stderr),
+            })
+        }
+        _ => {}
+    }
+}
+
+fn find_binutils_dlltool(sess: &Session) -> OsString {
+    assert!(sess.target.options.is_like_windows && !sess.target.options.is_like_msvc);
+    if let Some(dlltool_path) = &sess.opts.cg.dlltool {
+        return dlltool_path.clone().into_os_string();
+    }
+
+    let tool_name: OsString = if sess.host.options.is_like_windows {
+        // If we're compiling on Windows, always use "dlltool.exe".
+        "dlltool.exe"
+    } else {
+        // On other platforms, use the architecture-specific name.
+        match sess.target.arch.as_ref() {
+            "x86_64" => "x86_64-w64-mingw32-dlltool",
+            "x86" => "i686-w64-mingw32-dlltool",
+            "aarch64" => "aarch64-w64-mingw32-dlltool",
+
+            // For non-standard architectures (e.g., aarch32) fallback to "dlltool".
+            _ => "dlltool",
+        }
+    }
+    .into();
+
+    // NOTE: it's not clear how useful it is to explicitly search PATH.
+    for dir in env::split_paths(&env::var_os("PATH").unwrap_or_default()) {
+        let full_path = dir.join(&tool_name);
+        if full_path.is_file() {
+            return full_path.into_os_string();
+        }
+    }
+
+    // The user didn't specify the location of the dlltool binary, and we weren't able
+    // to find the appropriate one on the PATH. Just return the name of the tool
+    // and let the invocation fail with a hopefully useful error message.
+    tool_name
+}
+
 pub trait ArchiveBuilder {
     fn add_file(&mut self, path: &Path);
 
diff --git a/compiler/rustc_codegen_ssa/src/back/link.rs b/compiler/rustc_codegen_ssa/src/back/link.rs
index 653895380be..45a92fd03d5 100644
--- a/compiler/rustc_codegen_ssa/src/back/link.rs
+++ b/compiler/rustc_codegen_ssa/src/back/link.rs
@@ -51,7 +51,8 @@ use super::linker::{self, Linker};
 use super::metadata::{create_wrapper_file, MetadataPosition};
 use super::rpath::{self, RPathConfig};
 use crate::{
-    errors, looks_like_rust_object_file, CodegenResults, CompiledModule, CrateInfo, NativeLib,
+    common, errors, looks_like_rust_object_file, CodegenResults, CompiledModule, CrateInfo,
+    NativeLib,
 };
 
 pub fn ensure_removed(dcx: DiagCtxtHandle<'_>, path: &Path) {
@@ -390,17 +391,13 @@ fn link_rlib<'a>(
         }
     }
 
-    for (raw_dylib_name, raw_dylib_imports) in
-        collate_raw_dylibs(sess, codegen_results.crate_info.used_libraries.iter())?
-    {
-        let output_path = archive_builder_builder.create_dll_import_lib(
-            sess,
-            &raw_dylib_name,
-            &raw_dylib_imports,
-            tmpdir.as_ref(),
-            true,
-        );
-
+    for output_path in create_dll_import_libs(
+        sess,
+        archive_builder_builder,
+        codegen_results.crate_info.used_libraries.iter(),
+        tmpdir.as_ref(),
+        true,
+    )? {
         ab.add_archive(&output_path, Box::new(|_| false)).unwrap_or_else(|error| {
             sess.dcx().emit_fatal(errors::AddNativeLibrary { library_path: output_path, error });
         });
@@ -488,6 +485,47 @@ fn collate_raw_dylibs<'a>(
         .collect())
 }
 
+fn create_dll_import_libs<'a>(
+    sess: &Session,
+    archive_builder_builder: &dyn ArchiveBuilderBuilder,
+    used_libraries: impl IntoIterator<Item = &'a NativeLib>,
+    tmpdir: &Path,
+    is_direct_dependency: bool,
+) -> Result<Vec<PathBuf>, ErrorGuaranteed> {
+    Ok(collate_raw_dylibs(sess, used_libraries)?
+        .into_iter()
+        .map(|(raw_dylib_name, raw_dylib_imports)| {
+            let name_suffix = if is_direct_dependency { "_imports" } else { "_imports_indirect" };
+            let output_path = tmpdir.join(format!("{raw_dylib_name}{name_suffix}.lib"));
+
+            let mingw_gnu_toolchain = common::is_mingw_gnu_toolchain(&sess.target);
+
+            let import_name_and_ordinal_vector: Vec<(String, Option<u16>)> = raw_dylib_imports
+                .iter()
+                .map(|import: &DllImport| {
+                    if sess.target.arch == "x86" {
+                        (
+                            common::i686_decorated_name(import, mingw_gnu_toolchain, false),
+                            import.ordinal(),
+                        )
+                    } else {
+                        (import.name.to_string(), import.ordinal())
+                    }
+                })
+                .collect();
+
+            archive_builder_builder.create_dll_import_lib(
+                sess,
+                &raw_dylib_name,
+                import_name_and_ordinal_vector,
+                &output_path,
+            );
+
+            output_path
+        })
+        .collect())
+}
+
 /// Create a static archive.
 ///
 /// This is essentially the same thing as an rlib, but it also involves adding all of the upstream
@@ -2305,16 +2343,14 @@ fn linker_with_args(
     );
 
     // Link with the import library generated for any raw-dylib functions.
-    for (raw_dylib_name, raw_dylib_imports) in
-        collate_raw_dylibs(sess, codegen_results.crate_info.used_libraries.iter())?
-    {
-        cmd.add_object(&archive_builder_builder.create_dll_import_lib(
-            sess,
-            &raw_dylib_name,
-            &raw_dylib_imports,
-            tmpdir,
-            true,
-        ));
+    for output_path in create_dll_import_libs(
+        sess,
+        archive_builder_builder,
+        codegen_results.crate_info.used_libraries.iter(),
+        tmpdir,
+        true,
+    )? {
+        cmd.add_object(&output_path);
     }
     // As with add_upstream_native_libraries, we need to add the upstream raw-dylib symbols in case
     // they are used within inlined functions or instantiated generic functions. We do this *after*
@@ -2339,16 +2375,14 @@ fn linker_with_args(
         .flatten()
         .collect::<Vec<_>>();
     native_libraries_from_nonstatics.sort_unstable_by(|a, b| a.name.as_str().cmp(b.name.as_str()));
-    for (raw_dylib_name, raw_dylib_imports) in
-        collate_raw_dylibs(sess, native_libraries_from_nonstatics)?
-    {
-        cmd.add_object(&archive_builder_builder.create_dll_import_lib(
-            sess,
-            &raw_dylib_name,
-            &raw_dylib_imports,
-            tmpdir,
-            false,
-        ));
+    for output_path in create_dll_import_libs(
+        sess,
+        archive_builder_builder,
+        native_libraries_from_nonstatics,
+        tmpdir,
+        false,
+    )? {
+        cmd.add_object(&output_path);
     }
 
     // Library linking above uses some global state for things like `-Bstatic`/`-Bdynamic` to make