+// Copyright 2017 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+use rustc::util::common;
+use rustc::middle::cstore::MetadataLoader;
+use rustc_back::target::Target;
+use llvm;
+use llvm::{False, ObjectFile, mk_section_iter};
+use llvm::archive_ro::ArchiveRO;
+
+use owning_ref::{ErasedBoxRef, OwningRef};
+use std::path::Path;
+use std::ptr;
+use std::slice;
+
+pub const METADATA_FILENAME: &str = "rust.metadata.bin";
+
+pub struct LlvmMetadataLoader;
+
+impl MetadataLoader for LlvmMetadataLoader {
+ fn get_rlib_metadata(&self, _: &Target, filename: &Path) -> Result<ErasedBoxRef<[u8]>, String> {
+ // Use ArchiveRO for speed here, it's backed by LLVM and uses mmap
+ // internally to read the file. We also avoid even using a memcpy by
+ // just keeping the archive along while the metadata is in use.
+ let archive = ArchiveRO::open(filename)
+ .map(|ar| OwningRef::new(box ar))
+ .ok_or_else(|| {
+ debug!("llvm didn't like `{}`", filename.display());
+ format!("failed to read rlib metadata: '{}'", filename.display())
+ })?;
+ let buf: OwningRef<_, [u8]> = archive
+ .try_map(|ar| {
+ ar.iter()
+ .filter_map(|s| s.ok())
+ .find(|sect| sect.name() == Some(METADATA_FILENAME))
+ .map(|s| s.data())
+ .ok_or_else(|| {
+ debug!("didn't find '{}' in the archive", METADATA_FILENAME);
+ format!("failed to read rlib metadata: '{}'",
+ filename.display())
+ })
+ })?;
+ Ok(buf.erase_owner())
+ }
+
+ fn get_dylib_metadata(&self,
+ target: &Target,
+ filename: &Path)
+ -> Result<ErasedBoxRef<[u8]>, String> {
+ unsafe {
+ let buf = common::path2cstr(filename);
+ let mb = llvm::LLVMRustCreateMemoryBufferWithContentsOfFile(buf.as_ptr());
+ if mb as isize == 0 {
+ return Err(format!("error reading library: '{}'", filename.display()));
+ }
+ let of = ObjectFile::new(mb)
+ .map(|of| OwningRef::new(box of))
+ .ok_or_else(|| format!("provided path not an object file: '{}'",
+ filename.display()))?;
+ let buf = of.try_map(|of| search_meta_section(of, target, filename))?;
+ Ok(buf.erase_owner())
+ }
+ }
+}
+
+fn search_meta_section<'a>(of: &'a ObjectFile,
+ target: &Target,
+ filename: &Path)
+ -> Result<&'a [u8], String> {
+ unsafe {
+ let si = mk_section_iter(of.llof);
+ while llvm::LLVMIsSectionIteratorAtEnd(of.llof, si.llsi) == False {
+ let mut name_buf = ptr::null();
+ let name_len = llvm::LLVMRustGetSectionName(si.llsi, &mut name_buf);
+ let name = slice::from_raw_parts(name_buf as *const u8, name_len as usize).to_vec();
+ let name = String::from_utf8(name).unwrap();
+ debug!("get_metadata_section: name {}", name);
+ if read_metadata_section_name(target) == name {
+ let cbuf = llvm::LLVMGetSectionContents(si.llsi);
+ let csz = llvm::LLVMGetSectionSize(si.llsi) as usize;
+ // The buffer is valid while the object file is around
+ let buf: &'a [u8] = slice::from_raw_parts(cbuf as *const u8, csz);
+ return Ok(buf);
+ }
+ llvm::LLVMMoveToNextSection(si.llsi);
+ }
+ }
+ Err(format!("metadata not found: '{}'", filename.display()))
+}
+
+pub fn metadata_section_name(target: &Target) -> &'static str {
+ // Historical note:
+ //
+ // When using link.exe it was seen that the section name `.note.rustc`
+ // was getting shortened to `.note.ru`, and according to the PE and COFF
+ // specification:
+ //
+ // > Executable images do not use a string table and do not support
+ // > section names longer than 8 characters
+ //
+ // https://msdn.microsoft.com/en-us/library/windows/hardware/gg463119.aspx
+ //
+ // As a result, we choose a slightly shorter name! As to why
+ // `.note.rustc` works on MinGW, that's another good question...
+
+ if target.options.is_like_osx {
+ "__DATA,.rustc"
+ } else {
+ ".rustc"
+ }
+}
+
+fn read_metadata_section_name(_target: &Target) -> &'static str {
+ ".rustc"
+}