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loader.rs
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loader.rs
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//! Finds crate binaries and loads their metadata
import syntax::diagnostic::span_handler;
import syntax::{ast, attr};
import syntax::print::pprust;
import syntax::codemap::span;
import lib::llvm::{False, llvm, mk_object_file, mk_section_iter};
import filesearch::filesearch;
import io::writer_util;
export os;
export ctxt;
export load_library_crate;
export list_file_metadata;
export note_linkage_attrs;
export crate_name_from_metas;
export metadata_matches;
export meta_section_name;
enum os {
os_macos,
os_win32,
os_linux,
os_freebsd
}
type ctxt = {
diag: span_handler,
filesearch: filesearch,
span: span,
ident: ast::ident,
metas: ~[@ast::meta_item],
hash: str,
os: os,
static: bool
};
fn load_library_crate(cx: ctxt) -> {ident: str, data: @~[u8]} {
alt find_library_crate(cx) {
some(t) { ret t; }
none {
cx.diag.span_fatal(
cx.span, #fmt["can't find crate for '%s'", *cx.ident]);
}
}
}
fn find_library_crate(cx: ctxt) -> option<{ident: str, data: @~[u8]}> {
attr::require_unique_names(cx.diag, cx.metas);
find_library_crate_aux(cx, libname(cx), cx.filesearch)
}
fn libname(cx: ctxt) -> {prefix: str, suffix: str} {
if cx.static { ret {prefix: "lib", suffix: ".rlib"}; }
alt cx.os {
os_win32 { ret {prefix: "", suffix: ".dll"}; }
os_macos { ret {prefix: "lib", suffix: ".dylib"}; }
os_linux { ret {prefix: "lib", suffix: ".so"}; }
os_freebsd { ret {prefix: "lib", suffix: ".so"}; }
}
}
fn find_library_crate_aux(cx: ctxt,
nn: {prefix: str, suffix: str},
filesearch: filesearch::filesearch) ->
option<{ident: str, data: @~[u8]}> {
let crate_name = crate_name_from_metas(cx.metas);
let prefix: str = nn.prefix + *crate_name + "-";
let suffix: str = nn.suffix;
let mut matches = ~[];
filesearch::search(filesearch, |path| {
#debug("inspecting file %s", path);
let f: str = path::basename(path);
if !(str::starts_with(f, prefix) && str::ends_with(f, suffix)) {
#debug("skipping %s, doesn't look like %s*%s", path, prefix,
suffix);
option::none::<()>
} else {
#debug("%s is a candidate", path);
alt get_metadata_section(cx.os, path) {
option::some(cvec) {
if !crate_matches(cvec, cx.metas, cx.hash) {
#debug("skipping %s, metadata doesn't match", path);
option::none::<()>
} else {
#debug("found %s with matching metadata", path);
vec::push(matches, {ident: path, data: cvec});
option::none::<()>
}
}
_ {
#debug("could not load metadata for %s", path);
option::none::<()>
}
}
}
});
if matches.is_empty() {
none
} else if matches.len() == 1u {
some(matches[0])
} else {
cx.diag.span_err(
cx.span, #fmt("multiple matching crates for `%s`", *crate_name));
cx.diag.handler().note("candidates:");
for matches.each |match| {
cx.diag.handler().note(#fmt("path: %s", match.ident));
let attrs = decoder::get_crate_attributes(match.data);
note_linkage_attrs(cx.diag, attrs);
}
cx.diag.handler().abort_if_errors();
none
}
}
fn crate_name_from_metas(metas: ~[@ast::meta_item]) -> @str {
let name_items = attr::find_meta_items_by_name(metas, "name");
alt vec::last_opt(name_items) {
some(i) {
alt attr::get_meta_item_value_str(i) {
some(n) { n }
// FIXME (#2406): Probably want a warning here since the user
// is using the wrong type of meta item.
_ { fail }
}
}
none { fail "expected to find the crate name" }
}
}
fn note_linkage_attrs(diag: span_handler, attrs: ~[ast::attribute]) {
for attr::find_linkage_attrs(attrs).each |attr| {
diag.handler().note(#fmt("meta: %s", pprust::attr_to_str(attr)));
}
}
fn crate_matches(crate_data: @~[u8], metas: ~[@ast::meta_item],
hash: str) -> bool {
let attrs = decoder::get_crate_attributes(crate_data);
let linkage_metas = attr::find_linkage_metas(attrs);
if hash.is_not_empty() {
let chash = decoder::get_crate_hash(crate_data);
if *chash != hash { ret false; }
}
metadata_matches(linkage_metas, metas)
}
fn metadata_matches(extern_metas: ~[@ast::meta_item],
local_metas: ~[@ast::meta_item]) -> bool {
#debug("matching %u metadata requirements against %u items",
vec::len(local_metas), vec::len(extern_metas));
#debug("crate metadata:");
for extern_metas.each |have| {
#debug(" %s", pprust::meta_item_to_str(*have));
}
for local_metas.each |needed| {
#debug("looking for %s", pprust::meta_item_to_str(*needed));
if !attr::contains(extern_metas, needed) {
#debug("missing %s", pprust::meta_item_to_str(*needed));
ret false;
}
}
ret true;
}
fn get_metadata_section(os: os,
filename: str) -> option<@~[u8]> unsafe {
let mb = str::as_c_str(filename, |buf| {
llvm::LLVMRustCreateMemoryBufferWithContentsOfFile(buf)
});
if mb as int == 0 { ret option::none::<@~[u8]>; }
let of = alt mk_object_file(mb) {
option::some(of) { of }
_ { ret option::none::<@~[u8]>; }
};
let si = mk_section_iter(of.llof);
while llvm::LLVMIsSectionIteratorAtEnd(of.llof, si.llsi) == False {
let name_buf = llvm::LLVMGetSectionName(si.llsi);
let name = unsafe { str::unsafe::from_c_str(name_buf) };
if str::eq(name, meta_section_name(os)) {
let cbuf = llvm::LLVMGetSectionContents(si.llsi);
let csz = llvm::LLVMGetSectionSize(si.llsi) as uint;
unsafe {
let cvbuf: *u8 = unsafe::reinterpret_cast(cbuf);
ret some(@vec::unsafe::from_buf(cvbuf, csz));
}
}
llvm::LLVMMoveToNextSection(si.llsi);
}
ret option::none::<@~[u8]>;
}
fn meta_section_name(os: os) -> str {
alt os {
os_macos { "__DATA,__note.rustc" }
os_win32 { ".note.rustc" }
os_linux { ".note.rustc" }
os_freebsd { ".note.rustc" }
}
}
// A diagnostic function for dumping crate metadata to an output stream
fn list_file_metadata(os: os, path: str, out: io::writer) {
alt get_metadata_section(os, path) {
option::some(bytes) { decoder::list_crate_metadata(bytes, out); }
option::none {
out.write_str("could not find metadata in " + path + ".\n");
}
}
}