mikros/rust
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

linker: Add more markup and comments to code producing linker arguments

Browse Source
This commit is contained in:
Vadim Petrochenkov 2020-04-05 18:10:55 +03:00
parent 7f42d81ea4
commit fd6fa686df
1 changed files with 61 additions and 23 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

84
src/librustc_codegen_ssa/back/link.rs
View File

@ -193,6 +193,7 @@ pub fn get_linker(sess: &Session, linker: &Path, flavor: LinkerFlavor) -> Comman
_ => None,
};
if let Some(ref a) = arch {
// FIXME: Move this to `fn linker_with_args`.
let mut arg = OsString::from("/LIBPATH:");
arg.push(format!("{}\\lib\\{}\\store", root_lib_path.display(), a.to_string()));
cmd.arg(&arg);
@ -1254,9 +1255,29 @@ fn add_post_link_args(cmd: &mut dyn Linker, sess: &'a Session, flavor: LinkerFla
}
}
/// Add sysroot and other globally set directories to the directory search list.
fn add_library_search_dirs(cmd: &mut dyn Linker, sess: &'a Session) {
// The default library location, we need this to find the runtime.
// The location of crates will be determined as needed.
let lib_path = sess.target_filesearch(PathKind::All).get_lib_path();
// prefer system mingw-w64 libs, see get_crt_libs_path comment for more details
if cfg!(windows) && sess.target.target.llvm_target.contains("windows-gnu") {
if let Some(compiler_libs_path) = get_crt_libs_path(sess) {
cmd.include_path(&compiler_libs_path);
}
}
cmd.include_path(&fix_windows_verbatim_for_gcc(&lib_path));
}
/// Produce the linker command line containing linker path and arguments.
/// `NO-OPT-OUT` marks the arguments that cannot be removed from the command line
/// by the user without creating a custom target specification.
/// `OBJECT-FILES` specify whether the arguments can add object files.
/// `CUSTOMIZATION-POINT` means that arbitrary arguments defined by the user
/// or by the target spec can be inserted here.
/// `AUDIT-ORDER` - need to figure out whether the option is order-dependent or not.
fn linker_with_args<'a, B: ArchiveBuilder<'a>>(
path: &Path,
flavor: LinkerFlavor,
@ -1273,9 +1294,10 @@ fn linker_with_args<'a, B: ArchiveBuilder<'a>>(
assert!(base_cmd.get_args().is_empty() || sess.target.target.target_vendor == "uwp");
let cmd = &mut *codegen_results.linker_info.to_linker(base_cmd, &sess, flavor, target_cpu);
// NO-OPT-OUT
// NO-OPT-OUT, OBJECT-FILES-MAYBE, CUSTOMIZATION-POINT
add_pre_link_args(cmd, sess, flavor, crate_type);
// NO-OPT-OUT, OBJECT-FILES-NO, AUDIT-ORDER
if sess.target.target.options.is_like_fuchsia {
let prefix = match sess.opts.debugging_opts.sanitizer {
Some(Sanitizer::Address) => "asan/",
@ -1284,9 +1306,10 @@ fn linker_with_args<'a, B: ArchiveBuilder<'a>>(
cmd.arg(format!("--dynamic-linker={}ld.so.1", prefix));
}
// NO-OPT-OUT
// NO-OPT-OUT, OBJECT-FILES-YES
add_pre_link_objects(cmd, sess, crate_type);
// NO-OPT-OUT, OBJECT-FILES-NO, AUDIT-ORDER
if sess.target.target.options.is_like_emscripten {
cmd.arg("-s");
cmd.arg(if sess.panic_strategy() == PanicStrategy::Abort {
@ -1296,43 +1319,40 @@ fn linker_with_args<'a, B: ArchiveBuilder<'a>>(
});
}
// OBJECT-FILES-YES, AUDIT-ORDER
link_sanitizer_runtime(sess, crate_type, cmd);
// OBJECT-FILES-NO, AUDIT-ORDER
// Linker plugins should be specified early in the list of arguments
// FIXME: How "early" exactly?
cmd.linker_plugin_lto();
// The default library location, we need this to find the runtime.
// The location of crates will be determined as needed.
let lib_path = sess.target_filesearch(PathKind::All).get_lib_path();
// target descriptor
let t = &sess.target.target;
// prefer system mingw-w64 libs, see get_crt_libs_path comment for more details
if cfg!(windows) && sess.target.target.llvm_target.contains("windows-gnu") {
if let Some(compiler_libs_path) = get_crt_libs_path(sess) {
cmd.include_path(&compiler_libs_path);
}
}
cmd.include_path(&fix_windows_verbatim_for_gcc(&lib_path));
// NO-OPT-OUT, OBJECT-FILES-NO, AUDIT-ORDER
// FIXME: Order-dependent, at least relatively to other args adding searh directories.
add_library_search_dirs(cmd, sess);
// OBJECT-FILES-YES
for obj in codegen_results.modules.iter().filter_map(|m| m.object.as_ref()) {
cmd.add_object(obj);
}
// NO-OPT-OUT, OBJECT-FILES-NO, AUDIT-ORDER
cmd.output_filename(out_filename);
// OBJECT-FILES-NO, AUDIT-ORDER
if crate_type == config::CrateType::Executable && sess.target.target.options.is_like_windows {
if let Some(ref s) = codegen_results.windows_subsystem {
cmd.subsystem(s);
}
}
// NO-OPT-OUT, OBJECT-FILES-NO, AUDIT-ORDER
// If we're building something like a dynamic library then some platforms
// need to make sure that all symbols are exported correctly from the
// dynamic library.
cmd.export_symbols(tmpdir, crate_type);
// OBJECT-FILES-YES
// When linking a dynamic library, we put the metadata into a section of the
// executable. This metadata is in a separate object file from the main
// object file, so we link that in here.
@ -1343,11 +1363,14 @@ fn linker_with_args<'a, B: ArchiveBuilder<'a>>(
}
}
// OBJECT-FILES-YES
let obj = codegen_results.allocator_module.as_ref().and_then(|m| m.object.as_ref());
if let Some(obj) = obj {
cmd.add_object(obj);
}
// OBJECT-FILES-NO, AUDIT-ORDER
// FIXME: Order dependent, applies to the following objects. Where should it be placed?
// Try to strip as much out of the generated object by removing unused
// sections if possible. See more comments in linker.rs
if !sess.opts.cg.link_dead_code {
@ -1355,10 +1378,11 @@ fn linker_with_args<'a, B: ArchiveBuilder<'a>>(
cmd.gc_sections(keep_metadata);
}
// NO-OPT-OUT, OBJECT-FILES-NO, AUDIT-ORDER
if crate_type == config::CrateType::Executable {
let mut position_independent_executable = false;
if t.options.position_independent_executables {
if sess.target.target.options.position_independent_executables {
if is_pic(sess)
&& !sess.crt_static(Some(crate_type))
&& !sess
@ -1385,9 +1409,10 @@ fn linker_with_args<'a, B: ArchiveBuilder<'a>>(
}
}
// OBJECT-FILES-NO, AUDIT-ORDER
let relro_level = match sess.opts.debugging_opts.relro_level {
Some(level) => level,
None => t.options.relro_level,
None => sess.target.target.options.relro_level,
};
match relro_level {
RelroLevel::Full => {
@ -1402,12 +1427,15 @@ fn linker_with_args<'a, B: ArchiveBuilder<'a>>(
RelroLevel::None => {}
}
// OBJECT-FILES-NO, AUDIT-ORDER
// Pass optimization flags down to the linker.
cmd.optimize();
// OBJECT-FILES-NO, AUDIT-ORDER
// Pass debuginfo flags down to the linker.
cmd.debuginfo();
// OBJECT-FILES-NO, AUDIT-ORDER
// We want to, by default, prevent the compiler from accidentally leaking in
// any system libraries, so we may explicitly ask linkers to not link to any
// libraries by default. Note that this does not happen for windows because
@ -1415,10 +1443,13 @@ fn linker_with_args<'a, B: ArchiveBuilder<'a>>(
// figure out which subset we wanted.
//
// This is all naturally configurable via the standard methods as well.
if !sess.opts.cg.default_linker_libraries.unwrap_or(false) && t.options.no_default_libraries {
if !sess.opts.cg.default_linker_libraries.unwrap_or(false)
&& sess.target.target.options.no_default_libraries
{
cmd.no_default_libraries();
}
// OBJECT-FILES-YES
// Take careful note of the ordering of the arguments we pass to the linker
// here. Linkers will assume that things on the left depend on things to the
// right. Things on the right cannot depend on things on the left. This is
@ -1456,6 +1487,8 @@ fn linker_with_args<'a, B: ArchiveBuilder<'a>>(
if sess.opts.debugging_opts.link_native_libraries.unwrap_or(true) {
add_upstream_native_libraries(cmd, sess, codegen_results, crate_type);
}
// NO-OPT-OUT, OBJECT-FILES-NO, AUDIT-ORDER
// Tell the linker what we're doing.
if crate_type != config::CrateType::Executable {
cmd.build_dylib(out_filename);
@ -1464,14 +1497,17 @@ fn linker_with_args<'a, B: ArchiveBuilder<'a>>(
cmd.build_static_executable();
}
// OBJECT-FILES-NO, AUDIT-ORDER
if sess.opts.cg.profile_generate.enabled() {
cmd.pgo_gen();
}
// OBJECT-FILES-NO, AUDIT-ORDER
if sess.opts.debugging_opts.control_flow_guard != CFGuard::Disabled {
cmd.control_flow_guard();
}
// OBJECT-FILES-NO, AUDIT-ORDER
// FIXME (#2397): At some point we want to rpath our guesses as to
// where extern libraries might live, based on the
// addl_lib_search_paths
@ -1496,17 +1532,19 @@ fn linker_with_args<'a, B: ArchiveBuilder<'a>>(
cmd.args(&rpath::get_rpath_flags(&mut rpath_config));
}
// OBJECT-FILES-MAYBE, CUSTOMIZATION-POINT
add_user_defined_link_args(cmd, sess, codegen_results);
// NO-OPT-OUT, OBJECT-FILES-NO, AUDIT-ORDER
cmd.finalize();
// NO-OPT-OUT
// NO-OPT-OUT, OBJECT-FILES-MAYBE, CUSTOMIZATION-POINT
add_late_link_args(cmd, sess, flavor, crate_type, codegen_results);
// NO-OPT-OUT
// NO-OPT-OUT, OBJECT-FILES-YES
add_post_link_objects(cmd, sess, crate_type);
// NO-OPT-OUT
// NO-OPT-OUT, OBJECT-FILES-MAYBE, CUSTOMIZATION-POINT
add_post_link_args(cmd, sess, flavor);
cmd.take_cmd()