rust/src/comp/back/link.rs
2011-08-12 12:08:27 -07:00

478 lines
17 KiB
Rust

import driver::session;
import lib::llvm::llvm;
import front::attr;
import middle::ty;
import metadata::encoder;
import middle::trans_common::crate_ctxt;
import std::str;
import std::fs;
import std::ivec;
import std::option;
import option::some;
import option::none;
import std::sha1::sha1;
import std::sort;
import syntax::ast;
import syntax::print::pprust;
import lib::llvm::llvm::ModuleRef;
import lib::llvm::llvm::ValueRef;
import lib::llvm::mk_pass_manager;
import lib::llvm::mk_target_data;
import lib::llvm::mk_type_names;
import lib::llvm::False;
import lib::llvm::True;
tag output_type {
output_type_none;
output_type_bitcode;
output_type_assembly;
output_type_object;
output_type_exe;
}
fn llvm_err(sess: session::session, msg: str) {
let buf = llvm::LLVMRustGetLastError();
if buf as uint == 0u {
sess.fatal(msg);
} else { sess.fatal(msg + ": " + str::str_from_cstr(buf)); }
}
fn link_intrinsics(sess: session::session, llmod: ModuleRef) {
let path = fs::connect(sess.get_opts().sysroot, "lib/intrinsics.bc");
let membuf =
llvm::LLVMRustCreateMemoryBufferWithContentsOfFile(str::buf(path));
if membuf as uint == 0u {
llvm_err(sess, "installation problem: couldn't open " + path);
fail;
}
let llintrinsicsmod = llvm::LLVMRustParseBitcode(membuf);
llvm::LLVMDisposeMemoryBuffer(membuf);
if llintrinsicsmod as uint == 0u {
llvm_err(sess, "installation problem: couldn't parse intrinsics.bc");
fail;
}
let linkres = llvm::LLVMLinkModules(llmod, llintrinsicsmod);
llvm::LLVMDisposeModule(llintrinsicsmod);
if linkres == False {
llvm_err(sess, "couldn't link the module with the intrinsics");
fail;
}
}
mod write {
fn is_object_or_assembly_or_exe(ot: output_type) -> bool {
if ot == output_type_assembly || ot == output_type_object ||
ot == output_type_exe {
ret true;
}
ret false;
}
// Decides what to call an intermediate file, given the name of the output
// and the extension to use.
fn mk_intermediate_name(output_path: str, extension: str) -> str {
let dot_pos = str::index(output_path, '.' as u8);
let stem;
if dot_pos < 0 {
stem = output_path;
} else { stem = str::substr(output_path, 0u, dot_pos as uint); }
ret stem + "." + extension;
}
fn run_passes(sess: session::session, llmod: ModuleRef, output: str) {
let opts = sess.get_opts();
if opts.time_llvm_passes { llvm::LLVMRustEnableTimePasses(); }
link_intrinsics(sess, llmod);
let pm = mk_pass_manager();
let td = mk_target_data(x86::get_data_layout());
llvm::LLVMAddTargetData(td.lltd, pm.llpm);
// TODO: run the linter here also, once there are llvm-c bindings for
// it.
// Generate a pre-optimization intermediate file if -save-temps was
// specified.
if opts.save_temps {
alt opts.output_type {
output_type_bitcode. {
if opts.optimize != 0u {
let filename = mk_intermediate_name(output, "no-opt.bc");
llvm::LLVMWriteBitcodeToFile(llmod, str::buf(filename));
}
}
_ {
let filename = mk_intermediate_name(output, "bc");
llvm::LLVMWriteBitcodeToFile(llmod, str::buf(filename));
}
}
}
if opts.verify { llvm::LLVMAddVerifierPass(pm.llpm); }
// FIXME: This is mostly a copy of the bits of opt's -O2 that are
// available in the C api.
// FIXME2: We might want to add optimization levels like -O1, -O2,
// -Os, etc
// FIXME3: Should we expose and use the pass lists used by the opt
// tool?
if opts.optimize != 0u {
let fpm = mk_pass_manager();
llvm::LLVMAddTargetData(td.lltd, fpm.llpm);
let FPMB = llvm::LLVMPassManagerBuilderCreate();
llvm::LLVMPassManagerBuilderSetOptLevel(FPMB, 2u);
llvm::LLVMPassManagerBuilderPopulateFunctionPassManager(FPMB,
fpm.llpm);
llvm::LLVMPassManagerBuilderDispose(FPMB);
llvm::LLVMRunPassManager(fpm.llpm, llmod);
let threshold: uint = 225u;
if opts.optimize == 3u { threshold = 275u; }
let MPMB = llvm::LLVMPassManagerBuilderCreate();
llvm::LLVMPassManagerBuilderSetOptLevel(MPMB, opts.optimize);
llvm::LLVMPassManagerBuilderSetSizeLevel(MPMB, 0);
llvm::LLVMPassManagerBuilderSetDisableUnitAtATime(MPMB, False);
llvm::LLVMPassManagerBuilderSetDisableUnrollLoops(MPMB, False);
llvm::LLVMPassManagerBuilderSetDisableSimplifyLibCalls(MPMB,
False);
if threshold != 0u {
llvm::LLVMPassManagerBuilderUseInlinerWithThreshold(MPMB,
threshold);
}
llvm::LLVMPassManagerBuilderPopulateModulePassManager(MPMB,
pm.llpm);
llvm::LLVMPassManagerBuilderDispose(MPMB);
}
if opts.verify { llvm::LLVMAddVerifierPass(pm.llpm); }
if is_object_or_assembly_or_exe(opts.output_type) {
let LLVMAssemblyFile: int = 0;
let LLVMObjectFile: int = 1;
let LLVMOptNone: int = 0; // -O0
let LLVMOptLess: int = 1; // -O1
let LLVMOptDefault: int = 2; // -O2, -Os
let LLVMOptAggressive: int = 3; // -O3
let CodeGenOptLevel;
alt opts.optimize {
0u { CodeGenOptLevel = LLVMOptNone; }
1u { CodeGenOptLevel = LLVMOptLess; }
2u { CodeGenOptLevel = LLVMOptDefault; }
3u { CodeGenOptLevel = LLVMOptAggressive; }
_ { fail; }
}
let FileType;
if opts.output_type == output_type_object ||
opts.output_type == output_type_exe {
FileType = LLVMObjectFile;
} else { FileType = LLVMAssemblyFile; }
// Write optimized bitcode if --save-temps was on.
if opts.save_temps {
// Always output the bitcode file with --save-temps
let filename = mk_intermediate_name(output, "opt.bc");
llvm::LLVMRunPassManager(pm.llpm, llmod);
llvm::LLVMWriteBitcodeToFile(llmod, str::buf(filename));
pm = mk_pass_manager();
// Save the assembly file if -S is used
if opts.output_type == output_type_assembly {
let triple = x86::get_target_triple();
llvm::LLVMRustWriteOutputFile(pm.llpm, llmod,
str::buf(triple),
str::buf(output),
LLVMAssemblyFile,
CodeGenOptLevel);
}
// Save the object file for -c or --save-temps alone
// This .o is needed when an exe is built
if opts.output_type == output_type_object ||
opts.output_type == output_type_exe {
let triple = x86::get_target_triple();
llvm::LLVMRustWriteOutputFile(pm.llpm, llmod,
str::buf(triple),
str::buf(output),
LLVMObjectFile,
CodeGenOptLevel);
}
} else {
// If we aren't saving temps then just output the file
// type corresponding to the '-c' or '-S' flag used
let triple = x86::get_target_triple();
llvm::LLVMRustWriteOutputFile(pm.llpm, llmod,
str::buf(triple),
str::buf(output), FileType,
CodeGenOptLevel);
}
// Clean up and return
llvm::LLVMDisposeModule(llmod);
if opts.time_llvm_passes { llvm::LLVMRustPrintPassTimings(); }
ret;
}
// If only a bitcode file is asked for by using the '--emit-llvm'
// flag, then output it here
llvm::LLVMRunPassManager(pm.llpm, llmod);
llvm::LLVMWriteBitcodeToFile(llmod, str::buf(output));
llvm::LLVMDisposeModule(llmod);
if opts.time_llvm_passes { llvm::LLVMRustPrintPassTimings(); }
}
}
/*
* Name mangling and its relationship to metadata. This is complex. Read
* carefully.
*
* The semantic model of Rust linkage is, broadly, that "there's no global
* namespace" between crates. Our aim is to preserve the illusion of this
* model despite the fact that it's not *quite* possible to implement on
* modern linkers. We initially didn't use system linkers at all, but have
* been convinced of their utility.
*
* There are a few issues to handle:
*
* - Linnkers operate on a flat namespace, so we have to flatten names.
* We do this using the C++ namespace-mangling technique. Foo::bar
* symbols and such.
*
* - Symbols with the same name but different types need to get different
* linkage-names. We do this by hashing a string-encoding of the type into
* a fixed-size (currently 16-byte hex) cryptographic hash function (CHF:
* we use SHA1) to "prevent collisions". This is not airtight but 16 hex
* digits on uniform probability means you're going to need 2**32 same-name
* symbols in the same process before you're even hitting birthday-paradox
* collision probability.
*
* - Symbols in different crates but with same names "within" the crate need
* to get different linkage-names.
*
* So here is what we do:
*
* - Separate the meta tags into two sets: exported and local. Only work with
* the exported ones when considering linkage.
*
* - Consider two exported tags as special (and mandatory): name and vers.
* Every crate gets them; if it doesn't name them explicitly we infer them
* as basename(crate) and "0.1", respectively. Call these CNAME, CVERS.
*
* - Define CMETA as all the non-name, non-vers exported meta tags in the
* crate (in sorted order).
*
* - Define CMH as hash(CMETA).
*
* - Compile our crate to lib CNAME-CMH-CVERS.so
*
* - Define STH(sym) as hash(CNAME, CMH, type_str(sym))
*
* - Suffix a mangled sym with ::STH@CVERS, so that it is unique in the
* name, non-name metadata, and type sense, and versioned in the way
* system linkers understand.
*
*/
type link_meta = {name: str, vers: str, extras_hash: str};
fn build_link_meta(sess: &session::session, c: &ast::crate, output: &str,
sha: sha1) -> link_meta {
type provided_metas =
{name: option::t[str],
vers: option::t[str],
cmh_items: [@ast::meta_item]};
fn provided_link_metas(sess: &session::session, c: &ast::crate) ->
provided_metas {
let name: option::t[str] = none;
let vers: option::t[str] = none;
let cmh_items: [@ast::meta_item] = ~[];
let linkage_metas = attr::find_linkage_metas(c.node.attrs);
attr::require_unique_names(sess, linkage_metas);
for meta: @ast::meta_item in linkage_metas {
if attr::get_meta_item_name(meta) == "name" {
alt attr::get_meta_item_value_str(meta) {
some(v) { name = some(v); }
none. { cmh_items += ~[meta]; }
}
} else if (attr::get_meta_item_name(meta) == "vers") {
alt attr::get_meta_item_value_str(meta) {
some(v) { vers = some(v); }
none. { cmh_items += ~[meta]; }
}
} else { cmh_items += ~[meta]; }
}
ret {name: name, vers: vers, cmh_items: cmh_items};
}
// This calculates CMH as defined above
fn crate_meta_extras_hash(sha: sha1, crate: &ast::crate,
metas: &provided_metas) -> str {
fn len_and_str(s: &str) -> str {
ret #fmt("%u_%s", str::byte_len(s), s);
}
fn len_and_str_lit(l: &ast::lit) -> str {
ret len_and_str(pprust::lit_to_str(@l));
}
let cmh_items = attr::sort_meta_items(metas.cmh_items);
sha.reset();
for m_: @ast::meta_item in cmh_items {
let m = m_;
alt m.node {
ast::meta_name_value(key, value) {
sha.input_str(len_and_str(key));
sha.input_str(len_and_str_lit(value));
}
ast::meta_word(name) { sha.input_str(len_and_str(name)); }
ast::meta_list(_, _) {
// FIXME (#607): Implement this
fail "unimplemented meta_item variant";
}
}
}
ret truncated_sha1_result(sha);
}
fn warn_missing(sess: &session::session, name: str, default: str) {
if !sess.get_opts().library { ret; }
sess.warn(#fmt("missing crate link meta '%s', using '%s' as default",
name, default));
}
fn crate_meta_name(sess: &session::session, crate: &ast::crate,
output: &str, metas: &provided_metas) -> str {
ret alt metas.name {
some(v) { v }
none. {
let name =
{
let os =
str::split(fs::basename(output), '.' as u8);
assert (ivec::len(os) >= 2u);
ivec::pop(os);
str::connect_ivec(os, ".")
};
warn_missing(sess, "name", name);
name
}
};
}
fn crate_meta_vers(sess: &session::session, crate: &ast::crate,
metas: &provided_metas) -> str {
ret alt metas.vers {
some(v) { v }
none. {
let vers = "0.0";
warn_missing(sess, "vers", vers);
vers
}
};
}
let provided_metas = provided_link_metas(sess, c);
let name = crate_meta_name(sess, c, output, provided_metas);
let vers = crate_meta_vers(sess, c, provided_metas);
let extras_hash = crate_meta_extras_hash(sha, c, provided_metas);
ret {name: name, vers: vers, extras_hash: extras_hash};
}
fn truncated_sha1_result(sha: sha1) -> str {
ret str::substr(sha.result_str(), 0u, 16u);
}
// This calculates STH for a symbol, as defined above
fn symbol_hash(tcx: ty::ctxt, sha: sha1, t: &ty::t, link_meta: &link_meta) ->
str {
// NB: do *not* use abbrevs here as we want the symbol names
// to be independent of one another in the crate.
sha.reset();
sha.input_str(link_meta.name);
sha.input_str("-");
// FIXME: This wants to be link_meta.meta_hash
sha.input_str(link_meta.name);
sha.input_str("-");
sha.input_str(encoder::encoded_ty(tcx, t));
let hash = truncated_sha1_result(sha);
// Prefix with _ so that it never blends into adjacent digits
ret "_" + hash;
}
fn get_symbol_hash(ccx: &@crate_ctxt, t: &ty::t) -> str {
let hash = "";
alt ccx.type_sha1s.find(t) {
some(h) { hash = h; }
none. {
hash = symbol_hash(ccx.tcx, ccx.sha, t, ccx.link_meta);
ccx.type_sha1s.insert(t, hash);
}
}
ret hash;
}
fn mangle(ss: &[str]) -> str {
// Follow C++ namespace-mangling style
let n = "_ZN"; // Begin name-sequence.
for s: str in ss { n += #fmt("%u%s", str::byte_len(s), s); }
n += "E"; // End name-sequence.
ret n;
}
fn exported_name(path: &[str], hash: &str, vers: &str) -> str {
// FIXME: versioning isn't working yet
ret mangle(path + ~[hash]); // + "@" + vers;
}
fn mangle_exported_name(ccx: &@crate_ctxt, path: &[str], t: &ty::t) -> str {
let hash = get_symbol_hash(ccx, t);
ret exported_name(path, hash, ccx.link_meta.vers);
}
fn mangle_internal_name_by_type_only(ccx: &@crate_ctxt, t: &ty::t, name: &str)
-> str {
let s = util::ppaux::ty_to_short_str(ccx.tcx, t);
let hash = get_symbol_hash(ccx, t);
ret mangle(~[name, s, hash]);
}
fn mangle_internal_name_by_path_and_seq(ccx: &@crate_ctxt, path: &[str],
flav: &str) -> str {
ret mangle(path + ~[ccx.names.next(flav)]);
}
fn mangle_internal_name_by_path(ccx: &@crate_ctxt, path: &[str]) -> str {
ret mangle(path);
}
fn mangle_internal_name_by_seq(ccx: &@crate_ctxt, flav: &str) -> str {
ret ccx.names.next(flav);
}
//
// Local Variables:
// mode: rust
// fill-column: 78;
// indent-tabs-mode: nil
// c-basic-offset: 4
// buffer-file-coding-system: utf-8-unix
// compile-command: "make -k -C $RBUILD 2>&1 | sed -e 's/\\/x\\//x:\\//g'";
// End:
//