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Diffstat (limited to 'build2/cxx/compile.cxx')
| -rw-r--r-- | build2/cxx/compile.cxx | 794 |
1 files changed, 794 insertions, 0 deletions
diff --git a/build2/cxx/compile.cxx b/build2/cxx/compile.cxx new file mode 100644 index 0000000..bc332b4 --- /dev/null +++ b/build2/cxx/compile.cxx @@ -0,0 +1,794 @@ +// file : build2/cxx/compile.cxx -*- C++ -*- +// copyright : Copyright (c) 2014-2015 Code Synthesis Ltd +// license : MIT; see accompanying LICENSE file + +#include <build2/cxx/compile> + +#include <map> +#include <string> +#include <cstddef> // size_t +#include <cstdlib> // exit() +#include <utility> // move() + +#include <butl/process> +#include <butl/utility> // reverse_iterate +#include <butl/fdstream> +#include <butl/path-map> + +#include <build2/types> +#include <build2/scope> +#include <build2/variable> +#include <build2/algorithm> +#include <build2/diagnostics> +#include <build2/context> + +#include <build2/bin/target> +#include <build2/cxx/target> + +#include <build2/cxx/utility> +#include <build2/cxx/link> + +using namespace std; +using namespace butl; + +namespace build2 +{ + namespace cxx + { + using namespace bin; + + match_result compile:: + match (action a, target& t, const string&) const + { + tracer trace ("cxx::compile::match"); + + // @@ TODO: + // + // - check prerequisites: single source file + // - if path already assigned, verify extension? + // + + // See if we have a C++ source file. Iterate in reverse so that + // a source file specified for an obj*{} member overrides the one + // specified for the group. Also "see through" groups. + // + for (prerequisite_member p: reverse_group_prerequisite_members (a, t)) + { + if (p.is_a<cxx> ()) + return p; + } + + level4 ([&]{trace << "no c++ source file for target " << t;}); + return nullptr; + } + + static void + inject_prerequisites (action, target&, cxx&, scope&); + + recipe compile:: + apply (action a, target& xt, const match_result& mr) const + { + path_target& t (static_cast<path_target&> (xt)); + + // Derive file name from target name. + // + if (t.path ().empty ()) + t.derive_path ("o", nullptr, (t.is_a<objso> () ? "-so" : nullptr)); + + // Inject dependency on the output directory. + // + inject_parent_fsdir (a, t); + + // Search and match all the existing prerequisites. The injection + // code (below) takes care of the ones it is adding. + // + // When cleaning, ignore prerequisites that are not in the same + // or a subdirectory of our strong amalgamation. + // + const dir_path* amlg ( + a.operation () != clean_id + ? nullptr + : &t.strong_scope ().out_path ()); + + link::search_paths_cache lib_paths; // Extract lazily. + + for (prerequisite_member p: group_prerequisite_members (a, t)) + { + // A dependency on a library is there so that we can get its + // cxx.export.poptions. In particular, making sure it is + // executed before us will only restrict parallelism. But we + // do need to pre-match it in order to get its + // prerequisite_targets populated. This is the "library + // meta-information protocol". See also append_lib_options() + // above. + // + if (p.is_a<lib> () || p.is_a<liba> () || p.is_a<libso> ()) + { + if (a.operation () == update_id) + { + // Handle imported libraries. We know that for such libraries + // we don't need to do match() in order to get options (if + // any, they would be set by search_library()). + // + if (p.proj () == nullptr || + link::search_library (lib_paths, p.prerequisite) == nullptr) + { + match_only (a, p.search ()); + } + } + + continue; + } + + target& pt (p.search ()); + + if (a.operation () == clean_id && !pt.dir.sub (*amlg)) + continue; + + build2::match (a, pt); + t.prerequisite_targets.push_back (&pt); + } + + // Inject additional prerequisites. We only do it when + // performing update since chances are we will have to + // update some of our prerequisites in the process (auto- + // generated source code). + // + if (a == perform_update_id) + { + // The cached prerequisite target should be the same as what + // is in t.prerequisite_targets since we used standard + // search() and match() above. + // + // @@ Ugly. + // + cxx& st ( + dynamic_cast<cxx&> ( + mr.target != nullptr ? *mr.target : *mr.prerequisite->target)); + inject_prerequisites (a, t, st, mr.prerequisite->scope); + } + + switch (a) + { + case perform_update_id: return &perform_update; + case perform_clean_id: return &perform_clean; + default: return noop_recipe; // Configure update. + } + } + + // Reverse-lookup target type from extension. + // + static const target_type* + map_extension (scope& s, const string& n, const string& e) + { + // We will just have to try all of the possible ones, in the + // "most likely to match" order. + // + const variable& var (var_pool.find ("extension")); + + auto test = [&s, &n, &e, &var] (const target_type& tt) + -> const target_type* + { + if (auto l = s.lookup (tt, n, var)) + if (as<string> (*l) == e) + return &tt; + + return nullptr; + }; + + if (auto r = test (hxx::static_type)) return r; + if (auto r = test (h::static_type)) return r; + if (auto r = test (ixx::static_type)) return r; + if (auto r = test (txx::static_type)) return r; + if (auto r = test (cxx::static_type)) return r; + if (auto r = test (c::static_type)) return r; + + return nullptr; + } + + // Mapping of include prefixes (e.g., foo in <foo/bar>) for auto- + // generated headers to directories where they will be generated. + // + // We are using a prefix map of directories (dir_path_map) instead + // of just a map in order also cover sub-paths (e.g., <foo/more/bar> + // if we continue with the example). Specifically, we need to make + // sure we don't treat foobar as a sub-directory of foo. + // + // @@ The keys should be canonicalized. + // + using prefix_map = dir_path_map<dir_path>; + + static void + append_prefixes (prefix_map& m, target& t, const char* var) + { + tracer trace ("cxx::append_prefixes"); + + // If this target does not belong to any project (e.g, an + // "imported as installed" library), then it can't possibly + // generate any headers for us. + // + scope* rs (t.base_scope ().root_scope ()); + if (rs == nullptr) + return; + + const dir_path& out_base (t.dir); + const dir_path& out_root (rs->out_path ()); + + if (auto l = t[var]) + { + const auto& v (as<strings> (*l)); + + for (auto i (v.begin ()), e (v.end ()); i != e; ++i) + { + // -I can either be in the "-Ifoo" or "-I foo" form. + // + dir_path d; + if (*i == "-I") + { + if (++i == e) + break; // Let the compiler complain. + + d = dir_path (*i); + } + else if (i->compare (0, 2, "-I") == 0) + d = dir_path (*i, 2, string::npos); + else + continue; + + level6 ([&]{trace << "-I '" << d << "'";}); + + // If we are relative or not inside our project root, then + // ignore. + // + if (d.relative () || !d.sub (out_root)) + continue; + + // If the target directory is a sub-directory of the include + // directory, then the prefix is the difference between the + // two. Otherwise, leave it empty. + // + // The idea here is to make this "canonical" setup work auto- + // magically: + // + // 1. We include all files with a prefix, e.g., <foo/bar>. + // 2. The library target is in the foo/ sub-directory, e.g., + // /tmp/foo/. + // 3. The poptions variable contains -I/tmp. + // + dir_path p (out_base.sub (d) ? out_base.leaf (d) : dir_path ()); + + auto j (m.find (p)); + + if (j != m.end ()) + { + if (j->second != d) + { + // We used to reject duplicates but it seems this can + // be reasonably expected to work according to the order + // of the -I options. + // + if (verb >= 4) + trace << "overriding dependency prefix '" << p << "'\n" + << " old mapping to " << j->second << "\n" + << " new mapping to " << d; + + j->second = d; + } + } + else + { + level6 ([&]{trace << "'" << p << "' = '" << d << "'";}); + m.emplace (move (p), move (d)); + } + } + } + } + + // Append library prefixes based on the cxx.export.poptions variables + // recursively, prerequisite libraries first. + // + static void + append_lib_prefixes (prefix_map& m, target& l) + { + for (target* t: l.prerequisite_targets) + { + if (t == nullptr) + continue; + + if (t->is_a<lib> () || t->is_a<liba> () || t->is_a<libso> ()) + append_lib_prefixes (m, *t); + } + + append_prefixes (m, l, "cxx.export.poptions"); + } + + static prefix_map + build_prefix_map (target& t) + { + prefix_map m; + + // First process the include directories from prerequisite + // libraries. Note that here we don't need to see group + // members (see apply()). + // + for (prerequisite& p: group_prerequisites (t)) + { + target& pt (*p.target); // Already searched and matched. + + if (pt.is_a<lib> () || pt.is_a<liba> () || pt.is_a<libso> ()) + append_lib_prefixes (m, pt); + } + + // Then process our own. + // + append_prefixes (m, t, "cxx.poptions"); + + return m; + } + + // Return the next make prerequisite starting from the specified + // position and update position to point to the start of the + // following prerequisite or l.size() if there are none left. + // + static string + next (const string& l, size_t& p) + { + size_t n (l.size ()); + + // Skip leading spaces. + // + for (; p != n && l[p] == ' '; p++) ; + + // Lines containing multiple prerequisites are 80 characters max. + // + string r; + r.reserve (n); + + // Scan the next prerequisite while watching out for escape sequences. + // + for (; p != n && l[p] != ' '; p++) + { + char c (l[p]); + + if (c == '\\') + c = l[++p]; + + r += c; + } + + // Skip trailing spaces. + // + for (; p != n && l[p] == ' '; p++) ; + + // Skip final '\'. + // + if (p == n - 1 && l[p] == '\\') + p++; + + return r; + } + + static void + inject_prerequisites (action a, target& t, cxx& s, scope& ds) + { + tracer trace ("cxx::compile::inject_prerequisites"); + + scope& rs (t.root_scope ()); + const string& cxx (as<string> (*rs["config.cxx"])); + + cstrings args {cxx.c_str ()}; + + // Add cxx.export.poptions from prerequisite libraries. Note + // that here we don't need to see group members (see apply()). + // + for (prerequisite& p: group_prerequisites (t)) + { + target& pt (*p.target); // Already searched and matched. + + if (pt.is_a<lib> () || pt.is_a<liba> () || pt.is_a<libso> ()) + append_lib_options (args, pt, "cxx.export.poptions"); + } + + append_options (args, t, "cxx.poptions"); + + // @@ Some C++ options (e.g., -std, -m) affect the preprocessor. + // Or maybe they are not C++ options? Common options? + // + append_options (args, t, "cxx.coptions"); + + string std; // Storage. + append_std (args, t, std); + + if (t.is_a<objso> ()) + args.push_back ("-fPIC"); + + args.push_back ("-M"); // Note: -MM -MG skips missing <>-included. + args.push_back ("-MG"); // Treat missing headers as generated. + args.push_back ("-MQ"); // Quoted target name. + args.push_back ("*"); // Old versions can't handle empty target name. + + // We are using absolute source file path in order to get absolute + // paths in the result. Any relative paths in the result are non- + // existent, potentially auto-generated headers. + // + // @@ We will also have to use absolute -I paths to guarantee + // that. Or just detect relative paths and error out? + // + args.push_back (s.path ().string ().c_str ()); + args.push_back (nullptr); + + level6 ([&]{trace << "target: " << t;}); + + // Build the prefix map lazily only if we have non-existent files. + // Also reuse it over restarts since it doesn't change. + // + prefix_map pm; + + // If any prerequisites that we have extracted changed, then we + // have to redo the whole thing. The reason for this is auto- + // generated headers: the updated header may now include a yet- + // non-existent header. Unless we discover this and generate it + // (which, BTW, will trigger another restart since that header, + // in turn, can also include auto-generated headers), we will + // end up with an error during compilation proper. + // + // One complication with this restart logic is that we will see + // a "prefix" of prerequisites that we have already processed + // (i.e., they are already in our prerequisite_targets list) and + // we don't want to keep redoing this over and over again. One + // thing to note, however, is that the prefix that we have seen + // on the previous run must appear exactly the same in the + // subsequent run. The reason for this is that none of the files + // that it can possibly be based on have changed and thus it + // should be exactly the same. To put it another way, the + // presence or absence of a file in the dependency output can + // only depend on the previous files (assuming the compiler + // outputs them as it encounters them and it is hard to think + // of a reason why would someone do otherwise). And we have + // already made sure that all those files are up to date. And + // here is the way we are going to exploit this: we are going + // to keep track of how many prerequisites we have processed so + // far and on restart skip right to the next one. + // + // Also, before we do all that, make sure the source file itself + // if up to date. + // + execute_direct (a, s); + + size_t skip_count (0); + for (bool restart (true); restart; ) + { + restart = false; + + if (verb >= 3) + print_process (args); + + try + { + process pr (args.data (), 0, -1); // Open pipe to stdout. + ifdstream is (pr.in_ofd); + + size_t skip (skip_count); + for (bool first (true), second (true); !(restart || is.eof ()); ) + { + string l; + getline (is, l); + + if (is.fail () && !is.eof ()) + fail << "error reading C++ compiler -M output"; + + size_t pos (0); + + if (first) + { + // Empty output should mean the wait() call below will return + // false. + // + if (l.empty ()) + break; + + assert (l[0] == '*' && l[1] == ':' && l[2] == ' '); + + first = false; + + // While normally we would have the source file on the + // first line, if too long, it will be moved to the next + // line and all we will have on this line is "*: \". + // + if (l.size () == 4 && l[3] == '\\') + continue; + else + pos = 3; // Skip "*: ". + + // Fall through to the 'second' block. + } + + if (second) + { + second = false; + next (l, pos); // Skip the source file. + } + + // If things go wrong (and they often do in this area), give + // the user a bit extra context. + // + auto g ( + make_exception_guard ( + [&s]() + { + info << "while extracting dependencies from " << s; + })); + + while (pos != l.size ()) + { + string fs (next (l, pos)); + + // Skip until where we left off. + // + if (skip != 0) + { + skip--; + continue; + } + + path f (move (fs)); + f.normalize (); + + if (!f.absolute ()) + { + // This is probably as often an error as an auto-generated + // file, so trace at level 4. + // + level4 ([&]{trace << "non-existent header '" << f << "'";}); + + // If we already did it and build_prefix_map() returned empty, + // then we would have failed below. + // + if (pm.empty ()) + pm = build_prefix_map (t); + + // First try the whole file. Then just the directory. + // + // @@ Has to be a separate map since the prefix can be + // the same as the file name. + // + // auto i (pm.find (f)); + + // Find the most qualified prefix of which we are a + // sub-path. + // + auto i (pm.end ()); + + if (!pm.empty ()) + { + const dir_path& d (f.directory ()); + i = pm.upper_bound (d); + + // Get the greatest less than, if any. We might + // still not be a sub. Note also that we still + // have to check the last element is upper_bound() + // returned end(). + // + if (i == pm.begin () || !d.sub ((--i)->first)) + i = pm.end (); + } + + if (i == pm.end ()) + fail << "unable to map presumably auto-generated header '" + << f << "' to a project"; + + f = i->second / f; + } + + level6 ([&]{trace << "injecting " << f;}); + + // Split the name into its directory part, the name part, and + // extension. Here we can assume the name part is a valid + // filesystem name. + // + // Note that if the file has no extension, we record an empty + // extension rather than NULL (which would signify that the + // default extension should be added). + // + dir_path d (f.directory ()); + string n (f.leaf ().base ().string ()); + const char* es (f.extension ()); + const string* e (&extension_pool.find (es != nullptr ? es : "")); + + // Determine the target type. + // + const target_type* tt (nullptr); + + // See if this directory is part of any project out_root + // hierarchy. Note that this will miss all the headers + // that come from src_root (so they will be treated as + // generic C headers below). Generally, we don't have + // the ability to determine that some file belongs to + // src_root of some project. But that's not a problem + // for our purposes: it is only important for us to + // accurately determine target types for headers that + // could be auto-generated. + // + scope& b (scopes.find (d)); + if (b.root_scope () != nullptr) + tt = map_extension (b, n, *e); + + // If it is outside any project, or the project doesn't have + // such an extension, assume it is a plain old C header. + // + if (tt == nullptr) + tt = &h::static_type; + + // Find or insert target. + // + path_target& pt ( + static_cast<path_target&> (search (*tt, d, n, e, &ds))); + + // Assign path. + // + if (pt.path ().empty ()) + pt.path (move (f)); + + // Match to a rule. + // + build2::match (a, pt); + + // Update it. + // + // There would normally be a lot of headers for every source + // file (think all the system headers) and this can get + // expensive. At the same time, most of these headers are + // existing files that we will never be updated (again, + // system headers, for example) and the rule that will match + // them is fallback file_rule. That rule has an optimization + // in that it returns noop_recipe (which causes the target + // state to be automatically set to unchanged) if the file + // is known to be up to date. + // + if (pt.state () != target_state::unchanged) + { + // We only want to restart if our call to execute() actually + // caused an update. In particular, the target could already + // have been in target_state::changed because of a dependency + // extraction run for some other source file. + // + target_state os (pt.state ()); + target_state ns (execute_direct (a, pt)); + + if (ns != os && ns != target_state::unchanged) + { + level6 ([&]{trace << "updated " << pt << ", restarting";}); + restart = true; + } + } + + // Add to our prerequisite target list. + // + t.prerequisite_targets.push_back (&pt); + skip_count++; + } + } + + // We may not have read all the output (e.g., due to a restart), + // so close the file descriptor before waiting to avoid blocking + // the other end. + // + is.close (); + + // We assume the child process issued some diagnostics. + // + if (!pr.wait ()) + { + // In case of a restarts, we closed our end of the pipe early + // which might have caused the other end to fail. So far we + // experienced this on Fedora 23 with GCC 5.3.1 and there were + // no diagnostics issued, just the non-zero exit status. If we + // do get diagnostics, then we will have to read and discard the + // output until eof. + // + if (!restart) + throw failed (); + } + } + catch (const process_error& e) + { + error << "unable to execute " << args[0] << ": " << e.what (); + + // In a multi-threaded program that fork()'ed but did not exec(), + // it is unwise to try to do any kind of cleanup (like unwinding + // the stack and running destructors). + // + if (e.child ()) + exit (1); + + throw failed (); + } + } + } + + target_state compile:: + perform_update (action a, target& xt) + { + path_target& t (static_cast<path_target&> (xt)); + cxx* s (execute_prerequisites<cxx> (a, t, t.mtime ())); + + if (s == nullptr) + return target_state::unchanged; + + // Translate paths to relative (to working directory) ones. This + // results in easier to read diagnostics. + // + path relo (relative (t.path ())); + path rels (relative (s->path ())); + + scope& rs (t.root_scope ()); + const string& cxx (as<string> (*rs["config.cxx"])); + + cstrings args {cxx.c_str ()}; + + // Add cxx.export.poptions from prerequisite libraries. Note that + // here we don't need to see group members (see apply()). + // + for (prerequisite& p: group_prerequisites (t)) + { + target& pt (*p.target); // Already searched and matched. + + if (pt.is_a<lib> () || pt.is_a<liba> () || pt.is_a<libso> ()) + append_lib_options (args, pt, "cxx.export.poptions"); + } + + append_options (args, t, "cxx.poptions"); + append_options (args, t, "cxx.coptions"); + + string std; // Storage. + append_std (args, t, std); + + if (t.is_a<objso> ()) + args.push_back ("-fPIC"); + + args.push_back ("-o"); + args.push_back (relo.string ().c_str ()); + + args.push_back ("-c"); + args.push_back (rels.string ().c_str ()); + + args.push_back (nullptr); + + if (verb >= 2) + print_process (args); + else if (verb) + text << "c++ " << *s; + + try + { + process pr (args.data ()); + + if (!pr.wait ()) + throw failed (); + + // Should we go to the filesystem and get the new mtime? We + // know the file has been modified, so instead just use the + // current clock time. It has the advantage of having the + // subseconds precision. + // + t.mtime (system_clock::now ()); + return target_state::changed; + } + catch (const process_error& e) + { + error << "unable to execute " << args[0] << ": " << e.what (); + + // In a multi-threaded program that fork()'ed but did not exec(), + // it is unwise to try to do any kind of cleanup (like unwinding + // the stack and running destructors). + // + if (e.child ()) + exit (1); + + throw failed (); + } + } + + compile compile::instance; + } +} |