diff options
Diffstat (limited to 'build/cxx/rule.cxx')
| -rw-r--r-- | build/cxx/rule.cxx | 425 |
1 files changed, 257 insertions, 168 deletions
diff --git a/build/cxx/rule.cxx b/build/cxx/rule.cxx index 47f925d..8d91e1c 100644 --- a/build/cxx/rule.cxx +++ b/build/cxx/rule.cxx @@ -108,6 +108,9 @@ namespace build return nullptr; } + static void + inject_prerequisites (action, target&, cxx&, scope&); + recipe compile:: apply (action a, target& xt, void* v) const { @@ -149,10 +152,11 @@ namespace build t.prerequisite_targets.push_back (&pt); } - // Inject additional prerequisites. For now we only do it for - // update and default. + // Inject additional prerequisites. We only do it for update + // since chances are we will have to update some of our + // prerequisites in the process (auto-generated source code). // - if (a.operation () == update_id || a.operation () == default_id) + if (a.operation () == update_id) { // The cached prerequisite target (sp.target) should be the // same as what is in t.prerequisite_targets since we used @@ -161,8 +165,7 @@ namespace build prerequisite& sp (*static_cast<prerequisite*> (v)); cxx& st (dynamic_cast<cxx&> (*sp.target)); - if (st.mtime () != timestamp_nonexistent) - inject_prerequisites (a, t, st, sp.scope); + inject_prerequisites (a, t, st, sp.scope); } switch (a) @@ -240,7 +243,7 @@ namespace build if (++i == e) break; // Let the compiler complain. - d = dir_path (i->value); + d = i->simple () ? dir_path (i->value) : i->dir; } else if (i->value.compare (0, 2, "-I") == 0) d = dir_path (i->value, 2, string::npos); @@ -370,8 +373,8 @@ namespace build return r; } - void compile:: - inject_prerequisites (action a, target& t, const cxx& s, scope& ds) const + static void + inject_prerequisites (action a, target& t, cxx& s, scope& ds) { tracer trace ("cxx::compile::inject_prerequisites"); @@ -408,212 +411,298 @@ namespace build 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 generated headers. + // 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. + // that. Or just detect relative paths and error out? // args.push_back (s.path ().string ().c_str ()); - args.push_back (nullptr); - if (verb >= 2) - print_process (args); - level5 ([&]{trace << "target: " << t;}); - try - { - process pr (args.data (), false, false, true); - ifdstream is (pr.in_ofd); - prefix_map pm; // Build it lazily. + // 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 prerequsites that we have already processed + // (i.e., they are already in our prerequsite_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 prerequsites 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); - for (bool first (true), second (true); !is.eof (); ) - { - string l; - getline (is, l); + size_t skip_count (0); + for (bool restart (true); restart; ) + { + restart = false; - if (is.fail () && !is.eof ()) - fail << "io error while parsing g++ -M output"; + if (verb >= 2) + print_process (args); - size_t pos (0); + try + { + process pr (args.data (), false, false, true); + ifdstream is (pr.in_ofd); - if (first) + size_t skip (skip_count); + for (bool first (true), second (true); !(restart || is.eof ()); ) { - // Empty output should mean the wait() call below will return - // false. - // - if (l.empty ()) - break; + string l; + getline (is, l); - assert (l[0] == '*' && l[1] == ':' && l[2] == ' '); + if (is.fail () && !is.eof ()) + fail << "io error while parsing g++ -M output"; - first = false; + size_t pos (0); - // While normally we would have the source file on the - // first line, if too long, it will be move to the next - // line and all we will have on this line is "*: \". - // - if (l.size () == 4 && l[3] == '\\') - continue; - else - pos = 3; // Skip "*: ". + if (first) + { + // Empty output should mean the wait() call below will return + // false. + // + if (l.empty ()) + break; - // Fall through to the 'second' block. - } + assert (l[0] == '*' && l[1] == ':' && l[2] == ' '); - if (second) - { - second = false; - next (l, pos); // Skip the source file. - } + first = false; - auto g ( - make_exception_guard ( - [](const target& s) - { - info << "while extracting dependencies from " << s; - }, - s)); + // 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 "*: ". - while (pos != l.size ()) - { - path f (next (l, pos)); - f.normalize (); + // Fall through to the 'second' block. + } - if (!f.absolute ()) + if (second) { - // This is probably as often an error as an auto-generated - // file, so trace at level 3. - // - level3 ([&]{trace << "non-existent header '" << f << "'";}); + second = false; + next (l, pos); // Skip the source file. + } - // 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); + // If things go wrong (and they often do in this area), give + // the user a bit extra context. + // + auto g ( + make_exception_guard ( + [](target& s) + { + info << "while extracting dependencies from " << s; + }, + s)); - // 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)); + while (pos != l.size ()) + { + string fs (next (l, pos)); - // Find the most qualified prefix of which we are a - // sub-path. + // Skip until where we left off. // - auto i (pm.end ()); + if (skip != 0) + { + skip--; + continue; + } - if (!pm.empty ()) + path f (move (fs)); + f.normalize (); + + if (!f.absolute ()) { - const dir_path& d (f.directory ()); - i = pm.upper_bound (d); - --i; // Greatest less than. + // This is probably as often an error as an auto-generated + // file, so trace at level 3. + // + level3 ([&]{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); + --i; // Greatest less than. - if (!d.sub (i->first)) // We might still not be a sub. - i = pm.end (); - } + if (!d.sub (i->first)) // We might still not be a sub. + i = pm.end (); + } - if (i == pm.end ()) - fail << "unable to map presumably auto-generated header '" - << f << "' to a project"; + if (i == pm.end ()) + fail << "unable to map presumably auto-generated header '" + << f << "' to a project"; - f = i->second / f; - } + f = i->second / f; + } - level5 ([&]{trace << "injecting " << f;}); + level5 ([&]{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 : "")); + // 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 : "")); - // Find or insert target. - // - // If there is no extension (e.g., standard C++ headers), - // then assume it is a header. Otherwise, let the standard - // mechanism derive the type from the extension. @@ TODO. - // + // 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. + // + if (scope* r = scopes.find (d).root_scope ()) + { + // Get cached (or build) a map of the extensions for the + // C/C++ files this project is using. + // + const ext_map& m (build_ext_map (*r)); + + auto i (m.find (e)); + if (i != m.end ()) + tt = i->second; + } - // 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. - // - if (scope* r = scopes.find (d).root_scope ()) - { - // Get cahed (or build) a map of the extensions for the - // C/C++ files this project is using. + // If it is outside any project, or the project doesn't have + // such an extension, assume it is a plain old C header. // - const ext_map& m (build_ext_map (*r)); + if (tt == nullptr) + tt = &h::static_type; - auto i (m.find (e)); - if (i != m.end ()) - tt = i->second; - } + // Find or insert target. + // + path_target& pt ( + static_cast<path_target&> (search (*tt, d, n, e, &ds))); - // 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; + // Assign path. + // + if (pt.path ().empty ()) + pt.path (move (f)); - path_target& pt ( - static_cast<path_target&> (search (*tt, d, n, e, &ds))); + // Match to a rule. + // + build::match (a, pt); - // Assign path. - // - if (pt.path ().empty ()) - pt.path (move (f)); + // 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 updating (again, + // system headers, for example) and the rule that will match + // them is fallback path_rule. So we are going to do a little + // fast-path optimization by detecting this common case. + // + recipe_function* const* recipe ( + pt.recipe (a).target<recipe_function*> ()); - // Match to a rule. - // - build::match (a, pt); + if (recipe == nullptr || *recipe != &path_rule::perform_update) + { + // 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); + execute_direct (a, pt); + + if (pt.state != os && pt.state != target_state::unchanged) + { + level5 ([&]{trace << "updated " << pt << ", restarting";}); + restart = true; + } + } - // Add to our prerequisite target list. - // - t.prerequisite_targets.push_back (&pt); + // Add to our prerequisite target list. + // + t.prerequisite_targets.push_back (&pt); + skip_count++; + } } - } - // We assume the child process issued some diagnostics. - // - if (!pr.wait ()) - throw failed (); - } - catch (const process_error& e) - { - error << "unable to execute " << args[0] << ": " << e.what (); + // 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 (); - // 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); + // We assume the child process issued some diagnostics. + // + if (!pr.wait ()) + throw failed (); + } + catch (const process_error& e) + { + error << "unable to execute " << args[0] << ": " << e.what (); - throw failed (); + // 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 (); + } } } |