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-rw-r--r--build/cxx/rule4
-rw-r--r--build/cxx/rule.cxx425
2 files changed, 257 insertions, 172 deletions
diff --git a/build/cxx/rule b/build/cxx/rule
index 8c575fe..8b42fc2 100644
--- a/build/cxx/rule
+++ b/build/cxx/rule
@@ -30,10 +30,6 @@ namespace build
static target_state
perform_update (action, target&);
-
- private:
- void
- inject_prerequisites (action, target&, const cxx&, scope&) const;
};
class link: public rule
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 ();
+ }
}
}