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authorBoris Kolpackov <boris@codesynthesis.com>2020-06-08 13:18:31 +0200
committerBoris Kolpackov <boris@codesynthesis.com>2020-06-08 13:18:31 +0200
commiteebb47a613e47b2c25d64d5766323dfeeb5c3a73 (patch)
treea4a01e0dcd59e5efb12abfcc6c5d15def54c533d /libbuild2/rule.cxx
parent758a50eb1825f2e0c1acd5c61d36bb5b866585b8 (diff)
Hash ad hoc prerequsites for ad hoc recipe change detection
Diffstat (limited to 'libbuild2/rule.cxx')
-rw-r--r--libbuild2/rule.cxx198
1 files changed, 139 insertions, 59 deletions
diff --git a/libbuild2/rule.cxx b/libbuild2/rule.cxx
index 0df6517..f534ff9 100644
--- a/libbuild2/rule.cxx
+++ b/libbuild2/rule.cxx
@@ -534,60 +534,152 @@ namespace build2
const file& t (xt.as<file> ());
const path& tp (t.path ());
- // The script can reference a program in one of four ways:
+ // How should we hash target and prerequisite sets ($> and $<)? We could
+ // hash them as target names (i.e., the same as the $>/< content) or as
+ // paths (only for path-based targets). While names feel more general,
+ // they are also more expensive to compute. And for path-based targets,
+ // path is generally a good proxy for the target name. Since the bulk of
+ // the ad hoc recipes will presumably be operating exclusively on
+ // path-based targets, let's do it both ways.
//
- // 1. As an (imported) target (e.g., $cli)
- //
- // 2. As a process_path_ex (e.g., $cxx.path).
- //
- // 3. As a builtin (e.g., sed)
- //
- // 4. As a program path/name.
- //
- // When it comes to change tracking, there is nothing we can do for (4)
- // and there is nothing to do for (3) (assuming builtin semantics is
- // stable/backwards-compatible). The (2) case is handled automatically by
- // hashing all the variable values referenced by the script (see below),
- // which in case of process_path_ex includes the checksum, if available.
- //
- // This leaves the (1) case, which itself splits into two sub-cases: the
- // target comes with the dependency information (e.g., imported from a
- // project via an export stub) or it does not (e.g., imported as
- // installed). We don't need to do anything extra for the first sub-case
- // since the target's state/mtime can be relied upon like any other
- // prerequisite. Which cannot be said about the second sub-case, where we
- // reply on checksum that may be included as part of the target metadata.
- //
- // So what we are going to do here is hash checksum metadata of every
- // executable prerequisite target that has it. We do it before executing
- // in order to include ad hoc prerequisites (which feels like the right
- // thing to do; the user may mark tools as ad hoc in order to omit them
- // from $<). Note, however, that this is only required if the script
- // doesn't track the dependency changes itself.
+ auto hash_target = [ns = names ()] (sha256& cs, const target& t) mutable
+ {
+ if (const path_target* pt = t.is_a<path_target> ())
+ cs.append (pt->path ().string ());
+ else
+ {
+ ns.clear ();
+ t.as_name (ns);
+ for (const name& n: ns)
+ to_checksum (cs, n);
+ }
+ };
+
+ // Update prerequisites and determine if any of them render this target
+ // out-of-date.
//
- sha256 prog_cs;
- if (!script.depdb_clear)
+ timestamp mt (t.load_mtime ());
+ optional<target_state> ps;
+
+ sha256 pcs, ecs;
{
- for (const target* pt: t.prerequisite_targets[a])
+ // This is essentially ps=execute_prerequisites(a, t, mt) which we
+ // cannot use because we need to see ad hoc prerequisites.
+ //
+ size_t busy (ctx.count_busy ());
+ size_t exec (ctx.count_executed ());
+
+ target_state rs (target_state::unchanged);
+
+ wait_guard wg (ctx, busy, t[a].task_count);
+
+ for (const target*& pt: t.prerequisite_targets[a])
+ {
+ if (pt == nullptr) // Skipped.
+ continue;
+
+ target_state s (execute_async (a, *pt, busy, t[a].task_count));
+
+ if (s == target_state::postponed)
+ {
+ rs |= s;
+ pt = nullptr;
+ }
+ }
+
+ wg.wait ();
+
+ bool e (mt == timestamp_nonexistent);
+ for (prerequisite_target& p: t.prerequisite_targets[a])
{
- if (pt != nullptr)
+ if (p == nullptr)
+ continue;
+
+ const target& pt (*p.target);
+
+ const auto& tc (pt[a].task_count);
+ if (tc.load (memory_order_acquire) >= busy)
+ ctx.sched.wait (exec, tc, scheduler::work_none);
+
+ target_state s (pt.executed_state (a));
+ rs |= s;
+
+ // Compare our timestamp to this prerequisite's.
+ //
+ if (!e)
{
- if (auto* e = pt->is_a<exe> ())
+ // If this is an mtime-based target, then compare timestamps.
+ //
+ if (const mtime_target* mpt = pt.is_a<mtime_target> ())
{
- if (auto* c = e->lookup_metadata<string> ("checksum"))
- {
- prog_cs.append (*c);
- }
+ if (mpt->newer (mt, s))
+ e = true;
+ }
+ else
+ {
+ // Otherwise we assume the prerequisite is newer if it was
+ // changed.
+ //
+ if (s == target_state::changed)
+ e = true;
+ }
+ }
+
+ if (p.adhoc)
+ p.target = nullptr; // Blank out.
+
+ // As part of this loop calculate checksums that need to include ad
+ // hoc prerequisites (unless the script tracks changes itself).
+ //
+ if (script.depdb_clear)
+ continue;
+
+ hash_target (pcs, pt);
+
+ // The script can reference a program in one of four ways:
+ //
+ // 1. As an (imported) target (e.g., $cli)
+ //
+ // 2. As a process_path_ex (e.g., $cxx.path).
+ //
+ // 3. As a builtin (e.g., sed)
+ //
+ // 4. As a program path/name.
+ //
+ // When it comes to change tracking, there is nothing we can do for
+ // (4) and there is nothing to do for (3) (assuming builtin semantics
+ // is stable/backwards-compatible). The (2) case is handled
+ // automatically by hashing all the variable values referenced by the
+ // script (see below), which in case of process_path_ex includes the
+ // checksum, if available.
+ //
+ // This leaves the (1) case, which itself splits into two sub-cases:
+ // the target comes with the dependency information (e.g., imported
+ // from a project via an export stub) or it does not (e.g., imported
+ // as installed). We don't need to do anything extra for the first
+ // sub-case since the target's state/mtime can be relied upon like any
+ // other prerequisite. Which cannot be said about the second sub-case,
+ // where we reply on checksum that may be included as part of the
+ // target metadata.
+ //
+ // So what we are going to do is hash checksum metadata of every
+ // executable prerequisite target that has it (we do it here in order
+ // to include ad hoc prerequisites, which feels like the right thing
+ // to do; the user may mark tools as ad hoc in order to omit them from
+ // $<).
+ //
+ if (auto* e = pt.is_a<exe> ())
+ {
+ if (auto* c = e->lookup_metadata<string> ("checksum"))
+ {
+ ecs.append (*c);
}
}
}
- }
- // Update prerequisites and determine if any of them render this target
- // out-of-date.
- //
- timestamp mt (t.load_mtime ());
- optional<target_state> ps (execute_prerequisites (a, t, mt));
+ if (!e)
+ ps = rs;
+ }
bool update (!ps);
@@ -598,7 +690,7 @@ namespace build2
// First should come the rule name/version.
//
- if (dd.expect ("adhoc 1") != nullptr)
+ if (dd.expect ("<ad hoc buildscript recipe> 1") != nullptr)
l4 ([&]{trace << "rule mismatch forcing update of " << t;});
// Then the script checksum.
@@ -667,13 +759,6 @@ namespace build2
// Target and prerequisite sets ($> and $<).
//
- // How should we hash them? We could hash them as target names (i.e., the
- // same as the $>/< content) or as paths (only for path-based targets).
- // While names feel more general, they are also more expensive to compute.
- // And for path-based targets, path is generally a good proxy for the
- // target name. Since the bulk of the ad hoc recipes will presumably be
- // operating exclusively on path-based targets, let's do it both ways.
- //
if (!script.depdb_clear)
{
auto hash = [ns = names ()] (sha256& cs, const target& t) mutable
@@ -691,16 +776,11 @@ namespace build2
sha256 tcs;
for (const target* m (&t); m != nullptr; m = m->adhoc_member)
- hash (tcs, *m);
+ hash_target (tcs, *m);
if (dd.expect (tcs.string ()) != nullptr)
l4 ([&]{trace << "target set change forcing update of " << t;});
- sha256 pcs;
- for (const target* pt: t.prerequisite_targets[a])
- if (pt != nullptr)
- hash (pcs, *pt);
-
if (dd.expect (pcs.string ()) != nullptr)
l4 ([&]{trace << "prerequisite set change forcing update of " << t;});
}
@@ -709,7 +789,7 @@ namespace build2
//
if (!script.depdb_clear)
{
- if (dd.expect (prog_cs.string ()) != nullptr)
+ if (dd.expect (ecs.string ()) != nullptr)
l4 ([&]{trace << "program checksum change forcing update of " << t;});
}