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authorBoris Kolpackov <boris@codesynthesis.com>2017-03-04 18:24:52 +0200
committerBoris Kolpackov <boris@codesynthesis.com>2017-03-04 18:24:52 +0200
commit223b0fe6edda5ea3da1110c7d4e0c62575bd55fa (patch)
treef705061171bf44581ced527d9f52adf27de05017 /build2
parente27a91c9e3fccf52d39afb23c6dbdff117adfd5f (diff)
Fix match-only recipe override corner case
Diffstat (limited to 'build2')
-rw-r--r--build2/algorithm.cxx135
1 files changed, 82 insertions, 53 deletions
diff --git a/build2/algorithm.cxx b/build2/algorithm.cxx
index 51877b3..032d657 100644
--- a/build2/algorithm.cxx
+++ b/build2/algorithm.cxx
@@ -834,46 +834,65 @@ namespace build2
// Try to atomically change applied to busy. Note that we are in the
// execution phase so the target shall not be spin-locked.
//
- size_t tc (target::count_applied ());
- if (t.task_count.compare_exchange_strong (
- tc,
- target::count_busy (),
- memory_order_acq_rel, // Synchronize on success.
- memory_order_acquire)) // Synchronize on failure.
+ size_t matc (target::count_matched ());
+ size_t exec (target::count_executed ());
+ size_t busy (target::count_busy ());
+
+ for (size_t tc (target::count_applied ());;)
{
- if (t.state_ != target_state::unchanged) // Noop recipe.
+ if (t.task_count.compare_exchange_strong (
+ tc,
+ busy,
+ memory_order_acq_rel, // Synchronize on success.
+ memory_order_acquire)) // Synchronize on failure.
{
- if (task_count == nullptr)
- return execute_impl (a, t);
-
- // Pass our diagnostics stack (this is safe since we expect the caller
- // to wait for completion before unwinding its diag stack).
+ // Overriden match-only or noop recipe.
//
- if (sched.async (start_count,
- *task_count,
- [a] (target& t, const diag_frame* ds)
- {
- diag_frame df (ds);
- execute_impl (a, t); // Note: noexcept.
- },
- ref (t),
- diag_frame::stack))
- return target_state::unknown; // Queued.
-
- // Executed synchronously, fall through.
+ if (tc == matc || t.state_ == target_state::unchanged)
+ {
+ t.state_ = target_state::unchanged;
+ t.task_count.store (exec, memory_order_release);
+ sched.resume (t.task_count);
+ }
+ else
+ {
+ if (task_count == nullptr)
+ return execute_impl (a, t);
+
+ // Pass our diagnostics stack (this is safe since we expect the
+ // caller to wait for completion before unwinding its diag stack).
+ //
+ if (sched.async (start_count,
+ *task_count,
+ [a] (target& t, const diag_frame* ds)
+ {
+ diag_frame df (ds);
+ execute_impl (a, t); // Note: noexcept.
+ },
+ ref (t),
+ diag_frame::stack))
+ return target_state::unknown; // Queued.
+
+ // Executed synchronously, fall through.
+ }
}
else
{
- t.task_count.store (target::count_executed (), memory_order_release);
- sched.resume (t.task_count);
+ // Normally either busy or already executed.
+ //
+ if (tc >= busy) return target_state::busy;
+ else if (tc != exec)
+ {
+ // This can happen is we matched (a noop) recipe which then got
+ // overridden as part of group resolution but not all the way to
+ // applied. In this case we treat it as noop.
+ //
+ assert (tc == matc && t.action > a);
+ continue;
+ }
}
- }
- else
- {
- // Should be either busy or already executed.
- //
- if (tc >= target::count_busy ()) return target_state::busy;
- else assert (tc == target::count_executed ());
+
+ break;
}
return t.executed_state (false);
@@ -884,32 +903,42 @@ namespace build2
{
target& t (const_cast<target&> (ct)); // MT-aware.
- size_t busy (target::count_busy ());
+ // Similar logic to match() above.
+ //
+ size_t matc (target::count_matched ());
size_t exec (target::count_executed ());
+ size_t busy (target::count_busy ());
- size_t tc (target::count_applied ());
- if (t.task_count.compare_exchange_strong (
- tc,
- busy,
- memory_order_acq_rel, // Synchronize on success.
- memory_order_acquire)) // Synchronize on failure.
+ for (size_t tc (target::count_applied ());;)
{
- if (t.state_ != target_state::unchanged) // Noop recipe.
- execute_impl (a, t);
- else
+ if (t.task_count.compare_exchange_strong (
+ tc,
+ busy,
+ memory_order_acq_rel, // Synchronize on success.
+ memory_order_acquire)) // Synchronize on failure.
{
- t.task_count.store (exec, memory_order_release);
- sched.resume (t.task_count);
+ if (tc == matc || t.state_ == target_state::unchanged)
+ {
+ t.state_ = target_state::unchanged;
+ t.task_count.store (exec, memory_order_release);
+ sched.resume (t.task_count);
+ }
+ else
+ execute_impl (a, t);
}
- }
- else
- {
- // If the target is busy, wait for it.
- //
- if (tc >= busy)
- sched.wait (exec, t.task_count, scheduler::work_none);
else
- assert (tc == exec);
+ {
+ // If the target is busy, wait for it.
+ //
+ if (tc >= busy) sched.wait (exec, t.task_count, scheduler::work_none);
+ else if (tc != exec)
+ {
+ assert (tc == matc && t.action > a);
+ continue;
+ }
+ }
+
+ break;
}
return t.executed_state ();