From 794edc81d0b72fa644ac4a6d9b9656e960c68fb8 Mon Sep 17 00:00:00 2001
From: Matthew Lugg <mlugg@mlugg.co.uk>
Date: Wed, 15 Apr 2026 23:53:39 +0100
Subject: [PATCH] Zcu.PerThread: make debug logs less noisy

I often go through these logs when debugging issues with incremental
compilation, but the first thing I do is always comment out some of
these lines, because they're just way too noisy. I don't need to know
every time Sema checks that a unit is up-to-date, I only care when
things actually get analyzed! This decreases the size of
`--debug-log zcu` by an order of magnitude (or more) in most cases.
---
 src/Zcu/PerThread.zig | 22 +++++++---------------
 1 file changed, 7 insertions(+), 15 deletions(-)

diff --git a/src/Zcu/PerThread.zig b/src/Zcu/PerThread.zig
index 7d7e029041..9bf1f3a3e3 100644
--- a/src/Zcu/PerThread.zig
+++ b/src/Zcu/PerThread.zig
@@ -1073,8 +1073,6 @@ pub fn ensureMemoizedStateUpToDate(
 
     const unit: AnalUnit = .wrap(.{ .memoized_state = stage });
 
-    log.debug("ensureMemoizedStateUpToDate", .{});
-
     assert(!zcu.analysis_in_progress.contains(unit));
 
     const was_outdated = zcu.clearOutdatedState(unit);
@@ -1142,6 +1140,8 @@ fn analyzeMemoizedState(
     const comp = zcu.comp;
     const gpa = comp.gpa;
 
+    log.debug("analyzeMemoizedState({t})", .{stage});
+
     const unit: AnalUnit = .wrap(.{ .memoized_state = stage });
 
     try zcu.analysis_in_progress.putNoClobber(gpa, unit, reason);
@@ -1182,8 +1182,6 @@ pub fn ensureComptimeUnitUpToDate(pt: Zcu.PerThread, cu_id: InternPool.ComptimeU
 
     const anal_unit: AnalUnit = .wrap(.{ .@"comptime" = cu_id });
 
-    log.debug("ensureComptimeUnitUpToDate {f}", .{zcu.fmtAnalUnit(anal_unit)});
-
     assert(!zcu.analysis_in_progress.contains(anal_unit));
 
     // Determine whether or not this `ComptimeUnit` is outdated. For this kind of `AnalUnit`, that's
@@ -1345,8 +1343,6 @@ pub fn ensureTypeLayoutUpToDate(
 
     const anal_unit: AnalUnit = .wrap(.{ .type_layout = ty.toIntern() });
 
-    log.debug("ensureTypeLayoutUpToDate {f}", .{zcu.fmtAnalUnit(anal_unit)});
-
     assert(!zcu.analysis_in_progress.contains(anal_unit));
 
     const was_outdated: bool = outdated: {
@@ -1413,6 +1409,8 @@ pub fn ensureTypeLayoutUpToDate(
     };
     defer sema.deinit();
 
+    log.debug("ensureTypeLayoutUpToDate {f} (out of date, resolving)", .{zcu.fmtAnalUnit(anal_unit)});
+
     const result = switch (ty.zigTypeTag(zcu)) {
         .@"enum" => Sema.type_resolution.resolveEnumLayout(&sema, ty),
         .@"struct" => Sema.type_resolution.resolveStructLayout(&sema, ty),
@@ -1478,8 +1476,6 @@ pub fn ensureStructDefaultsUpToDate(
 
     const anal_unit: AnalUnit = .wrap(.{ .struct_defaults = ty.toIntern() });
 
-    log.debug("ensureStructDefaultsUpToDate {f}", .{zcu.fmtAnalUnit(anal_unit)});
-
     assert(!zcu.analysis_in_progress.contains(anal_unit));
 
     const was_outdated: bool = outdated: {
@@ -1536,6 +1532,8 @@ pub fn ensureStructDefaultsUpToDate(
     };
     defer sema.deinit();
 
+    log.debug("ensureStructDefaultsUpToDate {f} (out of date, resolving)", .{zcu.fmtAnalUnit(anal_unit)});
+
     const new_failed: bool = if (Sema.type_resolution.resolveStructDefaults(&sema, ty)) failed: {
         break :failed false;
     } else |err| switch (err) {
@@ -1584,8 +1582,6 @@ pub fn ensureNavValUpToDate(
     const anal_unit: AnalUnit = .wrap(.{ .nav_val = nav_id });
     const nav = ip.getNav(nav_id);
 
-    log.debug("ensureNavValUpToDate {f}", .{zcu.fmtAnalUnit(anal_unit)});
-
     assert(!zcu.analysis_in_progress.contains(anal_unit));
 
     try zcu.ensureNavValAnalysisQueued(nav_id);
@@ -1946,8 +1942,6 @@ pub fn ensureNavTypeUpToDate(
     const anal_unit: AnalUnit = .wrap(.{ .nav_ty = nav_id });
     const nav = ip.getNav(nav_id);
 
-    log.debug("ensureNavTypeUpToDate {f}", .{zcu.fmtAnalUnit(anal_unit)});
-
     assert(!zcu.analysis_in_progress.contains(anal_unit));
 
     try zcu.ensureNavValAnalysisQueued(nav_id);
@@ -2191,8 +2185,6 @@ pub fn ensureFuncBodyUpToDate(
 
     const anal_unit: AnalUnit = .wrap(.{ .func = func_index });
 
-    log.debug("ensureFuncBodyUpToDate {f}", .{zcu.fmtAnalUnit(anal_unit)});
-
     assert(!zcu.analysis_in_progress.contains(anal_unit));
 
     const func = zcu.funcInfo(func_index);
@@ -2282,7 +2274,7 @@ fn analyzeFuncBody(
     else
         .none;
 
-    log.debug("analyze and generate fn body {f}", .{zcu.fmtAnalUnit(anal_unit)});
+    log.debug("analyzeFuncBody {f}", .{zcu.fmtAnalUnit(anal_unit)});
 
     var air = try pt.analyzeFuncBodyInner(func_index, reason);
     var air_owned = true;