[llvm-branch-commits] [lldb] [lldb] Disable delayed-breakpoints by default for lldb 23 (PR #221250)

[David Spickett via llvm-branch-commits]

https://github.com/DavidSpickett created https://github.com/llvm/llvm-project/pull/221250

https://github.com/llvm/llvm-project/pull/192971 added a delayed breakpoints feature, which delays sending the breakpoint management packets until we actually continue the process. The feature itself is working, but it has made it easier to hit a bunch of pre-existing issues handling reads and writes around breakpoints.

https://github.com/llvm/llvm-project/issues/217359, https://github.com/llvm/llvm-project/issues/217840, https://github.com/llvm/llvm-project/issues/217359, https://github.com/llvm/llvm-project/issues/205120 and https://github.com/llvm/llvm-project/issues/202672 (reported by a downstream project as https://github.com/llvm/llvm-project/issues/216000)

These are all now fixed on the main branch, but it would be a large backport. Whereas this change is a single line.

delayed-breakpoints is purely a performance improvement, and users can opt into it by changing the setting.

This leaves the underlying bugs in place, but those bugs are not regressions in 23. They have been present for many years.

>From 95b3140820bb818fa95eef587dc2fbf532c5f9f0 Mon Sep 17 00:00:00 2001
From: David Spickett <david.spickett at arm.com>
Date: Fri, 4 Sep 2026 15:08:21 +0000
Subject: [PATCH] [lldb] Disable delayed-breakpoints by default for lldb 23

https://github.com/llvm/llvm-project/pull/192971 added a delayed
breakpoints feature, which delays sending the breakpoint management
packets until we actually continue the process. The feature itself
is working, but it has made it easier to hit a bunch of pre-existing
issues handling reads and writes around breakpoints.

https://github.com/llvm/llvm-project/issues/217359,
https://github.com/llvm/llvm-project/issues/217840,
https://github.com/llvm/llvm-project/issues/217359,
https://github.com/llvm/llvm-project/issues/205120 and
https://github.com/llvm/llvm-project/issues/202672
(reported by a downstream project as https://github.com/llvm/llvm-project/issues/216000)

These are all now fixed on the main branch, but it would
be a large backport to bring them over. Whereas this change
is a single line.

delayed-breakpoints is purely a performance improvement,
and users can opt into it by changing the setting.

This leaves the underlying bugs in place, but those
bugs are not regressions in 23. They have been present
for many years.
---
 lldb/source/Target/TargetProperties.td | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lldb/source/Target/TargetProperties.td b/lldb/source/Target/TargetProperties.td
index d63bc741e66ed..3003ac830c894 100644
--- a/lldb/source/Target/TargetProperties.td
+++ b/lldb/source/Target/TargetProperties.td
@@ -320,7 +320,7 @@ let Definition = "process", Path = "target.process" in {
              "threads are suspended during single-stepping operations.">;
   def UseDelayedBreakpoints
       : Property<"use-delayed-breakpoints", "Boolean">,
-        DefaultTrue,
+        DefaultFalse,
         Desc<"Specify whether updating breakpoints may be delayed until the "
              "process is about to resume.">;
 }