Add pseudo-instruction `Ladjust_trap_depth` (#2322)

Ladjust_trap_depth replaces dummy Lpushtrap generated in linearize of
Iexit to notify assembler generation about updates to the
stack. Ladjust_trap_depth is used to keep the virtual stack pointer in
sync and emit dwarf information, without emitting any assembly
instructions. It therefore avoids generating dead code.

This patch is extract from PR1482 @lthls

1 files changed, 4 insertions, 0 deletions

diff --git a/Changes b/Changes
index 65750fb44a..bc485a5daa 100644
--- a/Changes
+++ b/Changes
@@ -31,6 +31,10 @@ Working version
 - #8672: Optimise Switch code generation on booleans.
   (Stephen Dolan, review by Pierre Chambart)
 
+- #2322: Add pseudo-instruction `Ladjust_trap_depth` to replace
+  dummy Lpushtrap generated in linearize
+  (Greta Yorsh and Vincent Laviron, review by Xavier Leroy)
+
 ### Runtime system:
 
 - #8619: Ensure Gc.minor_words remains accurate after a GC.