From cc885f9b24be46d84f4ba8e78a066174f3e010c6 Mon Sep 17 00:00:00 2001
From: Dmitry Petrov <dmitry.petrov@jetbrains.com>
Date: Tue, 28 Sep 2021 18:03:17 +0300
Subject: [PATCH] JVM don't remove NOP starting a try-catch block

---
 .../TemporaryVariablesEliminationTransformer.kt              | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/compiler/backend/src/org/jetbrains/kotlin/codegen/optimization/temporaryVals/TemporaryVariablesEliminationTransformer.kt b/compiler/backend/src/org/jetbrains/kotlin/codegen/optimization/temporaryVals/TemporaryVariablesEliminationTransformer.kt
index 8c5ba89e5b0..b842a1e754f 100644
--- a/compiler/backend/src/org/jetbrains/kotlin/codegen/optimization/temporaryVals/TemporaryVariablesEliminationTransformer.kt
+++ b/compiler/backend/src/org/jetbrains/kotlin/codegen/optimization/temporaryVals/TemporaryVariablesEliminationTransformer.kt
@@ -37,7 +37,6 @@ class TemporaryVariablesEliminationTransformer(private val state: GenerationStat
         methodNode.removeUnusedLocalVariables()
     }
 
-
     private fun simplifyTrivialInstructions(methodNode: MethodNode) {
         val insnList = methodNode.instructions
         for (insn in insnList.toArray()) {
@@ -61,12 +60,14 @@ class TemporaryVariablesEliminationTransformer(private val state: GenerationStat
                 }
             }
         }
+        val tcbStartLabels = methodNode.tryCatchBlocks.mapTo(HashSet()) { it.start }
         for (insn in insnList.toArray()) {
             // Remove NOPs immediately preceded or immediately followed by an instruction that does something
             // - not a LINENUMBER, not a LABEL, and not a FRAME.
             if (insn.opcode == Opcodes.NOP) {
-                val next = insn.next
                 val prev = insn.previous
+                if (prev in tcbStartLabels) continue
+                val next = insn.next
                 if (next != null && next.isMeaningful || prev != null && prev.isMeaningful) {
                     insnList.remove(insn)
                 }