[JVM_IR] Fix line number information for try-catch.

In particular, the current line numbers could lead to stepping
into the catch handler even when the code in the try did not
throw an exception.

This was caused by the code materializing the final value having
the catch line number. This patch delays the materialization
until the line number of the usage has been emitted.

compiler/ir/backend.jvm/src/org/jetbrains/kotlin/backend/jvm/codegen/ExpressionCodegen.kt

@@ -495,8 +495,9 @@ class ExpressionCodegen(
 
         val initializer = declaration.initializer
         if (initializer != null) {
-            initializer.accept(this, data).materializeAt(varType, declaration.type)
+            var value = initializer.accept(this, data)
             initializer.markLineNumber(startOffset = true)
+            value.materializeAt(varType, declaration.type)
             mv.store(index, varType)
         } else if (declaration.isVisibleInLVT) {
             pushDefaultValueOnStack(varType, mv)
@@ -980,14 +981,24 @@ class ExpressionCodegen(
         }
 
         mv.mark(tryCatchBlockEnd)
-
         // TODO: generate a common `finally` for try & catch blocks here? Right now this breaks the inliner.
-        if (savedValue != null) {
-            mv.load(savedValue, tryAsmType)
-            frameMap.leaveTemp(tryAsmType)
-            return aTry.onStack
+        return object : PromisedValue(this, tryAsmType, aTry.type) {
+            override fun materializeAt(target: Type, irTarget: IrType) {
+                if (savedValue != null) {
+                    mv.load(savedValue, tryAsmType)
+                    frameMap.leaveTemp(tryAsmType)
+                    super.materializeAt(target, irTarget)
+                } else {
+                    unitValue.materializeAt(target, irTarget)
+                }
+            }
+
+            override fun discard() {
+                if (savedValue != null) {
+                    frameMap.leaveTemp(tryAsmType)
+                }
+            }
         }
-        return unitValue
     }
 
     private fun genTryCatchCover(catchStart: Label, tryStart: Label, tryEnd: Label, tryGaps: List<Pair<Label, Label>>, type: String?) {

compiler/testData/debug/stepping/tryCatchExpression.kt

@@ -12,10 +12,17 @@ fun foo() {
     } catch (e: Throwable) {
         return
     }
+
+    val x = try {
+        mightThrow3()
+    } catch (e: Throwable) {
+        return
+    }
 }
 
 var throw1 = false
 var throw2 = false
+var throw3 = false
 
 fun mightThrow() {
     if (throw1) throw Exception()
@@ -25,7 +32,14 @@ fun mightThrow2() {
     if (throw2) throw Exception()
 }
 
+fun mightThrow3(): Int {
+    if (throw3) throw Exception()
+    return 42
+}
+
 fun box() {
+    foo()
+    throw3 = true
     foo()
     throw2 = true
     foo()
@@ -33,41 +47,61 @@ fun box() {
     foo()
 }
 
-// IGNORE_BACKEND: JVM_IR
-// The JVM_IR backend will stop on line 13 even when mightThrow2
-// does not throw!
-
 // LINENUMBERS
-// test.kt:29 box
+// test.kt:41 box
 // test.kt:4 foo
 // test.kt:5 foo
-// test.kt:21 mightThrow
-// test.kt:22 mightThrow
+// test.kt:28 mightThrow
+// test.kt:29 mightThrow
 // test.kt:5 foo
 // test.kt:10 foo
 // test.kt:11 foo
-// test.kt:25 mightThrow2
-// test.kt:26 mightThrow2
+// test.kt:32 mightThrow2
+// test.kt:33 mightThrow2
 // test.kt:11 foo
 // test.kt:10 foo
-// test.kt:15 foo
-// test.kt:30 box
-// test.kt:31 box
+// test.kt:16 foo
+// test.kt:17 foo
+// test.kt:36 mightThrow3
+// test.kt:37 mightThrow3
+// test.kt:17 foo
+// test.kt:16 foo
+// test.kt:21 foo
+// test.kt:42 box
+// test.kt:43 box
 // test.kt:4 foo
 // test.kt:5 foo
-// test.kt:21 mightThrow
-// test.kt:22 mightThrow
+// test.kt:28 mightThrow
+// test.kt:29 mightThrow
 // test.kt:5 foo
 // test.kt:10 foo
 // test.kt:11 foo
-// test.kt:25 mightThrow2
+// test.kt:32 mightThrow2
+// test.kt:33 mightThrow2
+// test.kt:11 foo
+// test.kt:10 foo
+// test.kt:16 foo
+// test.kt:17 foo
+// test.kt:36 mightThrow3
+// test.kt:18 foo
+// test.kt:19 foo
+// test.kt:44 box
+// test.kt:45 box
+// test.kt:4 foo
+// test.kt:5 foo
+// test.kt:28 mightThrow
+// test.kt:29 mightThrow
+// test.kt:5 foo
+// test.kt:10 foo
+// test.kt:11 foo
+// test.kt:32 mightThrow2
 // test.kt:12 foo
 // test.kt:13 foo
-// test.kt:32 box
-// test.kt:33 box
+// test.kt:46 box
+// test.kt:47 box
 // test.kt:4 foo
 // test.kt:5 foo
-// test.kt:21 mightThrow
+// test.kt:28 mightThrow
 // test.kt:6 foo
 // test.kt:7 foo
-// test.kt:34 box
+// test.kt:48 box

compiler/testData/debug/stepping/tryCatchFinally.kt

@@ -37,10 +37,6 @@ fun box() {
     foo()
 }
 
-// IGNORE_BACKEND: JVM_IR
-// The JVM_IR backend goes back to line 17 after line 18. It has the
-// sequence 17, 18, 17 which doesn't make sense.
-
 // LINENUMBERS
 // test.kt:33 box
 // test.kt:4 foo

compiler/testData/debug/stepping/tryFinally.kt

@@ -34,9 +34,10 @@ fun box() {
     foo()
 }
 
-// IGNORE_BACKEND: JVM_IR
-// The JVM_IR backend goes back to line 13 after line 14. It has the
-// sequence 13, 14, 13 which doesn't make sense.
+// The JVM backend steps back to line 11 when leaving the
+// `mightThrow2` call. The JVM_IR backend does not. The
+// JVM_IR behavior is consistent with what happens for the
+// try-finally where the value is discarded which seems good.
 
 // LINENUMBERS
 // test.kt:29 box
@@ -50,7 +51,9 @@ fun box() {
 // test.kt:11 foo
 // test.kt:25 mightThrow2
 // test.kt:26 mightThrow2
+// LINENUMBERS JVM
 // test.kt:11 foo
+// LINENUMBERS
 // test.kt:13 foo
 // test.kt:14 foo
 // test.kt:10 foo