From a5a8a05c78c0d1298c4128aaafd0275354198afb Mon Sep 17 00:00:00 2001
From: Felipe de Azevedo Piovezan <fpiovezan@apple.com>
Date: Wed, 3 Aug 2022 14:09:04 -0400
Subject: [PATCH] [SelectionDAG] Handle IntToPtr constants in dbg.value

The function `handleDebugValue` has custom logic to handle certain kinds
constants, namely integers, floats and null pointers. However, it does
not handle constant pointers created from IntToPtr ConstantExpressions.
This patch addresses the issue by replacing the Constant with its
integer operand.

A similar bug was addressed for GlobalISel in D130642.

Reviewed By: aprantl, #debug-info

Differential Revision: https://reviews.llvm.org/D130908
---
 .../SelectionDAG/SelectionDAGBuilder.cpp      |  7 ++++++
 .../CodeGen/AArch64/inttoptr_debug_value.ll   | 25 +++++++++++++++++++
 2 files changed, 32 insertions(+)
 create mode 100644 llvm/test/CodeGen/AArch64/inttoptr_debug_value.ll

diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
index 2239148bf447..40b3f683f56b 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
@@ -1344,6 +1344,13 @@ bool SelectionDAGBuilder::handleDebugValue(ArrayRef<const Value *> Values,
       continue;
     }
 
+    // Look through IntToPtr constants.
+    if (auto *CE = dyn_cast<ConstantExpr>(V))
+      if (CE->getOpcode() == Instruction::IntToPtr) {
+        LocationOps.emplace_back(SDDbgOperand::fromConst(CE->getOperand(0)));
+        continue;
+      }
+
     // If the Value is a frame index, we can create a FrameIndex debug value
     // without relying on the DAG at all.
     if (const AllocaInst *AI = dyn_cast<AllocaInst>(V)) {
diff --git a/llvm/test/CodeGen/AArch64/inttoptr_debug_value.ll b/llvm/test/CodeGen/AArch64/inttoptr_debug_value.ll
new file mode 100644
index 000000000000..5ff5292c0e73
--- /dev/null
+++ b/llvm/test/CodeGen/AArch64/inttoptr_debug_value.ll
@@ -0,0 +1,25 @@
+; RUN: llc -o - --print-after-isel %s 2>&1 | FileCheck %s
+
+target triple = "arm64-apple-ios13.4.0"
+define void @foo() !dbg !6 {
+  ; CHECK: DBG_VALUE 42, $noreg, !"myvar", !DIExpression()
+  call void @llvm.dbg.value(metadata ptr inttoptr (i64 42 to ptr), metadata !9, metadata !DIExpression()), !dbg !11
+  ret void
+}
+
+declare void @llvm.dbg.value(metadata, metadata, metadata)
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!5}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C, file: !1, producer: "debugify", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !2)
+!1 = !DIFile(filename: "t.ll", directory: "/")
+!2 = !{}
+!5 = !{i32 4, !"Debug Info Version", i32 3}
+!6 = distinct !DISubprogram(name: "foo", linkageName: "foo", scope: null, file: !1, line: 1, type: !7, scopeLine: 1, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0, retainedNodes: !8)
+!7 = !DISubroutineType(types: !2)
+!8 = !{!9}
+!9 = !DILocalVariable(name: "myvar", scope: !6, file: !1, line: 1, type: !10)
+!10 = !DIBasicType(name: "ty64", size: 64, encoding: DW_ATE_unsigned)
+!11 = !DILocation(line: 1, column: 1, scope: !6)
+!12 = !DILocation(line: 2, column: 1, scope: !6)