[llvm-branch-commits] [llvm] release/19.x: [DebugInfo][RemoveDIs] Find types hidden in DbgRecords (#106547) (PR #107060)

[via llvm-branch-commits]

https://github.com/llvmbot created https://github.com/llvm/llvm-project/pull/107060

Backport 25f87f2d703178bb4bc13a62cb3df001b186cba2

Requested by: @jmorse

>From e832641a6370eebfd0d57ed4c4224dc1842bb0c8 Mon Sep 17 00:00:00 2001
From: Jeremy Morse <jeremy.morse at sony.com>
Date: Mon, 2 Sep 2024 11:56:40 +0100
Subject: [PATCH] [DebugInfo][RemoveDIs] Find types hidden in DbgRecords
 (#106547)
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When serialising to textual IR, there can be constant Values referred to
by DbgRecords that don't appear anywhere else, and have types hidden
even deeper in side them. Enumerate these when enumerating all types.

Test by Mikael Holmén.

(cherry picked from commit 25f87f2d703178bb4bc13a62cb3df001b186cba2)
---
 llvm/lib/IR/DebugProgramInstruction.cpp       |  5 +-
 llvm/lib/IR/TypeFinder.cpp                    | 14 +++++
 .../DebugInfo/type-finder-w-dbg-records.ll    | 51 +++++++++++++++++++
 3 files changed, 68 insertions(+), 2 deletions(-)
 create mode 100644 llvm/test/DebugInfo/type-finder-w-dbg-records.ll

diff --git a/llvm/lib/IR/DebugProgramInstruction.cpp b/llvm/lib/IR/DebugProgramInstruction.cpp
index 362d467beeb11b..5d2189b54204fb 100644
--- a/llvm/lib/IR/DebugProgramInstruction.cpp
+++ b/llvm/lib/IR/DebugProgramInstruction.cpp
@@ -473,11 +473,12 @@ DbgLabelRecord::createDebugIntrinsic(Module *M,
 
 Value *DbgVariableRecord::getAddress() const {
   auto *MD = getRawAddress();
-  if (auto *V = dyn_cast<ValueAsMetadata>(MD))
+  if (auto *V = dyn_cast_or_null<ValueAsMetadata>(MD))
     return V->getValue();
 
   // When the value goes to null, it gets replaced by an empty MDNode.
-  assert(!cast<MDNode>(MD)->getNumOperands() && "Expected an empty MDNode");
+  assert(!MD ||
+         !cast<MDNode>(MD)->getNumOperands() && "Expected an empty MDNode");
   return nullptr;
 }
 
diff --git a/llvm/lib/IR/TypeFinder.cpp b/llvm/lib/IR/TypeFinder.cpp
index 003155a4af4877..963f4b4806e1f9 100644
--- a/llvm/lib/IR/TypeFinder.cpp
+++ b/llvm/lib/IR/TypeFinder.cpp
@@ -88,6 +88,20 @@ void TypeFinder::run(const Module &M, bool onlyNamed) {
         for (const auto &MD : MDForInst)
           incorporateMDNode(MD.second);
         MDForInst.clear();
+
+        // Incorporate types hiding in variable-location information.
+        for (const auto &Dbg : I.getDbgRecordRange()) {
+          // Pick out records that have Values.
+          if (const DbgVariableRecord *DVI =
+                  dyn_cast<DbgVariableRecord>(&Dbg)) {
+            for (Value *V : DVI->location_ops())
+              incorporateValue(V);
+            if (DVI->isDbgAssign()) {
+              if (Value *Addr = DVI->getAddress())
+                incorporateValue(Addr);
+            }
+          }
+        }
       }
   }
 
diff --git a/llvm/test/DebugInfo/type-finder-w-dbg-records.ll b/llvm/test/DebugInfo/type-finder-w-dbg-records.ll
new file mode 100644
index 00000000000000..8259b4a9f1c3a5
--- /dev/null
+++ b/llvm/test/DebugInfo/type-finder-w-dbg-records.ll
@@ -0,0 +1,51 @@
+; RUN: opt --passes=verify %s -o - -S | FileCheck %s
+
+;; Test that the type definitions are discovered when serialising to LLVM-IR,
+;; even if they're only present inside a DbgRecord, and thus not normally
+;; visible.
+
+; CHECK: %union.anon = type { %struct.a }
+; CHECK: %struct.a = type { i32 }
+; CHECK: %union.anon2 = type { %struct.a2 }
+; CHECK: %struct.a2 = type { i32 }
+
+; ModuleID = 'bbi-98372.ll'
+source_filename = "bbi-98372.ll"
+
+%union.anon = type { %struct.a }
+%struct.a = type { i32 }
+%union.anon2 = type { %struct.a2 }
+%struct.a2 = type { i32 }
+
+ at d = global [1 x { i16, i16 }] [{ i16, i16 } { i16 0, i16 undef }], align 1
+ at e = global [1 x { i16, i16 }] [{ i16, i16 } { i16 0, i16 undef }], align 1
+
+define void @f() {
+entry:
+    #dbg_value(ptr getelementptr inbounds ([1 x %union.anon], ptr @d, i32 0, i32 3), !7, !DIExpression(), !14)
+    #dbg_assign(ptr null, !7, !DIExpression(), !16, ptr getelementptr inbounds ([1 x %union.anon2], ptr @e, i32 0, i32 3), !17, !14)
+  ret void, !dbg !15
+}
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!2, !3, !4, !5}
+!llvm.ident = !{!6}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C11, file: !1, producer: "clang", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, splitDebugInlining: false, nameTableKind: None)
+!1 = !DIFile(filename: "foo.c", directory: "/bar")
+!2 = !{i32 7, !"Dwarf Version", i32 4}
+!3 = !{i32 2, !"Debug Info Version", i32 3}
+!4 = !{i32 1, !"wchar_size", i32 1}
+!5 = !{i32 7, !"frame-pointer", i32 2}
+!6 = !{!"clang"}
+!7 = !DILocalVariable(name: "f", scope: !8, file: !1, line: 8, type: !12)
+!8 = distinct !DISubprogram(name: "e", scope: !1, file: !1, line: 8, type: !9, scopeLine: 8, flags: DIFlagAllCallsDescribed, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0, retainedNodes: !11)
+!9 = !DISubroutineType(types: !10)
+!10 = !{null}
+!11 = !{!7}
+!12 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !13, size: 16)
+!13 = !DIBasicType(name: "int", size: 16, encoding: DW_ATE_signed)
+!14 = !DILocation(line: 0, scope: !8)
+!15 = !DILocation(line: 8, column: 28, scope: !8)
+!16 = distinct !DIAssignID()
+!17 = !DIExpression()