[clang] [llvm] Disentangle DISubprogram ODR type method uniquing from metadata uniquing (PR #217042)

[Kristina Bessonova via cfe-commits]

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@@ -0,0 +1,79 @@
+//===- llvm/IR/DebugInfoODRUniquer.cpp - Debug Information Builder --------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// Defines a class used to merge debug info for ODR types.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/IR/DebugInfoODRUniquer.h"
+#include "llvm/IR/DebugInfoMetadata.h"
+
+using namespace llvm;
+
+DISubprogram *DebugInfoODRUniquer::getODRSubprogramDecl(DIScope *Scope,
+                                                        StringRef LinkageName) {
+  // Only methods, which have a type scope, are eligable for ODR uniquing.
+  auto *CT = dyn_cast_or_null<DICompositeType>(Scope);
+  if (!CT || !CT->getRawIdentifier())
+    return nullptr;
+
+  auto R =
+      FnDecls.find_as(DISubprogramODRKey(CT->getIdentifier(), LinkageName));
+  if (R == FnDecls.end())
+    return nullptr;
+
+  assert(!(*R)->isDefinition() && "definition unexpectedly ODR-uniqued");
+  return *R;
+}
+
+void DebugInfoODRUniquer::addSubprogramDecl(DISubprogram *SP) {
+  assert(!SP->isDefinition() &&
+         "only expect declarations DISubprogram ODR uniquing");
+  assert(!SP->isDistinct() && "expect declarations to be uniqued");
+
+  if (SP->getLinkageName().empty())
+    return;
+  // Only methods, which have a type scope, are eligable for ODR uniquing.
+  auto *CT = dyn_cast_or_null<DICompositeType>(SP->getScope());
+  if (!CT || !CT->getRawIdentifier())
+    return;
+
+  FnDecls.insert(SP);
+}
+
+void DebugInfoODRUniquer::addUnresolvedODRSubprogramDecl(TempDISubprogram SP) {
+  assert(!SP->isDefinition() && "expected declarations only");
+  if (SP->getLinkageName().empty())
+    return;
+  PendingFnDecls.push_back(std::move(SP));
+}
+
+void DebugInfoODRUniquer::finalizeUnresolvedSubprogramDecls() {
+  for (auto It = PendingFnDecls.begin(), End = PendingFnDecls.end(); It != End;
+       ++It) {
+    TempDISubprogram SP = std::move(*It);
+    if (MDNode *Scope = dyn_cast_or_null<MDNode>(SP->getRawScope())) {
+      assert(!SP->getLinkageName().empty() && "expcted linkage name");
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chbessonova wrote:

typo: expcted -> expected

https://github.com/llvm/llvm-project/pull/217042