[IR/Verifier] Each DISubprogram with isDefinition: true must belong to a CU.

Add a check to catch violations. ~60 tests were broken and prevented
this change to be committed. Adrian and I (thanks Adrian!) went
through them in the last week or so updating. The check can be
done more efficiently but I'd still like to get this in ASAP to
avoid more broken tests to be checked in (if any).

PR:  27101
llvm-svn: 266102

Author: dcci

llvm/lib/IR/Verifier.cpp

@@ -1011,6 +1011,22 @@ void Verifier::visitDISubprogram(const DISubprogram &N) {
 
   if (N.isDefinition())
     Assert(N.isDistinct(), "subprogram definitions must be distinct", &N);
+
+  // Ensure that every DISubprogram with isDefinition: true belongs
+  // to a DICompileUnit.
+  // FIXME: This is a very inefficient way of handling the problem.
+  // Use a SmallSetPtr which contains the Listed DISubprograms in the CU
+  // instead.
+  if (N.isDefinition()) {
+    auto *CUs = M->getNamedMetadata("llvm.dbg.cu");
+    Assert(CUs, "subprogram must belong to a compile unit", &N);
+    for (auto *CU : CUs->operands())
+      if (auto Subprograms = cast<DICompileUnit>(CU)->getSubprograms())
+        for (const auto *Sp : Subprograms)
+          if (Sp == &N)
+            return;
+    Assert(false, "subprogram not found in any compile unit", &N);
+  }
 }
 
 void Verifier::visitDILexicalBlockBase(const DILexicalBlockBase &N) {

llvm/test/Verifier/disubprogram-nocu.ll

@@ -0,0 +1,22 @@
+; Reject if DISubprogram does not belong to a DICompileUnit.
+; RUN: not llvm-as %s
+
+@_ZZNK4llvm6object15MachOObjectFile21getRelocationTypeNameENS0_11DataRefImplERNS_15SmallVectorImplIcEEE5Table = external unnamed_addr constant [6 x i8*], align 16
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!13}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !1, isOptimized: false, runtimeVersion: 0, emissionKind: 0, globals: !2, imports: !9)
+!1 = !DIFile(filename: "../lib/Object/MachOObjectFile.cpp", directory: "/home/davide/work/llvm/build-lto-debug")
+!2 = !{!3, !8}
+!3 = !DIGlobalVariable(name: "Table", scope: !4, isLocal: false, isDefinition: true, variable: [6 x i8*]* @_ZZNK4llvm6object15MachOObjectFile21getRelocationTypeNameENS0_11DataRefImplERNS_15SmallVectorImplIcEEE5Table)
+!4 = distinct !DILexicalBlock(scope: !5, line: 722, column: 23)
+!5 = distinct !DILexicalBlock(scope: !6, line: 721, column: 17)
+!6 = distinct !DISubprogram(name: "getRelocationTypeName", scope: null, isLocal: false, isDefinition: true, isOptimized: false, variables: !7)
+!7 = !{}
+!8 = !DIGlobalVariable(name: "IsLittleEndianHost", scope: null, isLocal: false, isDefinition: true, variable: i1 true)
+!9 = !{!10, !12}
+!10 = !DIImportedEntity(tag: DW_TAG_imported_declaration, scope: !11, line: 121)
+!11 = !DINamespace(name: "std", scope: null, line: 1967)
+!12 = !DIImportedEntity(tag: DW_TAG_imported_module, scope: !0, line: 32)
+!13 = !{i32 2, !"Debug Info Version", i32 3}