diff --git a/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp b/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
index 6eee8c5..ecc35b4 100644
--- a/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
+++ b/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
@@ -629,6 +629,7 @@
   auto *SP = cast<DISubprogram>(Scope->getScopeNode());
 
   DIE *ContextDIE;
+  DwarfCompileUnit *ContextCU = this;
 
   if (includeMinimalInlineScopes())
     ContextDIE = &getUnitDie();
@@ -639,18 +640,23 @@
   else if (auto *SPDecl = SP->getDeclaration()) {
     ContextDIE = &getUnitDie();
     getOrCreateSubprogramDIE(SPDecl);
-  } else
+  } else {
     ContextDIE = getOrCreateContextDIE(resolve(SP->getScope()));
+    // The scope may be shared with a subprogram that has already been
+    // constructed in another CU, in which case we need to construct this
+    // subprogram in the same CU.
+    ContextCU = DD->lookupCU(ContextDIE->getUnitDie());
+  }
 
   // Passing null as the associated node because the abstract definition
   // shouldn't be found by lookup.
-  AbsDef = &createAndAddDIE(dwarf::DW_TAG_subprogram, *ContextDIE, nullptr);
-  applySubprogramAttributesToDefinition(SP, *AbsDef);
+  AbsDef = &ContextCU->createAndAddDIE(dwarf::DW_TAG_subprogram, *ContextDIE, nullptr);
+  ContextCU->applySubprogramAttributesToDefinition(SP, *AbsDef);
 
-  if (!includeMinimalInlineScopes())
-    addUInt(*AbsDef, dwarf::DW_AT_inline, None, dwarf::DW_INL_inlined);
-  if (DIE *ObjectPointer = createAndAddScopeChildren(Scope, *AbsDef))
-    addDIEEntry(*AbsDef, dwarf::DW_AT_object_pointer, *ObjectPointer);
+  if (!ContextCU->includeMinimalInlineScopes())
+    ContextCU->addUInt(*AbsDef, dwarf::DW_AT_inline, None, dwarf::DW_INL_inlined);
+  if (DIE *ObjectPointer = ContextCU->createAndAddScopeChildren(Scope, *AbsDef))
+    ContextCU->addDIEEntry(*AbsDef, dwarf::DW_AT_object_pointer, *ObjectPointer);
 }
 
 DIE *DwarfCompileUnit::constructImportedEntityDIE(
diff --git a/lib/CodeGen/AsmPrinter/DwarfDebug.h b/lib/CodeGen/AsmPrinter/DwarfDebug.h
index 9ba2a2b..b3b37c6 100644
--- a/lib/CodeGen/AsmPrinter/DwarfDebug.h
+++ b/lib/CodeGen/AsmPrinter/DwarfDebug.h
@@ -259,7 +259,7 @@
   // 0, referencing the comp_dir of all the type units that use it.
   MCDwarfDwoLineTable SplitTypeUnitFileTable;
   /// @}
-  
+
   /// True iff there are multiple CUs in this module.
   bool SingleCU;
   bool IsDarwin;
@@ -518,6 +518,9 @@
   /// going to be null.
   bool isLexicalScopeDIENull(LexicalScope *Scope);
 
+  /// Find the matching DwarfCompileUnit for the given CU DIE.
+  DwarfCompileUnit *lookupCU(const DIE *Die) { return CUDieMap.lookup(Die); }
+
   /// \defgroup DebuggerTuning Predicates to tune DWARF for a given debugger.
   ///
   /// Returns whether we are "tuning" for a given debugger.
diff --git a/test/DebugInfo/cross-cu-scope.ll b/test/DebugInfo/cross-cu-scope.ll
new file mode 100644
index 0000000..83e82a5
--- /dev/null
+++ b/test/DebugInfo/cross-cu-scope.ll
@@ -0,0 +1,50 @@
+; RUN: %llc_dwarf %s -filetype=obj -o %t
+; RUN: llvm-dwarfdump -debug-info %t | FileCheck %s
+
+; Reduced test case from PR35212. Two DISubprogram belong to a different CU but
+; share a scope. Both are declarations and end up in the scope's CU. We want to
+; check that the CU from the context DIE is used (rather than from the IR).
+; This manifests itself by the DW_base_type ending up in the second CU, rather
+; than in the first one as specified in the IR.
+
+; CHECK: DW_TAG_compile_unit
+; CHECK-NEXT: discriminator 0
+; CHECK: DW_TAG_compile_unit
+; CHECK-NEXT: discriminator 1
+; CHECK: DW_TAG_structure_type
+; CHECK-NOT: NULL
+; CHECK: DW_TAG_subprogram
+; CHECK-NOT: NULL
+; CHECK: DW_TAG_formal_parameter
+; CHECK-NOT: NULL
+; CHECK: DW_AT_type{{.*}}"usize"
+; CHECK: NULL
+; CHECK: DW_TAG_base_type
+; CHECK-NOT: NULL
+; CHECK: DW_AT_name{{.*}}"usize"
+
+define hidden void @foo() !dbg !4 {
+  ret void, !dbg !7
+}
+
+!llvm.dbg.cu = !{!0, !2}
+!llvm.module.flags = !{!3}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_Rust, file: !1, producer: "clang LLVM (rustc version 1.23.0-nightly (discriminator 0))", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug)
+!1 = !DIFile(filename: "../lib.rs", directory: "/home/alex/code/rust4/lol")
+!2 = distinct !DICompileUnit(language: DW_LANG_Rust, file: !1, producer: "clang LLVM (rustc version 1.23.0-nightly (discriminator 1))", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug)
+!3 = !{i32 2, !"Debug Info Version", i32 3}
+!4 = distinct !DISubprogram(name: "clone<alloc::string::String>", linkageName: "_ZN5alloc3vec8{{impl}}28clone<alloc::string::String>E", scope: null, file: !1, line: 1519, type: !5, isLocal: false, isDefinition: true, scopeLine: 1519, flags: DIFlagPrototyped, isOptimized: true, unit: !0, templateParams: !6, variables: !6)
+!5 = !DISubroutineType(types: !6)
+!6 = !{}
+!7 = !DILocation(line: 1612, scope: !8, inlinedAt: !11)
+!8 = distinct !DILexicalBlock(scope: !9, file: !1, line: 86, column: 12)
+!9 = distinct !DISubprogram(name: "allocate_in<alloc::string::String,alloc::heap::Heap>", linkageName: "_ZN5alloc7raw_vec8{{impl}}52allocate_in<alloc::string::String,alloc::heap::Heap>E", scope: !10, file: !1, line: 82, type: !5, isLocal: false, isDefinition: true, scopeLine: 82, flags: DIFlagPrototyped, isOptimized: true, unit: !2, templateParams: !6, variables: !6)
+!10 = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "RawVec<alloc::string::String, alloc::heap::Heap>", file: !1, size: 128, align: 64, elements: !6, identifier: "5c6e4db16d2c64555e40661d70c4d81e")
+!11 = distinct !DILocation(line: 86, scope: !8, inlinedAt: !12)
+!12 = distinct !DILocation(line: 141, scope: !13, inlinedAt: !17)
+!13 = distinct !DISubprogram(name: "with_capacity<alloc::string::String>", linkageName: "_ZN5alloc7raw_vec8{{impl}}36with_capacity<alloc::string::String>E", scope: !10, file: !1, line: 140, type: !5, isLocal: false, isDefinition: true, scopeLine: 140, flags: DIFlagPrototyped, isOptimized: true, unit: !0, templateParams: !6, variables: !14)
+!14 = !{!15}
+!15 = !DILocalVariable(name: "cap", arg: 1, scope: !13, file: !1, line: 1, type: !16)
+!16 = !DIBasicType(name: "usize", size: 64, encoding: DW_ATE_unsigned)
+!17 = !DILocation(line: 1521, scope: !4)