DwarfCompileUnit: Fix another assertion failure on malformed input

that is not rejected by the Verifier.

Thanks to Björn Pettersson for providing a reproducer!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@331535 91177308-0d34-0410-b5e6-96231b3b80d8

lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp

@@ -234,7 +234,7 @@ DIE *DwarfCompileUnit::getOrCreateGlobalVariableDIE(
     // It would be better if this were unconditional, but malformed input that
     // mixes non-fragments and fragments for the same variable is too expensive
     // to detect in the verifier.
-    if (!DwarfExpr->isMemoryLocation())
+    if (DwarfExpr->isUnknownLocation())
       DwarfExpr->setMemoryLocationKind();
     DwarfExpr->addExpression(Expr);
   }

lib/CodeGen/AsmPrinter/DwarfExpression.h

@@ -212,6 +212,7 @@ class DwarfExpression {
   void addUnsignedConstant(const APInt &Value);
 
   bool isMemoryLocation() const { return LocationKind == Memory; }
+  bool isUnknownLocation() const { return LocationKind == Unknown; }
 
   /// Lock this down to become a memory location description.
   void setMemoryLocationKind() {

test/DebugInfo/X86/global-expression.ll

@@ -17,7 +17,7 @@ target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
 target triple = "x86_64-apple-macosx10.13.0"
 
 @i = global i32 23, align 4
-@indirect = global i32* @i, align 8, !dbg !6, !dbg !0, !dbg !14, !dbg !15
+@indirect = global i32* @i, align 8, !dbg !6, !dbg !0, !dbg !14, !dbg !15, !dbg !16
 
 !llvm.dbg.cu = !{!2}
 !llvm.module.flags = !{!10, !11, !12, !13}
@@ -39,3 +39,4 @@ target triple = "x86_64-apple-macosx10.13.0"
 ; This is malformed, but too expensive to detect in the verifier.
 !14 = !DIGlobalVariableExpression(var: !7, expr: !DIExpression())
 !15 = !DIGlobalVariableExpression(var: !7, expr: !DIExpression(DW_OP_LLVM_fragment, 0, 1))
+!16 = !DIGlobalVariableExpression(var: !7, expr: !DIExpression(DW_OP_deref, DW_OP_constu, 1, DW_OP_plus, DW_OP_stack_value))