[IR] Remove the DIExpression field from DIGlobalVariable.

This patch implements PR31013 by introducing a
DIGlobalVariableExpression that holds a pair of DIGlobalVariable and
DIExpression.

Currently, DIGlobalVariables holds a DIExpression. This is not the
best way to model this:

(1) The DIGlobalVariable should describe the source level variable,
    not how to get to its location.

(2) It makes it unsafe/hard to update the expressions when we call
    replaceExpression on the DIGLobalVariable.

(3) It makes it impossible to represent a global variable that is in
    more than one location (e.g., a variable with multiple
    DW_OP_LLVM_fragment-s).  We also moved away from attaching the
    DIExpression to DILocalVariable for the same reasons.

This reapplies r289902 with additional testcase upgrades.

<rdar://problem/29250149>
https://llvm.org/bugs/show_bug.cgi?id=31013
Differential Revision: https://reviews.llvm.org/D26769

llvm-svn: 289920

1 files changed, 1 insertions, 1 deletions

diff --git a/llvm/test/DebugInfo/X86/inline-namespace.ll b/llvm/test/DebugInfo/X86/inline-namespace.ll
index 627e6f8931f..1e9a0e61257 100644
--- a/llvm/test/DebugInfo/X86/inline-namespace.ll
+++ b/llvm/test/DebugInfo/X86/inline-namespace.ll
@@ -26,7 +26,7 @@ target triple = "x86_64-apple-macosx10.12.0"
 !llvm.module.flags = !{!8, !9, !10}
 !llvm.ident = !{!11}
 
-!0 = distinct !DIGlobalVariable(name: "i", linkageName: "_ZN6normal7inlined1iE", scope: !1, file: !2, line: 1, type: !4, isLocal: false, isDefinition: true)
+!0 = distinct !DIGlobalVariableExpression(var: !DIGlobalVariable(name: "i", linkageName: "_ZN6normal7inlined1iE", scope: !1, file: !2, line: 1, type: !4, isLocal: false, isDefinition: true))
 !1 = !DINamespace(name: "inlined", scope: !3, file: !2, line: 1, exportSymbols: true)
 !2 = !DIFile(filename: "namespace.cpp", directory: "/")
 !3 = !DINamespace(name: "normal", scope: null, file: !2, line: 1)