[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.

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

llvm-svn: 289902

1 files changed, 1 insertions, 1 deletions

diff --git a/llvm/test/DebugInfo/X86/InlinedFnLocalVar.ll b/llvm/test/DebugInfo/X86/InlinedFnLocalVar.ll
index c95a7e08db0..bac5a873448 100644
--- a/llvm/test/DebugInfo/X86/InlinedFnLocalVar.ll
+++ b/llvm/test/DebugInfo/X86/InlinedFnLocalVar.ll
@@ -45,7 +45,7 @@ entry:
 !13 = !{!14, !15}
 !14 = !DIDerivedType(tag: DW_TAG_member, name: "a", line: 10, size: 32, align: 32, file: !27, scope: !12, baseType: !5)
 !15 = !DIDerivedType(tag: DW_TAG_member, name: "b", line: 10, size: 32, align: 32, offset: 32, file: !27, scope: !12, baseType: !5)
-!16 = !DIGlobalVariable(name: "i", line: 5, isLocal: false, isDefinition: true, scope: !1, file: !1, type: !5)
+!16 = !DIGlobalVariableExpression(var: !DIGlobalVariable(name: "i", line: 5, isLocal: false, isDefinition: true, scope: !1, file: !1, type: !5))
 !17 = !DILocation(line: 15, scope: !18)
 !18 = distinct !DILexicalBlock(line: 14, column: 0, file: !1, scope: !6)
 !19 = !DILocation(line: 9, scope: !0, inlinedAt: !17)