[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, 3 insertions, 3 deletions

diff --git a/llvm/test/Transforms/SimplifyCFG/PR27615-simplify-cond-br.ll b/llvm/test/Transforms/SimplifyCFG/PR27615-simplify-cond-br.ll
index 94e32dedb61..d2da83963b3 100644
--- a/llvm/test/Transforms/SimplifyCFG/PR27615-simplify-cond-br.ll
+++ b/llvm/test/Transforms/SimplifyCFG/PR27615-simplify-cond-br.ll
@@ -46,13 +46,13 @@ declare void @llvm.dbg.value(metadata, i64, metadata, metadata) #4
 !1 = !DIFile(filename: "csmith107.i.c", directory: "/tmp")
 !2 = !{}
 !3 = !{!4, !6, !10}
-!4 = !DIGlobalVariable(name: "a", scope: null, file: !1, line: 2, type: !5, isLocal: false, isDefinition: true)
+!4 = !DIGlobalVariableExpression(var: !DIGlobalVariable(name: "a", scope: null, file: !1, line: 2, type: !5, isLocal: false, isDefinition: true))
 !5 = !DIBasicType(name: "int", size: 16, align: 16, encoding: DW_ATE_signed)
-!6 = !DIGlobalVariable(name: "b", scope: null, file: !1, line: 3, type: !7, isLocal: false, isDefinition: true)
+!6 = !DIGlobalVariableExpression(var: !DIGlobalVariable(name: "b", scope: null, file: !1, line: 3, type: !7, isLocal: false, isDefinition: true))
 !7 = !DIDerivedType(tag: DW_TAG_typedef, name: "uint32_t", file: !1, line: 1, baseType: !8)
 !8 = !DIDerivedType(tag: DW_TAG_typedef, name: "__u32_t", file: !1, baseType: !9)
 !9 = !DIBasicType(name: "unsigned long", size: 32, align: 16, encoding: DW_ATE_unsigned)
-!10 = !DIGlobalVariable(name: "c", scope: null, file: !1, line: 4, type: !11, isLocal: false, isDefinition: true)
+!10 = !DIGlobalVariableExpression(var: !DIGlobalVariable(name: "c", scope: null, file: !1, line: 4, type: !11, isLocal: false, isDefinition: true))
 !11 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !5, size: 16, align: 16)
 !12 = !{i32 2, !"Dwarf Version", i32 4}
 !13 = !{i32 2, !"Debug Info Version", i32 3}