DebugInfo: Remove 'inlinedAt:' field from MDLocalVariable
Remove 'inlinedAt:' from MDLocalVariable. Besides saving some memory
(variables with it seem to be single largest `Metadata` contributer to
memory usage right now in -g -flto builds), this stops optimization and
backend passes from having to change local variables.
The 'inlinedAt:' field was used by the backend in two ways:
1. To tell the backend whether and into what a variable was inlined.
2. To create a unique id for each inlined variable.
Instead, rely on the 'inlinedAt:' field of the intrinsic's `!dbg`
attachment, and change the DWARF backend to use a typedef called
`InlinedVariable` which is `std::pair<MDLocalVariable*, MDLocation*>`.
This `DebugLoc` is already passed reliably through the backend (as
verified by r234021).
This commit removes the check from r234021, but I added a new check
(that will survive) in r235048, and changed the `DIBuilder` API in
r235041 to require a `!dbg` attachment whose 'scope:` is in the same
`MDSubprogram` as the variable's.
If this breaks your out-of-tree testcases, perhaps the script I used
(mdlocalvariable-drop-inlinedat.sh) will help; I'll attach it to PR22778
in a moment.
llvm-svn: 235050
diff --git a/llvm/test/Transforms/Mem2Reg/ConvertDebugInfo2.ll b/llvm/test/Transforms/Mem2Reg/ConvertDebugInfo2.ll
index 2e7a6e6..e60acc4 100644
--- a/llvm/test/Transforms/Mem2Reg/ConvertDebugInfo2.ll
+++ b/llvm/test/Transforms/Mem2Reg/ConvertDebugInfo2.ll
@@ -41,15 +41,15 @@
!6 = !MDBasicType(tag: DW_TAG_base_type, name: "int", size: 32, align: 32, encoding: DW_ATE_signed)
!7 = !MDLocation(line: 8, scope: !1)
!8 = !MDLocation(line: 9, scope: !1)
-!9 = !MDLocalVariable(tag: DW_TAG_arg_variable, name: "x", line: 4, arg: 0, scope: !10, file: !2, type: !6, inlinedAt: !8)
+!9 = !MDLocalVariable(tag: DW_TAG_arg_variable, name: "x", line: 4, arg: 0, scope: !10, file: !2, type: !6)
!10 = !MDSubprogram(name: "bar", linkageName: "bar", line: 4, isLocal: true, isDefinition: true, virtualIndex: 6, isOptimized: false, scopeLine: 4, file: !20, scope: !2, type: !11)
!11 = !MDSubroutineType(types: !12)
!12 = !{null, !6, !13, !14}
!13 = !MDBasicType(tag: DW_TAG_base_type, name: "long int", size: 64, align: 64, encoding: DW_ATE_signed)
!14 = !MDDerivedType(tag: DW_TAG_pointer_type, size: 64, align: 64, file: !20, scope: !2, baseType: null)
!15 = !MDLocation(line: 4, scope: !10, inlinedAt: !8)
-!16 = !MDLocalVariable(tag: DW_TAG_arg_variable, name: "y", line: 4, arg: 0, scope: !10, file: !2, type: !13, inlinedAt: !8)
-!17 = !MDLocalVariable(tag: DW_TAG_arg_variable, name: "z", line: 4, arg: 0, scope: !10, file: !2, type: !14, inlinedAt: !8)
+!16 = !MDLocalVariable(tag: DW_TAG_arg_variable, name: "y", line: 4, arg: 0, scope: !10, file: !2, type: !13)
+!17 = !MDLocalVariable(tag: DW_TAG_arg_variable, name: "z", line: 4, arg: 0, scope: !10, file: !2, type: !14)
!18 = !MDLocation(line: 5, scope: !10, inlinedAt: !8)
!19 = !MDLocation(line: 10, scope: !1)
!20 = !MDFile(filename: "bar.c", directory: "/tmp/")