llvm-project/llvm/test/DebugInfo/dead-argument-order.ll

82 lines
4.3 KiB
LLVM
Raw Normal View History

; REQUIRES: object-emission
; RUN: %llc_dwarf -O0 -filetype=obj < %s | llvm-dwarfdump -debug-dump=info - | FileCheck %s
; Built from the following source with clang -O1
; struct S { int i; };
; int function(struct S s, int i) { return s.i + i; }
; Due to the X86_64 ABI, 's' is passed in registers and once optimized, the
; entirety of 's' is never reconstituted, since only the int is required, and
; thus the variable's location is unknown/dead to debug info.
; Future/current work should enable us to describe partial variables, which, in
; this case, happens to be the entire variable.
; CHECK: DW_TAG_subprogram
; CHECK-NOT: DW_TAG
; CHECK: DW_AT_name {{.*}} "function"
; CHECK-NOT: {{DW_TAG|NULL}}
; CHECK: DW_TAG_formal_parameter
; CHECK-NOT: DW_TAG
; CHECK: DW_AT_name {{.*}} "s"
; CHECK-NOT: DW_TAG
; FIXME: Even though 's' is never reconstituted into a struct, the one member
; variable is still live and used, and so we should be able to describe 's's
; location as the location of that int.
; CHECK-NOT: DW_AT_location
; CHECK-NOT: {{DW_TAG|NULL}}
; CHECK: DW_TAG_formal_parameter
; CHECK-NOT: DW_TAG
; CHECK: DW_AT_location
; CHECK-NOT: DW_TAG
; CHECK: DW_AT_name {{.*}} "i"
%struct.S = type { i32 }
; Function Attrs: nounwind readnone uwtable
define i32 @_Z8function1Si(i32 %s.coerce, i32 %i) #0 {
entry:
tail call void @llvm.dbg.declare(metadata !19, metadata !14, metadata !{metadata !"0x102"}), !dbg !20
tail call void @llvm.dbg.value(metadata !{i32 %i}, i64 0, metadata !15, metadata !{metadata !"0x102"}), !dbg !20
%add = add nsw i32 %i, %s.coerce, !dbg !20
ret i32 %add, !dbg !20
}
; Function Attrs: nounwind readnone
Move the complex address expression out of DIVariable and into an extra argument of the llvm.dbg.declare/llvm.dbg.value intrinsics. Previously, DIVariable was a variable-length field that has an optional reference to a Metadata array consisting of a variable number of complex address expressions. In the case of OpPiece expressions this is wasting a lot of storage in IR, because when an aggregate type is, e.g., SROA'd into all of its n individual members, the IR will contain n copies of the DIVariable, all alike, only differing in the complex address reference at the end. By making the complex address into an extra argument of the dbg.value/dbg.declare intrinsics, all of the pieces can reference the same variable and the complex address expressions can be uniqued across the CU, too. Down the road, this will allow us to move other flags, such as "indirection" out of the DIVariable, too. The new intrinsics look like this: declare void @llvm.dbg.declare(metadata %storage, metadata %var, metadata %expr) declare void @llvm.dbg.value(metadata %storage, i64 %offset, metadata %var, metadata %expr) This patch adds a new LLVM-local tag to DIExpressions, so we can detect and pretty-print DIExpression metadata nodes. What this patch doesn't do: This patch does not touch the "Indirect" field in DIVariable; but moving that into the expression would be a natural next step. http://reviews.llvm.org/D4919 rdar://problem/17994491 Thanks to dblaikie and dexonsmith for reviewing this patch! Note: I accidentally committed a bogus older version of this patch previously. llvm-svn: 218787
2014-10-02 02:55:02 +08:00
declare void @llvm.dbg.declare(metadata, metadata, metadata) #1
; Function Attrs: nounwind readnone
Move the complex address expression out of DIVariable and into an extra argument of the llvm.dbg.declare/llvm.dbg.value intrinsics. Previously, DIVariable was a variable-length field that has an optional reference to a Metadata array consisting of a variable number of complex address expressions. In the case of OpPiece expressions this is wasting a lot of storage in IR, because when an aggregate type is, e.g., SROA'd into all of its n individual members, the IR will contain n copies of the DIVariable, all alike, only differing in the complex address reference at the end. By making the complex address into an extra argument of the dbg.value/dbg.declare intrinsics, all of the pieces can reference the same variable and the complex address expressions can be uniqued across the CU, too. Down the road, this will allow us to move other flags, such as "indirection" out of the DIVariable, too. The new intrinsics look like this: declare void @llvm.dbg.declare(metadata %storage, metadata %var, metadata %expr) declare void @llvm.dbg.value(metadata %storage, i64 %offset, metadata %var, metadata %expr) This patch adds a new LLVM-local tag to DIExpressions, so we can detect and pretty-print DIExpression metadata nodes. What this patch doesn't do: This patch does not touch the "Indirect" field in DIVariable; but moving that into the expression would be a natural next step. http://reviews.llvm.org/D4919 rdar://problem/17994491 Thanks to dblaikie and dexonsmith for reviewing this patch! Note: I accidentally committed a bogus older version of this patch previously. llvm-svn: 218787
2014-10-02 02:55:02 +08:00
declare void @llvm.dbg.value(metadata, i64, metadata, metadata) #1
attributes #0 = { nounwind readnone uwtable "less-precise-fpmad"="false" "no-frame-pointer-elim"="false" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "stack-protector-buffer-size"="8" "unsafe-fp-math"="false" "use-soft-float"="false" }
attributes #1 = { nounwind readnone }
!llvm.dbg.cu = !{!0}
!llvm.module.flags = !{!16, !17}
!llvm.ident = !{!18}
!0 = metadata !{metadata !"0x11\004\00clang version 3.5.0 \001\00\000\00\001", metadata !1, metadata !2, metadata !3, metadata !8, metadata !2, metadata !2} ; [ DW_TAG_compile_unit ] [/tmp/dbginfo/dead-argument-order.cpp] [DW_LANG_C_plus_plus]
!1 = metadata !{metadata !"dead-argument-order.cpp", metadata !"/tmp/dbginfo"}
!2 = metadata !{}
!3 = metadata !{metadata !4}
!4 = metadata !{metadata !"0x13\00S\001\0032\0032\000\000\000", metadata !1, null, null, metadata !5, null, null, metadata !"_ZTS1S"} ; [ DW_TAG_structure_type ] [S] [line 1, size 32, align 32, offset 0] [def] [from ]
!5 = metadata !{metadata !6}
!6 = metadata !{metadata !"0xd\00i\001\0032\0032\000\000", metadata !1, metadata !"_ZTS1S", metadata !7} ; [ DW_TAG_member ] [i] [line 1, size 32, align 32, offset 0] [from int]
!7 = metadata !{metadata !"0x24\00int\000\0032\0032\000\000\005", null, null} ; [ DW_TAG_base_type ] [int] [line 0, size 32, align 32, offset 0, enc DW_ATE_signed]
!8 = metadata !{metadata !9}
!9 = metadata !{metadata !"0x2e\00function\00function\00_Z8function1Si\002\000\001\000\006\00256\001\002", metadata !1, metadata !10, metadata !11, null, i32 (i32, i32)* @_Z8function1Si, null, null, metadata !13} ; [ DW_TAG_subprogram ] [line 2] [def] [function]
!10 = metadata !{metadata !"0x29", metadata !1} ; [ DW_TAG_file_type ] [/tmp/dbginfo/dead-argument-order.cpp]
!11 = metadata !{metadata !"0x15\00\000\000\000\000\000\000", i32 0, null, null, metadata !12, null, null, null} ; [ DW_TAG_subroutine_type ] [line 0, size 0, align 0, offset 0] [from ]
!12 = metadata !{metadata !7, metadata !4, metadata !7}
!13 = metadata !{metadata !14, metadata !15}
!14 = metadata !{metadata !"0x101\00s\0016777218\000", metadata !9, metadata !10, metadata !"_ZTS1S"} ; [ DW_TAG_arg_variable ] [s] [line 2]
!15 = metadata !{metadata !"0x101\00i\0033554434\000", metadata !9, metadata !10, metadata !7} ; [ DW_TAG_arg_variable ] [i] [line 2]
!16 = metadata !{i32 2, metadata !"Dwarf Version", i32 4}
!17 = metadata !{i32 2, metadata !"Debug Info Version", i32 2}
!18 = metadata !{metadata !"clang version 3.5.0 "}
!19 = metadata !{%struct.S* undef}
!20 = metadata !{i32 2, i32 0, metadata !9, null}