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llvm-mirror/test/DebugInfo/X86/lexical_block.ll
Adrian Prantl 2b1df58ebe 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
2014-10-01 18:55:02 +00:00

68 lines
3.5 KiB
LLVM

; REQUIRES: object-emission
; RUN: llc -mtriple=x86_64-linux -O0 -filetype=obj < %s \
; RUN: | llvm-dwarfdump -debug-dump=info - | FileCheck --check-prefix=CHECK --check-prefix=CHECK-V4 %s
; RUN: llc -mtriple=x86_64-linux -dwarf-version=3 -O0 -filetype=obj < %s \
; RUN: | llvm-dwarfdump -debug-dump=info - | FileCheck --check-prefix=CHECK --check-prefix=CHECK-V3 %s
; Check that we emit DW_TAG_lexical_block and that it has the right encoding
; depending on the dwarf version.
; CHECK: DW_TAG_lexical_block
; CHECK-NOT: DW_TAG
; CHECK: DW_AT_low_pc [DW_FORM_addr]
; CHECK-NOT: DW_TAG
; CHECK-V4: DW_AT_high_pc [DW_FORM_data4]
; CHECK-V3: DW_AT_high_pc [DW_FORM_addr]
; Test case produced from:
; void b() {
; if (int i = 3)
; return;
; }
; Function Attrs: nounwind uwtable
define void @_Z1bv() #0 {
entry:
%i = alloca i32, align 4
call void @llvm.dbg.declare(metadata !{i32* %i}, metadata !11, metadata !{i32 786690}), !dbg !14
store i32 3, i32* %i, align 4, !dbg !14
%0 = load i32* %i, align 4, !dbg !14
%tobool = icmp ne i32 %0, 0, !dbg !14
br i1 %tobool, label %if.then, label %if.end, !dbg !14
if.then: ; preds = %entry
br label %if.end, !dbg !15
if.end: ; preds = %if.then, %entry
ret void, !dbg !16
}
; Function Attrs: nounwind readnone
declare void @llvm.dbg.declare(metadata, metadata, metadata) #1
attributes #0 = { nounwind uwtable "less-precise-fpmad"="false" "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf" "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 = !{!8, !9}
!llvm.ident = !{!10}
!0 = metadata !{i32 786449, metadata !1, i32 4, metadata !"clang version 3.5.0 ", i1 false, metadata !"", i32 0, metadata !2, metadata !2, metadata !3, metadata !2, metadata !2, metadata !"", i32 1} ; [ DW_TAG_compile_unit ] [/tmp/dbginfo/lexical_block.cpp] [DW_LANG_C_plus_plus]
!1 = metadata !{metadata !"lexical_block.cpp", metadata !"/tmp/dbginfo"}
!2 = metadata !{}
!3 = metadata !{metadata !4}
!4 = metadata !{i32 786478, metadata !1, metadata !5, metadata !"b", metadata !"b", metadata !"_Z1bv", i32 1, metadata !6, i1 false, i1 true, i32 0, i32 0, null, i32 256, i1 false, void ()* @_Z1bv, null, null, metadata !2, i32 1} ; [ DW_TAG_subprogram ] [line 1] [def] [b]
!5 = metadata !{i32 786473, metadata !1} ; [ DW_TAG_file_type ] [/tmp/dbginfo/lexical_block.cpp]
!6 = metadata !{i32 786453, i32 0, null, metadata !"", i32 0, i64 0, i64 0, i64 0, i32 0, null, metadata !7, i32 0, null, null, null} ; [ DW_TAG_subroutine_type ] [line 0, size 0, align 0, offset 0] [from ]
!7 = metadata !{null}
!8 = metadata !{i32 2, metadata !"Dwarf Version", i32 4}
!9 = metadata !{i32 1, metadata !"Debug Info Version", i32 1}
!10 = metadata !{metadata !"clang version 3.5.0 "}
!11 = metadata !{i32 786688, metadata !12, metadata !"i", metadata !5, i32 2, metadata !13, i32 0, i32 0} ; [ DW_TAG_auto_variable ] [i] [line 2]
!12 = metadata !{i32 786443, metadata !1, metadata !4, i32 2, i32 0, i32 0, i32 0} ; [ DW_TAG_lexical_block ] [/tmp/dbginfo/lexical_block.cpp]
!13 = metadata !{i32 786468, null, null, metadata !"int", i32 0, i64 32, i64 32, i64 0, i32 0, i32 5} ; [ DW_TAG_base_type ] [int] [line 0, size 32, align 32, offset 0, enc DW_ATE_signed]
!14 = metadata !{i32 2, i32 0, metadata !12, null}
!15 = metadata !{i32 3, i32 0, metadata !12, null}
!16 = metadata !{i32 4, i32 0, metadata !4, null}