llvm-6502/test/Transforms/Inline/inline_dbg_declare.ll
David Blaikie f93662d3d5 DebugInfo: Use distinct inlinedAt MDLocations to avoid separate inlined calls being coalesced
When two calls from the same MDLocation are inlined they currently get
treated as one inlined function call (creating difficulty debugging,
duplicate variables, etc).

Clang worked around this by including column information on inline calls
which doesn't address LTO inlining or calls to the same function from
the same line and column (such as through a macro). It also didn't
address ctor and member function calls.

By making the inlinedAt locations distinct, every call site has an
explicitly distinct location that cannot be coalesced with any other
call.

This can produce linearly (2x in the worst case where every call is
inlined and the call instruction has a non-call instruction at the same
location) more debug locations. Any increase beyond that are in cases
where the Clang workaround was insufficient and the new scheme is
creating necessary distinct nodes that were being erroneously coalesced
previously.

After this change to LLVM the incomplete workarounds in Clang. That
should reduce the number of debug locations (in a build without column
info, the default on Darwin, not the default on Linux) by not creating
pseudo-distinct locations for every call to an inline function.

(oh, and I made the inlined-at chain rebuilding iterative instead of
recursive because I was having trouble wrapping my head around it the
way it was - open to discussion on the right design for that function
(including going back to a recursive solution))

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@226736 91177308-0d34-0410-b5e6-96231b3b80d8
2015-01-21 22:57:29 +00:00

98 lines
4.1 KiB
LLVM

; RUN: opt < %s -S -inline | FileCheck %s
;
; The purpose of this test is to check that inline pass preserves debug info
; for variable using the dbg.declare intrinsic.
;
;; This test was generated by running this command:
;; clang.exe -S -O0 -emit-llvm -g foo.c
;;
;; foo.c
;; ==========================
;; float foo(float x)
;; {
;; return x;
;; }
;;
;; void bar(float *dst)
;; {
;; dst[0] = foo(dst[0]);
;; }
;; ==========================
target datalayout = "e-m:w-p:32:32-i64:64-f80:32-n8:16:32-S32"
target triple = "i686-pc-windows-msvc"
; Function Attrs: nounwind
define float @foo(float %x) #0 {
entry:
%x.addr = alloca float, align 4
store float %x, float* %x.addr, align 4
call void @llvm.dbg.declare(metadata float* %x.addr, metadata !16, metadata !17), !dbg !18
%0 = load float* %x.addr, align 4, !dbg !19
ret float %0, !dbg !19
}
; Function Attrs: nounwind readnone
declare void @llvm.dbg.declare(metadata, metadata, metadata) #1
; CHECK: define void @bar
; Function Attrs: nounwind
define void @bar(float* %dst) #0 {
entry:
; CHECK: [[x_addr_i:%[a-zA-Z0-9.]+]] = alloca float, align 4
%dst.addr = alloca float*, align 4
store float* %dst, float** %dst.addr, align 4
call void @llvm.dbg.declare(metadata float** %dst.addr, metadata !20, metadata !17), !dbg !21
%0 = load float** %dst.addr, align 4, !dbg !22
%arrayidx = getelementptr inbounds float* %0, i32 0, !dbg !22
%1 = load float* %arrayidx, align 4, !dbg !22
%call = call float @foo(float %1), !dbg !22
; CHECK-NOT: call float @foo
; CHECK: void @llvm.dbg.declare(metadata float* [[x_addr_i]], metadata [[m23:![0-9]+]], metadata !17), !dbg [[m24:![0-9]+]]
%2 = load float** %dst.addr, align 4, !dbg !22
%arrayidx1 = getelementptr inbounds float* %2, i32 0, !dbg !22
store float %call, float* %arrayidx1, align 4, !dbg !22
ret void, !dbg !23
}
attributes #0 = { nounwind }
attributes #1 = { nounwind readnone }
!llvm.dbg.cu = !{!0}
!llvm.module.flags = !{!13, !14}
!llvm.ident = !{!15}
!0 = !{!"0x11\0012\00clang version 3.6.0 (trunk)\000\00\000\00\001", !1, !2, !2, !3, !2, !2} ; [ DW_TAG_compile_unit ] [foo.c] [DW_LANG_C99]
!1 = !{!"foo.c", !""}
!2 = !{}
!3 = !{!4, !9}
!4 = !{!"0x2e\00foo\00foo\00\001\000\001\000\000\00256\000\002", !1, !5, !6, null, float (float)* @foo, null, null, !2} ; [ DW_TAG_subprogram ] [line 1] [def] [scope 2] [foo]
!5 = !{!"0x29", !1} ; [ DW_TAG_file_type ] [foo.c]
!6 = !{!"0x15\00\000\000\000\000\000\000", null, null, null, !7, null, null, null} ; [ DW_TAG_subroutine_type ] [line 0, size 0, align 0, offset 0] [from ]
!7 = !{!8, !8}
!8 = !{!"0x24\00float\000\0032\0032\000\000\004", null, null} ; [ DW_TAG_base_type ] [float] [line 0, size 32, align 32, offset 0, enc DW_ATE_float]
!9 = !{!"0x2e\00bar\00bar\00\006\000\001\000\000\00256\000\007", !1, !5, !10, null, void (float*)* @bar, null, null, !2} ; [ DW_TAG_subprogram ] [line 6] [def] [scope 7] [bar]
!10 = !{!"0x15\00\000\000\000\000\000\000", null, null, null, !11, null, null, null} ; [ DW_TAG_subroutine_type ] [line 0, size 0, align 0, offset 0] [from ]
!11 = !{null, !12}
!12 = !{!"0xf\00\000\0032\0032\000\000", null, null, !8} ; [ DW_TAG_pointer_type ] [line 0, size 32, align 32, offset 0] [from float]
!13 = !{i32 2, !"Dwarf Version", i32 4}
!14 = !{i32 2, !"Debug Info Version", i32 2}
!15 = !{!"clang version 3.6.0 (trunk)"}
!16 = !{!"0x101\00x\0016777217\000", !4, !5, !8} ; [ DW_TAG_arg_variable ] [x] [line 1]
!17 = !{!"0x102"} ; [ DW_TAG_expression ]
!18 = !MDLocation(line: 1, column: 17, scope: !4)
!19 = !MDLocation(line: 3, column: 5, scope: !4)
!20 = !{!"0x101\00dst\0016777222\000", !9, !5, !12} ; [ DW_TAG_arg_variable ] [dst] [line 6]
!21 = !MDLocation(line: 6, column: 17, scope: !9)
!22 = !MDLocation(line: 8, column: 14, scope: !9)
!23 = !MDLocation(line: 9, column: 1, scope: !9)
; CHECK: [[m23]] = !{!"0x101\00x\0016777217\000", !4, !5, !8, [[CALL_SITE:![0-9]*]]} ; [ DW_TAG_arg_variable ] [x] [line 1]
; CHECK: [[CALL_SITE]] = distinct !MDLocation(line: 8, column: 14, scope: !9)
; CHECK: [[m24]] = !MDLocation(line: 1, column: 17, scope: !4, inlinedAt: [[CALL_SITE]])