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clang-p2996/llvm/test/DebugInfo/MIR/X86/debug-entry-value-operation.mir
Jeremy Morse 1575583f2a [LiveDebugValues][InstrRef][2/2] Emit entry value variable locations
This patch adds support to the instruction-referencing LiveDebugValues
implementation for emitting entry values. The instruction referencing
implementations tracking by value rather than location means that we can
get around two of the issues with VarLocs. DBG_VALUE instructions that
re-assign the same value to a variable are no longer a problem, because we
can "see through" to the value being assigned. We also don't need to do
anything special during the dataflow stages: the "variable value problem"
doesn't need to know whether a value is available most of the time, and the
times it deoes need to know are always when entry values need to be
terminated.

The patch modifies the "TransferTracker" class, adding methods to identify
when a variable ias an entry value candidate, and when a machine value is
an entry value. recoverAsEntryValue tests these two things and emits an
entry-value expression if they're true. It's used when we clobber or
otherwise lose a value and can't find a replacement location for the value
it contained.

Differential Revision: https://reviews.llvm.org/D88406
2021-06-30 23:07:39 +01:00

94 lines
4.3 KiB
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# RUN: llc -start-before=livedebugvalues -mtriple=x86_64-apple-darwin -o %t %s -filetype=obj
# RUN: llvm-dwarfdump %t | FileCheck %s
# RUN: llc -force-instr-ref-livedebugvalues=1 -start-before=livedebugvalues -mtriple=x86_64-apple-darwin -o %t %s -filetype=obj
# RUN: llvm-dwarfdump %t | FileCheck %s
# RUN: llc -start-before=livedebugvalues -debugger-tune=sce -mtriple=x86_64-sce-ps4 -o %t1 %s -filetype=obj
# RUN: llvm-dwarfdump %t1 | FileCheck %s -check-prefix=SCE
# RUN: llc -force-instr-ref-livedebugvalues=1 -start-before=livedebugvalues -debugger-tune=sce -mtriple=x86_64-sce-ps4 -o %t1 %s -filetype=obj
# RUN: llvm-dwarfdump %t1 | FileCheck %s -check-prefix=SCE
## Based on:
## int global;
## int foo(int p, int q, int r) {
## global = p + 1;
## asm __volatile("" : : : "edi", "esi", "edx");
## return 123;
## }
# CHECK: DW_TAG_formal_parameter
# CHECK: DW_OP_entry_value
# SCE-NOT: DW_OP_{{.*}}entry_value
--- |
; ModuleID = 'multiple-param-dbg-value-entry.ll'
source_filename = "multiple-param-dbg-value-entry.c"
target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
@global = common dso_local local_unnamed_addr global i32 0, align 4, !dbg !0
define dso_local i32 @foo(i32 %p, i32 %q, i32 %r) local_unnamed_addr !dbg !11 {
entry:
call void @llvm.dbg.value(metadata i32 %p, metadata !15, metadata !DIExpression()), !dbg !18
call void @llvm.dbg.value(metadata i32 %q, metadata !16, metadata !DIExpression()), !dbg !18
call void @llvm.dbg.value(metadata i32 %r, metadata !17, metadata !DIExpression()), !dbg !18
%add = add nsw i32 %p, 1, !dbg !18
store i32 %add, i32* @global, align 4, !dbg !18
tail call void asm sideeffect "", "~{edi},~{esi},~{edx},~{dirflag},~{fpsr},~{flags}"(), !dbg !18, !srcloc !19
ret i32 123, !dbg !18
}
; Function Attrs: nounwind readnone speculatable
declare void @llvm.dbg.value(metadata, metadata, metadata)
!llvm.dbg.cu = !{!2}
!llvm.module.flags = !{!7, !8, !9}
!llvm.ident = !{!10}
!0 = !DIGlobalVariableExpression(var: !1, expr: !DIExpression())
!1 = distinct !DIGlobalVariable(name: "global", scope: !2, file: !3, line: 8, type: !6, isLocal: false, isDefinition: true)
!2 = distinct !DICompileUnit(language: DW_LANG_C99, file: !3, producer: "clang version 9.0.0 ", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !4, globals: !5, nameTableKind: None)
!3 = !DIFile(filename: "multiple-param-dbg-value-entry.c", directory: "/")
!4 = !{}
!5 = !{!0}
!6 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
!7 = !{i32 2, !"Dwarf Version", i32 4}
!8 = !{i32 2, !"Debug Info Version", i32 3}
!9 = !{i32 1, !"wchar_size", i32 4}
!10 = !{!"clang version 9.0.0 "}
!11 = distinct !DISubprogram(name: "foo", scope: !3, file: !3, line: 9, type: !12, scopeLine: 9, flags: DIFlagPrototyped | DIFlagAllCallsDescribed, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !2, retainedNodes: !14)
!12 = !DISubroutineType(types: !13)
!13 = !{!6, !6, !6, !6}
!14 = !{!15, !16, !17}
!15 = !DILocalVariable(name: "p", arg: 1, scope: !11, file: !3, line: 9, type: !6)
!16 = !DILocalVariable(name: "q", arg: 2, scope: !11, file: !3, line: 9, type: !6)
!17 = !DILocalVariable(name: "r", arg: 3, scope: !11, file: !3, line: 9, type: !6)
!18 = !DILocation(line: 9, column: 13, scope: !11)
!19 = !{i32 213}
...
---
name: foo
alignment: 16
tracksRegLiveness: true
liveins:
- { reg: '$edi' }
body: |
bb.0.entry:
liveins: $edi
DBG_VALUE $edi, $noreg, !15, !DIExpression(), debug-location !18
DBG_VALUE $edi, $noreg, !15, !DIExpression(), debug-location !18
DBG_VALUE $esi, $noreg, !16, !DIExpression(), debug-location !18
DBG_VALUE $edx, $noreg, !17, !DIExpression(), debug-location !18
renamable $edi = nsw INC32r killed renamable $edi, implicit-def dead $eflags, debug-location !18
MOV32mr $rip, 1, $noreg, @global, $noreg, killed renamable $edi, debug-location !18 :: (store (s32) into @global)
INLINEASM &"", 1, 12, implicit-def dead early-clobber $edi, 12, implicit-def dead early-clobber $esi, 12, implicit-def dead early-clobber $edx, 12, implicit-def dead early-clobber $df, 12, implicit-def dead early-clobber $fpsw, 12, implicit-def dead early-clobber $eflags, !19, debug-location !18
$eax = MOV32ri 123, debug-location !18
RETQ killed $eax, debug-location !18
...