This patch introduces "DBG_PHI" instructions, a marker of where a PHI instruction used to be, before PHI elimination. Under the instruction referencing model, we want to know where every value in the function is defined -- and a PHI, even if implicit, is such a place. Just like instruction numbers, we can use this to identify a value to be used as a variable value, but we don't need to know what instruction defines that value, for example: bb1: DBG_PHI $rax, 1 [... more insts ... ] bb2: DBG_INSTR_REF 1, 0, !1234, !DIExpression() This specifies that on entry to bb1, whatever value is in $rax is known as value number one -- and the later DBG_INSTR_REF marks the position where variable !1234 should take on value number one. PHI locations are stored in MachineFunction for the duration of the regalloc phase in the DebugPHIPositions map. The map is populated by PHIElimination, and then flushed back into the instruction stream by virtregrewriter. A small amount of maintenence is needed in LiveDebugVariables to account for registers being split, but only for individual positions, not for entire ranges of blocks. Differential Revision: https://reviews.llvm.org/D86812
154 lines
6.1 KiB
YAML
154 lines
6.1 KiB
YAML
# RUN: llc %s -o - -mtriple=x86_64-unknown-unknown \
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# RUN: -experimental-debug-variable-locations \
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# RUN: -run-pass=phi-node-elimination,livedebugvars,greedy,virtregrewriter \
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# RUN: | FileCheck %s
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#
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# Like phi-through-regalloc.mir, pass a PHI node into register allocation, and
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# test that it correctly comes out, in a stack slot. Fifteen spurious PHIs have
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# been added to force the register allocator to spill one.
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--- |
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; ModuleID = 'promoted.ll'
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source_filename = "test.c"
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target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
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target triple = "x86_64-unknown-linux-gnu"
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define dso_local i32 @foo(i32 %bar, i32 %baz) !dbg !7 {
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entry:
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ret i32 0, !dbg !19
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}
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declare dso_local i32 @ext(i32)
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; Function Attrs: nounwind readnone speculatable willreturn
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declare void @llvm.dbg.value(metadata, metadata, metadata)
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!llvm.dbg.cu = !{!0}
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!llvm.module.flags = !{!3, !4, !5}
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!llvm.ident = !{!6}
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!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, splitDebugInlining: false, nameTableKind: None)
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!1 = !DIFile(filename: "test.c", directory: ".")
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!2 = !{}
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!3 = !{i32 7, !"Dwarf Version", i32 4}
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!4 = !{i32 2, !"Debug Info Version", i32 3}
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!5 = !{i32 1, !"wchar_size", i32 4}
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!6 = !{!"."}
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!7 = distinct !DISubprogram(name: "foo", scope: !1, file: !1, line: 2, type: !8, scopeLine: 2, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !0, retainedNodes: !2)
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!8 = !DISubroutineType(types: !9)
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!9 = !{!10, !10, !10}
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!10 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
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!11 = !DILocalVariable(name: "bar", arg: 1, scope: !7, file: !1, line: 2, type: !10)
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!12 = !DILocation(line: 0, scope: !7)
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!13 = !DILocalVariable(name: "baz", arg: 2, scope: !7, file: !1, line: 2, type: !10)
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!14 = !DILocalVariable(name: "either", scope: !7, file: !1, line: 3, type: !10)
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!15 = !DILocation(line: 4, column: 7, scope: !16)
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!16 = distinct !DILexicalBlock(scope: !7, file: !1, line: 4, column: 7)
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!17 = !DILocation(line: 4, column: 7, scope: !7)
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!18 = !DILocation(line: 0, scope: !16)
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!19 = !DILocation(line: 9, column: 3, scope: !7)
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...
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---
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name: foo
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alignment: 16
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tracksRegLiveness: true
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registers:
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- { id: 0, class: gr32 }
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- { id: 1, class: gr32 }
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- { id: 2, class: gr32 }
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- { id: 3, class: gr32 }
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- { id: 4, class: gr32 }
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liveins:
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- { reg: '$edi', virtual-reg: '%1' }
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- { reg: '$esi', virtual-reg: '%2' }
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frameInfo:
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maxAlignment: 1
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hasCalls: true
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machineFunctionInfo: {}
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body: |
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; CHECK-LABEL: bb.0:
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; CHECK: renamable $ebp = COPY $edi
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; CHECK: MOV32mr %stack.1, 1, $noreg, 0, $noreg, killed renamable $ebp
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bb.0:
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successors: %bb.2(0x50000000), %bb.1(0x30000000)
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liveins: $edi, $esi
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DBG_VALUE $edi, $noreg, !11, !DIExpression(), debug-location !12
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DBG_VALUE $esi, $noreg, !13, !DIExpression(), debug-location !12
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%2:gr32 = COPY killed $esi
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DBG_VALUE %2, $noreg, !13, !DIExpression(), debug-location !12
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%1:gr32 = COPY killed $edi
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DBG_VALUE %1, $noreg, !11, !DIExpression(), debug-location !12
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DBG_VALUE 0, $noreg, !14, !DIExpression(), debug-location !12
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ADJCALLSTACKDOWN64 0, 0, 0, implicit-def dead $rsp, implicit-def dead $eflags, implicit-def dead $ssp, implicit $rsp, implicit $ssp, debug-location !15
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%3:gr32 = MOV32r0 implicit-def dead $eflags
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$edi = COPY killed %3, debug-location !15
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CALL64pcrel32 @ext, csr_64, implicit $rsp, implicit $ssp, implicit killed $edi, implicit-def $rsp, implicit-def $ssp, implicit-def $eax, debug-location !15
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ADJCALLSTACKUP64 0, 0, implicit-def dead $rsp, implicit-def dead $eflags, implicit-def dead $ssp, implicit $rsp, implicit $ssp, debug-location !15
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%4:gr32 = COPY killed $eax, debug-location !15
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%10:gr32 = MOV32ri 0
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%11:gr32 = MOV32ri 1
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%12:gr32 = MOV32ri 2
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%13:gr32 = MOV32ri 3
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%14:gr32 = MOV32ri 4
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%15:gr32 = MOV32ri 5
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%16:gr32 = MOV32ri 6
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%17:gr32 = MOV32ri 7
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%18:gr32 = MOV32ri 8
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%19:gr32 = MOV32ri 9
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%20:gr32 = MOV32ri 10
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%21:gr32 = MOV32ri 11
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%22:gr32 = MOV32ri 12
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%23:gr32 = MOV32ri 13
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%24:gr32 = MOV32ri 14
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TEST32rr killed %4, %4, implicit-def $eflags, debug-location !15
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JCC_1 %bb.2, 5, implicit killed $eflags, debug-location !17
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JMP_1 %bb.1, debug-location !17
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bb.1:
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DBG_VALUE %2, $noreg, !14, !DIExpression(), debug-location !12
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%30:gr32 = MOV32ri 0
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%31:gr32 = MOV32ri 1
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%32:gr32 = MOV32ri 2
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%33:gr32 = MOV32ri 3
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%34:gr32 = MOV32ri 4
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%35:gr32 = MOV32ri 5
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%36:gr32 = MOV32ri 6
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%37:gr32 = MOV32ri 7
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%38:gr32 = MOV32ri 8
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%39:gr32 = MOV32ri 9
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%40:gr32 = MOV32ri 10
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%41:gr32 = MOV32ri 11
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%42:gr32 = MOV32ri 12
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%43:gr32 = MOV32ri 13
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%44:gr32 = MOV32ri 14
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; CHECK-LABEL: bb.2:
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bb.2:
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%0:gr32 = PHI %1, %bb.0, %2, %bb.1, debug-instr-number 1, debug-location !18
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%50:gr32 = PHI %10, %bb.0, %30, %bb.1, debug-location !18
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%51:gr32 = PHI %11, %bb.0, %31, %bb.1, debug-location !18
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%52:gr32 = PHI %12, %bb.0, %32, %bb.1, debug-location !18
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%53:gr32 = PHI %13, %bb.0, %33, %bb.1, debug-location !18
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%54:gr32 = PHI %14, %bb.0, %34, %bb.1, debug-location !18
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%55:gr32 = PHI %15, %bb.0, %35, %bb.1, debug-location !18
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%56:gr32 = PHI %16, %bb.0, %36, %bb.1, debug-location !18
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%57:gr32 = PHI %17, %bb.0, %37, %bb.1, debug-location !18
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%58:gr32 = PHI %18, %bb.0, %38, %bb.1, debug-location !18
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%59:gr32 = PHI %19, %bb.0, %39, %bb.1, debug-location !18
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%60:gr32 = PHI %20, %bb.0, %40, %bb.1, debug-location !18
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%61:gr32 = PHI %21, %bb.0, %41, %bb.1, debug-location !18
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%62:gr32 = PHI %22, %bb.0, %42, %bb.1, debug-location !18
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%63:gr32 = PHI %23, %bb.0, %43, %bb.1, debug-location !18
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%64:gr32 = PHI %24, %bb.0, %44, %bb.1, debug-location !18
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DBG_INSTR_REF 1, 0, !14, !DIExpression(), debug-location !12
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; CHECK: DBG_PHI %stack.1, 1
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; CHECK: renamable $eax = MOV32rm %stack.1,
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; CHECK: DBG_INSTR_REF 1, 0
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$eax = COPY killed %0, debug-location !19
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RET 0, killed $eax, debug-location !19
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...
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