[llvm] 1de516d - [StackColoring] Pre-commit of test case showing a debug invariance bug
Bjorn Pettersson via llvm-commits
llvm-commits at lists.llvm.org
Tue Sep 14 10:25:08 PDT 2021
Author: Bjorn Pettersson
Date: 2021-09-14T19:21:55+02:00
New Revision: 1de516d7ae7e568a0ae28b79d2a91521bff79689
URL: https://github.com/llvm/llvm-project/commit/1de516d7ae7e568a0ae28b79d2a91521bff79689
DIFF: https://github.com/llvm/llvm-project/commit/1de516d7ae7e568a0ae28b79d2a91521bff79689.diff
LOG: [StackColoring] Pre-commit of test case showing a debug invariance bug
Having DBG_VALUE instructions referencing a stack slot while being outside
of the LIFETIME_START/LIFETIME_END markers for that stack slot is perhaps
not always ideal (from a debugging perspective), but it might happen during
codegen that we end up with such situations (e.g. positioning of the
DBG_VALUE instruction for a SDDbgOperand::FRAMEIX at ISel is a bit sloppy
in that context).
This patch adds a test case showing that StackColoring currently isn't
debug invariant, and that the position of DBG_VALUE instructions referencing
the stack slots might impact the decision making regarding stack slot reuse.
Differential Revision: https://reviews.llvm.org/D109757
Added:
llvm/test/CodeGen/X86/StackColoring-dbg-invariance.mir
Modified:
Removed:
################################################################################
diff --git a/llvm/test/CodeGen/X86/StackColoring-dbg-invariance.mir b/llvm/test/CodeGen/X86/StackColoring-dbg-invariance.mir
new file mode 100644
index 0000000000000..8f250a690c33f
--- /dev/null
+++ b/llvm/test/CodeGen/X86/StackColoring-dbg-invariance.mir
@@ -0,0 +1,117 @@
+# NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py
+# RUN: llc -mcpu=corei7 -no-stack-coloring=false -run-pass=stack-coloring -o - %s | FileCheck %s
+
+# Difference between test_1 and test_2 is that there is a DBG_VALUE in test_1.
+# If transformation is debug invariant the resulting LEA instruction should be
+# the same (i.e. we should reuse the same stack slot).
+
+--- |
+ ; ModuleID = '<stdin>'
+ source_filename = "StackColoring-dbg-invariance.ll"
+ target datalayout = "e-m:o-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
+ target triple = "x86_64-apple-macosx10.8.0"
+
+ ; Function Attrs: argmemonly nofree nosync nounwind willreturn
+ declare void @llvm.lifetime.start.p0i8(i64 immarg, i8* nocapture) #0
+
+ ; Function Attrs: argmemonly nofree nosync nounwind willreturn
+ declare void @llvm.lifetime.end.p0i8(i64 immarg, i8* nocapture) #0
+
+ define i32 @test_1(i32 %in) #1 !dbg !5 {
+ entry:
+ %a1 = alloca [14 x i8*], align 8
+ %a4 = alloca [11 x i8*], align 8
+ call void @llvm.dbg.value(metadata [11 x i8*]* %a4, metadata !9, metadata !DIExpression()), !dbg !11
+ ret i32 0
+ }
+
+ define i32 @test_2(i32 %in) #1 !dbg !12 {
+ entry:
+ %a1 = alloca [14 x i8*], align 8
+ %a4 = alloca [11 x i8*], align 8
+ ret i32 0
+ }
+
+ ; Function Attrs: nofree nosync nounwind readnone speculatable willreturn
+ declare void @llvm.dbg.value(metadata, metadata, metadata) #2
+
+ attributes #0 = { argmemonly nofree nosync nounwind willreturn "target-cpu"="corei7" }
+ attributes #1 = { "target-cpu"="corei7" }
+
+ !llvm.dbg.cu = !{!0}
+ !llvm.debugify = !{!2, !3}
+ !llvm.module.flags = !{!4}
+
+ !0 = distinct !DICompileUnit(language: DW_LANG_C, file: !1, producer: "debugify", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug)
+ !1 = !DIFile(filename: "StackColoring-dbg-invariance.ll", directory: "/")
+ !2 = !{i32 27}
+ !3 = !{i32 18}
+ !4 = !{i32 2, !"Debug Info Version", i32 3}
+ !5 = distinct !DISubprogram(name: "test_1", linkageName: "test_1", scope: null, file: !1, line: 1, type: !6, scopeLine: 1, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0, retainedNodes: !8)
+ !6 = !DISubroutineType(types: !7)
+ !7 = !{}
+ !8 = !{!9}
+ !9 = !DILocalVariable(name: "4", scope: !5, file: !1, line: 4, type: !10)
+ !10 = !DIBasicType(name: "ty64", size: 64, encoding: DW_ATE_unsigned)
+ !11 = !DILocation(line: 4, column: 1, scope: !5)
+ !12 = distinct !DISubprogram(name: "test_2", linkageName: "test_2", scope: null, file: !1, line: 1, type: !6, scopeLine: 1, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0, retainedNodes: !8)
+
+...
+---
+name: test_1
+alignment: 16
+tracksRegLiveness: true
+stack:
+ - { id: 0, name: a1, type: default, offset: 0, size: 112, alignment: 8,
+ stack-id: default, callee-saved-register: '', callee-saved-restored: true,
+ debug-info-variable: '', debug-info-expression: '', debug-info-location: '' }
+ - { id: 3, name: a4, type: default, offset: 0, size: 88, alignment: 8,
+ stack-id: default, callee-saved-register: '', callee-saved-restored: true,
+ debug-info-variable: '', debug-info-expression: '', debug-info-location: '' }
+body: |
+ bb.0.entry:
+ liveins: $edi
+
+ ; CHECK-LABEL: name: test_1
+ ; CHECK: liveins: $edi
+ ; CHECK: DBG_VALUE %stack.1.a4, $noreg, !9, !DIExpression(), debug-location !11
+ ; CHECK: [[LEA64r:%[0-9]+]]:gr64 = LEA64r %stack.0.a1, 1, $noreg, 0, $noreg
+ ; CHECK: [[LEA64r1:%[0-9]+]]:gr64 = LEA64r %stack.1.a4, 1, $noreg, 0, $noreg
+ ; CHECK: RET 0
+ DBG_VALUE %stack.3.a4, $noreg, !9, !DIExpression(), debug-location !11
+ LIFETIME_START %stack.3.a4
+ LIFETIME_START %stack.0.a1
+ %0:gr64 = LEA64r %stack.0.a1, 1, $noreg, 0, $noreg
+ LIFETIME_END %stack.0.a1
+ %1:gr64 = LEA64r %stack.3.a4, 1, $noreg, 0, $noreg
+ LIFETIME_END %stack.3.a4
+ RET 0
+...
+---
+name: test_2
+alignment: 16
+tracksRegLiveness: true
+stack:
+ - { id: 0, name: a1, type: default, offset: 0, size: 112, alignment: 8,
+ stack-id: default, callee-saved-register: '', callee-saved-restored: true,
+ debug-info-variable: '', debug-info-expression: '', debug-info-location: '' }
+ - { id: 3, name: a4, type: default, offset: 0, size: 88, alignment: 8,
+ stack-id: default, callee-saved-register: '', callee-saved-restored: true,
+ debug-info-variable: '', debug-info-expression: '', debug-info-location: '' }
+body: |
+ bb.0.entry:
+ liveins: $edi
+
+ ; CHECK-LABEL: name: test_2
+ ; CHECK: liveins: $edi
+ ; CHECK: [[LEA64r:%[0-9]+]]:gr64 = LEA64r %stack.0.a1, 1, $noreg, 0, $noreg
+ ; CHECK: [[LEA64r1:%[0-9]+]]:gr64 = LEA64r %stack.0.a1, 1, $noreg, 0, $noreg
+ ; CHECK: RET 0
+ LIFETIME_START %stack.3.a4
+ LIFETIME_START %stack.0.a1
+ %0:gr64 = LEA64r %stack.0.a1, 1, $noreg, 0, $noreg
+ LIFETIME_END %stack.0.a1
+ %1:gr64 = LEA64r %stack.3.a4, 1, $noreg, 0, $noreg
+ LIFETIME_END %stack.3.a4
+ RET 0
+...
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