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Fix a fragment overflow problem when composing super-registers. #3862

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Merged
merged 1 commit into from
Feb 2, 2022
Merged

Fix a fragment overflow problem when composing super-registers. #3862

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8 changes: 8 additions & 0 deletions llvm/lib/CodeGen/AsmPrinter/DwarfExpression.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -287,9 +287,17 @@ bool DwarfExpression::addMachineRegExpression(const TargetRegisterInfo &TRI,
// expression representing a value, rather than a location.
if ((!isParameterValue() && !isMemoryLocation() && !HasComplexExpression) ||
isEntryValue()) {
auto FragmentInfo = ExprCursor.getFragmentInfo();
unsigned RegSize = 0;
for (auto &Reg : DwarfRegs) {
RegSize += Reg.SubRegSize;
if (Reg.DwarfRegNo >= 0)
addReg(Reg.DwarfRegNo, Reg.Comment);
if (FragmentInfo)
if (RegSize > FragmentInfo->SizeInBits)
// If the register is larger than the current fragment stop
// once the fragment is covered.
break;
addOpPiece(Reg.SubRegSize);
}

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34 changes: 34 additions & 0 deletions llvm/test/DebugInfo/MIR/AArch64/subreg-fragment-overflow.mir
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@@ -0,0 +1,34 @@
# RUN: llc -mtriple aarch64-linux-gnu -start-after=livedebugvalues -filetype=obj -o - %s \
# RUN: | llvm-dwarfdump - | FileCheck %s
# The value needs to be composed of sub-registers, but the
# sub-registers cross the fragment boundary.
# CHECK: DW_OP_piece 0x8, DW_OP_regx B16, DW_OP_piece 0x8
--- |
target triple = "aarch64-none-linux-android21"
define linkonce_odr dso_local void @_f() !dbg !1590 {
entry:
ret void, !dbg !1809
}
declare i32 @__gxx_personality_v0(...)
!llvm.dbg.cu = !{!0}
!llvm.module.flags = !{!1586,!1587}
!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus_14, file: !1, emissionKind: FullDebug, splitDebugInlining: false, nameTableKind: None)
!1 = !DIFile(filename: "bug.cpp", directory: "/")
!1586 = !{i32 2, !"Debug Info Version", i32 3}
!1587 = !{i32 7, !"frame-pointer", i32 1}
!1590 = distinct !DISubprogram(name: "f", scope: !0, file: !1, line: 278, type: !1591, scopeLine: 279, flags: DIFlagPrototyped, unit: !0, declaration: !1593)
!1591 = !DISubroutineType(types: !1592)
!1592 = !{null }
!1593 = !DISubprogram(name: "f", linkageName: "_f", scope: !0, file: !1, line: 195, type: !1591, scopeLine: 195, flags:
DIFlagProtected
, spFlags: DISPFlagOptimized)
!1694 = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "uint8x8x3_t", file: !1, line: 235, size: 192, flags: DIFlagTypePassByValue, elements: !1695, identifier: "_ZTS11uint8x8x3_t")
!1695 = !{}
!1715 = !DILocalVariable(name: "__ret", scope: !1590, file: !1, line: 379, type: !1694)
!1809 = !DILocation(line: 0, scope: !1590 )
---
name: _f
body: |
bb.0.entry:
renamable $d16_d17_d18 = LD3Threev8b killed renamable $x15, debug-location !1809
DBG_VALUE $d16_d17_d18, $noreg, !1715, !DIExpression(DW_OP_LLVM_fragment, 64, 64), debug-location !1809