From 4f5d67b3e414cf5f2c9f7440e97837b718bda4cc Mon Sep 17 00:00:00 2001 From: Eli Friedman Date: Sun, 13 Jul 2025 16:06:27 -0700 Subject: [PATCH] [AArch64] "Support" debug info for SVE types on Windows. (#147865) There isn't any way to encode a variable in an SVE register, and there isn't any way to encode a scalable offset, and as far as I know that's unlikely to change in the near future. So suppress any debug info which would require those encodings. This isn't ideal, but we need to ship something which doesn't crash. Alternatively, for Z registers, we could emit debug info assuming the vector length is 128 bits, but that seems like it would lead to unintuitive results. The change to AArch64FrameLowering is needed to avoid a crash. But we can't actually test that the returned offset is correct: LiveDebugValues performs the query, then discards the result. --- .../include/llvm/CodeGen/TargetRegisterInfo.h | 4 + llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp | 11 +- .../Target/AArch64/AArch64FrameLowering.cpp | 6 +- .../Target/AArch64/AArch64RegisterInfo.cpp | 5 + llvm/lib/Target/AArch64/AArch64RegisterInfo.h | 2 + .../DebugInfo/COFF/AArch64/codeview-sve.ll | 161 ++++++++++++++++++ 6 files changed, 185 insertions(+), 4 deletions(-) create mode 100644 llvm/test/DebugInfo/COFF/AArch64/codeview-sve.ll diff --git a/llvm/include/llvm/CodeGen/TargetRegisterInfo.h b/llvm/include/llvm/CodeGen/TargetRegisterInfo.h index 8b9ed78a8e97..12ee51f13026 100644 --- a/llvm/include/llvm/CodeGen/TargetRegisterInfo.h +++ b/llvm/include/llvm/CodeGen/TargetRegisterInfo.h @@ -1243,6 +1243,10 @@ public: getVRegFlagsOfReg(Register Reg, const MachineFunction &MF) const { return {}; } + + // Whether this register should be ignored when generating CodeView debug + // info, because it's a known there is no mapping available. + virtual bool isIgnoredCVReg(MCRegister LLVMReg) const { return false; } }; //===----------------------------------------------------------------------===// diff --git a/llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp b/llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp index bc74daf983e4..8abeb56adeac 100644 --- a/llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp +++ b/llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp @@ -1318,8 +1318,10 @@ void CodeViewDebug::collectVariableInfoFromMFTable( TFI->getFrameIndexReference(*Asm->MF, VI.getStackSlot(), FrameReg); uint16_t CVReg = TRI->getCodeViewRegNum(FrameReg); - assert(!FrameOffset.getScalable() && - "Frame offsets with a scalable component are not supported"); + if (FrameOffset.getScalable()) { + // No encoding currently exists for scalable offsets; bail out. + continue; + } // Calculate the label ranges. LocalVarDef DefRange = @@ -1410,6 +1412,11 @@ void CodeViewDebug::calculateRanges( if (Location->FragmentInfo->OffsetInBits % 8) continue; + if (TRI->isIgnoredCVReg(Location->Register)) { + // No encoding currently exists for this register; bail out. + continue; + } + LocalVarDef DR; DR.CVRegister = TRI->getCodeViewRegNum(Location->Register); DR.InMemory = !Location->LoadChain.empty(); diff --git a/llvm/lib/Target/AArch64/AArch64FrameLowering.cpp b/llvm/lib/Target/AArch64/AArch64FrameLowering.cpp index 0179be4894c9..885f2a94f85f 100644 --- a/llvm/lib/Target/AArch64/AArch64FrameLowering.cpp +++ b/llvm/lib/Target/AArch64/AArch64FrameLowering.cpp @@ -3043,9 +3043,11 @@ StackOffset AArch64FrameLowering::resolveFrameOffsetReference( StackOffset::get(MFI.getStackSize() - AFI->getCalleeSavedStackSize(), ObjectOffset); if (FPAfterSVECalleeSaves) { - assert(-ObjectOffset > (int64_t)AFI->getSVECalleeSavedStackSize() && - "Math isn't correct for CSRs with FPAfterSVECalleeSaves"); FPOffset += StackOffset::getScalable(AFI->getSVECalleeSavedStackSize()); + if (-ObjectOffset <= (int64_t)AFI->getSVECalleeSavedStackSize()) { + FPOffset += StackOffset::getFixed(AFI->getCalleeSavedStackSize()); + SPOffset += StackOffset::getFixed(AFI->getCalleeSavedStackSize()); + } } // Always use the FP for SVE spills if available and beneficial. if (hasFP(MF) && (SPOffset.getFixed() || diff --git a/llvm/lib/Target/AArch64/AArch64RegisterInfo.cpp b/llvm/lib/Target/AArch64/AArch64RegisterInfo.cpp index dd23bf51a98c..77dfab83a834 100644 --- a/llvm/lib/Target/AArch64/AArch64RegisterInfo.cpp +++ b/llvm/lib/Target/AArch64/AArch64RegisterInfo.cpp @@ -1370,3 +1370,8 @@ bool AArch64RegisterInfo::shouldAnalyzePhysregInMachineLoopInfo( MCRegister R) const { return R == AArch64::VG; } + +bool AArch64RegisterInfo::isIgnoredCVReg(MCRegister LLVMReg) const { + return (LLVMReg >= AArch64::Z0 && LLVMReg <= AArch64::Z31) || + (LLVMReg >= AArch64::P0 && LLVMReg <= AArch64::P15); +} diff --git a/llvm/lib/Target/AArch64/AArch64RegisterInfo.h b/llvm/lib/Target/AArch64/AArch64RegisterInfo.h index cc94be611a2e..1ed8e959fdd2 100644 --- a/llvm/lib/Target/AArch64/AArch64RegisterInfo.h +++ b/llvm/lib/Target/AArch64/AArch64RegisterInfo.h @@ -154,6 +154,8 @@ public: SmallVectorImpl &Ops) const override; bool shouldAnalyzePhysregInMachineLoopInfo(MCRegister R) const override; + + virtual bool isIgnoredCVReg(MCRegister LLVMReg) const override; }; } // end namespace llvm diff --git a/llvm/test/DebugInfo/COFF/AArch64/codeview-sve.ll b/llvm/test/DebugInfo/COFF/AArch64/codeview-sve.ll new file mode 100644 index 000000000000..446a84dc0294 --- /dev/null +++ b/llvm/test/DebugInfo/COFF/AArch64/codeview-sve.ll @@ -0,0 +1,161 @@ +; RUN: llc < %s -filetype=obj | llvm-readobj --codeview - | FileCheck %s + +; The point of this is mostly just to avoid crashing... there isn't any way +; to encode most of the information we want to encode. But we try to do what +; we can. +; +; Generated from: +; +; #include +; void g(); +; svint32_t f(svint32_t aaa, svint32_t bbb, svint32_t *ccc) { +; asm("":::"z0", "z1", "z2", "z3", "z4", "z5", "z6", "z7", "z8", "z9", +; "z10", "z11", "z12", "z13", "z14", "z15", "z16", "z17", "z18", +; "z19", "z20", "z21", "z22", "z23", "z24", "z25", "z26", "z27", +; "z28", "z29", "z30", "z31"); +; return aaa**ccc+bbb; +;} + +; Emit the SVE type. We represent this as an array with unknown bound. + +; CHECK: Array (0x1000) { +; CHECK-NEXT: TypeLeafKind: LF_ARRAY (0x1503) +; CHECK-NEXT: ElementType: int (0x74) +; CHECK-NEXT: IndexType: unsigned __int64 (0x23) +; CHECK-NEXT: SizeOf: 0 +; CHECK-NEXT: Name: +; CHECK-NEXT: } + +; Emit frame information. This is missing the size of the SVE +; variables, but we can't really do anything about that. + +; CHECK: FrameProcSym { +; CHECK-NEXT: Kind: S_FRAMEPROC (0x1012) +; CHECK-NEXT: TotalFrameBytes: 0x10 +; CHECK-NEXT: PaddingFrameBytes: 0x0 +; CHECK-NEXT: OffsetToPadding: 0x0 +; CHECK-NEXT: BytesOfCalleeSavedRegisters: 0x0 +; CHECK-NEXT: OffsetOfExceptionHandler: 0x0 +; CHECK-NEXT: SectionIdOfExceptionHandler: 0x0 +; CHECK-NEXT: Flags [ (0x116008) +; CHECK-NEXT: HasInlineAssembly (0x8) +; CHECK-NEXT: OptimizedForSpeed (0x100000) +; CHECK-NEXT: SafeBuffers (0x2000) +; CHECK-NEXT: ] +; CHECK-NEXT: LocalFramePtrReg: ARM64_NOREG (0x0) +; CHECK-NEXT: ParamFramePtrReg: ARM64_NOREG (0x0) +; CHECK-NEXT: } + +; Emit the symbols for the local variables. +; +; ccc is a normal pointer. +; +; We can't represent bbb anywhere in its range; there's no way to name Z +; registers, and no way to express its location on the stack relative +; to the stack pointer when it's spilled. +; +; In the middle of the range, aaa happens to have a scalable offset of zero, +; so we can represent it while it's on the stack. + +; CHECK-NEXT: LocalSym { +; CHECK-NEXT: Kind: S_LOCAL (0x113E) +; CHECK-NEXT: Type: 0x1000 +; CHECK-NEXT: Flags [ (0x1) +; CHECK-NEXT: IsParameter (0x1) +; CHECK-NEXT: ] +; CHECK-NEXT: VarName: aaa +; CHECK-NEXT: } +; CHECK-NEXT: DefRangeRegisterRelSym { +; CHECK-NEXT: Kind: S_DEFRANGE_REGISTER_REL (0x1145) +; CHECK-NEXT: BaseRegister: ARM64_SP (0x51) +; CHECK-NEXT: HasSpilledUDTMember: No +; CHECK-NEXT: OffsetInParent: 0 +; CHECK-NEXT: BasePointerOffset: 0 +; CHECK-NEXT: LocalVariableAddrRange { +; CHECK-NEXT: OffsetStart: .text+0x58 +; CHECK-NEXT: ISectStart: 0x0 +; CHECK-NEXT: Range: 0xC +; CHECK-NEXT: } +; CHECK-NEXT: } +; CHECK-NEXT: LocalSym { +; CHECK-NEXT: Kind: S_LOCAL (0x113E) +; CHECK-NEXT: Type: 0x1000 +; CHECK-NEXT: Flags [ (0x101) +; CHECK-NEXT: IsOptimizedOut (0x100) +; CHECK-NEXT: IsParameter (0x1) +; CHECK-NEXT: ] +; CHECK-NEXT: VarName: bbb +; CHECK-NEXT: } +; CHECK-NEXT: LocalSym { +; CHECK-NEXT: Kind: S_LOCAL (0x113E) +; CHECK-NEXT: Type: * (0x1001) +; CHECK-NEXT: Flags [ (0x1) +; CHECK-NEXT: IsParameter (0x1) +; CHECK-NEXT: ] +; CHECK-NEXT: VarName: ccc +; CHECK-NEXT: } +; CHECK-NEXT: DefRangeRegisterSym { +; CHECK-NEXT: Kind: S_DEFRANGE_REGISTER (0x1141) +; CHECK-NEXT: Register: ARM64_X0 (0x32) +; CHECK-NEXT: MayHaveNoName: 0 +; CHECK-NEXT: LocalVariableAddrRange { +; CHECK-NEXT: OffsetStart: .text+0x0 +; CHECK-NEXT: ISectStart: 0x0 +; CHECK-NEXT: Range: 0xBC +; CHECK-NEXT: } +; CHECK-NEXT: } +; CHECK-NEXT: ProcEnd { +; CHECK-NEXT: Kind: S_PROC_ID_END (0x114F) +; CHECK-NEXT: } + +target triple = "aarch64-unknown-windows-msvc19.33.0" + +; Function Attrs: mustprogress nounwind uwtable vscale_range(1,16) +define dso_local @"?f@@YAU__SVInt32_t@__clang@@U12@0PEAU12@@Z"( %aaa, %bbb, ptr noundef readonly captures(none) %ccc) local_unnamed_addr #0 !dbg !10 { +entry: + #dbg_value(ptr %ccc, !23, !DIExpression(), !26) + #dbg_value( %bbb, !24, !DIExpression(), !26) + #dbg_value( %aaa, !25, !DIExpression(), !26) + tail call void asm sideeffect "", "~{z0},~{z1},~{z2},~{z3},~{z4},~{z5},~{z6},~{z7},~{z8},~{z9},~{z10},~{z11},~{z12},~{z13},~{z14},~{z15},~{z16},~{z17},~{z18},~{z19},~{z20},~{z21},~{z22},~{z23},~{z24},~{z25},~{z26},~{z27},~{z28},~{z29},~{z30},~{z31}"() #1, !dbg !27, !srcloc !28 + %0 = load , ptr %ccc, align 16, !dbg !27 + %mul = mul %0, %aaa, !dbg !27 + %add = add %mul, %bbb, !dbg !27 + ret %add, !dbg !27 +} + +attributes #0 = { mustprogress nounwind uwtable vscale_range(1,16) "frame-pointer"="non-leaf" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="generic" "target-features"="+fp-armv8,+fullfp16,+neon,+sve,+v8a,-fmv" } +attributes #1 = { nounwind } + +!llvm.dbg.cu = !{!0} +!llvm.module.flags = !{!2, !3, !4, !5, !6, !7, !8} +!llvm.ident = !{!9} + +!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus_14, file: !1, producer: "clang version 21.0.0git", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, splitDebugInlining: false, nameTableKind: None) +!1 = !DIFile(filename: "-", directory: "", checksumkind: CSK_MD5, checksum: "e54fc2ba768e4a43f64b8a9d03a374d6") +!2 = !{i32 2, !"CodeView", i32 1} +!3 = !{i32 2, !"Debug Info Version", i32 3} +!4 = !{i32 1, !"wchar_size", i32 2} +!5 = !{i32 8, !"PIC Level", i32 2} +!6 = !{i32 7, !"uwtable", i32 2} +!7 = !{i32 7, !"frame-pointer", i32 1} +!8 = !{i32 7, !"debug-info-assignment-tracking", i1 true} +!9 = !{!"clang version 21.0.0git"} +!10 = distinct !DISubprogram(name: "f", linkageName: "?f@@YAU__SVInt32_t@__clang@@U12@0PEAU12@@Z", scope: !11, file: !11, line: 2, type: !12, scopeLine: 2, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0, retainedNodes: !22) +!11 = !DIFile(filename: "", directory: "", checksumkind: CSK_MD5, checksum: "e54fc2ba768e4a43f64b8a9d03a374d6") +!12 = !DISubroutineType(types: !13) +!13 = !{!14, !14, !14, !21} +!14 = !DIDerivedType(tag: DW_TAG_typedef, name: "svint32_t", file: !15, line: 30, baseType: !16) +!15 = !DIFile(filename: "arm_sve.h", directory: "", checksumkind: CSK_MD5, checksum: "34027e9d24f4b03c6e5370869d5cc907") +!16 = !DIDerivedType(tag: DW_TAG_typedef, name: "__SVInt32_t", file: !1, baseType: !17) +!17 = !DICompositeType(tag: DW_TAG_array_type, baseType: !18, flags: DIFlagVector, elements: !19) +!18 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed) +!19 = !{!20} +!20 = !DISubrange(lowerBound: 0, upperBound: !DIExpression(DW_OP_constu, 2, DW_OP_bregx, 46, 0, DW_OP_mul, DW_OP_constu, 1, DW_OP_minus)) +!21 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !14, size: 64) +!22 = !{!23, !24, !25} +!23 = !DILocalVariable(name: "ccc", arg: 3, scope: !10, file: !11, line: 2, type: !21) +!24 = !DILocalVariable(name: "bbb", arg: 2, scope: !10, file: !11, line: 2, type: !14) +!25 = !DILocalVariable(name: "aaa", arg: 1, scope: !10, file: !11, line: 2, type: !14) +!26 = !DILocation(line: 0, scope: !10) +!27 = !DILocation(line: 2, scope: !10) +!28 = !{i64 98}